LM3421/LM3423 are versatile high voltage LED driver controllers, ideal for a wide range of applications.
The LM3421 and LM3423 are versatile high‑voltage LED driver controllers that can be configured for buck, boost, buck‑boost (flyback) or SEPIC topologies. They operate from 4.5 V to 75 V input and include a high‑voltage startup regulator, adjustable switching frequencies up to 2.0 MHz, and a range of protection features such as over‑voltage lock‑out, under‑voltage lock‑out, and thermal shutdown.
The document provides detailed pin descriptions, absolute maximum ratings, electrical characteristics, typical performance curves, and physical dimensions for the TSSOP‑16 EP (MXA16A) and TSSOP‑20 EP (MXA20A) packages. Ordering information, application examples, and design notes are also included.
| Input voltage range | 4.5 V to 75 V |
|---|---|
| Internal reference voltage | 1.235 V (typical) |
| Current sense voltage | Adjustable from 20 mV |
| Maximum switching frequency | Up to 2.0 MHz |
| Shutdown current | < 1 pA |
| Package (LM3421) | TSSOP‑16 EP (MXA16A) |
| Package (LM3423) | TSSOP‑20 EP (MXA20A) |
The devices operate from 4.5 V up to 75 V.
They have a 1.235 V internal reference voltage (typical).
LM3421 is offered in a TSSOP‑16 EP (MXA16A) package, and LM3423 in a TSSOP‑20 EP (MXA20A) package.
The internal PWM controller can be set up to 2.0 MHz.