Analog Devices Inc. AD7896ANZ

Overview

AD7896ANZ from Analog Devices is a fast, 12-bit successive-approximation ADC with 8 µs conversion time, single 2.7 V to 5.5 V supply operation, and integrated track-and-hold amplifier and on-chip clock. It delivers 100 kHz throughput, 70 dB SNR at 10 kHz input, and operates in 8-lead PDIP (0.3" wide) for embedded data acquisition in portable instrumentation and sensor interfaces.

For engineers reviewing the AD7896ANZ datasheet, AD7896ANZ pinout, AD7896ANZ application, or AD7896ANZ equivalent, key selection considerations include its unipolar 0 V to VDD analog input range, 2-wire high-speed serial interface (SCLK/SDATA), automatic power-down mode for battery operation, and absence of external reference requirement due to VDD-referenced architecture.

Technical Context

The AD7896ANZ implements an R-2R ladder-based successive approximation ADC with laser-trimmed internal clock, eliminating need for external timing components. Its track-and-hold amplifier acquires signals to 12-bit accuracy within 1.5 µs and supports full-scale sine wave inputs up to 50 kHz.

It offers two operating modes: Mode 1 (high sampling, 8 µs conversion, BUSY-driven timing) and Mode 2 (auto-sleep, 14 µs total cycle including 6 µs wake-up), both using edge-triggered CONVST control and BUSY status signaling. Serial output delivers 16-bit frames (4 leading zeros + 12-bit straight binary MSB-first) synchronized to SCLK falling edges.

Key Specifications

Pinout & Package

AD7896ANZ is housed in an 8-lead, 0.3" wide plastic dual-in-line package (PDIP) with standard through-hole mounting and JEDEC MS-001AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and MAX11131EUB+, the AD7896ANZ uniquely combines 12-bit accuracy, VDD-referencing, auto-sleep power management, and PDIP packaging - making it optimal for cost-sensitive, battery-operated, or manually assembled precision data acquisition where external reference elimination and long-term reliability are critical.

Availability

AD7896ANZ 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 extended product lifecycles.

Supply support for AD7896ANZ 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7896ANZ belongs to Analog Devices' legacy precision SAR ADC product line, designed specifically for space-constrained, low-power, single-supply data acquisition systems where integration, simplicity, and reliability outweigh ultra-high speed or ultra-low noise requirements.

FAQ

What is the maximum serial clock frequency supported by the AD7896ANZ?

The AD7896ANZ supports a maximum SCLK frequency of 10 MHz when operated at 5 V ±10%. At 2.7 V to 3.6 V, timing margins reduce the practical maximum to approximately 6.5 MHz due to increased data access time (t4 = 100 ns). The part requires precise setup and hold timing relative to SCLK falling edges, so system-level timing analysis must account for controller output delays and board trace propagation.

Does the AD7896ANZ require an external voltage reference?

No, the AD7896ANZ does not require an external voltage reference. Its internal reference is derived directly from the VDD supply rail, enabling a 0 V to VDD analog input range. This eliminates external reference components, reduces BOM cost and PCB area, and simplifies layout - a key advantage confirmed in the AD7896ANZ product highlights and functional block diagram.

How does the AD7896ANZ enter and exit power-down mode?

The AD7896ANZ enters power-down mode automatically when CONVST remains low after conversion completes (indicated by BUSY going low). It exits power-down on the rising edge of CONVST, with a 6 µs wake-up time before track-and-hold enters hold mode. This behavior is exclusive to Mode 2 operation and is documented in the AD7896ANZ timing diagrams and operating modes section.

What is the analog input impedance of the AD7896ANZ, and how does it affect driving circuitry?

While the AD7896ANZ does not specify a static input resistance, its track-and-hold architecture presents a dynamic load during acquisition. To achieve 12-bit accuracy within the 1.5 µs acquisition time, the driving source must have ≤1 kΩ output impedance. Higher impedances cause settling errors; this requirement is explicitly stated in the AD7896ANZ analog input section and verified in the converter details.

Can the AD7896ANZ interface directly with a microcontroller's SPI peripheral?

The AD7896ANZ uses a 2-wire serial interface (SCLK and SDATA) with data clocked on SCLK falling edges, but it lacks a chip select (CS) line and does not conform to standard SPI framing. While many microcontrollers can bit-bang the protocol successfully, direct hardware SPI peripheral use typically requires firmware adaptation to manage timing, frame length (16 bits), and BUSY synchronization - as detailed in the AD7896ANZ serial interface section.