intersil ISL6608 DATA SHEET

®

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ISL6608

Data Sheet March 2004 FN9140.1

Synchronous Rectified MOSFET Driver
with Pre-Biased Load Startup Capability

The ISL6608 is a high frequency, MOSFET driver optimized
to drive two N-Channel power MOSFETs in a synchronous­rectified buck converter topology. This driver combined with
an Intersil HIP63xx or ISL65xx Multi-Phase Buck PWM
controller forms a complete single-stage core-voltage
regulator solution with high efficiency performance at high
switching frequency for advanced microprocessors.

The IC is biased by a single low voltage supply (5V) and
minimizes gate drive losses due to MOSFET gate charge at
high switching frequency applications. Each driver is capable
of driving a 3000pF load with a low propagation delay and
less than 10ns transition time. This product implements
bootstrapping on the upper gate with an internal bootstrap
Schottky diode, reducing implementation cost, complexity,
and allowing the use of higher performance, cost effective
N-Channel MOSFETs. Adaptive shoot-through protection is
integrated to prevent both MOSFETs from conducting
simultaneously.

The ISL6608 features 4A sink current for the lower gate
driver, which is capable of holding the lower MOSFET gate
during the Phase node rising edge to prevent shoot-through
power loss caused by the high dv/dt of the Phase node.

Features

• Dual MOSFET Drives for Synchronous Rectified Bridge

• Adaptive Shoot-Through Protection

•0.5Ω On-Resistance and 4A Sink Current Capability

• Supports High Switching Frequency up to 2MHz

- Fast Output Rise/Fall Time and Low Propagation Delay

• Three-State PWM Input for Power Stage Shutdown

• Internal Bootstrap Schottky Diode

• Low Bias Supply Current (5V, 80µA)

• Diode Emulation for Enhanced Light Load Efficiency and
Pre-Biased Startup Applications

• VCC POR (Power-On-Reset) Feature Integrated

• Low Three-State Shutdown Holdoff Time (Typically 160ns)

• Pin-to-Pin Compatible with ISL6605

• QFN Package:

- Compliant to JEDEC PUB95 MO-220

QFN - Quad Flat No Leads - Package Outline

- Near Chip Scale Package footprint, which improves

PCB efficiency and has a thinner profile

• Pb-free Available as an Option

The ISL6608 also features a Three-State PWM input which,
working together with Intersil multi-phase PWM controllers,
will prevent a negative transient on the output voltage when
the output is shut down. This feature eliminates the Schottky
diode that is usually seen in a microprocessor power system
for protecting the microprocessor from reversed output
voltage events.

A diode emulation feature is integrated in the ISL6608 to
enhance converter efficiency at light load conditions. Diode
emulation also prevents a negative transient when starting
up with a pre-biased voltage on the output. When diode
emulation is enabled, the driver allows discontinuous
conduction mode by detecting when the inductor current
reaches zero and subsequently turns off the low side
MOSFET, which prevents the output from sinking current
and producing a negative transient on a pre-biased output
(see Figures 6 and 7 on page 7).

Applications

• Core Voltage Supplies for FPGAs and PowerPC
Microprocessors

• Point-Of-Load Modules with Pre-Biased Start-Up
Requirements

• High Frequency and High Current DC-DC Converters

Related Literature

• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices”

1

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 321-724-7143

| Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

Copyright © Intersil Americas Inc. 2004. All Rights Reserved

ISL6608

www.BDTIC.com/Intersil

Ordering Information

TEMP RANGE

PART NUMBER

ISL6608CB 0 to 70 8 Ld SOIC M8.15

ISL6608CB-T 8 Ld SOIC Tape and Reel

ISL6608CR 0 to 70 8 Ld 3x3 QFN L8.3x3

ISL6608CR-T 8 Ld 3x3 QFN Tape and Reel

ISL6608CBZ (Note) 0 to 70 8 Ld SOIC

ISL6608CBZ-T 8 Ld SOIC Tape and Reel (Lead-Free)

ISL6608CRZ (Note) 0 to 70 8 Ld 3x3 QFN

ISL6608CRZ-T 8 Ld 3x3 QFN Tape and Reel (Lead-Free)

ISL6608IB -40 to 85 8 Ld SOIC M8.15

ISL6608IB-T 8 Ld SOIC Tape and Reel

ISL6608IR -40 to 85 8 Ld 3x3 QFN L8.3x3

(°C) PACKAGE

(Lead-Free)

(Lead-Free)

PKG.

DWG. #

M8.15

L8.3x3

Pinouts

ISL6608CB (SOIC)

TOP VIEW

Ordering Information (Continued)

TEMP RANGE

PART NUMBER

ISL6608IR-T 8 Ld 3x3 QFN Tape and Reel

ISL6608IBZ (Note) -40 to 85 8 Ld SOIC

ISL6608IBZ-T (Note) 8 Ld SOIC Tape and Reel (Lead-Free)

ISL6608IRZ (Note) -40 to 85 8 Ld 3x3 QFN

ISL6608IRZ-T (Note) 8 Ld 3x3 QFN Tape and Reel (Lead-Free)

NOTE: Intersil Lead-Free products employ special lead-free
material sets; molding compounds/die attach materials and 100%
matte tin plate termination finish, which is compatible with both SnPb
and lead-free soldering operations. Intersil Lead-Free products are
MSL classified at lead-free peak reflow temperatures that meet or
exceed the lead-free requirements of IPC/JEDEC J Std-020B.

ISL6608CR (3X3 QFN)

(°C) PACKAGE

(Lead-Free)

(Lead-Free)

TOP VIEW

PKG.

DWG. #

M8.15

L8.3x3

UGATE

BOOT

PWM

GND

1

2

3

4

8

7

6

5

PHASE

FCCM

VCC

LGATE

BOOT

PWM

UGATE

PHASE

7

8

1

2

GND

6

FCCM

6

VCC

5

43

LGATE

2

Block Diagram

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ISL6608

ISL6608

VCC

FCCM

PWM

10K

CONTROL

LOGIC

SHOOT-

THROUGH

PROTECTION

VCC

THERMAL PAD (FOR QFN PACKAGE ONLY)

BOOT

UGATE

PHASE

LGATE

GND

Typical Application - Multi-Phase Converter Using ISL6608 Gate Drivers

V

BAT

+5V

+5V

PGOOD

VID

+5V

FB

VSEN

CONTROL

VCC

MAIN

COMP

PWM1

PWM2

FCCM

ISEN1

ISEN2

VCC

FCCM

PWM

THERMAL
PAD

+5V

DRIVE

ISL6608

BOOT

UGATE

PHASE

LGATE

V

BAT

+V

CORE

FS

DACOUT

GND

VCC

FCCM

PWM

THERMAL
PAD

DRIVE

ISL6608

BOOT

UGATE

PHASE

LGATE

3

ISL6608

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ti

Absolute Maximum Ratings Thermal Information

Supply Voltage (VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V

BOOT Voltage (V
Phase Voltage (V

Input Voltage (V

UGATE. . . . . . . . . . . . . . . . . . . . . . V

LGATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VCC + 0.3V

Ambient Temperature Range . . . . . . . . . . . . . . . . . . . -40°C to 125°C

). . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 22V

BOOT
PHASE

, V

DE

) (Note 1). . . V

). . . . . . . . . . . . . . . -0.3V to VCC + 0.3V

PWM

PHASE

BOOT

- 0.3V to V

- 7V to V

BOOT

BOOT

+ 0.3V

+ 0.3V

Thermal Resistance (Typical, Notes 2, 3, 4) θ

SOIC Package (Note 2) . . . . . . . . . . . . 110 n/a

QFN Package (Notes 3, 4). . . . . . . . . . 82 16

Maximum Junction Temperature (Plastic Package) . . . . . . . . 150°C

Maximum Storage Temperature Range. . . . . . . . . . . -65°C to 150°C

Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300°C

(SOIC - Lead Tips Only)

Recommended Operating Conditions

Ambient Temperature Range . . . . . . . . . . . . . . . . . . . .-40°C to 85°C

Maximum Operating Junction Temperature. . . . . . . . . . . . . . 125°C

Supply Voltage, VCC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5V ±10%

CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.

NOTES:

1. The Phase Voltage is capable of withstanding -7V when the BOOT pin is at GND.

is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.

2. θ

JA

3. θ

is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See

JA

Tech Brief TB379.

4. For θ

5. Guaranteed by design, not tested.

, the “case temp” location is the center of the exposed metal pad on the package underside.

JC

(°C/W) θJC (°C/W)

JA

Electrical Specifications Recommended Operating Conditions, Unless Otherwise Noted

PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS

VCC SUPPLY CURRENT

Bias Supply Current I

POWER-ON RESET (POR)

VCC Rising - 3.40 4.00 V

VCC Falling T

Hysteresis - 500 - mV

BOOTSTRAP DIODE

Forward Voltage V

PWM INPUT

Input Current I

PWM Three-State Rising Threshold V

PWM Three-State Falling Threshold V

Three-State Shutdown Holdoff Time t

FORCED CONTINUOUS CONDUCTION MODE (FCCM) INPUT

FCCM LOW Threshold 0.50 - - V

FCCM HIGH Threshold T

VCC

PWM

TSSHD

PWM Pin Floating, V

A

T

A

V

F

V

V

V

V

V

V

A

T

A

VCC

PWM

PWM

VCC

VCC

VCC

VCC

VCC

VCC

= 0°C to 70°C 2.40 2.90 - V

= -40°C to 85°C 2.175 2.90 - V

= 5V, IF = 2mA 0.40 0.52 0.62 V

= 5V - 250 - µA

= 0V - -250 - µA

= 5V 0.80 1.00 1.20 V

= 5V, TA = 0°C to 70°C 3.40 3.65 3.90 V

= 5V, TA = -40°C to 85°C 3.05 3.65 4.10 V

= 5.5V - - 4.55 V

= 5V, TA = 0°C to 70°C 100 160 250 ns

= 5V, TA = -40°C to 85°C 80 160 250 ns

= 0°C to 70°C - - 2.00 V

= -40°C to 85°C - - 2.05 V

= 5V - 80 - µA

VCC

4