AD7858AN

Overview

The AD7858AN is a 12-bit, 200 kSPS successive approximation analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It operates from a single 3 V to 5.5 V supply and features eight single-ended or four pseudo-differential analog inputs. The device utilizes a CMOS SAR architecture with an internal 2.5 V reference and supports flexible serial interfaces including SPI and QSPI. Key electrical specifications include a typical signal-to-noise ratio of 70 dB, integral nonlinearity of ±1 LSB, and power dissipation of 20 mW at 5 V. It is housed in a 24-lead plastic dual-in-line package (DIP).

Feature Summary

• System and self-calibration capabilities with automatic calibration on power-up.
• Flexible serial interface compatible with 8051, SPI, QSPI, and microprocessor systems.
• Automatic power-down mode activated after conversion for low-power applications.
• Eight single-ended or four pseudo-differential input channels selectable via control register.

Applications

• Battery-powered personal digital assistants and mobile communications devices.
• Medical instruments requiring high-speed sampling with low power consumption.
• Pen computers and portable instrumentation systems.
• High-speed modems and industrial control systems.

Procurement Notes

Verify the specific suffix 'AN' corresponds to the 24-lead Plastic DIP package when sourcing. Confirm that the component meets the required temperature range of -40°C to +85°C. Ensure compatibility with the intended serial interface protocol before integration. Check for current availability status as manufacturing statuses may change.

Selection Notes

Select the AD7858AN over the AD7858L variant if a throughput rate of 200 kSPS is required, as the L version is limited to 100 kSPS. Consider the 24-lead DIP package constraints for PCB layout compared to SOIC or SSOP options. Evaluate power requirements against the 20 mW typical dissipation at 5 V operation. Verify that the 12-bit resolution and ±1 LSB linearity meet system accuracy needs.

Part Context

The AD7858AN belongs to the AD7858 family of high-speed, low-power 12-bit ADCs. This family includes variants optimized for speed (AD7858) and low power (AD7858L), available in DIP, SOIC, and SSOP packages. The AD7858 series is designed for battery-powered applications, offering system calibration and multiple power-down modes to extend battery life while maintaining accurate data acquisition.

Replacement Considerations

The AD7858BN is a pin-compatible alternative within the same package offering improved linearity error of ±1/2 LSB. For lower power requirements, the AD7858LANZ provides similar functionality but with a reduced maximum sampling rate of 100 kSPS. Verify interface timing and power specifications when substituting these parts.