AD4129-4

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

FEATURES ►Ultra-lowcurrentconsumption(typical) ►32μA:continuousconversionmode(gain=128) ►5μA:dutycyclingmode(ratio=1/16) ►0.5μA:standbymode ►0.1μA:power-downmode ►Built-infeaturesforsystemlevelpowersavings ►Currentsavingdutycycleratio:1/4or1/16 ►

AD4129-4

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

FEATURES ►Ultra-lowcurrentconsumption(typical) ►32μA:continuousconversionmode(gain=128) ►5μA:dutycyclingmode(ratio=1/16) ►0.5μA:standbymode ►0.1μA:power-downmode ►Built-infeaturesforsystemlevelpowersavings ►Currentsavingdutycycleratio:1/4or1/16 ►

AD4129-4

32 μA, Ultra-Low Power, 16-Bit Sigma-Delta ADC with Integrated PGA and FIFO; Ultra-low current consumption (typical)\n 32 μA: continuous conversion mode (gain = 128)\n 5 μA: duty cycling mode (ratio = 1/16)\n 0.5 μA: standby mode\n 0.1 μA: power-down mode\nBuilt-in features for system level power savings\n Current saving duty cycle ratio: 1/4 or 1/16\n Smart sequencer and per channel configuration minimizes host processor load\n Deep embedded FIFO minimizes host processor load (depth of 256 samples)\nAutonomous FIFO interrupt functionality, threshold detection\n Single supply as low as 1.71 V increasing battery length\n RMS noise: 25 nV rms at 1.17 SPS (gain = 128) – 48 nV/√Hz\n Up to 16 noise free bits (gain = 1)\nOutput data rate: 1.17 SPS to 2.4 kSPS\n Operates from 1.71 V to 3.6 V single supply or ±1.8 V split supplies\n Band gap reference with 15 ppm/°C maximum drift\n\nPGA with rail-to-rail analog input\n Adaptable sensor interfacing functionality\n Matched programmable excitation currents for RTDs\n On-chip bias voltage generator for thermocouples\n Low-side power switch for bridge transducers\n Sensor open-wire detection\n Internal temperature sensor and oscillator\n Self and system calibration\n Flexible filter options\nSimultaneous 50 Hz/60 Hz rejection (on selected filter options)\n General-purpose outputs\n Diagnostic functionality\nCrosspoint multiplexed inputs\n 4 differential/8 pseudodifferential inputs\n 5 MHz SPI (3-wire or 4-wire)\n Available in 32-lead, 5 mm × 5 mm LFCSP\n Temperature range: −40°C to +125°C (LFCSP)\n AD4129-4 LFCSP pin compatible with AD7124-4 LFCSP;

The AD4129-4 is an ultra-low power, high precision, and measurementsolution for low bandwidth battery-operated applications. Thefully integrated analog front end (AFE) includes a multiplexer forup to 8 single-ended or 4 differential inputs, programmable gainamplifier (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-operatedlifetime (more than 5 years on a coin cell), that is, a first in, first out(FIFO) buffer and duty cycling.\n\nThe AD4129-4 allows users to measure low-frequency signalswith a current consumption of 28.5 μA (gain = 1) and 32.5 μA(gain = 128) while continuously converting, and even lower averagecurrents when using one of the duty cycling options. The AD4129-4can be configured to have 4 differential inputs or 8 single-ended orpseudodifferential inputs, which connect to a crosspoint multiplexer,where any input pair can become a measurement channel input tothe PGA and ADC.\n\nThe AD4129-4 is designed to allow the user to operate from asingle analog supply voltage from 1.71 V to 3.6 V. In batteryapplications, operation as low as 1.71 V can extend the systemlifetime as the AFE can continue its operation, even as the batteryvoltage dissipates. The digital supply can be separate and rangefrom 1.65 V to 3.6 V.\n\nTogether with the reduced current consumption, the integration ofan on-chip FIFO buffer can be used in tandem with the smartsequencer, to enable the AD4129-4 to become an autonomousmeasurement system, which allows the microcontroller to sleep forextended periods.\n\nIntelligent interrupt functionality gives the user a greater confidencein both error detection and safety. The user can enable an interruptsignal to trigger when the samples in the FIFO reach a predefinedvalue or when a user-programmable threshold is exceeded.\n\nThe following key analog functions are offered on the AD4129-4to allow simple and effective connection to transducers used formeasuring temperature, load, and pressure:\n\n\nPGA. Due to the programmable gain (from 1 to 128) and thehigh input impedance with low input current, the PGA allowsdirect interfacing to transducers with low output amplitudes suchas resistive bridges, thermocouples, and resistance temperaturedetectors (RTDs).\n The capacitive PGA allows full common-mode input range, givingdesigners greater margin for widely varying input commonmodes. A wider common-mode input range improves the overallresolution and is highly effective in ratio metric measurements.\n Low drift precision current sources. The IEXC0 and IEXC1 currentsources can be used 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.\n The low-side power switch (PDSW) can be used to power downbridge sensors between conversions. The PDSW can be controlledwithin the sequencer on a per channel basis, allowingoptimum timing and energy savings in the overall system. ThePDSW can also allow higher powered analog sensors to be usedin a low power system.\n Voltage bias for thermocouples (the VBIAS source sets thecommon-mode voltage of a channel to AVDD/2).\n The smart sequencer allows the conversion of each enabledpreconfigured channel in a predetermined order, allowing a mixof transducer, system checks, and diagnostic measurements tobe interleaved. The sequencer eliminates the need for repetitiveserial interface communication with the device. Sixteen channelscan be configured in the sequence, each of them selecting fromeight predefined ADC setups that allow selection of gain, filtertype, output data rate, buffering, timing, and reference source.\nHigh levels of integrated front-end functionality, coupled with smallpackage options, allow smaller end solutions. For example, theAD4129-4 integrates a low thermal drift band gap reference inaddition to accepting an external differential reference, which canbe internally buffered.In safety critical applications, the AD4129-4 includes diagnosticfunctionality such as open-wire detection through burnout currents,internal temperature sensor, reference detection, and analog inputovervoltage and undervoltage detection. Added diagnostics areincluded on the digital interface such as cyclic redundancy check(CRC) and serial interface checks for a robust communication link.

AD4129-4_V01

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

FEATURES ►Ultra-lowcurrentconsumption(typical) ►32μA:continuousconversionmode(gain=128) ►5μA:dutycyclingmode(ratio=1/16) ►0.5μA:standbymode ►0.1μA:power-downmode ►Built-infeaturesforsystemlevelpowersavings ►Currentsavingdutycycleratio:1/4or1/16 ►

AD4129-4BCBZ-RL7

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

FEATURES ►Ultra-lowcurrentconsumption(typical) ►32μA:continuousconversionmode(gain=128) ►5μA:dutycyclingmode(ratio=1/16) ►0.5μA:standbymode ►0.1μA:power-downmode ►Built-infeaturesforsystemlevelpowersavings ►Currentsavingdutycycleratio:1/4or1/16 ►

AD4129-4BCPZ-RL7

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

FEATURES ►Ultra-lowcurrentconsumption(typical) ►32μA:continuousconversionmode(gain=128) ►5μA:dutycyclingmode(ratio=1/16) ►0.5μA:standbymode ►0.1μA:power-downmode ►Built-infeaturesforsystemlevelpowersavings ►Currentsavingdutycycleratio:1/4or1/16 ►

AD4129-4BCPZ-RL7

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

FEATURES ►Ultra-lowcurrentconsumption(typical) ►32μA:continuousconversionmode(gain=128) ►5μA:dutycyclingmode(ratio=1/16) ►0.5μA:standbymode ►0.1μA:power-downmode ►Built-infeaturesforsystemlevelpowersavings ►Currentsavingdutycycleratio:1/4or1/16 ►