FAN5231 Datasheet, PDF (1/17 Pages) Fairchild Semiconductor – Precision Dual PWM Controller And Linear Regulator for Notebook CPUs

www.fairchildsemi.com
FAN5231
Precision Dual PWM Controller And Linear
Regulator for Notebook CPUs
Features
• Provides 3 Regulated Voltages
– Microprocessor core (SpeedStep™-enabled)
– Microprocessor I/O
– Microprocessor Clock Generator
• High Efficiency Over Wide Load Range
• Not Dissipative Current-Sense Scheme
– Uses MOSFET’s R _DS(ON)
– Optional Current-Sense Resistor for Precision
Overcurrent
• Adaptive Dead Time Drivers for N-Channel MOSFETs
• Operates from +5V, +3.3V and Battery (5.6-24V) Inputs
• Precision Core Voltage Control:
– Remote “Kelvin” Sensing
– Summing Current-Mode Control
– On-Chip Mode-Compensated “Droop” for Optimum
Transient Response and Lower Processor Power
Dissipation
• TTL-Compatible 5-Bit Digital Output Voltage Selection
– Wide Range - 0.925VDC to 1.3VDC in 25mV Steps,
and from 1.3VDC to 2.0VDC in 50mV Steps
– Programmable “On-the-Fly” VID code change with
customer programmable slew rate and 100ms settling
time
• Power-Good Output Voltage Monitor
• No negative Core and I/O voltage on turn-off
• Over-Voltage, Under-Voltage and Over-Current Fault
Monitors
• 300kHz Fixed Switching Frequency
• Thermal Shut-Down
Applications
• Converters for Mobile Dual-Mode CPUs
• Web Tablets
• Internet Appliances
+V_IN
V_OUT2
I/ O
+V_IN
3.3V
V_OUT3
CPU CLK
PWM 2
CONTROLLER
PWM 1
CONTROLLER
LI NEAR
REGULA T OR
VI D CODE
FAN5231
Figure 1. Simplified Power System Diagram
V_OUT1
CORE
REV. 1.1.1 8/15/01