FAN102MY Fairchild Semiconductor, FAN102MY Datasheet - Page 11

• Manufacturer Part Number: FAN102MY
• Description: IC CTRLR PWM GREEN CV/CC 8SOP
• Manufacturer: Fairchild Semiconductor

Specifications of FAN102MY

• Output Isolation: Isolated
• Frequency Range: 39 ~ 45kHz
• Voltage - Input: 5.5 ~ 15 V
• Voltage - Output: 30V
• Power (watts): 660mW
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Number Of Outputs: 1
• Duty Cycle (max): 75 %
• Mounting Style: SMD/SMT
• Switching Frequency: 45 KHz
• Maximum Operating Temperature: + 105 C
• Fall Time: 80 ns
• Minimum Operating Temperature: - 40 C
• Rise Time: 200 ns
• Synchronous Pin: No
• Topology: Flyback
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: FAN102MYTR

© 2008 Fairchild Semiconductor Corporation
FAN102 Rev. 1.0.3
Cable Voltage Drop Compensation
When it comes to cellular phone charger applications,
the actual battery is located at the end of cable, which
causes typically several percent of voltage drop on the
actual battery voltage. FAN102 has a programmable
cable voltage drop compensation, which provides a
constant output voltage at the end of the cable over the
entire load range in CV mode. As load increases, the
voltage drop across the cable is compensated by
increasing the reference voltage of voltage regulation
error amplifier. The amount of compensation is
programmed by the resistor on the COMR pin. The
relationship between the amount of compensation and
COMR resistor is shown in Figure 26.
Temperature Compensation
Built-in temperature compensation provides constant
voltage regulation over a wide range of temperature
variation.
compensates the forward-voltage drop variation of the
secondary-side rectifier diode.
Green-Mode Operation
The FAN102 uses voltage regulation error amplifier
output (V
modulates the PWM frequency, as shown in Figure 27,
such that the switching frequency decreases as load
decreases. In heavy load conditions, the switching
frequency is fixed at 42KHz. Once V
below 2.8V, the PWM frequency starts to linearly
decrease from 42KHz to 550Hz to reduce the switching
losses. As V
frequency is fixed at 550Hz and FAN102 enters deep
green mode, where the operating current reduces to
1mA, further reducing the standby power consumption.
15
14
13
12
11
10
Figure 26. Cable Voltage Drop Compensation
9
8
7
6
5
4
3
2
1
10
COMV
This
COMV
) as an indicator of the output load and
20
decreases below 0.8V, the switching
30
internal
40
R
COMR
50
(k )
compensation
60
70
COMV
80
decreases
90
current
100
11
Frequency Hopping
EMI reduction is accomplished by frequency hopping,
which spreads the energy over a wider frequency range
than the bandwidth measured by the EMI test
equipment. FAN102 has an internal frequency hopping
circuit that changes the switching frequency between
39.4kHz and 44.6kHz with a period of 3ms, as shown in
Figure 28.
42kHz
550H z
42.0kHz
44.6kHz
39.4kHz
Switching Frequen cy
Figure 27. Switching Frequency in Green Mode
Green
Mode
Deep
Gate Drive Signal
f
s
Figure 28. Frequency Hopping
0.8V
t
t
t
s
s
s
44.6kHz
Green Mode
3ms
2.8V
Normal Mode
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V
COMV
t