Block Diagram

10130522

Application Information

The LM9074 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 LM9074 has been tested and shown to con-

tinue 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 V

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.

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