UTC UNISONIC TECHNOLOGIES CO. LTD 1 LINEAR INTEGRATED CIRCUIT MULTIFUNCTION VERY LOW DROP VOLTAGE REGULATOR DESCRIPTION FEATURES PIN CONNECTIONS DIP-8

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1 MULTIFUNION ERY LOW DROP OLTAGE REGULATOR DESCRIPTION The UTC L2949E is a monolithic integrated voltage regulator with a very low dropout output and additonal functions as power-on reset and input voltage sense.it is designed for supplying the microcomputer controlled systems especially in automotive applications. FEATU *Operating dc supply voltage range to 28. *Transient supply voltage up to 40. *Extremely low quiescent current in standby mode. *High precision standby output voltage ±1% *Output current capability up to 100. *ery low dropout voltage less than 0.. *Reset circuit sensing the output voltage *Programmable reset pulse delay with external capacitor *oltage sense comparator. *Thermal shutdown and short circuit protections. DIP-8 P-8 P-20 PIN CONNEIONS z z DIP-8/P P-20 UTC UNINIC TECHNOLOGIES CO. LTD 1

2 BLOCK DIAGRAM z PREREGULATOR 2μ REG 2 REF SENSE ABLUTE MAXIMUM RATINGS PARAMETER SYMBOL RATING UNIT DC Operating Supply oltage CC 28 Transient Supply oltage(t<1s) CC TR 40 Output Current Io Internally Limited Output oltage o 20 Output oltage Reset Output Sense Output Output Current Reset Output Sense Output Preregulator Output oltage z 7 Preregulator Output Current Iz Junction Temperature Tj -40~10 Storage Temperature Range Tstg -~10 so I Iso UTC UNINIC TECHNOLOGIES CO. LTD 2

3 THERMAL DATA DESCRIPTION SYMBOL RATING UNIT Thermal Resistance Junction-ambient DIP-8 P-8 P-20 Rth j-amb Thermal Resistance Junction-pin (P-20) Rth j-pins 1 /W Thermal Shutdown Junction temperature TJSD /W ELERICAL CHARAERISTICS(s=14;-40 <Tj<12 unless otherwise specified) Output oltage o Tj=2 ;Io= Output oltage o 6<IN<28,1<Io< Output oltage o IN=40; T<1s <Io< Dropout voltage D Io=10 Io=0 Io=100 Input to Output oltage Difference in Undervoltage Condition IO IN=4,Io=3 0.4 Max Output Leakage Iouth ** IN=2,o= μa Line Regulation OL 6<IN<28, Io=1 20 m Load Regulation OLO 1<Io< m Current Limit ILIM o=4. o=4.,tj=2 o=0(note 1) 100 Quiescent Current IQSE Io=0.3;TJ< μa Quiescent Current IQ Io=100 m ** With this test we guarantee that with no output current the output voltage will not exceed. Reset Thereshold oltage RT o-0. Reset Thereshold Hysteresis RTH m Reset Pulse Delay trd =100nF;TR 100μs ms Reset Output Low oltage RL R=10KΩ to s Reset Output Gigh Leakage Current IRH = 1 μa Delay Comparator Thereshold th 2 Delay Comparator Thereshold Hysteresis th,hy 100 m UTC UNINIC TECHNOLOGIES CO. LTD 3

4 SENSE Sense Low Thereshold st Sense Thereshold Hysteresis sth m Sense Output Low oltage L I 1.16;s Rso=10KΩ to o Sense Output Leakage ISH so=;i 1. 1 μa Sense Input Current I I= μa PREREGULATOR Preregulator Output oltage z Iz=10μA 4. 6 Preregulator Output Current Iz 10 μa Note 1:Foldback characteristic APPLICATION CIRCUIT z (optional) BAT PREREGULATOR 2μ REG 2 REF SENSE For stability:cs 1μF, Co 4.7μF, ESR<10Ωat 10KHz Recommended for application:cs=co=10µf to 100µF APPLICATION INFORMATION Suppl oltage Transient High supply voltage transients can cause a reset output signal disturbation. For supply voltage greater than 8 the circuit shows a high immunity of the reset output against supply transients of the reset output against supply transients of more than100/μs. For supply voltages less than 8 supply transients of more than 0.4/μs can cause a reset signal disturbation. To improve the transient behaviour for supply voltages less than 8 a capacitor at pin 3 can be used. A capacitor at pin 3(C3 1μF ) reduces also the output noise. UTC UNINIC TECHNOLOGIES CO. LTD 4

5 FUNIONAL DESCRIPTION The UTC L2949E is a monolithic integrated voltage regulator,based on the STM modular voltage regulator approch.several outstanding features and auxiliary functions are implemented to meet the requirements of supplying microprocessor systems in automotive applications.nevertheless,it is suitable also in other applications where the present functions are required.the modular approach of this device allows to get easily also other features and functions when required. oltage Regulator The voltage regulator uses an lsolated Collector ertical PNP transistor as a regulating element IOUT() Figure 1: Foldback Characteristic of o With this structure very low dropout voltage at currents up to 100 is obtained.the dropout operation of the standby regulator is maintained down to 3 input supply voltage.the output voltage is regulated up to the transient input supply voltage of 4.With this feature no functional interruption due to overvoltage pulses is generated.the typical cuve showing the standby.output voltage as a function of the input supply voltage is shown in Fig.2. The current consumption of the device(quiescent current) is less than 300μA. To reduce the quiescent current peak in the undervoltage region and to improve the transient response inthis region.the dropout voltage is controlled,the quiescent current as a function of the supply input voltage is shown in Fig.3. UTC UNINIC TECHNOLOGIES CO. LTD

6 IQ RL=100Ω s 40 Figure 2: Output oltage vs.input voltage 0. 0 RL=4.7KΩ 28 s Figure 3: Quiescent Current vs.supply oltage Preregulator To improve the transient immunity a preregulator stabilized the internal supply voltage to.this internal voltage is present at Pin3(z).This voltage should not be used as an output because the output capability is very small( 10μ A). This output may be used as an option when a better transient behaviour for supply voltages less than 8 is required(see also application note). In this case a capacitor(100nf - 1μF) must be connected between Pin3 and.if this feature is not used Pin3 must be left open. Reset Circuit The block circuit diagram of the reset circuit is shown in Fig.4. the reset circuit supervises the output voltage. The reset thereshold of 4. is defined with the internal reference voltage and standby output drivider. The reset pulse delay time trd,is defined with the charge time of an external capacitor : 2 TRD= 2μA The reaction time of the reset circuit originates from the discharge time limitation of the reset capacitor and is proportional of the reset capacitor and is proportional to the value of. The reactioin time of the reset circuit increases the noise immunity.standby output voltagedrops below the reset threshold only a bit longer than th reaction time results in a shorter reset delay time. The nominal reset delay time will be generated for standby output voltage drops longer than approximately 0μs. The typical reset output waveforms are shown in Fig.. Sense Comparator The sense comparator compares an input signal with an internal voltage reference of typical.the use of an external voltage divider makes this comparator flexible in th application. It can be used to supervise the input voltage either before or after the protection diode and to give additional informations to the microprocessor like low voltage warnings. UTC UNINIC TECHNOLOGIES CO. LTD 6

7 2 REF OUT 22K - - REG 2.8 Figure 4 40 IN.0 RT0.1 RT 1 1. tr t trd trr trd SWITCH ON INPUT DROP DUMP Figure OUTPUT OERLOAD SWITCH OFF UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. UTC UNINIC TECHNOLOGIES CO. LTD 7