AD7948BN

Overview

The AD7948BN is a 12-bit multiplying digital-to-analog converter (DAC) featuring an 8-bit byte interface. It operates from a single +5 V supply in Normal Mode, with guaranteed specifications including ±0.5 LSBs integral and differential nonlinearity. The device utilizes a segmented architecture with R-2R ladder switches for current steering. Key electrical parameters include a typical power dissipation of 5 mW, a reference input resistance of 6 kΩ to 12 kΩ, and a write pulsewidth of 40 ns at +5 V. It provides low glitch impulse performance of 60 nV-s and fast settling times when paired with appropriate output amplifiers.

Feature Summary

• 12-bit resolution with ±0.5 LSB max INL and DNL
• 8-bit byte interface with CSMSB, CSLSB, WR, and LDAC control signals
• Low power consumption: 5 mW typical at +5 V supply
• Fast digital interface with 40 ns minimum write pulsewidth

Applications

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

Procurement Notes

Verify the specific ordering suffix 'BN' corresponds to the 20-lead Plastic DIP package and the B Grade temperature range of –40 °C to +85 °C. Confirm that the application requires the 8-bit byte interface variant rather than the serial or full parallel versions within the AD7943/AD7945 family. Ensure supply voltage constraints align with the Normal Mode +5 V specification for this grade.

Selection Notes

Select the AD7948BN when an 8-bit microcontroller interface is preferred over serial or full parallel connections. This model is suitable for applications requiring a single +5 V supply and industrial temperature operation. For single-supply biased mode operation (+3.3 V to +5 V), the AN-B suffix variants must be selected instead, as they are specifically tested for biased conditions with different accuracy grades.

Part Context

The AD7948 is part of the Analog Devices AD7943/AD7945/AD7948 family of fast 12-bit multiplying DACs. While the AD7943 offers a serial interface and the AD7945 provides a 12-bit parallel bus, the AD7948 specifically implements an 8-bit byte-oriented interface. All three share identical core DAC architecture and performance metrics but differ in digital input logic and pin configurations to suit various system bus architectures.

Replacement Considerations

The datasheet identifies the AD7948 as a direct replacement for the industry-standard AD7548 in 5 V designs. Designers should verify that the legacy AD7548 pinout matches the AD7948N DIP/SOP/SSOP configurations. Performance improvements include lower power consumption and faster settling times compared to the older generation component.