®
RT9611A/B
Synchronous Rectified Buck MOSFET Drivers
General Description
The RT9611A/B is a high frequency, synchronous rectified,
single phase dual MOSFET driver designed to adapt from
normal MOSFET driving applications to high performance
CPU VR driving capabilities.
The RT9611A/B can be utilized under both V
CC
= 5V or
V
CC
= 12V applications. The RT9611A/B also builds in an
internal power switch to replace external boot strap diode.
The RT9611A/B can support switching frequency efficiently
up to 500kHz. The RT9611A/B has the UGATE driving
circuit and the LGATE driving circuit for synchronous
rectified DC/DC converter applications. The driving rise/
fall time capability is designed within 30ns and the shoot
through protection mechanism is designed to prevent shoot
through of high side and low side power MOSFETs. The
RT9611A/B has PWM tri-state shut down and OD input
shut down functions which can force driver output into
high impedance.
The difference of the RT9611A and the RT9611B is the
propagation delay, t
UGATEpdh
. The RT9611B has
comparatively large t
UGATEpdh
than RT9611B. Hence, the
RT9611A is usually recommended to be utilized in
performance oriented applications, such as high power
density CPU VR or GPU VR.
The RT9611A/B comes in a small footprint with 8-pin
packages. The choice of packages type includes SOP-8,
SOP-8 (Exposed Pad) and WDFN-8EL 3x3.
Note :
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Features
Drive Two N-MOSFETs
Adaptive Shoot Through Protection
Embedded Bootstrap Diode
Support High Switching Frequency
Fast Output Rise Time
Tri-State Input for Bridge Shutdown
Disable Control Input
Small SOP-8, SOP-8 (Exposed Pad) and 8-Lead
WDFN Packages
RoHS Compliant and Halogen Free
Applications
Core Voltage Supplies for Desktop, Motherboard CPU
High Frequency Low Profile DC/DC Converters
High Current Low Voltage DC/DC Converters
Ordering Information
RT9611A/B
Package Type
S : SOP-8
SP : SOP-8 (Exposed Pad-Option1)
QW : WDFN-8EL 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
Long Dead Time
Short Dead Time
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9611A/B-03 June 2012
www.richtek.com
1
RT9611A/B
Pin Configurations
(TOP VIEW)
BOOT
PWM
OD
VCC
2
3
4
8
7
6
5
UGATE
PHASE
GND
LGATE
BOOT
PWM
OD
VCC
2
3
4
8
UGATE
PHASE
GND
LGATE
GND
9
7
6
5
SOP-8
BOOT
PWM
OD
VCC
1
2
3
4
9
GND
8
7
6
5
SOP-8 (Exposed Pad)
UGATE
PHASE
GND
LGATE
WDFN-8EL 3x3
Marking Information
RT9611xGS
RT9611xGS : Product Number
RT9611xGSP
RT9611xGSP : Product Number
x : A or B
YMDNN : Date Code
RT9611x
GSYMDNN
RT9611x
GSPYMDNN
x : A or B
YMDNN : Date Code
RT9611xZS
RT9611xZS : Product Number
RT9611xZSP
RT9611xZSP : Product Number
x : A or B
YMDNN : Date Code
RT9611x
ZSYMDNN
RT9611x
ZSPYMDNN
x : A or B
YMDNN : Date Code
RT9611AGQW
02= : Product Code
YMDNN : Date Code
RT9611BGQW
04= : Product Code
YMDNN : Date Code
02=YM
DNN
04=YM
DNN
RT9611AZQW
02 : Product Code
RT9611BZQW
04 : Product Code
YMDNN : Date Code
02 YM
DNN
04 YM
DNN
YMDNN : Date Code
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9611A/B-03 June 2012
RT9611A/B
Typical Application Circuit
ATX_12V
C6
1000µF
x3
RT9611A/B
ATX_12V
R1
10
C1
1µF
5V
PWM
3
2
OD
PWM
LGATE
GND
6
5
4 VCC
BOOT
UGATE
PHASE
1
8
7
R4
0
R5
2.2
Q2
C3
3.3nF
R2
1
C7
10µF
x4
V
IN
C2
1µF
R3
2.2
Q1
L1
1µH
V
CORE
+
C4
2200µF
x2
C5
10µF
x2
Timing Diagram
PWM
LGATE
t
pdlLGATE
90%
1.5V
t
pdlUGATE
1.5V
1.5V
UGATE
t
pdhUGATE
90%
1.5V
t
pdhLGATE
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9611A/B-03 June 2012
www.richtek.com
3
RT9611A/B
Functional Pin Description
Pin No.
SOP-8
1
2
3
4
5
6
7
8
SOP-8 (Exposed Pad) /
WDFN-8EL 3x3
1
2
3
4
5
6,
9 (Exposed Pad)
7
8
Pin Name
Pin Function
BOOT
PWM
OD
VCC
LGATE
GND
PHASE
UGATE
Floating Bootstrap Supply Pin for Upper Gate Driver.
Input PWM Signal for Controlling the Driver.
Output Disable. When low, both UGATE and LGATE are
driven low and the normal operation is disabled.
12V Supply Voltage.
Lower Gate Driver Output. Connected to gate of low side
power N-MOSFET.
Ground. The exposed pad must be soldered to a large
PCB and connected to GND for maximum power
dissipation.
Connect this pin to the source of the high side MOSFET
and the drain of the low side MOSFET.
Upper Gate Driver Output. Connected this pin to gate of
high side power N-MOSFET.
Function Block Diagram
VCC
Internal
3.6V
POR
15k
PWM
15k
Input
Disable
Bootstrap
Control
BOOT
Shoot-Through
Protection
12k
Turn Off
Detection
PHASE
12k
VCC
Shoot Through
Protection
12k
GND
LGATE
UGATE
OD
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9611A/B-03 June 2012
RT9611A/B
Absolute Maximum Ratings
(Note 1)
Supply Voltage, VCC ----------------------------------------------------------------------------------
−0.3V
to 15V
BOOT to PHASE ---------------------------------------------------------------------------------------
−0.3V
to 15V
PHASE to GND
DC ----------------------------------------------------------------------------------------------------------
−5V
to 15V
< 200ns ---------------------------------------------------------------------------------------------------
−10V
to 30V
LGATE
DC ---------------------------------------------------------------------------------------------------------- (GND
−
0.3V) to (V
CC
+ 0.3V)
< 200ns ---------------------------------------------------------------------------------------------------
−2V
to (V
CC
+ 0.3V)
UGATE ---------------------------------------------------------------------------------------------------- (V
PHASE
−
0.3V) to (V
BOOT
+ 0.3V)
< 200ns --------------------------------------------------------------------------------------------------- (V
PHASE
−
2V) to (V
BOOT
+ 0.3V)
PWM Input Voltage ------------------------------------------------------------------------------------ (GND
−
0.3V) to 7V
OD ---------------------------------------------------------------------------------------------------------- (GND
−
0.3V) to 7V
Power Dissipation, P
D
@ T
A
= 25°C
SOP-8 ----------------------------------------------------------------------------------------------------- 0.833W
SOP-8 (Exposed Pad) -------------------------------------------------------------------------------- 1.333W
WDFN-8EL 3x3 ----------------------------------------------------------------------------------------- 1.429W
Package Thermal Resistance (Note 2)
SOP-8,
θ
JA
----------------------------------------------------------------------------------------------- 120°C/W
SOP-8 (Exposed Pad),
θ
JA
--------------------------------------------------------------------------- 75°C/W
SOP-8 (Exposed Pad),
θ
JC
-------------------------------------------------------------------------- 15°C/W
WDFN-8EL 3x3,
θ
JA
------------------------------------------------------------------------------------ 70°C/W
WDFN-8EL 3x3,
θ
JC
----------------------------------------------------------------------------------- 8.2°C/W
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------ 260°C
Junction Temperature ---------------------------------------------------------------------------------- 150°C
Storage Temperature Range -------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) --------------------------------------------------------------------------- 2kV
Recommended Operating Conditions
(Note 4)
Supply Voltage, VCC ---------------------------------------------------------------------------------- 12V ±10%
Junction Temperature Range -------------------------------------------------------------------------
−40°C
to 125°C
Ambient Temperature Range -------------------------------------------------------------------------
−40°C
to 85°C
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9611A/B-03 June 2012
www.richtek.com
5
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