AD7840KP

Overview

The AD7840KP is a complete 14-bit voltage output digital-to-analog converter (DAC) fabricated in LC2MOS technology. It integrates a 14-bit DAC, a 3 V buried Zener reference, an output amplifier, and high-speed control logic. The device supports both parallel and serial interfaces, enabling direct connection to high-speed DSP processors like the ADSP-2100 and TMS320 series. It operates from ±5 V supplies with typical power dissipation of 70 mW. The analog output provides a bipolar range of ±3 V. Key dynamic specifications include a minimum signal-to-noise ratio of 80 dB and total harmonic distortion of -80 dB. The part is housed in a 28-terminal plastic leaded chip carrier (PLCC) package.

Feature Summary

• Complete 14-bit voltage output DAC with integrated 3 V reference and output buffer
• Dual interface capability: Parallel mode with 21 ns setup time and Serial mode with 6 MHz clock rate
• High dynamic performance: 80 dB SNR and -80 dB THD at 1 kHz
• Low power consumption: Typically 70 mW at ±5 V supplies

Applications

• Direct interfacing with high-speed DSP processors such as ADSP-2100, TMS32010, and TMS32020
• Speech synthesis systems requiring fast data update rates
• Servo control applications needing precise voltage generation
• High-speed modem signal generation

Procurement Notes

Verify the ordering suffix 'P' corresponds to the PLCC-28 package and 'K' indicates the commercial temperature range (0°C to +70°C). Confirm RoHS compliance status as historical documentation may vary. Ensure supply voltage rails are strictly maintained within ±5% of ±5 V for specified performance. Check for ESD sensitivity precautions during handling.

Selection Notes

Select the AD7840KP when a 14-bit resolution with ±3 V output swing is required. Choose this model over the JN variant if a surface-mount PLCC package is preferred. Ensure the application requires the commercial temperature range; select the SQ or BQ variants for industrial or extended temperature ranges. Verify that the system can provide the necessary ±5 V dual supplies.

Part Context

The AD7840 is part of Analog Devices' LC2MOS family of complete DACs. The KP suffix specifically denotes the Plastic Leaded Chip Carrier (PLCC) package with 28 pins and the K grade for commercial temperature operation. It shares functional similarities with the AD7840JN but differs in packaging. Other family members include quad DACs like the AD7834 and sampling ADCs like the AD7871.

Replacement Considerations

Publicly confirmed substitutes include the AD7840KN (same function, DIP package) and AD7840JP (same function, PLCC package, lower SNR). Cross-family replacements require verifying pin compatibility and electrical specifications against the original design requirements.