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| TECHNICAL DATA 5-V Low-Drop Fixed Voltage Regulator ILE4268 Features * Output voltage tolerance < 2 % * Very low current consumption * Low-drop voltage * Watchdog * Settable reset threshold * Overtemperature protection * Reverse polarity protection * Short-circuit proof * Suitable for use in automotive electronics * Wide temperature range Functional Description This device is a 5-V low-drop fixed-voltage regulator. The maximum input voltage is 45 V. It can deliver an output current of at least 180 mA. The IC is short-circuit proof and features temperature protection that disables the circuit in the event of impermissibly high temperatures. The watchdog function is disabled as a function of the load, so that a controller is not interrupted during sleep mode by a watchdog reset. Application Description The IC regulates an input voltage V, in the range 5.5 V < V, < 45 V to Vqrated = 5-O V. In the event of an output voltage VQ < VRT, a reset signal is generated. The wiring of the reset switching threshold input enables the value of VRT to be reduced. The reset delay time can be adjusted using an external capacitor. The integrated watchdog monitors the connected active controller. If there is no positive-going edge at the watchdog input, the reset output is set to low. The reset delay capacitor provides a wide adjustment range for the pulse repetition time. The watchdog function is only activated if the load exceeds 8 mA. This ensures that a microcontroller is not activated during power-down and the current drain is not increased. The IC is protected against overload and overtemperature. 1 ILE4268 Pin Configuration (top view) Pin Definitions and Functions Pin 1, 2, 8, 13, 19, 20 3 4 ... 7, 14 ... 17 9 10 Symbol Function N. C. Not connected. QRES GND DRES SRES Reset output; the open collector output is connected to the 5-V output via an integrated resistor of 30 k. Ground Reset delay; connect a capacitor to ground for delay time adjustment. Reset switching threshold; for setting the switching threshold, output to ground with voltage divider. If this input is connected to ground, the reset is triggered at an output voltage of 4.5 V. Watchdog input; positive-edge-triggered input for monitoring a microcontroller. 5-V output voltage; block to ground with 22-F capacitor, ESR < 3 . Input voltage; block to ground directly on the IC with ceramic 11 12 18 W VQ VI 2 ILE4268 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 the series transistor via a buffer. Saturation control as a function of the load current prevents any over-saturation of the power element. If The externally scaled down output voltage at the reset threshold input drops below 1.35 V, the external reset delay capacitor is discharged by the reset generator. If the voltage on the capacitor reaches the lower threshold VST, a reset signal is generated on the reset output and not cancelled again until the upper threshold voltage is exceeded. If the reset threshold input is connected to GND, reset is triggered at an output voltage of 4.5 V. A connected microcontroller is monitored by the watchdog logic. If pulses are missing, the rest output is set to low. The pulse sequence time can be set within a wide range with the reset delay capacitor. The IC also incorporates a member of internal circuits for protection against: * Overload * Overtemperature * Reverse polarity Block Diagram 3 ILE4268 Absolute Maximum Ratings Tj=-40 to 150C Parameter Input Input voltage Input current Reset Output Voltage Current Reset Delay Voltage Current Watchdog Watchdog input Reset Input Reset threshold Output Output voltage Output current Ground Current Symbol Limit Values min. max. -30 45 Unit Notes Vi Ii VR IR VD ID Vw VRE VQ IQ IM V Internally limited -0.3 7 V Internally limited -0.3 7 V Internally limited -0.3 -0.3 -0.3 7 7 7 V V V - Internally limited -100 50 150 150 mA C C -- Temperatures Junction temperature Ti Storage temperature Ts -50 4 ILE4268 Operating Range Parameter Input voltage Junction temperature Thermal Resistance Junction ambient (soldered) Junction case Symbol Vi Tj RthjA RthjC Limit Values Unit min. max. 45 V -40 150 C 70 25 K/W K/W Notes Optimum reliability and life time are guaranteed if the junction temperature does not exceed 125 C in operating mode. Operation at up to the maximum junction temperature of 150C is possible in principle. Note, however, that operation at the maximum permitted ratings could affect the reliability of the device. Characteristics Vi = 13.5 V;- 40 C Tj 125 C (unless otherwise specified) Parameter Output voltage Output current limiting Current consumption Iq = Ii - IQ Current consumption Iq = Ii - IQ Drop voltage Load regulation Supply voltage regulation Reset Generator Switching threshold Switching voltage Saturation voltage Saturation voltage Charging current Delay switching threshold Delay time Delay time Pull-up Lower switching threshold 1) Drop Symbol VQ IQ Iq Iq VDR VQ VQ min. 4.90 180 -- -- -- Limit Values typ. max. 5.00 5.10 250 300 13 0.25 10 10 -- 450 20 0.5 30 30 Unit V mA HA mA V mV mV Test Condition 5mA IQ 150mA; 6V V i 28V; -- IQ = 0 mA IQ = 150 mA IQ= 150mA1) IQ= 5 to 150mA Vi = 6 to 28 V IQ= 150mA VRT VRE VR Vc Id VDU td tt RR VDRL 4.2 1.28 5 1.4 10 18 0.2 4.5 1.35 0.2 30 12 1.8 15 2 30 0.4 4.8 1.45 0.5 100 18 2.2 25 46 0.55 V V V mV A V ms ms k V 1 mA extern VQ < VRT Vc = 1.0V -- Cd = 100 nF Cd = 100 nF with resp. to VQ -- voltage = VI - VQ (measured when the output voltage has dropped 100 mV from the nominal value obtained at 13.5 V input) 5 ILE4268 Characteristics (cont'd) Parameter Watchdog Discharge current Charging current Switching voltage Lower switching threshold Watchdog periode Watchdog trigger time Activating current Slew rate ICd Id VCd VDWL TWP FWT IQ Vw 1.5 5 1.6 0.2 30 25 2 5 3.5 12 1.8 0.4 55 40 8 -- 5.2 18 2.0 0.55 75 60 15 -- A A V V ms ms mA Vc = 1.0V Vc = 1.0V -- Q = 100nF Cd = 100nF Symbol Limit Values min. typ. max. Unit Test Condition Activates watchdog V/s from 20 % up to 80 % VQ Note: The reset output is low in range from VQ= 1 V to VRT. Test Circuit 6 ILE4268 Timing (Watchdog Disabled) Timing of the Watchdog Function 7 ILE4268 Package Dimensions P-DSO-20-6 8 |
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