AD667BD

Overview

The AD667BD is a microprocessor-compatible, complete voltage output 12-bit digital-to-analog converter (DAC) manufactured by Analog Devices. It integrates a high-stability buried Zener voltage reference and double-buffered input latch on a single chip. The device utilizes precision bipolar current steering switches and a laser-trimmed thin-film resistor network to achieve fast settling times and high accuracy. Key electrical specifications include a maximum settling time of 4 μs to ±0.01% for full-scale range changes with a 10 kΩ feedback resistor. It operates with dual power supplies ranging from ±11.4 V to ±16.5 V, drawing typical supply currents of 8 mA and 20–25 mA for positive and negative rails respectively. The component is housed in a 28-lead Ceramic DIP package.

Feature Summary

• Complete 12-bit DAC function with guaranteed monotonicity over the operating temperature range.
• Integrated high-stability buried Zener voltage reference requiring no external components.
• Double-buffered input latch architecture prevents spurious analog output values during data updates.
• TTL/5 V CMOS compatible logic inputs with low logic input currents.

Applications

• Microprocessor-based control systems requiring precise analog signal generation.
• Industrial process control loops utilizing ±12 V or ±15 V supply rails.
• Test and measurement equipment needing stable, low-drift voltage references.

Procurement Notes

Verify the specific grade requirements against the ordering guide, as linearity and temperature coefficient specifications vary between J, K, A, B, and S models. Confirm that the application supports the required ±12 V or ±15 V dual power supply configuration. Ensure the PCB layout accommodates the 28-lead Ceramic DIP footprint and adheres to the grounding rules specified in the datasheet to minimize noise coupling between analog and digital sections.

Selection Notes

Select the AD667BD when a ceramic package is required for environments demanding higher thermal stability than plastic variants. This model offers a maximum linearity error of ±1/4 LSB at +25°C and a temperature coefficient of 15 ppm/°C, suitable for applications requiring tighter accuracy than the AD667AD. Verify that the system can accommodate the physical dimensions of the CDIP-28 package and that the interface logic matches the TTL/CMOS input levels defined in the specifications.

Part Context

The AD667 series comprises several grades differentiated by temperature range and accuracy. The AD667BD belongs to the 'B' grade, offering improved linearity (±1/4 LSB max) and lower drift (15 ppm/°C) compared to the 'J' and 'A' grades. It shares the same core architecture and pinout with other variants like the AD667AD and AD667SD but is optimized for commercial/industrial temperature ranges (-25°C to +85°C).

Replacement Considerations

Direct functional replacements within the same family include the AD667AD (Ceramic DIP, -25°C to +85°C, ±1/2 LSB linearity) and AD667SD (Ceramic DIP, -55°C to +125°C, ±1/2 LSB linearity). For plastic package equivalents, consider the AD667KNZ or AD667JPZ, noting differences in thermal performance and package material.