ISL6527IBZ datasheet(5/17 Pages) RENESAS

5 / 17 page

ISL6527, ISL6527A

FN9056 Rev 11.00

Page 5 of 17

Sep 29, 2015

Functional Pin Description

14 LD (SOIC)

TOP VIEW

16 LD 5X5 (QFN)

TOP VIEW

VCC

This pin provides the bias supply for the ISL6527, ISL6527A.

Connect a well-decoupled 3.3V supply to this pin.

COMP and FB

COMP and FB are two of the three available external pins of

the error amplifier. The FB pin is the inverting input of the

internal error amplifier and the COMP pin is the error

amplifier output. These pins are used to compensate the

voltage-control feedback loop of the converter.

REF_IN

This pin is the third available external pin of the error

amplifier and represents the non-inverting input to the error

amplifier. Connect the desired reference voltage to this pin.

Voltage applied to this pin must not exceed 1.5V.

GND

This pin represents the signal and power ground for the IC.

Tie this pin to the ground island/plane through the lowest

impedance connection available.

PHASE

Connect this pin to the upper MOSFET’s source. This pin is

used to monitor the voltage drop across the upper MOSFET

for overcurrent protection.

UGATE

Connect this pin to the upper MOSFET’s gate. This pin

provides the PWM-controlled gate drive for the upper

MOSFET. This pin is also monitored by the adaptive

shoot-through protection circuitry to determine when the

upper MOSFET has turned off.

BOOT

This pin provides ground referenced bias voltage to the

upper MOSFET driver. A bootstrap circuit is used to create a

voltage suitable to drive a logic-level N-channel MOSFET.

LGATE

Connect this pin to the lower MOSFET’s gate. This pin

provides the PWM-controlled gate drive for the lower

MOSFET. This pin is also monitored by the adaptive

shoot-through protection circuitry to determine when the

lower MOSFET has turned off.

OCSET/SD

Connect a resistor (ROCSET) from this pin to the drain of the

upper MOSFET (VIN). ROCSET, an internal 20µA current

source (IOCSET), and the upper MOSFET ON-resistance

(rDS(ON)) set the converter overcurrent (OC) trip point

according to Equation 1:

An overcurrent trip cycles the soft-start function.

Pulling OCSET/SD to a voltage level below 0.8V disables

the controller. Disabling the ISL6527, ISL6527A causes the

oscillator to stop, the LGATE and UGATE outputs to be held

low, and the soft-start circuitry to re-arm.

CT1 and CT2

These pins are the connections for the external charge

pump capacitor. A minimum of a 0.1µF ceramic capacitor is

recommended for proper operation of the IC.

CPVOUT

This pin represents the output of the charge pump. The

voltage at this pin is the bias voltage for the IC. Connect a

decoupling capacitor from this pin to ground. The value of

the decoupling capacitor should be at least 10x the value of

the charge pump capacitor. This pin may be tied to the

bootstrap circuit as the source for creating the BOOT

voltage.

CPGND

This pin represents the signal and power ground for the

charge pump. Tie this pin to the ground island/plane through

the lowest impedance connection available.

LGATE

CPVOUT

UGATE

PHASE

VCC

BOOT

GND

CT1

CT2

OCSET/SD

CPGND

REF_IN

COMP

CPVOUT

CT1

CT2

OCSET/SD

PHASE

VCC

CPGND

IPEAK

IOCSETxROCSET

rDS ON



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(EQ. 1)

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