AD7894ARZ-2REEL

Overview

The AD7894ARZ-2REEL is a 14-bit successive approximation analog-to-digital converter housed in an 8-lead SOIC package. It operates from a single +5 V supply and features an on-chip track/hold amplifier with a maximum conversion time of 5 µs. The device accepts a unipolar analog input range of 0 V to +2.5 V and utilizes a high-speed serial interface for data output. Typical power consumption is 20 mW, with a signal-to-noise ratio of 77 dB min at -40°C to +85°C.

Feature Summary

• Integrated on-chip track/hold amplifier supporting high sampling rates up to 160 kHz.
• High-speed two-wire serial interface allowing easy connection to microprocessors.
• Automatic power-down mode that activates after conversion to minimize energy usage.
• Pin-compatible design facilitating upgrades from 12-bit ADC solutions.

Applications

• Battery-powered portable instrumentation systems
• Industrial process control data acquisition
• Medical equipment requiring low-power signal digitization

Procurement Notes

Verify the specific suffix REEL indicates tape-and-reel packaging when sourcing components. Confirm the AD7894-2 designation matches the required 0 V to +2.5 V unipolar input range for the target application circuit. Ensure external reference voltage stability meets the specified minimum requirements for optimal accuracy.

Selection Notes

Select this component when a 14-bit resolution is required within a compact 8-lead footprint. The AD7894ARZ-2 variant is specifically designed for unipolar signals ranging from 0 V to +2.5 V. Consider the automatic power-down feature if battery life is a critical constraint in the system design.

Part Context

This part belongs to the AD7894 family of fast, 14-bit serial ADCs manufactured by Analog Devices. The family includes variants with different input ranges, such as bipolar options for ±10 V or ±2.5 V signals. The ARZ-2REEL designation specifies the industrial temperature range, lead-free RoHS-compliant construction, and reel packaging format.

Replacement Considerations

The datasheet identifies the AD7894 as a pin-compatible upgrade for the 12-bit AD7895. Designers migrating from older 12-bit architectures should verify that the increased resolution and updated timing characteristics align with their existing system constraints.

FAQ

What is the output coding format for the AD7894-2?

The AD7894-2 uses straight (natural) binary output coding, whereas the AD7894-10 and AD7894-3 use twos complement coding.

How does the automatic power-down mode function?

In Mode 2 operation, the device automatically enters power-down mode once the conversion is complete and BUSY goes low. It wakes up upon the rising edge of the CONVST signal before the next conversion cycle begins.

What is the maximum throughput rate achievable with this ADC?

With a serial clock frequency of 16 MHz, the AD7894 can achieve a throughput rate of up to 160 kHz, consisting of a 5 µs conversion time, 1.0 ms read time, and 250 ns quiet time.