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RT9619/A

Synchronous-Rectified Buck MOSFET Drivers
General Description Features
The RT9619/A is a high frequency, dual MOSFET driver Drives Two N-Channel MOSFETs
specifically designed to drive two power N-Channel Adaptive Shoot-Through Protection
MOSFETs in a synchronous-rectified buck converter Embedded Boot Strapped Diode
topology. This driver combined with Richtek's series of Supports High Switching Frequency
Multi-Phase Buck PWM controller form a complete core- Fast Output Rise Time
voltage regulator solution for advanced micro-processors. Small SOP-8 Package
Tri-State Input for Bridge Shutdown
The RT9619/A drives both the lower/upper gate in a
Supply Under Voltage Protection
synchronous-rectifier bridge with 12V. This drive-voltage
Upper MOSFET Direct Shorted Protection
flexibility provides the advantage of optimizing applications
RoHS Compliant and 100% Lead (Pb)-Free
involving trade-offs between switching losses and
conduction losses.
Applications
RT9619A has longer UGATE/LGATE deadtime which can
Core Voltage Supplies for Desktop, Motherboard CPU
drive the MOSFETs with large gate RC value, avoiding the
High Frequency Low Profile DC-DC Converters
shoot-through phenomenon. RT9619 is targeted to drive
High Current Low Voltage DC-DC Converters
low gate RC MOSFETs and performs better efficiency.
The output drivers in the RT9619/A can efficiently switch Ordering Information
power MOSFETs at frequency up to 500kHz. Switching RT9619/A
frequency above 500kHz has to take into account the
Package Type
thermal dissipation of SOP-8 package. RT9619/A is S : SOP-8
capable to drive a 3nF load with a 30ns rise time. Operating Temperature Range
RT9619/A implements bootstrapping on the upper gate with P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
an external capacitor and an embedded diode. This reduces cial Standard)
implementation complexity and allows the use of higher
Long Dead Time
performance, cost effective N-Channel MOSFETs. Adaptive Short Dead Time
shoot-through protection is integrated to prevent both
Note :
MOSFETs from conducting simultaneously.
RichTek Pb-free and Green products are :
RoHS compliant and compatible with the current require-
Pin Configurations ments of IPC/JEDEC J-STD-020.

(TOP VIEW) Suitable for use in SnPb or Pb-free soldering processes.
100% matte tin (Sn) plating.
BOOT 8 UGATE
PWM 2 7 PHASE
NC 3 6 PGND
VCC 4 5 LGATE

SOP-8




DS9619/A-04 March 2007 www.richtek.com
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www.richtek.com
RT9619/A




L1
2.2uH
ATX_12V VIN
Typical Application Circuit




C8 C9 C10 C11 C12 C13 C14
10uF 10uF 1000uF 1000uF 1000uF 10uF 10uF

C2
R2 1uF
D1 1

1
R1 BOOT R3
10 8 2.2
ATX_12V 4 VCC
UGATE Q1
C1
1uF L2
RT9619/A
7 1uH
3 PHASE VCORE
+
+
+
+




NC
R4 R5
2 5 0 2.2 C4 C5 C6 C7
PWM PWM LGATE Q2 2200uF 2200uF 10uF 10uF
C3
PGND 3.3nF
6




DS9619/A-04 March 2007
RT9619/A
Functional Pin Description
Pin No. Pin Name Pin Function
1 BOOT Floating bootstrap supply pin for upper gate drive.
2 PWM Input PWM signal for controlling the driver.
3 NC No Connection Pin.
4 VCC +12V Supply Voltage.
5 LGATE Lower Gate Drive Output. Connected to gate of low-side power N-Channel MOSFET.
6 PGND Common Ground.
Connected this pin to the source of the high-side MOSFET and the drain of the low-side
7 PHASE
MOSFET.
8 UGATE Upper Gate Drive Output. Connected to gate of high-side power N-Channel MOSFET.



Function Block Diagram
VCC


Internal
5V
POR
R
BOOT
Tri-State
PWM Detect Shoot-Through
UGATE
Protection
R


Turn off Detect PHASE

VCC

Shoot-Through
Protection LGATE
PGND




Timing Diagram


PWM
tpdlLGATE

LGATE 90%
tpdlUGATE
2V 2V



90%
2V 2V
UGATE

tpdhUGATE tpdhLGATE




DS9619/A-04 March 2007 www.richtek.com
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RT9619/A
Absolute Maximum Ratings (Note 1)
Supply Voltage, VCC ------------------------------------------------------------------------------------- -0.3V to 15V
BOOT to PHASE ----------------------------------------------------------------------------------------- -0.3V to 15V
BOOT to GND
DC ------------------------------------------------------------------------------------------------------------ -0.3V to VCC + 15V
< 200ns ----------------------------------------------------------------------------------------------------- -0.3V to 42V
PHASE to GND
DC ------------------------------------------------------------------------------------------------------------ -5V to 15V
< 200ns ----------------------------------------------------------------------------------------------------- -10V to 30V
LGATE
DC ------------------------------------------------------------------------------------------------------------ GND - 0.3V to VCC + 0.3V
< 200ns ----------------------------------------------------------------------------------------------------- -2V to VCC + 0.3V
UGATE ------------------------------------------------------------------------------------------------------ VPHASE - 0.3V to VBOOT + 0.3V
< 200ns ----------------------------------------------------------------------------------------------------- VPHASE - 2V to VBOOT + 0.3V
PWM Input Voltage -------------------------------------------------------------------------------------- GND - 0.3V to 7V
Power Dissipation, PD @ TA = 25