RT8249A/B/C

3

DS8249A/B/C-02

June 2014

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Copyright

2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

CS1

Current Limit Setting. Connect a resistor to GND to set the threshold for Channel

1/8th the voltage seen at CS1 over a 0.2V to 2V range. There is an internal 50

A

current source from LDO5 to CS1.

2

FB1

Feedback Voltage Input for Channel 1. Connect FB1 to a resistive voltage divider

from VOUT1 to GND to adjust output from 2V to 5.5V.

3

LDO3

3.3V Linear Regulator Output. It is always on when VIN is higher than VINPOR

threshold.

4

FB2

Feedback Voltage Input for Channel 2. Connect FB2 to a resistive voltage divider

from VOUT2 to GND to adjust output from 2V to 5.5V.

5

CS2

Current Limit Setting. Connect a resistor to GND to set the threshold for Channel

1/8th the voltage seen at CS2 over a 0.2V to 2V range. There is an internal 50

A

current source from LDO5 to CS2.

6

EN2

Enable Control Input for Channel 2.

7

PGOOD

Power Good Indicator Output for Channel 1 and Channel 2. (Logical AND)

8

PHASE2

Switch Node of Channel 2 MOSFETs. PHASE2 is the internal lower supply rail for

the UGATE2 high-side gate driver. PHASE2 is also the current-sense input for the

Channel 2.

9

BOOT2

Bootstrap Supply for Channel 2 High-Side Gate Driver. Connect to an external

capacitor according to the typical application circuits.

10

UGATE2

High-Side Gate Driver Output for Channel 2. UGATE2 swings between PHASE2

and BOOT2.

11

LGATE2

Low-Side Gate Driver Output for Channel 2. LGATE2 swings between GND and

LDO5.

12

VIN

Power Input for 5V and 3.3V LDO Regulators and Buck Controllers.

13

LDO5

5V Linear Regulator Output. LDO5 is also the supply voltage for the low-side

MOSFET and analog supply voltage for the device.

14

BYP1

Switch-over Source Voltage Input for LDO5.

15

LGATE1

Low-Side Gate Driver Output for Channel 1. LGATE1 swings between GND and

LDO5.

16

UGATE1

High-Side Gate Driver Output for Channel 1. UGATE1 swings between PHASE1

and BOOT1.

17

BOOT1

Bootstrap Supply for Channel 1 High-Side Gate Driver. Connect to an external

capacitor according to the typical application circuits.

18

PHASE1

Switch Node of Channel 1 MOSFETs. PHASE1 is the internal lower supply rail for

the UGATE1 high-side gate driver. PHASE1 is also the current sense input for the

Channel 1.

VCLK

(RT8249A/B)

Oscillator Output for Charge Pump.

19

SKIPSEL

(RT8249C)

PWM Operating Mode Selection.

Diode-emulation Mode : Connect to LDO3

Audio Skipping Mode : Short to GND

20

EN1

Enable Control Input for Channel 1.

21

(Exposed Pad)

GND

Ground. The exposed pad must be soldered to a large PCB and connected to

GND for maximum power dissipation.