RT9079

2

DS9079-03 March 2019

www.richtek.com

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Copyright 2019 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Pin Description

Functional Block Diagram

Pin No.

Pin Name

Pin Function

1

VCC

Supply voltage input.

2

GND

Ground.

3

NC

No internal connection.

4

EN

Enable control input.

5

VOUT

Output of the regulator.

VCC

GND

EN

VOUT

-

Current/Thermal

Sense

Bandgap

Reference

R1

R2

Operation

Basic Operation

The RT9079 is a high input voltage linear regulator designed

especially for low external component systems. The input

voltage range is from 3.5V to 36V.

The minimum required output capacitance for stable

operation is 1

μF effective capacitance after consideration

of the temperature and voltage coefficient of the capacitor.

Output Transistor

The RT9079 builds in a P-MOSFET output transistor which

provides a low switch-on resistance for low dropout voltage

applications.

Error Amplifier

The ErrorAmplifier compares the internal reference voltage

with the output feedback voltage from the internal divider,

and controls the Gate voltage of P-MOSFET to support

good line regulation and load regulation at output voltage.

Enable

The RT9079 delivers the output power when it is set to

enable state. When it works in disable state, there is no

output power and the operation quiescent current is almost

zero.

Current Limit Protection

The RT9079 provides current limit function to prevent the

device from damages during over-load or shorted-circuit

conditions. This current is detected by an internal sensing

transistor.

Over-Temperature Protection

The over-temperature protection function turns off the P-

MOSFET when the junction temperature exceeds 150°C

(typ.) and the output current exceeds 4mA. Once the

junction temperature cools down by approximately 20°C,

the regulator automatically resumes operation.