Condition-Based Monitoring

The ADcmXL3021 is a complete vibration sensing system that combines high performance vibration sensing (using micro-electromechanical systems (MEMS) accelerometers) with a variety of signal processing functions to simplify the development of smart sensor nodes in condition-based monitoring (CBM) systems. The typical ultralow noise density (26 μg/√Hz) in the MEMS accelerometers supports excellent resolution. The wide bandwidth (dc to 10 kHz within 3 dB flatness) enables tracking of key vibration signatures on many machine platforms.

The signal processing includes high speed data sampling (220 kSPS), 4096 time sample record lengths, filtering, windowing, fast Fourier transform (FFT), user configurable spectral or time statistic alarms, and error flags. The serial peripheral interface (SPI) provides access to a register structure that contains the vibration data and a wide range of user configurable functions.

The ADcmXL3021 is available in a 23.7 mm × 27.0 mm × 12.4 mm aluminum package with four mounting flanges to support installation with standard machine screws. This package provides consistent mechanical coupling to the core sensors over a broad frequency range. The electrical interface is through a 14-pin connector on a 36 mm flexible cable, which enables a wide range of location and orientation options for system mating connectors.

The ADcmXL3021 requires only a single, 3.3 V power supply and supports an operating temperature range of −40°C to +105°C.

Applications

• Vibration analysis
• CBM systems
• Machine health
• Instrumentation and diagnostics
• Safety shutoff sensing

The ADXL1001/ADXL1002 deliver ultralow noise density over an extended frequency range with two full-scale range options, and are optimized for industrial condition monitoring. The ADXL1001 (±100 g) and the ADXL1002 (±50 g) have typical noise densities of 30 μg/√Hz and 25 μg/√Hz, respectively. Both accelerometer devices have stable and repeatable sensitivity, which is immune to external shocks up to 10,000 g.

The ADXL1001/ADXL1002 have an integrated full electrostatic self test (ST) function and an overrange (OR) indicator that allow advanced system level features and are useful for embedded applications. With low power and single-supply operation of 3.3 V to 5.25 V, the ADXL1001/ADXL1002 also enable wireless sensing product design. The ADXL1001/ ADXL1002 are available in a 5 mm × 5 mm × 1.80 mm LFCSP package, and are rated for operation over a −40°C to +125°C temperature range.

Applications

• Condition monitoring
• Predictive maintenance
• Asset health
• Test and measurement
• Health usage monitoring system (HUMS)

SmartMesh IP wireless sensor networks are self managing, low power internet protocol (IP) networks built from wireless nodes called motes. The LTP5901-IPM is printed circuit board assembly (PCBA) product with on-board chip antenna in the Eterna^® family of IEEE 802.15.4e solutions, featuring a highly integrated, low power radio design as well as an ARM Cortex-M3 32-bit microprocessor running SmartMesh IP embedded networking software. The LTP5901-IPM, at 24mm × 42mm, is built for surface-mount assembly.

With SmartMesh IP time-synchronized networks, all motes in the network may route, source or terminate data, while providing many years of battery powered operation. SmartMesh IP is a highly flexible network with proven reliability and low power performance in an easy-to-integrate platform.

The LTP5901-IPM’s behavior in a SmartMesh IP network is determined by the choice of SmartMesh IP network software loaded: Wireless Mote, EManager, or Access Point Mote in a SmartMesh IP network. The SmartMesh IP software provided with the LTP5901-IPM is fully tested and validated, and is readily configured via a software Application Programming Interface. Once you have purchased SmartMesh IP products, the SmartMesh IP stack binaries may be downloaded via your myAnalog account.

The pin signaling behavior of the LTP5901IPC-IPMA hardware is determined by the software loaded and is described in detail in the following product datasheets:

Network Features

Device Features

Applications

SmartMesh IP is ideally suited for wireless Industrial Internet of Things (IoT) applications. Learn more about SmartMesh applications.

SmartMesh WirelessHART wireless sensor networks are self managing, low power networks built from wireless nodes called motes. The LTP^™5901-WHM is the SmartMesh WirelessHART mote product in the Eterna^® family of IEEE 802.15.4 printed circuit board assembly solutions, featuring a highly-integrated, low power radio design by Analog Devices as well as an ARM Cortex-M3 32-bit microprocessor running Analog Devices' embedded SmartMesh WirelessHART networking software.

The LTP5901-WHM includes an onboard chip antenna and comes with modular RF certifications. Also available are the LTC5800-WHM Mote-on-Chip and the LTP5902-WHM module which includes an MMCX antenna connector.

With Analog Devices' time-synchronized SmartMesh WirelessHART networks, all motes in the network may route, source or terminate data, while providing many years of battery powered operation. The SmartMesh WirelessHART software provided with the LTP5901-WHM is fully tested and validated, and is readily configured via a software Application Programming Interface (API).

Network Features

Device Features

Applications

Learn more about SmartMesh applications.

The AD7768-1 is a low power, high performance, Σ-Δ analog-to-digital converter (ADC), with a Σ-Δ modulator and digital filter for precision conversion of both ac and dc signals. The AD7768-1 is a single-channel version of the AD7768, an 8-channel, simultaneously sampling, Σ-Δ ADC. The AD7768-1 provides a single configurable and reusable data acquisition (DAQ) footprint, which establishes a new industry standard in combined ac and dc performance and enables instrumentation and industrial system designers to design across multiple measurement variants for both isolated and nonisolated applications.

The AD7768-1 achieves a 108.5 dB dynamic range when using the low ripple, finite impulse response (FIR) digital filter at 256 kSPS, giving 110.8 kHz input bandwidth, combined with ±1.1 ppm integral nonlinearity (INL), ±30 µV offset error, and ±30 ppm gain error.

A wider bandwidth, up to 500 kHz Nyquist (filter −3 dB point of 204 kHz), is available using the sinc5 filter, enabling a view of signals over an extended range.

The AD7768-1 offers the user the flexibility to configure and optimize for input bandwidth vs. output data rate (ODR) and vs. power dissipation. The flexibility of the AD7768-1 allows dynamic analysis of a changing input signal, making the device particularly useful in general-purpose DAQ systems. The selection of one of three available power modes allows the designer to achieve required noise targets while minimizing power consumption. The design of the AD7768-1 is unique in that it becomes a reusable and flexible platform for low power dc and high performance ac measurement modules.

The AD7768-1 achieves the optimum balance of dc and ac performance with excellent power efficiency. The following three operating modes allow the user to trade off the input bandwidth vs. power budgets:

• Fast mode offers both a sinc filter with up to 256 kSPS and 52.2 kHz of bandwidth, and 26.4 mW of power consumption, or a FIR filter with up to 256 kSPS, 110.8 kHz of bandwidth and 36.8 mW of power consumption.
• Median mode offers a FIR filter with up to 128 kSPS, 55.4 kHz of bandwidth and 19.7 mW of power consumption.
• Low power mode offers a FIR filter with up to 32 kSPS, 13.85 kHz of bandwidth and 6.75 mW of power consumption.

The AD7768-1 offers extensive digital filtering capabilities that meet a wide range of system requirements. The filter options allow configuration for frequency domain measurements with tight gain error over frequency, linear phase response requirements (brick wall filter), a low latency path (sinc5 or sinc3) for use in control loop applications, and measuring dc inputs with the ability to configure the sinc3 filter to reject the line frequency of either 50 Hz or 60 Hz. All filters offer programmable decimation.

A 1.024 MHz sinc5 filter path exists for users seeking an even higher ODR than is achievable using the low ripple FIR filter. This path is quantization noise limited. Therefore, it is best suited for customers requiring minimum latency for control loops or implementing custom digital filtering on an external field programmable gate array (FPGA) or digital signal processor (DSP).

The filter options include the following:

• A low ripple FIR filter with a ±0.005 dB pass-band ripple to 102.4 kHz.
• A low latency sinc5 filter with up to a 1.024 MHz data rate to maximize control loop responsiveness.
• A low latency sinc3 filter that is fully programmable, with 50 Hz/60 Hz rejection capabilities.

When using the AD7768-1, embedded analog functionality within the AD7768-1 greatly reduces the design burden over the entire application range. The precharge buffer on each analog input decreases the analog input current compared to competing products, simplifying the task of an external amplifier to drive the analog input.

A full buffer input on the reference reduces the input current, providing a high impedance input for the external reference device or in buffering any reference sense resistor scenarios used in ratiometric measurements.

The device operates with a 5.0 V AVDD1 − AVSS supply, a 2.0 V to 5.0 V AVDD2 − AVSS supply, and a 1.8 V to 3.3 V IOVDD − DGND supply.

In low power mode, the AVDD1, AVDD2, and IOVDD supplies can run from a single 3.0 V rail.

The device requires an external reference. The absolute input reference (REF_IN) voltage range is 1 V to AVDD1 − AVSS.

The specified operating temperature range is −40°C to +125°C. The device is housed in a 4 mm × 5 mm, 28-lead LFCSP.

Note that, throughout this data sheet, multifunction pins, such as XTAL2/MCLK, are referred to either by the entire pin name or by a single function of the pin, for example, MCLK, when only that function is relevant.

Applications

• Platform ADC to serve a superset of measurements and sensor types
  • Sound and vibration, acoustic, and material science research and development
  • Control and hardware in loop verification
  • Condition monitoring for predictive maintenance
  • Electrical test and measurement
  • Audio testing and current and voltage measurement
  • Clinical electroencephalogram (EEG), electromyogram (EMG), and electrocardiogram (ECG) vital signs monitoring
  • USB-, PXI-, and Ethernet-based modular DAQ
  • Channel to channel isolated modular DAQ designs

The analog output ADXL356 and the digital output ADXL357 are low noise density, low 0 g offset drift, low power, 3-axis accelerometers with selectable measurement ranges. The ADXL356B supports the ±10 g and ±20 g ranges, the ADXL356C supports the ±10 g and ±40 g ranges, and the ADXL357 supports the ±10 g, ±20 g, and ±40 g ranges.

The ADXL356/ADXL357 offer industry leading noise, minimal offset drift over temperature, and long-term stability, enabling precision applications with minimal calibration.

The low drift, low noise, and low power ADXL357 enables accurate tilt measurement in an environment with high vibration. The low noise of the ADXL356 over higher frequencies is ideal for condition-based monitoring and other vibration sensing applications.

The ADXL357 multifunction pin names may be referenced only by their relevant function for either the serial peripheral interface (SPI) or limited I²C interface.

• Inertial measurement units (IMUs)/altitude and heading reference systems (AHRSs)
• Platform stabilization systems
• Structural health monitoring
• Seismic imaging
• Tilt sensing
• Robotics
• Condition monitoring

The ADXL317 is a small, thin, low latency, 3-axis accelerometer with high resolution (14-bit) measurement up to ±16 g. Digital output data is formatted as an I²S/time-division multiplexing (TDM) signal. Additionally, an I²C digital interface is provided for user configuration.

The ADXL317 is well suited for wideband active noise control (ANC) applications. Featuring very low latency from the moment of acceleration to the transmission of digital output data, the ADXL317 is uniquely capable of responding quickly enough to allow wideband ANC systems sufficient time to respond to noise scenarios. The low noise of the ADXL317 enhances the ability of the device to accurately discriminate various external noise sources. 

Due to the wide operating temperature range and high performance, the ADXL317 is ideal for other wheel well applications, such as adaptive suspension control. The Automotive Audio Bus (A²B^®) developed by Analog Devices, Inc., introduces system wide savings in cabling costs. The ADXL317 is designed to interface directly with the A²B product portfolio, such as the AD2428W and AD2425W A²B transceivers.

The ADXL317 is supplied in a small, thin, 5 mm × 5 mm × 1.45 mm, 32-pin LFCSP package. The device is qualified for use in automotive applications over the entire operating temperature range of –40°C to +125°C. 

Note that throughout this data sheet, multifunction pins, such as DTX1/TPC, are referred to either by the entire pin name or by a single function of the pin, for example, DTX1, when only that function is relevant. 

Applications

• Wideband ANC
• Adaptive suspension control 

The AD7685 is a 16-bit, charge redistribution successive approximation, analog-to-digital converter (ADC) that operates from a single power supply, V_DD, between 2.3 V to 5.5 V. It contains a low power, high speed, 16-bit sampling ADC with no missing codes, an internal conversion clock, and a versatile serial interface port. The part also contains a low noise, wide bandwidth, short aperture delay, track-and-hold circuit. On the CNV rising edge, it samples an analog input IN+ between 0 V to REF with respect to a ground sense IN−. The reference voltage, REF, is applied externally and can be set up to the supply voltage.

Power dissipation scales linearly with throughput.

The SPI-compatible serial interface also features the ability, using the SDI input, to daisy chain several ADCs on a single 3-wire bus or provides an optional BUSY indicator. It is compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic using the separate supply VIO.

The AD7685 is housed in a 10-lead MSOP or a 10-lead QFN (LFCSP) with operation specified from −40°C to +85°C.

APPLICATIONS

• Battery-powered equipment
• Medical instruments
• Mobile communications
• Personal digital assistants (PDAs)
• Data acquisition
• Instrumentation
• Process controls

The AD7134 is a quad channel, low noise, simultaneous sampling, precision analog-to-digital converter (ADC) that delivers on functionality, performance, and ease of use.

Based on the continuous time sigma-delta (CTSD) modulation scheme, the AD7134 removes the traditionally required switched capacitor circuitry sampling preceding the Σ-Δ modulator, which leads to a relaxation of the ADC input driving requirement. The CTSD architecture also inherently rejects signals around the ADC aliasing frequency band, giving the device its inherent antialiasing capability, and removes the need for a complex external antialiasing filter.

The AD7134 has four independent converter channels in parallel, each with a CTSD modulator and a digital decimation and filtering path. The AD7134 enables simultaneous sampling of four separate signal sources, each supporting a maximum input bandwidth of 391.5 kHz and achieving tight phase matching between these four signal measurements. The high level of channel integration, together with its simplified analog front-end requirement, enables the AD7134 to provide a high density multichannel data acquisition solution in a small form factor.

The signal chain simplification property of the AD7134 also improves the system level performance through the reduction of noise, error, mismatch, and distortion that is normally introduced by the analog front-end circuitry.

The AD7134 offers excellent dc and ac performance. The bandwidth of each ADC channel ranges from dc to 391.5 kHz, making the device an ideal candidate for universal precision data acquisition solutions supporting a breadth of sensor types, from temperature and pressure to vibration and shock.

The AD7134 offers a large number of features and configuration options, giving the user the flexibility to achieve the optimal balance between bandwidth, noise, accuracy, and power for a given application.

An integrated asynchronous sample rate converter (ASRC) allows the AD7134 to precisely control the decimation ratio and, in turn, the output data rate (ODR) using interpolation and resampling techniques. The AD7134 supports a wide range of ODR frequencies, from 0.01 kSPS to 1496 kSPS with less than 0.01 SPS adjustment resolution, allowing the user to granularly vary sampling speed to achieve coherent sampling. The ODR value can be controlled through the ODR_VAL_INT_x and ODR_VAL_FLT_x registers (Register 0x16 to Register 0x1C, ASRC master mode), or using an external clock source (ASRC slave mode). The ASRC slave mode operation enables synchronous sampling between multiple AD7134 devices to a single system clock. The ASRC simplifies the clock distribution requirement within a medium bandwidth data acquisition system because it no longer requires a high frequency, low jitter master clock from the digital back end to be routed to each ADC.

The ASRC acts as a digital filter and decimates the oversampled data from the Σ-Δ modulator to a lower rate to favor higher precision. The ADC data is then further processed by one of the AD7134 user-selectable digital filter profiles to further reject the out of band signals and noises, and reduce the data rate to the final desired ODR value.

The AD7134 offers three main digital filter profile options: a wideband low ripple filter with a brick wall frequency profile and an ODR range from 2.5 kSPS to 374 kSPS that is suitable for frequency domain analysis, a fast responding sinc3 filter with an ODR range from 0.01 kSPS to 1496 kSPS that is suitable for low latency time domain analysis and low frequency high dynamic range input types, and a balanced sinc6 filter with an ODR range from 2.5 kSPS to 1.496 MSPS, offering optimal noise performance and response time.

The AD7134 is also capable of performing on-board averaging between two or four of its input channels. The result is a near 3 dB, if two channels are combined, or 6 dB, if all four channels are combined, improvement in dynamic range while maintaining the bandwidth.

The AD7134 supports two device configuration schemes: serial peripheral interface (SPI) and hardware pin configuration (pin control mode). The SPI control mode offers access to all the features and configuration options available on the AD7134. SPI control mode also enables access to the on-board diagnostic features designed to enable a robust system design. Pin control mode offers the benefit of simplifying the device configuration, enabling the device to operate autonomously after power-up operating in a standalone mode.

In addition to the optional SPI, the AD7134 has a flexible and independent data interface for transmitting the ADC output data. The data interface can act as either a bus master or a slave with various clocking options to support multiple communication bus protocols. The data interface also supports daisy-chaining and an optional minimum input/output (I/O) mode designed to minimize the number of digital isolator channels required in isolated applications.

The AD7134 has an operating ambient temperature range from 0°C to 85°C. The device is housed in an 8 mm × 8 mm, 56-lead lead frame chip scale package (LFCSP).

Note that throughout this data sheet, multifunction pins, such as FORMAT1/SCLK, are referred to either by the entire pin name or by a single function of the pin, for example, SCLK, when only that function is relevant.

APPLICATIONS

• Electrical test and measurement
• Audio test
• 3-phase power quality analysis
• Control and hardware in loop verification
• Sonars
• Condition monitoring for predictive maintenance
• Acoustic and material science research and development

The ADAQ7768-1 is a 24-bit precision data acquisition (DAQ) μModule^® system that encapsulates signal conditioning, conversion, and processing blocks into one system-in-package (SiP) design for the rapid development of highly compact, high-performance precision DAQ systems.

The ADAQ7768-1 consists of:

• A low-noise, low-bias current, high-bandwidth programmablegain instrumentation amplifier (PGIA) also capable of signal amplification and signal attenuation while maintaining high input impedance.
• A fourth-order, low-noise, linear phase anti-aliasing filter.
• A low-noise, low-distortion, high-bandwidth ADC driver plus an optional linearity boost buffer.
• A high-performance medium bandwidth 24-bit Σ-Δ ADC with programmable digital filter.
• A low-noise, low-dropout linear regulator.
• Reference buffers.
• Critical passive components required for the signal chain.

The ADAQ7768-1 supports fully differential input signal with a maximum range of ±12.6 V. It has an input common-mode voltage range of ±12 V with excellent common-mode rejection ratio (CMRR).

The input signal is fully buffered with very low input bias current of 2 pA typical. This allows easy input impedance matching and enables the ADAQ7768-1 to directly interface to sensors with high output impedance.

The seven pin-configurable gain settings offer additional system dynamic range and improved signal chain noise performance with input signals of lower amplitude.

A fourth-order low-pass analog filter combined with the user-programmable digital filter ensures the signal chain is fully protected against the high frequency noise and out-of-band tones presented at the input node from aliasing back into the band of interest. The analog low-pass filter is carefully designed to achieve high phase linearity and maximum in-band magnitude response flatness. Constructed with Analog Devices’s iPASSIVES^™ technology, the resistor network used within the analog low-pass filter possesses superior resistance matching in both absolute values and overtemperature. As a result, the signal chain performance is maintained with minimum drift overtemperature and the ADAQ7768-1 has a tight phase mismatch across devices.

A high-performance ADC driver amplifier ensures the full settling of the ADC input at the maximum sampling rate. The driver circuit is designed for minimum additive noise, error, and distortion while maintaining stability. The fully differential architecture helps to maximize the signal chain dynamic range.

The analog-to-digital converter (ADC) inside the ADAQ7768-1 is a high-performance, 24-bit precision, single-channel sigma-delta converter with excellent AC performance and DC precision, and the throughput rate of 256 kSPS from a 16.384 MHz MCLK.

An optional linearity boost buffer further improves the signal chain linearity.

The ADAQ7768-1 is specified with the input reference voltage of 4.096 V, but the device can support reference voltages ranging from VDD_ADC down to 1 V.

The ADAQ7768-1 has two types of reference buffers: a precharge reference buffer to ease the reference input driving requirement or a full reference buffer to provide high impedance reference input. Both buffers are optional and can be turned off through register configuration.

ADAQ7768-1 supports three clock input types: crystal, complementary- metal-oxide-semiconductor (CMOS), or low-voltage differential signaling (LVDS).

Three types of digital low pass filters are available on the ADAQ7768-1. The wideband filter offers a filter profile similar to an ideal brick wall filter, making it ideal for frequency analysis. The sinc5 filter offers a low latency path with a smooth step response while maintaining a good level of aliasing rejection. It also supports an output data rate up to 1.024 MSPS from a 16.384 MHz MCLK, making the sinc5 filter ideal for low latency data capturing and time domain analysis. The sinc3 filter supports a wide decimation ratio and can produce output data rate down to 50 SPS from a 16.384 MHz MCLK. This, combined with the simultaneous 50Hz/ 60Hz rejection post filter, makes the sinc3 filter especially useful for precision DC measurement. All the three digital filters on the ADAQ7768-1 are FIR filters with linear phase response. The bandwidths of the filters, which directly correspond to the bandwidth of the DAQ signal chain, are fully programmable through register configuration.

The ADAQ7768-1 also supports two device configuration methods. The user has the option to choose to configure the device through register write through its SPI, or through a simple hardware pin strapping method to configure the device to operate under a number of predefined modes.

A single SPI supports both the register access and sample data readback functions. The ADAQ7768-1 always acts as a SPI target. Multiple interface modes are supported with a minimum of three IO channels required to communicate with the device.

The ADAQ7768-1 also features a suite of internal diagnostic functions to detect a broad range of errors during operation to improve the system reliability.

The ADAQ7768-1 device has an operating temperature range of −40°C to +85°C and is available in a 12.00 mm × 6.00 mm 84-ball CSP_BGA package with an 0.80 mm ball pitch, which makes it ideal for multiple channel applications. The ADAQ7768-1 uses only 75 mm² of board space, 10 times less than the discrete solution that uses 750 mm².

APPLICATIONS

• Universal input measurement platform
• Electrical test and measurement
• Sound and vibration, acoustic and material science research and development
• Control and hardware in loop verification
• Condition monitoring for predictive maintenance
• Audio test

The ADIN1110 is an ultra low power, single port, 10BASE-T1L transceiver design for industrial Ethernet applications and is compliant with the IEEE^® 802.3cg-2019^™ Ethernet standard for long reach, 10 Mbps single pair Ethernet (SPE). Featuring an integrated media access control (MAC) interface, the ADIN1110 enables direct connectivity with a variety of host controllers via a 4-wire serial peripheral interface (SPI). This SPI enables the use of lower power processors without an integrated MAC, which provides for the lowest overall system level power consumption. The SPI can be configured to use the Open Alliance SPI protocol or a generic SPI protocol.

The programmable transmit levels, external termination resistors, and independent receive and transmit pins make the ADIN1110 suited to intrinsic safety applications.

The ADIN1110 has an integrated voltage supply monitoring and power-on reset (POR) circuitry to improve system level robustness.

The ADIN1110 is available in a 40-lead, 6 mm × 6 mm lead frame chip scale package (LFCSP).

APPLICATIONS

• Field instruments
• Building automation and fire safety
• Factory automation
• Edge sensors and actuators
• Condition monitoring and machine connectivity

The LT8604/LT8604C is a compact, high speed synchronous monolithic step-down switching regulator that delivers up to 120mA to the output with high efficiency at a constant frequency, even up to 2.2MHz. It accepts a wide input voltage range up to 42V and consumes only 2.5μA of quiescent current when operating in Burst Mode. Top and bottom power switches are included with all necessary circuitry to minimize the need for external components.

The LT8604C includes BST and INTV_CC ceramic capacitors for a more compact solution while having SYNC/MODE and HYST pins. The SYNC/MODE pin selects the regulator’s operation between forced continuous mode, for predictive interference in sampling systems, Burst Mode, for increased efficiency at light loads or spread spectrum for Low EMI. It also allows synchronization to an external clock to further increase signal to noise ratio in high-resolution acquisition systems.

A PG flag signals when V_OUT is within ±7.5% of the programmed output voltage and when in fault conditions. Thermal shutdown provides additional protection.

APPLICATIONS

• Industrial Sensors
• Industrial Internet of Things
• 4mA to 20mA Current Loops
• Flow Meters
• Automotive Housekeeping Supplies

The LT8616 is a high efficiency, high speed, dual synchronous monolithic step-down switching regulator that consumes only 6.5μA of quiescent current with both channels enabled. Both channels contain all switches and necessary circuitry to minimize the need for external components. Low ripple Burst Mode operation enables high efficiency down to very low output currents while minimizing output ripple. A SYNC pin allows synchronization to an external clock. Internal compensation with peak current mode topology allows the use of small inductors and results in fast transient response and good loop stability. The enable pins have accurate 1V thresholds and can be used to program undervoltage lockout. Capacitors on the TR/SS pins programs the output voltage ramp rate during startup while the PG pins signal when each output is within 10% of the programmed output voltage. The LT8616 is available in a TSSOP package for high reliability.

Applications

• Automotive and Industrial Supplies
• General Purpose Step-Down

The LTC4332 is a point-to-point rugged SPI extender designed for operation in high noise industrial environments over long distances. Using a ±60V fault protected differential transceiver, the LTC4332 can transmit SPI data, including an interrupt signal, up to 2MHz over two twisted pair cables. The extended common mode range and high common mode rejection on the differential link provides tolerance to large ground differences between nodes.

The LTC4332 provides a control interface using a separate slave select for configuration and fault monitoring.

Applications

• Industrial Control and Sensors
• Lighting and Sound System Control

The ADM3061E/ADM3062E/ADM3063E/ADM3064E/ADM3065E/ADM3066E/ADM3067E/ADM3068E are 3.0 V to 5.5 V, IEC electrostatic discharge (ESD) protected RS-485 transceivers, allowing the devices to withstand ±12 kV contact discharges on the transceiver bus pins without latch-up or damage. The ADM3062E/ADM3064E/ADM3066E/ADM3068E feature a V_IO logic supply pin that allows a flexible digital interface capable of operating as low as 1.62 V.

The ADM3065E/ADM3066E/ADM3067E/ADM3068E are suitable for high speed, 50 Mbps, bidirectional data communication on multipoint bus transmission lines. The ADM3061E/ADM3062E/ADM3063E/ADM3064E/ADM3065E/ADM3066E/ADM3067E/ADM3068E feature a 1/4 unit load input impedance that allows up to 128 transceivers on a bus. The ADM3061E/ADM3062E/ADM3063E/ADM3064E models offer all of the same features as the ADM3065E/ADM3066E/ADM3067E/ADM3068E models at a low 500 kbps data rate that is suitable for operation over long cable runs.

The ADM3061E/ADM3062E/ADM3065E/ADM3066E are halfduplex RS-485 transceivers, fully compliant to the PROFIBUS^® standard with increased 2.1 V bus differential voltage at V_CC ≥ 4.5 V. The ADM3063E/ADM3064E/ADM3067E/ADM3068E are full duplex RS-485 transceiver options.

The RS-485 transceivers are available in a number of spacesaving packages, including the 10-lead, 3 mm × 3 mm lead frame chip-scale package (LFCSP), the 8-lead or 10-lead, 3 mm × 3 mm mini small outline package (MSOP), and the 8-lead or 14-lead, narrow body standard small outline packages (SOIC_N). Models with operating temperature ranges of −40°C to +125°C and −40°C to +85°C are available.

Excessive power dissipation caused by bus contention or by output shorting is prevented by a thermal shutdown circuit. If a significant temperature increase is detected in the internal driver circuitry during fault conditions, this feature forces the driver output into a high impedance state.

The ADM3061E/ADM3062E/ADM3063E/ADM3064E/ADM3065E/ADM3066E/ADM3067E/ADM3068E guarantee a logic high receiver output when the receiver inputs are shorted, open, or connected to a terminated transmission line with all drivers disabled.

Table 2 in the data sheet presents an overview of the ADM3061E/ADM3062E/ADM3063E/ADM3064E/ADM3065E/ADM3066E/ADM3067E/ADM3068E data rate capability across temperature, power supply, and package options. Refer to the Ordering Guide section for model numbering.

APPLICATIONS

• Industrial fieldbuses
• Process control
• Building automation
• PROFIBUS networks
• Motor control servo drives and encoders 

The serial peripheral interface (SPI) and inter-integrated circuit (I²C) interface are popular de-facto communication standards for short-distance, intra-board connectivity between a controller and external peripherals. SPI and I²C have been widely adopted by sensor, actuator, and data converter manufacturers due to widely available hardware and software support. Implementation of these interfaces is straightforward when the controller and peripheral are on the same circuit board, share a common ground plane, and are not separated by long distances ( >1 meter).

However, applications such as condition-based monitoring, factory automation, building automation, and structural monitoring, require peripherals be located remotely, typically far from the controller. System designers have traditionally extended these interfaces using repeaters or drivers with a higher drive strength at the expense of increasing the overall cost, complexity, and power consumption.

The circuit shown in Figure 1 solves the problem of long distance, robust, SPI/I²C communication simply and easily without any sacrifices to circuit component count, operating speed, or software complexity. Error free operation in high noise, harsh industrial environments requires tolerance to large ground potential differences. The SPI/ I²C extenders feature robust transceivers, which operate over an extended common mode range of ±25 V (for SPI communication) and ±15 V (for I²C communication) for distances up to 1200 meters. Each link consists of a single device at either end of the cable, capable of being powered from 3 V to 5.5 V, while a separate logic supply allows the I²C or SPI interface to operate from 1.62 V to 5.5 V. The extenders also provide an internal control interface for fault monitoring, which is critically important when monitoring equipment over long distances.

Condition-based monitoring (CbM) is one form of predictive maintenance that uses sensors to assess status of equipment overtime while the equipment is operating. The collected sensor data can establish baseline trends, such as, diagnose or even predict failure. Utilizing CbM, maintenance is performed when needed as opposed to the conventional periodic preventive maintenance model, saving both time and money.

Vibration monitoring is a common type of CbM measurement because changes in vibration trends are potentially indicative of wear or other failure modes. To measure vibration data, high bandwidth (10 kHz and more), ultralow noise (100 µg/√Hz or lower) piezoelectric sensors were historically used to satisfy these requirements. The established sensor interface for piezo sensors is integrated electronics piezoelectric (IEPE), as a result, IEPE has become a de facto interface in CbM vibration ecosystem.

With recent advancements in the microtechnology processes and fabrication techniques, MEMS accelerometers have caught up with piezoelectric sensors low noise levels and supersede in other many specifications, such as dc to low frequency response, thermal stability, shock resistance and recovery, and cost. The output of MEMS sensors, however, are either conventional 3-wire analog (ground, power, and signal) or digital if integrated with an ADC. Neither output are directly compatible with IEPE, the preferred CbM industry sensor interface.

This reference design enables a direct piezoelectric sensor IEPE replacement with benefits of high bandwidth, ultralow noise MEMS accelerometers. This circuit allows customers to easily evaluate a MEMS accelerometer for CbM applications.

Condition-based monitoring (CbM) is one form of predictive maintenance that uses various sensors to assess the operating status of equipment over time. The collected sensor data is used to establish baseline trends, which then help diagnose or even predict failure. Utilizing CbM, maintenance is performed when needed as opposed to the conventional periodic preventive maintenance model, saving both time and cost.

Vibration monitoring is a common type of CbM measurement. Changes in vibration trends are often indicative of wear or other failure modes. To measure vibration data, high bandwidth (10 kHz and more), ultralow noise (100 μg/√Hz or lower) MEMS accelerometers are a cost effective and reliable choice.

While some applications place the accelerometer close to the supporting circuitry (either on the same board or off board through a short cable), others require the accelerometer to be some distance away, which limits connectivity options. MEMS accelerometer outputs are typically analog voltage and/or digital (typically, serial peripheral interface (SPI) or I²C), none of which are well suited to driving long cables. It is possible to convert to a high speed digital interface such as USB, low voltage digital signaling (LVDS), or Ethernet. However, the additional power, size, and cost are not practical.

In contrast, analog current loop data transmission, such as the 4 mA to 20 mA industry standard, offers good noise immunity, robustness in electromagnetic interference (EMI) prone environments, high bandwidth, and up to a 20 meter long wire data transmission, all while keeping the number of devices in the circuit board to a few components. Furthermore, the 4 mA to 20 mA signaling standard is supported by nearly all legacy industrial data acquisition (DAQ) systems and can be adapted simply to the modern, Industry 4.0 smart sensor node.

The reference design shown in Figure 1 shows a high resolution, wide bandwidth, high dynamic range, Integrated Electronics Piezoelectric (IEPE)-compatible interface data acquisition (DAQ) system that interfaces with IC Piezoelectric (ICP^®)/IEPE sensors. The most common IEPE sensors are usually found in applications measuring vibration, but there are many IEPE sensors that measure parameters such as temperature, strain, shock, and displacement.

The focus of this circuit note is on the application of this solution to vibration applications, especially in the area of condition-based monitoring, but there is a large set of applications in instrumentation and industrial automation that use IEPE sensors in a similar way and that are served by similar signal chains.

Condition-based monitoring, in particular, uses sensor information to help predict changes in the condition of a machine. There are many methods of tracking the condition of a machine, but vibration analysis is the most commonly used method. By tracking the vibration analysis data over time, a fault or failure can be predicted, along with the source of the fault.

Vibration sensing in an industrial environment adds additional challenges because of the need for robust and reliable sensing methods. Knowing the condition of a machine helps increase efficiency and productivity and creates a safer working environment.

Most solutions that interface with piezoelectric sensors in the market are ac-coupled, lacking dc and subhertz measurement capabilities. The CN-0540 reference design is a dc-coupled solution in which dc and subhertz precision are achieved.

By looking at the complete data set from an IEPE vibration sensor in the frequency domain (dc to 50 kHz), the type and source of a machine fault can be better predicted using the position, amplitude, and number of harmonics found in the fast Fourier transform (FFT) spectrum.

The data acquisition board is an Arduino-compatible form factor that can be interfaced and powered directly from most Arduino-compatible development boards.

Machine condition-based monitoring (CbM) by means of vibration sensing is growing in importance in industrial applications. Companies are seeking to optimize machinery lifetime and performance and to reduce the cost of ownership, while some are looking to develop new business models around the provision of such information. To provide an accurate representation of machinery that needs monitoring, large datasets must be collected to determine a baseline operating point for the equipment in both normal operating modes and failure conditions. Once this data is collected, an algorithm or threshold detection routine can be created to provide the correct analysis for this equipment.

CbM requires capturing full bandwidth data to ensure that all harmonics, aliasing, and other mechanical interactions in both the time and frequency domain are accounted for. This data collection requires a high performance sensor and data acquisition (DAQ) system that can provide high fidelity, real-time data into a data analysis tool or application.

Using established tools like MATLAB^® or newer Python-based tools like Tensorflow, analyzing the data, profiling the machinery, and creating algorithms for smart decision making is greatly simplified.

Vibration sensing has traditionally dominated most CbM applications because of the availability of sensors, and the science behind the analysis is better understood. The integrated electronic piezoelectric (IEPE) standard is a popular signaling interface standard for high end microelectronic mechanical systems (MEMS) and piezo sensors that are prevalent in the industry today.