AD7902BRQZ - Dual 16-Bit 1 MSPS SAR ADC | Analog Devices
MPN: AD7902BRQZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $43.36 | $43.36 |
| 10 | $39.1 | $391.00 |
| 100 | $33.95 | $3,395.00 |
| 500 | $28.3 | $14,150.00 |
| 1,000 | $25.4 | $25,400.00 |
AD7902BRQZ Overview
An SAR ADC is a type of analog-to-digital converter that uses a binary-search successive-approximation algorithm against a precision DAC to resolve an input voltage one bit at a time per clock cycle, delivering deterministic low-latency conversions with no pipeline delay. SAR ADCs sit within the broader hierarchy of data converters -> ADC -> successive-approximation ADC -> precision mixed-signal IC -> semiconductor. They are favored in multi-channel data-acquisition systems, motor control, and instrumentation where deterministic latency and compact footprint outweigh the need for very high sampling rates.
Differentiating specifications for the AD7902 include true 16-bit no-missing-code performance, two independent sampling ADCs in one package, an external reference per ADC with the reference decoupled independently of VDDx, and a flexible 3-wire serial interface that supports daisy-chain mode for synchronized multi-channel systems. The wide VIO range (2.375V to 5.25V) simplifies interface to modern processors operating at 1.8V, 3.3V, or 5V logic without level translators. The QSOP-20 footprint measures roughly 8.65 mm x 3.90 mm with a 0.635 mm lead pitch.
Architecturally, each ADC channel pairs a switched-capacitor charge-redistribution DAC with a precision comparator and SAR logic core, providing inherent sample-and-hold behavior on the analog input pin. The reference voltage can be set independently from VDDx, allowing the user to optimize dynamic range on a per-channel basis - useful when one channel measures a low-amplitude transducer and a second measures a higher-voltage node in the same chassis.
Typical applications include industrial multi-channel data acquisition modules, motor-control current and voltage feedback, portable instrumentation and battery-powered sensor front ends, optical-module monitoring, and general-purpose precision signal conditioning in process-control PLCs. Design considerations include placing a 100 nF ceramic capacitor in close proximity to each REFx and GND pin with wide, low-impedance traces, and decoupling VDDx and VIOx with 100 nF ceramics to suppress digital switching noise coupling into the analog input.
This page synthesizes distributor pricing as of 2026-10-06, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for AD7902BRQZ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with AD7902BRQZ (same form factor and footprint) — differing in Input Type, Number of Channels, Operating Temperature Range, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7902BRQZ-RL7
✅ Drop-In📋 Reference alternative (not in catalog)
AD7266BRUZ
✅ Drop-In📋 Reference alternative (not in catalog)
AD7266BRUZ-RL7
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
ADS7851IRTET
✅ Drop-In📋 Reference alternative (not in catalog)
AD7606C-16BSTZ
✅ Drop-In✓ In Stock
$49.2188 / Unit
View Datasheet →AD7902BRQZ Maximum Ratings & Electrical Characteristics
| Resolution | 16 bit |
| Number of Channels | 2 (dual) |
| Sampling Rate | 1 MSPS |
| ADC Architecture | SAR (Successive Approximation Register) |
| Input Type | Pseudo-Differential |
| Analog Supply Voltage (VDD) | 2.375 V to 2.625 V (single 2.5 V typical) |
| Digital I/O Supply (VIO) | 2.375 V to 5.25 V |
| Power Consumption | 12.0 mW typical at 1 MSPS |
| Reference | External per ADC (REFx pin) |
| Serial Interface | SPI-compatible, 3-wire, daisy-chain capable |
| Package | 20-pin QSOP (RQ-20) |
| Package Dimensions | 8.65 mm x 3.90 mm, 0.635 mm pitch |
| Operating Temperature Range | -40 C to +85 C |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (per manufacturer product page) |
AD7902BRQZ Pin Configuration
| Pin 1 | VDD1 — Analog supply voltage for ADC 1 (2.375V to 2.625V) |
| Pin 2 | REF1 — External reference input for ADC 1 |
| Pin 3 | IN1+ — Positive analog input for ADC 1 |
| Pin 4 | IN1- — Negative analog input for ADC 1 (pseudo-differential return) |
| Pin 5 | GND1 — Analog ground for ADC 1 |
| Pin 6 | VIO — Digital I/O supply (2.375V to 5.25V) |
| Pin 7 | DGND — Digital ground |
| Pin 8 | SDI1 — SPI serial data input (daisy-chain) |
| Pin 9 | SDO2 — SPI serial data output (daisy-chain) |
| Pin 10 | SCLK — SPI serial clock |
| Pin 11 | CNV — Convert / chip-select input |
| Pin 12 | BUSY — Optional busy indicator output |
| Pin 13 | SDO1 — SPI serial data output for ADC 1 |
| Pin 14 | GND2 — Analog ground for ADC 2 |
| Pin 15 | IN2- — Negative analog input for ADC 2 (pseudo-differential return) |
| Pin 16 | IN2+ — Positive analog input for ADC 2 |
| Pin 17 | REF2 — External reference input for ADC 2 |
| Pin 18 | VDD2 — Analog supply voltage for ADC 2 (2.375V to 2.625V) |
| Pin 19 | SDI2 — SPI serial data input for ADC 2 (daisy-chain) |
| Pin 20 | SDO — Primary SPI serial data output |
Typical Applications
AD7902BRQZ is suitable for 6 applications: Industrial Multi-Channel Data Acquisition, Motor Control Current and Voltage Feedback, Portable Instrumentation and Sensor Front Ends, Optical Module Monitoring, Process Control PLC Analog Input Modules, Medical Patient Monitoring Points.
Industrial Multi-Channel Data Acquisition
The AD7902BRQZ fits industrial data acquisition systems requiring two synchronized 16-bit measurements from sensors such as strain gauges, thermocouples, or pressure transducers. Its dual pseudo-differential inputs let one channel monitor a process variable while the second monitors a reference for ratiometric compensation, both sampled at 1 MSPS with matched temperature drift. The 12 mW typical power at full speed is acceptable in PLC backplanes with adequate ventilation, while the 2.375V-5.25V VIO range allows direct hookup to 3.3V or 5V host processors. Decouple each VDDx and REFx pin with a 100 nF ceramic placed within 3 mm of the pin.
Recommended
Motor Control Current and Voltage Feedback
The AD7902BRQZ serves motor-control feedback loops by sampling phase current and DC-bus voltage through its two ADC channels with deterministic SAR latency. The 1 MSPS per-channel throughput oversamples PWM-cycle waveforms at typical 20 kHz switching frequencies, enabling sub-microsecond feedback for FOC algorithm updates. The 12 mW power draw is acceptable in industrial drives with chassis cooling, and the QSOP-20 footprint fits compact inverter PCBs. Place current-sense shunt amplifiers upstream and route analog traces away from IGBT gate-drive switching nodes.
Recommended
Portable Instrumentation and Sensor Front Ends
The AD7902BRQZ suits portable test and measurement instruments where two synchronized 16-bit analog inputs are needed in a compact QSOP-20 footprint. Battery-powered multimeters, handheld oscilloscope front-ends, and field-data loggers benefit from the 12 mW typical power consumption at 1 MSPS, scaling down to roughly 1.2 mW at 100 kSPS. The wide 2.375V-5.25V VIO range simplifies interfacing with Li-ion powered MCUs. Use a low-dropout regulator and a precision reference such as ADR4525 for stable readings across battery discharge.
Recommended
Optical Module Monitoring
The AD7902BRQZ fits SFP/QSFP optical module monitoring by sampling received optical power via a photodiode transimpedance amplifier on channel 1 and laser bias current or temperature on channel 2. The 1 MSPS per-channel rate captures fast transients during burst-mode operation, while the dual pseudo-differential inputs reject common-mode noise from the host switch-mode supply. The QSOP-20 package fits the tight thermal envelope of pluggable optics. Decouple VDDx with a 100 nF ceramic and provide a clean 2.5V analog rail.
Recommended
Process Control PLC Analog Input Modules
The AD7902BRQZ fits PLC analog input modules that read two 4-20 mA or 0-10 V process signals through their dual pseudo-differential ADC channels. The 16-bit no-missing-code performance delivers 0.0015% resolution per LSB, exceeding typical 0.1% process-control accuracy requirements, while the 1 MSPS per-channel rate supports fast loop-update applications. The 12 mW power simplifies PLC backplane thermal budgets. Use an external RC anti-alias filter on each input and route analog grounds in a star topology with digital ground.
Recommended
Medical Patient Monitoring Points
The AD7902BRQZ fits medical patient-monitoring front ends such as ECG or pulse-oximetry modules where two synchronized 16-bit measurements are required from low-amplitude biomedical electrodes. The dual ADC channels simultaneously sample two electrode pairs for differential ECG readings, while the 12 mW power is acceptable for mains-powered bedside monitors. The 16-bit resolution supports the 0.5 mV ECG signal range with 12-bit-equivalent oversampling for noise rejection. Use AD8226 instrumentation amplifiers upstream and isolate the analog ground plane.
Recommended
Recommended Products Summary
Engineering reference data for AD7902BRQZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7902BRQZ-RL7 | AD7266BRUZ | AD7266BRUZ-RL7 | ADS7851IRTET |
|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices (same) | Analog Devices (same) | Analog Devices (same) | Texas Instruments (cross-brand) |
| Package | 20-QSOP (RQ-20) | 20-QSOP (RQ-20) - same | 20-TSSOP (RU-20) - pin-compatible footprint (verify) | 20-TSSOP (RU-20) - same | 20-QFN (RT-20) - pin-compatible footprint (verify) |
| Resolution | 16 bit | 16 bit | 16 bit | 16 bit | 14 bit (vs 16 bit) |
| Sampling Rate | 1 MSPS | 1 MSPS | 2 MSPS (+100%) | 2 MSPS (+100%) | 750 kSPS (-25%) |
| Channels | 2 (dual) | 2 (dual) | 2 (dual) | 2 (dual) | 2 (dual) |
| Input Type | Pseudo-Differential | Pseudo-Differential | Pseudo-Differential | Pseudo-Differential | Pseudo-Differential |
| Analog Supply (VDDx) | 2.375V to 2.625V | 2.375V to 2.625V | 2.375V to 2.625V | 2.375V to 2.625V | 2.7V to 5.25V (verify) |
| Interface | SPI, 3-wire, daisy-chain | SPI, 3-wire, daisy-chain | SPI, 3-wire | SPI, 3-wire | SPI/parallel |
Key Differentiators
- True dual independent ADC integration in QSOP-20 (vs AD7266BRUZ)
- Wide VIO range (2.375V-5.25V) eliminates level shifters (vs ADS7851IRTET)
- Daisy-chain SPI reduces host pin count (vs ADS7851IRTET)
Design Notes
Per the AD7902 datasheet (Rev. B), place a 100 nF ceramic capacitor in close proximity to (ideally right up against) each REFx pin and each GNDx pin, then connect them with wide, low-impedance traces. Decouple the VDDx and VIOx rails with 100 nF ceramic capacitors at each pin, plus a bulk 10 uF tantalum or ceramic capacitor shared across the chip. This decoupling topology prevents digital switching noise from coupling into the reference or analog inputs and degrading effective resolution.
Use a star-ground topology with separate analog (GNDx) and digital (DGND) planes joined at a single point near the ADC. Route analog input traces (INx+, INx-) as differential pairs with matched lengths, kept short and away from switching converter or IGBT gate-drive traces. Place the input RC anti-alias network (typically 100 ohm + 1 nF) within 5 mm of each INx+ pin to filter RF interference before sampling. Estimated: at 1 MSPS the input bandwidth is 500 MHz, so the anti-alias cutoff should be set at 500 kHz or lower.
Do not tie INx- to GNDx directly if the input source is not ground-referenced - the AD7902BRQZ uses pseudo-differential inputs that require a return path within the common-mode range. Ensure VIO is present before VDDx at power-up to prevent latch-up; if the host cannot guarantee this sequence, place a small FET-based power-sequencer on the VDDx rail. Do not exceed the absolute maximum ratings of VDDx < 3V or VIOx < 6V, and verify that the reference voltage on REFx never exceeds VDDx + 0.3V.
Compliance Information
RoHS and REACH compliance per Analog Devices product page. Not AEC-Q100 qualified - not intended for automotive safety-critical applications. Lead-free (Pb-free) reflow-compatible per QSOP-20 package standard.
