LM9070M

LM9070 Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control December 1999 LM9070 Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control General Description The LM9070 is a 5V, 3% accurate, 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 LM9070 contains a variety of protection features such as reverse battery, over-voltage shutdown, thermal shutdown, input transient protection and a wide operating temperature range. A unique two-input logic control scheme is used to enable or disable the regulator output. An ON/OFF input can be provided by an ignition switch derived signal while a second, Keep-Alive input, is generated by a system controller. This allows for a system to remain ON after ignition has been switched OFF. The system controller can then execute a power-down routine and after which command the regulator OFF to a low quiescent current state (60 µA max). 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). Features n n n 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 Keep-alive feature with 2 logic control inputs 60V Load dump transient protection Thermal shutdown Short circuit protection and disable safety features Reverse battery protection Low OFF quiescent current, 50 µA maximum Wide operating temperature range −40˚C to +125˚C TO-263 and 20-pin power surface mount packages Lead form compatible with TLE4267 TO-220 regulator (package TA07D) Connection Diagrams and Ordering Information 7-Lead TO-263 Surface Mount Package (Top View) 20-Pin SO Package DS012831-1 Backside metal is internally connected to ground. DS012831-2 Order Number LM9070S See NS Package Number TS7B Order Number LM9070M See NS Package Number M20B © 1999 National Semiconductor Corporation DS012831 www.national.com LM9070 Connection Diagrams and Ordering Information (Top View) (Continued) 7-Lead TO-220 Package (Odd numbered pins bent forward away from package body) DS012831-3 Tab is internally connected to ground. Order Number LM9070T See NS Package Number TA07B 7-Lead TO-220 Package (Even numbered pins bent forward away from package body) DS012831-4 Tab is internally connected to ground. Order Number LM9070T/Flow LB09 See NS Package Number TA07D www.national.com 2 LM9070 Absolute Maximum Ratings (Note 1) Input Voltage ON/OFF, Keep-Alive Inputs (through 1 kΩ) 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 −50˚C to +150˚C Operating Ratings (Note 1) −26V to +26V 60V −50V 5 mA Internally Limited 150˚C 12 kV, 2 kV 260˚C Input Voltage Ambient Temperature θjc, TO-220, TO-263 Packages θja, TO-220, TO-263 Packages θj-pins, SO20 Package θja, SO20 Package 6V to 26V −40˚C to +125˚C 3˚C/W 43˚C/W 25˚C/W 85˚C/W 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 REGULATOR OUTPUT VOUT ∆VOUT Line ∆VOUT Load Iq Output Voltage Line Regulation Load Regulation Quiescent Current 5 mA ≤ IOUT ≤ 250 mA IOUT = 5 mA, 9V ≤ VIN ≤ 16.5V IOUT = 5 mA, 6V ≤ VIN ≤ 26V VIN = 14.4V, 5 mA ≤ IOUT ≤ 250 mA VON/OFF ≤ VIN IOUT = 5 mA IOUT = 250 mA, VIN ≥ 8V IOUT = 5 mA, VIN = 5V IOUT = 250 mA, VIN = 6V VIN ≤ 16.5V, Regulator OFF −40˚C ≤ TJ ≤ 60˚C 60˚C ≤ TJ ≤ 135˚C IOUT = 5 mA IOUT = 250 mA RL = 1Ω fripple = 120 Hz, Vripple = 1 Vrms IOUT = 50 mA In Keep-Alive mode VON/OFF = 0V, VKA = 0V VIN Peak ≤ 60V, RL = 100Ω, τ = 100 ms ∆VOUT Required to Generate a Reset Output 4.85V ≤ VOUT ≤ 5.15V Isink = 1.6 mA, VOUT > 3.2V 1.4V ≤ VOUT ≤ 3.2V Vhigh tdelay Idelay Rpu VKAlow Reset Output High Voltage Delay Time Charging Current for Cdelay Internal Pull-up Resistance Low Input Threshold Voltage, Keep-Alive Input Cdelay = 0.1 µFd 0.9 VOUT 7 10 12 20 60 300 800 0.4 60 4 27 7 4.5 1.5 µA µA mV mV A dB V V V 4.85 5.15 25 50 50 4 25 10 50 V mV mV mV mA mA mA mA Parameter Conditions Min Max Units Ioff OFF Quiescent Current Vdo Isc RR VothOFF OVthr Vo Transient RESET OUTPUT Vth Dropout Voltage Short Circuit Current Ripple Rejection Safety VOUT Latch-OFF Threshold Overvoltage Shutdown Threshold VOUT during Transients Threshold Voltage −300 −500 0.4 0.8 VOUT 31 30 80 mV V V V ms µA kΩ Vlow Reset Output Low Voltage CONTROL LOGIC 3.5V ≤ VOUT ≤ 5.25V 0.3 VOUT 0.5 VOUT V 3 www.national.com LM9070 Electrical Characteristics Symbol CONTROL LOGIC VKAhigh VON/OFF low VON/OFF high ION/OFF Parameter (Continued) 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. Conditions Min Max Units High Input Threshold Voltage, Keep-Alive Input Low Input Voltage, ON/OFF Input High Input Voltage, ON/OFF Input Input Current, ON/OFF Input 3.5V ≤ VOUT ≤ 5.25V Rseries = 1 kΩ Rseries = 1 kΩ VON/OFF ≤ 4V 4V < VON/OFF < 7V VON/OFF ≥ 7V 0.6 VOUT −2 4 0.8 VOUT 2 26 330 670 10 V V V µA µA mA kΩ kΩ RpuKA RpdON/OFF Internal Pull-up Resistance, Keep-Alive Input Internal Pull-down Resistance ON/OFF Input 0V ≤ VIN ≤ 26V 0V ≤ VON/OFF ≤ 26V 20 50 100 210 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, input pins VIN and the ON/OFF input will withstand ten pulses of ± 12 kV from a 150 pF capacitor discharged through a 560Ω resistor with each pin bypassed with a 22 nF, 100V capacitor. Reset Operation and Protection Features DS012831-5 www.national.com 4 LM9070 Typical Performance Characteristics Turn ON Characteristics (TA = 25˚C unless indicated otherwise) Normalized Output Voltage vs Temperature Turn OFF Characteristics DS012831-6 DS012831-7 DS012831-8 Output Voltage at Input Voltage Extremes Quiescent Current vs Input Voltage Input Current vs Input Voltage Regulator Switched OFF DS012831-9 DS012831-10 DS012831-11 Dropout Voltage vs Temperature Reset Delay Time vs Temperature Short Circuit Current vs Temperature DS012831-12 DS012831-13 DS012831-14 5 www.national.com LM9070 Typical Performance Characteristics Output Capacitor ESR (TA = 25˚C unless indicated otherwise) (Continued) Maximum Power Dissipation (TO-263 and SO-20 Packages) Maximum Power Dissipation (TO-220 Package) DS012831-15 DS012831-16 DS012831-17 ON/OFF, Keep-Alive and Safety Latch-Off Control Diagrams Note: If Keep-Alive is provided by a microprocessor powered by the output voltage of the LM9070, the logic “1” voltage level will track VOUT as the regulator turns OFF. Simple ON/OFF control (Keep-Alive input must be high to turn OFF output) Keep-Alive Mode; Turn ON with ON/OFF control, Keep output biased with Keep-Alive input, Turn OFF with Keep-Alive (Keep-Alive low keeps output ON, Keep-Alive going high turns output OFF) DS012831-18 DS012831-19 Switch ON with ON/OFF input; Keep output biased with Keep-Alive; Hold ouput ON with ON/OFF; Turn OFF with ON/OFF input. (Temporary Keep-Alive Mode) Safety Latch OFF of VOUT when in Keep-Alive Mode (ON/OFF going high required to turn Output back ON) DS012831-21 DS012831-20 www.national.com 6 LM9070 Control Logic Truth Table ON/OFF Input L ↑ Keep-Alive Input X X X H L L X L Output Voltage 0V 5V 5V 0V 5V 5V ∆VOUT ≥ −300 mV VOUT ≤ 4V Reset Output L ↑ after delay Operating Condition Low quiescent current standby (OFF) condition Output turns ON Normal ON condition Output turns OFF Output kept ON by Keep-Alive Input Output remains ON (or turns ON) Output pulled out of regulation, reset flag generated Output latches OFF H ↓ ↓ ↑ H L H H L L H L Block Diagram DS012831-22 Application Information The LM9070 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 LM9070 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). This regulator is suitable for applications where continuous connection to the battery is required (Refer to the Typical Application Circuit ). ON/OFF control of the regulator and system can be accomplished by switching the ON/OFF input to the battery or ignition supply VIN supply through a SPST 7 switch. If this input becomes open circuited, an internal pull-down resistor ensures that the regulator turns OFF. When the regulator is switched OFF the current load on the battery drops to less than 60 µA. With the possibility in many applications for VIN and the ON/OFF input pins to be connected in a system through long lengths of wire, the ESD protection of these pins has been increased to 12 kV with the addition of small input bypass capacitors. DS012831-23 FIGURE 1. Typical Application Circuit www.national.com LM9070 Application Information (Continued) 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 recovery 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 typical delay time interval can be estimated using the following equation: 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. With the Keep-Alive input, a system microprocessor has the ability to keep the regulator ON (with a logic “0” on Keep-Alive) after the ON/OFF input has been commanded OFF. A power-down sequence, when system variables are typically stored in programmable memory, can be executed and take as much time as necessary. At the end of the operation the micro then pulls Keep-Alive high and the regulator and system turn OFF and revert to the low quiescent current standby mode. For additional system reliability, consideration has been made for the possibility of a short circuited load at the output of the regulator. When the regulator is switched ON, conventional current limiting and thermal shutdown protect the regulator. When the regulator is switched OFF however, a grounded VCC supply to the micro (due to the shorted regulator output) will force the Keep-Alive input to be low and thus try to maintain the Keep-Alive mode of operation. With a shorted load, the drain on the battery could be as high as 1.5A. A separate internal circuit monitors the output voltage of the regulator. If VOUT is less than 4V, as would be the case with a shorted load, the Keep-Alive function is logically disabled to ensure that the regulator turns OFF and reverts to only a 50 µA load on the battery. DS012831-24 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 LM9070 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 significant 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, the input voltage moves through the dropout region of operation (VIN of 3V to 5.5V) too quickly for an oscillation to be established. MICROPROCESSOR SYSTEM REGULATOR WITH KEEP-ALIVE INTERVAL AT TURN-OFF The following circuit illustrates a system application utilizing both of the logic control inputs of the LM9070. Closing the ON/OFF switch powers ON the system. Once powered, the system controller sets the Keep-Alive line low. The NPN transistor is used only to signal the controller that the ON/ OFF switch has been opened and the system is to be turned OFF. Upon detecting this high level at the ON/OFF Sense input line, the controller can then perform a power down routine. The system will remain fully powered until the controller commands total shut down by taking the Keep-Alive line high. The system then shuts OFF and reverts to a very low current drain standby condition until switched back on. FIGURE 2. Control Logic Not Used Conventional load dump protection is built in to withstand up to +60V and −50V transients. A 1 kΩ resistor in series with the ON/OFF and Keep-Alive inputs are recommended to provide the same level of transient protection for these pins if required. Protection against reverse polarity battery connections is also built in. With a reversed battery the output of the LM9070 will not go more negative than one diode drop below ground. This will prevent damage to any of the 5V load circuits. For applications where the control logic is not required the logic pins should be configured as shown in Figure 2. A separate device, called the LM9071, can be used. The LM9071 is available in a 5-lead TO-220 package and does not provide control logic functions, but still retains all of the protection features of the LM9070. www.national.com 8 LM9070 Application Information (Continued) DS012831-25 9 www.national.com LM9070 Physical Dimensions inches (millimeters) unless otherwise noted 20-Lead (0.300" Wide) Molded Small Outline Package, JEDEC Order Number LM9070M NS Package Number M20B www.national.com 10 LM9070 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 7-Lead Molded TO-220 Order Number LM9070T NS Package Number TA07B 11 www.national.com LM9070 Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 7-Lead Molded TO-220 Order Number LM9070T/Flow LB09 NS Package Number TA07D 7-Lead Molded TO-263 Order Number LM9070S NS Package Number TS7B www.national.com 12 LM9070 Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control Notes 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. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: support@nsc.com www.national.com National Semiconductor Europe Fax: +49 (0) 1 80-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 1 80-530 85 85 English Tel: +49 (0) 1 80-532 78 32 Français Tel: +49 (0) 1 80-532 93 58 Italiano Tel: +49 (0) 1 80-534 16 80 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: sea.support@nsc.com National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.