AD7228LP

Overview

The AD7228LP is an octal 8-bit voltage-mode digital-to-analog converter (DAC) fabricated on LC2MOS technology. It integrates eight DACs with output buffer amplifiers and interface logic on a single chip, eliminating the need for external trims. The device features individual latches for each channel, controlled via a common 8-bit parallel data bus and address inputs (A0-A2). It supports both single-supply (13.5 V to 16.5 V) and dual-supply (VDD: 10.8 V to 16.5 V; VSS: -5.5 V to -4.5 V) operation. Key electrical specifications include a settling time of 5 µs for positive full-scale changes and 7 µs for negative full-scale changes in single-supply mode, with a maximum power dissipation of 1 W.

Feature Summary

• Octal architecture with eight independent 8-bit DACs and integrated output buffers.
• LC2MOS process ensures high speed and linearity without user trimming.
• Microprocessor-compatible interface with TTL/CMOS levels and 95 ns write pulse support.
• Flexible supply options including single 5 V, single 15 V, or dual ±5 V configurations.

Applications

• Automated test equipment requiring timing deskew capabilities.
• Industrial control systems utilizing coarse/fine adjustment circuits.
• Multi-channel signal generation where board space optimization is critical.

Procurement Notes

Verify the specific suffix 'LP' against the manufacturer's current ordering guide, as legacy designations may indicate obsolete packages or grades. Confirm package availability (PDIP, CERDIP, SOIC, or PLCC) matches the target PCB layout requirements. Check for RoHS compliance status if environmental regulations apply to the end product.

Selection Notes

Select the AD7228LP when multiple isolated DAC channels are required within a single footprint. Ensure the application can provide the necessary reference voltage range (2 V to 10 V) and that the load resistance meets the minimum 2 kΩ requirement. Consider the 7 µs negative settling time if operating in single-supply mode near ground potential.

Part Context

The AD7228 belongs to Analog Devices' LC2MOS family of octal DACs. The 'L' grade typically denotes improved accuracy specifications compared to the 'K' grade, while the 'P' suffix indicates a plastic package variant. This component serves as a foundational building block for multi-channel analog output systems before the prevalence of serial-interface DACs.

Replacement Considerations

Direct pin-for-pin replacements include other AD7228 variants such as AD7228KNZ or AD7228ACPZ, provided the package type (e.g., PDIP-24 vs. PLCC-28) is compatible. Verify that the replacement part maintains the same L-grade accuracy specifications and settling time characteristics.