STMicroelectronics STSR30D-TR

Overview

STSR30D-TR from STMicroelectronics is a synchronous rectifier smart driver IC designed for secondary-side gate control in low-voltage, high-efficiency flyback converters. It delivers 1.5A peak source/sink gate drive, operates from 4V to 5.5V supply, supports 20–500 kHz switching, features 700 ns inhibit blanking time, and implements cycle-by-cycle anticipation logic to prevent shoot-through during primary switch transitions - used in USB PD adapters and compact AC/DC power supplies.

For engineers reviewing the STSR30D-TR datasheet, STSR30D-TR pinout, STSR30D-TR application in flyback synchronous rectification, or STSR30D-TR equivalent for secondary-side MOSFET driving, this page provides verified functional specifications, validated SO-8 pin mapping, confirmed timing behavior (tANT = 150–300 ns), real-world discontinuous-mode inhibition behavior, and direct alternative part comparisons with documented electrical and application-level differences.

Technical Context

The STSR30D-TR uses a 15 MHz internal oscillator synchronized to the CK input to generate precise turn-off anticipation for OUTGATE, with three user-selectable tANT values (150/225/300 ns) set via voltage division on SETANT. Its dual-ground architecture isolates SGLGND (logic reference) from PWRGND (high-current return) to suppress noise coupling into timing control.

INHIBIT detects reverse current via synchronous FET drain voltage, triggering forced gate turn-off during discontinuous conduction mode; the 700 ns blanking window rejects ringing-induced false triggers. DISABLE enables full device shutdown (<50 µA ICC), while UVLO (3.3–3.6 V turn-off) ensures clean start-up and brown-out protection.

Key Specifications

Pinout & Package

STSR30D-TR is housed in an SO-8 package (5.0 × 4.0 mm body, 1.27 mm pitch), rated for TJ = –40°C to +125°C, with R_thj-amb = 160°C/W on single-layer PCB and R_thj-case = 40°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6908GJ-Z and UCC24612-2QDRQ1, STSR30D-TR uniquely offers user-programmable anticipation, dual-ground noise immunity, and 700 ns hardware blanking - making it optimal for cost-sensitive, high-density consumer flyback adapters where layout-induced timing variation must be actively compensated.

Availability

STSR30D-TR is available at Aetrix Electronics and suitable for USB PD adapters, laptop AC/DC chargers, industrial 24 V flyback supplies, and medical-grade AC/DC modules requiring stable component supply, consistent SO-8 sourcing, and long-term lifecycle support.

Supply support for STSR30D-TR 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 microcontrollers, power ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The STSR30 product line targets high-efficiency secondary-side synchronous rectification in isolated flyback converters, emphasizing noise-immune timing control, programmable dead-time adaptation, and ultra-low standby power - specifically engineered for compact, thermally constrained AC/DC adapters.

FAQ

What is the purpose of the SGLGND and PWRGND separation in STSR30D-TR?

SGLGND serves as the dedicated reference for all internal comparators, oscillators, and logic circuits, while PWRGND carries high di/dt gate drive return current. This physical and electrical separation prevents magnetic and conductive coupling of switching noise into timing-critical nodes - a key requirement for stable CK synchronization and accurate INHIBIT threshold detection in noisy flyback environments.

How does the INHIBIT pin detect discontinuous conduction mode?

The INHIBIT pin monitors voltage across the synchronous rectifier MOSFET's drain-source path. When current reverses (indicating DCM onset), the pin senses a negative voltage exceeding the –25 mV threshold (VH), triggering immediate OUTGATE turn-off. The 700 ns blanking window ignores transient ringing during primary switch turn-off, ensuring only true reverse current initiates action.

Can STSR30D-TR operate with a 3.3 V supply?

No. STSR30D-TR requires a minimum VCC of 3.7 V to initiate operation and sustains function only down to 3.3 V before UVLO disables output. Its specified supply range is 4.0–5.5 V; operation below 4.0 V violates datasheet limits and risks unreliable CK detection, weak gate drive, and undefined INHIBIT threshold behavior.

What external components are mandatory for basic STSR30D-TR operation?

Mandatory components include: two 100 nF ceramic capacitors (C1, C2) placed adjacent to VCC and SGLGND per Figure 2; a pull-up resistor (R3) on CK; and voltage-divider resistors (R1, R2) on SETANT to select tANT. Optional but recommended: clamping diodes (D1, D2) on INHIBIT to protect against overvoltage and negative excursions beyond absolute maximum ratings.