AD7878SE/883B

Overview

The AD7878SE/883B is a military-grade, complete 12-bit analog-to-digital converter fabricated in LC2MOS technology. It features an integrated track/hold amplifier with a 2 μs acquisition time and a 3 V zener reference. The device includes an 8-word FIFO memory and DSP interface logic, enabling direct connection to high-speed processors like the ADSP-2100. Key electrical parameters include a maximum data access time of 57 ns, a signal-to-noise ratio of 70 dB at a 10 kHz input frequency, and a typical power dissipation of 60 mW. It operates on dual ±5 V supplies and supports a bipolar analog input range of ±3 V.

Feature Summary

• Integrated 8-word first-in, first-out (FIFO) memory reduces software overhead for servicing interrupts in digital signal processors.
• Versatile DSP interface allows direct interfacing with high-speed microprocessors via a fast 41 ns to 57 ns data access time.
• On-chip status and control register provides programmable FIFO word counts, overrun detection, and out-of-range monitoring.
• Extended read/write capability prevents bus transients during conversion by disabling three-state drivers while the BUSY signal is active.

Applications

• Digital Signal Processing
• Speech Recognition and Synthesis
• Spectrum Analysis
• High Speed Modems
• DSP Servo Control

Procurement Notes

Verify that the ordering suffix /883B confirms MIL-STD-883 Class B processing, as this denotes specific military qualification requirements distinct from commercial variants. Confirm the package option corresponds to the E-28A leadless ceramic chip carrier specified for the SE grade. Ensure the component meets the extended temperature range of –55°C to +125°C required for the S version specifications.

Selection Notes

Select the AD7878SE/883B when military reliability standards are mandatory alongside high-speed data acquisition needs. This variant is suitable for designs requiring a 70 dB SNR and 57 ns access time within an industrial or aerospace environment. Consider the integrated FIFO if minimizing processor interrupt latency is critical. Verify that the system can accommodate the required ±5 V supply rails and the specific pinout of the leadless ceramic chip carrier package.

Part Context

The AD7878 series consists of complete 12-bit ADCs designed for direct interfacing with digital signal processors. The standard versions offer varying performance grades and temperature ranges. The SE model specifically targets the –55°C to +125°C operating range using a leadless ceramic chip carrier. The /883B suffix indicates compliance with MIL-STD-883, providing enhanced reliability for defense and aerospace applications compared to standard commercial parts.

Replacement Considerations

Direct replacements must match the 12-bit resolution, 100 kHz sampling rate, and DSP interface compatibility. Verify that alternative components support the same ±5 V supply configuration and FIFO architecture. Check if substitute packages maintain the necessary thermal and mechanical characteristics for the –55°C to +125°C range.