AD7228LPZ

Overview

The AD7228LPZ is an octal 8-bit digital-to-analog converter (DAC) fabricated on LC2MOS CMOS technology. It integrates eight voltage-mode DACs with output buffer amplifiers and interface logic on a single monolithic chip. The device features separate on-chip latches for each DAC, accessed via a common 8-bit parallel data bus controlled by A0, A1, and A2 address inputs and a WR signal. It operates from single or dual supplies, supporting VDD ranges of 10.8 V to 16.5 V and VSS of −5 V ± 10%. Key performance metrics include a settling time of 5 µs to ±1/2 LSB, total unadjusted error of ±1 LSB (L/C versions), and a maximum power dissipation of 1 W.

Feature Summary

• Octal architecture with eight independent 8-bit DACs and integrated output buffers.
• Microprocessor-compatible parallel interface with TTL/CMOS levels and individual latch control.
• Flexible supply operation: Single 5 V, single +15 V, or dual ±15 V configurations.
• LC2MOS process ensures high speed and linearity without requiring external user trims.

Applications

• Automated test equipment requiring programmable timing deskew.
• Multi-channel data acquisition systems needing coarse/fine voltage adjustment.
• Industrial control systems utilizing self-programmable reference circuits.

Procurement Notes

Verify the package type matches the application requirements, as the AD7228 family includes PDIP, CERDIP, SOIC, and PLCC variants. Confirm that the specific LPZ suffix corresponds to the 28-lead PLCC surface-mount package. Ensure that the design accounts for the absolute maximum ratings, particularly regarding power dissipation limits and ESD precautions during handling.

Selection Notes

Select the L or C version if tighter accuracy specifications are required, such as ±1 LSB total unadjusted error compared to ±2 LSB for K and B versions. Consider the 28-lead PLCC package only if surface-mount assembly is necessary, noting that pins 1, 8, 15, and 22 are not connected. Verify that the external reference source can handle the varying input impedance presented by the DAC array under different code conditions.

Part Context

The AD7228 series belongs to Analog Devices' LC2MOS octal DAC family, designed to reduce board space and increase reliability in multi-converter systems. The LPZ variant specifically denotes the 28-lead Plastic Leadless Chip Carrier (PLCC) package. This component serves as a versatile solution for applications requiring multiple synchronized analog outputs from a single digital interface.

Replacement Considerations

Direct replacements within the same package and pinout include other AD7228 grades such as AD7228LCZ or AD7228KCZ. For surface-mount applications requiring identical functionality, verify compatibility with the 28-lead PLCC form factor. Cross-referencing with quad DACs like the AD7226 requires significant circuit redesign due to channel count differences.