Analog Devices Inc. AD7896BN

Overview

AD7896BN from Analog Devices is a fast, single-supply 12-bit successive-approximation ADC with 8 µs conversion time, integrated track-and-hold amplifier and on-chip clock, housed in an 8-lead PDIP package. It operates from 2.7 V to 5.5 V, accepts 0 V to VDD analog input, delivers 100 kHz throughput, and consumes only 9 mW typical - enabling compact, low-power data acquisition in portable instrumentation and sensor interfaces.

For engineers reviewing the AD7896BN datasheet, AD7896BN pinout, AD7896BN application, or AD7896BN 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 J-version temperature range (0°C to +70°C) specified for commercial use.

Technical Context

The AD7896BN implements a laser-trimmed R-2R ladder SAR architecture with internal VDD-derived reference, eliminating external voltage references. Its track-and-hold acquisition time is 1.5 µs, supporting full-scale sine-wave sampling at up to 50 kHz input bandwidth without aliasing.

It supports 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), both synchronized via edge-triggered CONVST and validated by BUSY status signaling.

Key Specifications

Pinout & Package

AD7896BN is packaged in an 8-lead, 0.3" wide plastic dual-in-line package (PDIP), compliant with JEDEC MS-001 standard. Pin spacing is 0.1" (2.54 mm), with 0.3" body width and through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7896ARZ, AD7896BN offers mechanical robustness and hand-solderability at the expense of board area; versus ADS7822U, AD7896BN reduces component count and sleep-mode power by integrating reference and auto-power-down - critical for long-life portable instruments.

Availability

AD7896BN is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor interfaces, medical vital sign monitors, and test equipment requiring stable component supply across commercial temperature ranges.

Supply support for AD7896BN 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 AD7896BN belongs to Analog Devices' precision data acquisition product line, designed specifically for low-power, space-constrained, single-supply 12-bit ADC applications in commercial and industrial environments.

FAQ

What is the operating temperature range for the AD7896BN?

The AD7896BN is the J-version variant, rated for 0°C to +70°C operation. This commercial temperature range is validated per Analog Devices' specifications and applies to all electrical parameters in the datasheet unless otherwise noted. The AD7896BN does not support extended industrial (–40°C to +85°C) or military (–55°C to +125°C) ranges - those require A/B or S versions respectively. Always verify ambient and junction temperature limits using the 125°C/W θJA value for the PDIP package.

Does the AD7896BN require an external voltage reference?

No, the AD7896BN does not require an external voltage reference. Its internal reference is derived directly from the VDD supply pin, enabling a 0 V to VDD analog input range. This eliminates the need for external reference ICs, decoupling capacitors, and associated layout constraints - reducing BOM cost and PCB area. The AD7896BN maintains ±1 LSB relative accuracy across 2.7 V to 5.5 V VDD, with no performance degradation due to VDD variation within that range.

How does the auto power-down mode work on the AD7896BN?

The AD7896BN enters auto power-down mode when the CONVST pin remains low after conversion completes (i.e., after BUSY goes low). In this state, quiescent current drops to 5 µA typical at 2.7–3.6 V. The part "wakes up" on the rising edge of the next CONVST pulse, with a 6 µs wake-up time before track-and-hold transitions to hold mode. Total Mode 2 conversion time is 14 µs (6 µs wake-up + 8 µs conversion), confirmed in the AD7896BN datasheet timing diagrams and validated across the J-version temperature range.

What is the maximum SCLK frequency supported by the AD7896BN?

The AD7896BN supports a maximum SCLK frequency of 10 MHz when operated at VDD = 5 V ±10%. At VDD = 2.7 V to 3.6 V, the maximum SCLK is limited by timing parameter t4 (data access time), which increases to 100 ns - effectively capping reliable SCLK at ~8 MHz. The 10 MHz limit assumes proper setup/hold timing margins and accounts for t2/t3 (SCLK high/low pulsewidth ≥402 ns) and t4/t5 (data validity window). Exceeding these values risks read errors, especially during high-throughput Mode 1 operation.

Can the AD7896BN interface directly with a microcontroller SPI peripheral?

The AD7896BN uses a 2-wire serial interface (SCLK and SDATA only) with no chip select (CS) or MOSI lines, so it is not SPI-compatible out-of-the-box. However, it can be interfaced to most microcontrollers using bit-banged GPIO or by configuring an SPI peripheral in master mode with CS disabled and SCLK/SDO pins mapped to SCLK/SDATA. The AD7896BN outputs 16 bits (4 zeros + 12-bit result, MSB-first) on the falling SCLK edge, requiring precise timing alignment - confirmed in Figure 4 of the AD7896BN datasheet.