System Power Supply for TV Series FET Controller Type 3ch System Power Supply ICs No.09034EAT03 BD8621EFV Description BD8621EFV has realized the high performance and reliability required as a power supply for thin-screen TV. With built-in FET 1ch current mode control, the DC/DC Converter series has the advantage of high-speed load response and wide phase margin. Due to the high-speed load response, it is most suitable for TV-purpose processors with increasingly high performance, and due to the wide phase margin it leaves a good margin for board pattern & constant setting and so facilitates its application design. As a high-reliability design, it has various built-in protection circuits (overcurrent protection, output voltage abnormal protection, thermal protection, and off-latch function at the time of abnormality etc.), therefore as an advantage it does not easily damage in every possible abnormal condition such as all-pin short circuit test etc. and hence most suitable for thin-screen TV which requires the high reliability. Features 1) 3A output current 2) Low RDS(ON) internal switches (PchMOS:75mNchMOS:55m ) 3) 1% reference voltage accuracy 4) Programmable frequency : 250kHz-1MHz 5) (Frequency in programmable by adjusting RT resistance or synchronizing with SYNCLK terminal.) 6) Terminal RT OPEN/SHORT detecting function 7) Over current protection function 8) Output over voltage/low voltage protection function (over : FB > VREF +60mV , low : FB < VREF -60mV) 9) Timer off latch function in abnormal circumstances 10) Thermal shutdown function 11) Under voltage protection 12) Soft start/start delay circuit 13) Soft start time out function 14) Protecting BUS function with terminal PDET 15) HTSSOP-B20 package www.rohm.com 2009.05 - Rev.A 1/14 2009 ROHM Co., Ltd. All rights reserved. Technical Note BD8621EFV Electrical characteristics (Unless otherwise noted Ta=25, VIN=3.3V, GND=0V) Specification value Parameter Symbol UNIT Condition MIN TYP MAX VIN supply current (operating) I - 220 350 A V = 0.83V, V = 1V Q active FB FC VIN supply current (standby) I - 0 1 A V = 0V Q stby EN Reference voltage (VREF) V 0.792 0.8 0.808 V REF 60 mV Monitoring FB Output rise detection voltage V 30 90 OVP terminal -60 mV Monitoring FB Output decrease detection voltage V -90 -30 LVP terminal Terminal PDET output current I 0.4 - - mA V < 0.3V PDET PDET Oscillation frequency f 500 550 600 kHz R = 220k OSC RT Pch FET ON resistance R - 75 110 m I = 1A PFET SW Nch FET ON resistance R - 55 90 m I = 1A NFET SW UVLO voltage V 2.35 2.50 2.65 V UVLO SW leak current I - 0 1 A V = 0V, V = 5.5V LSW EN IN EN terminal H threshold voltage V 1.1 - - V ENH EN terminal L threshold voltage V - - 0.4 V ENL FC sink current I 10 20 - A FCSI FC source current I - -20 -10 A FCSO SS/DELAY terminal source current I 2 4 6 A SSSO Terminal PDET pull-up resistor R 100 170 250 k PDET V :FB terminal voltage, V :EN terminal voltage, V :FC terminal voltage, V : PDET terminal voltage FB EN FC PDET Current capability should not exceed Pd. www.rohm.com 2009.05 - Rev.A 2/14 2009 ROHM Co., Ltd. All rights reserved.