AD7880BR

Overview

The AD7880BR is a monolithic 12-bit analog-to-digital converter (ADC) fabricated in Analog Devices' LC2MOS process. It operates from a single +5 V supply and features a throughput rate of 66 kHz, achieved through a 12 μs conversion time and a 3 μs on-chip track/hold amplifier. The device includes versatile interface logic with three-state data outputs and supports multiple input ranges: 0 V to +5 V, 0 V to +10 V, and ±5 V. Power consumption is 25 mW in normal operation and reduces to 2 mW in power save mode. It provides a signal-to-noise ratio of 70 dB minimum and total harmonic distortion of -80 dB typical.

Feature Summary

• Supports three user-selectable analog input ranges including unipolar and bipolar configurations using a single +5 V supply.
• Integrates a fast track/hold amplifier and successive-approximation architecture for high-speed signal acquisition.
• Features low power dissipation with a dedicated power save mode suitable for battery-operated systems.
• Provides direct interfacing capability to microprocessors and digital signal processors via standard control inputs.

Applications

• Battery powered portable systems
• Digital signal processing
• Speech recognition and synthesis
• High speed modems
• Control and instrumentation

Procurement Notes

Verify the specific suffix 'R' corresponds to the SOIC package variant when sourcing. Confirm that the B version specifications regarding full-scale and zero errors align with system requirements. Ensure proper handling precautions are observed due to electrostatic sensitivity. Validate that the external clock frequency matches the 2.5 MHz requirement for optimal performance.

Selection Notes

Select this component for applications requiring 12-bit resolution at moderate sampling rates up to 66 kHz. Consider the available input range options to match the signal source without external attenuation. Evaluate the power budget to determine if the power save mode is necessary for extended battery life. Ensure the host processor can accommodate the parallel data bus and control timing requirements.

Part Context

The AD7880 series comprises industrial grade variants designed for general-purpose data acquisition. The BR designation specifically indicates the small outline integrated circuit package option within the broader family. This part belongs to a line of low-power, single-supply converters intended for cost-sensitive embedded applications.

Replacement Considerations

Direct substitutes include other AD7880 variants such as AD7880BN or AD7880CN depending on the required package type and accuracy class. Verify pin compatibility and electrical specifications before substitution.

FAQ

How is the reference voltage typically connected for specified performance?

For specified performance, the reference input should be tied to VDD. The part can operate with a reference down to 2.5 V, though performance may degrade.

What determines the start of the conversion cycle?

The conversion cycle is initiated on the rising edge of the CONVST pulse, which places the track/hold amplifier into hold mode.

Can the AD7880 handle bipolar signals with a single supply?

Yes, the internal resistor network allows the part to accept bipolar input signals (±VREF) while operating from a single +5 V supply.