VR13 controller for Intel server rails
The TPS53659RSBT is a dual-output voltage regulator controller from Texas Instruments' D-CAP+™ family, purpose-built for Intel VR13 processor power delivery. It integrates two independent output stages, each with its own feedback loop, to supply the core and graphics rails from a single 4.5V to 17V input bus. Output voltage range spans 0.25V to 1.52V on one channel and 0.5V to 2.8125V on the other, covering the sub-1V core and 1.8V/2.5V auxiliary rails common in VR13-compliant motherboards.
The 4.5V minimum input means the controller starts from a 5V standby rail or a 12V rail that has sagged during a transient — it does not require a separate bias supply. The 17V maximum covers the 12V nominal bus with margin for ripple, but not a 24V backplane; keep the input below 17V absolute. The 125°C junction rating is the ceiling — derating the output current above 85°C ambient is necessary to stay inside the SOA. The 40-WFQFN exposed-pad package (5x5 mm body) requires a thermal land on the PCB to pull heat from the die. The exposed pad is the primary thermal path — a via array under the pad to an inner ground plane is expected for full current delivery.