Analog Devices Inc. AD7903BRQZ-RL7

Overview

AD7903BRQZ-RL7 from Analog Devices is a dual 16-bit, 1 MSPS successive approximation analog-to-digital converter (ADC) with true differential inputs, ±VREF range, no pipeline delay, and serial SPI/QSPI/MICROWIRE interface. It operates from single 2.5 V supply per ADC and supports 1.8 V to 5 V logic via separate VIO supplies. Used in simultaneous-sampling data acquisition systems requiring high channel matching and low power.

For engineers reviewing the AD7903BRQZ-RL7 datasheet, AD7903BRQZ-RL7 pinout, AD7903BRQZ-RL7 application, or AD7903BRQZ-RL7 equivalent, key selection criteria include guaranteed 16-bit no-missing-codes performance, ±2.0 LSB max INL at −40°C to +125°C, 93.5 dB SINAD at 1 kHz, 12.0 mW total power at 1 MSPS, and QSOP-20 package compatibility with AD7902.

Technical Context

The AD7903BRQZ-RL7 implements two independent successive approximation register (SAR) ADCs sharing a common reference but with separate CNVx, SCKx, SDIx, and SDOx interfaces. Each ADC features on-chip track-and-hold, zero pipeline latency, and aperture delay match of 2.0 ns. Conversion is initiated on the rising edge of CNVx, sampling the differential voltage between INx+ and INx−.

It supports two digital interface modes: CS mode (active-low chip select) and chain mode (daisy-chainable), both compatible with 1.8 V/2.5 V/3 V/5 V logic levels via dedicated VIO1/VIO2 supplies. Reference voltage (2.4 V to 5.1 V) is externally applied to REF1/REF2 and decoupled with 10 μF capacitors to GND.

Key Specifications

Pinout & Package

AD7903BRQZ-RL7 is housed in a 20-lead QSOP package (5.3 mm × 10.2 mm, 0.65 mm pitch), rated for −40°C to +125°C operation. Pin assignments are validated per Analog Devices AD7903 Rev. B datasheet, Figure 4 and Table 6.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7902BRQZ, AD7903BRQZ-RL7 adds true differential input and improved channel isolation but shares identical footprint and digital interface; versus ADS8860IDRCT, it delivers integrated dual-channel synchronization at lower system-level BOM cost despite larger package size.

Availability

AD7903BRQZ-RL7 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 AD7903BRQZ-RL7 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.

The AD7903 belongs to the PulSAR® family of precision SAR ADCs, designed specifically for high-speed, low-power, simultaneous-sampling data acquisition in demanding industrial, medical, and test equipment applications.

FAQ

What is the maximum sampling rate supported by the AD7903BRQZ-RL7?

The AD7903BRQZ-RL7 supports a maximum throughput of 1 MSPS per channel, verified across the full −40°C to +125°C operating temperature range. At this rate, total power dissipation is 12.0 mW, with 7.0 mW attributed to VDD supplies and 3.3 mW to the reference circuitry. The conversion time from CNVx rising edge to valid data is 710 ns maximum.

Does the AD7903BRQZ-RL7 require an external clock for conversion?

No, the AD7903BRQZ-RL7 does not require an external clock for the analog conversion process. It contains an on-chip conversion clock. The SCKx signal is used solely for serial data readout timing and supports daisy-chain configurations. This eliminates jitter-sensitive clock distribution and simplifies system design compared to pipeline or sigma-delta ADCs.

Can the AD7903BRQZ-RL7 operate with a 3.3 V digital interface while using a 2.5 V analog supply?

Yes, the AD7903BRQZ-RL7 supports independent supply domains: VDD1/VDD2 at 2.5 V for analog circuitry and VIO1/VIO2 at 3.3 V for digital I/O. This allows seamless interfacing with 3.3 V microcontrollers or FPGAs while maintaining optimal analog performance. Logic thresholds automatically scale with VIO, and VOL/VOH specifications are guaranteed across 1.8 V–5.5 V VIO range.

What is the purpose of the REF1 and REF2 pins on the AD7903BRQZ-RL7?

The REF1 and REF2 pins on the AD7903BRQZ-RL7 provide independent reference voltage inputs for each ADC channel, supporting true differential input ranges of ±VREF. Each accepts 2.4 V–5.1 V and must be decoupled to GND with a 10 µF capacitor. Using separate references enables mismatch-tolerant designs and eliminates shared-reference crosstalk in high-precision applications.

Is the AD7903BRQZ-RL7 pin-compatible with any other Analog Devices ADCs?

Yes, the AD7903BRQZ-RL7 is pin-for-pin compatible with the AD7902BRQZ, a pseudo-differential dual 16-bit SAR ADC in the same 20-lead QSOP package. This allows drop-in replacement where true differential input is not required, simplifying design reuse and migration paths within the PulSAR® portfolio.