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| UTC L2949E LINEAR INTEGRATED CIRCUIT MULTIFUNCTION VERY LOW DROP VOLTAGE REGULATOR DESCRIPTION The UTC L2949E is a monolithic integrated 5V 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. DIP-8 SOP-8 FEATURES *Operating dc supply voltage range 5V to 28V. *Transient supply voltage up to 40V. *Extremely low quiescent current in standby mode. *High precision standby output voltage 5V1% *Output current capability up to 100mA. *Very low dropout voltage less than 0.5V. *Reset circuit sensing the output voltage *Programmable reset pulse delay with external capacitor *Voltage sense comparator. *Thermal shutdown and short circuit protections. SOP-20 PIN CONNECTIONS Vz CT N.C. VS SI Vz CT 1 2 3 4 8 7 6 5 VOUT SO RES GND GND GND GND GND N.C. DIP-8/SOP-8 N.C. RES 1 2 3 4 5 6 7 8 9 10 SOP-20 20 19 18 17 16 15 14 13 12 11 SI VS N.C. GND GND GND GND N.C. VOUT SO UTC UNISONIC TECHNOLOGIES CO. LTD 1 QW-R102-014,A UTC L2949E BLOCK DIAGRAM LINEAR INTEGRATED CIRCUIT Vz VOUT CT VS PREREGULATOR 5V 2 + RES 2V REG SI REF 1.23V SENSE 1.23V GND RESET VS SO ABSOLUTE MAXIMUM RATINGS PARAMETER DC Operating Supply Voltage Transient Supply Voltage(T<1s) Output Current Output Voltage Output Voltage Reset Output Sense Output Output Current Reset Output Sense Output Preregulator Output Voltage Preregulator Output Current Junction Temperature Storage Temperature Range SYMBOL VCC VCC TR Io Vo VRES Vso IRES Iso Vz Iz Tj Tstg RATING 28 40 Internally Limited 20 20 20 5 5 7 5 -40+150 -55+150 UNIT V V V V mA V mA UTC UNISONIC TECHNOLOGIES CO. LTD 2 QW-R102-014,A UTC L2949E THERMAL DATA DESCRIPTION LINEAR INTEGRATED CIRCUIT SYMBOL Rth j-amb Rth j-pins TJSD RATING 100 200 50 15 165 unless otherwise specified) UNIT /W /W Thermal Resistance Junction-ambient DIP-8 SOP-8 SOP-20 Thermal Resistance Junction-pin (SOP-20) Thermal Shutdown Junction temperature ELECTRICAL CHARACTERISTICS(Vs=14V;-40 Output Voltage Output Voltage Output Voltage Dropout voltage SYMBOL Vo Vo Vo VD CONDITIONS Tj=25;Io=1mA 6V 4.95 4.90 4.75 TYP. 5 5 MAX 5.05 5.10 5.25 0.25 0.4 0.5 0.4 UNIT V V V V V V V 0.1 0.2 0.3 Input to Output Voltage Difference in Undervoltage Condition Max Output Leakage Line Regulation Load Regulation Current Limit VIO Iouth ** VOL VOLO ILIM VIN=25V,Vo=5.5V 6V 50 80 20 30 400 400 300 5 A mV mV mA mA A mV 105 120 200 100 Quiescent Current IQSE 200 Quiescent Current IQ Io=100mA ** With this test we guarantee that with no output current the output voltage will not exceed 5.5V RESET PARAMETER Reset Thereshold Voltage Reset Thereshold Hysteresis Reset Pulse Delay Reset Output Low Voltage Reset Output Gigh Leakage Current Delay Comparator Thereshold Delay Comparator Thereshold Hysteresis SYMBOL VRT VRTH tRD VRL IRH VCTth VCTth,hy CONDITIONS MIN 50 55 TYP. Vo-0.5V 100 100 MAX 200 180 0.4 1 UNIT V mV ms V A V mV CT=100nF;TR100s RRES=10K to Vs1.5V VRES=5V 2 100 UTC UNISONIC TECHNOLOGIES CO. LTD 3 QW-R102-014,A UTC L2949E SENSE PARAMETER Sense Low Thereshold Sense Thereshold Hysteresis Sense Output Low Voltage Sense Output Leakage Sense Input Current LINEAR INTEGRATED CIRCUIT SYMBOL Vst Vsth VSL ISH ISI CONDITIONS MIN 1.16 20 TYP. 1.23 100 MAX 1.35 200 0.4 1 -3 UNIT V mV V A A VSI1.16V;Vs3V Rso=10K to Vo Vso=5V;VSI1.5V VSI=0 -20 -8 PREREGULATOR PARAMETER Preregulator Output Voltage Preregulator Output Current Note 1:Foldback characteristic SYMBOL Vz Iz CONDITIONS Iz=10A MIN 4.5 TYP. 5 MAX 6 10 UNIT V A APPLICATION CIRCUIT VOUT Vz (optional) VBAT VS CT PREREGULATOR 5V 2 + RES VOUT 2V REG SI 1.23V RESET VS SO REF SENSE 1.23V GND For stability:Cs1F, Co 4.7F, ESR<10at 10KHz Recommended for application:Cs=Co=10F to 100F APPLICATION INFORMATION Suppl Voltage Transient High supply voltage transients can cause a reset output signal disturbation. For supply voltage greater than 8V the circuit shows a high immunity of the reset output against supply transients of the reset output against supply transients of more than100V/s. For supply voltages less than 8V supply transients of more than 0.4V/s can cause a reset signal disturbation. To improve the transient behaviour for supply voltages less than 8V a capacitor at pin 3 can be used. A capacitor at pin 3(C31F ) reduces also the output noise. UTC UNISONIC TECHNOLOGIES CO. LTD 4 QW-R102-014,A UTC L2949E LINEAR INTEGRATED CIRCUIT FUNCTIONAL 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. Voltage Regulator The voltage regulator uses an lsolated Collector Vertical PNP transistor as a regulating element. 10 5 0 20 100 IOUT(mA) Figure 1: Foldback Characteristic of Vo 200 With this structure very low dropout voltage at currents up to 100mA is obtained.The dropout operation of the standby regulator is maintained down to 3V input supply voltage.The output voltage is regulated up to the transient input supply voltage of 4V.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 300A. 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 UNISONIC TECHNOLOGIES CO. LTD 5 QW-R102-014,A UTC L2949E LINEAR INTEGRATED CIRCUIT 2.0 IQ mA VOUT 1.5 1.0 0.5 RL=4.7K 0 RL=100 VOUT 5V 0V 2V 5V Vs 40V Figure 2: Output Voltage vs.Input voltage 28V Vs Figure 3: Quiescent Current vs.Supply Voltage 5V Preregulator To improve the transient immunity a preregulator stabilized the internal supply voltage to 5V.This internal voltage is present at Pin3(Vz).This voltage should not be used as an output because the output capability is very small(10 A). This output may be used as an option when a better transient behaviour for supply voltages less than 8V is required(see also application note). In this case a capacitor(100nF - 1F) must be connected between Pin3 and GND.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 4.5V 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 CT: CT 2V TRD= 2A The reaction time of the reset circuit originates from the discharge time limitation of the reset capacitor CT and is proportional of the reset capacitor CT and is proportional to the value of CT. 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 50s. The typical reset output waveforms are shown in Fig.5. Sense Comparator The sense comparator compares an input signal with an internal voltage reference of typical 1.23V.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 UNISONIC TECHNOLOGIES CO. LTD 6 QW-R102-014,A UTC L2949E LINEAR INTEGRATED CIRCUIT 2V REF 1.23V 22K CT RESET + OUT REG + 2.8V Figure 4 VOUT VIN 5.0V VRT+0.1V VRT VOUT1 40V 1.5V tR RESET tRD SWITCH ON tRR tRD DUMP OUTPUT OVERLOAD SWITCH OFF t INPUT DROP Figure 5 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 UNISONIC TECHNOLOGIES CO. LTD 7 QW-R102-014,A |
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