FAN6754B Fairchild Semiconductor, FAN6754B Datasheet - Page 3

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FAN6754B

Manufacturer Part Number
FAN6754B
Description
The highly integrated FAN6754A PWM controller provides several features to enhance the performance of flyback converters
Manufacturer
Fairchild Semiconductor
Datasheet
© 2011 Fairchild Semiconductor Corporation
FAN6754B • Rev.1.0.0
Marking Information
Pin Configuration
Pin Definitions
Pin #
1
2
3
4
5
6
7
8
ZXYTT
6754MR
BTPM
SENSE
Name Description
GATE
GND
VDD
NC
HV
RT
FB
Ground. This pin is used for the ground potential of all the pins. A 0.1µF decoupling capacitor
placed between VDD and GND is recommended.
Feedback. The output voltage feedback information from the external compensation circuit is fed
into this pin. The PWM duty cycle is determined by this pin and the current-sense signal from Pin
6. FAN6754B performs open-loop protection (OLP); if the FB voltage is higher than a threshold
voltage (around 4.6V) for more than 56ms, the controller latches off the PWM.
No Connection
High-Voltage Startup. This pin is connected to the line input via a 1N4007 and 200k resistor to
achieve brownout and high/low line compensation. Once the voltage on the HV pin is lower than
the brownout voltage, PWM output turns off. High/low line compensation dominates the cycle-by-
cycle current limiting to achieve constant output power limiting with universal input.
Over-Temperature Protection. An external NTC thermistor is connected from this pin to GND.
The impedance of the NTC decreases at high temperatures. Once the voltage on the RT pin
drops below the threshold voltage, the controller latches off the PWM. If RT pin is not connected
to NTC resistor for Over-Temperature Protection, a 100K series one resistor is recommended
to ground to prevent from noise interference. This pin is limited by an internal clamping circuit.
Current Sense. This pin is used to sense the MOSFET current for the current-mode PWM and
current
Supply Voltage. IC operating current and MOSFET driving current are supplied using this pin.
This pin is connected to an external bulk capacitor of typically 47µF. The threshold voltages for
turn-on and turn-off are 17V and 10V, respectively. The operating current is lower than 2mA.
Gate Drive Output. The totem-pole output driver for the power MOSFET. It is internally clamped
below 13V.
limiting.
The version doesn’t have internal SSCP function.
Figure 4. Pin Configuration (Top View)
GND
NC
HV
FB
ZXYTT
6754ML
BTPM
Figure 3. Top Mark
1
2
3
4
SOP-8
3
8
7
6
5
SENSE
GATE
VDD
RT
F - Fairchild Logo
Z - Plant Code
X - 1-Digit Year Code
Y - 1-Digit Week Code
TT - 2-Digit Die Run Code
T - Package Type (M=SOP)
P - Y: Package (Green)
M - Manufacture Flow Code
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