AD7870JNZ

Overview

The AD7870JNZ is a complete monolithic 12-bit analog-to-digital converter (ADC) from Analog Devices. It integrates a track-and-hold amplifier, an 8 μs successive approximation ADC, and a laser-trimmed internal clock. The device operates on ±5 V power supplies with a typical power dissipation of 60 mW. It features a single-ended analog input range of ±3 V and provides parallel, byte, or serial digital interfaces. Key performance metrics include a signal-to-noise ratio of 70 dB at a 10 kHz input frequency, a data access time of 57 ns, and a sampling rate up to 100 kS/s. The component is housed in a 24-pin PDIP package.

Feature Summary

• Integrates a 2 μs track-and-hold amplifier and a self-contained internal clock for accurate conversion timing without external components.
• Offers versatile digital interface options including parallel, byte, and serial data output formats for easy microprocessor interfacing.
• Includes a factory-trimmed 3 V buried Zener reference with temperature compensation and external load capability.
• Provides fast bus access times compatible with modern 8-bit and 16-bit microprocessors and digital signal processors.

Applications

• Data acquisition systems requiring high-speed 12-bit resolution
• Digital signal processing (DSP) front-ends
• Portable battery-powered instrumentation
• Industrial control systems

Procurement Notes

Verify the specific suffix JNZ corresponds to the commercial temperature range (0°C to +70°C) and the 24-pin plastic dual-in-line package (PDIP). Confirm that the ordering part number matches the exact pinout and electrical specifications required for the design, as other suffixes may indicate different packages or extended temperature ranges.

Selection Notes

Select the AD7870JNZ when a single-ended ±3 V input range is required. Ensure the system can support ±5 V power supplies. Consider the AD7875 if a unipolar 0 V to +5 V input is needed, or the AD7876 for a ±10 V range. Verify that the 12/8/CLK pin configuration aligns with the desired data output format for the target microcontroller.

Part Context

The AD7870 is part of the AD7870/AD7875/AD7876 family of LC2MOS 12-bit sampling ADCs. While sharing core architecture, the AD7870 is distinctively configured for bipolar ±3 V inputs. Other family members like the AD7875 offer unipolar inputs, and the AD7876 supports wider bipolar ranges. All variants share similar interface logic and power characteristics.

Replacement Considerations

Direct functional substitutes within the same family include the AD7875KNZ for unipolar applications and the AD7876KNZ for wider bipolar ranges. For industrial temperature grades (-40°C to +85°C), consider the AD7870KNZ variant which shares the same electrical specifications but offers an extended operating range.