Preliminary TECHNICAL DATA 5-V Low-Drop Fixed Voltage Regulator ILE 4278 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 P-DSO-14-8 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 overtemperature. 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 accuracy of 2%. 6V VI 28V is regulated to VQ,nom = 5 V with an An input voltage V I 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 C. 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 Rev. 00 1 ILE 4278 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. 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. Rev. 00 2 ILE 4278 Pin Configuration (top view) 14-SOP WO WADJ GND GND GND D RADJ 1 2 3 4 5 6 7 14 13 12 11 10 9 8 RO VΙ GND GND GND VQ WΙ Figure 1 Pin Definitions and Functions Pin Symbol Function 1 WO Watchdog Output; the open collector output is connected to the 5 V output via an integrated resistor of 30 kτ. 2 WADJ Watchdog Adjust; an external resistor to GND determines the watchdog activating threshold. GND 3, 4, 5, 10, 11, 12 Ground 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. 10 ←F capacitor, ESR 5 τ. 13 I Input Voltage; block to ground directly on the IC with ceramic capacitor. 14 RO Reset Output; the open collector output is connected to the 5 V output via an integrated resistor of 30 kτ. Rev. 00 3 ILE 4278 Block Diagram VΙ 9 13 Temperature Sensor Protection Circuit 14 VQ RO Reset Generator + - Control Amplifier 7 1 Bandgap Reference 6 Watchdog 2 3-5, 10-12 WADJ GND RADJ WO D 8 WΙ Figure 2 Rev. 00 4 ILE 4278 Absolute Maximum Ratings Tj = – 40 to 150 C Parameter Symbol Limit Values Unit Notes min. max. VI II – 42 45 V – – – mA Internally limited VQ IQ –1 25 V – – – mA Internally limited VRO IRO – 0.3 25 V – –5 5 mA – VD ID – 0.3 7 V – –2 2 mA – Input Voltage I Voltage Current Output Voltage Q Voltage Current Reset Output RO Voltage Current Reset Delay D Voltage Current Reset Switching Threshold Adjust RADJ Voltage Current VRADJ IRADJ – 0.3 7 V – – – mA Internally limited VWI IWI – 0.3 7 V – – – mA Internally limited VWO IWO – 0.3 25 V – –5 5 mA – Watchdog Input WI Voltage Current Watchdog Output WO Voltage Current Rev. 00 5 ILE 4278 Absolute Maximum Ratings (cont’d) Tj = – 40 to 150 C Parameter Symbol Limit Values Unit Notes min. max. VWADJ IWADJ – 0.3 7 V – – – mA Internally limited IGND – 100 50 mA – Junction temperature Tj – 40 150 – Storage temperature Tstg – 50 C C Watchdog Adjust WADJ Voltage Current Ground GND Current Temperatures 150 – Note: ESD protection according to MIL Std. 883: 2 kV. Maximum ratings are absolute ratings; exceeding any one of these values may cause irreversible damage to the integrated circuit. Operating Range Parameter Input voltage Junction temperature Symbol Limit Values Unit Notes min. max. VI Tj 6.0 45 V – – 40 125 C – Rthj-a Rthj-pin – 80 K/W 1) – 30 K/W Measured to pin 4 Thermal Resistance Junction ambient Junction pin 1) Package mounted on PCB 80 ⌠ 80 ⌠ 1.5 mm3; 35←Cu ; 5← Sn; Heat Sink Area 6 cm2; zero airflow. Note: In the operating range the functions given in the circuit description are fulfilled. Rev. 00 6 ILE 4278 Electrical Characteristics VI = 13.5 V; – 40 C Tj 125 C (unless otherwise specified) Parameter Symbol Limit Values min. typ. max. Unit Test Condition Output voltage VQ 4.90 5.00 5.10 V 1mA IQ 150 mA; 6 V VI 28 V Output voltage VQ 4.8 5.0 5.2 V 1 mA IQ 50 mA; 28 V VI 45 V Output current limiting IQ Iq,o 200 400 – mA – 180 200 ←A VQ = 4.8 V Tj = 25 C; IQ = 0 mA Current consumption Iq = I I – I Q Iq,o – 210 230 ←A Current consumption Iq = I I – I Q Iq,150 – 5 12 mA IQ = 0 mA; Tj = 85 C IQ = 150 mA Drop voltage; VDR = VI – VQ Vdr – 0.25 0.5 V IQ = 150 mA1) Load regulation αVQ.lo – 30 – 5 – mV Line regulation αVQ,li – 5 20 mV IQ = 5 to 150 mA; VI = 6 V VI = 6 to 28 V IQ = 5 mA Reset threshold VQ,rt 4.5 4.65 4.8 V RADJ connected to GND Reset headroom αVQ,rt = 180 350 – (VQ,nom – VQ,rt) VRADJ,th 1.28 1.35 1.45 VRO,l – 0.20 0.40 mV IQ = 10 mA V V VQ ∫=3.5 V Rext = 10 kτ=to VQ VQ ∫=1 V Current consumption Iq = I I – I Q Reset Generator Reset adjust threshold Reset low voltage Reset high voltage Reset pull-up Charging current VRO,h RRO ID,c 4.5 – – V – 20 30 46 kτ Internal connected to VQ 2 5 8 ←A VD = 1.0 V Rev. 00 7 ILE 4278 Electrical Characteristics (cont’d) VI = 13.5 V; – 40 C Tj 125 C (unless otherwise specified) Parameter Upper timing threshold Lower reset timing threshold Delay time Reset reaction time Symbol Limit Values Unit Test Condition min. typ. max. VDU VDRL 1.5 1.9 2.3 V – 0.2 0.3 0.4 V – trd trr 12 20 28 ms 0.4 1.0 2.0 ←s CD = 47 nF CD = 47 nF VWADJ,th IQ/IWADJ dVWI/dt VWOL VWOH RWO 1.28 1.35 1.45 V Voltage at WADJ 650 720 800 – IQ 10 mA 5 – – V/←s From 20% up to 80% VQ – 0.2 0.4 V Rext > 10 kτ to VQ 4.5 – – V – 20 30 46 kτ Internally connected to VQ VD = 1.0 V VD = 1.0 V Watchdog Activating threshold Current ratio Slew rate Watchdog low voltage Watchdog high voltage Watchdog pull-up ID,wc Discharge current ID,wd Upper timing threshold VDU Lower watchdog timing VDWL Charge current 2 5 8 0.6 1.3 2.0 ←A ←A 1.5 1.9 2.3 V – 0.5 0.7 0.9 V – threshold Watchdog output pulse period TWD,p 42 60 80 ms Cd = 47 nF Watchdog output low time tWD,l 7 13 19 ms VQ > VRT Watchdog trigger time TWI,tr 35 47 61 ms Cd = 47 nF 1) Measured when the output voltage VQ has dropped 100 mV from the nominal value. Rev. 00 8 ILE 4278 Test Circiut ΙΙ C Ι1 1000 µF Ι WO VΙ WO VΙ WΙ VWADJ 9 VQ ΙQ C Ι2 470 nF Ι WADJ WADJ VWO 13 VW VD CQ 10 µF ILE 4278 1 2 8 3-5, 10-12 GND 6 D CD 47 nF Ι GND RO 14 7 RADJ Ι RO VQ VRO VRE VDR = VΙ -VO Outside the control range Figure 3 Rev. 00 9 ILE 4278 Application Information Input, Output The input capacitors CI1 and CI2 are necessary for compensating line influences. Using a resistor of approx. 1 τ in series with CI1, the LC circuit of input inductance and input capacitance can be damped. To stabilize the regulation circuit the output capacitor CQ is necessary. Stability is guaranteed at values CQ ∫ 10 ←F with an ESR 5 τ within the operating temperature range. Application Circuit VΙ +12 V C Ι1 CΙ2 13 9 VQ 470 nF 1 ILE 4278 14 8 3-5, 10-12 GND 6 D WO R1 CQ 22 µF RO WΙ RADJ 7 2 WADJ µP *) Cooling Area CD 47 nF R WADJ R2 *) or short to GND for internal threshold Figure 4 Rev. 00 10 ILE 4278 Reset Timing The power-on reset delay time is defined by the charging time of an external capacitor CD which can be calculated as follows: CD = (αtrd ⌠ ID,c)/αV CD = delay capacitor αtrd = delay time ID,c = charge current, typical 5 ←A αV = VDU, typical 1.9 V VDU = upper delay switching threshold at CD for reset delay time The reset reaction time trr is the time it takes the voltage regulator to set the reset out LOW after the output voltage has dropped below the reset threshold. It is typically 1 ←s for delay capacitor of 47 nF. For other values for CD the reaction time can be estimated Definitions: using the following equation: trr 20 s/F ⌠ CD Reset Timing (Watchdog Disabled) VΙ t < t rr VQ V Q, rt d V Ι D,c = dt CD VD t V DU V DRL t rd t rr t VRO t Power-on-Reset Thermal Shutdown Voltage Dip at Input Undervoltage Secondary Spike Overload at Output Figure 5 Rev. 00 11 ILE 4278 Reset Switching Threshold The present default value is 4.65 V. When using the ILE 4278 the reset threshold can be set to 3.5 V < VQ,rt < 4.6 V by connecting an external voltage divider to pin RADJ. The calculation can be easily done since the reset adjust input current can be neglected. If this feature is not needed, the pin has to be connected to GND. VQ,rt = Vref(1 + R1/R2) Definitions: VQ,rt = Reset threshold Vref = comparator reference voltage, typical 1.35 V (Reset adjust input current 50 nA) ILE 4278 Ι 13 9 Q 30 kΩ 14 Band-GapReference RO Band-GapReference 1.35 V 1.35 V >1 + - R1 7 3 ... 5, RADJ 10 ... 12 GND R2 Figure 6 The reset output pin is internally connected to the 5 V output Q via a 30 kτ pull-up resistor. Down to an output voltage VQ of typical 1 V the reset LOW signal at pin RO is generated. For the timing of the reset feature please refer to the data sheet, Figure 5. Rev. 00 12 ILE 4278 Watchdog Activating The calculation of the external resistor which adjusts the watchdog switch off threshold can be done by the following equation. RWADJ = VWADJ,th ⌠ (IQ/IWADJ)/IQ,act Definitions: VWADJ,th = switch off threshold, typical 1.35 V IQ/IWADJ = current ratio, typical 720 IQ,act = switch off load current ILE 4278 Ι Q Band-GapReference HIGH + - WADJ Watchdog active LOW Watchdog disabled R WADJ GND Figure 7 Rev. 00 13 ILE 4278 Watchdog Timing The frequency of the watchdog pulses has to be higher than the minimum pulse sequence which is set by the external reset delay capacitor CD. Calculation can be done according to the formulas given in Figure 8. The watchdog output is internally connected to the output Q via a 30 kτ pull-up resistor. To generate a watchdog created reset signal for the microcontroller the pin WO can be connected to the reset input of the microcontroller. It is also allowed to parallel the watchdog out to the reset out. Timing of the Watchdog Function VW Ι t VΙ VQ t T WD, p VD t T WI, tr VDU VDWL VWO T WI, tr = t WD, L (VDU - VDWL ) Ι D, wd C D ; T WD, p = (VDU -VDWL ) (Ι D, wc + Ι D, wd ) Ι D, wc x Ι D, wd C D ; t WD, L = t (VDU - VDWL ) Ι D, wc t CD Figure 8 Rev. 00 14 ILE 4278 Hints for Unused Pins Symbol Function Connect to RO Reset output open D Reset delay open or to output Q RADJ Reset switching threshold adjust GND WI Watchdog input GND WO Watchdog output open WADJ Watchdog adjust 1) 2) to output Q via a 270 kτ resistor: Watchdog always active to GND: Watchdog disabled Rev. 00 15 ILE 4278 Drop Voltage Vdr versus Output Current IQ Current Consumption Iq versus Output Current IQ mV 700 16 I q mA 14 600 12 500 10 400 8 V dr VI = 13.5 V T j = 25 ˚C Tj = 125 C 300 6 Tj = 25 C 200 4 100 2 0 0 50 100 150 200 250 0 mA 0 50 100 150 200 mA 300 ΙQ Current Consumption Iq versus Input Voltage VI IQ Output Voltage VQ versus Input Voltage VI 12 mA Iq mA VQ Tj = 25 ˚C 10 10 8 8 6 6 R L= 33 Ω R L= 33 Ω 4 4 R L= 50 Ω 2 0 2 R L= 100 Ω 0 10 20 30 40 V 50 VI 0 0 2 4 6 8 V VΙ Rev. 00 16 ILE 4278 Charge Current ID,wc and Discharge Current ID,wd versus Temperature Tj Ι 8 µA VD VΙ = 13.5 V VD = 1.0 V 7 Switching Voltage VDU, VDWL and VDRL versus Temperature Tj 3.2 V 2.8 V Ι = 13.5 V 2.4 6 Ι D, wc 5 2.0 4 1.6 3 1.2 2 Ι D, wd 1 0 -40 0 40 80 120 V DU 0.8 V DWL 0.4 V DRL 0 -40 C 0 40 80 Tj Tj Output Voltage VQ versus Temperature Tj Output Current Limit IQ versus Input Voltage VI 500 5.2 VQ 120 ˚C 160 IQ V 5.1 Tj = 25 ˚C mA 400 VΙ = 13.5 V 5.0 300 4.9 200 4.8 100 4.7 4.6 -40 0 0 40 80 120 ˚C 160 Tj 0 10 20 30 40 V 50 VI Rev. 00 17 ILE 4278 Package Outlines P-DSO-14-8 Rev. 00 18