Analog Devices Inc. AD7871KNZ

Overview

AD7871KNZ from Analog Devices is a complete monolithic 14-bit LC2MOS successive approximation ADC with integrated track-and-hold amplifier, 3 V buried Zener reference, and self-contained laser-trimmed internal clock. It delivers 83 kSPS throughput, 80 dB SNR at 10 kHz, 57 ns data access time, ±3 V bipolar input range, and supports parallel (14-bit or byte), serial, and mixed interface modes. It is used in high-speed DSP servo control and spectrum analysis systems requiring stable dc accuracy and dynamic performance.

For engineers reviewing the AD7871KNZ datasheet, AD7871KNZ pinout, AD7871KNZ application, or AD7871KNZ equivalent, key selection considerations include its dual-supply (±5 V) operation, 28-pin PDIP package, three configurable output formats (14-bit parallel / two-byte / serial), internal clock override capability, and full specification for both dc accuracy (±1 LSB INL max) and dynamic parameters (THD −86 dB max).

Technical Context

The AD7871KNZ implements a SAR architecture with a voltage-output DAC, high-speed comparator, and CMOS SAR logic, all on a single LC2MOS die. Its track-and-hold acquires to 14-bit accuracy in ≤2 μs, enabling full-power conversion of signals up to 41.5 kHz while maintaining 80 dB SNR.

It integrates a temperature-compensated 3 V buried Zener reference (±40 ppm/°C, 2.98–3.02 V over temp) with dedicated CREF decoupling pin and REFOUT capable of sourcing 500 μA. The 14/8/CLK pin configures interface mode: +5 V enables 14-bit parallel only; 0 V enables byte/serial with gated SCLK; −5 V enables byte/serial with continuous SCLK.

Key Specifications

Pinout & Package

The AD7871KNZ is housed in a 28-pin plastic DIP (PDIP) package with 0.6-inch 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 SAR ADC applications.

Compared with AD7871KNZ, AD7872KNZ reduces pin count and interface flexibility but saves board area, while ADS8320U trades integrated functionality for higher resolution and modern serial protocol-neither is pin-compatible, and all require distinct layout and firmware adaptation.

Availability

AD7871KNZ is available at Aetrix Electronics and suitable for digital signal processing systems, high-speed modem designs, and spectrum analysis instruments requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for AD7871KNZ 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 AD7871KNZ belongs to the AD7871/AD7872 family of complete 14-bit sampling ADCs designed for demanding DSP, communications, and instrumentation applications where integration, dynamic performance, and ease of use are critical.

FAQ

What power supplies does the AD7871KNZ require?

The AD7871KNZ operates from dual ±5 V supplies (VDD = +5 V ±5%, VSS = −5 V ±5%) with separate analog (AGND) and digital (DGND) ground returns. Typical total power dissipation is 50 mW, with IDD ≈ 6 mA and ISS ≈ 4 mA. Decoupling capacitors (0.1 μF ceramic + 10 μF tantalum) are required on each supply pin near the device.

Does the AD7871KNZ include an internal reference?

Yes, the AD7871KNZ integrates a factory-laser-trimmed, temperature-compensated 3 V buried Zener reference. It provides the DAC reference and bias for bipolar operation. REFOUT delivers 2.98–3.02 V over temperature (±40 ppm/°C) and supports up to 500 μA load. CREF must be decoupled to AGND with a 10 nF capacitor.

How does the AD7871KNZ handle different digital interface configurations?

The AD7871KNZ uses the 14/8/CLK pin to configure interface mode: +5 V selects 14-bit parallel only; 0 V enables both byte and serial outputs with gated SCLK; −5 V enables byte/serial with continuous SCLK. HBEN (Pin 6) selects upper/lower byte in 8-bit mode, and BUSY/INT (Pin 4) provides conversion status for handshaking.

What is the maximum analog input frequency the AD7871KNZ can accurately digitize?

The AD7871KNZ supports full-power analog input signals up to 41.5 kHz while maintaining specified dynamic performance (80 dB SNR, −86 dB THD). Its track-and-hold amplifier has a 0.1 dB cutoff typically at 500 kHz, and acquisition time is ≤2 μs-enabling accurate sampling well beyond its 83 kSPS throughput limit.

Is the AD7871KNZ RoHS compliant and what is its operating temperature range?

Yes, the AD7871KNZ (K version) is RoHS compliant and rated for commercial operation from 0°C to +70°C. Absolute maximum ratings include storage from −65°C to +150°C and lead temperature up to +300°C for 10 seconds. Full dc and dynamic specifications are guaranteed across the entire operating temperature range.