ISL6556A
Optimized Multiphase PWM Controller with 6-Bit DAC for VR10.X Application
Key Features
- Precision Multi-Phase Core Voltage Regulation
- Differential Remote Voltage Sensing
- ±0.5% System Accuracy Over Temperature and Life
- Adjustable Reference-Voltage Offset
- Precision rDS(ON) Current Sensing
- Accurate Load-Line Programming
- Accurate Channel-Current Balancing
- Low-Cost, Lossless Current Sensing
- Internal Shunt Regulator for 5V or 12V Biasing
- Microprocessor Voltage Identification Input
- Dynamic VID™ Technology
- 6-Bit VID Input
- 0.8375V to 1.600V in 12.5mV Steps
- Threshold Enable Function for Precision Sequencing
- Overcurrent Protection
- Overvoltage Protection
- No Additional External Components Needed
- OVP Pin to drive optional Crowbar Device
- 2, 3, or 4 Phase Operation up to 1.5MHz per Phase
- QFN Package Option
- QFN Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat No Leads - Product Outline
- QFN Near Chip Scale Package Footprint; Improves PCB Efficiency, Thinner in Profile
- Pb-free Available (RoHS Compliant)
Description
The ISL6556A controls microprocessor core voltage regulation by driving up to 4 synchronous-rectified buck channels in parallel. Multi-phase buck converter architecture uses interleaved timing to multiply channel ripple frequency and reduce input and output ripple currents. Lower ripple results in fewer components, lower component cost, reduced power dissipation, and smaller implementation area.
The ISL6556A utilizes rDS(ON) current sensing in each phase for adaptive voltage positioning (droop), channelcurrent balancing, and overcurrent protection. To ensure droop accuracy, an external NTC compensation circuit can be used to completely nullify the effect of temperature related variation in rDS(ON).
A unity gain, differential amplifier is provided for remote voltage sensing. Any potential difference between remote and local grounds can be eliminated using the remote-sense amplifier. The precision threshold-sensitive enable input is available to accurately coordinate the start up of the ISL6556A with Intersil MOSFET driver IC. Dynamic-VID™ technology allows seamless on-the-fly VID changes. The offset pin allows accurate voltage offset settings that are independent of VID setting. The ISL6556A uses 5V bias and has a built-in shunt regulator to allow 12V bias using only a small external limiting resistor.
