CAT4238 is a DC/DC step-up converter produced by Catalyst Semiconductor, Inc. It supports a fixed switching frequency of 1MHz, drives LEDs, and has an output voltage of up to 38V. The efficiency is up to 87%, the current is less than 0.6mA, the output current is adjustable, and it supports soft start, overcurrent protection, open LED overvoltage protection, automatic shutdown UVLO protection, and thermal overload protection. SOT23-5 package
The CAT4238 is a fixed‑frequency (1 MHz) boost converter designed for driving up to ten high‑efficiency LEDs. It provides a constant current output with up to 87 % efficiency and a low quiescent ground current of 0.6 mA, making it suitable for battery‑powered applications such as portable media players and handheld devices.
The device includes multiple protection mechanisms: UVLO shuts down at 1.9 V, over‑voltage protection limits the output to 40 V, and thermal shutdown activates above 150 °C. LED current is set by an external resistor (R1) using the formula I_LED = 0.3 V / R1, and the part is offered in a thin SOT‑23‑5 package for space‑critical designs.
| Efficiency | Up to 87 % |
|---|---|
| Output Voltage (LED string) | Up to 38 V |
| Quiescent Current | 0.6 mA |
| Switching Frequency | 1 MHz |
| Maximum LED Current | 40 mA |
| UVLO Threshold | 1.9 V |
LED current is set by an external resistor R1 using the formula I_LED = 0.3 V / R1.