FAN2108 Fairchild Semiconductor, FAN2108 Datasheet - Page 3

• Manufacturer Part Number: FAN2108
• Description: This part is covered in Fairchild's href="http://www
• Manufacturer: Fairchild Semiconductor

© 2008 Fairchild Semiconductor Corporation
FAN2108 • Rev. 1.0.1
Pin Configuration
Pin Definitions
P3, 21-23
P1, 6-12
P2, 2-5
Pin #
13
14
15
16
17
18
19
20
24
25
1
PGOOD
Name
COMP
PGND
BOOT
AGND
RAMP
VCC
ILIM
R(T)
SW
VIN
NC
EN
FB
Description
Switching Node.
Power Input Voltage. Connect to the main input power source.
Power Ground. Power return and Q2 source.
High-Side Drive BOOT Voltage. Connect through capacitor (C
includes an internal synchronous bootstrap diode to recharge the capacitor on this pin to
V
Power-Good Flag. An open-drain output that pulls LOW when FB is outside a ±10% range
of the reference. PGOOD does not assert HIGH until the fault latch is enabled.
ENABLE. Enables operation when pulled to logic HIGH or left open. Toggling EN resets the
regulator after a latched fault condition. This input has an internal pull-up when the IC is
functioning normally. When a latched fault occurs, EN is discharged by a current sink.
Input Bias Supply for IC. The IC’s logic and analog circuitry are powered from this pin.
Analog Ground. The signal ground for the IC. All internal control voltages are referred to
this pin. Tie this pin to the ground island/plane through the lowest impedance connection.
Current Limit. A resistor (R
limit trip threshold lower than the default setting.
Oscillator Frequency. A resistor (R
frequency.
Output Voltage Feedback. Connect through a resistor divider to the output voltage.
Compensation. Error amplifier output. Connect the external compensation network
between this pin and FB.
No Connect. This pin is not used.
Ramp Amplitude. A resistor (R
and provides voltage feedforward functionality.
CC
when SW is LOW.
Figure 3. MLP 5x6mm Pin Configuration (Bottom View)
ILIM
) from this pin to AGND can be used to program the current-
RAMP
3
) connected from this pin to V
T
) from this pin to AGND sets the PWM switching
BOOT
IN
sets the ramp amplitude
) to SW. The IC
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