Converter. RT6220DH Datasheet

RT6220DH Datasheet PDF

Part RT6220DH
Description Synchronous Buck Converter
Feature RT6220DH; ® RT6220DH 6A, 23V, 500kHz, ACOTTM Synchronous Buck Converter General Description The RT6220DH is .
Manufacture Richtek
Datasheet
Download RT6220DH Datasheet




RT6220DH
®
RT6220DH
6A, 23V, 500kHz, ACOTTM Synchronous Buck Converter
General Description
The RT6220DH is a synchronous Buck converter with
Advanced Constant On-Time (ACOTTM) mode control,
which provides a very fast transient response with no
external compensators. The RT6220DH operates from
4.5V to 23V input voltage, provides complete protection
functions including Over Current Protection (OCP), Under
Voltage Protection (UVP) and Over Voltage Protection
(OVP). This IC also provides a 1.5ms internal soft-start
function and an open-drain power good indicator.
Ordering Information
RT6220DH
Package Type
QUF : UQFN-16L 3x3 (FC) (U-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.
Features
4.5V to 23V Input Voltage Range
Adjustable from 0.6V to 5V Output Range
500kHz Switching Frequency
ACOTTM Mode Performs Fast Transient Response
Integrated MOSFETs
31mΩ of High-Side MOSFET
20mΩ of Low-Side MOSFET
Supports MLCC Output Capacitors
Internal Soft-Start (1.5ms typ)
Built-in OVP/UVP/OCP
Power Good Indicator
Thermal Shutdown
Applications
Laptop Computers
Tablet PCs
Networking Systems
Servers
Personal Video Recorders
Flat Panel Television and Monitors
Distributed Power Systems
Simplified Application Circuit
VIN
Chip Enable
CIN
CEN
VSYS
RBYP
CBYP
VIN BOOT
RT6220DH
EN
VBYP
SW
VOUT
FB
PGND
AGND
PGOOD
VCC
CB
L
RPGOOD
VCC
CVCC
VOUT
R1 COUT
R2
Copyright ©2017 Richtek Technology Corporation. All rights reserved.
DS6220DH-00 September 2017
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1



RT6220DH
RT6220DH
Pin Configuration
(TOP VIEW)
14 13 12 11 10
VIN 1
15 9 SW
PGND 2
SW
16
SW
8 SW
34567
Marking Information
P0= : Product Code
P0=YM
DNN
YMDNN : Date Code
UQFN-16L 3x3 (FC)
Functional Pin Description
Pin No. Pin Name
Pin Function
1 VIN
Power input connect to high-side MOSFET drain.
2 PGND Power ground.
Switch over input supply voltage for VCC. A low pass filter should be connected to
3
VBYP
AGND, if VBYP is applied. If VBYP is not used, then connect to AGND. Do not connect
to VCC pin.
4 PGOOD Open-drain power good indicator output.
5, 6, 14 AGND Analog ground.
7 VOUT Output voltage sense input. An internal discharging circuit is connected to this pin.
8, 9, 15, 16 SW
Switch node.
Bootstrap supply for high-side gate driver. A capacitor is needed to drive the power
10 BOOT switch's gate above the supply voltage. It is connected between the SW and BOOT
pins to form a floating supply across the power switch driver.
11
VCC
5V linear regulator output for internal control circuit. Bypass VCC to AGND with a 2.2F
capacitor. VCC can only supply internal circuits. Do not connect to external loads.
12 FB
Feedback voltage input.
13 EN
Enable control input. Do not leave this pin floating. The slew rate of EN is
recommended to be slower than 4.8V/s.
Copyright ©2017 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
is a registered trademark of Richtek Technology Corporation.
DS6220DH-00 September 2017



RT6220DH
Functional Block Diagram
VCC
VBYP
RT6220DH
FB
EN
VOUT
Soft-Start
POR &
Reference
VCC
Switch-Over
VREF
+
+
VFB -
On-Time
One shot
Min off Time
VCC
Gate
Control
Logic
VCC
VIN
125% x VREF
- OVP
+
91.5% x VREF
-
+
SW
VOC
POK
58% x VREF
OCP
+
-
Fault
Logic
+ UVP
-
VCC
VCC
Regulator
BOOT
SW
PGND
PGOOD
AGND
VIN
Operation
Overall
The RT6220DH is a synchronous step-down converter with
advanced constant on-time control mode. Using the
ACOTTM control mode can reduce the output capacitance
and provide fast transient response. It can minimize the
component size without additional external compensation
network.
Internal VCC Regulator
The regulator provides 5V power to supply the internal
control circuit. Connecting a 2.2μF ceramic capacitor for
decoupling and stability is required.
Soft-Start
In order to prevent the converter output voltage from
overshooting during the startup period, the soft-start
function is necessary. The soft-start time is internal setting
and the duration is around 1.5ms.
OCP
The inductor valley current is monitored cycle-by-cycle
via the internal switches, preventing an on-time until the
current drops below the current limit.
Power Good
After soft-start is finished, the power good output goes
high. The PGOOD pin is an open-drain output.
VCC Switch-Over
The internal regulator output will switch over to VBYP if
VBYP level is higher than 4.6V.
Power Off
There is an internal discharging circuit to discharge the
residual charge of output capacitor when converter is power
off.
Copyright ©2017 Richtek Technology Corporation. All rights reserved.
DS6220DH-00 September 2017
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
3







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