STMicroelectronics SRK2000A

Overview

SRK2000A from STMicroelectronics is a secondary-side synchronous rectifier smart driver IC optimized for LLC resonant converters with center-tapped transformer secondaries. It features dual N-channel MOSFET gate drivers (1 A source / 3.5 A sink), matched turn-off thresholds (±1 mV), intelligent automatic sleep mode, and operates from 4.5–32 V at up to 500 kHz - enabling high-efficiency AC-DC power supplies in server and industrial SMPS.

For engineers reviewing the SRK2000A datasheet, SRK2000A pinout, SRK2000A application, or SRK2000A equivalent, key selection criteria include drain-sensing threshold matching (-12 mV or -25 mV programmable), UVLO hysteresis (0.25 V), 250 µA quiescent current in active mode, and interlocked gate drive logic preventing simultaneous conduction in full-wave rectification topologies.

Technical Context

The SRK2000A implements a cycle-by-cycle, drain-voltage-sensing control scheme where each gate driver responds to negative-going edges on DVS1/DVS2 pins, triggering MOSFET turn-on when body diode conduction begins (VDVS_TH = −200 mV typ.) and turn-off when current approaches zero (programmable VDVS_Off = −12 mV or −25 mV). Interlocking logic ensures only one SR MOSFET conducts at a time.

Its intelligent sleep mode activates below light-load thresholds, halting gate driving and reducing quiescent consumption to 150 µA while maintaining fast wake-up response. The EN pin serves triple duty: setting turn-off thresholds, programming UVLO (VCC_On = 4.5 V, VCC_Off = 4.25 V), and enabling remote on/off control via 1.8 V comparator with 45 mV hysteresis.

Key Specifications

Pinout & Package

SRK2000A is housed in an SO-8 package with exposed thermal pad (package code: SO-8), optimized for surface-mount assembly and thermal dissipation in high-power density AC-DC converters.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous rectifier controller applications.

Compared with UCC24612-2 and MP6908A, the SRK2000A uniquely integrates dual interlocked drivers, sub-millivolt threshold matching, and intelligent sleep mode - making it the only solution qualified for high-reliability, high-efficiency center-tap LLC systems above 400 W.

Availability

SRK2000A is available at Aetrix Electronics and suitable for high-power AC-DC adapters, 90+/92+ compliant server SMPS, and industrial SMPS requiring stable component supply, long lifecycle support, and guaranteed traceable sourcing.

Supply support for SRK2000A 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, Switzerland, specializing in power management, analog, and microcontroller technologies for industrial, automotive, and consumer markets.

The SRK2000A belongs to ST's Synchronous Rectifier Controller product line, engineered specifically for high-frequency LLC resonant converters with center-tapped secondaries - targeting efficiency-critical server, computing, and industrial power supplies.

FAQ

What is the purpose of the EN pin on the SRK2000A?

The EN pin serves three critical functions: it programs the drain-sensing turn-off threshold (−12 mV or −25 mV), sets the UVLO turn-on/turn-off voltages (4.5 V / 4.25 V), and acts as an enable/disable input via a 1.8 V comparator with 45 mV hysteresis. Pulling EN below 1.75 V disables both gate drivers, allowing remote on/off control without interrupting VCC.

How does the SRK2000A prevent simultaneous conduction of both SR MOSFETs?

The SRK2000A uses hardware interlocking logic that monitors the state of both DVS inputs and enforces mutual exclusion: when GD1 is active, GD2 is forced low, and vice versa. This is implemented in the internal state machine and cannot be overridden by external signals - eliminating shoot-through risk in center-tap full-wave rectification.

Can the SRK2000A be used with standard-level (not logic-level) N-MOSFETs?

Yes - the SRK2000A's gate drivers deliver up to 12 V clamped high-level output, sufficient to fully enhance standard-threshold N-MOSFETs (V_GS(th) ≤ 4 V). Its 3.5 A sink current ensures rapid turn-off even with high gate charge devices, and the EN pin's resistor-divider configuration allows precise UVLO setting for optimal MOSFET biasing.

What design considerations apply to the DVS1 and DVS2 pins?

DVS1/DVS2 require external series resistors (typically 1–3 kΩ) to limit injected current during off-state voltage spikes - especially when V_DS exceeds 36 V. These resistors also set the effective turn-on threshold via Equation 6 (e.g., 2 kΩ yields −0.3 V). Layout must minimize trace inductance and avoid routing near switching nodes to preserve noise immunity and timing accuracy.