AD7920BRMZ

Overview

The AD7920BRMZ is a 12-bit successive approximation analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It operates from a single power supply ranging from 2.35 V to 5.25 V and supports throughput rates up to 250 kSPS. The device features an internal track-and-hold amplifier capable of handling input frequencies exceeding 13 MHz. Power consumption is specified at 4.2 mW maximum at 3 V and 15 mW maximum at 5 V during operational mode, with a full power-down current of 1 μA maximum. The component utilizes a flexible serial interface compatible with SPI, QSPI, Microwire, and DSP standards.

Feature Summary

• Integrated reference derived directly from the power supply voltage eliminates the need for external components.
• Flexible power management allows conversion rate adjustment via serial clock speed to optimize efficiency.
• Standard successive approximation architecture ensures no pipeline delays in data output.

Applications

• Battery-powered systems
• Medical instruments
• Data acquisition systems

Procurement Notes

Verify the specific grade (B Grade) and package variant against the official datasheet ordering guide before procurement. Confirm that the B Grade specifications align with the required accuracy metrics for the intended application. Ensure compatibility with the system's logic voltage levels, particularly when operating near the lower supply voltage limits.

Selection Notes

Select this component for applications requiring high resolution and low power consumption within a compact footprint. Consider the internal reference derivation when designing the power supply network, as noise on VDD directly impacts ADC performance. Evaluate the trade-off between throughput rate and power dissipation based on the available serial clock frequency.

Part Context

This part belongs to the AD7910/AD7920 family of high-speed, low-power ADCs. While the AD7910 offers 10-bit resolution, the AD7920 provides 12-bit precision. Both share identical pinouts and functional characteristics, differing primarily in resolution and associated linearity specifications. The BRMZ suffix indicates the commercial temperature range and MSOP-8 packaging.

Replacement Considerations

The AD7910BRMZ serves as a lower-resolution alternative within the same package and family. Other 12-bit SAR ADCs may require significant circuit redesign due to differences in reference architecture, pinout, or serial interface protocols.

FAQ

How is the ADC reference voltage determined?

The reference is derived internally from the VDD power supply, allowing the widest dynamic input range without requiring an external reference component.

What is the impact of the serial clock speed on power consumption?

The conversion rate is determined by the serial clock; increasing the clock speed reduces conversion time, which allows for reduced average power consumption when utilizing the power-down mode between conversions.

Does the device introduce pipeline delays?

No, the AD7920 uses a standard successive approximation architecture with accurate control of the sampling instant via the CS input, resulting in no pipeline delays.