1

®

FN6494.0

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

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ISL6620, ISL6620A

VR11.1 Compatible Synchronous

Rectified Buck MOSFET Drivers

The ISL6620, ISL6620A is a high frequency MOSFET driver

designed to drive upper and lower power N-Channel

MOSFETs in a synchronous rectified buck converter topology.

The advanced PWM protocol of ISL6620, ISL6620A is

specifically designed to work with Intersil VR11.1 controllers

and combined with N-Channel MOSFETs, form a complete

core-voltage regulator solution for advanced microprocessors.

When ISL6620, ISL6620A detects a PSI protocol sent by an

Intersil VR11.1 controller, it activates Diode Emulation (DE)

operation; otherwise, it operates in normal Continuous

Conduction Mode (CCM) PWM mode.

The IC is biased by a single low voltage supply (5V),

minimizing driving losses in high MOSFET gate capacitance

and high switching frequency applications. Each driver is

capable of driving a 3nF load with less than 10ns rise/fall time.

Bootstrapping of the upper gate driver is implemented via an

internal low forward drop diode, reducing implementation cost,

complexity, and allowing the use of higher performance, cost

effective N-Channel MOSFETs.

To further enhance light load efficiency, ISL6620, ISL6620A

enables diode emulation operation during PSI mode. This

allows Discontinuous Conduction Mode (DCM) by detecting

when the inductor current reaches zero and subsequently

turning off the low side MOSFET to prevent it from sinking

current.

An advanced adaptive shoot-through protection is integrated

to prevent both the upper and lower MOSFETs from

conducting simultaneously and to minimize dead time. The

ISL6620, ISL6620A has a 20k

Ω integrated high-side

gate-to-source resistor to prevent self turn-on due to high

input bus dV/dt.

Features

• Dual MOSFET Drives for Synchronous Rectified Bridge

• Advanced Adaptive Zero Shoot-Through Protection

• 36V Internal Bootstrap Schottky Diode

• Advanced PWM Protocol (Patent Pending) to Support PSI

Mode, Diode Emulation, Three-State Operation

• Diode Emulation For Enhanced Light Load Efficiency

• Bootstrap Capacitor Overcharging Prevention

• Supports High Switching Frequency

- 4A Sinking Current Capability

- Fast Rise/Fall Times and Low Propagation Delays

• VCC Undervoltage Protection

• Enable Input and Power-On Reset

• Expandable Bottom Copper Pad for Enhanced Heat

Sinking

• DFN Package:

- Compliant to JEDEC PUB95 MO-220

DFN - Dual Flat No Leads - Package Outline

- Near Chip Scale Package Footprint, which Improves

PCB Efficiency and has a Thinner Profile

• Pb-Free (RoHS Compliant)

Applications

• High Light Load Efficiency Voltage Regulators

• Core Regulators for Advanced Microprocessors

• High Current DC/DC Converters

• High Frequency and High Efficiency VRM and VRD

Related Literature

• Technical Brief TB363 “Guidelines for Handling and

Processing Moisture Sensitive Surface Mount Devices

(SMDs)”

• Technical Brief TB417 “Designing Stable Compensation

Networks for Single Phase Voltage Mode Buck

Regulators” for Power Train Design, Layout Guidelines,

and Feedback Compensation Design

Data Sheet

April 25, 2008