32 μA, Ultra Low Power, 16-Bit Sigma-Delta ADC with Integrated PGA and FIFO

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Part Details
Part Models 1
1ku List Price Starting From $5.63
  • Ultra-low current consumption (typical):
    • 32 μA: continuous conversion mode (gain = 128)
    • 5 μA: duty cycling mode (ratio = 1/16)
    • 0.5 μA: standby mode
    • 0.1 μA: power-down mode
  • Built-in features for system level power savings:
    • Current saving duty cycle ratio: 1/4 or 1/16
    • Smart sequencer and per channel configuration minimizes host processor load
    • Deep embedded FIFO minimizes host processor load (depth of 256 samples)
    • Autonomous FIFO interrupt functionality, threshold detection
    • Single supply as low as 1.71 V increasing battery length
  • RMS noise: 25 nV rms at 1.17 SPS (gain = 128) to 48 nV/√Hz
  • Up to 22 noise free bits (gain = 1)
  • Output data rate: 1.17 SPS to 2.4 kSPS
  • Operates from 1.71 V to 3.6 V single supply or ±1.8 V split supplies
  • Band gap reference with 15 ppm/°C maximum drift
  • PGA with rail-to-rail analog input
  • Adaptable sensor interfacing functionality:
    • Matched programmable excitation currents for (RTDs)
    • On-chip bias voltage generator for thermocouples
    • Low-side power switch for bridge transducers
    • Sensor open wire detection
  • Internal temperature sensor and oscillator
  • Self and system calibration
  • Flexible filter options
  • Simultaneous 50 Hz/60 Hz rejection (on selected filter options)
  • General-purpose outputs
  • Diagnostic functionality
  • Crosspoint multiplexed inputs
    • 8 differential/16 pseudodifferential inputs
  • 5 MHz SPI (3-wire or 4-wire)
  • Available in 35-ball, 2.74 mm × 3.6 mm WLCSP
  • Temperature range: −40°C to +105°C
Additional Details
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The AD4129-8 is an ultra-low power, high precision, measurement solution for low bandwidth battery operated applications. The fully integrated analog front end (AFE) includes a multiplexer for up to 16 single-ended or eight differential inputs, programmable gain amplifier (PGA), 16-bit sigma-delta (Σ-Δ) analog-to-digital converter (ADC), on-chip reference and oscillator, selectable filter options, smart sequencer, sensor biasing and excitation options, diagnostics, and newly added features to improve the battery-operated lifetime (more than five years on a coin cell), i.e., a first in, first out (FIFO) buffer and duty cycling.

The AD4129-8 allows to measure low frequency signals with a current consumption of 28.5 μA (gain = 1) and 32.5 μA (gain = 128) while continuously converting, and even lower average currents when using one of the duty cycling options. Configure the AD4129-8 to have eight differential inputs or 16 single-ended or pseudodifferential inputs, which connect to a crosspoint multiplexer, where any input pair can become a measurement channel input to the PGA and ADC.

The AD4129-8 is designed to operate from a single analog supply voltage from 1.71 V to 3.6 V. In battery applications, operation as low as 1.71 V can extend the system lifetime as the AFE can continue its operation, even as the battery voltage dissipates. The digital supply can be separate and range from 1.65 V to 3.6 V. Together with the reduced current consumption, use the integration of an on-chip FIFO buffer in tandem with the smart sequencer, to enable the AD4129-8 to become an autonomous measurement system, which allows the microcontroller to sleep for extended periods.

Intelligent interrupt functionality gives greater confidence in both error detection and safety. Enable an interrupt signal to trigger when the samples in the FIFO reach a predefined value or when a user programmable threshold is exceeded.

The AD4129-8 offers the following key analog functions to allow simple and effective connection to transducers used for measuring temperature, load, and pressure:

  • PGA. Due to the programmable gain (from 1 to 128) and the high input impedance with low input current, the PGA allows direct interfacing to transducers with low output amplitudes like resistive bridges, thermocouples, and resistance temperature detectors (RTDs).
  • The capacitive PGA allows full common-mode input range, giving designers greater margin to widely vary input common modes. A wider common-mode input range improves the overall resolution and is highly effective in ratiometric measurements.
  • Low drift precision current sources. Use the IEXC0 and IEXC1 current source to excite 2‑, 3‑, and 4‑wire RTDs. Excitation current output options include 100 nA, 10 μA, 20 μA, 50 μA, 100 μA, 150 μA, and 200 μA.
  • Use the low-side power switch (PDSW) to power down bridge sensors between conversions. Control the PDSW within the sequencer on a per channel basis, allowing optimum timing and energy savings in the overall system. The PDSW can also allow higher powered analog sensors to be used in a low power system.
  • Voltage bias for thermocouples (the VBIAS source sets the common-mode voltage of a channel to AVDD/2).
  • The smart sequencer allows the conversion of each enabled
    preconfigured channel in a predetermined order, allowing a mix of transducer, system checks, and diagnostic measurements to be interleaved. The sequencer eliminates the need for repetitive serial interface communication with the device. Configure sixteen channels in the sequence, each of them selecting from eight predefined ADC setups that allow the selection of gain, filter type, output data rate, buffering, timing, and reference source. High levels of integrated front-end functionality coupled with small package options allow smaller end solutions. For example, the AD4129-8 integrates a low thermal drift band gap reference in addition to accepting an external differential reference, which can be internally buffered.

In safety critical applications, the AD4129-8 includes diagnostic functionality such as open wire detection through burnout currents, internal temperature sensor, reference detection, and analog input overvoltage and undervoltage detection. The digital interface has added diagnostics like cyclic redundancy check (CRC) and serial interface checks for a robust communication link.


  • Smart transmitters
  • Wireless battery and harvester powered sensor nodes
  • Portable instrumentation
  • Temperature measurement: thermocouple, RTD, thermistors
  • Pressure measurement: bridge transducers
  • Healthcare and wearables
Part Models 1
1ku List Price Starting From $5.63

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Evaluation Kit

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Evaluation Board for the AD4129-8, 8-Channel, Ultra-Low Power, 16-Bit Sigma-Delta ADC with Integrated Front End and FIFO



Evaluation Board for the AD4129-8, 8-Channel, Ultra-Low Power, 16-Bit Sigma-Delta ADC with Integrated Front End and FIFO

Evaluation Board for the AD4129-8, 8-Channel, Ultra-Low Power, 16-Bit Sigma-Delta ADC with Integrated Front End and FIFO

Features and Benefits

  • Full featured evaluation board for the AD4129-8
  • PC control in conjunction with Analog Devices, Inc. System Demonstration Platform (EVAL-SDP-CK1Z)
  • PC software for control and data analysis (time domain)
  • Standalone capability

Product Detail

The EVAL-AD4129-8WARDZ evaluation kit features the AD4129-8 16-bit, ultra-low power, low noise analog-to-digital converter (ADC).

The EVAL-AD4129-8WARDZ board connects to the USB port of the PC by connecting to the EVAL-SDP-CK1Z motherboard. Regulate a 5 V USB supply through the PC to 3.3 V to supply the AD4129-8 and support all necessary components.

The AD4129-8 ACE Plugin fully configures the AD4129-8 device register functionality and provides DC time domain analysis as waveform graphs, histograms, and associated noise analysis for ADC performance evaluation.

The EVAL-AD4129-8WARDZ is an evaluation board that evaluates the features of the ADC. The user PC software executable controls the AD4129-8 over the USB through the EVAL-SDP-CK1Z System Demonstration Platform (SDP) board.

The product data sheet provides the full specifications of the AD4129-8. Consult the AD4129-8 data sheet in conjunction with this user guide when working with the EVAL-AD4129-8WARDZ evaluation board.

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