STMicroelectronics SRK2001

Overview

SRK2001 from STMicroelectronics is a secondary-side adaptive synchronous rectification controller optimized for LLC resonant converters with center-tapped secondary windings. It features dual N-channel MOSFET gate drivers, 35 ns total turn-off delay, 50 μA quiescent current in low-consumption mode, and Kelvin drain-source sensing per SR channel-enabling high-efficiency AC-DC power supplies in 92+ server SMPS and 85+ ATX designs.

For engineers reviewing the SRK2001 datasheet, SRK2001 pinout, SRK2001 application, or SRK2001 equivalent, key selection criteria include adaptive turn-on/off timing under varying load, programmable sleep-mode entry/exit thresholds, ZCD-based fast turn-off for current inversion protection, and SSOP10 package compatibility with high-density PCB layouts in resonant converter secondary-side implementations.

Technical Context

The SRK2001 implements an asynchronous logic-based control architecture with three interlocked state machines: two for independent SR gate drive sequencing and one for intelligent sleep-mode transitions. Its dual-channel operation relies on Kelvin-sensed DVS/SVS pairs to detect body-diode conduction onset (VTH_ON = −100 mV) and zero-current crossing via self-adaptive ZCD comparator blanked for 450 ns after turn-on.

Turn-on uses adaptive masking time (TD_On_min = 100 ns, up to 40% of clock period at light load) to suppress capacitive false triggering; turn-off combines two-slope adaptive algorithm (maximizing conduction time cycle-by-cycle) and ZCD-triggered fast shutdown (≤35 ns total delay) to prevent current reversal during fast transients or above-resonance operation.

Key Specifications

Pinout & Package

SRK2001 is housed in a thermally enhanced SSOP10 package with exposed thermal pad (pin 2 connected to GND plane), supporting 130 °C/W junction-to-ambient thermal resistance when mounted on 25 mm² copper area.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar secondary-side synchronous rectification applications.

Compared with UCC24612-2 and MP6908A, SRK2001 delivers superior light-load efficiency via programmable sleep mode, higher reliability through Kelvin-sensed ZCD protection, and simplified BOM with no external compensation components - making it optimal for 92+ server and high-end TV power supplies.

Availability

SRK2001 is available at Aetrix Electronics and suitable for AC-DC adapters, high-end flat panel TV power supplies, and 92+ compliant server SMPS requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and datacenter deployments.

Supply support for SRK2001 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power management, analog, and microcontroller solutions for industrial, automotive, and consumer markets.

The SRK2001 belongs to ST's high-efficiency power conversion controller product line, designed specifically to maximize LLC resonant converter efficiency through adaptive secondary-side synchronous rectification with integrated protection and programmable light-load behavior.

FAQ

What is the minimum recommended series resistor for DVS1/DVS2 pins?

A 100 Ω resistor is mandatory in series with each DVS pin to limit dynamic current injection and prevent damage from dV/dt-induced stress. This value is specified in the absolute maximum ratings table and validated across temperature and voltage extremes in DS10811 Rev 7. Omitting it risks latch-up or permanent failure during fast switching transitions.

How does the adaptive turn-on masking time improve efficiency at light load?

The adaptive masking time (TD_On) increases up to 40% of the clock period at light load to suppress false triggering from capacitive current spikes-not real body-diode conduction. This prevents premature MOSFET turn-on that would discharge the output capacitor and increase RMS current, directly preserving converter efficiency in standby and burst-mode operation.

Can SRK2001 operate without an auxiliary VCC supply?

Yes - SRK2001 is designed to be powered directly from the LLC output rail via the VCC pin (4.5–32 V range). No auxiliary winding or bias supply is needed, simplifying transformer design and reducing component count. Internal UVLO and 36 V clamp ensure safe startup and overvoltage protection without external circuitry.

What is the purpose of the PROG and EN pins sharing programming functionality?

Both PROG and EN pins use internal 10 μA current sources to set voltage thresholds that select predefined conduction duty cycles from internal lookup tables. PROG configures sleep-mode entry level during startup; EN sets burst-mode exit level and enables remote ON/OFF. This dual-role design reduces pin count while maintaining independent control of critical light-load behaviors.