AD7228KR

Overview

The AD7228KR is an octal 8-bit digital-to-analog converter (DAC) fabricated on LC2MOS technology. It integrates eight voltage-mode DACs with output buffer amplifiers and interface logic on a single chip. The device features individual 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 V ± 10%) or a single 15 V supply. Key electrical parameters include a settling time of 5 µs for positive full-scale changes and 7 µs for negative changes in single-supply mode. Static performance specifies a total unadjusted error of ±2 LSB and differential nonlinearity of ±1 LSB.

Feature Summary

• Octal architecture with eight independent 8-bit DACs and integrated output buffers.
• Microprocessor-compatible parallel interface with TTL/CMOS levels and 95 ns write pulse support.
• Flexible power supply options including dual supplies (-5 V/+15 V) or single 5 V operation.
• No external trimming required for specified performance; guaranteed monotonicity.

Applications

• Automated test equipment requiring multi-channel signal generation.
• Industrial process control systems with multiple analog outputs.
• Programmable power supplies and waveform generators.
• Instrumentation requiring coarse/fine adjustment circuits.

Procurement Notes

Verify the 'K' suffix indicates the standard commercial grade version with ±2 LSB total unadjusted error. Confirm package availability matches design requirements, as the KR designation typically corresponds to specific leaded packages like PDIP or CERDIP. Check datasheet revision D for updated ordering information and absolute maximum ratings to ensure compatibility with system voltage limits.

Selection Notes

Select the AD7228KR when multiple isolated 8-bit channels are needed without external buffering components. Ensure the application can accommodate the 2 kΩ minimum load resistance per channel. For single-supply designs, verify that the negative settling time to near 0 V meets timing constraints, as it may be slower than dual-supply operation. Consider the 5 V single-supply variant if low power dissipation is critical, noting potential offset impacts.

Part Context

The AD7228 belongs to Analog Devices' LC2MOS family of high-speed CMOS DACs. The 'K' suffix denotes the standard performance grade, while other suffixes like 'B' or 'L' offer tighter accuracy specifications such as ±1 LSB total unadjusted error. The device replaces older bipolar DAC technologies by integrating precision analog and high-speed digital logic on a single monolithic chip.

Replacement Considerations

For higher accuracy requirements, consider the AD7228LB or AD7228KB variants which offer ±1 LSB total unadjusted error. The MX7228KCWG+ is a pin-compatible alternative from Maxim Integrated but operates in a SOIC-24 surface-mount package rather than through-hole. Verify pinout compatibility and thermal characteristics when substituting packages.