AD7837ARZ

Overview

The AD7837ARZ is a dual 12-bit monolithic digital-to-analog converter (DAC) featuring integrated output amplifiers, manufactured by Analog Devices Inc. It operates on ±15 V power supplies and delivers voltage outputs with a settling time of 3 µs to within ±1/2 LSB. The device utilizes a parallel interface structure designed for microprocessors with 8-bit data buses, employing separate least-significant and most-significant input latches updated via an asynchronous LDAC signal. Key static performance metrics include ±1 LSB relative accuracy and differential nonlinearity, ensuring monotonic operation across the industrial temperature range of -40°C to +85°C.

Feature Summary

• Dual 12-bit MDACs with integrated output amplifiers providing simultaneous analog updates via the LDAC pin.
• Parallel loading structure optimized for 8-bit microprocessor interfaces using A0/A1 address lines.
• High-speed performance with 3 µs typical settling time and 11 V/µs slew rate.
• ±1 LSB maximum relative accuracy and differential nonlinearity guaranteeing monotonicity.

Applications

• Automatic Test Equipment
• Function Generation and Waveform Reconstruction
• Programmable Power Supplies
• Synchro Applications

Procurement Notes

Verify the specific suffix 'R' confirms the SOIC-24 package variant. Confirm that the 'A' designation corresponds to the -40°C to +85°C industrial temperature range. Ensure compatibility with ±15 V supply requirements and check for ESD sensitivity handling during assembly.

Selection Notes

Select the AD7837ARZ when interfacing with 8-bit microcontrollers requiring parallel word loading. Choose this component over the AD7847 if independent chip select signals are not required and a simpler address-based latch control scheme is preferred. Verify that the external feedback resistor connection capability matches the circuit design, as the AD7837 requires external R_FB connections unlike the internally compensated AD7847.

Part Context

The AD7837ARZ belongs to the AD7837/AD7847 family of dual 12-bit DACs. While functionally similar in conversion resolution and speed, the AD7837 differs from the AD7847 by utilizing a parallel loading structure with shared Chip Select and Write inputs controlled by address lines A0 and A1, whereas the AD7847 uses individual chip selects for each channel.

Replacement Considerations

The AD7837BRZ offers the same package and interface but provides higher precision with ±1/2 LSB relative accuracy. The AD7847ARZ provides equivalent performance but features independent chip selects and internal feedback resistors, requiring schematic adjustments for replacement.

FAQ

How does the AD7837 handle data loading for its 12-bit channels?

The AD7837 uses a parallel loading structure where data is written to separate least-significant (8-bit) and most-significant (4-bit) input latches using address lines A0 and A1. Data is transferred to the DAC latches simultaneously when the LDAC pin is asserted low.

What is the maximum glitch impulse specified for the AD7837?

The Digital-to-Analog Glitch Impulse is specified at a maximum of 10 nV-seconds for a 1 LSB change around the major carry transition.

Can the AD7837 operate with reduced power supply voltages?

Yes, the device remains functional with supply voltages down to ±10 V without significant linearity degradation, though the output amplifier requires approximately 3 V of headroom from the supply rails to maintain accuracy.