ISL6208 Datasheet, PDF (1/11 Pages) Intersil Corporation – High Voltage Synchronous Rectified Buck MOSFET Driver

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Data Sheet
August 7, 2008
ISL6208
FN9115.3
High Voltage Synchronous Rectified Buck
MOSFET Driver
The ISL6208 is a high frequency, dual MOSFET driver,
optimized to drive two N-Channel power MOSFETs in a
synchronous-rectified buck converter topology. It is
especially suited for mobile computing applications that
require high efficiency and excellent thermal performance.
This driver, combined with an Intersil multiphase Buck PWM
controller, forms a complete single-stage core-voltage
regulator solution for advanced mobile microprocessors.
The ISL6208 features 4A typical sinking current for the lower
gate driver. This current is capable of holding the lower
MOSFET gate off during the rising edge of the Phase node.
This prevents shoot-through power loss caused by the high
dv/dt of phase voltages. The operating voltage matches the
30V breakdown voltage of the MOSFETs commonly used in
mobile computer power supplies.
The ISL6208 also features a three-state PWM input that,
working together with Intersil’s multiphase PWM controllers,
will prevent negative voltage output during CPU shutdown.
This feature eliminates a protective Schottky diode usually
seen in a microprocessor power systems.
MOSFET gates can be efficiently switched up to 2MHz using
the ISL6208. Each driver is capable of driving a 3000pF load
with propagation delays of 8ns and transition times under
10ns. Bootstrapping is implemented with an internal
Schottky diode. This reduces system cost and complexity,
while allowing the use of higher performance MOSFETs.
Adaptive shoot-through protection is integrated to prevent
both MOSFETs from conducting simultaneously.
A diode emulation feature is integrated in the ISL6208 to
enhance converter efficiency at light load conditions. This
feature also allows for monotonic start-up into pre-biased
outputs. When diode emulation is enabled, the driver will
allow discontinuous conduction mode by detecting when the
inductor current reaches zero and subsequently turning off
the low side MOSFET gate.
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 and fall time
- 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 Start-Up Applications
• VCC POR (Power-On-Reset) Feature Integrated
• Low Three-State Shutdown Holdoff Time (Typical 160ns)
• Pin-to-Pin Compatible with ISL6207
• 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 (RoHS compliant)
Applications
• Core Voltage Supplies for Intel® and AMD® Mobile
Microprocessors
• High Frequency Low Profile DC/DC Converters
• High Current Low Output Voltage DC/DC Converters
• High Input Voltage DC/DC Converters
Related Literature
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
(SMDs)”
• Technical Brief TB389 “PCB Land Pattern Design and
Surface Mount Guidelines for MLFP Packages”
• Technical Brief TB447 “Guidelines for Preventing
Boot-to-Phase Stress on Half-Bridge MOSFET Driver ICs”
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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