®
RT9612A/B
Synchronous-Rectified Buck MOSFET Driver
General Description
The RT9612A/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 RT9612A/B can be utilized under both V
CC
= 5V or
V
CC
= 12V applications. The RT9612A/B also builds in an
internal power switch to replace external boot strap diode.
The RT9612A/B can support switching frequency efficiently
up to 500kHz. The RT9612A/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
RT9612A/B has PWM tri-state shut down function which
can force driver output into high impedance.
The difference of the RT9612A and the RT9612B is the
propagation delay, t
UGATEpdh
. The RT9612B has
comparatively large t
UGATEpdh
than RT9612B. Hence, the
RT9612A is usually recommended to be utilized in
performance oriented applications, such as high power
density CPU VR or GPU VR. The RT9612A/B comes in a
small footprint with SOP-8, SOP-8 (Exposed Pad) and
WDFN-8EL 3x3.
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
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
RT9612A/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
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.
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9612A/B-03 June 2012
www.richtek.com
1
RT9612A/B
Pin Configurations
(TOP VIEW)
BOOT
PWM
NC
VCC
2
3
4
8
7
6
5
UGATE
PHASE
GND
LGATE
BOOT
PWM
NC
VCC
2
3
4
8
UGATE
PHASE
GND
LGATE
GND
9
7
6
5
SOP-8
BOOT
PWM
NC
VCC
UGATE
PHASE
GND
LGATE
SOP-8 (Exposed Pad)
8
1
2
3
4
GND
9
7
6
5
WDFN-8EL 3x3
Marking Information
RT9612xGS
RT9612xGS : Product Number
RT9612xGSP
RT9612xGSP : Product Number
x : A or B
YMDNN : Date Code
RT9612x
GSYMDNN
RT9612x
GSPYMDNN
x : A or B
YMDNN : Date Code
RT9612xZS
RT9612xZS : Product Number
RT9612xZSP
RT9612xZSP : Product Number
x : A or B
YMDNN : Date Code
RT9612x
ZSYMDNN
RT9612x
ZSPYMDNN
x : A or B
YMDNN : Date Code
RT9612AGQW
16= : Product Code
RT9612BGQW
17= : Product Code
YMDNN : Date Code
16=YM
DNN
17=YM
DNN
YMDNN : Date Code
RT9612AZQW
16 : Product Code
RT9612BZQW
17 : Product Code
YMDNN : Date Code
16 YM
DNN
17 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
DS9612A/B-03 June 2012
RT9612A/B
Typical Application Circuit
ATX_12V
C6
1000µF
x3
RT9612A/B
ATX_12V
R1
10
C1
1µF
3
PWM
2
NC
PWM
LGATE
GND
6
5
4 VCC
BOOT
UGATE
PHASE
R2
1 1
8
7
R4
0
R5
2.2
Q2
C3
3.3nF
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.
DS9612A/B-03 June 2012
www.richtek.com
3
RT9612A/B
Function Pin Description
SOP-8
1
2
3
4
5
6
7
8
Pin No.
SOP-8 (Exposed Pad)/ Pin Name
WDFN-8EL 3x3
1
BOOT
2
3
4
5
6,
9 (Exposed Pad)
7
8
PWM
NC
VCC
LGATE
GND
PHASE
UGATE
Pin Function
Floating Bootstrap Supply pin for Upper Gate Drive.
Input PWM Signal for Controlling the Driver.
No Internal Connection.
12V Supply Voltage.
Lower Gate Driver Output. Connect this pin 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 Drive Output. Connect this pin to gate of high side
power N-MOSFET.
Function Block Diagram
VCC
Internal
3.6V
POR
15k
PWM
15k
Tri-State
Detect
Bootstrap
Control
BOOT
Shoot-Through
Protection
12k
Turn Off
Detection
12k
VCC
Shoot-Through
Protection
12k
GND
LGATE
PHASE
UGATE
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9612A/B-03 June 2012
RT9612A/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 (VCC + 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
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.
DS9612A/B-03 June 2012
www.richtek.com
5
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