AD7888ARUZ

Overview

The AD7888ARUZ is a micropower, 12-bit successive-approximation analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It features eight single-ended analog inputs and operates from a single 2.7 V to 5.25 V power supply. The device supports throughput rates up to 125 kSPS with a full-power bandwidth of 2.5 MHz. It integrates an on-chip 2.5 V reference or accepts external references between 1.2 V and VDD. The ADC utilizes a serial interface compatible with SPI, QSPI, Microwire, and DSP standards. It is housed in a 16-lead TSSOP package and includes flexible power management options such as automatic shutdown after conversion.

Feature Summary

• Integrates an 8-channel multiplexer with a track-and-hold amplifier for single-ended signal acquisition.
• Features a versatile serial interface compatible with multiple standard protocols including SPI and Microwire.
• Includes an internal 2.5 V voltage reference that can be disabled for external reference applications.
• Offers flexible power management modes including normal operation, standby, and automatic shutdown.

Applications

• Battery-powered systems such as personal digital assistants and mobile communications devices.
• Medical instruments requiring low power consumption and high resolution.
• Instrumentation and control systems utilizing multi-channel data acquisition.
• High-speed modem applications requiring fast throughput rates.

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to ensure correct packaging and temperature grade. Confirm that the component meets all required environmental standards for the intended deployment environment. Cross-reference the datasheet revision to ensure compatibility with existing design specifications and pin configurations.

Selection Notes

Select this component when designing systems that require an 8-channel multiplexed input within a compact 16-lead package. Ensure the application voltage range falls between 2.7 V and 5.25 V. Consider the power management modes if battery life is critical, as automatic shutdown reduces average power consumption significantly during idle periods between conversions.

Part Context

The AD7888ARUZ belongs to the AD7888 series of micropower ADCs from Analog Devices. It shares functional similarities with other members of the family but differs in package type, with the ARUZ suffix denoting the 16-lead Thin Shrink Small Outline Package (TSSOP). This package offers a smaller footprint compared to the SOIC variant while maintaining identical electrical performance characteristics.

Replacement Considerations

The AD7888ARZ serves as a direct replacement option, offering identical electrical specifications but packaged in a 16-lead Narrow SOIC format instead of TSSOP. Verify mechanical clearance and soldering profile requirements before substituting packages.

FAQ

How is the analog input channel selected for conversion?

The analog input channel is selected using the ADD0, ADD1, and ADD2 bits in the Control Register. These bits determine which of the eight single-ended inputs (AIN1 through AIN8) is routed to the track-and-hold amplifier for the next conversion sequence.

What is the function of the REF IN/REF OUT pin?

This pin provides access to the on-chip 2.5 V reference for external use. Alternatively, it allows the user to apply an external reference voltage ranging from 1.2 V to VDD. When an external reference is applied, the internal reference should be disabled via the Control Register for optimal performance.

How does the automatic shutdown mode operate?

In Autoshutdown mode, the AD7888 automatically enters full shutdown at the end of each conversion cycle to minimize power consumption. The device wakes up upon the first falling edge of the serial clock after chip select deassertion, allowing for efficient power management in intermittent sampling applications.