FAN6747 Fairchild Semiconductor, FAN6747 Datasheet - Page 3

• Manufacturer Part Number: FAN6747
• Description: The highly integrated FAN6747 PWM controller provides several features to enhance the performance of flyback converters
• Manufacturer: Fairchild Semiconductor

© 2010 Fairchild Semiconductor Corporation
FAN6747 • Rev. 1.0.3
Marking Information
Pin Configuration
Pin Definitions
Pin #
1
2
3
4
5
6
7
8
SENSE
Name
GATE
GND
VDD
NC
HV
FB
RT
Description
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 from this pin and the current-sense signal from
Pin 6.
No Connection.
High-Voltage Startup. This pin is connected to the line input via diodes and resistors to achieve
brownout and high/low line compensation. Once the voltage of the HV pin is lower than the
brownout voltage, PWM output is turned off. High/low line compensation dominates the OCP
level and cycle-by-cycle current limit, to solves the unequal OCP level and power limit problem
under universal input.
Over-Temperature Protection. For 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 of the RT pin drops below the threshold voltage, the controller latches off the
PWM. If the RT pin is not connected to the NTC resistor for over temperature protection, it is
recommended to connect one 100KΩ resistor to ground to prevent noise interference. This pin is
limited by internal clamping circuit.
Current Sense. This pin is used to sense the MOSFET current for the current mode PWM and
OCP. If the switching current is higher than OCP threshold and lasts 220ms, the controller
latches off the PWM.
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 10µF. The threshold voltages for
startup and turn-off are 16.5V and 9V, respectively. The operating current is lower than 2mA.
Gate Driver Output. The totem-pole output driver for the power MOSFET. It is internally
clamped below 14V.
6747F
TPM
ZXYTT
Figure 4. Pin Assignments
Figure 3. Top Mark
Z:
X:
Y:
TT:
F:
T: Package Type (N =DIP, M = SOP)
P:
M:
: Fairchild Logo
Plant Code
Week Code
L = OCP latch
Y = Green Compound
Year Code
Manufacturing Flow Code
3
Die Run Code
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