AD7870TQ

Overview

The AD7870TQ is a complete monolithic 12-bit analog-to-digital converter featuring an internal laser-trimmed clock, track-and-hold amplifier, and buried Zener reference. It operates from ±5 V supplies with a ±3 V input range. The device delivers a typical signal-to-noise ratio of 72 dB at a 10 kHz input frequency and supports conversion rates up to 100 kS/s. Data access time is 57 ns, with power dissipation typically at 60 mW. It accommodates parallel, byte, and serial digital interfaces.

Feature Summary

• Integrated on-chip 3 V buried Zener reference eliminates external component requirements.
• Laser-trimmed internal clock ensures accurate conversion timing without external oscillators.
• Versatile interface logic supports parallel, byte, and serial data output formats for flexible microprocessor integration.

Applications

• High-speed data acquisition systems requiring precise 12-bit resolution.
• Digital signal processing applications utilizing dynamic performance specifications.
• Industrial control environments operating within extended temperature ranges.

Procurement Notes

Verify the specific suffix T indicates the extended temperature grade (-55°C to +125°C) against the manufacturer's ordering guide. Confirm package availability matches the required DIP or PLCC form factor. Ensure supply chain sources provide original manufacturer documentation to validate authenticity and revision status before integration into production designs.

Selection Notes

Select the AD7870TQ when bipolar ±3 V input signals are present and extended temperature operation is mandatory. Compare dynamic performance metrics like SNR against system noise floors. Verify that the 57 ns data access time aligns with the target microprocessor bus speed. Consider the AD7875 or AD7876 if unipolar or wider voltage ranges are required instead.

Part Context

The AD7870 belongs to the LC2MOS family of complete 12-bit sampling ADCs from Analog Devices. This series integrates essential functions like tracking amplifiers and references onto a single chip. The T suffix specifically denotes the military-grade temperature extension compared to commercial variants, ensuring reliability in harsh operational environments.

Replacement Considerations

Direct replacements include other AD7870 variants with different temperature grades (J, K, L) or packages (JPZ). Cross-family alternatives like the AD7875 or AD7876 require input range adjustments. Verify pin compatibility and interface logic levels when substituting with newer generation ADCs.