Analog Devices Inc. AD7896BRZ

Overview

AD7896BRZ from Analog Devices is a single-supply, 12-bit successive approximation ADC with 8 µs conversion time, integrated track-and-hold and on-chip clock, housed in an 8-lead SOIC package. It operates from 2.7 V to 5.5 V, accepts 0 V to VDD analog input, delivers 100 kHz throughput, and consumes 9 mW typical-enabling compact, low-power data acquisition in portable instrumentation and sensor interfaces.

For engineers reviewing the AD7896BRZ datasheet, AD7896BRZ pinout, AD7896BRZ application, or AD7896BRZ equivalent, key selection considerations include its 2-wire serial interface timing (SCLK up to 10 MHz), auto power-down mode for battery operation, unipolar 0–VDD input range, ±1 LSB relative accuracy, and SOIC-8 thermal performance (θ_JA = 160°C/W).

Technical Context

The AD7896BRZ implements a laser-trimmed R-2R ladder SAR architecture with internal VDD-derived reference, eliminating external voltage references. Its track-and-hold amplifier achieves 1.5 µs acquisition time to 12-bit accuracy and supports full-scale sine-wave inputs up to 50 kHz.

It features two operating modes: Mode 1 (high-speed, 8 µs conversion, BUSY-driven timing) and Mode 2 (auto-sleep, 14 µs total cycle including 6 µs wake-up). Serial data output is straight binary, 16-bit frame (4 leading zeros + 12-bit result), clocked on SCLK falling edge with guaranteed 10 ns hold time.

Key Specifications

Pinout & Package

AD7896BRZ is packaged in an 8-lead, 0.150" wide SOIC (Small Outline Integrated Circuit) with standard JEDEC MS-012AC footprint, θ_JA = 160°C/W, rated for commercial temperature range (0°C to +70°C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS7822U and MAX11131ASA+, the AD7896BRZ uniquely balances ultra-low pin count (8-lead SOIC), VDD-referenced simplicity, and intelligent power management-making it optimal for cost-sensitive, battery-operated, or space-limited 100 kHz-class data acquisition where external reference elimination and minimal I/O are design priorities.

Availability

AD7896BRZ is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor interfaces, and medical vital sign monitors requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for AD7896BRZ 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 AD7896BRZ belongs to Analog Devices' legacy precision SAR ADC product line, designed specifically for low-power, single-supply, space-constrained data acquisition systems where integration, simplicity, and reliability outweigh raw speed.

FAQ

What is the maximum serial clock frequency supported by the AD7896BRZ?

The AD7896BRZ supports SCLK up to 10 MHz under 5 V operation. At this frequency, the serial read takes 1.6 µs for the full 16-bit frame. Timing margins require t₄ (data access time) ≤ 60 ns and t₅ (data hold time) ≥ 10 ns-both met at 10 MHz with VDD = 5 V. Lower VDD reduces maximum usable SCLK due to increased t₄.

Does the AD7896BRZ require an external voltage reference?

No, the AD7896BRZ does not require an external voltage reference. Its internal reference is derived directly from the VDD supply, enabling a true single-supply, 0 V to VDD analog input range. This eliminates external reference components and associated layout complexity while maintaining ±1 LSB relative accuracy across temperature.

How does the auto power-down mode function in the AD7896BRZ?

In auto power-down mode (Mode 2), the AD7896BRZ enters low-current sleep immediately after BUSY goes low at conversion completion. It remains in sleep until the rising edge of the next CONVST pulse triggers a 6 µs wake-up, after which conversion begins. This reduces average IDD to 5 µA typ (2.7–3.6 V), extending battery life in intermittent-sampling applications without sacrificing accuracy.

What is the analog input impedance of the AD7896BRZ, and how does it affect sensor interfacing?

The AD7896BRZ VIN pin presents high input impedance, allowing direct connection to sources with output impedance ≤1 kΩ. This ensures full 12-bit settling within the 1.5 µs track-and-hold acquisition time. For higher-impedance sensors, an external op-amp buffer is recommended to prevent gain error and code flicker caused by incomplete settling.

Can the AD7896BRZ interface directly with common microcontroller SPI peripherals?

Yes-the AD7896BRZ's 2-wire serial interface (SCLK + SDATA) is compatible with most microcontroller SPI hardware when configured for slave mode with CPOL = 0, CPHA = 1 (sample on falling edge). The 16-bit frame (4 leading zeros + 12-bit result) aligns with standard SPI shift registers; BUSY provides optional hardware handshaking for precise timing control in the AD7896BRZ.