FAN6747 Datasheet, PDF (3/15 Pages) Fairchild Semiconductor – Highly Integrated Green-Mode PWM Controller

Marking Information
ZXYTT
6747F
TPM
Pin Configuration
: Fairchild Logo
Z: Plant Code
X: Year Code
Y: Week Code
TT: Die Run Code
F: L = OCP latch
T: Package Type (N =DIP, M = SOP)
P: Y = Green Compound
M: Manufacturing Flow Code
Figure 3. Top Mark
Pin Definitions
Figure 4. Pin Assignments
Pin #
1
2
3
4
5
6
7
8
Name Description
GND
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
FB into this pin. The PWM duty cycle is determined from this pin and the current-sense signal from
Pin 6.
NC 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
HV 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
RT
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.
Current Sense. This pin is used to sense the MOSFET current for the current mode PWM and
SENSE OCP. If the switching current is higher than OCP threshold and lasts 220ms, the controller
latches off the PWM.
VDD
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
Gate Driver Output. The totem-pole output driver for the power MOSFET. It is internally
clamped below 14V.
© 2009 Fairchild Semiconductor Corporation
FAN6747 • Rev. 1.0.1
3
www.fairchildsemi.com