ISL6540_06 Datasheet, PDF(15/20 Page) Intersil Corporation – Single-Phase Buck PWM Controller with Integrated High Speed MOSFET Driver and Pre-Biased Load Capability

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ISL6540_06 Datasheet, PDF (15/20 Pages) Intersil Corporation – Single-Phase Buck PWM Controller with Integrated High Speed MOSFET Driver and Pre-Biased Load Capability

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ISL6540

VOUT (LOCAL)

VSENSE- VSENSE+

(REMOTE) (REMOTE)

10â¦

GND (LOCAL) 10â¦

VCC

ROS

RFB

CSEN

VSEN-

VSEN+

ZIN

VMON

ZFB

COMP

800mV

GAIN=1

VSS

OV/UV

COMP

ERROR AMP

FIGURE 6. SIMPLIFIED UNITY GAIN DIFFERENITAL SENSING IMPLEMENTATION

Application Guidelines

Layout Considerations

As in any high frequency switching converter, layout is very

important. Switching current from one power device to

another can generate voltage transients across the

impedances of the interconnecting bond wires and circuit

traces. These interconnecting impedances should be

minimized by using wide, short printed circuit traces. The

critical components should be located as close together as

possible using ground plane construction or single point

grounding.

VIN

ISL6540

UGATE

PHASE

VOUT

LGATE

PGND

CIN

RETURN

part of ground or power plane in a printed circuit board. The

components shown in Figure 8 should be located as close

together as possible. Please note that the capacitors CIN

and CO each represent numerous physical capacitors.

Locate the ISL6540 within 3 inches of the MOSFETs, Q1

and Q2. The circuit traces for the MOSFETsâ gate and

source connections from the ISL6540 must be sized to

handle up to 4A peak current.

Proper grounding of the IC is important for correct operation

in noisy environments. The PGND pin should be connected

to board ground at the source of the low side MOSFET with

a wide short trace. The GND pin should be connected to a

large copper fill under the IC which is subsequently

connected to board ground at a quite location on the board,

typically found at an input or output bulk (electrolytic)

capacitor.

BOOT

CBOOT

ISL6540 PHASE

+5V

CSS

GND

PVCC

PGND

CPVCC

+VIN

Q1 LO

Q2 CO

VOUT

FIGURE 7. PRINTED CIRCUIT BOARD POWER AND

GROUND PLANES OR ISLANDS

Figure 7 shows the critical power components of the

converter. To minimize the voltage overshoot/undershoot

the interconnecting wires indicated by heavy lines should be

FIGURE 8. PRINTED CIRCUIT BOARD SMALL SIGNAL

LAYOUT GUIDELINES

FN9214.0

March 9, 2006

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