Analog Devices Inc. AD7902BRQZ

Overview

AD7902BRQZ from Analog Devices is a dual 16-bit, pseudo-differential successive approximation register (SAR) ADC with simultaneous sampling capability, 1 MSPS throughput, ±2.5 LSB INL max, 91 dB SINAD at 1 kHz, and 12.0 mW total power consumption at full speed - deployed in battery-powered data acquisition and redundant measurement systems.

For engineers reviewing the AD7902BRQZ datasheet, AD7902BRQZ pinout, AD7902BRQZ application, or AD7902BRQZ equivalent, this page delivers verified specifications, QSOP-20 pin mapping, real-world use cases in medical instrumentation and ATE, and two validated alternative parts with documented functional and interface differences.

Technical Context

The AD7902BRQZ integrates two independent SAR ADC cores sharing no internal clock or reference coupling, enabling true simultaneous sampling with <2.0 ns aperture delay match. Each channel features an on-chip track-and-hold, zero pipeline latency, and supports independent VREF (2.4 V–5.1 V), VDD (2.375 V–2.625 V), and VIO (1.8 V–5.5 V) supplies.

Its SPI-compatible serial interface operates in CS mode or daisy-chainable chain mode, with busy indicator support and timing compatibility across 1.8 V/2.5 V/3 V/5 V logic levels. Conversion is initiated by CNVx rising edge, and results are output immediately with no latency - critical for time-aligned multichannel capture.

Key Specifications

Pinout & Package

AD7902BRQZ is housed in a 20-lead QSOP package (5.3 mm × 10.2 mm, 0.65 mm pitch), RoHS-compliant, with exposed pad not electrically connected. Pin layout supports compact PCB routing and thermal dissipation via GND-connected pads.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel 16-bit SAR ADC applications.

Compared with AD7902BRQZ, AD7903BRQZ offers superior noise immunity for differential sensors but increases system complexity, while ADS8860IDRCT reduces size and power per channel but forfeits hardware-level simultaneity and adds synchronization overhead.

Availability

AD7902BRQZ is available at Aetrix Electronics and suitable for battery-powered equipment, automated test equipment (ATE), and medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7902BRQZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with design centers worldwide.

The AD7902BRQZ belongs to the PulSAR® family of precision SAR ADCs, engineered for high-speed, low-power, simultaneous-sampling data acquisition in demanding industrial, medical, and test equipment applications.

FAQ

What is the maximum recommended reference voltage for AD7902BRQZ?

The AD7902BRQZ supports an externally applied reference voltage (REF1/REF2) from 2.4 V to 5.1 V. Operation above 5.1 V violates Absolute Maximum Ratings and may cause permanent damage. At 5.0 V reference, the device achieves optimal AC performance: 91 dB SINAD and ±1.0 LSB typical INL. Using 2.5 V reference reduces dynamic range by ~5 dB but lowers power consumption proportionally.

Does AD7902BRQZ support true simultaneous sampling across both channels?

Yes, AD7902BRQZ provides true simultaneous sampling: both ADCs initiate conversion on their respective CNV1/CNV2 rising edges with <2.0 ns aperture delay match. This hardware-level synchronization eliminates software-induced skew and enables accurate phase difference measurement - confirmed in Table 4 (Aperture Delay Match) and Figure 24 of the Rev. B datasheet.

Can AD7902BRQZ operate with a 1.8 V digital interface supply?

Yes, AD7902BRQZ supports VIO from 1.8 V to 5.5 V. At 1.8 V, digital input thresholds adjust (VIH = 0.9 × VIO = 1.62 V min; VIL = +0.1 × VIO = 0.18 V max), and SCK timing relaxes (tSCK min = 15 ns). The SDO output swing remains rail-to-rail relative to VIO, ensuring interoperability with 1.8 V FPGAs and microcontrollers without level translation.

What is the minimum acquisition time required for full 16-bit accuracy in AD7902BRQZ?

The AD7902BRQZ specifies a fixed 290 ns acquisition time (tACQ) for full 16-bit settling across all throughput rates. This value is independent of input frequency or source impedance and is guaranteed over −40°C to +125°C. External driver bandwidth (e.g., ADA4841-2) must settle within this window to avoid missing-code errors or INL degradation.

Is AD7902BRQZ pin-compatible with any other Analog Devices ADCs?

Yes, AD7902BRQZ is pin-for-pin compatible with the AD7903BRQZ (differential-input variant) as stated in the Functional Block Diagram section and Table 1 of the datasheet. Both share identical QSOP-20 pinout, timing, power, and interface behavior - enabling drop-in replacement where differential signaling is preferred over pseudo-differential architecture.