LIA136S

Overview

The LIA136S is a low voltage optically isolated error amplifier from IXYS Integrated Circuits Division, designed for precision feedback in power supply applications. It integrates a precision shunt reference, an error amplifier, and an NPN phototransistor optocoupler into a single surface-mount package. The device operates with an input voltage range of 1.6V to 10V over the temperature range of -40°C to +110°C. Key electrical characteristics include a reference voltage of 1.299V with ±1.5% accuracy across the operating temperature range and a high common mode transient immunity of 20V/ns. The current transfer ratio ranges from 500% to 2000%, ensuring robust signal transmission across the isolation barrier.

Feature Summary

• Integrates a precision programmable shunt reference, error amplifier, and optocoupler in a single package
• Features reduced dark current at high temperatures compared to standard variants
• Provides enhanced common mode transient immunity for noisy environments
• Operates down to a minimum input voltage of 1.6V for low voltage designs

Applications

• Low voltage power supply feedback loops
• Isolated AC-to-DC power supply regulation
• DC-to-DC converter control circuits
• Flyback converter secondary side regulation

Procurement Notes

Verify the specific suffix 'S' confirms the surface mount package type required for your PCB layout. Ensure the design accounts for the thermal dissipation limits specified in the absolute maximum ratings table. Confirm that the operating temperature range meets the environmental requirements of the final assembly. Check for any updated manufacturing notices regarding component availability or packaging changes.

Selection Notes

Select the LIA136S when high common mode transient immunity is critical for system stability. Choose this part over the LIA135 if operation at elevated temperatures up to 110°C is required due to its optimized dark current performance. Consider the surface mount footprint constraints during the initial schematic capture phase. Evaluate the need for base pin access if external compensation networks are necessary for specific loop dynamics.

Part Context

The LIA136 belongs to the LIA135/LIA136 family of low voltage optically isolated error amplifiers manufactured by IXYS Integrated Circuits Division. These devices serve as functional equivalents to discrete precision shunt regulators combined with optocouplers. The series is specifically engineered to simplify feedback circuitry in isolated power supplies by reducing component count and board space requirements while maintaining high accuracy and reliability.

Replacement Considerations

Official substitute part numbers are not explicitly confirmed in the provided datasheet documentation. Designers should consult the manufacturer directly for validated cross-reference information. Verify pin compatibility and electrical specifications before attempting any substitution. Ensure that any alternative component meets the same isolation voltage and thermal performance standards.

FAQ

What is the primary difference between the LIA135 and LIA136?

The LIA136 features reduced dark current at high temperatures and provides an accessible base pin (Pin 2) for the output phototransistor, whereas the LIA135 has a higher common mode transient immunity rating but lacks the external base connection.

How does the LIA136 handle common mode transients?

The LIA136 offers a common mode transient immunity of 20V/ns. This can be further enhanced by placing a capacitor in parallel with a resistor connected between the base and emitter pins to shunt transient currents away from the base-emitter junction.

What is the function of Pin 2 on the LIA136?

Pin 2 is the base of the internal NPN phototransistor. It allows users to connect external components, such as a resistor to the emitter, to reduce dark current at high temperatures or improve immunity to common mode transients.