AD693AD

Overview

The AD693AD is a monolithic signal conditioning circuit designed for loop-powered 4–20 mA sensor transmitters. It accepts low-level inputs from transducers and controls a standard two-wire current loop. The device features an instrumentation amplifier front end, a V/I converter, and a 6.2 V reference with up to 3.5 mA excitation current capability. Total unadjusted error is less than 0.5% of full scale at +25°C and 0.75% over the -40°C to +85°C industrial temperature range. Nonlinearity is under 0.05%. It supports precalibrated input spans of 30 mV or 60 mV via pin strapping and offers output spans of 4–20 mA, 0–20 mA, or 12 ± 8 mA. The component is housed in a 20-pin ceramic side-brazed DIP package.

Feature Summary

• Monolithic integration of instrumentation amplifier, voltage-to-current converter, and precision reference for complete signal conditioning.
• Loop-powered operation allows transducer excitation using the internal 6.2 V reference without external power sources.
• Laser-trimmed thin-film resistors provide high accuracy with precalibrated input and output spans, minimizing calibration needs.
• Provision for an external pass transistor to off-load power dissipation, reducing self-heating errors and extending operational reliability.

Applications

• Process control systems requiring standardized 4-20 mA transmission.
• Factory automation environments utilizing bridge or RTD sensors.
• System monitoring applications involving pressure transducers.

Procurement Notes

Verify the specific suffix 'AD' corresponds to the Ceramic Side-Brazed DIP (D-20) package when sourcing. Confirm that the required operating temperature range aligns with the industrial specification of -40°C to +85°C. Ensure the application design accounts for the maximum operational voltage limits and current capabilities defined in the datasheet specifications.

Selection Notes

Select this model for applications requiring a complete, low-level voltage-to-current loop conditioner. It is suitable for replacing discrete designs in process control and factory automation. Consider the external pass transistor option if minimizing self-heating errors is critical for maintaining accuracy in high-power dissipation scenarios.

Part Context

The AD693 series includes variants such as the AD693AQ in Cerdip and AD693AE in LCCC packages. All variants share identical electrical characteristics and functionality, differing primarily in physical packaging. The AD693AD specifically denotes the ceramic side-brazed DIP configuration, offering robust mechanical stability for industrial environments.

Replacement Considerations

Discrete designs previously used for similar signal conditioning tasks can be replaced by this integrated circuit. No direct equivalent part numbers are listed in the provided documentation; verify compatibility with existing board layouts and pin configurations when substituting.