SC2422A

Features:

• Precision, pulse by pulse phase current matching
• Active drooping allows for best transient response
• Input Sensing Current mode control
• Programmable DAC step size/offset allows Compliance with VRM9.0, VRM8.3 or VRM8.4
• Externally programmable soft-start
• 5V or 12V input for next generation processors
• 0% minimum duty cycle improves transient response
• Externally Programmable UVLO with hysteresis
• Cycle by cycle current limiting
• Programmable Internal Oscillator to 1 MHz
• VID IIIII Inhibit (No CPU)


Application

• Intel Advanced Microprocessors
• AMD Athlon^TM power supplies
• Servers/Workstations, high density power supplies


Pinout




Specifications

Parameter	Symbol	Maximum	Units
Input DC Rail Voltage to GND	VIN	15	V
PGND to GND		+ 1	V
Operating Temperature Range	TA	-20 to 125	°C
Junction Temperature	TJ	0 to 125	°C
Thermal Resistance Junction to Case	JC	20	°C/W
Thermal Resistance Junction to Ambient	JA	60	°C/W
Storage Temperature Range	TSTG	-65 to +150	°C
Lead Temperature (Soldering) 10 sec	TLEAD	300	°C

Description

The SC2422A biphase, current mode controller is designed to work with Semtech smart synchronous drivers, such as the SC1205, SC1305 or the SC1405 to provide the DC/DC converter solution for the most demanding Micro-processor applications. Input current rather than output current sensing is used to guarantee precision phase to phase current matching using a single sense resistor on the input power line. Accurate current sharing and pulse by pulse current limit are implemented without the power loss and transient response degradation associated with output current sense methods. Two phase operation allows significant reduction in input/output ripple while enhancing transient response.

The DAC step size and range are programmable with external components thus allowing compliance with new and emerging VID ranges.

A novel approach implements active droop, minimizing output capacitor requirements during load transients. This avoids the pitfalls of the passive droop implementation. This feature also allows easy implementation of N+1 redundancy and current sharing among modules.

Programmable Under Voltage Lockout assures proper start-up and shutdown by synchronizing the controller to the driver supply. Wide PWM frequency range allows use of low profile, surface mount components.