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RT6236A/B
6A, 18V, 650kHz, ACOTTM Synchronous Step-Down Converter
General Description
The RT6236A/B is a high-performance 650kHz, 6A stepdown regulator with internal power switches and synchronous rectifiers. It features quick transient response using its Advanced Constant On-Time (ACOTTM) control architecture that provides stable operation with small ceramic output capacitors and without complicated external compensation, among other benefits. The input voltage range is from 4.5V to 18V and the output is adjustable from 0.7V to 8V. The proprietary ACOTTM control improves upon other fast response constant on-time architectures, achieving nearly constant switching frequency over line, load, and output voltage ranges. Since there is no internal clock, response to transients is nearly instantaneous and inductor current can ramp quickly to maintain output regulation without large bulk output capacitance. The RT6236A/B is stable with and optimized for ceramic output capacitors. With internal 51mΩ switches and 18mΩ synchronous rectifiers, the RT6236A/B displays excellent efficiency and good behavior across a range of applications, especially for low output voltages and low duty cycles. Cycle-by-cycle current limit provides protection against shorted outputs, input under-voltage lock-out, externally-adjustable soft-start, output under- and over-voltage protection, and thermal shutdown provide safe and smooth operation in all operating conditions. The RT6236A/B is available in the UQFN-13JL 2x3 (FC) package, with exposed thermal pad.
Features
Fast Transient Response Advanced Constant On-Time (ACOTTM) Control 4.5V to 18V Input Voltage Range Adjustable Output Voltage from 0.7V to 8V 6A Output Current 51mΩ Internal High-Side N-MOSFET and 18mΩ
Internal Low-Side N-MOSFET Steady 650kHz Switching Frequency Up to 95% Efficiency Optimized for All Ceramic Capacitors Externally-Adjustable, Pre-biased Compatible Soft-
Start Cycle-by-Cycle Current Limit Input Under-Voltage Lockout Output Over- and Under-Voltage Protection Power Good Output Externally-Adjustable, Pre-biased Compatible Soft-
Start Thermal Shutdown
Applications
Industrial and Commercial Low Power Systems Computer Peripherals LCD Monitors and TVs Green Electronics/Appliances Point of Load Regulation for High-Performance DSPs,
FPGAs, and ASICs
Simplified Application Circuit
VIN CIN
VPVCC
RPG
Enable
CSS
RT6236A/B VIN SW
BOOT PGOOD EN FB SS PVCC
GND
L
CBOOT CFF R1
COUT
VOUT
VPVCC CPVCC
R2
Copyright ©2018 Richtek Technology Corporation. All rights reserved. DS6236A/B-03 January 2018
is a registered trademark of Richtek Technology Corporation.
www.richtek.com 1
RT6236A/B
Ordering Information
RT6236A/B
Package Type QUF : UQFN-13JL 2x3 (U-Type) (FC) Lead Plating System G : Green (Halogen Free and Pb Free)
H : Hiccup Mode UVP L : Latched OVP & UVP A : PSM B : PWM
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.
Pin Configuration
(TOP VIEW)
GND SW BOOT
13 12 11
GND 1
10 VIN
EN 2
9 VIN
FB 3
8 PGOOD
NC 4
7 NC
56
SS PVCC
UQFN-13JL 2x3 (FC)
Marking Information
RT6236AHGQUF
0Z : Product Code
0ZW
W : Date Code
RT6236BHGQUF
0X : Product Code
0XW
W : Date Code
RT6236ALGQUF
0Y : Product Code
0YW
W : Date Code
RT6236BLGQUF
0W : Product Code
0WW
W : Date Code
Functional Pin Description
Pin No.
Pin Name
Pin Function
1, 13
GND
Ground.
2 EN Enable control input.
3 FB
Converter feedback input. Connect to output voltage feedback resistor divider.
4, 7 NC
No internal connection.
5 SS Soft-start control. A external capacitor should be connected to GND.
6
PVCC
5V power supply output. A capacitor (typical 1F) should be connected to GND.
8 PGOOD Open drain power good output.
9, 10
VIN
Power input and connected to high-side MOSFET drain.
Bootstrap. This capacitor is needed to drive the power switch's gate above the
11
BOOT
supply voltage. It is connected between SW and BOOT pins to form a floating
supply across the power switch driver. A 0.1F capacitor is recommended for use.
12 SW
Switch output.
Copyright ©2018 Richtek Technology Corporation. All rights reserved.
www.richtek.com 2
is a registered trademark of Richtek Technology Corporation.
DS6236A/B-03 January 2018
Functional Block Diagram
PVCC
BOOT
VIN Reg
VIBIAS
PVCC VREF
Min. Off
PVCC
UGATE
OC
Control
Driver
LGATE
UV & OV
GND SW
PVCC SW
Ripple Gen.
6µA
SS FB
+ -
Comparator
0.9 VREF FB
+ -
VIN Comparator
SW On-Time
EN
RT6236A/B
VIN SW GND PGOOD
Detailed Description
The RT6236A/B is a high-performance 650kHz 6A stepdown regulators with internal power switches and synchronous rectifiers. It features an Advanced Constant On-Time (ACOTTM) control architecture that provides stable operation with ceramic output capac.