ISL6263D Datasheet, PDF (8/17 Pages) Intersil Corporation – Pre-biased Output Start-Up Capability

ISL6263D
Functional Pin Descriptions
RBIAS (Pin 1) - Sets the internal 10µA current reference.
Connect a 150kΩ±1%resistor from RBIAS to VSS.
SOFT (Pin 2) - Sets the output voltage slew-rate. Connect
an X5R or X7R ceramic capacitor from SOFT to VSS. The
SOFT pin is the non-inverting input of the error amplifier.
OCSET (Pin 3) - Sets the overcurrent threshold. Connect a
resistor from OCSET to VO.
VW (Pin 4) - Sets the static PWM switching frequency in
continuous conduction mode. Connect a resistor from VW to
COMP.
COMP (Pin 5) - Connects to the output of the control loop
error amplifier.
FB (Pin 6) - Connects to the inverting input of the control
loop error amplifier.
VDIFF (Pin 7) - Connects to the output of the VDIFF
differential amplifier. Together with FB pin, used for the
output voltage feedback.
VSEN (Pin 8) - This is the V_OUT input of the GPU processor
Kelvin connection. Connects internally to the non-inverting
inputs of the VDIFF differential amplifier.
RTN (Pin 9) - This is the V_GND input of the GPU processor
Kelvin connection. Connects internally to the inverting inputs
of the VDIFF differential amplifier.
ICOMP (Pin 10) - Connects to the output of the differential
current sense amplifier and to the non-inverting inputs of the
overcurrent comparator. Used for output current monitor and
overcurrent protection.
ISN (Pin 11) - This is the feedback of the current sense
amplifier. Connects internally to the inverting input of the
current sense amplifier. Used for output current sense.
VO (Pin 12) - Connects to the inverting inputs of the VDIFF
differential amplifier. Measures the output voltage V_OUT.
ISP (Pin 13) - Connects to the non-inverting input of the
current sense amplifier. Used for output current sense.
VIN (Pin 14) - Connects to the R³ PWM modulator providing
input voltage feed-forward. For optimum input voltage
transient response, connect near the drain of the high-side
MOSFETs.
VSS (Pin 15) - Analog ground.
VDD (Pin 16) - Input power supply for the IC. Connect to
+5VDC and decouple with at least a 1µF MLCC capacitor
from the VDD pin to the VSS pin.
BOOT (Pin 17) - Input power supply for the high-side
MOSFET gate driver. Connect an MLCC bootstrap capacitor
from the BOOT pin to the PHASE pin.
UGATE (Pin 18) - High-side MOSFET gate driver output.
Connect to the gate of the high-side MOSFET.
PHASE (Pin 19) - Current return path for the UGATE
high-side MOSFET gate driver. Detects the polarity of the
PHASE node voltage for diode emulation. Connect the
PHASE pin to the drains of the low-side MOSFETs.
PGND (Pin 20) - Current return path for the LGATE low-side
MOSFET gate driver. The PGND pin only conducts current
when LGATE pulls down. Connect the PGND pin to the
sources of the low-side MOSFETs.
LGATE (Pin 21) - Low-side MOSFET gate driver output.
Connect to the gate of the low-side MOSFET.
PVCC (Pin 22) - Input power supply for the low-side
MOSFET gate driver, and the high-side MOSFET gate
driver, via the internal bootstrap diode connected between
the PVCC and BOOT pins. Connect to +5VDC and decouple
with at least 1µF of an MLCC capacitor from the PVCC pin to
the PGND pin.
OFFSET0 (Pin 23) - A logic high signal will incrementally
provide 12.5mV offset for the DAC output voltage. OFFSET0
pin should not be floated.
OFFSET1 (Pin 24) - A logic high signal will incrementally
provide 25mV offset for the DAC output voltage. OFFSET1
pin should not be floated.
VID0:VID2 (Pin 25:Pin 27) - Voltage identification inputs.
VID0 input is the least significant bit (LSB) and VID2 input is
the most significant bit (MSB).
IMON (Pin 28) - A voltage signal proportional to the output
current of the converter.
VR_ON (Pin 29) - A high logic signal on this pin enables the
converter and a low logic signal disables the converter.
AF_EN (Pin 30) - Together with FDE pin, used to program
the diode-emulation and audio filter behavior.
PGOOD (Pin 31) - The PGOOD pin is an open-drain output
that indicates when the converter is able to supply regulated
voltage. Connect the PGOOD pin to a maximum of 5V
through a pull-up resistor.
FDE (Pin 32) - Together with AF_EN pin, the FDE pin is
used to program the diode-emulation and audio filter
behavior.
BOTTOM - Connects to substrate. Electrically isolated but
should be connected to VSS. Requires best practical
thermal coupling to PCB.
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FN6753.1
July 8, 2010