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Engineer-to-Engineer Application Notes

Application notes that were published within the past 12 months.

November 2015

AN-1026: High Speed Differential ADC Driver Design Considerations

Though ADCs with differential inputs can accept single-ended input signals, optimum ADC performance is achieved when the input signal is differential. This application note addresses the design considerations around ADC drivers—circuits often specifically designed to provide such differential signals—that perform many additional important functions, including amplitude scaling, single-ended to differential conversion, buffering, common-mode offset adjustment, and filtering.

AN-1370: Design Implementation of the ADF7242 Pmod Evaluation Board Using the Johanson Technology, Inc., 2450AT18A100 Chip Antenna

This application note describes the use and design implementation of the EVAL-ADF7242-PMDZ, a 2.4 GHz wireless transceiver peripheral module (Pmod™) evaluation board that uses an ADF7242 transceiver in conjunction with a Johanson 2450AT18A100 chip antenna. The chip antenna makes the ADF7242 evaluation board more compact, more cost effective, and easier to use.

October 2015

AN1382: ADP1055 EEPROM Programming

The ADP1055 digital controller for power supply applications with PMBus interface offers a register map and an EEPROM that are programmed with settings for a specific application. This application note focuses on the software procedure to program the ADP1055.

AN 1373: ADA4530-1 Femtoampere Level Input Bias Current Measurement

The ADA4530-1 is a single, electrometer grade operational amplifier with a femtoampere (10−15) level input bias current (IB) and an ultralow offset voltage. This application note highlights several different methods for measuring the ADA4530-1 femtoampere level input bias current feature in the SOIC package using the ADA4530-1R-EBZ-TIA or the ADA4530-1R-EBZ-BUF evaluation board.

AN1344: High Common-Mode Voltage Current Loop Transmitter Front End

The current loop is a common signaling technique for sending and receiving sensor data over long distances. This application note highlights the AD8479 serving as a front end for a current loop transmitter that enables the transmitter to operate in applications with very high CMV, such as motor controls and high voltage current sensing.

AN1308: Common-Mode Step Response of Current Sense Amplifiers

Current sense amplifiers are one of the specialty amplifiers from Analog Devices, Inc., used to amplify small differential signals in the presence of large common-mode voltages. A typical application for a current sense amplifier is amplifying the voltage across a shunt resistor. This application note details how to set-up for, and measure the current-mode step response of ADI’s current sense amplifier portfolio.

September 2015

AN1377: Gain and Offset Temperature Drift Compensation for the AD7403/AD7405

The AD7403/AD7405 are high performance, second-order, Σ-Δ modulators that convert an analog input signal into a high speed, single-bit data stream, with on-chip digital isolation based on Analog Devices. Inc., iCoupler® technology. This application note describes a method of using a collocated, system integrated, temperature sensor with the AD7403/AD7405 devices to calibrate out a large degree of offset and gain error drift over temperature.

AN1371: Variable Dynamic Range

Variable dynamic range (VDR) provides an efficient, non- obstructive technique to provide wideband, high resolution, and fast sample rate to digital predistortion (DPD) observation receivers. In this application, nonlinearities are measured and digitally corrected such that overall intermodulation performance is significantly better than that of the core signal chain while at the same time boosting amplifier efficiency.

AN-1367: I2C Interface Between the ADE7953 and the ADuCM360

This application note demonstrates the implementation of an I2C interface between the ADE7953 (the slave) and the ADuCM360 (the master), using C programming language. The ADE7953 is a single-phase energy metering IC, and the ADuCM360 is an ARM® Cortex®-M3-based microcontroller.

AN-1374: ADE7912/ADE7913 Front-End DSP Specifications

This application note explains several aspects of the digital filtering associated with the Σ-Δ modulators used in the ADE7912/ADE7913. The role of the filters is to decimate the outputs of the modulators to various rates, while eliminating high frequency noise. These rates start from a high of 8 kHz and go as low as 1 kHz, allowing the user to update the rates to the microcontroller processing bandwidth.

AN-1365: AD1933/AD1934/AD1938/AD1939/AD1974 Boot Up Application

The AD1933/AD1934/AD1938/AD1939/AD1974 family of codecs, ADCs, and DACs have a standalone mode of operation that allows them to be used without a microcontroller. This application note details a low cost solution for booting up these parts in any desired mode of operation. For this example, a Microchip® PIC12(L)F1571/PIC12(L)F1572 is used to boot up the AD1938 and also provides for a mute function. This part is very low cost and is available through normal distribution channels. It is offered in a variety of packages to meet the cost/size needs of most applications.

AN-1250: Interfacing an ADT7310/ADT7410 to a Cortex-M3 Based Precision Analog Microcontroller (ADuCM360)

This application note describes how to connect evaluation boards and how to easily start collecting high accuracy, digital temperature readings from the ADT7310 and ADT7410 sensors using the Cortex-M3® based precision Analog Devices Inc., microcontrollers, such as the ADuCM360.

August 2015

AN1366: Using the ADP5070/ADP5071 to Create Positive and Negative Voltage Rails when VOUT < VIN

This application note provides appropriate design formulas and considerations for designing the ADP5070/ADP5071 in one of the least understood, yet most commonly used, dc-to-dc converter topologies, the SEPIC configuration.

AN1368: Ferrite Bead Demystified< VIN

This application note discusses the important considerations that system designers need to be aware of when using ferrite beads in power supply systems, including response characteristics of the ferrite bead, a simplified ferrite bead model and simulation, dc current considerations, LC resonance effects, and damping methods.

July 2015

AN-1349: PCB Implementation Guidelines to Minimize Radiated Emissions on the ADM2582E/ADM2587E RS-485/RS-422 Transceivers

This application note examines specific layout options and component selection to achieve radiated emissions standards EN55022/CISPR22 Class A (FCC Class A) emissions standards commonly used in industrial environments, and EN55022/CISPR22 Class B (FCC Class B) standards in an unshielded environment, for the ADM2582E/ADM2587E RS-485/RS-422 transceivers.

AN-1364 Differential Filter Design for a Receive Chain in Communication Systems

This application note looks at some basic filter key specifications concepts, a few types of frequently used filter responses, a Chebyshev Type 1 filter application, and step-by-step instructions on how to transfer a single-ended filter design to a differential filter design. A differential filter design example is in this application note as well as a few points on how to optimize differential circuit PCB design.

June 2015

AN1352: Calibration Procedures for the ADA4571

The ADA4571 is an analog anisotropic magnetoresistive (AMR) angle sensor consisting of a sensing element and a conditioning analog instrumentation amplifier. This application note discusses various simple calibration procedures to reduce the angle linearity error from the device.

April 2015

AN-1340: ADF7023-J IEEE 802.15.4g/UBUSAir/FAN Firmware Module

This application note describes the IEEE 802.15.4g (15d4g) firmware download module for the ADF7023-J transceiver IC. The firmware module adds the following features: IEEE 802.15.4g physical layer header formatting and data whitening, transmitter/receiver rolling data buffer, 4‑byte to 1000-byte preamble, and ARIB STD T108 compliant clear channel assessment. The ADF7023-J low power, 902 MHz to 958 MHz transceiver contains a custom microcontroller core with mask ROM that implements packet handling functions and translates radio commands into internal control sequences. An additional 2 kB of program RAM is available and serves as program code memory, which enables the radio controller commands that provide modified or extended functionality. The IEEE 802.15.4g firmware download module described in this application note is based on program code downloaded into the program RAM.

March 2015

AN-1339: ADF7023-J AD_15d4g Firmware Download Module

This application note describes the AD_15d4g firmware download module for the ADF7023-J transceiver IC. This firmware download module adds the following features to the ADF7023-J: IEEE 802.15.4g physical layer (PHY) header formatting, IEEE 802.15.4g data whitening, Tx/Rx rolling data buffer, 1 byte to 1000 byte Tx preamble, ARIB STD T108 clear channel assessment (CCA), and Rx antenna diversity.

AN-1318: Differential Overvoltage Protection Circuits for Current Sense Amplifiers

Most current sense amplifiers are capable of handling high common-mode voltages (CMVs) but not high differential input voltages. In certain applications, there are fault conditions wherein the differential input voltage at the shunt exceeds the specified maximum voltage of the amplifier. These conditions can cause damage to the amplifier. This application note introduces two basic overvoltage protection circuits for current sense amplifiers and discusses the effects of the circuits on device performance for two types of current sense architectures—a current sense amplifier (using the AD8210 as an example) and a difference amplifier (using the AD8418 as an example).

January 2015

AN-1347: Operating the ADF4360-7 at High PFD Frequencies

The ADF4360-7 is a very flexible synthesizer (phase-locked loop (PLL) with an integrated voltage controlled oscillator (VCO)) that enables the generation of frequencies from 350 MHz to 1800 MHz. An on-chip calibration engine fine tunes the output frequency after power-on. Under most operating conditions, the calibration process works well; however, timing uncertainty errors can occur, which result in tuning errors that degrade the phase noise and/or spurious performance. This application note describes how to maintain optimum performance when operating the device at a relatively high phase frequency detector (PFD) frequency.AN-1337

AN-1343: Energy Metering on Hot Swap and Power Monitor Devices

A variety of hot swap and power monitor devices, including the ADM1075, ADM1276, ADM1278, ADM1293, and ADM1294 include energy metering functionality. Each device can measure input voltage as well as output current. The 12-bit input voltage and 12-bit output current measurement values are multiplied to give the input power value. This multiplication uses fixed point arithmetic and produces a 24-bit value. The PMBus™ Application Profile for Hot Swap Controllers specifies that users can read individual power samples or use on-chip energy metering functionality. The advantage of on-chip functionality is that the host processor does not have to poll the power monitor continuously to read power samples. Individual power samples are accumulated on chip, so the user can read from the power monitor via PMBus intermittently, freeing up the I2C bus for other transactions.

AN-1342: AD9142 to AD9142A Migration

The AD9142 and AD9142A dual 16-bit high-speed digital-to-analog converters (DACs) use low-voltage differential signaling (LVDS). The AD9142A, recommended for new designs, serves wider bandwidth applications due to its higher maximum interface speed. This application note describes the differences between the two products and provides a guide for upgrading from the AD9142 to the AD9142A.

AN-1341: Using the AD8436 True RMS to DC Converter

The AD8436 complete true rms measurement system-on-a-chip comprises three independent circuit blocks. Its rail-to-rail field effect transistor (FET) input amplifier, high dynamic range, true zero rms computing core, and precision rail-to-rail output amplifier facilitate measurement systems that operate from high-impedance voltage sources in the megohm range to deliver high-accuracy dc output voltages equivalent to the rms value of applied input voltages. This 16-page Application Note explores configuration options for the AD8436.

AN-1335: Temperature Measurements on the ADE7932/ADE7933 and ADE7978 Chipset

The ADE7932/ADE7933 and the ADE7978 form a chipset for measuring 3-phase electrical energy measurement using shunts as current sensors. The ADE7932 and ADE7933 contain a temperature sensor that is measured by the ADE7978. The temperature is used to compensate the gain variation in the current channel datapath. This application note presents the factors that influence the meter performance over temperature, and how temperature measurements are used to compensate these factors and make the meter more stable with temperature.

December 2014

AN-1338: ADM1278 Design Guide

This 4-page Application Note provides a guide to the ADM1278 Hot Swap Designer Excel-based design tool, which allows a designer to enter system specifications and then compute the undervoltage threshold, overvoltage threshold, current limit, and other settings.

AN-1322: ADuCM320 Code Execution Speed

The ADuCM320 contains an ARM® Cortex®-M3 processor with integrated flash and RAM for code and data. To increase the execution speed of the central processing unit, it also includes a cache with various modes of operation. This application note presents the modes that are of interest for user applications, without covering the specific features of the ARM Cortex-M3.

AN-1319: Compensator Design for a Battery Charge/Discharge Unit Using the AD8450 or the AD8451

Most battery formation and test systems implement the CC-CV algorithm using high-accuracy feedback loops that control the battery current and voltage. To ensure high battery quality, the feedback loops need to be stable and robust. This 20-page Application Note describes how to design and implement the compensation network for the constant current and constant voltage feedback loops in a battery test or formation system using the AD8450 or AD8451 analog front-end and controller.


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