AD7840JN

Overview

The AD7840JN is a complete 14-bit CMOS 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 DSPs like the ADSP-2100. 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 76 dB and total harmonic distortion of -78 dB max at 1 kHz.

Feature Summary

• Complete 14-bit voltage output DAC with integrated 3 V reference and buffer amplifier
• Dual interface capability: Parallel mode with 21 ns setup time; Serial mode up to 6 MHz clock
• Bipolar output range of ±3 V with 14-bit resolution
• Low power consumption: Typically 70 mW at ±5 V supplies

Applications

• Direct interfacing with high-speed DSP processors such as ADSP-2100 and TMS320 series
• Speech synthesis systems requiring precise waveform generation
• Servo control applications needing fast settling times
• High-speed modem signal generation

Procurement Notes

Verify the suffix 'JN' corresponds to the Plastic DIP-24 package and the commercial temperature range of 0°C to +70°C. Confirm that the part number matches the Rev B datasheet specifications for SNR and nonlinearity. Ensure compatibility with ±5 V supply rails and 3 V reference input requirements during integration.

Selection Notes

Select the AD7840JN when a 14-bit resolution with ±3 V output swing is required. Choose this model over the KN variant if a minimum SNR of 76 dB and INL of ±2 LSB are acceptable. Verify that the system can provide ±5 V supplies. Consider the PLCC package (AD7840JP/KP) if surface mount technology is preferred over the through-hole DIP-24 format.

Part Context

The AD7840 belongs to Analog Devices' family of complete voltage output DACs. The JN suffix specifically denotes the commercial grade version housed in a 24-pin plastic dual-in-line package. Other variants in the series include the KN for higher accuracy, and A/B grades for industrial temperature ranges. The device utilizes LC2MOS process technology combining bipolar precision with CMOS low power.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.