AD7908BRU

Overview

The AD7908BRU is an 8-bit, high-speed, low-power successive approximation analog-to-digital converter featuring eight single-ended inputs and a built-in channel sequencer. It operates from a single 2.7 V to 5.25 V supply with throughput rates up to 1 MSPS. The device includes a wide bandwidth track-and-hold amplifier capable of handling input frequencies exceeding 8 MHz. Power consumption reaches a maximum of 6 mW at 3 V and 13.5 mW at 5 V during full operation. It utilizes a flexible serial interface compatible with SPI, QSPI, MICROWIRE, and DSP standards.

Feature Summary

• Eight single-ended analog inputs managed by a programmable channel sequencer for automated multi-channel conversion sequences.
• VDRIVE function enables the serial interface logic levels to operate independently of the analog supply voltage, supporting direct connection to 3 V or 5 V processors.
• Flexible power management allows conversion rate adjustment via serial clock speed and offers auto-shutdown modes to minimize current draw at lower throughput rates.
• Standard successive approximation architecture ensures no pipeline delays, providing accurate control of the sampling instant via the CS input.

Applications

• Industrial process control systems requiring multi-channel data acquisition
• Battery-powered instrumentation utilizing low power consumption features
• Automotive sensor interfaces meeting automotive qualification standards

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm package type and temperature range. Confirm that the B version meets the required -40°C to +85°C operating specifications. Ensure the external reference voltage is set to 2.5 V ±1% for optimal performance compliance. Check for automotive grade variants if extended temperature ranges are necessary.

Selection Notes

Select this component when an 8-bit resolution is sufficient for the application's accuracy requirements. Consider the AD7918 or AD7928 if higher resolution (10-bit or 12-bit) is needed while maintaining similar pinouts and functionality. Evaluate the power supply constraints, as the device supports both 3 V and 5 V operations with corresponding power dissipation differences.

Part Context

The AD7908 belongs to the AD7908/AD7918/AD7928 family of 8-, 10-, and 12-bit ADCs from Analog Devices. These devices share identical pin configurations and functional blocks, differing primarily in resolution and associated dynamic performance metrics like SINAD and SNR. This family is designed for applications requiring multiple channels with moderate speed and low power consumption.

Replacement Considerations

The AD7908BRUZ is a tube-packaged equivalent of the BRU variant. The AD7908BRU-REEL and AD7908BRU-REEL7 are reel-packaged versions of the same electrical specification. Verify that any substitute maintains the 20-lead TSSOP package and 8-bit resolution compatibility.