Diodes AP3585A/B/C - Manual (Page 2)

AP3585A/B/C
Document number: DS36819 Rev. 1 - 2
2 of 18
www.diodes.com
January 2014
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AP3585A/B/C
A Product Line of
Diodes Incorporated
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UC
T
Typical Applications Circuit
Pin Descriptions
Pin Number
Pin Name Function
SO-8 SO-8EP
1 1 BOOT
Bootstrap pin. Connect a bootstrap capacitor from this pin to PHASE for
creating a BOOT voltage suitable to drive a standard N-Channel
MOSFET.
2 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
turned off.
3 3 GND
Ground for the IC. All voltage levels are measured with respect to this pin.
Connect this pin directly to the low side MOSFET source and ground
plane with the lowest impedance. The exposed pad must be soldered to a
large PCB and connected to GND for maximum power dissipation.
4 4 LGATE/OCSET
Low-side Gate Driver Output and Over-Current Setting Input. This pin is
the gate driver for low-side MOSFET. It is also used to set the maximum
inductor current. Refer to the section in “Function Description” for detail.
5 5 VCC
Bias supply pin. Provides a 4.5V to 13.2V bias supply for the chip from this
pin. The pin should be bypassed with a capacitor to GND.
6 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 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 8 PHASE
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 Exposed Pad Exposed Pad as ground pin.