文档介绍：CAT4238
High Efficiency 10 LED
Boost Converter
Description
The CAT4238 is a DC/DC step−up converter that delivers an
accurate constant current ideal for driving LEDs. Operation at a fixed
switching frequency of 1 MHz allows the device to be used with small
value external ceramic capacitors and inductor. LEDs connected in
series are driven with a regulated current set by the external resistor
5
R1. LED currents up to 40 mA can be supported over a wide range of 1
input supply voltages up to V, making the device ideal for
TSOT−23
battery−powered applications. The CAT4238 high−voltage output TD SUFFIX
stage is perfect for driving mid−size and large panel displays CASE 419AE
containing up to ten white LEDs in series.
LED dimming can be done by using a DC voltage, a logic signal, or
PIN CONNECTIONS
a pulse width modulation (PWM) signal. The shutdown input pin
1
allows the device to be placed in power−down mode with “zero” SW VIN
quiescent current.
In addition to thermal protection and overload current limiting, the GND
device also enters a very low power operating mode during “Open FB SHDN
LED” fault conditions. The device is housed in a low profile (1 mm
max height) 5−lead thin SOT23 package for space critical (Top View)
applications.
MARKING DIAGRAM
Features
• Drives High Voltage LED Strings (38 V)
•
Up to 87% Efficiency MUYM
• Low Quiescent Ground Current mA
• Adjustable Output Current
• 1 MHz Fixed Frequency Low Noise Operation MU = Specific Device Code
• Y = Production Year (Last Digit)
Soft Start “In−rush” Current Limiting M = Production Month (1−9, A, B, C)
• Shutdown Current Less than 1 mA
• Open LED Overvoltage Protection
• Automatic Shutdown at V (UVLO) ORDERING INFORMATION
• Thermal Overload Protection Device Package Shipping
• Thin SOT23 5−lead (1 mm Max Height) CAT4238TD−GT3 TSOT−23 3,000/
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS (Pb−Free) Tape & Reel
Green*
Compliant