Document
RT9619/A
Synchronous-Rectified Buck MOSFET Drivers
General Description
The RT9619/A is a high frequency, dual MOSFET driver specifically designed to drive two power N-Channel MOSFETs in a synchronous-rectified buck converter topology. This driver combined with Richtek's series of Multi-Phase Buck PWM controller form a complete corevoltage regulator solution for advanced micro-processors. www.DataSheet4U.com The RT9619/A drives both the lower/upper gate in a synchronous-rectifier bridge with 12V. This drive-voltage flexibility provides the advantage of optimizing applications involving trade-offs between switching losses and conduction losses. RT9619A has longer UGATE/LGATE deadtime which can drive the MOSFETs with large gate RC value, avoiding the shoot-through phenomenon. RT9619 is targeted to drive low gate RC MOSFETs and performs better efficiency. The output drivers in the RT9619/A can efficiently switch power MOSFETs at frequency up to 500kHz. Switching frequency above 500kHz has to take into account the thermal dissipation of SOP-8 package. RT9619/A is capable to drive a 3nF load with a 30ns rise time. RT9619/A implements bootstrapping on the upper gate with an external capacitor and an embedded diode. This reduces implementation complexity and allows the use of higher performance, cost effective N-Channel MOSFETs. Adaptive shoot-through protection is integrated to prevent both MOSFETs from conducting simultaneously.
Features
z z z z z z z z z z
Drives Two N-Channel MOSFETs Adaptive Shoot-Through Protection Embedded Boot Strapped Diode Supports High Switching Frequency Fast Output Rise Time Small SOP-8 Package Tri-State Input for Bridge Shutdown Supply Under Voltage Protection Upper MOSFET Direct Shorted Protection RoHS Compliant and 100% Lead (Pb)-Free
Applications
z z z
Core Voltage Supplies for Desktop, Motherboard CPU High Frequency Low Profile DC-DC Converters High Current Low Voltage DC-DC Converters
Ordering Information
RT9619/A Package Type S : SOP-8 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) Long Dead Time Short Dead Time
Note : RichTek Pb-free and Green products are : `RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. `Suitable for use in SnPb or Pb-free soldering processes. `100% matte tin (Sn) plating.
Pin Configurations
(TOP VIEW)
BOOT PWM NC VCC 2 3 4 8 7 6 5 UGATE PHASE PGND LGATE
SOP-8
DS9619/A-04 March 2007
www.richtek.com 1
www.DataSheet4U.com
www.richtek.com 2
L1 2.2uH VIN C9 10uF C2 1uF C10 1000uF C11 1000uF C12 1000uF C13 10uF C14 10uF
D1
RT9619/A
Typical Application Circuit
ATX_12V
C8 10uF
R2 1 1 BOOT R3 2.2 Q1 L2 1uH
+
ATX_12V UGATE C1 1uF RT9619/A 3 NC PWM LGATE PGND 6 5 R4 0 PWM 2 Q2 PHASE 7 R5 2.2 C3 3.3nF
R1 10 4 VCC 8
VCORE
+ + +
C4 2200uF
C5 2200uF
C6 10uF
C7 10uF
DS9619/A-04 March 2007
RT9619/A
Functional Pin Description
Pin No. 1 2 3 4 5 6
www.DataSheet4U.com
Pin Name BOOT PWM NC VCC LGATE PGND PHASE UGATE
Pin Function Floating bootstrap supply pin for upper gate drive. Input PWM signal for controlling the driver. No Connection Pin. +12V Supply Voltage. Lower Gate Drive Output. Connected to gate of low-side power N-Channel MOSFET. Common Ground. Connected this pin to the source of the high-side MOSFET and the drain of the low-side MOSFET. Upper Gate Drive Output. Connected to gate of high-side power N-Channel MOSFET.
7 8
Function Block Diagram
VCC Internal 5V POR R PWM R Turn off Detect VCC Shoot-Through Protection LGATE PGND PHASE Tri-State Detect Shoot-Through Protection BOOT UGATE
Timing Diagram
PWM LGATE
tpdlLGATE 90% 2V tpdlUGATE
2V
90% 2V UGATE tpdhUGATE tpdhLGATE 2V
DS9619/A-04 March 2007
www.richtek.com 3
RT9619/A
Absolute Maximum Ratings
z z
(Note 1) −0.3V to 15V −0.3V to 15V −0.3V to VCC + 15V −0.3V to 42V −5V to 15V −10V to 30V GND − 0.3V to VCC + 0.3V −2V to VCC + 0.3V VPHASE − 0.3V to VBOOT + 0.3V VPHASE − 2V to VBOOT + 0.3V GND − 0.3V to 7V 0.625W 160°C/W 260°C −40°C to 150°C 2kV 200V
Supply Voltage, VCC ------------------------------------------------------------------------------------BOOT to PHASE ----------------------------------------------------------------------------------------z BOOT to GND DC -----------------------------------------------------------------------------------------------------------< 200ns ----------------------------------------------------------------------------------------------------z PHASE to GND DC -----------------------------------------------------------------------------------------------------------< 200ns ----------------------------------------------------------------------------------------------------z LGATE www.DataSheet4U.com DC -----------------------------------------------------------------------------------------------------------< 200ns ----------------------------------------------------------------------------------------------------z UGATE -----------------------.