AD7874SQ

ADCs/DACs - Special Purpose Overview

The AD7874SQ is a four-channel, 12-bit simultaneous sampling data acquisition system designed for extended industrial and military environments. Operating within a temperature range of –55°C to +125°C, it integrates four track/hold amplifiers, a high-speed successive approximation ADC, an internal clock, and a reference buffer. The device supports ±5 V dual supplies and features a parallel interface with 2s complement output coding. Key electrical specifications include a maximum aperture delay matching of 4 ns, a typical signal-to-noise ratio of 70 dB at a 29 kHz sample rate, and a power dissipation of 150 mW.

ADCs/DACs - Special Purpose Feature Summary

• Simultaneous Sampling: Four independent on-chip track/hold amplifiers preserve relative phase information across all channels.
• Extended Temperature Range: Qualified for operation from –55°C to +125°C (S Version).
• High-Speed Interface: Parallel digital interface allows direct connection to 16-bit microprocessors and DSPs.
• Integrated Reference: On-chip laser-trimmed 3 V reference with REF OUT capability for multi-device synchronization.

ADCs/DACs - Special Purpose Applications

• Phased-array sonar systems requiring precise channel phase alignment.
• AC motor controllers utilizing simultaneous current and voltage sampling.
• Adaptive filters and digital signal processing architectures.
• Multi-point vibration measurement and power system monitoring.

ADCs/DACs - Special Purpose Procurement Notes

Verify the package option Q-28 (Cerdip) matches the target PCB footprint. Confirm that the S version temperature rating aligns with the environmental requirements. Ensure supply rails are strictly maintained within ±5% of nominal ±5 V to meet specified performance parameters. Check for MIL-STD-883 Class B processing availability if required by specific reliability standards.

ADCs/DACs - Special Purpose Selection Notes

Select the AD7874SQ when simultaneous sampling of four channels is critical to maintain phase integrity, distinguishing it from multiplexed ADCs. The S version is required for applications exceeding the commercial –40°C lower limit. Compare SNR and linearity against the B version if higher dynamic performance is needed, noting the SQ offers standard accuracy. Ensure the system can accommodate the 28-pin Cerdip package constraints.

ADCs/DACs - Special Purpose Part Context

The AD7874 belongs to Analog Devices' LC2MOS family of data acquisition systems. It is part of a broader lineup including the AD7870 and AD7875. The 'SQ' suffix specifically denotes the S version (–55°C to +125°C) in the Q-28 Cerdip package. This variant is often selected for ruggedized or military-grade electronics where thermal stability and hermetic sealing are prioritized over plastic packaging options.

ADCs/DACs - Special Purpose Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. The datasheet notes that /883B processing is available upon request but does not list alternative cross-reference models.