Q1: Is STR F6267 obsolete? A: While not in active high-volume production, it is classified as "NRND" (Not Recommended for New Designs) by Sanken. However, updated datasheets are maintained for repair and legacy manufacturing. The “updated” status refers to revisions clarifying thermal data and OCP thresholds.
Q2: Can I replace STR F6267 with STR F6268? A: No. The F6268 has a higher Rds(on) and lower current rating (6A vs 8A). Using it in a 150W design designed for the F6267 will cause overheating and premature failure. Always verify the suffix.
Q3: Does the updated PDF include PCB layout guidelines? A: Yes. The latest revision adds a dedicated section on Kelvin connection for the Source pin to prevent false OCP triggering due to common impedance coupling.
Q4: What is the expected switching frequency? A: The frequency varies with load and line voltage, ranging from 20kHz (heavy load) to 120kHz (light load). At no load, it drops to burst mode (~500Hz bursts).
Before you wire this into your PCB, confirm these five pins against the updated datasheet:
Updated Note: Many "STR-F6267" failures are actually due to a faulty startup resistor (Rstart) or a dried-out VCC capacitor on Pin 3. The latest datasheet adds a note to use Low ESR capacitors here. str f6267 datasheet pdf updated
The STR-F6267 comes in a 5-pin TO-220F (Full Mold) package. This isolated package simplifies heatsinking (no mica insulator required). Here is the detailed pin assignment:
| Pin No. | Symbol | Description | Voltage/Function | | :--- | :--- | :--- | :--- | | 1 | D (Drain) | MOSFET drain & internal start-up current input | High voltage (650V max) | | 2 | S (Source) | MOSFET source & primary ground reference | 0V (GND) | | 3 | VCC | Control IC supply voltage | 16V typ. (OVP at 24V) | | 4 | FB (Feedback) | Feedback pin from secondary side (opto-coupler) | 0 to 6V range | | 5 | OCP/FB (Combined) | Overcurrent/FB latch input (often labeled as "GND" in older datasheets) | < 0.75V for operation |
Important Update: Newer datasheet revisions (post-2022) clarify that Pin 5 is a multifunction ground/current sense pin. Do not confuse this with the main Source (Pin 2). Both must be connected to primary ground with short traces.
When you locate the updated PDF, focus on these three sections:
| Pin | Name | Function | |-----|--------|------------------------------------------| | 1 | FB/OLP | Feedback input & overload protection | | 2 | S/OCP | Source pin for current sense & OCP | | 3 | VCC | Supply voltage (startup & operation) | | 4 | GND | Ground | | 5 | DRAIN | Internal MOSFET drain & HV startup | Q1: Is STR F6267 obsolete
Note: Some variants have additional NC pins. Verify with the updated datasheet.
Pay attention to Figure 6: "Quasi-Resonant Operation." The updated datasheet adds notes on valley switching, which reduces turn-on loss. The IC detects voltage dips on the Drain after demagnetization.
The original datasheets for the STR-F6267 have been circulating online for over a decade. Many of those scanned copies are blurry, missing the "Typical Application Circuit" page, or contain obsolete part numbers for external components (diodes, transformers).
The newly updated PDF (Rev. 3.1) addresses the following critical areas:
1. Accurate Overcurrent Protection (OCP) Graphs Previous versions had a vague curve regarding the "Detect Voltage" (Pin 3). The updated document provides precise threshold voltages (Vth) for the OCP pin across varying temperatures. This helps you stop nuisance tripping when the load is technically within spec. Updated Note: Many "STR-F6267" failures are actually due
2. Revised Start-Up Circuit Details Many repair technicians have been using the wrong value for the Vcc capacitor. The new datasheet clarifies the required Start-up current supply (max 100µA) and the recommended Vcc capacitance (47µF–100µF) to prevent "hiccup mode" during power-on.
3. Corrected Pinout Clarifications While the pinout hasn't physically changed (Pin 1: OCP/FB, Pin 2: Source, Pin 3: FB/OCP, Pin 4: Vcc, Pin 5: Drain), the new document adds high-resolution 3D renderings of the Full Mold Isolated Package. This eliminates confusion regarding heatsink mounting and isolation requirements.
The STR-F6267 is a current‑mode PWM controller with an integrated high‑voltage MOSFET, designed for flyback converter topologies in low‑to‑medium power applications. It belongs to the STR‑F6200 series, typically used in AC‑DC adapters, standby power supplies, and auxiliary power for consumer electronics (TVs, monitors, white goods).
Key features (typical of the series):