SGS-Thomson L4922 free download

File name L4922.pdf

L4922 . . . . . . . VERY LOW DROP REGULATOR WITH RESET VERY LOW DROP (max. 0.9 V at 1 A) OVER FULL OPERATING TEMPERATURE RANGE (­ 40 / + 125°C) LOW QUIESCENT CURRENT (max 70 mA at 1 A) OVER FULL T RANGE PRECISE OUTPUT VOLTAGE (5 V ± 4 %) OVER FULL T RANGE POWER ON-OFF INFORMATION WITH SETTABLE DELAY REVERSE BATTERY PROTECTION SHORT CIRCUIT PROTECTION THERMAL SHUTDOWN Pentaw att ORDERING NUMBER : L4922 DESCRIPTION The L4922 is a high current monolithic voltage regulator with very low voltage drop (0.70 V max at 1 A, TJ = 25 °C). The device is internally protected against load dumps transient of + 60V, reverse polarity, over- heatingand output short circuit : thanks toted for the automotive and industrial applications. BLOCK DIAGRAM October 1991 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. 1/6 L4922 ABSOLUTE MAXIMUM RATINGS Symbol Vi Vr VD TJ T op Tstg DC Input Voltage DC Reverse Voltage Positive Load Dump Protection (t = 300ms) Junction Temperature Range Operating Temperature Range Storage Temperature Range Parameter Value 35 ­18 60 ­40 to 150 ­40 to 125 ­55 to 150 Unit V V V °C °C °C Note: The circuit is ESD protected according to MIL-STD-883C THERMAL DATA Symbol Rth j-case Parameter Thermal Resistance Junction-case Max. Value 3.5 Unit °C/W PIN CONNECTION (Top view) FUNCTIONAL DESCRIPTION The operating principle of the voltage regulator is based on the reference, the error amplifier, the driver and the power PNP. This stage uses an Isolated Collector Vertical PNP transistor which allows to obtain very low dropout voltage (typ. 450mV) and low quiescentcurrent (IQ = 20mAtypically atIo = 1A). Thanks to these features the device is particularly suited when the power dissipation must be limited as, for example, in automotive or industrial applications supplied by battery. The three gain stages (operational amplifier, driver and power PNP) require the external capacitor (Comin = 22µF) to guarantee the global stability of the system. The antisaturationcircuit allows to reduce drastically the current peak which takes place during the start up. The reset function is LOW active when the output voltage level is lower than the reset threshold voltage VRthOFF (typ.value : Vo ­150mV). When the output voltage is higher than VRthON the reset becomes HIGH after a delay time settablewith the externalcapacitor Cd. Typically td = 20ms, Cd = 0.1µF. The reset and delay threshold hysteresis improve the noise immunity allowing to avoid false switchings. The typical reset output waveform is shown in fig. 1. 2/6 L4922 ELECTRICAL CHARACTERISTICS (Vi = 14. 4V, ­ 40°C TJ + 125°C unless otherwise specified) Symbol Vi Vo VLine SVR Parameter Operating Input Voltage Output Voltage Line Regulation Supply Voltage Rejection Test Conditions (*) Note 1 Io = 0mA to 1A TJ = 25°C Vi = 6 to 26V; IO = 10mA Io = 700mA f = 120Hz; Co = 47µF Vi = 12Vdc + 5Vpp Io = 10mA to 1A TJ = 25°C