ISL6532C

The ISL6532C provides a complete ACPI compliant power solution for up to 4 DIMM dual channel DDR/DDR2 Memory systems. Included are both a synchronous buck controller and integrated LDO to supply V_DDQ with high current during S0/S1 states and standby current during S3 state. During S0/S1 state, a fully integrated sink-source regulator generates an accurate (V_DDQ /2) high current V_TT voltage without the need for a negative supply. A buffered version of the V_DDQ /2 reference is provided as V_REF. An LDO controller is also integrated for AGP core voltage regulation.

The switching PWM controller drives two N-Channel MOSFETs in a synchronous-rectified buck converter topology. The synchronous buck converter uses voltagemode control with fast transient response. Both the switching regulator and standby LDO provide a maximum static regulation tolerance of ±2% over line, load, and temperature ranges. The output is user-adjustable by means of external resistors down to 0.8V.

Switching memory core output between the PWM regulator and the standby LDO during state transitions is accomplished smoothly via the internal ACPI control circuitry. The NCH signal provides synchronized switching of a backfeed blocking switch during the transitions eliminating the need to route 5V Dual to the memory supply.

An integrated soft-start feature brings all outputs into regulation in a controlled manner when returning to S0/S1 state from any sleep state. During S0 the PGOOD signal indicates V_TT is within spec and operational.

Each output is monitored for under and over-voltage events. The switching regulator has over current protection. Thermal shutdown is integrated.