AD7840JPZ

Overview

The AD7840JPZ 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, and a high-speed output amplifier. The device supports both parallel and serial interface modes, allowing direct connection to DSPs and microprocessors. 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 signal-to-noise ratio of 78 dB minimum and total harmonic distortion of -80 dB maximum. The part is housed in a 28-lead plastic leaded chip carrier package.

Feature Summary

• Complete 14-bit DAC with on-chip 3 V reference and buffered output amplifier
• Dual interface capability: 14-bit parallel or 16-bit serial data loading
• High-speed performance: 45 ns minimum write pulse width and 21 ns data setup time
• Dynamic performance: 78 dB SNR and -80 dB THD at 1 kHz

Applications

• Direct interfacing with high-speed DSP processors such as ADSP-2100 and TMS320 series
• Generation of AC signals and DC voltages requiring 14-bit accuracy
• Servo control systems and speech synthesis applications
• High-speed modem signal generation

Procurement Notes

Verify the specific suffix JPZ corresponds to the 28-lead Plastic Leaded Chip Carrier (PLCC) package with commercial temperature range (0°C to +70°C). Confirm that the J grade specifies a minimum Signal-to-Noise Ratio of 78 dB and Integral Nonlinearity of ±2 LSB. Ensure supply voltages are maintained within ±5% of nominal ±5 V for specified performance.

Selection Notes

Select the AD7840JPZ when a 14-bit resolution with integrated reference and buffer is required. Choose this model over the KN variant if the application tolerates 78 dB SNR instead of 80 dB. Verify interface requirements; use parallel mode for setups under 21 ns or serial mode for clock rates up to 6 MHz. Ensure the load capacitance does not exceed 50 pF without a series resistor to maintain stability.

Part Context

The AD7840 belongs to Analog Devices' family of complete voltage output DACs. It utilizes LC2MOS technology, combining precision bipolar circuits with low-power CMOS logic. The device is functionally similar to other members like the AD7845 and AD7846 but offers distinct 14-bit resolution and specific interface timing characteristics suited for older DSP architectures.

Replacement Considerations

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