AD7904BRU

Overview

The AD7904BRU is an 8-bit, 4-channel successive approximation analog-to-digital converter (ADC) housed in a 16-lead TSSOP package. It operates from a single 2.7 V to 5.25 V supply with a maximum throughput rate of 1 MSPS. The device features four single-ended inputs managed by a channel sequencer and supports SPI/QSPI/MICROWIRE/DSP compatible serial interfaces. Power consumption reaches a maximum of 13.5 mW at 5 V supplies and 6 mW at 3 V supplies during operation. Key performance metrics include a signal-to-noise ratio of 49 dB minimum, integral nonlinearity of ±0.2 LSB maximum, and differential nonlinearity of ±0.2 LSB maximum.

Feature Summary

• Integrated channel sequencer for automated sequential conversion of four single-ended inputs.
• Flexible power management with full shutdown mode reducing current to 0.5 µA maximum.
• VDRIVE function allows the serial interface to operate independently of the analog supply voltage.
• No pipeline delays ensure accurate control of sampling instants via the CS input.

Applications

• Battery-powered equipment requiring low power consumption.
• Data acquisition systems with multiple single-ended sensor inputs.
• Industrial process control applications.
• Medical instrumentation.

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm package type and temperature range specifications. Ensure that the external reference voltage and supply rails match the required operating conditions for the desired performance levels. Confirm compatibility with the target microprocessor or DSP serial interface protocols before integration.

Selection Notes

Select this component when an 8-bit resolution and 1 MSPS throughput are sufficient for the application requirements. Consider the AD7914 or AD7924 if higher resolution (10-bit or 12-bit) is needed. Evaluate the power dissipation constraints to determine if the normal or shutdown modes meet the system's energy efficiency goals. Ensure the available serial clock frequency supports the required conversion time.

Part Context

The AD7904BRU belongs to the AD7904/AD7914/AD7924 family of high-speed, low-power ADCs from Analog Devices. This family shares identical pinouts, functional blocks, and interface protocols, differing primarily in resolution and dynamic performance specifications. The B version denotes the commercial temperature range variant (-40°C to +85°C), while the W version is qualified for automotive applications.

Replacement Considerations

Direct replacements within the same family include the AD7914BRU (10-bit) and AD7924BRU (12-bit). These parts maintain pin compatibility but offer different resolutions and noise performance characteristics. Verify that the increased resolution does not exceed the system's processing bandwidth or alter the required reference voltage stability.