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LM9072
Dual Tracking Low-Dropout System Regulator
General Description
The LM9072 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%maximum tolerance5Voutputat 350 mA witha low dropout characteristic. The second regulator provides a 5V output that tracks the main regulator output voltage within 1.5
%
with load currents up to 80 mA. The tracking output is ideal
for use in powering remotely located sensors with outputs
that are ratiometric to the main system supply. This output is
fully protected from short circuits to ground or the unregulated input supply (ignition or battery potentials in automotive
applications).
The LM9072 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 to allow a system to remain powered after ignition
has been switched OFF.
For EMC concerns the LM9072 remains fully operational
and does not generate false rest signals while subjected to,
1 MHz to 400 MHz bulk current injection signals greater than
100 mA on the input supply and tracking output lines.
Features
n Two 5V regulated outputs:
— 350 mA, 2%Main output
— 80 mA, 1.5%Tracking output
n Good EMI (1 MHz to 400 MHz, BCI) immunity
n Separate ON/OFF and Keep-Alive control inputs
n Less than 100 µA quiescent current in OFF state
n Programmable delayed reset output
n Input transient protection over 60V to −45V
n Tracking output protected from shorts to battery
n Less than 1V dropout at full load
n −40˚C to +125˚C operating temperature range
n Surface mount TO-263 Power Package and Standard
TO-220 power package
Typical Applications
n Automotive module supply power conditioning
n Remote sensor biasing
n Ratiometric to supply sensor detection
n Continuous operation for save routines and EPROM
programming after power down command
n Safety related systems— EMC operational
Connection Diagrams and Ordering Information
9-Lead TO-263
Surface Mount Power Package
DS012906-2
Backside metal is internally connected to ground.
Order Number LM9072S
See NS Package Number TS9A
9-Lead TO-220 Package
DS012906-3
Tab is internally connected to ground.
Order Number LM9072T
See NS Package Number TA9A
December 1999
LM9072 Dual Tracking Low-Dropout System Regulator
© 1999 National Semiconductor Corporation DS012906 www.national.com
Page 2
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 (Continuous) −45V to 45V
Input Voltage (Transient, t ≤ 400 ms) 60V
Forced Output Voltages
Main Output −0.3V to 7V
Tracking Output −0.3V to 27V
ON/OFF Input Voltage (Note 6) −0.3V to 16V
ON/OFF Input Current
±
20 mA
Keep Alive In, Reset Out,
C
DELAY
Voltage −0.3V to 7V
Junction Temperature 150˚C
Storage Temperature Range −65˚C to +150˚C
ESD Susceptibility (Note 2) 2000V
Lead Temperature
(Soldering, 10 seconds) 265˚C
Operating Ratings (Note 1)
Input Voltage Range 6V to 27V
Ambient Temperature Range −40˚C to +125˚C
Thermal Resistance, θ
J-C
4˚C/W
Thermal Resistance, θ
J-A
43˚C/W
Electrical Characteristics
6.0V ≤ VIN≤ 19V, T
CASE
=
25˚C, unless otherwise specified. C
OUT
≥ 6 µF with 0.3Ω≤ESR ≤ 3Ω on each regulator output.
Symbol Parameter Conditions Min Max Units
MAIN REGULATOR
V
MAIN
Output Voltage 5 mA ≤ I
LOAD
≤ 350 mA
−40˚C ≤ T
CASE
≤ 125˚C
4.9 5.1 V
19V ≤ V
IN
≤ VSD,
5mA≤I
LOAD
≤ 350 mA
−40˚C ≤ T
CASE
≤ 125˚C
4.8 5.2 V
R
MLOAD
Load Regulation V
IN
=
16V, 5 mA ≤ I
LOAD
≤ 350 mA 25 mV
R
MLINE
Line Regulation I
LOAD
=
350 mA, 8V ≤ V
IN
≤ 16V 25 mV
V
MDO
Dropout Voltage, VIN–V
MAIN
V
IN
>
5.5V, 5 mA ≤ I
LOAD
≤ 350 mA
(Note 5)
0.8 V
V
SD
Overvoltage Shutdown Threshold 30 36 V
I
MSC
Output Short Circuit Current R
L
=
1Ω 450 1000 mA
R
MRR
Ripple Rejection V
IN
=
9V, 50 ≤ Freq ≤ 20 kHz,
V
RIPPLE
=
4V
P-P
40 dB
TRACKING REGULATOR
V
TRACK
Output Voltage 1 mA ≤ I
LOAD
≤ 80 mA
−40˚C ≤ T
CASE
≤ 125˚C
4.85 5.15 V
19V ≤ V
IN
≤ V
SD
1mA≤I
LOAD
≤ 80 mA
−40˚C ≤ T
CASE
≤ 125˚C
4.725 5.275 V
V
ERROR
Output Tracking Error
(V
MAIN–VTRACK
)
1mA≤I
LOAD
≤ 80 mA
−50 50 mV
V
TDO
Dropout Voltage,
V
IN–VTRACK
V
IN
>
5.5V, 1 mA ≤ I
LOAD
≤ 80 mA
(Note 5)
0.8 V
V
SD
Overvoltage Shutdown Threshold 30 36 V
I
TSC
Output Short Circuit Current R
L
=
1Ω 200 mA
V
TSC
Output Short Circuit Voltage No Effect On Other Functions −2 27 V
R
TRR
Ripple Rejection V
IN
=
9V, 50 ≤ Freq ≤ 20 kHz,
V
RIPPLE
=
4V
P-P
40 dB
INPUT CURRENT
I
qOFF
Quiescent Input Current with
Both Regulators OFF
8V ≤ VIN≤ 16V 40 µA
16V ≤ V
IN
≤ 42V 10 mA
I
q
No Load Quiescent Current 8V ≤ VIN≤ 19V, I
L
=
0mA 15 mA
In
ON
Additional Input Current with
Both Regulators ON
V
IN
>
8V, I
Ltotal
=
I
Lmain+ILtrack
I
Ltotal
=
350mA+80mA=430 mA
1.2 x I
Ltotal
Iin
do
Additional Input Current in Dropout 0V<V
IN
<
8V, (Note 4)
I
Ltotal
=
I
Lmain+ILtrack
I
Ltotal
=
350mA+80mA=430 mA
1.5 x I
Ltotal
LM9072
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Electrical Characteristics (Continued)
6.0V ≤ VIN≤ 19V, T
CASE
=
25˚C, unless otherwise specified. C
OUT
≥ 6 µF with 0.3Ω≤ESR ≤ 3Ω on each regulator output.
Symbol Parameter Conditions Min Max Units
RESET OUTPUT
V
THRL
Low Switching Threshold V
MAIN
Output Controls Reset 4.45 4.75 V
V
THRH
High Switching Threshold V
MAIN
Output Controls Reset 5.40 5.75 V
V
LOW
Logic Low Output Voltage 1V ≤ V
MAIN
≤ V
THRL
,
R
RESET
=
50 kΩ to V
MAIN
0.4 V
V
HIGH
Logic High Output Voltage Normal Operation,
V
THRL
≤ V
MAIN
≤ V
THRH,ISOURCE
=
0
V
MAIN
–
50 mV
V
MAIN
V
R
P-U
Internal Output Pull-Up Resistance 2.4 6.0 kΩ
T
DELAY
Reset Delay Interval C
DELAY
=
0.1 µF (Low Leakage),
I
DELAY
for Charging the Delay
Capacitor is Typically 6 µA
35 70 ms
T
RISE
Output Rise Time From 10%V
MAIN
to 90%V
MAIN
C
LRESET
=
50 pF
1.5 µs
T
FALL
Output Fall Time From 90%V
MAIN
to 10%V
MAIN
C
LRESET
=
50 pF
0.5 µs
CONTROL INPUTS
V
ON
ON Threshold for ON/OFF Input R
SERIES
=
22 kΩ 3.5 4.5 V
V
OFF
OFF Threshold for ON/OFF Input R
SERIES
=
22 kΩ (Note 3) 1.5 2.5 V
I
ON/OFF
ON/OFF Input Current 1.4V ≤ V
ON/OFF
≤ 4.5V 1 12 µA
−0.3V ≤ V
ON/OFF
≤ 7V (Note 6) −1 5 mA
ON
K-A
Turn ON Threshold for Keep Alive
Input
2V
OFF
K-A
Turn OFF Threshold for Keep Alive
Input
(Note 3)
0.8 V
R
P-D
Pull-Down Resistance at Keep
Alive Input
0V ≤ V
K-A
≤ 5V
540kΩ
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device remains functional but do not guarantee specific performance limits. For guaranteed specifications and test conditions see the Electrical Characteristics.
Note 2: Human body model, 150 pF capacitor 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 quiescentcurrent will increase when the regulators are in dropout conditions. The amount of additional input currents is a direct function of the total
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 both regulators will output at least 4.7V with an input voltage of only 5.5V.
Note 6: The ON/OFF input is internally clamped to a 7V zener diode througha1kΩresistor.
LM9072
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Typical Performance Characteristics (T
A
=
25˚C unless otherwise specified)
Turn-ON Characteristic
DS012906-4
Turn-OFF Characteristic
DS012906-5
Normalized Main Output
Voltage vs Temperature
DS012906-6
Quiescent Input Current vs
Input Voltage
DS012906-7
Main Output Voltage at
Input Voltage Extremes
DS012906-8
Input Current vs Input
Voltage (Regulators OFF)
DS012906-9
Tracking Output Short
Circuit Current
DS012906-10
Main Regulator Dropout
Voltage vs Load Current
DS012906-11
Output Short Circuit
Current vs Temperature
DS012906-12
LM9072
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Typical Performance Characteristics (T
A
=
25˚C unless otherwise specified) (Continued)
Operational Characteristics
Control Logic Truth Table
ON/OFF
Input
Keep-Alive
Input
Main
Output
Voltage
Tracking
Output
Voltage
Reset
Output
Operating Condition
L L 0V 0V 0V OFF, Input Current
<
100 µA
↑
L5V5V
↑
After Delay Outputs Turn ON, Power ON Delayed Reset
H X 5V 5V 5V Normal ON Condition
HX
<
4.45V
<
4.45V 0V Main Output Pulled Out of Regulation, Reset Flag Generated
↓
H 5V 5V 5V Keep-Alive, Continued Normal Operation
L
↑
5V 5V
↑
After Delay Outputs Turned ON by Keep-Alive Input
Reverse Battery
Input Current
DS012906-13
Maximum Power
Dissipation
DS012906-14
Output Capacitor ESR
DS012906-15
DS012906-16
LM9072
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Application Information
PIN DESCRIPTION AND FUNCTIONALITY
The LM9072 is a precision dual tracking voltage regulator
optimized for use in powertrain module applications but will
also find use in a wide variety of automotive and industrial
applications where precision supply regulation is required in
harsh operating environments. The following will describe
the functionality of each of the package pins.
INPUT VOLTAGE (Pin 3)
The LM9072 has been designed to connect directly to the ignition or battery supply in automotive applications. For this
type of supply the regulator has been designed to withstand
up to +60V and −45V supply transients such as load dump.
An overvoltage shut down protection scheme 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 24 V
DC
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.
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 15 mA maximum quiescent current for biasing internal circuitry. During
dropout conditions (V
IN
<
5.5V) the additional input current
can rise to 50%of the total load current. With less than 4V
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 100 µA.
MAIN OUTPUT (Pin 9)
The Main Output regulator provides a well controlled (3%tolerance maximum) 5V supply line with a total load current
ranging up to 350 mA. 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
500 mA and 1A. The Main output can also withstand a short
circuit to potentials up to 7V.
To maintain stability of this supply line an output bypass capacitor is required. This capacitor must be at least 6 µF 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. Feedback from the Main Output is also used to
control the output voltage of the tracking regulator.
TRACKING OUTPUT (Pin 4)
The Tracking Output regulator is a key feature of the
LM9072. This output provides a voltage that directly tracks
the main output voltage within 1.5%. This 80 mA output is
provided to bias sensors and other devices located external
to the main system module.
For providing remote power the Tracking 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 affect the operation of the main supply nor generate a reset of the system.
The tracking characteristic allows for ratiometric operation of
sensors by providing power that is directly proportional to the
system supply.Similar to the main output a bypass capacitor
is required for stability. This capacitor should also be greater
than 6 µF with an ESR between 0.3Ω and 3Ω.
DS012906-17
FIGURE 1. Circuit Block Diagram
LM9072
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Application Information (Continued)
RESET OUTPUT (Pin 6)
The Reset Output is an active low logic signal provided to reset a system microcontroller on power up and in the event
that the Main Output supply falls out of regulation. This output is guaranteed to provide a logic low level (
<
0.4V) whenever the Main Output supply is below 4.45V 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 to ground and a
passive pull-up (througha4kΩresistor) 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 500 µA), but with 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 selection of the delay capacitor.
DELAY CAPACITOR (Pin 7)
The Delay Capacitor (C
DELAY
) controls a time interval that
the Reset Output remains low after the Main Output has established normal operating condition. This feature holds the
system inreset for a time to allow all load circuitry to be properly biased 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 or exceeds 5.5V typically. If this is true (at power-on, for
example) the control logic turns ON the discharge transistor
and holds C
DELAY
low (at 0.9V). Comparator C4 then outputs
a logic low system Reset signal within 2 µs after detecting
the out of regulation condition.
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
C
DELAY
is charged positively by an internal 6 µA current
source. The Reset Output will remain low un 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 selection of C
DELAY
and can be deter-
mined from the following equation:
T
DELAY
=
(0.5 x 10
6
)•C
DELAY
Typically a 0.1 µF capacitor will produce a delay interval of
50 ms.
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 C
DELAY
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.
ON/OFF INPUT (Pin 1)
The ON/OFF Input enables both the Main and Tracking outputs. In a typical application this input is connected to the input supply through a series resistor (nominally 22 kΩ) 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 1 kΩ resistor. The external series resistor
together with an optional 0.1 µF capacitor to ground are optional to provide filtering and current limiting to withstand any
transients that may appear on the input supply in order to
maintain normal operation of the system.
The switching threshold of the ON/OFF comparator has 2V
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 taken below 2V.
DS012906-18
FIGURE 2. Reset Generator
LM9072
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Application Information (Continued)
KEEP-ALIVE INPUT (Pin 8)
This CMOS logic level compatible input provides a system
with the ability to control its 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 neces-
sary 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.
Asecond use ofthe Keep-Alive Input canbe from other modules which need information from the module powered by
the LM9072,
Figure 3
. A CMOS logic high level (>2V) on
this input will power up the system as needed independent
from the normal ON/OFF switch.
System Keep-Alive Operation
Figure 4
illustrates the basic concept of Keep-Alive operation. The LM9072 provides 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 1. 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 C
DELAY
.
Once normal operation of the system begins, the controller
needs to set an output line connected to the Keep-Alive input, pin 8, 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 willremain 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 LM9072
powers down to a low quiescent current mode with less than
100 µA drawn from the input supply.
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, a simple logic scheme
shown in
Figure 5
can be used. With this circuitry the Reset
output from the LM9072 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
LM9072. The inverted Reset signal provides a logic 1 to the
Keep-Alive input of the LM9072.
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 returns 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.
DS012906-19
FIGURE 3. Remote ON/OFF Control
LM9072
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Application Information (Continued)
DS012906-20
FIGURE 4. Basic Keep-Alive Operation
LM9072
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Application Information (Continued)
Safety Latch-OFF
To address a system FMEA (Failure Mode Effects Analysis)
issue the Keep-Alive high level should be derived from the
Tracking output regulator as shown in
Figure 6
. The issue
stems from the “what-if” scenario whereby the system is in
the Keep-Alive state and there is a short to ground on the
Tracking Output regulator. If this output is powering remote
sensors or systems, this becomes a more highly possible
fault condition. Since a short on the Tracking output does not
affect the Main output, which, if used to provide the
Keep-Alive input signal, would remain ON and draw 120 mA,
the short circuit current of the Tracking regulator, from the input supply.
Using the Tracking output supply for Keep-Alive would prevent Keep-Alive operation during a short to ground fault and
the excessive drain on the input supply.The inversion by the
transistor will require a low level from the controller to allow
Keep-Alive operation. The 24 kΩ pull-up resistor provides
current limiting in the event of a Tracking output short to the
unregulated/battery input supply.
DS012906-21
FIGURE 5. Simple Logic Configuration to Provide ON/OFF Sensing
LM9072
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Application Information (Continued)
Input Stability
Low dropout voltage regulators which utilize a PNP power
transistor usually exhibit a large increase in current when in
dropout (V
IN
<
5.5V). This increase is caused by the saturation characteristics (β reduction) of the PNP transistor. To
significantly minimize this increase in current the LM9072
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 (
>
200 mA) 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
500 mV/ms it will move through the dropout region of the
regulator (V
IN
of 3V to 5.5V) too quickly for an oscillation to
be established.
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 straightforward addition of
a larger valued electrolytic capacitor could suffice. in this
case however,if reverse battery connections are a 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.
DS012906-22
FIGURE 6. Safety Latch-OFF
DS012906-23
FIGURE 7. Input Bypassing
LM9072
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Application Information (Continued)
Thermal Management
The LM9072 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 in 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 shut down. 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 and can optimize the PC board surface area required.
Electro-Magnetic Compatibility (EMC)
The LM9072 offers good immunity to high frequency interference in a standard Bulk Current Injection (BCI) test
(ISO11452Part 4 test method). The following test conditions
and configuration (
Figure 9
) can be used to observe this per-
formance.
Frequency Range 1 MHz to 400 MHz
Modulation 1 CW (no modulation)
Modulation 2 1 kHz sine wave, 80%AM
Dwell Time 1 second
Frequency Steps 1 MHz (from 1 MHz to 10 MHz)
2 MHz (from 10 MHz to 200 MHz)
20 MHz (from 200 MHz to 400 MHz)
Test Method Closed loop current probe
In this test configuration the current injected into 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 LM9072 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 in dB relative
to 1 mA (i.e., 40 dBmA=100 mA).
DS012906-24
FIGURE 8. Typical TO-263 PC Board Heatsinking
LM9072
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Application Information (Continued)
DS012906-25
FIGURE 9. Bulk Current Injection Test Configuration
BCI Susceptibility, Modulation 1 (CW)
DS012906-26
BCI Susceptibility Moduiatlon 2 (1 kHz, 80%AM
modulation)
DS012906-27
FIGURE 10. Examples of BCI Test Results
LM9072
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Page 14
Physical Dimensions inches (millimeters) unless otherwise noted
Order Number LM9072T
NS Package Number TA9A
LM9072
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
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.
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.
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Order Number LM9072S
NS Package Number TS9A
LM9072 Dual Tracking Low-Dropout System Regulator
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.
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