ISL6253 Datasheet, PDF (20/22 Pages) Intersil Corporation – Highly Integrated Battery Charger for Notebook Computers

ISL6253
PHASE PIN
This trace should be short, and positioned away from other
weak signal traces. This node has a very high dv/dt with a
voltage swing from the input voltage to ground. No trace
should be in parallel with it. This trace is also the return path
for UGATE. Connect this pin to the high-side MOSFET
source.
UGATE PIN
This pin has a square shape waveform with high dv/dt. It
provides the gate drive current to charge and discharges the
top MOSFET with high di/dt. This trace should be wide,
short, and away from other traces similar to the LGATE.
BOOT PIN
The BOOT pins di/dt is as high as the UGATE; therefore, this
trace should be as short as possible.
CSOP, CSON PINS
The current sense resistor connects to the CSON and the
CSOP pins through a low pass filter. The CSON pin is also
used as the battery voltage feedback. The traces should be
away from the high dv/dt and di/di pins like the PHASE and
BOOT pins. In general, the current sense resistor should be
close to the IC. Other layout arrangements should be
adjusted accordingly.
EN PIN
This pin stays high at enable mode and low at idle mode,
and is relatively robust. Enable signals should refer to the
signal ground.
DCIN PIN
This pin connects to AC adapter output voltage, and should
be less noise sensitive.
Copper Size for the Phase Node
The capacitance of PHASE should be kept very low to
minimize ringing. It would be best to limit the size of the
PHASE node copper in strict accordance with the current
and thermal management of the application.
Identify the Power and Signal Ground
The input and output capacitors of the converters, and the
source terminal of the bottom switching MOSFET PGND
should connect to the power ground. The other components
should connect to signal ground. Signal and power ground
are tied together at one point.
Clamping Capacitor for Switching MOSFET
It is recommended that ceramic caps be used closely
connected to the drain of the high-side MOSFET and the
source of the low-side MOSFET. This capacitor reduces the
noise and the power loss of the MOSFET.
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