AD7945AN-B

Overview

The AD7945AN-B is a 12-bit multiplying digital-to-analog converter (DAC) from Analog Devices, designed for single-supply operation. It features a parallel interface with 12-bit data inputs and operates within a VDD range of +3.0 V to +5.5 V. The device guarantees ±1 LSB relative accuracy and ±0.9 LSB differential nonlinearity in biased mode. Key electrical parameters include a maximum gain error of ±4 LSB over the temperature range and a typical power dissipation of 5 mW. The component utilizes a segmented architecture with an R-2R ladder, offering fast settling times and low glitch impulse characteristics suitable for precision analog signal generation.

Feature Summary

• 12-bit resolution with ±1 LSB relative accuracy and ±0.9 LSB DNL in biased mode
• Parallel digital interface with active-low Chip Select (CS) and Write (WR) inputs
• Operates on a single +3.3 V to +5.5 V supply with internal biasing at 1.23 V
• Low power consumption with typical IDD of 5 μA in standby conditions

Applications

• Battery-powered instrumentation systems requiring low power consumption
• Laptop computer peripheral interfaces
• Upgrades for legacy 754x series DAC designs in 5 V environments

Procurement Notes

Verify the specific ordering suffix 'AN-B' corresponds to the Plastic DIP package (N-20) and the industrial temperature range (-40 °C to +85 °C). Confirm that the '+B' suffix indicates the Biased Mode specification variant, which differs electrically from the standard Normal Mode B-grade parts. Ensure compatibility with single-supply architectures utilizing the 1.23 V bias point.

Selection Notes

Select the AD7945AN-B when a parallel interface is required instead of the serial AD7943 or byte-oriented AD7948. This part is appropriate for applications needing single-supply operation with internal biasing, eliminating the need for dual supplies. Compare against the AD7945BN if Normal Mode (+5 V only) operation is sufficient, as the AN-B variant offers broader supply voltage flexibility for lower voltage systems.

Part Context

The AD7945AN-B belongs to the AD7943/AD7945/AD7948 family of 12-bit multiplying DACs. While the AD7943 uses a serial interface and the AD7948 uses an 8-bit byte interface, the AD7945 provides a full 12-bit parallel input path. The 'AN-B' designation specifically identifies the Plastic DIP package version optimized for Biased Mode single-supply applications, distinguishing it from the standard +5 V Normal Mode variants.

Replacement Considerations

Publicly confirmed substitutes include the AD7945BN for Normal Mode +5 V applications and the AD7945ARS-B for SSOP packaging. Direct pin-compatible replacements require matching the parallel interface and 12-bit resolution. Verify that any substitute supports the required ±1 LSB accuracy and single-supply biased mode operation.