AD7945BNZ

Overview

The AD7945BNZ is a 12-bit multiplying digital-to-analog converter (DAC) from Analog Devices, featuring a parallel interface and housed in a 20-lead Plastic DIP package. It operates on a single +5 V supply with guaranteed specifications including ±0.5 LSB integral nonlinearity (INL) and differential nonlinearity (DNL). The device delivers low power consumption of typically 5 mW and fast settling times of 600 ns to 0.01% when used with an AD843 amplifier. It supports normal mode operation at +4.5 V to +5.5 V and includes a current output architecture suitable for high-speed applications.

Feature Summary

• 12-bit resolution with ±0.5 LSB max INL and DNL accuracy
• Parallel data interface with active-low Chip Select (CS) and Write (WR) inputs
• Low power consumption: typically 5 μA supply current (5 mW typ)
• Fast settling time: 600 ns to 0.01% with AD843 output amplifier
• Low glitch impulse: 60 nV-s typical with amplifier connected

Applications

• Battery-powered instrumentation systems
• Laptop computer peripheral interfaces
• Direct upgrades for industry-standard AD7545 designs

Procurement Notes

Verify the component grade matches the required temperature range; the 'B' suffix indicates industrial grade (-40°C to +85°C). Confirm the package type corresponds to the N-20 designation for the 20-lead Plastic DIP. Ensure the design utilizes a +5 V supply, as this specific variant is optimized for Normal Mode operation rather than the Biased Mode found in '-AN-B' versions.

Selection Notes

Select the AD7945BNZ when a parallel interface is preferred over serial or byte-oriented alternatives within the AD794x family. This part is suitable for designs requiring superior speed and lower power compared to legacy AD7545 devices. Verify that the system can accommodate the 20-pin DIP footprint and that the digital logic levels meet the specified VINH/VINL requirements for the +5 V supply rail.

Part Context

The AD7945BNZ belongs to the AD7943/AD7945/AD7948 family of fast 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. These devices are designed to replace older AD754x series components, offering improved performance metrics while maintaining pin compatibility for many existing 5 V designs.

Replacement Considerations

The AD7945BNZ serves as a direct drop-in replacement for the AD7545 in 5 V designs. When substituting, ensure the output amplifier configuration supports the faster settling characteristics and verify that the parallel data bus timing meets the new setup and hold time requirements.