General Description
In order to enhance the efficiency performance, the
LD5523K integrates the multi-mode PWM controller,
which consists of Quasi-Resonant (QR) PWM control for
light load condition and Continue Conduction Mode
(CCM) for heavy load condition. Moreover, the QR
controller not only gains the system performance, but
also brings the worse EMI capability, while the
frequency swapping function of LD5523K can reduce
the EMI emission of SMPS and helps the power circuit
designers to simply deal with EMI filter and saves
several component and developing time.
The LD5523K is implemented in SOT-26 package, and
includes the comprehensive protection function, such as
Over Load Protection (OLP), Over Voltage Protection
(OVP), Output Short Circuit Protection (OSCP) and
internal Over Temperature Protection (OTP).
Furthermore, the programmable brown-in/out and bulk
cap. OVP protection is built-in.

Features
 Secondary-side feedback control with
quasi-resonant + CCM operation
 Low Startup Current (<1A)
 0.285mA Ultra-low operating current at light load
 Current Mode Control with Cycle-by-Cycle Current
Limit
 Green Mode Control
 UVLO (Under Voltage Lockout)
 LEB (Leading-Edge Blanking) on CS Pin
 VCC OVP (Over Voltage Protection)
 Adj. OVP / UVP on FB pin
 Adj. BNI/BNO, Bulk cap. OVP on FB pin
 OLP (Over Load Protection)
 External OTP (Over Temperature Protection) on
CS Pin
 Internal OTP (Over Temperature Protection)
 SDSP (Secondary Diode Short Protection)
 Gate Source/Sink Capability: 350mA/-355mA @
output pin with 33nF capacitor.

Applications
 Switching AC/DC Adaptor