AD7858BRZ

Overview

The AD7858BRZ is a high-speed, low-power 12-bit Analog-to-Digital Converter (ADC) manufactured by Analog Devices Inc. It operates from a single 3 V to 5.5 V supply and features an 8-channel multiplexer supporting eight single-ended or four pseudo-differential inputs. The device utilizes a Successive Approximation Register (SAR) architecture with a throughput rate of 200 kSPS. It includes system and self-calibration capabilities, automatic power-down modes, and a flexible serial interface compatible with SPI, QSPI, and 8051 microprocessors. The component is housed in a 24-lead SOIC package.

Feature Summary

• Integrated system and self-calibration with autocalibration on power-up for accurate operation over time and temperature.
• Flexible serial interface compatible with standard protocols including SPI, QSPI, and 8051 microprocessors.
• Multiple power management options including automatic power-down after conversion to minimize energy consumption.
• Supports eight single-ended or four pseudo-differential analog input channels via an internal multiplexer.

Applications

• Battery-powered systems such as personal digital assistants and mobile communications devices
• Medical instruments requiring precise signal acquisition
• Instrumentation and control systems
• High-speed modems

Procurement Notes

Verify the specific grade suffix 'B' corresponds to the required linearity specifications, typically ±1/2 LSB integral nonlinearity. Confirm the package variant matches the design requirements, as the BRZ designation indicates a lead-free 24-lead SOIC. Ensure compatibility with the target voltage range of 3 V to 5.5 V for both analog and digital supplies before integration.

Selection Notes

Select the AD7858BRZ when a 200 kSPS sampling rate is required alongside 12-bit resolution. Consider this part over the AD7858L if higher speed is prioritized over ultra-low power consumption. Verify that the serial interface timing meets the controller's clock constraints. Ensure the application supports the required calibration sequence duration during startup.

Part Context

The AD7858BRZ belongs to the AD7858 family of 12-bit SAR ADCs. It is distinguished from the AD7858L variant by its optimized speed, offering 200 kSPS compared to the L version's 100 kSPS. The 'R' suffix denotes the SOIC package, while 'Z' indicates RoHS compliance. This component serves as a versatile data acquisition solution for embedded systems requiring moderate resolution and speed.

Replacement Considerations

The AD7858ARZ is a direct pin-compatible alternative within the same family, differing primarily in the specified operating temperature range or initial linearity grades. Verify that any substitute maintains the 200 kSPS throughput and 24-lead SOIC footprint to ensure mechanical and electrical compatibility without redesigning the PCB layout.