RT9184ACH View Datasheet(PDF) - Richtek Technology

Part Name

Description

Manufacturer

RT9184ACH

500mA Dual LDO Regulator

Richtek Technology 

Preliminary

RT9184

Polymide Tape

Gold Wire

Die

VIN

VOU T

Fig. 2 External Schottky Diode to Prevent Internal

Diode Turning on

Power Dissipation and PCB Layout Note

The maximum power dissipation of RT9184 depends

on the thermal resistance from the case to circuit

board, the temperature difference between the die

junction and ambient air, and the rate of airflow. The

power dissipation across the device is

P = IOUT (VIN - VOUT).

The maximum power dissipation is:

PMAX = (TJ - TA) / θJA

where TJ - TA is the temperature difference between

the RT9184 die junction and the ambient

environment, θJA is the thermal resistance from the

junction to the ambient environment. The GND pin of

the RT9184 performs the dual function of providing

an electrical connection to ground and channeling

heat away. Connect the GND pin to ground using a

large pad or ground plane.

The RT9184 is assembled by power SOP-8 package

with direct slug solder to PCB (Fig.3). This structure

offers a low thermal resistance of junction to case

(θJC) and can dissipate the heat away by proper PCB

layout (a proper θCA, thermal resistance of case to

ambient). Because the bottom slug of RT9184 plays

the role as ground, the footprint in Fig.4 is a typical

configuration for heat dissipating copper clad.

Medium power dissipations of up to 2W are easily

obtainable in practice with this configuration. The

heat dissipating copper area on the PCB can be

configured in various shapes and sized depending

upon the particular application.

Exposed Slug

Leadframe

Fig. 3 Power SOP-8 Structure

8

7

6

5

1

2

3

4

Fig. 4 Typical Footprint of RT9184

DS9184-00 March 2002

www.richtek-ic.com.tw

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