®
RT9627A
High Voltage Synchronous Rectified Dual-Channel Buck
MOSFET Driver for Notebook Computer
General Description
The RT9627A is a high frequency, dual-channel driver
specifically designed to drive two power N-MOSFETs in
each channel of a synchronous-rectified Buck converter
topology. It is especially suited for mobile computing
applications that require high efficiency and excellent
thermal performance. This driver, combined with Richtek's
series of multi-phase Buck PWM controllers, provides a
complete core voltage regulator solution for advanced
microprocessors.
The drivers are capable of driving a 3nF load with fast
rising/falling time and fast propagation delay. This device
implements bootstrapping on the upper gates with only a
single external capacitor. This reduces implementation
complexity and allows the use of higher performance, cost
effective, N-MOSFETs. Adaptive shoot through protection
is integrated to prevent both MOSFETs from conducting
simultaneously.
Features
Dual-Channel Driver
Each Channel Drives Two N-MOSFETs
Adaptive Shoot-Through Protection
0.5Ω On-Resistance, 4A Sink Current Capability
Ω
Supports High Switching Frequency
Tri-State PWM Input for Power Stage Shutdown
Output Disable Function
Integrated Boost Switch
Low Bias Supply Current
VCC POR Feature Integrated
RoHS Compliant and Halogen Free
Applications
Core Voltage Supplies for Intel
®
/ AMD
®
Mobile
Microprocessors
High Frequency Low Profile DC/DC Converters
High Current Low Output Voltage DC/DC Converters
High Input Voltage DC/DC Converters
Simplified Application Circuit
R1
C1
RT9627A
VCC
UGATE1
BOOT1
PHASE1
Enable
EN
LGATE1
R2
V
IN
C2
Q
UG1
L2
V
CORE
Q
LG1
C3
R5
V
IN
UGATE2
PWM2
PWM2
BOOT2
PHASE2
Q
LG2
GND
LGATE2
C16
R8
R5
C15
Q
UG2
L3
C
OUT
C
IN
V
CC
PWM1
PWM1
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9627A-00 November 2012
www.richtek.com
1
RT9627A
Ordering Information
RT9627A
Package Type
QW : WDFN-12L 3x3 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
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.
WDFN-12L 3x3
UGATE1
BOOT1
PWM1
PWM2
EN
BOOT2
Pin Configurations
(TOP VIEW)
1
2
3
4
5
6
12
11
10
9
8
7
13
PHASE1
LGATE1
VCC
LGATE2
PHASE2
UGATE2
Marking Information
0H= : Product Code
0H=YM
DNN
YMDNN : Date Code
Functional Pin Description
Pin No.
1, 7
2, 6
Pin Name
Pin Function
UGATE1, High Side Gate Drive Outputs. Connect to the Gates of high side power
UGATE2
N-MOSFETs.
BOOT1,
BOOT2
PWM1,
PWM2
EN
PHASE2,
PHASE1
LGATE2,
LGATE1
VCC
Bootstrap Supply for High Side Gate Drives. Connect the bootstrap capacitors
between these pins and the PHASEx pins. The bootstrap capacitors provide the
charge to turn on the high side MOSFETs.
Control Inputs for Drivers. The PWM signal can enter three distinct states during
operation. Connect these pins to the PWM outputs of the controller.
Enable Control Input. When pulling low, both UGATEx and LGATEx are driven low
and the normal operation is disabled.
Switch Nodes. Connect these pins to the Sources of the high side MOSFETs and
the Drains of the low side MOSFETs. These pins provide return paths for the high
side gate drivers.
Low Side Gate Drive Outputs. Connect to the Gates of the low side power
N-MOSFETs.
Supply Voltage Input. Connect this pin to a 5V bias supply. Place a high quality
bypass capacitor from this pin to GND.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
3, 4
5
8, 12
9, 11
10
13 (Exposed Pad) GND
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9627A-00 November 2012
GND
RT9627A
Function Block Diagram
VCC
POR
EN
Control
Logic
Shoot-Through
Protection
VCC
LGATE1
GND
BOOT2
UGATE1
PHASE1
BOOT1
VCC
R
PWM1
R
Tri-State
Detect
VCC
R
PWM2
R
Tri-State
Detect
Control
Logic
Shoot-Through
Protection
VCC
UGATE2
PHASE2
LGATE2
Operation
POR (Power On Reset)
POR block detects the voltage at the VCC pin. When the
VCC pin voltage is higher than POR rising threshold, the
POR pin output voltage (POR output) is high. POR output
is low when VCC is not higher than POR rising threshold.
When the POR pin voltage is high, UGATEx and LGATEx
can be controlled by PWMx input voltage. If the POR pin
voltage is low, both UGATEx and LGATEx will be pulled
to low.
Tri-State Detect
When both POR output and ENx pin voltages are high,
UGATEx and LGATEx can be controlled by PWMx input.
There are three PWMx input modes which are high, low,
and shutdown state. If PWMx input is within the shutdown
window, both UGATEx and LGATEx outputs are low. When
PWMx input is higher than its rising threshold, UGATEx
is high and LGATEx is low. When PWMx input is lower
than its falling threshold, UGATEx is low and LGATEx is
high.
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
Control Logic
Control logic block detects whether high side MOSFET
is turned off by monitoring (UGATEx
−
PHASEx) voltages
below 1.1V or phase voltage below 2V. To prevent the
overlap of the gate drives during the UGATEx pull low and
the LGATEx pull high, low side MOSFET can be turned
on only after high side MOSFET is effectively turned off.
Shoot-Through Protection
Shoot-through protection block implements the dead-time
when both high side and low side MOSFETs are turned
off. With shoot-through protection block, high side and
low side MOSFETs are never turned on simultaneously.
Thus, shoot-through between high side and low side
MOSFETs is prevented.
is a registered trademark of Richtek Technology Corporation.
DS9627A-00 November 2012
www.richtek.com
3
RT9627A
Absolute Maximum Ratings
(Note 1)
−0.3V
to 6V
−0.3V
to 6V
−0.3V
to 32V
−8V
to 38V
−0.3V
to 6V
Supply Voltage, VCC -----------------------------------------------------------------------------------------------------
BOOTx to PHASEx -------------------------------------------------------------------------------------------------------
PHASEx to GND
DC -----------------------------------------------------------------------------------------------------------------------------
< 20ns -----------------------------------------------------------------------------------------------------------------------
UGATEx to PHASEx
DC -----------------------------------------------------------------------------------------------------------------------------
< 20ns -----------------------------------------------------------------------------------------------------------------------
−5V
to 7.5V
LGATEx to GND
DC -----------------------------------------------------------------------------------------------------------------------------
−0.3V
to 6V
< 20ns -----------------------------------------------------------------------------------------------------------------------
−2.5V
to 7.5V
PWMx, EN to GND ------------------------------------------------------------------------------------------------------
−
0.3V to 6V
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-12L 3x3 ------------------------------------------------------------------------------------------------------------- 3.28W
Package Thermal Resistance (Note 2)
WDFN-12L 3x3,
θ
JA
------------------------------------------------------------------------------------------------------- 30.5°C/W
WDFN-12L 3x3,
θ
JC
-------------------------------------------------------------------------------------------------------
Junction Temperature -----------------------------------------------------------------------------------------------------
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------
Storage Temperature Range --------------------------------------------------------------------------------------------
ESD Susceptibility (Note 3)
HBM (Human Body Model) ----------------------------------------------------------------------------------------------
7.5°C/W
150°C
260°C
−65°C
to 150°C
2kV
Recommended Operating Conditions
(Note 4)
4.5V to 26V
4.5V to 5.5V
−40°C
to 85°C
−40°C
to 125°C
Input Voltage, VIN ---------------------------------------------------------------------------------------------------------
Supply Voltage, VCC -----------------------------------------------------------------------------------------------------
Ambient Temperature Range --------------------------------------------------------------------------------------------
Junction Temperature Range --------------------------------------------------------------------------------------------
Electrical Characteristics
(V
CC
= 5V, T
A
= 25°C, unless otherwise specified)
Parameter
VCC Supply Current
Quiescent Current
Shutdown Current
VCC Power On Reset
(POR)
Internal BOOT Switch
Internal Boot Switch On
Resistance
Symbol
I
Q
I
SHDN
V
PORH
V
PORL
V
PORHYS
Test Conditions
PW M Pin Floating, V
EN
= 3.3V
V
EN
= 0V, PWM = 0V
VCC POR Rising
VCC POR Falling
Hysteresis
Min
--
--
--
3.4
--
Typ
120
0
3.85
3.65
200
Max
--
5
4.1
--
--
Unit
μA
μA
V
V
mV
Ω
R
BOOT
VCC to BOOT, 10mA
--
--
80
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9627A-00 November 2012
RT9627A
Parameter
PWMx Input
Input Current
PWMx Tri-State Rising Threshold
PWMx Tri-State Falling Threshold
Tri-State Shutdown Hold-off Time
EN Input
EN Input Voltage
Switching Time
UGATEx Rise Time
UGATEx Fall Time
LGATEx Rise Time
LGATEx Fall Time
UGATEx Turn-Off Propagation
Delay
LGATEx Turn-Off Propagation
Delay
UGATEx Turn-On Propagation
Delay
LGATEx Turn-On Propagation
Delay
UGATEx/LGATEx Tri-State
Propagation Delay
Output
UGATEx Driver Source Current
UGATEx Driver Sink Resistance
UGATEx Driver Sink Current
LGATEx Driver Source Current
LGATEx Driver Sink Resistance
LGATEx Driver Sink Current
t
UGATEr
t
UGATEf
t
LGATEr
t
LGATEf
t
PDLU
t
PDLL
t
PDHU
t
PDHL
t
PTS
3nF load
3nF load
3nF load
3nF load
Outputs Unloaded
Outputs Unloaded
Outputs Unloaded
Outputs Unloaded
Outputs Unloaded
--
--
--
--
--
--
--
--
--
8
8
8
4
35
35
20
20
35
--
--
--
--
--
--
--
--
--
ns
ns
ns
ns
ns
ns
ns
ns
ns
Ω
A
Ω
A
Ω
A
Ω
A
Logic-High
Logic-Low
V
ENH
V
ENL
2
--
--
--
--
0.5
V
I
PWM
V
PWMH
V
PWML
t
SHD_Tri
V
PWM
= 5V
V
PWM
= 0V
--
--
3.5
0.7
100
174
−174
3.8
1
175
--
--
4.1
1.3
250
μA
V
V
ns
Symbol
Test Conditions
Min
Typ
Max
Unit
UGATEx Driver Source Resistance R
UGATEsr
I
UGATEsr
R
UGATEsk
I
UGATEsk
I
LGATEsr
R
LGATEsk
I
LGATEsk
100mA Source Current
V
UGATE
−
V
PHASE
= 2.5V
100mA Sink Current
V
UGATE
−
V
PHASE
= 2.5V
100mA Source Current
V
LGATE
= 2.5V
100mA Sink Current
V
LGATE
= 2.5V
--
--
--
--
--
--
--
--
1
2
1
2
1
2
0.5
4
--
--
--
--
--
--
--
--
LGATEx Driver Source Resistance R
LGATEsr
Note 1.
Stresses beyond those listed
“Absolute
Maximum Ratings” may cause permanent damage to the device. These are
stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may
affect device reliability.
Note 2.
θ
JA
is measured at T
A
= 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7.
θ
JC
is
measured at the exposed pad of the package.
Note 3.
Devices are ESD sensitive. Handling precaution recommended. The human body mode is a 100pF capacitor is
charged through a 1.5kΩ resistor into each pin.
Note 4.
The device is not guaranteed to function outside its operating conditions.
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9627A-00 November 2012
www.richtek.com
5
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