NCR421PASX

Overview

The NCR421PASX is a constant current LED driver IC manufactured by Nexperia, housed in an SOT-1118 (HUSON6) surface-mount package. It integrates an NPN transistor with two diodes on a single chip to provide stabilized output current without requiring external resistors for the base configuration. The device supports a supply voltage up to 40 V and features a digital PWM input for dimming control at frequencies up to 10 kHz. Key electrical parameters include a maximum collector-emitter voltage of 40 V, continuous collector current of 250 mA, and power dissipation of 530 mW. It operates within a temperature range of -55 °C to +150 °C.

Feature Summary

• Integrates an NPN transistor and two diodes on one chip for simplified circuit design
• Provides stabilized output current without the need for external base resistors
• Supports digital PWM input for dimming applications up to 10 kHz frequency
• Features low voltage overhead to maximize efficiency in LED driving

Applications

• Automotive interior lighting systems
• Dashboard and instrumentation illumination
• Number plate lights
• Generic constant current sources

Procurement Notes

Verify the specific suffix 'X' against the official Nexperia datasheet to confirm reel packaging specifications and tape-and-reel dimensions. Ensure the ordering part number matches the exact package variant required for your PCB footprint. Cross-reference the RoHS compliance status and any automotive qualification marks such as AEC-Q101 if applicable to your design requirements.

Selection Notes

Select this component when a compact solution for constant current LED driving is needed without external biasing resistors. The integrated PWM capability makes it suitable for dimmable automotive lighting applications. Consider the 530 mW power dissipation limit and the 40 V maximum voltage rating to ensure compatibility with the target LED string configuration and operating environment.

Part Context

This device belongs to the NCR series of LED drivers from Nexperia, which are designed to reduce component count and board space. Unlike discrete solutions, these integrated drivers combine active components on a single die. The SOT-1118 package offers a small form factor suitable for space-constrained designs, distinguishing it from larger packages like SOT223 used in other variants of the same functional family.

Replacement Considerations

Check for direct substitutes within the NCR series, such as the NCR420PAS or NCR421Z, ensuring package compatibility and electrical parameter alignment. Verify that alternative parts support the required PWM input functionality and current stabilization characteristics before substitution.