AD7840JPZ-REEL

Overview

The AD7840JPZ-REEL 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 DSPs like the ADSP-2100. It operates from ±5 V supplies, delivering a bipolar output range of ±3 V with a typical power dissipation of 70 mW. Key dynamic specifications include a signal-to-noise ratio of 78 dB min and settling time within 1/2 LSB in typically 2 μs.

Feature Summary

• Complete 14-bit voltage output DAC with on-chip 3 V reference and buffer amplifier
• Dual interface capability: 14-bit parallel mode with 21 ns setup time or serial mode up to 6 MHz clock
• Bipolar output range of ±3 V with 80 dB SNR and -80 dB THD max
• Low power consumption of 70 mW typ. operating from ±5 V supplies

Applications

• Direct interfacing with high-speed DSP processors such as ADSP-2100 and TMS320 series
• Servo control systems requiring fast update rates and monotonicity
• Speech synthesis and high-speed modem applications
• Precision data acquisition systems utilizing external sample-and-hold circuits

Procurement Notes

Verify the 'JPZ' suffix indicates the 28-terminal plastic leaded chip carrier (PLCC) package variant. Confirm the specific grade (J vs K) regarding Signal-to-Noise Ratio (78 dB vs 80 dB min) and Integral Nonlinearity (±2 LSB vs ±1 LSB max) requirements for the design. Ensure the ordering code matches the required temperature range and performance tier specified in the manufacturer's ordering guide.

Selection Notes

Select the AD7840KPZ variant if higher precision is required, offering 80 dB min SNR and ±1 LSB max INL compared to the J version's 78 dB and ±2 LSB. For serial interface designs, ensure the microprocessor supports the required 16-bit data stream format and synchronization signals. Verify that the load capacitance does not exceed 50 pF without adding a series resistor to maintain stability of the internal reference and output buffer.

Part Context

The AD7840 belongs to Analog Devices' LC2MOS family of complete DACs, combining precision bipolar circuits with low-power CMOS logic. It is functionally related to other 14-bit converters like the AD7535 but distinguishes itself with integrated buffering and dual interface modes. The PLCC packaging provides a compact surface-mount solution suitable for dense PCB layouts in industrial and communication equipment.

Replacement Considerations

The AD7840KN serves as a higher-performance alternative with improved linearity and SNR. For quad-channel applications, the AD7834 or AD7836 may be considered, though they differ in channel count and interface specifics. Direct pin-compatible replacements are limited; verify timing parameters and supply voltage compatibility when substituting.