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-inputlogiccontrolschemeisusedtoenableor
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 toremainoperational and not generate false reset signals
when subjected to high levels of RF energy (300V/m from
2 MHz to 400 MHz).
Features
n Automotive application reliability
n 3%output voltage tolerance
n Insensitive to radiated RFI
n Dropout voltage less than 800 mV with 250 mA output
current
n Externally programmed reset delay interval
n Keep-alive feature with 2 logic control inputs
n 60V Load dump transient protection
n Thermal shutdown
n Short circuit protection and disable safety features
n Reverse battery protection
n Low OFF quiescent current, 50 µA maximum
n Wide operating temperature range −40˚C to +125˚C
n TO-263 and 20-pin power surface mount packages
n Lead form compatible with TLE4267 TO-220 regulator
(package TA07D)
Connection Diagrams and Ordering Information (Top View)
7-Lead TO-263
Surface Mount Package
DS012831-1
Backside metal is internally connected to ground.
Order Number LM9070S
See NS Package Number TS7B
20-Pin SO Package
DS012831-2
Order Number LM9070M
See NS Package Number M20B
December 1999
LM9070 Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control
© 1999 National Semiconductor Corporation DS012831 www.national.com
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
LM9070
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Absolute Maximum Ratings (Note 1)
Input Voltage
ON/OFF, Keep-Alive Inputs
(through 1 kΩ)
DC Input Voltage −26V to +26V
Positive Input Transient (t
<
100 ms) 60V
Negative Input Transient (t
<
1 ms) −50V
Reset Output Sink Current 5 mA
Power Dissipation Internally Limited
Junction Temperature 150˚C
ESD Susceptibility (Note 2) 12 kV, 2 kV
Lead Temperature
(Soldering, 10 seconds) 260˚C
Storage Temperature −50˚C to +150˚C
Operating Ratings (Note 1)
Input Voltage 6V to 26V
Ambient Temperature −40˚C to +125˚C
θjc, TO-220, TO-263 Packages 3˚C/W
θja, TO-220, TO-263 Packages 43˚C/W
θj-pins, SO20 Package 25˚C/W
θja, SO20 Package 85˚C/W
Electrical Characteristics
The following specifications apply for V
CC
=
6V to 26V, −40˚C ≤ T
A
≤ 125˚C, unless otherwise specified. C
OUT
=
47 µFd with an
ESR
<
3Ω.C
IN
=
1 µFd.
Symbol Parameter Conditions Min Max Units
REGULATOR OUTPUT
V
OUT
Output Voltage 5 mA ≤ I
OUT
≤ 250 mA 4.85 5.15 V
∆V
OUT
Line Line Regulation I
OUT
=
5 mA, 9V ≤ V
IN
≤ 16.5V
I
OUT
=
5 mA, 6V ≤ V
IN
≤ 26V
25
50
mV
mV
∆V
OUT
Load Load Regulation V
IN
=
14.4V, 5 mA ≤ I
OUT
≤ 250 mA 50 mV
Iq Quiescent Current V
ON/OFF
≤ V
IN
I
OUT
=
5mA
I
OUT
=
250 mA, V
IN
≥ 8V
I
OUT
=
5 mA, V
IN
=
5V
I
OUT
=
250 mA, V
IN
=
6V
4
25
10
50
mA
mA
mA
mA
Ioff OFF Quiescent Current V
IN
≤ 16.5V, Regulator OFF
−40˚C ≤ T
J
≤ 60˚C
60˚C ≤ T
J
≤ 135˚C
20
60
µA
µA
Vdo Dropout Voltage I
OUT
=
5mA
I
OUT
=
250 mA
300
800
mV
mV
Isc Short Circuit Current R
L
=
1Ω 0.4 1.5 A
RR Ripple Rejection fripple=120 Hz, Vripple=1 Vrms
I
OUT
=
50 mA 60 dB
Voth
OFF
Safety V
OUT
Latch-OFF Threshold In Keep-Alive mode
V
ON/OFF
=
0V, V
KA
=
0V 4 4.5 V
OVthr Overvoltage Shutdown Threshold 27 V
Vo Transient V
OUT
during Transients VINPeak ≤ 60V,
R
L
=
100Ω, τ=100 ms
7V
RESET OUTPUT
Vth Threshold Voltage ∆V
OUT
Required to Generate a
Reset Output
4.85V ≤ V
OUT
≤ 5.15V
−300 −500 mV
Vlow Reset Output Low Voltage Isink=1.6 mA, V
OUT
>
3.2V 0.4 V
1.4V ≤ V
OUT
≤ 3.2V 0.8 V
Vhigh Reset Output High Voltage 0.9 V
OUT
V
OUT
V
t
delay
Delay Time Cdelay=0.1 µFd 7 31 ms
I
delay
Charging Current for Cdelay 10 30 µA
Rpu Internal Pull-up Resistance 12 80 kΩ
CONTROL LOGIC
V
KA
low Low Input Threshold Voltage,
Keep-Alive Input
3.5V ≤ V
OUT
≤ 5.25V 0.3 V
OUT
0.5 V
OUT
V
LM9070
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Electrical Characteristics (Continued)
The following specifications apply for V
CC
=
6V to 26V, −40˚C ≤ T
A
≤ 125˚C, unless otherwise specified. C
OUT
=
47 µFd with an
ESR
<
3Ω.C
IN
=
1 µFd.
Symbol Parameter Conditions Min Max Units
CONTROL LOGIC
V
KA
high High Input Threshold Voltage,
Keep-Alive Input
3.5V ≤ V
OUT
≤ 5.25V 0.6 V
OUT
0.8 V
OUT
V
V
ON/OFF
low Low Input Voltage, ON/OFF Input Rseries=1kΩ −2 2 V
V
ON/OFF
high High Input Voltage, ON/OFF Input Rseries=1kΩ 426V
I
ON/OFF
Input Current, ON/OFF Input V
ON/OFF
≤ 4V 330 µA
4V
<
V
ON/OFF
<
7V 670 µA
V
ON/OFF
≥ 7V 10 mA
Rpu
KA
Internal Pull-up Resistance,
Keep-Alive Input
0V ≤ VIN≤ 26V
20 100 kΩ
Rpd
ON/OFF
Internal Pull-down Resistance
ON/OFF Input
0V ≤ V
ON/OFF
≤ 26V
50 210 kΩ
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 VINand
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 ca-
pacitor.
Reset Operation and Protection Features
DS012831-5
LM9070
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Typical Performance Characteristics (T
A
=
25˚C unless indicated otherwise)
Turn ON Characteristics
DS012831-6
Turn OFF Characteristics
DS012831-7
Normalized Output Voltage
vs Temperature
DS012831-8
Output Voltage at
Input Voltage Extremes
DS012831-9
Quiescent Current vs
Input Voltage
DS012831-10
Input Current vs
Input Voltage
Regulator Switched OFF
DS012831-11
Dropout Voltage vs
Temperature
DS012831-12
Reset Delay Time
vs Temperature
DS012831-13
Short Circuit Current
vs Temperature
DS012831-14
LM9070
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Typical Performance Characteristics (T
A
=
25˚C unless indicated otherwise) (Continued)
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 V
OUT
as the regulator turns
OFF.
Output Capacitor ESR
DS012831-15
Maximum Power Dissipation
(TO-220 Package)
DS012831-16
Maximum Power Dissipation
(TO-263 and SO-20 Packages)
DS012831-17
Simple ON/OFF control
(Keep-Alive input must be high to turn OFF output)
DS012831-18
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)
DS012831-19
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)
DS012831-20
Safety Latch OFF of V
OUT
when in Keep-Alive Mode
(ON/OFF going high required to turn Output back ON)
DS012831-21
LM9070
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Control Logic Truth Table
ON/OFF
Input
Keep-Alive
Input
Output
Voltage
Reset
Output
Operating Condition
L X 0V L Low quiescent current standby (OFF) condition
↑
X5V
↑
after delay Output turns ON
H X 5V H Normal ON condition
↓
H 0V L Output turns OFF
↓
L 5V H Output kept ON by Keep-Alive Input
↑
L 5V H Output remains ON (or turns ON)
HX∆V
OUT
≥ −300 mV L Output pulled out of regulation, reset flag generated
LL V
OUT
≤ 4V L Output latches OFF
Block Diagram
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 TypicalAp-
plication Circuit
). ON/OFF control of the regulator and system can be accomplished by switching the ON/OFF input to
the battery or ignition supply V
IN
supply through a SPST
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 V
IN
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.
DS012831-22
DS012831-23
FIGURE 1. Typical Application Circuit
LM9070
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Application Information (Continued)
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 V
CC
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 V
OUT
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.
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.
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 V
CC
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:
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 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 (V
IN
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.
DS012831-24
FIGURE 2. Control Logic Not Used
LM9070
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Application Information (Continued)
DS012831-25
LM9070
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Physical Dimensions inches (millimeters) unless otherwise noted
20-Lead (0.300" Wide) Molded Small Outline Package, JEDEC
Order Number LM9070M
NS Package Number M20B
LM9070
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
7-Lead Molded TO-220
Order Number LM9070T
NS Package Number TA07B
LM9070
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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
LM9070
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Notes
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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
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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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www.national.com
LM9070 Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control
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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