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RC5055
PRODUCT SPECIFICATION
2
Pin Assignments
Pin Definitions
Pin Number Pin Name
1
Pin Function Description
This pin is connected to the converter’s output voltage. The PGOOD and OVP
comparator circuits use this signal to report output voltage status and for overvoltage
protection.
Connect a resistor (ROCSET) from this pin to the drain of the upper MOSFET. An
internal 200μA current source (Iocs) and the upper MOSFET R
DS(ON)
set the converter
peak over-current trip point:
I
R
DS ON
VSEN
2
OCSET
3
SS
Soft Start. A capacitor from this point to ground together with an internal 10μA will
cause the output duty cycle to increase slowly
Linear Regulator Error Amplifier Output.
Linear Regulator Error Amplifier Inverting Input. When FB1 and GATE1 are tied
together the Output Voltage = Vref
DAC inputs. Used to adjust the output voltage to the voltage required by the processor.
Input for fixed linear regulator
2.5V fixed output from fixed linear regulator
PWM Loop Error Amplifier output.
PWM Loop Voltage Feedback. Inverting input of Error Amplifier.
Analog Ground.
Power good. This pin is pulled low when any of the regulator’s output is not within the
spec.
Connect the PHASE pin to the upper MOSFET source. This pin is used to monitor the
voltage drop across the MOSFET for over-current protection. This pin also provides the
return path for the upper gate drive.
Upper MOSFET gate driver
Upper MOSFET bootstrap.
12V bias supply.
Low MOSFET gate driver.
Power ground.
Over-voltage Protection. This pin drives an external SCR.
Oscillator switching frequency adjust according to the following equations:
6
]
R
T
Kohm
5
]
R
T
Kohm
4
5
GATE1
FB1
6-10
11
12
13
14
15
16
VID0-4
LVIN
LVOUT
COMP
FB
GND
PGOOD
17
PHASE
18
19
20
21
22
23
24
UGATE
BOOT
VCC
LGATE
PGND
OVP
RT
1
2
3
4
5
6
8
7
RT
OVP
PGND
VCC
BOOT
UGATE
LGATE
PHASE
PGOOD
GND
24
23
22
21
20
19
17
9
16
65-5055-02
18
VSEN
OCSET
SS
VID0
VID1
VID2
VID3
VID4
LVIN
COMP
FB
10
15
11
14
LVOUT
FB1
12
13
GATE1
I
PEAK
OCSET
)
------------------R
=
F
S
200kHz
-------------------------KHz x Kohm
[
]
+
=
R
T
to GND
(
)
F
S
200kHz
-------------------KHz x Kohm
[
]
–
=
R
T
to 12V
(
)