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| TECHNICAL DATA 5-V LOW-DROP FIXED VOLTAGE REGULATOR Functional Description The device is a 5-V low-drop fixed-voltage regulator. The maximum input voltage is 42 V (65 V, 400 ms). Up to an input voltage of 26 V and for an output current up to 550 mA it regulates the output voltage within a 2% accuracy. The short circuit protection limits the output current of more than 650 mA. The IC can be switched off via the inhibit input. An integrated watchdog monitors the connected controller. The device incorporates overvoltage protection and temperature protection that disables the circuit at unpermissibly high temperatures. Features * Output voltage tolerance 2% * Low-drop voltage * Integrated overtemperature protection * Reverse polarity protection * Input voltage up to 42 V * Overvoltage protection up to 65 V ( 400 ms) * Short-circuit proof * Suitable for use in automotive electronics * Wide temperature range * Adjustable reset and watchdog time ILE4271-2 Pin Definitions and Functions Pin 1 2 3 4 5 6 7 Symbol I INH RO GND D W Q Function Input; block to ground directly on the IC with ceramic capacitor. Inhibit Reset Output; the open collector output is connected to the 5 V output via an integrated resistor of 30 kOhm Ground Reset Delay; connect a capacitor to ground for delay time adjustment. Watchdog Input 5-V Output; block to ground with 22 uF capacitor, ESR < 3 Ohm. 1 ILE4271-2 Application Description The IC regulates an input voltage in the range of 5.5 V < VI < 36 V to VQnom = 5.0 V. Up to 26 V it produces a regulated output current of more than 550 mA. Above 26 V the saveoperating-area protection allows operation up to 36 V with a regulated output current of more than 300 mA. Overvoltage protection limits operation at 42 V. The overvoltage protection hysteresis restores operation if the input voltage has dropped below 36 V. The IC can be switched off via the inhibit input, which causes the quiescent current to drop below 50 uA. A reset signal is generated for an output voltage of VQ < 4.5 V. The watchdog circuit monitors a connected controller. If there is no positive-going edge at the watchdog input within a fixed time, the reset output is set to low. The delay for power-on reset and the maximum permitted watchdog-pulse period can be set externally with a capacitor. Design Notes for External Components An input capacitor CI is necessary for compensation of line influences. The resonant circuit consisting of lead inductance and input capacitance can be damped by a resistor of approx. 1 Ohm in series with CI. An output capacitor CQ is necessary for the stability of the regulating circuit. Stability is guaranteed at values of CQ 22 uF and an ESR of <3 Ohm. Circuit Description The control amplifier compares a reference voltage, which is kept highly accurate by resistance adjustment, to a voltage that is proportional to the output voltage and drives the base of a series transistor via a buffer. Saturation control as a function of the load current prevents any over-saturation of the power element. If the output voltage decreases below 4.5 V, an external capacitor CD on pin 4 (D) will be discharged by the reset generator. If the voltage on this capacitor VD drops below VDRL, a reset signal is generated on pin 2 (RO), i.e. reset output is set low. If the output voltage rises above 4.5 V, CD will be charged with constant current. After the power-on-reset time VD reaches VDU and the reset output will be set high again. The value of the poweron-reset time can be set within a wide range depending on the capacity of CD. The value of the pull-up resistor at reset output is typically 30 kOhm. After VD has reached the voltage VDU and reset was set to high, the watchdog circuit is enabled and discharges CD with a constant current. If there is no positive-going edge observed at watchdog input, CD will be discharged down to VDWL. Then reset will be set low and the watchdog circuit will be disabled. CD will be charged with the current as at power-on reset until VD reaches VDU and reset will be set high again. If a watchdog pulse will be observed before CD is discharged down to VDWL, the watchdog circuit will be enabled and CD will be charged too, but reset will not be set low. After VD has reached VDU, the periodical behavior starts again. The IC also incorporates a number of internal circuits for protection against: * * * * Overload Overvoltage Overtemperature Reverse polarity 2 ILE4271-2 Block Diagram 3 ILE4271-2 Maximum & Absolute Maximum Ratings Maximum Ratings Parameter Symbol Junction temperature, J Storage temperature, S Input voltage, VI Inhibit voltage, UINH Input current, II Output voltage, UQ Output current, IQ Current on common pin ,IGND Reset voltage, UR Reset current, IR Output voltage, UQ Output current, IQ Output voltage, UQ Output current, IQ Thermal resistance junction ambient (P-TO-263-7-1), Rth ja, Thermal resistance junction case (P-TO-263-7-1), Rth jc Unit o C o C V V A V mA mA V A V mA V mA o C /W /W min. -40 6 4,9 -5 4,9 -5 - max. 125 36 internally limited 5,1 internally limited 5,1 internally limited 70** 3** Absolute Maximum Ratings min. max. -40 150 -50 150 -42 42 65* internally limited -1 16 -5 internally limited -0.5 - -1 16 -5 internally limited -0.3 7 -5 5 -0.3 7 -5 5 70** 3** * Time of influence t 400ms ** Thermal resistance junction ambient for IC with heat dissipater is calculated by formula: Rth ja = Rth jc + Rth ca (1) Rth jc - thermal resistance junction case, oC /W. Application circuit and heat dissipater have to provide TJ 125 . Maximum power Ptot,, dissipated by IC for TA , is calculated by formula: Ptot = (125 - TA) / Rth ja (2) 125 - maximum permitable operating junction temperature, . 4 ILE4271-2 Optimum reliability and life time are guaranteed if the junction temperature does not exceed 125 oC in operating mode. Operation at up to the maximum junction temperature of 150 oC is possible in principle. Note, however, that operation at the maximum permitted ratings could affect the reliability of the device. Operating Range Parameter Input voltage Junction temperature Thermal Resistance Junction ambient Junction case Symbol VI Tj Rthja Rthjc Limit Values min. max. 6 40 - 40 150 - - 65 70 3 Unit o Notes - - - P-TO263 - V C K/W K/W K/W Zthjc - 2 K/W t <1 ms Characteristics VI = 13.5 V; - 40 oC Tj 125 oC (unless otherwise specified) Parameter, unit Output voltage, V Symbol VQ Test Condition 6VVI 26V; 5mAIQ550mA 26VVI 36V; IQ300mA VQ=0 Ve=0; IQ=0mA Limit Values Min. Max. 4.90 5.10 4.90 650 5.10 50 Note Output current limiting, mA Current consumption, , Iq = II Current consumption, mA Iq = II - IQ Drop voltage, V Load regulation, mV Supply voltage regulation, mV IQmax Iq VDr VQ(I) UQ(U) IQ=5mA IQ=550mA IQ=550mA; VI=5V IQ=550mA 5 IQ 550mA VI = 6 V 6B UI 26V IQ=5mA 1,5 75 90 0.7 50 25 3 5 ILE4271-2 Parameter, unit Inhibit Inhibit ON voltage, V Inhibit OFF voltage, V Inhibit current, uA Overvoltage protection , Watchdog Upper timing threshold, V Lower watchdog timing threshold, V Discharge current, uA Charge current, uA Watchdog period, ms Watchdog trigger time, ms Reset Generator Switching threshold, V Reset high voltage, V Reset low voltage, V Resistance of circuit, kOhm Lower reset timing threshold, V Upper reset timing threshold, V Delay time, ms Charge current, uA Notes Symbol VINH,on VINH,off IINH VI, OV VDU VDWL Idis Id tw twt VRT VROH VROL R VDRL VDU td Id Test Condition UQ >4.5V UQ <0.8V UINH=5V Limit Values Min. Max. 3,5 0,8 8 40 1.4 0.2 25 46 2.3 0.8 3.5 25 75 66 4.8 400 46 0.8 2.3 18 25 Note UD=1V UD=1V CD=100 nF CD=100 nF 1.5 8 40 30 4.5 4.5 18 0.2 1.4 IR=3mA, VQ=4.4V Direct connection to pin Q VQ < VRT CD = 100 nF VD = 1.0 V 8 8 1 Following capacitances are connected: on input C1I = 1000 uF(electrolytic), C2I = 470 nF on output CQ = 22 uF (electrolytic). 2 Measurements of parameters have to carry out with pulse equipment. 3 Drop voltage VDr= VI - VQ (measured when the output voltage has dropped 100 mV from the nominal value obtained at 13.5 V input) 1) 6 ILE4271-2 Test Circuit Application Circuit 7 ILE4271-2 Time Response Time Response, Watchdog Behavior 8 ILE4271-2 Package Dimensions P-TO 220-7-180 9 |
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