April 2012
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3
FAN6754A — Highly Integrated Green-Mode PWM Controller
FAN6754A
Highly Integrated Green- Mode PWM Controller
Brownout and VLimit Adjustment by HV Pin
Features
High-Voltage Startup
AC Input Brownout Protection with Hysteresis
Monitor HV to Adjust VLimit
Low Operating Current: 1.5mA
Linearly Decreasing PWM Frequency to 22KHz
Frequency Hopping to Reduce EMI Emission
Fixed PWM Frequency: 65KHz
Peak-Current-Mode Control
Cycle-by-Cycle Current Limiting
Leading-Edge Blanking (LEB)
Internal Open-Loop Protection
GATE Output Maximum Voltage Clamp: 13V
VDD Under-Voltage Lockout (UVLO)
VDD Over-Voltage Protection (OVP)
Programmable Over-Temperature Protection (OTP)
Internal Latch Circuit (OVP, OTP)
Open-Loop Protection (OLP); Restart for MR, Latch
for ML
SENSE Short-Circuit Protection (SSCP)
Built-in 8ms Soft-Start Function
Applications
General-purpose switch-mode power supplies and
flyback power converters, including:
Power Adapters
Description
The highly integrated FAN6754A PWM controller
provides several features to enhance the performance
of flyback converters. To minimize standby power
consumption, a proprietary green-mode function
provides off-time modulation to continuously decrease
the switching frequency under light-load conditions.
Under zero-load and very light-load conditions,
FAN6754A saves PWM pulses by entering deep burst
mode. This burst mode function enables the power
supply to meet international power conservation
requirements.
FAN6754A integrates a frequency-hopping function
internally to reduce EMI emission of a power supply with
minimum line filters. Built-in synchronized slope
compensation is accomplished by proprietary HV
monitor to adjust VLimit for constant output power limit
over universal AC input range. The gate output is
clamped at 13V to protect the external MOSFET from
over-voltage damage.
Other protection functions include AC input brownout
protection with hysteresis, SENSE pin short-circuit
protection, and VDD over-voltage protection. For over-
temperature protection, an external NTC thermistor can
be applied to sense the external switcher’s temperature.
When VDD OVP or OTP are activated, an internal latch
circuit is used to latch-off the controller. The latch mode
is reset when the VDD supply is removed.
FAN6754A is available in an 8-pin SOP package.
Related Resources
Evaluation Board: FEBFAN6754AMR_CP450v1
Ordering Information
Part Number Operating
Temperature Range Package Packing Method
FAN6754AMRMY -40 to +105°C 8-Pin, Small Outline Package (SOP) Tape & Reel
FAN6754AMLMY
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 2
FAN6754A — Highly Integrated Green-Mode PWM Controller
Application Diagram
Figure 1. Typical Application
Internal Block Diagram
GATE
FB
SENSE
GND
VDD
RT 5
HV
Startup
5V
Soft
Driver
QS
R
1.05V
17V/10V
UVLO
Green
Mode
OSC
Blanking
Circuit
OLP
OVP
Delay
Debounce
VDD-OVP
VLimit Adjustment
0.7V
7
4 3
8
2
6
tD-OTP1
Counter
4.6V
NCHV
Line Voltage
Sample Circuit
Brownout Protection
OTP OLP
Latch
Protection
OVP
OTP
OLP for ML
3R
OLP
Comparator
PWM
Comparator
Internal
BIAS
IRT
tD-OTP2
Counter
Soft-Start
VLimit
Slope
Compensation
R
Current Limit
Comparator
Soft-Start
Comparator
1
OLP for MR
Re-Start
Protection
SSCP
Delay 0.05V
SSCP
SSCP
Comparator
SSCP
Figure 2. Functional Block Diagram
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 3
FAN6754A — Highly Integrated Green-Mode PWM Controller
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
Marking Information
Figure 3. Top Mark
Pin Configuration
SOP-8
GND
SENSE
VDD
RT
GATE
HV
NC
FB
18
7
6
54
2
3
Figure 4. Pin Configuration (Top View)
Pin Definitions
Pin # Name Description
1 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.
2 FB
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. FAN6754A 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.
3 NC
No Connection
4 HV
High-Voltage Startup. This pin is connected to the line input via a 1N4007 and 200kΩ 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.
5 RT
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 100KΩ series one resistor is recommended
to ground to prevent from noise interference. This pin is limited by an internal clamping circuit.
6 SENSE
Current Sense. This pin is used to sense the MOSFET current for the current-mode PWM and
current limiting.
7 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 47µF. The threshold voltages for
turn-on and turn-off are 17V and 10V, respectively. The operating current is lower than 2mA.
8 GATE
Gate Drive Output. The totem-pole output driver for the power MOSFET. It is internally clamped
below 13V.
ZXYTT
6754MR
A
TPM
ZXYTT
6754ML
A
TPM
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 4
FAN6754A — Highly Integrated Green-Mode PWM Controller
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only.
Symbol Parameter Min. Max. Unit
VVDD DC Supply Voltage(1,2) 30 V
VFB FB Pin Input Voltage -0.3 7.0 V
VSENSE SENSE Pin Input Voltage -0.3 7.0 V
VRT RT Pin Input Voltage -0.3 7.0 V
VHV HV Pin Input Voltage 500 V
PD Power Dissipation (TA50°C) 400 mW
ΘJA Thermal Resistance (Junction-to-Air) 150 °C/W
TJ Operating Junction Temperature -40 +125
°C
TSTG Storage Temperature Range -55 +150 °C
TL Lead Temperature (Wave Soldering or IR, 10 Seconds) +260 °C
ESD Electrostatic Discharge Capability,
All Pins Except HV Pin
Human Body Model;
JESD22-A114 4500
V
Charged Device Model;
JESD22-C101 1500
Notes:
1. All voltage values, except differential voltages, are given with respect to the network ground terminal.
2. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.
3. ESD with HV pin: CDM=1000V and HBM=500V.
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol Parameter Min. Typ. Max. Unit
TA Operating Ambient Temperature -40 +105 °C
RHV HV Startup Resistor 150 200 250 kΩ
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 5
FAN6754A — Highly Integrated Green-Mode PWM Controller
Electrical Characteristics
VDD=15V and TA=25°C unless otherwise noted.
Symbol Parameter Conditions Min. Typ. Max. Units
VDD Section
VOP Continuously Operating Voltage 24 V
VDD-ON Start Threshold Voltage 16 17 18 V
VDD-OFF Minimum Operating Voltage 9 10 11 V
VDD-OLP I
DD-OLP Off Voltage 5.5 6.5 7.5 V
VDD-LH Threshold Voltage on VDD Pin for
Latch-Off Release Voltage 3.5 4.0 4.5 V
VDD-AC
Threshold Voltage on VDD Pin for
Disable AC Recovery to Avoid
Startup Failed
VDD-OFF
+2.8
VDD-OFF
+3.3
VDD-OFF
+3.8 V
IDD-ST Startup Current VDD-ON – 0.16V 30 µA
IDD-OP1 Operating Supply Current,
PWM Operation
VDD=20V, FB=3V Gate
Open 1.5 2.0 mA
IDD-OP2 Operating Supply Current,
Gate Stop VDD=20V, FB=3V 1.0 1.5 mA
ILH
Operating Current at PWM-Off
Phase Under Latch-Off
Conduction
VDD=5V 30 60 90 µA
IDD-OLP Internal Sink Current Under Latch-
Off Conduction VDD-OLP+0.1V 170 200 230 µA
VDD-OVP V
DD Over-Voltage Protection 24 25 26 V
tD-VDDOVP VDD Over-Voltage Protection
Debounce Time 75 165 255 µs
HV Section
IHV Supply Current from HV Pin VAC=90V(VDC=120V),
VDD=0V 2.0 3.5 5.0 mA
IHV-LC Leakage Current after Startup HV=700V, VDD=VDD-
OFF+1V 1 20 µA
VAC-OFF Brownout Threshold
DC Source Series
R=200kΩ to HV Pin
See Equation 1
92 102 112 V
VAC-ON Brownin Threshold
DC Source Series
R=200k to HV Pin
See Equation 2
104 114 124 V
ΔVAC VAC-ON - VAC-OFF DC Source Series
R=200k to HV Pin 6 12 18 V
tS-CYCLE Line Voltage Sample Cycle FB > VFB-N 220
µs
FB < VFB-G 650
tH-TIME Line Voltage Hold Period 20 µs
tD-AC-OFF PWM Turn-off Debounce Time FB > VFB-N 65 75 85 ms
FB < VFB-G 180 235 290 ms
Continued on page the following page…
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 6
FAN6754A — Highly Integrated Green-Mode PWM Controller
Figure 5. Brownout Circuit
Gate
VIN-OFF
VIN-ON
Brownout debounce time
VIN
Gate start Gate stop
Figure 6. Brownout Behavior
Figure 7. VDD-AC and AC Recovery
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 7
FAN6754A — Highly Integrated Green-Mode PWM Controller
Electrical Characteristics (Continued)
VDD=15V and TA=25°C unless otherwise noted.
Symbol Parameter Conditions Min. Typ. Max. Units
Oscillator Section
fOSC Frequency in Normal Mode Center Frequency 61 65 69
KHz
Hopping Range ±3.7 ±4.2 ±4.7
tHOP Hopping Period FB > VFB-N 3.9 4.4 4.9 ms
FB=VFB-G 10.2 11.5 12.8 ms
fOSC-G Green-Mode Frequency 19 22 25 KHz
fDV Frequency Variation vs. VDD Deviation VDD=11V to 22V 5 %
fDT Frequency Variation vs. Temperature Deviation TA=-40 to +105°C 5 %
Feedback Input Section
AV Input Voltage to Current-Sense Attenuation 1/4.5 1/4.0 1/3.5 V/V
ZFB Input Impedance 14 16 18 k
VFB-OPEN Output High Voltage FB Pin Open 4.8 5.0 5.2 V
VFB-OLP FB Open-Loop Trigger Level 4.3 4.6 4.9 V
tD-OLP Delay Time of FB Pin Open-Loop Protection 50 56 62 ms
VFB-N Green-Mode Entry FB Voltage
Pin, FB Voltage
(FB =VFB-N) 2.6 2.8 3.0 V
Hopping Range ±3.7 ±4.2 ±4.7 kHz
VFB-G Green-Mode Ending FB Voltage
Pin, FB Voltage
(FB =VFB-G) 2.1 2.3 2.5 V
Hopping Range ±1.27 ±1.45 ±1.62 kHz
VFB-ZDCR FB Threshold Voltage for Zero-Duty Recovery 1.9 2.1 2.3 V
VFB-ZDC FB Threshold Voltage for Zero-Duty 1.8 2.0 2.2 V
Continued on the following page…
Figure 8. VFB vs. PWM Frequency
PWM Frequency
fOSC
fOSC-G
VFB-N
VFB-G
VFB-ZDC VFB
VFB-ZDCR
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 8
FAN6754A — Highly Integrated Green-Mode PWM Controller
Electrical Characteristics (Continued)
VDD=15V and TA=25°C unless otherwise noted.
Symbol Parameter Conditions Min. Typ. Max. Unit
s
Current-Sense Section
tPD Delay to Output 100 250 ns
tLEB Leading-Edge Blanking Time 230 280 330 ns
VLimit-L Current Limit at Low Line (VAC=86V) VDC=122V, Series R=200kΩ
to HV 0.43 0.46 0.49 V
VLimit-H Current Limit at High Line (VAC=259V) VDC=366V, Series R=200k
to HV 0.36 0.39 0.42 V
VSSCP Threshold Voltage for SENSE Short-Circuit Protection 0.03 0.05 0.07 V
tON-SSCP On Time for VSSCP Checking 4.0 4.4 4.8 µs
tD-SSCP Delay for SENSE Short-Circuit Protection VSENSE<0.05V 60 120 180 µs
tSS Soft-Start Time Startup Time 7 8 9 ms
GATE Section
DCYMAX Maximum Duty Cycle 86 89 92 %
VGATE-L Gate Low Voltage VDD=15V, IO=50mA 1.5 V
VGATE-H Gate High Voltage VDD=12V, IO=50mA 8 V
IGATE-SINK Gate Sink Current(4) VDD=15V 300 mA
IGATE-
SOURCE Gate Source Current(4) VDD=15V, GATE=6V 250 mA
tr Gate Rising Time VDD=15V, CL=1nF 100
ns
tf Gate Falling Time VDD=15V, CL=1nF 50
ns
VGATE-
CLAMP Gate Output Clamping Voltage VDD=22V 9 13 17
V
RT Section
IRT Output Current from RT Pin 92 100 108 µA
VRTTH1 Over-Temperature Protection Threshold
Voltage
0.7V VRT 1.05V, after
12ms Latch Off 1.000 1.035 1.070
V
VRTTH2 VRT 0.7V, After 100µs
Latch Off 0.65 0.70 0.75
tD-OTP1
Over-Temperature Latch-Off Debounce
VRTTH2 VRT VRTTH1
FB > VFB-N 14 16 18
ms
VRTTH2 VRT VRTTH1
FB < VFB-G 40 51 62
tD-OTP2 VRT< VRTTH2, FB > VFB-N 110 185 260
µs
VRT< VRTTH2, FB < VFB-G 320 605 890
Note:
4. Guaranteed by design.
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 9
FAN6754A — Highly Integrated Green-Mode PWM Controller
Typical Performance Characteristics
Figure 9. Startup Current (IDD-ST) vs. Temperature Figure 10. Operation Supply Current (IDD-OP1)
vs. Temperature
Figure 11. Start Threshold Voltage (VDD-ON)
vs. Temperature Figure 12. Minimu m Op erating Voltage (VDD-OFF)
vs. Temperature
Figure 13. Supply Current Drawn from HV Pin (IHV)
vs. Temperature Figure 14. HV Pin Leakage Current After Startup
(IHV-LC) vs. Temperature
Figure 15. Frequency in Normal Mode (fOSC)
vs. Temperature Figure 16. Maximum Duty Cycle (DCYMAX)
vs. Temperature
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 10
FAN6754A — Highly Integrated Green-Mode PWM Controller
Typical Performance Characteristics (Continued)
Figure 17. FB Open-Loop Trigger Level (VFB-OLP)
vs. Temperature Figure 18. Delay Time of FB Pin Open-Loop
Protection (tD-OLP) vs. Temperature
Figure 19. VDD Over-Voltage Protection (VDD-OVP)
vs. Temperature Figure 20. Output Current from RT Pin (IRT)
vs. Temperature
Figure 21. Over-Temperature Protection Threshold
Voltage (VRTTH1) vs. Temperature Figure 22. Over-Temperature Protection Threshold
Voltage (VRTTH2) vs. Temperature
Figure 23. Brownin (VAC-ON) vs. Temperature Figure 24. Brownout (VAC-OFF) vs. Temperature
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 11
FAN6754A — Highly Integrated Green-Mode PWM Controller
Functional Description
Startup Current
For startup, the HV pin is connected to the line input
through an external diode and resistor; RHV, (1N4007 /
200K recommended). Peak startup current drawn from
the HV pin is (VAC×2) / RHV and charges the hold-up
capacitor through the diode and resistor. When the VDD
capacitor level reaches VDD-ON, the startup current
switches off. At this moment, the VDD capacitor only
supplies the FAN6754A to keep the VDD until the
auxiliary winding of the main transformer provides the
operating current.
Operating Current
Operating current is around 1.5mA. The low operating
current enables better efficiency and reduces the
requirement of VDD hold-up capacitance.
Green-Mode Operation
The proprietary green-mode function provides off-time
modulation to reduce the switching frequency in light-
load and no-load conditions. VFB, which is derived from
the voltage feedback loop, is taken as the reference.
Once VFB is lower than the threshold voltage (VFB-N), the
switching frequency is continuously decreased to the
minimum green-mode frequency of around 22KHz.
Current Sensing / PWM Current Limiting
Peak-current-mode control is utilized to regulate output
voltage and provide pulse-by-pulse current limiting. The
switch current is detected by a sense resistor into the
SENSE pin. The PWM duty cycle is determined by this
current-sense signal and VFB, the feedback voltage.
When the voltage on the SENSE pin reaches around
VCOMP = (VFB–0.6)/4, the switch cycle is terminated
immediately. VCOMP is internally clamped to a variable
voltage around 0.46V for low-line output power limit.
Leading-Edge Blanking (LEB)
Each time the power MOSFET is switched on, a turn-on
spike occurs on the sense-resistor. To avoid premature
termination of the switching pulse, a leading-edge
blanking time is built in. During this blanking period, the
current-limit comparator is disabled and cannot switch
off the gate driver.
Under-Voltage Lockout (UVLO)
The turn-on and turn-off thresholds are fixed internally at
17V and 10V, respectively. During startup, the hold-up
capacitor must be charged to 17V through the startup
resistor to enable the IC. The hold-up capacitor
continues to supply VDD until the energy can be
delivered from auxiliary winding of the main transformer.
VDD must not drop below 10V during startup. This UVLO
hysteresis window ensures that hold-up capacitor is
adequate to supply VDD during startup.
Gate Output / Soft Driving
The BiCMOS output stage is a fast totem-pole gate
driver. Cross conduction has been avoided to minimize
heat dissipation, increase efficiency, and enhance
reliability. The output driver is clamped by an internal
13V Zener diode to protect power MOSFET transistors
against undesirable gate over voltage. A soft driving
waveform is implemented to minimize EMI.
Soft-Start
For many applications, it is necessary to minimize the
inrush current at startup. The built-in 8ms soft-start
circuit significantly reduces the startup current spike and
output voltage overshoot.
Slope Compensation
The sensed voltage across the current-sense resistor is
used for peak-current-mode control and cycle-by-cycle
current limiting. Built-in slope compensation improves
stability and prevents sub-harmonic oscillation.
FAN6754A inserts a synchronized, positive-going, ramp
at every switching cycle.
Constant Output Power Limit
When the SENSE voltage across sense resistor RSENSE
reaches the threshold voltage, around 0.46V for low-line
condition, the output GATE drive is turned off after a
small delay, tPD. This delay introduces an additional
current proportional to tPD • VIN / LP. Since the delay is
nearly constant regardless of the input voltage VIN,
higher input voltage results in a larger additional current
and the output power limit is higher than under low input
line voltage. To compensate this variation for a wide AC
input range, a power-limiter is controlled by the HV pin
to solve the unequal power-limit problem. The power
limiter is fed to the inverting input of the current limiting
comparator. This results in a lower current limit at high-
line inputs than at low-line inputs.
Brownout and Constant Power Limited by
the HV Pin
Unlike previous PWM controllers, FAN6754A’s HV pin
can detect the AC line voltage brownout function and
adjust the current limit. Using a fast diode and startup
resistor to sample the AC line voltage, the peak value
refreshes and is stored in a register at each sampling
cycle. When internal update time is met, this peak value
is used for brownout and current-limit level judgment.
Equation 1 and 2 calculate the level of brownin or
brownout converted to RMS value. For power saving,
FAN6754A enlarges the sampling cycle to lower the
power loss from HV sampling at light-load condition.
2 / )
1.61.6) (R
0.9V ( (RMS) V
HV
ON- AC
+
×= (1)
2 / )
1.61.6) (R
0.81V ( (RMS) V HV
OFF- AC +
×= (2)
where RHV is in kΩ.
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 12
FAN6754A — Highly Integrated Green-Mode PWM Controller
The HV pin can perform current limit to shrink the
tolerance of Over-Current Protection (OCP) under full
range of AC voltage, to linearly current limit curve, as
shown in Figure 25. FAN6754A also shrinks the Vlimit
level by half to lower the I2RSENSE loss to increase the
heavy-load efficiency.
0.38
0.39
0.4
0.41
0.42
0.43
0.44
0.45
0.46
0.47
100 120 140 160 180 200 220 240 260 280 300 320 340 360 380
DC Voltage on HV Pin (V)
Vlimit (V)
Figure 25. Linearly Current Limit Curve
VDD Over-Voltage Protection (OVP)
VDD over-voltage protection prevents damage due to
abnormal conditions. If the VDD voltage is over the over-
voltage protection voltage (VDD-OVP) and lasts for tD-
VDDOVP, the PWM pulses are disabled until VDD drops
below the UVLO, then starts again. Over-voltage
conditions are usually caused by open feedback loops.
Sense-Pin Short-Circuit Protection
The FAN6754A provides safety protection for Limited
Power Source (LPS) tests. When the sense resistor is
shorted by soldering during production, the pulse-by-
pulse current limiting loses efficiency for the purpose of
providing over-power protection for the unit. The unit
may be damaged when the loading is larger than the
maximum load. To protect against a short circuit across
the current-sense resistor, the controller is designed to
immediately shut down if a continuously low voltage
(around 0.05V/120µs) on the SENSE pin is detected.
Thermal Protection
An NTC thermistor, RNTC, in series with resistor RA, can
be connected from the RT pin to ground. A constant
current, IRT, is output from the RT pin. The voltage on
the RT pin can be expressed as VRT=IRT • (RNTC + RPTC),
where IRT is 100µA. At high ambient temperature, RNTC
is smaller, such that VRT decreases. When VRT is less
than 1.035V (VRTTH1), the PWM turns off after 16ms
(tD-OTP1). If VRT is less than 0.7V (VRTTH2), the PWM turns
off after 185µs (tD-OTP2). If the RT pin is not connected to
NTC resistor for over-temperature protection,
connecting a series one 100KΩ resistor to ground to
prevent from noise interference is recommended. This
pin is limited by an internal clamping circuit.
Limited Power Control
The FB voltage increases every time the output of the
power supply is shorted or overloaded. If the FB voltage
remains higher than a built-in threshold for longer than
tD-OLP, PWM output is turned off. As PWM output is
turned off, VDD begins decreasing.
When VDD goes below the turn-off threshold (10V) the
controller is totally shut down and VDD is continuously
discharged to VDD-OLP (6.5V) by I
DD-OLP to lower the
average input power. This is called two-level UVLO. VDD
is cycled again. This protection feature continues as
long as the overloading condition persists. This prevents
the power supply from overheating due to overloading
conditions.
Noise Immunity
Noise on the current sense or control signal may cause
significant pulse-width jitter, particularly in continuous-
conduction mode. Slope compensation helps alleviate
this problem. Good placement and layout practices
should be followed. Avoiding long PCB traces and
component leads, locating compensation and filter
components near the FAN6754A, and increasing the
power MOS gate resistance improve performance.
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 13
FAN6754A — Highly Integrated Green-Mode PWM Controller
Physical Dimensions
SEE DETAIL A
NOTES: UNLESS OTHERWISE SPECIFIED
A) THIS PACKAGE CONFORMS TO JEDEC
MS-012, VARIATION AA, ISSUE C,
B) ALL DIMENSIONS ARE IN MILLIMETERS.
C) DIMENSIONS DO NOT INCLUDE MOLD
FLASH OR BURRS.
D) LANDPATTERN STANDARD: SOIC127P600X175-8M.
E) DRAWING FILENAME: M08AREV13
LAND PATTERN RECOMMENDATION
SEATING PLANE
0.10 C
C
GAGE PLANE
x 45°
DETAIL A
SCALE: 2:1
PIN ONE
INDICATOR
4
8
1
C
MBA0.25
B
5
A
5.60
0.65
1.75
1.27
6.20
5.80
3.81
4.00
3.80
5.00
4.80
(0.33)
1.27
0.51
0.33
0.25
0.10
1.75 MAX
0.25
0.19
0.36
0.50
0.25
R0.10
R0.10
0.90
0.406 (1.04)
OPTION A - BEVEL EDGE
OPTION B - NO BEVEL EDGE
Figure 26. 8-Pin Small Outline Package (SOP) Package
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or
obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions,
specifically the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN6754A • Rev. 1.0.3 14
FAN6754A— Highly Integrated Green-Mode PWM Controller