Analog Devices Inc. AD7872ANZ

Overview

AD7872ANZ from Analog Devices is a complete monolithic 14-bit successive approximation analog-to-digital converter (ADC) with integrated track-and-hold amplifier, 3 V buried Zener reference, and serial-only digital interface. It operates from ±5 V supplies, accepts bipolar ±3 V analog inputs, delivers 83 kSPS throughput, achieves 80 dB SNR at 10 kHz, and features 57 ns data access time. It is used in high-speed DSP servo control and spectrum analysis systems requiring precise sampling timing.

For engineers reviewing the AD7872ANZ datasheet, AD7872ANZ pinout, AD7872ANZ application, or AD7872ANZ equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative options with functional differences, and supply support details for industrial embedded and signal processing designs.

Technical Context

The AD7872ANZ implements a self-contained LC2MOS SAR architecture with laser-trimmed internal 2 MHz clock-no external timing components required-and uses a high-speed track-and-hold amplifier acquiring to 14-bit accuracy in ≤2 μs. Its serial interface outputs 14-bit twos-complement data via SDATA, SCLK, and SSTRB pins with framing synchronized to falling SCLK edges.

It integrates a temperature-compensated 3 V buried Zener reference (±40 ppm/°C max, 2.98–3.02 V over temperature) decoupled at CREF with 10 nF to AGND, and supports bipolar input operation without external level-shifting circuitry. The device requires no external DAC, reference buffer, or clock generator to function as a standalone ADC subsystem.

Key Specifications

Pinout & Package

AD7872ANZ is housed in a 16-pin plastic DIP (PDIP) package with 0.3-inch body width and through-hole mounting. Pin 1 is marked by a notch or dot; pins are numbered counterclockwise from top-left corner when viewed from top.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 14-bit serial-output ADC applications.

Compared with AD7872ANZ, AD7870KN trades resolution and interface flexibility for raw speed, while ADS8320U adds resolution and modern SPI compatibility at the cost of external reference dependency and tighter layout constraints-AD7872ANZ remains optimal for compact, self-contained 14-bit serial acquisition.

Availability

AD7872ANZ is available at Aetrix Electronics and suitable for digital signal processing, high-speed modems, spectrum analysis, and DSP servo control applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7872ANZ 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 and manufacturing facilities worldwide.

The AD7872ANZ belongs to Analog Devices' legacy high-speed precision ADC product line, engineered specifically for demanding real-time signal acquisition in industrial instrumentation, communications infrastructure, and automated test equipment where integration, timing fidelity, and dc/dynamic accuracy are co-critical.

FAQ

What is the maximum analog input frequency supported by the AD7872ANZ?

The AD7872ANZ supports full-power analog input signals up to 41.5 kHz, determined by its 83 kSPS throughput rate and Nyquist criterion. This is validated in the datasheet under "GENERAL DESCRIPTION" and confirmed by dynamic performance testing at 10 kHz input frequency with 80 dB SNR. The track-and-hold amplifier's 500 kHz 0.1 dB bandwidth ensures faithful capture of signals within this range without aliasing-induced distortion in properly filtered systems.

Does the AD7872ANZ require an external clock to operate?

No, the AD7872ANZ does not require an external clock. It features a built-in laser-trimmed 2 MHz oscillator activated by tying the CLK pin to VSS. This internal clock enables fully autonomous operation-no crystal, oscillator IC, or timing passive components are needed. External clocks are optional and accepted via the CLK pin for synchronization to system timing domains, but are not mandatory for basic functionality of the AD7872ANZ.

How is the serial data format structured on the AD7872ANZ?

The AD7872ANZ outputs a 14-bit twos-complement serial word, MSB-first, synchronized to the falling edge of SCLK and framed by the active-low SSTRB pulse. Data appears on SDATA during SCLK low periods and is latched by the host on SCLK falling edges. The CONTROL pin selects SCLK behavior: 0 V yields gated SCLK (active only during transmission), while −5 V enables continuous SCLK-both modes are fully compatible with standard shift-in registers used with the AD7872ANZ.

What is the purpose of the CREF pin on the AD7872ANZ?

The CREF pin on the AD7872ANZ is the dedicated decoupling terminal for the internal 3 V buried Zener reference. A 10 nF capacitor must be connected between CREF and AGND to suppress high-frequency noise and maintain the specified 80 dB SNR performance. This capacitor is not optional-it is explicitly required in the datasheet's "INTERNAL REFERENCE" section and directly impacts reference stability, THD, and overall ADC accuracy in the AD7872ANZ.

Can the AD7872ANZ operate with unipolar input signals?

Yes, the AD7872ANZ can operate with unipolar inputs using an external offset circuit. Figure 14 in the datasheet shows a standard configuration where the internal REFOUT (3 V) biases the analog input to shift the ±3 V bipolar range to 0–6 V. With appropriate resistor scaling (e.g., R3/R4), input ranges of 0–5 V or 0–10 V are achievable. The output remains twos-complement and can be converted to straight binary by inverting the MSB-this unipolar mode is fully supported and characterized for the AD7872ANZ.