降压型直流电源变换器芯片(常规型) XL1507

Features
􀂄 Wide 4.5V to 40V Input Voltage Range
􀂄 3.3V,5V,12V, and adjustable versions
􀂄 Output Adjustable from 1.23V to 37V
􀂄 Maximum Duty Cycle 100%
􀂄 Minimum Drop Out 1.5V
􀂄 Fixed 150KHz Switching Frequency
􀂄 3A Constant Output Current Capability
􀂄 Internal Optimize Power Transistor
􀂄 High efficiency
􀂄 Excellent line and load regulation
􀂄 TTL shutdown capability
􀂄 ON/OFF pin with hysteresis function
􀂄 Built in thermal shutdown function
􀂄 Built in current limit function
􀂄 Built in second current limit function
􀂄 Available in TO-252 package
Applications
􀂄 LCD Monitor and LCD TV
􀂄 Digital Photo Frame
􀂄 Set-up Box
􀂄 ADSL Modem
􀂄 Telecom / Networking Equipment
General Description
The XL1507 is a 150 KHz fixed frequency
PWM buck (step-down) DC/DC converter,
capable of driving a 3A load with high
efficiency, low ripple and excellent line and
load regulation. Requiring a minimum
number of external components, the regulator
is simple to use and include internal
frequency compensation and a
fixed-frequency oscillator.
The PWM control circuit is able to adjust the
duty ratio linearly from 0 to 100%. An enable
function, an over current protection function
is built inside. When second current limit
function happens, the operation frequency
will be reduced from 150KHz to 50KHz. An
internal compensation block is built in to
minimize external component count.
Figure1. Package Type of XL1507 (TO252-5L)