LM9070M National Semiconductor, LM9070M Datasheet - Page 7

• Manufacturer Part Number: LM9070M
• Description: Low-Dropout System Voltage Regulator with Keep-Alive ON/OFF Control
• Manufacturer: National Semiconductor

ON/OFF
Input
Control Logic Truth Table
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 con-
tinue to provide a regulated output and, not generate an er-
roneous 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 rec-
ommended).
This regulator is suitable for applications where continuous
connection to the battery is required ( Refer to the Typical Ap-
plication Circuit ). ON/OFF control of the regulator and sys-
tem can be accomplished by switching the ON/OFF input to
the battery or ignition supply V
H
H
L
L
Keep-Alive
Input
X
X
X
H
X
L
L
L
V
OUT
V
Voltage
OUT
Output
IN
0V
5V
5V
0V
5V
5V
supply through a SPST
−300 mV
4V
after delay
Output
Reset
H
H
H
L
L
L
L
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 V
nected 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.
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
FIGURE 1. Typical Application Circuit
IN
and the ON/OFF input pins to be con-
Operating Condition
DS012831-22
www.national.com
DS012831-23