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Fuji Electric |
FA3641P(N), FA3647P(N)FA3641P(N), FA3647P(N)
PWM control IC with light load power saving function
For Switching Power Supply Control
s Description
The FA3641P(N) and FA3647P(N) are the PWM type switching
power supply control ICs that can directly drive power MOSFET.
These ICs use a CMOS device with high dielectric strength
(30V) to implement low power consumption. They feature a
number of functions that are equivalent to those of the FA531X
series consisting of bipolar devices. In addition, they have a
function that reduces the oscillation frequency to suppress loss
of the power supply in light load mode and support an
overvoltage protection detecting Vcc voltage. These ICs are
most suitable for high-performance, energy-saving power
supplies that require low input power in standby or no-load
mode.
s Features
• Uses a newly developed CMOS process with high dielectric
strength (30V) for implementing low power consumption
• Standby current of 2µA or less (at Vcc=14V), and operating
current of 1.9mA (typ.)
• Automatically reduces the oscillation frequency to suppress
loss of the power supply in light load mode
• Overvoltage protection function detecting Vcc voltage
• A drive circuit for connecting a power MOSFET directly
• Output peak current: Source current –500mA
Sink current
+1A
• Pulse-by-pulse overcurrent limiting function
• Overload cutoff function (latch or non-latch mode selectable)
• Output ON/OFF control function by external signal
• Latch mode overvoltage shutdown function
• Undervoltage lockout function
(16.5V ON / 9V OFF)
• Reference voltage output (5V)
• 8-pin package (DIP/SOP)
s Dimensions, mm
SOP-8
85
14
4.9
0.4±0.1 1.27±0.2
DIP-8
8
5
1 9.3 4
1.5
2.54±0.25 0.46±0.1
7.62
0~15˚
0.25+–00.1.05
0~15˚
58
s Block diagram
FA3641
FA3647
FA3641P(N), FA3647P(N)
Pin No. Symbol Function
Description
1 RT Oscillator timing Setting oscillation frequency
resistor
2 FB Feedback
Input to PWM comparator
3 IS (+)/ Overcurrent Input to overcurrent limiting
IS (–) detection
function
4 GND Ground
Ground
5 OUT Output
Output for direct driving a
power MOSFET
6
VCC Power supply
Power supply for IC
7 REF Reference voltage Reference voltage output
(5V)
8 CS Soft-start and Soft-start, ON/OFF and latch-
ON/OFF control mode shutdown operations
s Absolute maximum ratings (Ta=25˚C)
Item
Supply voltage
Output peak current
FB pin input voltage
REF pin output current
IS pin input voltage
CS pin input current
Total power dissipation
Operating temperature
Junction temperature
Storage temperature
Symbol
VCC1
VCC2
IOL
IOH
VFB
IREF
VIS
ICS
Pd
Topr
Tj
Tstg
Test condition
Low impedance source (Icc >15mA)
Internal ZD clamp (Icc < 15mA)
Sink current
Source current
at Ta =25˚C
DIP
SOP
Rating
30
Self limiting
+1.0
–0.5
–0.3 to 5.0
–10
–0.3 to 5.0
2.0
800 *1
400 *2
–30 to +85
125
–40 to +150
Unit
V
V
A
A
V
mA
V
mA
mW
˚C
˚C
˚C
Note: *1 Derating factor Ta > 25˚C: 8.0mW/˚C
*2 Derating factor Ta > 25˚C: 4.0mW/˚C
Maximum power dissipation curve
400mW (SOP)
800mW (DIP)
0
–30 25
85 125
Ambient temperature Ta [˚C]
59
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