ISL6554

Features:

* Multi-Phase Power Conversion
* Precision Channel Current Balance
- Lossless Current Sampling - Uses rDS(ON)
* Precision CORE Voltage Regulation
- ±1% System Accuracy Over Temperature
- No Programmable Droop
* Microprocessor Voltage Identification Input
- 5-Bit VID Decoder
- 0.95V to 1.70V in 25mV Steps
* Fast Transient Response
* Overcurrent Protection
* Selection of 2, 3, or 4 Phase Operation
* High Ripple Frequency (80kHz to 2MHz)
* Pb-Free Available (RoHS Compliant)




Application

* Power Supply Controller for Intel(R) Itanium(TM) Processor Family
* Voltage Regulator Modules
* Servers and Workstations




Pinout






Specifications

Supply Voltage, VCC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+7V
Input, Output, or I/O Voltage . . . . . . . . . . GND -0.3V to VCC + 0.3V
ESD Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5KV




Description

The ISL6554 is the first controller in the Intersil Multi-Phase family without the programmable droop feature. The ISL6554 in combination with the HIP6601A, HIP6602A or HIP6603A companion gate drivers and Intersil MOSFETs form a complete solution for high-current, high slew-rate applications. The ISL6554 regulates output voltage, balances load currents and provides protective functions for two to four synchronous-rectified buck-converter channels.

A novel approach to current sensing is used to reduce overall solution cost. The voltage developed across the lower MOSFET's parasitic on-resistance during conduction is sampled and fed back to the controller. This lossless current-sensing approach allows the controller to maintain phase-current balance between the power channels and overcurrent protection.

A 5-bit DAC ISL6554 allows digital programming of the output voltage in 25mV steps over a range from 0.95V to 1.70V with a system accuracy of ±1%. Internal pull ups on each DAC input make external pull-up resistors unnecessary when interfacing with open-drain output signals.

The PGOOD signal ISL6554 is held low during soft-start until the output voltage increases to within 4% of the programmed. When the CORE voltage falls 9% below the programmed VID level, an undervoltage condition is detected and results in PGOOD transitioning low.

In the event of an overvoltage condition, The converter ISL6554 shuts down and turns ON the lower MOSFETs to clamp and protect the microprocessor. Overcurrent protection reduces the regulator RMS output current to 41% of the programmed overcurrent trip value. These features of ISL6554 provide monitoring and protection for the microprocessor and power system.