STMicroelectronics STSR2PCD

Overview

STSR2PCD from STMicroelectronics is a dual-channel synchronous rectifier smart driver IC for forward converter secondary-side MOSFET control. It delivers complementary gate drive outputs with programmable turn-off anticipation (75–225 ns), operates from 4.5–5.5 V supply, supports 20–750 kHz switching, and integrates UVLO, inhibit-controlled discontinuous mode, and shoot-through prevention logic.

For engineers reviewing the STSR2PCD datasheet, STSR2PCD pinout, STSR2PCD application, or STSR2PCD equivalent, this device is selected for high-efficiency, low-voltage DC-DC conversion where precise timing control of synchronous rectifiers, duty-cycle adaptive shutdown (<13%), and magnetic reset independence are critical design requirements.

Technical Context

The STSR2PCD implements cycle-by-cycle dead-time control using a synchronized 15 MHz internal oscillator to generate self-adjusting turn-off anticipation on both OUTGATE1 and OUTGATE2. Its clock input (CK) uses a fixed 2.6–2.8 V threshold with ±600 µA leakage, enabling robust synchronization across variable demagnetization waveforms.

Turn-off timing is decoupled from forward transformer reset technique: OUTGATE1 anticipates CK falling edge by fixed 75 ns, while OUTGATE2 anticipation (75/150/225 ns) is set via external voltage divider on SETANT2. The INHIBIT pin enables freewheeling MOSFET shutdown during reverse current, supporting true discontinuous conduction mode.

Key Specifications

Pinout & Package

STSR2PCD is housed in an SO-8 package (5.0 × 4.0 mm body, 1.27 mm pitch) with thermally enhanced layout separating SGLGND (control ground) from PWRGND (power return) to suppress noise coupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IR11672PbF and UCC24612DR, STSR2PCD uniquely provides dual-channel, clock-synchronized, programmable anticipation, and hardware-enforced DCM - making it the only option for precision-timed, two-MOSFET forward converter secondaries requiring magnetic reset independence.

Availability

STSR2PCD is available at Aetrix Electronics and suitable for telecom power supplies, industrial DC-DC modules, and server VRMs requiring stable component supply, long-lifecycle availability, and consistent timing performance across temperature and voltage variation.

Supply support for STSR2PCD 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 STSR2P product line targets high-efficiency AC-DC and isolated DC-DC converters, specifically engineered to replace Schottky diodes in forward, half-bridge, and active-clamp topologies through intelligent, timing-accurate synchronous rectification.

FAQ

What is the function of the SETANT2 pin?

The SETANT2 pin sets the turn-off anticipation time for OUTGATE2 by accepting a DC voltage divider from VCC. At 0–1/3 VCC, t_ANT2 = 75 ns; at 1/3–2/3 VCC, t_ANT2 = 150 ns; at 2/3–VCC, t_ANT2 = 225 ns. This eliminates external timing capacitors and enables field-programmable dead-time adjustment without changing PCB layout.

How does the INHIBIT pin enable discontinuous conduction mode?

The INHIBIT pin disables OUTGATE2 when its voltage exceeds −25 mV (typical), forcing the freewheeling MOSFET OFF before reverse current flows. This prevents output sinking during light-load conditions and extends efficiency down to <1% load - confirmed by measured t_ON(GATE2) = 250 ns at VINHIBIT = +200 mV.

Why does STSR2PCD shut down below 13% duty cycle?

Below 13% duty cycle, the internal logic disables both gate outputs to prevent erratic or incomplete gate drive pulses that could partially turn on MOSFETs and cause shoot-through or excessive conduction loss. This feature is intrinsic to the STSR2P variant and verified across −40°C to +125°C junction temperature range.

Can STSR2PCD operate with transformer-coupled clock inputs?

Yes - the CK pin accepts transformer-coupled clock signals with amplitude ≥2.8 V and slew rate sufficient to cross the 2.6–2.8 V threshold. External clamping diodes (e.g., D3 to VCC) are recommended if peak voltage exceeds VCC + 0.3 V, as specified in Absolute Maximum Ratings for safe operation up to 10 mA injection current.