TECHNICAL DATA 5-V Low-Drop Fixed Voltage Regulator ILE4278 Features • Output voltage tolerance ≤ ± 2%, 4% • Very low current consumption • Separated reset and watchdog output • Low-drop voltage • Watchdog • Adjustable watchdog activating threshold • Adjustable reset threshold • Overtemperature protection • Reverse polarity protection • Short-circuit proof • Suitable for use in automotive electronics • Wide temperature range PDSO-14 ORDERING INFORMATION ILE4278D Functional Description The ILE 4278 is a monolithic integrated low-drop fixed-voltage regulator which can supply loads up to 200 mA. The device is available in the 14-SOP-225 package. It is designed to supply microprocessor systems under the severe conditions of automotive applications and therefore equipped with additional protection functions against over load, short circuit and over temperature. Of course the ILE 4278 can also be used in other applications where a stabilized voltage is required. An input voltage VI in the range of 6V ≤ VI ≤ 28V is regulated to VQ,nom = 5 V with an accuracy of ± 2%. An input voltage VI in the range of 28V ≤ VI ≤ 45 V is regulated to VQ,nom = 5 V with an accuracy of ± 4%. The device operates in the wide temperature range of Tj = – 40 to 12 5 ℃. Two additional features are implemented in the ILE 4278 a load dependent watchdog function as well as a sophisticated reset function including power on reset, under voltage reset, adjustable reset delay time and adjustable reset switching threshold. The watchdog function monitors the microcontroller, including time base failures. In case of a missing rising edge within a certain pulse repetition time the watchdog output is set to LOW. Programming of the max. repetition time can be done easily by an external reset delay capacitor. To prevent a reset in case of missing pulses, the watchdog output WO is separate from the reset output RO for the ILE 4278. November, 2012, Rev. 01 ILE4278 The watchdog output can be used as an interrupt signal for the microcontroller. In any case it is possible to connect pin WO and pin RO externally. When the controller is set to sleep mode or low power mode its current consumption drops and no watchdog pulses are created. In order to avoid unnecessary wake up signals due to missing pulses at pin WI the watchdog feature can be disabled as a function of the load current. The switch off threshold is set by an external resistor to pin WADJ. The watchdog function can also be used as a timer, which periodically wakes up the controller. Therefore the pin WADJ has to be connected to the output Q. The power on reset feature is necessary for a defined start of the microprocessor when switching on the application. The reset signal at pin RO goes high after a certain delay timed trd when the output voltage of the regulator has surpassed the reset threshold. The delay time is set by the external delay capacitor. An under voltage reset circuit supervises the output voltage. In case VQ falls below the reset threshold the reset output is set to LOW after a short reset reaction time trr. The reset LOW signal is generated down to an output voltage VQ of 1 V. In addition the reset switching threshold can be adjusted by an external voltage divider. This feature is useful with microprocessors which guarantee a safe operation down to voltages below the internally set reset threshold of 4.65 V typical. November, 2012, Rev. 01 ILE4278 Pin Configuration (top view) PDSO-14 Figure 1 Pin Definitions and Functions Pin Symbol Function 1 WO 2 WADJ 3, 4, 5, 10, 11, 12 GND 6 D Reset Delay; connect a capacitor to ground for delay time adjustment. 7 RADJ Reset Switching Threshold Adjust; for setting the switching threshold, connect a voltage divider from output to ground. If this input is connected to ground, the reset is triggered at the internal threshold. 8 WI Watchdog Input; rising edge-triggered input for monitoring a microcontroller. 9 Q 5 V Output Voltage; block to ground with min. 10uF capacitor, ESR ≤ 5Ω 13 I Input Voltage; block to ground directly on the IC with ceramic capacitor. 14 RO Watchdog Output; the open collector output is connected to the 5 V output via an integrated resistor of 30 ㏀. Watchdog Adjust; an external resistor to GND determines the watchdog activating threshold. Ground Reset Output; the open collector output is connected to the 5 V output via an integrated resistor of 30 ㏀. November, 2012, Rev. 01 ILE4278 Block Diagram November, 2012, Rev. 01 ILE4278 Absolute Maximum Ratings Tj = – 40 to 150 ℃ November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 Test Circuit VDR = VI -VO Outside the control range Figure 3 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 November, 2012, Rev. 01 ILE4278 PDSO-14 November, 2012, Rev. 01