特性 Features

? Wide output range: up to 10 series LEDs

? Integrated 40V high current switch (800mA

limit)

? High efficiency PWM converter (up to 90)

? Low 200mV feedback voltage

? High accuracy across full load range

? VIN range: 2.7V to 5.5V

? LED open-circuit (OVP) protection

? KTD251: 36V

? KTD251B: 24V

? KTD251C: 19V

? High switching frequency

? KTD251: 900kHz

? KTD251B/C: 1.1MHz

? PWM dimming frequency: 100Hz to 200kHz

? Simple, small solution size

? Integrated Soft-start

? Shutdown Current less than 1μA

? Small TSOT23-6 Package

? RoHS and Green compliant

? -40°C to +85°C Temperature Range

Applications

? LED backlighting

? Mobile Phones

? Handheld Devices

? Digital Photo Frames

? Automotive Navigation

Brief Description

The KTD251 is a versatile constant current LED driver with

a high efficiency DC-DC step up “boost” converter

architecture. The low-side power MOSFET is integrated in

the device, minimizing the total number of external

components. Unique technology and high 800mA current

limit allow KTD251 to drive up to 36V output (10 LEDs in

series), up to 24V using KTD251B (6 LEDs in series) or up

to 19V using KTD251C (5 LEDs in series). Alternatively,

KTD251 can deliver 160mA total current with 3 series

LEDs per string. It can also maximize the current capability

while achieving high conversion efficiency. The optimized

0.9MHz and 1.1MHz switching frequencies result in small

external component size. The driver allows a wide range of

PWM dimming frequencies through the EN pin.

Various protection features are built into the KTD251,

including cycle-by-cycle input current limit protection, LED

open-circuit (output over voltage) protection and thermal

shutdown protection. The leakage current in shutdown

mode is less than 1μA.

The KTD251 is available in a RoHS compliant 6-lead

TSOT23 package.