Dual PWM Controller with DDR Memory Option for Gateway Applications

The ISL6444 PWM controller provides high efficiency and regulation for two output voltages adjustable in the range from 0.9V to 5.5V that are required to power I/O, chip-sets, and memory banks in high-performance notebook computers, PDAs, and Internet appliances.

Features
• Provides regulated output voltage in the range 0.9V to 5.5V
    - High efficiency over wide load range
    - Synchronous buck converter with hysteretic operation at light load
• Complete DDR memory power solution
    - VTT tracks VDDQ/2
    - VDDQ/2 buffered reference output
• No current-sense resistor required
    - Uses MOSFET’s rDS(ON)
    - Optional current-sense resistor for precision overcurrent
• Undervoltage lock-out on VCC pin
• Dual mode operation
    - Operates directly from battery 5.0V to 24V input
    - Operates from 3.3V or 5V system rail
• Excellent dynamic response
    - Combined voltage feed-forward and current mode control
• Power-good signal for each channel
• 300kHz switching frequency
    - Out-of-phase operation for reduced input ripple
    - In-phase operation in DDR mode for reduced channel interference
    - Out-of-phase operation with 90° phase shift for two-stage conversion in DDR mode
• Pb-free plus anneal available (RoHS compliant)

Applications
• Residential and Enterprise Gateways
• DSL Modems
• Routers and Switchers