AD7247ABRZ

Overview

The AD7247ABRZ is a dual 12-bit voltage-output digital-to-analog converter (DAC) from Analog Devices, packaged in a 24-lead SOIC. It integrates two DAC channels with on-chip output amplifiers and a Zener voltage reference. The device features a parallel interface structure accepting 12-bit data via separate Chip Select inputs for each DAC and a common Write input. Key electrical specifications include a typical settling time of 8 µs to within ±1/2 LSB, a relative accuracy of ±1 LSB maximum, and differential nonlinearity of ±0.9 LSB maximum. It operates from single or dual supplies ranging from +10.8 V to +16.5 V.

Feature Summary

• Dual 12-bit CMOS DAC architecture with integrated output amplifiers and internal 5 V reference.
• Parallel loading structure with independent Chip Select inputs (CSA, CSB) and common Write (WR) input.
• Configurable output voltage ranges: 0 V to +5 V, 0 V to +10 V (unipolar), and ±5 V (bipolar).
• Typical settling time of 8 µs and low power consumption of 165 mW in single supply mode.

Applications

• Interfacing with 8-bit or 16-bit microprocessors such as the Intel 8086 and Motorola 68000.
• DSP systems requiring direct memory-mapped connections, such as those using the ADSP-2101.
• Multi-channel signal generation where simultaneous updating of multiple converters is required.

Procurement Notes

Verify the package type corresponds to the 'R' suffix indicating a Small Outline (SOIC) package. Confirm the temperature grade 'B' covers the industrial range of -40°C to +85°C. Ensure the specific revision matches the design requirements, as interface logic and timing parameters may vary between versions. Check for moisture sensitivity level compliance if lead-free soldering processes are utilized.

Selection Notes

Select the AD7247ABRZ when a parallel interface with independent channel selection is preferred over the double-buffered structure of the AD7237A. This model is suitable for applications requiring a 12-bit resolution with ±1 LSB accuracy and bipolar output capabilities. Consider the power supply constraints, as specified performance requires voltages between +10.8 V and +16.5 V. Evaluate the need for the internal reference versus an external precision source based on system noise requirements.

Part Context

The AD7247ABRZ belongs to the AD7237A/AD7247A family of enhanced DACPORT devices. It serves as the parallel-interface counterpart to the AD7237A, which utilizes an 8-bit wide data bus with a double-buffered structure. Both parts share the same monolithic CMOS fabrication process, offering space savings and reliability improvements over multi-chip designs. The family supports operation from 12 V to 15 V supplies with improved interface speeds.

Replacement Considerations

The AD7237ABRZ is a functional alternative within the same family but requires a different interface protocol due to its 8-bit data bus and double-buffered latch structure. Direct pin-for-pin replacement is possible, but software or firmware must be updated to handle the two-step write sequence and LDAC control signals specific to the AD7237A.