RT6278A/B
Pin Configuration
Marking Information
RT6278AHGQUF
(TOP VIEW)
M8= : Product Code
YMDNN : Date Code
M8=YM
DNN
12 11 10
1
9
8
7
6
BOOT
LX
EN
5
VIN
2
3
RT6278BHGQUF
4
PGND
M7= : Product Code
YMDNN : Date Code
LX
M7=YM
DNN
UQFN-12HL 3x3
Functional Pin Description
Pin No.
Pin Name
Pin Function
Boot-strap pin. Supply high-side gate driver. Decouple this pin to LX pin with
0.1F ceramic cap.
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 for RT6278A, 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.
6
EN
Power good indicator. Open drain output when the output voltage is within
90% to 120% of regulation point.
7
8
9
PGOOD
AGND
VCC
Analog ground. Connect AGND to a clean inner GND point with separate
trace.
5V linear regulator output for internal control circuit. A capacitor (typical 1F)
should be connected to PGND. Don’t connect to external Load.
Output feedback pin. Connect this pin to the center point of the output
resistor divider to program the output voltage.
10
11
12
FB
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. But when BYP pin is
not used, it should be connected to ground.
BYP
ILMT
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.
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is a registered trademark of Richtek Technology Corporation.
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2
DS6278A/B-01 May 2018
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
