Diodes AP3581A/B/C - Manual (Page 2)

Data Sheet
Single Phase Synchronous Buck PWM Controller AP3581A/B/C
Oct. 2011 Rev. 1. 0 BCD Semiconductor Manufacturing Limited
2
Pin Configuration
MP Package
(PSOP-8)
1
2
3
4
8
7
6
5
Figure 2. Pin Configuration of AP3581A/B/C (Top View)
Pin Description
Pin Number Pin Name Function
1 BOOT
Bootstrap pin. Connect a bootstrap capacitor (Typically from
0.1 µF to 0.47µF) from this pin to PHASE pin to create a BOOT
voltage suitable to drive a standard N-Channel MOSFET
2 UGATE
Upper-gate drive pin. Connect this pin to the upper MOSFET gate
providing the gate drive. This pin is monitored by the adaptive
shoot-through protection circuitry to determine when the upper
MOSFET has been turned off
3 OPS
Over-current setting pin. Connecting a resistor (R
OCSET
) between
OPS and GND to set the over-current trigger point
4 LGATE
Lower-gate drive pin. Connect LGATE to the lower MOSFET
gate providing the gate drive for the lower MOSFET. This pin is
monitored by the adaptive shoot-through protection circuitry to
determine when the lower MOSFET has turned off
5 VCC
Bias supply pin. Provides a 5V or 12V bias supply for the chip
from this pin. The pin should be bypassed with a capacitor to
GND
6 FB
Feedback pin. This pin is the inverting input of the internal error
amplifier. Use FB pin, in combination with the COMP pin, to
compensate the voltage control feedback loop of the converter. A
resistor divider from output to GND is used to set the output
voltage
7 COMP/EN
Compensation and disable pin, this pin is the output of the error
amplifier. Pull COMP pin low will shut down the IC
8 PHASE
PHASE pin. This pin connects to the source of the upper
MOSFET and the drain of the lower MOSFET. This pin is also
monitored by the adaptive shoot-through protection circuitry to
determine when the upper MOSFET has turned off
9 GND
Exposed pad as ground pin. Represents the signal and power
ground for the IC. Tie this pin to the ground island/plane through
the lowest impedance connection available