AD7228BQ

Overview

The AD7228BQ 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 chip. The device features separate latches for each channel, controlled via a common 8-bit parallel data bus and address inputs (A0-A2). It operates with dual supplies (VDD: 10.8 V to 16.5 V; VSS: -5.5 V to -4.5 V) or a single 5 V supply. Key electrical specifications include a settling time of 7 µs to ±1/2 LSB, a maximum power dissipation of 1 W, and operation within a temperature range of -40°C to +85°C.

Feature Summary

• Octal architecture containing eight independent 8-bit DACs with integrated output buffers.
• Microprocessor-compatible parallel interface with individual latch control via A0, A1, and A2 address lines.
• LC2MOS process enabling high-speed performance with 95 ns write pulse compatibility.
• Flexible power supply options supporting dual rails (±5 V nominal) or a single 5 V source.

Applications

• Automated test equipment requiring multi-channel signal generation.
• Industrial process control systems utilizing multiple analog outputs.
• Programmable power supply designs needing coarse/fine adjustment capabilities.
• Timing deskew circuits in high-speed digital systems.

Procurement Notes

Verify the specific suffix 'BQ' against the manufacturer's current ordering guide, as package availability and RoHS compliance may vary between production runs. Confirm that the required ceramic DIP package is still supported by the supplier, as legacy packages may have limited stock or discontinuation risks. Ensure the design accounts for the 1 W power dissipation limit and appropriate thermal management for the CDIP-14 footprint.

Selection Notes

Select the AD7228BQ when an application requires eight simultaneous 8-bit analog outputs from a single component. This part is suitable for systems needing TTL/CMOS compatible digital inputs and buffered voltage outputs capable of driving 2 kΩ loads. Consider the 7 µs settling time for dynamic applications and ensure the reference voltage remains within the 2 V to 10 V range for specified accuracy. Verify that the 24-lead CERDIP package fits the board layout constraints.

Part Context

The AD7228 series belongs to Analog Devices' family of octal CMOS DACs, designed to reduce board space and increase reliability compared to discrete solutions. The 'B' grade indicates tighter static performance specifications, such as ±1 LSB total unadjusted error, compared to lower grades. The 'Q' suffix typically denotes a qualified version for industrial or military temperature ranges, though specific qualification details should be confirmed in the latest datasheet revision.

Replacement Considerations

Direct pin-compatible replacements within the same package are limited due to the specific LC2MOS process and legacy packaging. Review the AD7228A or AD7228C variants for potential functional substitutes if looser accuracy specs are acceptable. For modern surface-mount alternatives, consider the AD56xx series or AD97xx RF DACs, though these require significant schematic and PCB redesign.