AD7858BR

Overview

The AD7858BR is a high-speed, low-power 12-bit analog-to-digital converter (ADC) from Analog Devices Inc. It operates on a single 3 V to 5.5 V supply and supports throughput rates up to 200 kSPS. The device features an internal SAR architecture with eight single-ended or four pseudo-differential analog inputs. It includes system and self-calibration capabilities to maintain accuracy over temperature and time. The ADC utilizes a flexible serial interface compatible with SPI, QSPI, and 8051 protocols. Power consumption is typically 20 mW at 5 V and 12 mW at 3 V in normal mode, with automatic power-down options available.

Feature Summary

• Integrated self-calibration and system calibration functions ensure long-term accuracy without external components.
• Flexible serial interface supports multiple communication protocols including SPI, QSPI, and 8051 modes.
• Configurable input multiplexer allows selection between eight single-ended or four pseudo-differential channels.
• Automatic power-down mode activates after conversion to minimize energy usage in battery-operated applications.

Applications

• Battery-powered portable systems such as personal digital assistants and mobile communications devices
• Medical instrumentation requiring precise signal acquisition
• Pen computers and handheld data collection terminals
• Industrial instrumentation and control systems

Procurement Notes

Verify the specific suffix BR indicates the SOIC-24 package variant when sourcing replacements. Confirm that the B grade specification meets the required integral nonlinearity tolerance of ±1/2 LSB for the target application. Ensure the operating voltage range aligns with the 3 V to 5.5 V supply requirements specified in the datasheet.

Selection Notes

Select the AD7858BR over the AD7858L variant if the application requires the higher 200 kSPS sampling rate rather than the 100 kSPS limit of the low-power version. Consider the B grade specifications for tighter linearity errors compared to the A grade. Evaluate the power dissipation requirements against the thermal impedance characteristics of the SOIC-24 package for the intended ambient temperature conditions.

Part Context

The AD7858 series comprises CMOS successive approximation ADCs designed for speed and low power. The AD7858BR specifically denotes the B grade performance level housed in a 24-lead Small Outline Integrated Circuit (SOIC) package. This component belongs to a family that includes the lower-power AD7858L variant and different packaging options such as DIP and SSOP.

Replacement Considerations

The AD7858ARZ is a documented parameter-equivalent substitute offering similar functionality in a tube package. Verify pin compatibility and electrical specifications before substitution. Other variants within the AD7858 family may require adjustments to calibration settings or power management configurations.