STMicroelectronics SRK2001ATR

Overview

SRK2001ATR from STMicroelectronics is a secondary-side adaptive synchronous rectification controller optimized for LLC resonant converters with center-tapped secondary windings. It drives two N-channel MOSFETs independently, features dual Kelvin drain-source sensing (up to 90 V), adaptive turn-on masking (up to 10% of clock cycle), adaptive two-slope turn-off, and 50 μA quiescent current in low-consumption mode - enabling >92% efficiency in high-end server SMPS.

For engineers reviewing the SRK2001ATR datasheet, SRK2001ATR pinout, SRK2001ATR application, or SRK2001ATR equivalent, key selection criteria include its 4.5–32 V VCC range, 500 kHz max operating frequency, programmable burst-mode exit duty cycle via PROG pin, and interlocked dual gate drivers with 11 V clamped output voltage - all critical for zero-voltage switching (ZVS) preservation in high-density AC-DC power supplies.

Technical Context

The SRK2001ATR implements asynchronous digital state machines for independent control of two SR MOSFETs, with interlock logic preventing simultaneous conduction. Its drain-source sensing uses dedicated DVS/SVS pin pairs per channel with 100 Ω series resistors, enabling high-voltage Kelvin sensing referenced to local source nodes - essential for accurate body-diode conduction detection in transformer center-tap topologies.

Turn-off is managed by dual mechanisms: an adaptive algorithm that maximizes conduction time by dynamically adjusting blanking delay to minimize residual body-diode conduction (target T_diode ≤ 75 ns), and a self-adaptive ZCD_OFF comparator that triggers fast turn-off during transients or above-resonance operation - both coordinated without external compensation components.

Key Specifications

Pinout & Package

SRK2001ATR is housed in a 10-pin SSOP package (4.4 mm × 3.0 mm, 0.65 mm pitch) with exposed thermal pad for enhanced power dissipation (R_{th j-amb} = 130 °C/W with 25 mm² copper pour).

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC24612-2QDRQ1 and MP6908AGS-Z, the SRK2001ATR uniquely combines dual-channel adaptive turn-off, programmable burst-exit duty, and integrated ZCD_OFF protection - making it the only option capable of maintaining >92% efficiency across full load range in high-power server and industrial LLC SMPS without external compensation.

Availability

SRK2001ATR 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 lifecycle support, and guaranteed traceable sourcing.

Supply support for SRK2001ATR 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The SRK2001ATR belongs to ST's high-efficiency power conversion controller product line, engineered specifically to replace diode rectification in resonant topologies - with emphasis on LLC, soft-switching preservation, and ultra-low standby power.

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 caused by dV/dt on the drain node. This value is specified in ST's DS11726 Rev 5 (page 9) and ensures safe operation under worst-case transient conditions up to 90 V drain-source swing while maintaining sensing accuracy.

How does the adaptive turn-on masking time scale with load?

The masking time TD_On starts at 7% of the clock cycle at startup and adapts dynamically: minimum 100 ns at full load, increasing up to 10% of the clock period at light load. This prevents false triggering from capacitive currents while preserving ZVS - verified in Figure 7 of DS11726 Rev 5.

Can SRK2001ATR operate without a VCC supply after startup?

No. The device requires continuous VCC bias (4.5–32 V) during operation. DS11726 Rev 5 (page 9) explicitly states that floating VCC while DVS pins are switching is prohibited - due to risk of dV/dt-induced current damage to internal circuitry.

What is the maximum allowable stray inductance in the SR MOSFET source path?

Stray inductance must be minimized to ≤10 nH in the source path between SR MOSFET source and SVS pin, as confirmed by ST application note AN4777. Higher values degrade Kelvin sensing accuracy and cause premature turn-off - especially critical for the adaptive algorithm's residual conduction target (≤75 ns).