LM9073S

LM9073 Dual High Current Low-Dropout System Regulator PRELIMINARY April 2000 LM9073 Dual High Current Low-Dropout System Regulator General Description The LM9073 is a high performance voltage regulator system with operational and protection features that address many requirements of automotive applications. Two regulated outputs are provided. The main regulator provides a precision 2% tolerance 5V output at 700mA with a low dropout characteristic. The second output, an External Supply regulator, provides a 5V output with 2% tolerance for load currents up to 100mA. This External Supply output is fully protected from short circuit to ground or the unregulated input supply (ignition or battery potentials in automotive applications) which makes it suitable for powering remotely located load circuits or sub-systems. The LM9073 also contains a programmable delayed system reset output. Two control inputs are provided. An ON/OFF input intended for connection to an ignition switch, and a Keep Alive input whereby a system can remain powered after ignition has been switched OFF. Additionally, a watchdog function is built in to enhance system operationally reliability. For EMC concerns the LM9073 remains fully operational and does not generate false rest signals while subjected to greater than 100mA, 1MHz to 400MHz bulk current injection signals on the input supply and External Supply output lines. Features n n n n n n n n n n n n n n Two 5V regulated outputs: 700mA, 2% Main output 100mA, 2% External Supply output External Supply output protected from shorts to battery Good EMI (1MHz to 400MHz, BCI) immunity Separate ON/OFF and Keep-Alive control inputs Less than 100µA quiescent current in OFF state Programmable delayed reset output Adjustable threshold voltage for generating reset Built-in system watchdog timer Input transient protection over 60V to −45V Less than 1V dropout at full load Wide −40˚C to 125˚C operating temperature range Surface mount, TO−263 and standard TO−220 power packages Applications n Automotive module supply power conditioning n Remote sub−system powering n Continuous operation for save routines and E2PROM programing after power down command n Safety relates systems − EMC operational with a system watchdog monitor Connection Diagram 11 Lead TO−263 Package 11 Lead TO−220 Package DS101296-2 DS101296-1 Top View Order Number LM9073S See NS Package Number TS11B Top View Order Number LM9073T See NS Package Number TA11B © 2000 National Semiconductor Corporation DS101296 www.national.com LM9073 Block Diagram DS101296-3 www.national.com 2 LM9073 Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Input Voltage Input Voltage (transient, t≤400mS) Forced Output Voltages Main Output External Supply Output ON/OFF Input Voltage(Note 6) ON/OFF Input Current Keep Alive In, Reset Out, CDELAY, Reset Adjust,Watchdog Trigger −45V to 45V 60V −0.3V to 7V −0.3V to 27V −0.3V to 16V ± 20mA In, C Watchdog Junction Temperature Storage Temperature ESD Susceptibility(Note 2) Lead temperature (Soldering, 10 Sec) −0.3V to 7V 150˚C −65˚C to 150˚C 2000V 265˚C Operating Ratings(Note 1) Input Voltage Range Ambient Temperature Range Thermal Resistance θJC θJA 6V to 27V −40˚C to 125˚C 4˚C/W 43˚C/W Electrical Characteristics The following specifications apply for 6V ≤ vIN ≤ 19V, tCASE = 25˚C unless otherwise specified. COUT ≥ 6µF with 0.3Ω ≤ ESR ≤ 0.3Ω on each regulator output. Symbol MAIN REGULATOR 10mA ≤ ILOAD ≤ 700mA VMAIN Output Voltage 19V ≤ VIN ≤ VSD, 5mA ≤ ILOAD ≤ 700mA VIN = 16V, 10mA ≤ ILOAD ≤ 700mA ILOAD = 700mA, 8V ≤ VIN ≤ 16V VIN > 5.5V, 10mA ≤ ILOAD ≤ 700mA(Note 5) 30 RL = 1Ω VIN = 9V, 50Hz ≤ freq ≤ 20kHZ, VRIPPLE = 4V P−P 3mA ≤ ILOAD ≤ 100mA 19V ≤ VIN ≤ VSD 3mA ≤ ILOAD ≤ 100mA RELOAD RELINE VEDO VSD IESC VESC PSRR Input Current IQOFF IQ Quiescent Input Current with Both Regulators OFF. No Load Quiescent Current 8V ≤ VIN ≤ 16V 16V ≤ VIN ≤ 42V 8V ≤ VIN ≤ 19V, IL = 0mA 100 10 15 µA mA mA Load Regulation Line Regulation Dropout voltage, VIN − VEXT Overvoltage Shutdown Threshold Output Short Circuit Current Output Short Circuit Ripple Rejection RL = 1Ω No effect on other functions VIN = 9V, 50Hz ≤ freq ≤ 20kHZ, VRIPPLE = 4VPP −0.3 40 VIN = 16V, 3mA ≤ ILOAD ≤ 100mA ILOAD = 100mA, 8V ≤ VIN ≤ 16V VIN > 5.5V, 3mA ≤ ILOAD ≤ 100mA (Note 5) 30 40 4.9 4.8 5.1 5.2 25 25 1 36 2000 V V mV mV V V mA dB Parameter Conditions LM9073 Min Max Units RMLOAD RMLINE VMDO VSD IMSC PSRR Load Regulation Line Regulation Dropout Voltage, VIN− VMAIN Overvoltage Shutdown Threshold Output Short Circuit Current Ripple Rejection External Supply Regulator VEXT Output Voltage 4.9 4.8 5.1 5.2 25 25 0.8 36 250 27 V V mV mV V V mA V dB 3 www.national.com LM9073 Electrical Characteristics (Continued) The following specifications apply for 6V ≤ vIN ≤ 19V, tCASE = 25˚C unless otherwise specified. COUT ≥ 6µF with 0.3Ω ≤ ESR ≤ 0.3Ω on each regulator output. Symbol Input Current Additional Input Current with both Regulators ON VIN ≥ 8V, ILTOTAL = IMAIN + ILEXT ILTOTAL = 700mA + 100mA = 800mA 0V < VIN < 8V, (Note 4) ILTOTAL = IMAIN + ILEXT ILTOTAL = 700mA + 100mA = 800mA VMAIN output controls Reset Reset Adjust (pin 11 )open circuited Reset Adjust (pin 11) shorted to ground VTHRH VLOW VHIGH RP−U TDELAY TRISE TFALL Watchdog VTRIGL VTRIGR TWD TPW RTRIG Trigger Input Logic Low Voltage Trigger Input Logic High Level CWATCHDOG = 0.1µF (low leakage) IWATCHDOG for charging the watchdog 2 .08 V V High Switching Threshold Logic Low Output Threshold VMAIN output controls Reset 1V ≤ VMAIN ≤ VTHRL RRESET = 50kΩ to VMAIN Normal opeation, VTHRL≤ VMAIN ≤ THRH,, I =0 CDELAY = 0.1µF From 10% VMAIN to 90% VMAIN CLRESET = 50pF From 90% VMAIN to 10% VMAIN CLRESET = 50pF SOURCE Parameter Conditions LM9073 Min Max Units INON 1.2 X ILTOTAL X ILTOTAL LINDO Reset Output Additional Input Current when in Dropout 1.5 4.0 4.2 V VTHRL Low Switching Threshold 4.5 5.35 4.7 5.75 0.4 V V V Logic High Output Threshold Internal Pull-Up Resistance Reset Delay Interval Output Rise Time Output Fall Time VMAIN −50mV 2.4 35 VMAIN 6.0 70 1.5 0.5 V kΩ mS µS µS Watchdog Refresh Window 35 70 mS Watchdog Trigger Pulse Width Trigger Input Pull-down Resistance ON Threshold for ON/OFF Input OFF Threshold for ON/OFF Inpu ON/OFF Input Current Turn ON Threshold for Keep Alive Input Turn OFF Threshold for Keep Alive Input Pull−Down Resistance at Keep Alive Input (Note 3) 0V ≤ VK−A ≤ 5V Rseries = 22kΩ Rseries = 22kΩ (Note 3) 1.4V ≤ VON/OFF ≤ 4.5V −0.3V ≤ VON/OFF ≤ 7V(Note 6) 10 5 40 µS kΩ Control Inputs VON VOFF ION/OFF 3.5 1.5 1 −1 2 0.8 5 40 4.5 2.5 12 5 V V µA mA V V kΩ ONK−A OFFK−A RP−D www.national.com 4 LM9073 Electrical Characteristics (Continued) Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. “Operating Ratings” indicate conditions for which the device is functional, but do not guarantee specific performance limits. “Electrical Characteristics” state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance. Note 2: Human body model, 150 pFcapacitor discharged through a 1.5 kΩ resistor. Note 3: If either control input is left open circuited the regulators will turn OFF. Note 4: The input quiescent current will increase when the regulators are in dropout conditions. The amount of additional input current is a direct function of the to a load current on both outputs. The peak increase in current is limited to 50% of the total load current. Note 5: The dropout voltage specifications actually indicate the saturation voltage of the PNP power transistors used in each regulator. Over the full load current and temperature ranges the Main regulator will output at least 4.5V and the External Supply regulator at lease 4.7V with an input voltage of only 5.5V Note 6: The ON/OFF input is internally clamped to a 7V zener diode through a 1KΩ resistor. Quiescent Input Current vs. Input Voltage Turn-On Characteristic DS101296-4 DS101296-5 Turn-Off Characteristic Normalized Output Voltages vs Temperature DS101296-6 DS101296-7 5 www.national.com LM9073 Electrical Characteristics (Continued) Main Output Dropout Voltage vs Load Current Output Voltages at Input Voltage Extremes DS101296-8 DS101296-9 External Supply Output Short Circuit Current Output Short Circuit Current vs Temperature DS101296-10 DS101296-11 Watchdog and Reset Delay Time vs Temperature Maximum Power Dissipation DS101296-12 DS101296-13 www.national.com 6 LM9073 Electrical Characteristics Output Capacitor ESR (Continued) DS101296-14 7 www.national.com LM9073 Electrical Characteristics (Continued) DS101296-15 www.national.com Operational Characteristics 8 LM9073 Control Logic Truth Table ON/OFF Input Keep-Alive Input Main Output Voltage External Supply Output Voltage L Rising Edge H L L X 0V 5V 5V 0V 5V 5V Reset Output 0V Rising after delay 5V Operating Condition OFF, Input curent < 100µA Outputs turn ON, Power ON delayed reset Normal ON condition Main output pulled out of regulation, Reset flag generated. Threshold depends on Reset Adjust seting (pin 11) Keep-Alive, Continued normal operation Outputs turned ON by Keep-Alive Input H X < 4V or < 4.5V or < 5.35V 5V 5V X 0V Falling Edge L H Rising Edge 5V 5V 5V Rising after delay Application Information Pin Description and Functionality The LM9073 is a precision dual voltage regulator optimized for use in powertrain module applications but will also find use in a wide variety of automotive and industrial applications were precision supply regulation is required in harsh operating environments. The following will describe the functionality of each of the package pins. Figure 1. Circuit Block Diagram DS101296-16 Input Voltage (pin 4) The LM9073 has been designed to connect directly to the ignition or battery supply in automotive applications. For this type of supply the regulator been designed to withstand up to +60V and −45V supply transients such as load dump. An overvoltage shut down protection circuit turns OFF both of the regulator outputs should supply transients exceed typically +33V to fully protect all load circuitry. This higher threshold allows normal operation with 24VDC applied to the input as in the event when two batteries are used to start a vehicle. Protection of the system is also provided for inadvertent reverse polarity battery connections. 9 The current drain on the supply line is directly proportional to the load currents on the two voltage regulators. With no load current on either output the regulator requires 15mA maximum quiescent current for biasing internal circuitry. During dropout conditions (VIN < 5.5V) the additional input current can rise to 50% of the total load current. With less than 3V applied to the input, internal biasing circuitry shuts OFF. When switched OFF the regulator can remain connected to the battery supply with a current drain of less than 100µA. Main Output (pin 10) The Main Output regulator provides a well controlled (2% tolerance maximum) 5V supply line with a total load current www.national.com LM9073 Application Information (Continued) External Supply Output (pin 5) The External Supply Output regulator is a secondary 5V, 2% tolerance regulated output of the LM9073. this 100mA output is available to bias sensors and other devices located external to the main system module. For providing remote power the External Supply Output is fully protected against short circuit connections to the battery or input supply (up to 27V) and to ground. These shorted fault conditions do not effect the operation of the main supply nor generate a reset of the system. Like the main output a bypass capacitor is required for stability. This capacitor should be also greater than 6µF with an ESR between 0.3Ω and 3Ω. ranging up to 700mA. This relatively high level of output current is sufficient to provide power to a large number of load circuits in a variety of module applications. This output has a short to ground current limit between 900mA and 2A. It is not protected for shorts to battery however, but can withstand an output short to a potential of 7 Volts or less. To maintain stability of this supply line an output bypass capacitor is required. This capacitor must be at least 6µF with an equivalent series resistance (ESR) between 0.3Ω and 3Ω over temperature. The Main Output is sensed for the generation of the system reset output. Figure 2. Reset Generator and Watchdog Circuitry DS101296-17 Reset Output (pin 7) The Reset Output is an active low logic signal provided to reset a system mircocontroller on power up and in the event that the Main Output falls out of regulation. This output is guaranteed to provide a logic low level ( < 0.4V) whenever the Main Output supply is below a threshold set by the Reset Adjust pin strap option (see Reset Adjust section) or is pulled above 5.75V. This general reset prevents erratic system operation which may occur with out-of-specification supply potentials. The Reset Output has an active pull down which can sink up to 15mA of current and a passive pull-up (through a 4KΩ resistor) to the Main Output to ensure voltage compatibility with the system supply. Capacitive loading on this reset line will directly affect the rise time of the reset signal. The Reset Output will maintain a logic low level with a Main Output voltage of only 1V. Below 1V the active pull-down device switches OFF (sink current of only 500µA). At such a low supply potential, system controllers are generally inoperative. The Reset Output has a built-in delay time interval which is programmable by the section of the delay capacitor. Reset Adjust (pin 11) The low Vmain threshold voltage for generating a system reset can be shifted by 500mV through the use of a pin strap to ground on pin 11. With this pin shorted to ground the threshold is between 4.5V and 4.7V. With this pin left open the threshold is shifted to between 4.0V and 4.2V. This lower threshold allows the system to remain operational longer during power down. The higher threshold ensures that the system is reset when the nominal 5V supply is low by 10%, which in some cases can produce uncertain microprocessor operation. Delay Capacitor (pin 8) www.national.com 10 LM9073 Application Information (Continued) The Delay Capacitor (CDELAY) controls a time interval during which the Reset Output remains low after the Main Output has established normal operating condition. This feature holds the system in reset for a time to allow all load circuitry to properly bias before executing functions. This interval is applied at power−up and following any event that may trigger the system reset function. Figure 2 illustrates the delayed reset generator. Two comparators continually monitor the Main Output supply. Window comparators C1 and C2 detect if the Main Supply is below 4.6V (4.1V with Reset Adjust open circuited) or exceeds 5.5V typically. If this is true (at power−on for example) the control logic turns ON the discharge transistor and holds CDELAY low (at 0.9V). Comparator C4 then outputs a logic low system Reset signal within 2µS after detecting the out of regulation condition. Figure 3. Watchdog and Reset Operation DS101296-18 The Delay Capacitor remains discharged until the window comparator senses that the Main Output is within normal operating range (C1 and C2 outputs are both low). When this condition is met, the discharge transistor is turned OFF and CDELAY is charged positively by an internal 6µA current source. The Reset Output will remain low until the delay capacitor has reached 4V, at which point it will go high and the system will begin normal operation. This delay time interval is controlled by the section of CDELAY and can be determined from the following equation: TDELAY = (0.5 x 106) x CDELAY A 0.1µF capacitor will produce a typical delay interval of 50mSec. To ensure a consistent delay time interval, the discharge transistor is always latched ON by the window comparators, and can not be switched OFF to start a new delay interval until CDELAY has been discharged to less than or equal to 0.9V. This sets a fixed starting voltage (0.9V) and ending voltage (4V) for the charging of the Delay Capacitor. Watchdog Capacitor (pin 2) The LM9073 also provides a simple system watchdog timer. The watchdog timer requires the system controller to issue a pulse at a regular interval (programmable through the selection of Cwatchdog) to provide an indication that the system is properly executing controlling software code. The absence of a pulse before the watchdog timer comes out could indicate that the system is caught in a infinite loop and the system is reset The watchdog capacitor is held discharged to ground at any time that the system is reset. When the reset is released the capacitor quickly charges to 0.9V (with a charging current of 11 approximately 50µA) then slowly charges positive with a charging current of 6µA. If this capacitor ever charges up to 4V or more, a system reset is generated. The watchdog time interval is set by the selection of Cwatchdog and can be found from the following equation: TWD = (0.5 x 106) x Cwatchdog The watchdog timer function can be disabled by grounding pin 2 or replacing Cwatchdog by a resistor with a value less than 22kΩ. With this only the reset generator can reset the system. Watchdog Trigger (pin 1) The Watchdog Trigger input accepts a pulse from the system controller to refresh the watchdog capacitor and prevent it from reaching 4V and resetting the system. This positive pulse must be at least 10µS long and triggers an internal one-shot pulse. This internal pulse latches ON Qdischarge Watchdog (figure 2) and discharges Cwatchdog to 0.9V. This latching action ensures a consistent watchdog timer interval by not allowing the capacitor to charge positively until it has been discharged to 0.9V. As shown in Figure 3, each watchdog trigger input pulse resets the timer capacitor. If the watchdog trigger signal does not refresh the timer before Cwatchdog reaches 4V, a system reset is generated. Once reset, a full reset delay interval occurs. At the end of this interval the regulator will automatically try to re-start the system by taking reset high. If the system does not respond properly by issuing a watchdog trigger signal in time, the system will once again reset. In this situation the reset output will continually cycle high (re-starting the system) for the watchdog time interval and low (re-setting the system) for the reset delay interval. www.national.com LM9073 Application Information (Continued) Keep-Alive Input (pin 9) This CMOS logic level compatible input provides a system with the ability to control it’s own ON/OFF sequencing. The Keep-Alive Input is OR’ed with the ON/OFF Input so either one can independently control the regulators. As shown in the Operational Characteristics, a system controller can take the Keep-Alive Input high at any time. If the ON/OFF switch is opened, this high level on Keep-Alive will keep the regulators ON and the entire system operational. This control is useful for providing as much time as necessary for a system to perform ’housekeeping’ chores such as programming EEPROM with system information prior to turning itself OFF (by taking the Keep-Alive Input low) and reverting to the low quiescent current state. A second use of the Keep-Alive Input can be from other modules which need information from the module powered by LM9073. A high CMOS logic level ( > 1.25V) on this input will power up the system as needed independent from the normal ON/OFF switch. A low to high transition is required during the watchdog timer interval at the trigger input. If this line is ever fixed high the timer will time-out and the system will reset. ON/OFF Input (pin 3) The ON/OFF Input enables both the Main and External Supply outputs. In a typical application this input is connected to the input supply through a series resistor (nominally 22KΩ) and a switch (Ignition, as an example).When the switch is closed this input is pulled high and switches ON both regulator outputs. This input is internally clamped to a 7V zener diode through a series 1kΩ resistor. The external series resistor together with an optional 0.1µF capacitor to ground provide filtering and current limiting to withstand transients that may appear on the input supply to maintain normal operation of the system. The switching threshold of the ON/OFF comparator has 2 Volts of hysteresis to ensure noise free control of the system. To turn the regulators ON this input must be taken above 4V. To turn the system OFF the ON/OFF Input must be open circuited or pulled below 2 Volts. Figure 4. Remote ON/OFF Control DS101296-19 System Keep-Alive Operation Figure 5 illustrates the basic concept of Keep-Alive operation. The LM9073 provides the regulated supplies to an entire microcontroller based system or module including remote sensors. The system is switched ON or OFF by a switch connected to the unregulated input supply and the ON/OFF input, pin 3. When closed the regulators turn ON and the system is held in a reset state for the duration of the delayed reset interval controlled by CDELAY. Once normal operation of the system begins, the controller needs to set an output line connected to the Keep-Alive input, pin 9, high. The system remains in normal operation until switched OFF by opening the ON/OFF switch. With Keep-Alive high the entire system remains normally biased and will remain operational until the Keep-Alive input is taken low. Transistor Q1 is shown as a means to inform the controller that the ON/OFF switch has been opened. This high level on an input line tells the controller that the system has been switched OFF. This indicates the start of the Keep-Alive interval. The system can perform whatever actions required to obtain the proper OFF state before actually powering down. These general housekeeping tasks can include putting external devices in the proper OFF condition and storing various system variables in EPROM for example. With the controller in command of the Keep-Alive interval these tasks can take whatever time necessary to complete. When completed the controller takes the Keep-Alive input to a low level and the entire system shuts down. The LM9073 powers down to a low quiescent current mode with less than 100µA drawn from the input supply. www.national.com 12 LM9073 Application Information (Continued) Figure 5. Basic Keep-Alive Operation DS101296-20 To initiate the Keep-Alive routine before actual power down, it is important for the system controller to know when the system has been switched OFF. To eliminate any interface between the controller and the ON/OFF switch and potentially noisy unregulated input supply, and simple logic scheme shown in Figure 6 can be used. With this circuitry the Reset output form the LM9073 provides the ON/OFF sensing input to the controller. When switched OFF, the main regulator output will fall out of regulation and generate a low logic level on the Reset output. This input to the controller provides the switch OFF indication and initiates the Keep-Alive interval. Control of the Keep-Alive duration is set by a logic 1 on the Keep-Alive output line from the system controller. This high level prevents the Reset output from resetting the entire system and also gates the Keep-Alive input signal to the LM9073. The inverted Reset signal provides a logic 1 to the Keep-Alive input of the LM9073. The Main output will only drop out of regulation for a very short time before the Keep-Alive input turns it back on. The Reset output remains low for the delay time interval. When it turns high the Main output switches OFF and back ON again very quickly. This continues until the system controller takes the Keep-Alive output line to a logic low level. 13 www.national.com LM9073 Application Information (Continued) Figure 6. Simple Logic Configuration to Provide ON/OFF Sensing DS101296-21 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 LM9073 detects when the PNP enters the saturation and reduces the operating current. This reduction in input current can create a stability problem in applications with higher load current ( > 200mA). where the input voltage is applied through a long length of wire which in effect add 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 500mV/mS it will move through the dropout region of the regulator (Vin of 3V to 5.5V) too quickly for an oscillation to be established. www.national.com 14 LM9073 Application Information (Continued) Figure 7. Input Bypassing DS101296-22 In the event that an oscillation is present, input bypassing can also help de-tune the resonance. Figure 7 illustrates two input bypassing approaches. The straight forward addition of a larger valued electrolitic capacitor could suffice. In this case however, if reverse battery connections are possibility it is necessary to add a series protection diode as shown to prevent damaging the polarized input capacitor. An alternative input bypassing scheme is also shown. This eliminates the use of polarized input capacitors and a series protection diode. The values shown were derived empirically in a representative typical application. Appropriate values for any given application require experimentation. Thermal Management The LM9073 is packaged in both a TO-263 surface mount power package and a narrow lead-pitch TO-220 package. To obtain operation over the highest possible load current and input voltage ranges, care must be taken to control the operating temperature of the device. Thermal shutdown protection is built with a threshold above 150˚C Conventional heat sinking techniques can be used with the TO-220 package. When applying the TO-263 package on-board heat sinking is important to prevent thermal shutdown. More copper foil area under the tab of the device will directly reduce the operating junction temperature. Use of a double sided board with vias between two planes of copper as shown in Figure 8 will improve performance ad can optimize the PC board surface area required. Figure 8. Typical TO-263 PC Board Heatsinking DS101296-23 15 www.national.com LM9073 Application Information (Continued) Figure 9. EMC Test Circuit DS101296-24 Electro-Magnetic Compatibiltiy (EMC) Systems utilizing the LM9073 will not experience loss of supply or false reset signals from the regulator when subjected to high frequency interference from a standard Bulk Current Injection test (ISO11452 Part 4 test method). The following test conditions and configuration (Figure 9) can be used to verify this performance: • • • • • • • Frequency Range Modulation 1 Modulation 2 Dwell Time Frequency Steps 1MHz to 400MHz (no modulation) 1kHz sine wave, 80% AM 1 second 1MHz (from 1MHz to 10MHz) 2MHz (from 10MHz to 200MHz) 20MHz (from 200MHz to 400MHz) Closed loop current probe • Test Method In this test configuration the current injected in to either the input pin or the tracking output pin is increased until a reset output is generated. These two pins are the most critical as they typically will connect to a module through long lengths of wire most likely to pick up high frequency energy. Figure 10 illustrates examples of test results on the LM9073 with both types of modulation. These results are just examples as actual results in any given application will depend on numerous external factors such as component selection, pc board layout, etc. The current power of the injected signal is expressed indB relative to 1mA (i.e. 40dBmA = 100mA) Figure 10. Examples of BCI Test BCI Susceptibility, Modulation 1 (CW) BCI Susceptibility, Modulation 2 (CW) (1kHz, 80% AM Modulation) DS101296-25 DS101296-26 www.national.com 16 LM9073 Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM9073S NS Package Number TS11B 17 www.national.com LM9073 Dual High Current Low-Dropout System Regulator Physical Dimensions inches (millimeters) unless otherwise noted (Continued) Order Number LM9073T NS Package Number TA11B 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) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 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: ap.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.