FAN2103 Datasheet, PDF (3/14 Pages) Fairchild Semiconductor – 3A, 24V Input Integrated Synchronous Buck Regulator

Pin Configuration
Figure 3. MLP 5x6mm Pin Configuration (Bottom View)
Pin Definitions
Pin
P1, 6-12
P2, 2-5
P3, 21-23
1
13
14
15
16
17
18
19
20
24
25
Name
SW
VIN
PGND
BOOT
PGOOD
EN
VCC
AGND
ILIM
R(T)
FB
COMP
PWM#
RAMP
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 (CBOOT) to SW. The IC includes
an internal synchronous bootstrap diode to recharge the capacitor on this pin to VCC when
SW is LOW.
Power-Good Flag. An open-drain output that pulls LOW when FB is outside a ±10% range
of the reference when EN is HIGH. 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 (RILIM) from this pin to AGND can be used to program the current-
limit trip threshold lower than the default setting.
Oscillator Frequency. A resistor (RT) from this pin to AGND sets the PWM switching
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.
Power Save Mode / Forced PWM. Connect to VCC to enable light-load, power-saving mode
of operation. Connect to GND or leave open for fixed-frequency PWM mode.
Ramp Amplitude. A resistor (RRAMP) connected from this pin to VIN sets the ramp
amplitude and provides voltage feedforward functionality.
© 2007 Fairchild Semiconductor Corporation
FAN2103 Rev. 1.0.3
3
www.fairchildsemi.com