Key Selection Information
| Selection Parameter | Confirmed Information |
|---|---|
| Topology | Isolated flyback controller |
| Regulation | Optocoupled secondary-side voltage feedback plus primary-side current regulation |
| Startup | Integrated 700-V startup switch stated |
| Switching | Up to 100 kHz; valley-switching operation |
| No-Load Power | Less than 10 mW capability stated |
| Regulation | ±1% voltage / ±5% current stated design capability |
| Protection | Overvoltage, low-line and overcurrent functions; frequency dithering for EMI |
| Exact Package / Packing | SOIC (D), 7 pins; 2500-piece large reel; −40°C to +125°C; marking U28740 |
Product Overview
UCC28740DR is a charger/adapter flyback controller designed around constant-voltage and constant-current output behavior. It uses optocoupled feedback for accurate CV regulation while using primary-side information for current regulation.
Valley switching reduces MOSFET turn-on loss and EMI compared with hard switching at arbitrary drain voltage. Frequency dithering further spreads spectral energy, useful in compact adapters that must pass conducted/radiated limits.
The integrated 700-V startup switch reduces high-value startup resistor loss and helps achieve very low no-load power. The exact DR code is a 2500-piece SOIC-7 reel.
For related devices, see HKEQGOO’s AC-DC Controllers category.
Technical Specifications
| Parameter | Verified Information |
|---|---|
| Manufacturer | Texas Instruments |
| Exact MPN | UCC28740DR |
| Topology | Isolated flyback controller |
| Regulation | Optocoupled secondary-side voltage feedback plus primary-side current regulation |
| Startup | Integrated 700-V startup switch stated |
| Switching | Up to 100 kHz; valley-switching operation |
| No-Load Power | Less than 10 mW capability stated |
| Regulation | ±1% voltage / ±5% current stated design capability |
| Protection | Overvoltage, low-line and overcurrent functions; frequency dithering for EMI |
| Exact Package / Packing | SOIC (D), 7 pins; 2500-piece large reel; −40°C to +125°C; marking U28740 |
| Manufacturer Status | Active / Production |
| Part Marking | U28740 |
Functional Highlights
Hybrid CV/CC feedback targets charger behavior
Optocoupled CV gives tight output-voltage control while primary-side current regulation avoids duplicating full secondary current-control circuitry.
Very-low no-load power is part of the architecture
Startup and burst/frequency-management behavior are designed for adapter efficiency standards, not only full-load conversion efficiency.
Design Considerations
- Design transformer auxiliary winding and optocoupler compensation together with the controller’s sampled regulation scheme.
- Verify valley-switching timing across line/load extremes and MOSFET drain ringing.
- Treat creepage/isolation and secondary feedback safety components as system requirements beyond the IC.
Product Status and Exact Order Code
Texas Instruments/source evidence identifies UCC28740DR as Active / Production; SOIC (D), 7 pins; 2500-piece large tape and reel; −40°C to +125°C; marking U28740.
Related Engineering Resources
Quality & Verification Support
Third-party inspection or testing can be arranged according to customer requirements. Testing fees are borne by the buyer. Additional verification requirements can be discussed before shipment. After an order is placed, physical product, label, packaging, and Date Code photos may be provided where appropriate.
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