AD7880BN

Overview

The AD7880BN is a monolithic 12-bit successive-approximation analog-to-digital converter (ADC) operating from a single +5 V supply. It features a throughput rate of 66 kS/s, with a conversion time of 12 μs and an acquisition time of 3 μs. The device offers a signal-to-noise ratio (SNR) of 70 dB minimum and supports three user-selectable input ranges: 0 V to +5 V, 0 V to +10 V, and ±5 V. Power consumption is 25 mW in normal mode and 2 mW in power-down mode. It utilizes a parallel interface and is housed in a 24-pin plastic DIP package.

Feature Summary

• Supports multiple input ranges including unipolar and bipolar configurations using a single +5 V supply.
• Integrates a low-power control circuit for extended battery life in portable applications.
• Provides fast data access times suitable for direct interfacing with microprocessors and DSPs.

Applications

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

Procurement Notes

Verify the specific suffix 'BN' corresponds to the industrial temperature range (-40°C to +85°C) and the N-24 plastic DIP package option as defined in the ordering guide. Confirm that the B-version specifications, such as full-scale error and zero error tolerances, align with the design requirements before finalizing procurement.

Selection Notes

Select this component when a 12-bit resolution and 66 kHz sampling rate are required within a single +5 V supply system. Ensure the application can accommodate the parallel bus interface and the specific timing constraints associated with the CONVST and RD signals. Consider the thermal dissipation limits if operating at maximum ambient temperatures.

Part Context

The AD7880BN belongs to the AD7880 family of high-speed, low-power ADCs fabricated on Analog Devices' LC2MOS process. This technology combines precision bipolar circuits with low power CMOS logic to achieve specified performance levels without requiring external components other than decoupling capacitors and a clock source.

Replacement Considerations

The AD7880CN serves as a lower-error alternative within the same package and pinout configuration. Other variants include the AD7880BQ (cerdip), AD7880BR (SOIC), and their C-grade counterparts. Verify pin compatibility and electrical parameter differences before substitution.

FAQ

How does the AD7880 handle bipolar input signals?

The AD7880 accommodates bipolar inputs by connecting VINB to VREF while maintaining VINA as the primary signal input. This configuration allows for a ±VREF input range, typically ±5 V when VREF equals VDD.

What is the function of the MODE input pin?

The MODE input controls the power state of the device. Driving MODE to 0 V activates the power save mode, reducing power dissipation to approximately 2 mW. Connecting MODE to VDD enables normal operation.

Can the AD7880 operate without an external voltage reference?

Yes, the datasheet recommends tying the VREF input directly to VDD for specified performance. The device operates nominally with VREF equal to the +5 V supply voltage.