AD7847AN

Overview

The AD7847AN is a complete, dual, 12-bit multiplying digital-to-analog converter (MDAC) with integrated output amplifiers. It utilizes an LC2MOS monolithic CMOS process and requires no external user trims for full specified performance. The device features two independent DAC channels with internal feedback resistors, eliminating the need for external components in standard configurations. It operates on dual power supplies ranging from ±14.25 V to ±15.75 V. Key static performance metrics include a relative accuracy of ±1 LSB maximum and a differential nonlinearity of ±1 LSB maximum, ensuring monotonic operation across the specified temperature range.

Feature Summary

• Dual 12-bit MDACs with integrated buffered voltage outputs
• Internal feedback resistors simplify circuit design
• Parallel loading structure with separate Chip Select inputs for each channel
• R-2R ladder architecture with segmented MSB decoding

Applications

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

Procurement Notes

Verify the specific suffix 'AN' corresponds to the Plastic DIP (N-24) package option as defined in the ordering guide. Confirm that the required operating temperature range aligns with the Industrial specification (-40 °C to +85 °C). Ensure supply voltages remain within the ±14.25 V to ±15.75 V limits to maintain guaranteed linearity specifications.

Selection Notes

Select the AD7847AN when a parallel interface with independent chip select lines for each DAC channel is required. This model differs from the AD7837 series, which uses an 8-bit bus interface with address lines A0/A1 and a common LDAC input. The AD7847 allows simultaneous or independent updating via the WR signal edge without a dedicated LDAC pin, simplifying microprocessor interfacing for 16-bit data buses.

Part Context

The AD7847 is part of the AD7837/AD7847 family of complete dual 12-bit multiplying DACs. While functionally similar to the AD7837, it distinguishes itself through its digital interface logic. The AD7847 employs a 12-bit latch per DAC with individual CSA and CSB inputs, whereas the AD7837 uses a split 8-bit/4-bit latch structure for 8-bit microprocessor compatibility. Both share the same core analog performance and R-2R architecture.

Replacement Considerations

The AD7847BN offers improved relative accuracy of ±1/2 LSB while maintaining the same N-24 package and interface. For applications requiring extended temperature ranges, the AD7847SQ provides operation from -55 °C to +125 °C in a Cerdip package. The AD7837AN is a functional alternative if an 8-bit bus interface with LDAC synchronization is preferred over the AD7847's parallel control scheme.