KA78R33CTSTU

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The KA78R33CTSTU is a fixed positive low-dropout voltage regulator manufactured by onsemi, formerly Fairchild Semiconductor. It provides a stable 3.3V output with a maximum continuous current of 1A. The device utilizes a TO-220 full-mold package with four pins for through-hole mounting. Key electrical specifications include a maximum dropout voltage of 0.5V at full load and an input voltage range from 4V to 35V. It features line regulation of 2.5% and load regulation of 2%. The component operates within a temperature range of -20°C to +80°C and includes built-in protections such as thermal shutdown, overcurrent protection, and short-circuit protection.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Provides a fixed 3.3V output with 1A current capability in a TO-220-4 lead full mold package
• Features low dropout voltage performance below 0.5V at full rated current
• Includes comprehensive protection mechanisms: peak current protection, thermal shutdown, overvoltage protection, and output disable function

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• Constant voltage power sources for various electronic equipment
• Battery-powered systems requiring efficient voltage regulation
• Embedded systems needing stable 3.3V logic supply

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify the manufacturer origin carefully, as this part was originally produced by Fairchild Semiconductor before its acquisition by onsemi. Confirm the specific suffix CTSTU matches the required TO-220-4 full-mold package variant. Check for obsolescence status or lifecycle changes, as older Fairchild parts may have limited availability or be superseded by newer equivalents. Ensure compliance with RoHS directives if required for the target application.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this regulator when a fixed 3.3V output is required with up to 1A load current. It is suitable for applications where a low dropout voltage is critical for efficiency, particularly with battery supplies. The TO-220-4 package allows for easy heat dissipation compared to smaller surface-mount options. Consider the input voltage range (4V to 35V) to ensure adequate headroom for the desired dropout performance under all operating conditions.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

The KA78R33CTSTU belongs to the KA78RXXC series of low-dropout voltage regulators. This family offers fixed output voltages including 3.3V, 5V, 8V, 9V, 12V, and 15V. The series is characterized by its robust protection features and suitability for general-purpose power supply applications in consumer and industrial electronics. The TO-220-4 package provides a balance between power handling and ease of assembly.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

Direct substitutes include other 1A, 3.3V LDOs in TO-220 packages such as the LM340T-3.3 or similar variants from other manufacturers. Verify pinout compatibility, specifically the ground pin configuration in the TO-220-4 package, as some alternatives may differ. Ensure replacement components meet the same thermal and current protection requirements.