Analog Devices Inc. AD7871JNZ

Overview

AD7871JNZ 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 self-contained laser-trimmed 2 MHz clock. It supports ±3 V bipolar analog input, delivers 80 dB SNR at 10 kHz, achieves 57 ns data access time, and operates from ±5 V supplies. It is used in high-speed DSP servo control and spectrum analysis systems requiring precise sampling timing.

For engineers reviewing the AD7871JNZ datasheet, AD7871JNZ pinout, AD7871JNZ application, or AD7871JNZ equivalent, this page provides verified technical context, real-world interface configurations (parallel/byte/serial), dynamic performance metrics, package-specific pin functions, and validated alternative options for signal acquisition designs.

Technical Context

The AD7871JNZ implements a SAR architecture with on-chip 14-bit DAC, high-speed comparator, and CMOS SAR logic. Its track-and-hold amplifier acquires signals to 14-bit accuracy in ≤2 μs and supports full-power input frequencies up to 41.5 kHz.

It features a factory-laser-trimmed internal 2 MHz clock - overrideable via external TTL clock on CLK pin - and a temperature-compensated 3 V buried Zener reference (±40 ppm/°C, 2.98–3.02 V over temperature) with 500 μA load capability at REF OUT.

Key Specifications

Pinout & Package

AD7871JNZ is supplied in a 28-pin plastic DIP (PDIP) package with 0.6-inch width and through-hole mounting. Pin functions are validated per Analog Devices Rev. F datasheet Figures 5 and Table 4.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7871JNZ, AD7872JNZ offers identical conversion performance in a smaller package but sacrifices parallel interface flexibility, while ADS8320U increases resolution and speed at the cost of design simplicity and bipolar capability.

Availability

AD7871JNZ is available at Aetrix Electronics and suitable for digital signal processing, high-speed modems, and spectrum analysis applications requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for AD7871JNZ 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 AD7871JNZ belongs to the LC2MOS high-speed precision ADC product line, designed specifically for demanding data acquisition systems requiring integrated timing, reference, and interface logic in a single monolithic IC.

FAQ

What is the maximum analog input frequency supported by the AD7871JNZ?

The AD7871JNZ can accurately convert full-power analog input signals up to 41.5 kHz. This is determined by its track-and-hold amplifier's 500 kHz 0.1 dB bandwidth and 2 μs acquisition time, ensuring 14-bit settling across the Nyquist band. The 83 kSPS throughput rate satisfies the Nyquist criterion for this frequency range, making AD7871JNZ suitable for baseband and low-IF sampling applications.

Does the AD7871JNZ require external clock components?

No, the AD7871JNZ does not require external clock components. It integrates a self-contained, laser-trimmed 2 MHz internal oscillator. Connecting CLK to VSS enables this internal clock; alternatively, an external TTL-compatible clock may be applied to CLK for system-level synchronization. The AD7871JNZ datasheet confirms no external timing components are needed for basic operation.

How is bipolar offset error trimmed on the AD7871JNZ?

Bipolar offset error on the AD7871JNZ is trimmed by adjusting the offset of the op amp driving VIN while applying −0.183 mV (−½ LSB) to the analog input. The trim point is confirmed when the ADC output code toggles between 0x0000 and 0x7FFF. This procedure is documented in the AD7871JNZ datasheet Section "Bipolar Offset Scale Adjustment" and requires no internal device modification.

Can the AD7871JNZ operate with a single +5 V supply?

No, the AD7871JNZ requires dual ±5 V supplies (VDD = +5 V, VSS = −5 V) for specified operation. The analog input range is ±3 V, and internal circuitry - including the track-and-hold amplifier and buried Zener reference - depends on the negative rail. Operation outside the absolute maximum ratings (e.g., VSS = 0 V) risks permanent damage and invalidates all specifications for AD7871JNZ.

What is the purpose of the CREF pin on the AD7871JNZ?

The CREF pin on the AD7871JNZ serves as the decoupling node for the on-chip 3 V buried Zener reference. A 10 nF capacitor must be connected between CREF and AGND to suppress reference noise and ensure stable DC accuracy and dynamic performance. This requirement is explicitly stated in the AD7871JNZ datasheet "Internal Reference" section and is mandatory for achieving specified INL and SNR.