AD7845JRZ

Overview

The AD7845JRZ is a complete 12-bit multiplying digital-to-analog converter (MDAC) with an integrated output amplifier, fabricated on Analog Devices' LC2MOS process. It features full 4-quadrant multiplication capability and includes three on-chip application resistors for gain ranging and offset adjustment. The device utilizes a parallel interface compatible with TTL and 5 V CMOS logic. Key electrical specifications include a maximum settling time of 5 µs to 0.01% of full-scale range, a typical glitch impulse of 5 nV-s, and a unity gain small-signal bandwidth of 600 kHz. It operates within a temperature range of 0°C to +70°C and is housed in a 24-lead SOIC package.

Feature Summary

• Integrated 12-bit CMOS MDAC with on-chip output amplifier providing full 4-quadrant multiplication.
• Includes three matched on-chip application resistors (RA, RB, RC) for simplified gain ranging and offset adjustment.
• Guaranteed monotonic operation across the specified temperature range with ±1 LSB relative accuracy at +25°C.
• Parallel digital interface with TTL and 5 V CMOS compatibility, featuring standard CS and WR control signals.

Applications

• Automatic Test Equipment
• Programmable Power Supplies
• Digital Attenuators
• Programmable Gain Amplifiers
• Digital-to-4–20 mA Converters

Procurement Notes

Verify the specific suffix 'JRZ' corresponds to the commercial temperature grade (0°C to +70°C) and the 24-lead SOIC package variant. Confirm that the ordering documentation specifies the plastic SOIC form factor rather than ceramic or DIP options available in the broader AD7845 family. Ensure compliance with RoHS directives as indicated in current manufacturer listings.

Selection Notes

Select the AD7845JRZ when a 12-bit resolution with integrated buffering and 4-quadrant multiplying functionality is required. This model is suitable for applications needing on-chip resistors for gain scaling, reducing external component count. Consider the 5 µs settling time and 600 kHz bandwidth for dynamic signal processing needs. Verify that the parallel interface requirements align with the host microprocessor system's data bus architecture.

Part Context

The AD7845 series represents Analog Devices' first 4-quadrant multiplying DAC with an on-chip amplifier. The JRZ designation specifically identifies the commercial grade version packaged in a 24-lead Small Outline Integrated Circuit (SOIC). This part belongs to a family offering various temperature ranges and package types, including DIP and LCC variants, allowing designers to choose based on thermal and spatial constraints.

Replacement Considerations

The MX7845JR-T from Maxim Integrated is a functional equivalent offering similar 12-bit multiplying DAC specifications in a comparable SOIC package. Designers should verify pinout compatibility and ensure that the alternative device meets the specific settling time and linearity requirements of the original design.