LM9071 Low-Dropout System Voltage Regulator with Delayed Reset General Description Features The LM9071 is a 5V, 250 mA low-dropout voltage regulator. The regulator features an active low delayed reset output flag which can be used to reset a microprocessor system on turn-ON and in the event that the regulator output falls out of regulation for any reason. An external capacitor programs a delay time interval before the reset output can return high. Designed for automotive application the LM9071 contains a variety of protection features such as reverse battery, over-voltage shutdown, thermal shutdown, input transient protection and a wide operating temperature range. Design techniques have been employed to allow the regulator to remain operational and not generate false reset signals when subjected to high levels of RF energy (300V/m from 2 MHz to 400 MHz). n n n n n n n n n n n Automotive application reliability 3% output voltage tolerance Insensitive to radiated RFI Dropout voltage less than 800 mV with 250 mA output current Externally programmed reset delay interval Thermal shutdown Short circuit protection Reverse battery protection Wide operating temperature range −40˚C to +125˚C TO-220 and TO-263 power surface mount power packages Pin for pin compatible with the LM2927, L4947 and TLE4260 Typical Application and Connection Diagrams (Top View) 5-Lead TO-220 Package DS012832-3 Order Number LM9071T/Flow LB03 See NS Package Number T05D 5-Lead TO-263 Surface Mount Package DS012832-1 DS012832-4 5-Lead TO-220 Package Tab and Backside metal on all packages internally connected to ground. Order Number LM9071S See NS Package Number TS5B DS012832-2 Order Number LM9071T See NS Package Number T05A © 1999 National Semiconductor Corporation DS012832 www.national.com LM9071 Low-Dropout System Voltage Regulator with Delayed Reset December 1999 LM9071 Absolute Maximum Ratings (Note 1) DC Input Voltage Positive Input Transient (t < 100 ms) Negative Input Transient (t < 1 ms) Reset Output Sink Current Power Dissipation Junction Temperature ESD Susceptibility (Note 2) Lead Temperature (Soldering, 10 seconds) Storage Temperature −26V to +26V 60V −50V 5 mA Internally Limited 150˚C 12 kV, 2 kV −50˚C to +150˚C Operating Ratings (Note 1) Input Voltage Ambient Temperature θjc, TO-220, TO-263 Packages θja, TO-220, TO-263 Packages 6V to 26V −40˚C to +125˚C 3˚C/W 43˚C/W 260˚C Electrical Characteristics The following specifications apply for VCC = 6V to 26V, −40˚C ≤ TA≤+125˚C, unless otherwise specified. COUT = 47 µFd with an ESR < 3Ω. CIN = 1 µFd. Symbol Parameter Conditions Min Max Units 4.85 5.15 V 25 mV REGULATOR OUTPUT VOUT Output Voltage ∆VOUT Line Line Regulation ∆VOUT Load Load Regulation Iq Quiescent Current Vdo Dropout Voltage 5 mA ≤ IOUT ≤ 250 mA IOUT = 5 mA, 9V ≤ VIN ≤ 16.5V IOUT = 250 mA 50 mV VIN = 14.4V, 5 mA ≤ IOUT ≤ 250 mA IOUT = 5 mA 60 mV 4 mA IOUT = 250 mA, VIN ≥ 8V IOUT = 5 mA, VIN = 5V 25 mA IOUT = 250 mA, VIN = 6V IOUT = 5 mA IOUT = 250 mA RL = 1Ω Fripple = 120 Hz, Vripple = 1 Vrms IOUT = 50 mA Isc Short Circuit Current RR Ripple Rejection OVthr Overvoltage Shutdown Threshold VO Transient VOUT during Transients VIN Peak ≤ 60V, RL = 100Ω, τ = 100 ms Threshold Voltage ∆VOUT Required to Generate a Reset Output 4.8V ≤ VOUT ≤ 5.2V Isink = 1.6 mA, VOUT > 3.2V 0.35 10 mA 50 mA 300 mV 800 mV 1.5 A 60 dB 27 V 7 V −500 mV 0.4 V RESET OUTPUT Vth Vlow Reset Output Low Voltage −300 1.4V ≤ VOUT ≤ 3.2V 0.8 0.8 VOUT V Vhigh Reset Output High Voltage tdelay Delay Time 7.6 35 Idelay Charging Current for Cdelay 10 30 µA Rpu Internal Pull-up Resistance 12 80 kΩ Cdelay = 100 mFd V ms Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and conditions, see the Electrical Characteristics. Note 2: All pins will survive an ESD impulse of ± 2000V using the human body model of 100 pF discharged through a 1.5 kΩ resistor. In addition the input voltage pin will withstand ten pulses of ± 12 kV from a 150 pF capacitor discharged through a 560Ω resistor when bypassed with a 22 nF, 100V capacitor. www.national.com 2 (TA = 25˚C unless indicated otherwise) Turn OFF Characteristics Turn ON Characteristics DS012832-5 Normalized Output Voltage vs Temperature DS012832-6 DS012832-7 Output Voltage at Input Voltage Extremes Quiescent Current vs Input Voltage DS012832-8 Dropout Voltage vs Temperature Short Circuit Current vs Temperature DS012832-9 Reset Delay Time vs Temperature DS012832-10 Output Capacitor ESR DS012832-13 DS012832-11 DS012832-12 3 www.national.com LM9071 Typical Performance Characteristics LM9071 Typical Performance Characteristics (TA = 25˚C unless indicated otherwise) (Continued) Maximum Power Dissipation (TO-220 Package) Maximum Power Dissipation (TO-263 Package) DS012832-14 DS012832-15 Reset Operation and Protection Features DS012832-16 Block Diagram DS012832-17 www.national.com 4 covery from a fault condition the delay capacitor is used to hold the micro in a reset condition for a programmable time interval to allow the system operating voltages and clock to stabilize before executing code. The delay time interval can be estimated by the following equation: The LM9071 voltage regulator has been optimized for use in microprocessor based automotive systems. Several unique design features have been incorporated to address many FMEA (Failure Mode Effects Analysis) concerns for fail-safe system performance. FAULT TOLERANT FEATURES While not specifically guaranteed due to production testing limitations, the LM9071 has been tested and shown to continue to provide a regulated output and, not generate an erroneous system reset signal while subjected to high levels of RF electric field energy (up to 300 V/m signal strength over a 2 MHz to 400 MHz frequency range). This is very important in vehicle safety related applications where the system must continue to operate normally. To maintain this immunity to RFI the output bypass capacitor is important (47 µF is recommended). An output bypass capacitor of at least 10 µF is required for stability (47 µF is recommended). The ESR of this capacitor should be less than 3Ω. An input capacitor of 1 µF or larger is recommended to improve line transient and noise performance. Conventional load dump protection is built in to withstand up to +60V and −50V transients. Protection against reverse polarity battery connections is also built in. With a reversed battery connection the output of the LM9071 will not go more negative than one diode drop below ground. This will prevent damage to any of the 5V load circuits. INPUT STABILITY Low dropout voltage regulators which utilize a PNP power transistor usually exhibit a large increase in current when in dropout (VIN < 5.5V). This increase is caused by the saturation characteristics (β reduction) of the PNP transistor. To significantly minimize this increase in current the LM9071 detects when the PNP enters saturation and reduces the operating current. This reduction in input current can create a stability problem in applications with higher load current ( > 100 mA) where the input voltage is applied through a long length of wire, which in effect adds a significant amount of inductance in series with the input. The drop in input current may create a positive input voltage transient which may take the PNP out of saturation. If the input voltage is held constant at the threshold where the PNP is going in and out of saturation, an oscillation may be created. This is only observed where a large series inductance is present in the input supply line and when the rise and fall time of the input supply is very slow. If the application and removal of the input voltage changes at a rate greater than 500 mV/µs it will move through the dropout region of the regulator (VIN of 3V to 5.5V) too quickly for an oscillation to be established. RESET FLAG Excessive loading of the output to the point where the output voltage drops by 300 mV to 500 mV will signal a reset flag to the micro. This will warn of a VCC supply that may produce unpredictable operation of the system. On power-up and re- 5 www.national.com LM9071 Application Hints LM9071 Physical Dimensions inches (millimeters) unless otherwise noted 5-Lead Molded TO-220 Order Number LM9071T NS Package Number T05A 5-Lead Molded TO-220 Order Number LM9071T/Flow LB03 NS Package Number T05D www.national.com 6 LM9071 Low-Dropout System Voltage Regulator with Delayed Reset Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 5-Lead Molded TO-263 Order Number LM9071S NS Package Number TS5B LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. 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