RT6908
SDA
t
t
t
SU, STA
BUF
SU, DAT
t
t
SP
HD, STA
t
LOW
t
t
SU, STO
HD, DAT
SCL
t
HIGH
t
HD, STA
t
t
F
R
START
Condition
Repeated Start
Condition
STOP
Condition
START
Condition
Figure 3. I2C Interface TimingDiagram
Functional Pin Description
Pin No.
Pin Name
Pin Function
1, 13, 17,
41(Exposed Pad)
Power Ground. The exposed pad must be soldered to a large PCB and
connected to PGND for maximum thermal dissipation.
PGND
2
FBB1
Feedback Input for Buck1 Converter.
Compensation Pin for Buck1 Converter. This pin is the output node of the
error amplifier.
3
COMP1
4
5
6
7
8
RSTB
SDA
Voltage Detector Open-Drain Output.
2
I C Compatible Serial Data Input/Output.
2
SCL
I C Compatible Serial Clock Input.
VDET
AVDD
Voltage Detector Input.
Output Sense Pin for Boost Converter AVDD.
Gate Drive. Used to control an external MOSFET switch to provide input to
output isolation of AVDD.
9
GD
10
11
LXI
Isolation Switch Input.
Boost Converter (AVDD) Compensation. Connect a compensation network
to ground.
COMP
A0
2
12
I C Compatible Device Address Bit 0.
Boost Converter (AVDD) Switch. Connect an inductor between this pin and
input voltage source.
14, 15, 16
LX
18
19
20
21
VGL
Output Sensing Pin of VGL Negative Charge Pump.
Output Sensing Pin of VGH Positive Charge Pump.
VGH
DRVP
DRVN
Base Drive of External PNP Transistor for VGH Positive Charge Pump.
Base Drive of External NPN Transistor for VGL Negative Charge Pump.
Voltage Detector Delay Capacitor Connection. Connect capacitor from this
pin to ground.
22
CRST
23
24
COMP2
FBB2
Compensation Pin for Buck2 Converter.
Feedback Input for Buck2 Converter.
Current Limit Adjustment for Buck2 Converter. Connect a resistor from
ILIMIT2 to AGND to adjust the current limit threshold below 300mV.
25
ILIMIT2
26
DLB2
NC
Low Side Gate Driver Output for Buck2 Converter.
Not Internal Connected. Should be floating or connected to GND
27, 37
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is a registered trademark of Richtek Technology Corporation.
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4
DS6908-01 March 2013
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
