RT6228A/B/C
Functional Pin Description
Pin No.
Pin Name
Pin Function
Boot-strap pin. Supply high-side gate driver. A 0.1F ceramic capacitor and
at least 10 RBOOT are connected between this pin and LX pin.
1
BOOT
2,3
4
LX
Inductor pin. Connect this pin to the switching node of inductor.
Power ground.
PGND
VIN
5
Input pin. Decouple this pin to GND pin with at least 10F ceramic cap.
Enable control. Pull this pin high to turn on the Buck. Do not leave this pin
floating. EN pin will also be used to set USM mode, when EN pin voltage is
between 2.3V and 23V, it will enter USM mode, if EN pin voltage is between
0.8V and 1.7V, then it is normal mode.
EN
(RT6228A)
Enable control. Pull this pin high to turn on the Buck. Do not leave this pin
floating. EN pin will also be used to set USM mode, when EN pin voltage is
between 2.3V and 23V, it will enter USM mode, if EN pin voltage is between
0.8V and 1.7V, then it is normal mode.
EN
(RT6228B)
6
Enable control. Pull this pin high to turn on the Buck and CLK. Do not leave
this pin floating. EN pin will also be used to set USM mode, when EN pin
voltage is between 2.3V and 23V, it will enter USM mode, if EN pin voltage is
between 0.8V and 1.7V, then it is normal mode.
EN
(RT6228C)
Power good Indicator. Open drain output when the output voltage is higher
than 90% of regulation point.
7
8
9
PGOOD
AGND
VCC
Analog ground.
5V linear regulator output for internal control circuit. A capacitor (typical 1F)
should be connected to AGND. Don’t connect to external Load.
FB
(RT6228A)
Output feedback pin. Connect this pin to the center point of the output
resistor divider to program the output voltage.
VOUT
(RT6228B)
10
11
12
Output pin. Connect to the output of DC-DC regulator.
VOUT
(RT6228C)
Output pin. Connect to the output of DC-DC regulator. The pin also provide
the bypass input for 3.3V LDO.
Bypass input for the internal LDO. BYP is externally connected to the output
of switching regulator. When the BYP voltage rises above the bypass switch
turn-on threshold, the LDO regulator shuts down and the VCC pin is
connected to the BYP pin through an internal switch.
BYP
(RT6228A)
Bypass input for the internal LDO. BYP is externally connected to the output
of switching regulator. When the BYP voltage rises above the bypass switch
turn-on threshold, the LDO regulator shuts down and the VCC pin is
connected to the BYP pin through an internal switch.
BYP
(RT6228B)
LDO
(RT6228C)
Internal 3.3V LDO output. Bypass a capacitor to GND. This pin is also
capable sourcing 100mA current for external load.
ILMT
(RT6228A)
Current limit setting pin. The current limit is set to 8A, 10A or 12A when this
pin is pull low, floating or pull high respectively.
ILMT
(RT6228B)
Current limit setting pin. The current limit is set to 8A, 10A or 12A when this
pin is pull low, floating or pull high respectively.
CLK
(RT6228C)
300kHz CLK output to drive the external charge pump.
Copyright 2018 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS6228A/B/C-02 September 2018
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
