MB3821

FUJITSU SEMICONDUCTOR DATA SHEET DS04-27221-2E ASSP For Power Supply Applications With Power Mode Switching Function 2-ch DC/DC Converter IC With Synchronous Rectifier MB3821 s DESCRIPTION The MB3821 is a pulse width modulation (PWM) type 2-channel DC/DC converter IC with synchronous rectification designed for low voltage, high efficiency operation in high precision and high frequency applications, ideal for down conversion. A normal/low-power mode selection is provided, ideal for an internal power supply (3.3V, 5V) in applications with substantial load current variation, such as notebook computers. s FEATURES Synchronous rectification High efficiency : 93 % (normal power mode, VIN = 6 V, load 1 A) : 84 % (low power mode, VIN = 6 V, load 20 mA) Built-in power mode selector circuit Reference voltage accuracy : 2.5V ± 2 % Built-in error amp input control type soft start circuit Totem pole type output for N-ch MOSFET applications Built-in timer-latch type short protection circuit s PACKAGE 24-pin, Plastic SSOP (FPT-24P-M03) MB3821 s PIN ASSIGNMENT (TOP VIEW) CT : 1 RT : 2 GND : 3 CS1 : 4 IN −IN1 : 5 FB1 : 6 24 : VREF 23: VCC 22 : CSCP 21 : CS2 20 : −IN2 19 : FB2 18 : CTL 17 : OUT1−2 16 : VS2 15 : CB2 14: OUT2−2 13 :VB IN (CH1) SEL : 7 OUT1−1 : 8 VS1 : 9 CB1 : 10 OUT2−1 : 11 GND(0) : 12 (CH2) OUT OUT (FPT-24P-M03) 2 MB3821 s PIN DESCRIPTION Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Symbol CT RT GND CS1 –IN1 FB1 SEL OUT1...