AD7878SQ/883B

Overview

The AD7878SQ/883B is a complete 12-bit, 100 kHz sampling Analog-to-Digital Converter (ADC) fabricated in LC2MOS technology. It features an on-chip track/hold amplifier with 2 μs acquisition time, a 3 V zener reference, and an 8-word FIFO memory for DSP interfacing. The device operates from ±5 V supplies (VDD, VCC, VSS) with a bipolar analog input range of ±3 V. Key electrical parameters include a minimum Signal-to-Noise Ratio (SNR) of 70 dB at 10 kHz input frequency, a maximum data access time of 57 ns, and typical power dissipation of 60 mW. It supports a conversion time of 7 μs to 9.25 μs depending on bus activity.

Feature Summary

• Integrated 8-word First-In-First-Out (FIFO) memory reduces software overhead by allowing multiple samples to be digitized before microprocessor servicing.
• Versatile DSP interface logic enables direct connection to high-speed processors like the ADSP-2100 and TMS320 series.
• On-chip status and control register provides real-time monitoring of FIFO word count, empty/full states, and sample overrange conditions.

Applications

• Digital Signal Processing systems
• Speech recognition and synthesis equipment
• Spectrum analysis instruments
• High-speed modem implementations
• DSP-based servo control loops

Procurement Notes

Verify that the ordering suffix /883B confirms MIL-STD-883 Class B processing requirements are met for the specific application environment. Confirm package availability as Analog Devices may ship either ceramic DIP or hermetic cerdip packages for this variant. Ensure supply chain sources provide valid traceability documentation consistent with military-grade specifications.

Selection Notes

Select the AD7878SQ/883B when extended temperature operation from -55°C to +125°C is required. This model offers a 70 dB SNR specification, which is lower than the SQ grade's 72 dB counterpart but sufficient for many general-purpose applications. Verify that the 57 ns data access time aligns with the target microprocessor's timing constraints.

Part Context

This component belongs to the AD7878 family of complete ADCs designed for digital signal processing interfaces. The 'SQ' designation indicates the S-grade version capable of operating across the full military temperature range. The '/883B' suffix denotes compliance with MIL-STD-883 standards, distinguishing it from commercial or industrial grade variants like the JN or AQ models.

Replacement Considerations

Public confirmed substitute part numbers: AD7878SQ.