isl6228 Intersil Corporation, isl6228 Datasheet - Page 6

• Manufacturer Part Number: isl6228
• Description: High-performance Dual-output Buck Controller For Notebook Applications
• Manufacturer: Intersil Corporation

Functional Pin Descriptions
GND (Bottom Pad)
Signal common of the IC. Unless otherwise stated, signals
are referenced to the GND pin.
FSET2 (Pin 1)
The FSET2 pin programs the PWM switching frequency of
Channel 2. Program the desired PWM frequency with a
resistor and a capacitor connected across the FSET2 and
GND pins.
VIN2 (Pin 2)
The VIN2 pin measures the input voltage of the Channel 2
converter. It is a required input to the Channel 2 R
modulator. Connect the VIN2 pin to the drain of the
Channel 2 high-side MOSFET.
VCC2 (Pin 3)
The VCC2 pin is the input bias voltage for Channel 2.
Connect +5V to the VCC2 pin. Decouple with at least 1µF of
a MLCC capacitor from the VCC2 pin to the GND pin.
VCC1 (Pin 4)
The VCC1 pin is the input bias voltage for Channel 1.
Connect +5V to the VCC1 pin. Decouple with at least 1µF of
a MLCC capacitor from the VCC1 pin to the GND pin.
VIN1 (Pin 5)
The VIN1 pin measures the input voltage of the Channel 1
converter. It is a required input to the Channel 1 R
modulator. Connect the VIN1 pin to the drain of the
Channel 1 high-side MOSFET.
FSET1 (Pin 6)
The FSET1 pin programs the PWM switching frequency of
Channel 1. Program the desired PWM frequency with a
resistor and a capacitor connected across the FSET1 and
GND pins.
PGOOD1 (Pin 7)
The PGOOD1 pin is an open-drain output that indicates
when the Channel 1 converter is able to supply regulated
voltage. Connect the PGOOD1 pin to +5V through a pull-up
resistor.
FB1 (Pin 8)
The FB1 pin is the inverting input of the control-loop error
amplifier for Channel 1. The Channel 1 converter output
voltage regulates to 600mV from the FB1 pin to the GND pin.
Program the desired output voltage with a resistor network
connected across the VO1, FB1, and GND pins. Select the
resistor values such that FB1 to GND is 600mV when the
converter output voltage is at the programmed regulation
value.
6
3
3
PWM
PWM
ISL6228
VO1 (Pin 9)
The VO1 pin measures the Channel 1 converter output
voltage and is used as an input to the Channel 1 R
modulator. It also serves as part of Channel 1 inductor
current sensing and the OCP overcurrent fault protection
circuit.
OCSET1 (Pin 10)
The OCSET1 pin measures the Channel 1 inductor current
and programs the threshold of the OCP overcurrent fault
protection.
EN1 (Pin 11)
The EN1 pin is the on/off switch of Channel 1. The soft-start
sequence begins when the EN1 pin is pulled above the
rising threshold voltage V
power-on reset (POR) rising threshold voltage
When the EN1 pin is pulled below the falling threshold
voltage V
PHASE1 (Pin 12)
The PHASE1 pin is the current return path for the Channel 1
high-side MOSFET gate driver. Connect the PHASE1 pin to
the node consisting of the high-side MOSFET source, the
low-side MOSFET drain, and the output inductor of the
Channel 1 converter.
UGATE1 (Pin 13)
The UGATE1 pin is the output of the Channel 1 high-side
MOSFET gate driver. Connect the UGATE1 pin to the gate
of the Channel 1 converter high-side MOSFET.
BOOT1 (Pin 14)
The BOOT1 pin stores the input voltage for the Channel 1
high-side MOSFET gate driver. Connect an MLCC capacitor
across the BOOT1 and PHASE1 pins. The boot capacitor is
charged through an internal boot diode connected from the
PVCC1 pin to the BOOT1 pin, each time the PHASE1 pin
drops below PVCC1 minus the voltage dropped across the
internal boot diode.
PVCC1 (Pin 15)
The PVCC1 pin is the input voltage bias for the Channel 1
low-side MOSFET gate drivers. Connect +5V to the PVCC1
pin. Decouple with at least 1µF of an MLCC capacitor across
the PVCC1 and PGND1 pin.
LGATE1 (Pin 16)
The LGATE1 pin is the output of the Channel 1 converter
low-side MOSFET gate driver. Connect the LGATE1 pin to
the gate of the Channel 1 converter low-side MOSFET.
PGND1 (Pin 17)
The PGND1 pin is the current return path for the Channel 1
converter low-side MOSFET gate driver. Connect the
PGND1 pin to the source of the Channel 1 converter low-
side MOSFET through a low impedance path, preferably in
ENTHF
PWM1 immediately stops.
ENTHR
and VCC1 is above the
V VCC_THR
August 27, 2007
3
PWM
FN9095.1
.