Key Selection Information
| Selection Parameter | Confirmed Information |
|---|---|
| Control | Peak current-mode PWM |
| Frequency | Up to 1 MHz |
| Startup Current | 50 µA typical / 100 µA maximum stated |
| Operating Current | 2.3 mA stated at 52 kHz family condition |
| Gate Drive | ±1 A peak |
| Current Limit | 35 ns stated cycle-by-cycle response |
| UVLO / Duty | 8.4 V / 7.6 V UVLO class; 50% maximum duty-cycle variant |
| Exact Package / Packing | SOIC (D), 8 pins; 2500-piece large reel; −40°C to +125°C; marking 28C45 |
Product Overview
UCC28C45DR shares the UCC28C4x low-power current-mode architecture but intentionally limits maximum duty cycle to 50%. This is useful in transformer/forward-derived applications where enforced off-time helps guarantee magnetic reset.
The device retains low startup current, fast current limiting and a ±1-A gate driver, making it a drop-in-style modernization for many UC3845-class designs.
Because C43 and C45 look nearly identical in headline frequency/UVLO data, duty-cycle limit must be treated as a first-order topology constraint rather than an incidental suffix.
For related devices, see HKEQGOO’s AC-DC Controllers category.
Technical Specifications
| Parameter | Verified Information |
|---|---|
| Manufacturer | Texas Instruments |
| Exact MPN | UCC28C45DR |
| Control | Peak current-mode PWM |
| Frequency | Up to 1 MHz |
| Startup Current | 50 µA typical / 100 µA maximum stated |
| Operating Current | 2.3 mA stated at 52 kHz family condition |
| Gate Drive | ±1 A peak |
| Current Limit | 35 ns stated cycle-by-cycle response |
| UVLO / Duty | 8.4 V / 7.6 V UVLO class; 50% maximum duty-cycle variant |
| Exact Package / Packing | SOIC (D), 8 pins; 2500-piece large reel; −40°C to +125°C; marking 28C45 |
| Manufacturer Status | Active / Production |
| Part Marking | 28C45 |
Functional Highlights
50% limit can protect magnetic reset margin
The controller prevents duty commands beyond half a cycle, simplifying transformer reset assumptions in applicable topologies.
BiCMOS implementation lowers controller power
Low startup and operating current can improve standby efficiency versus older bipolar PWM controllers.
Design Considerations
- Confirm the topology can deliver required output at a 50% duty ceiling across low line.
- Use current-transformer/shunt filtering that preserves the 35-ns-class protection intent.
- Do not substitute C43/C45 solely on pin compatibility.
Product Status and Exact Order Code
Texas Instruments/source evidence identifies UCC28C45DR as Active / Production; SOIC (D), 8 pins; 2500-piece large tape and reel; −40°C to +125°C; marking 28C45.
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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