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The ISL6608 is a high frequency, MOSFET driver optimized to drive two N-Channel power MOSFETs in a synchronous-rectified buck converter topology. This driver combined with an Intersil HIP63xx or ISL65xx Multiphase 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.

The ISL6608 also features a Three-State PWM input which, working together with Intersil Multiphase 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).

Key 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

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