The SD1728 is a 50V epitaxial silicon NPN planar transistor designed primarily for SSB and VHF communications. This device utilizes emitter bal- lasting for improved ruggedness and reliability.
This datasheet describes the SGS-THOMSON SD1728 (TH430) RF and microwave NPN planar transistor, optimized for SSB and VHF communications. It includes absolute maximum ratings, electrical specifications, and thermal characteristics such as a 0.4 °C/W junction‑case resistance.
Typical performance graphs show output power up to 250 W PEP at 30 MHz with 14.5 dB gain, as well as bias and mounting circuit diagrams and detailed mechanical package dimensions.
| Collector‑Base Voltage | 110 V |
|---|---|
| Collector‑Emitter Voltage | 55 V |
| Emitter‑Base Voltage | 4.0 V |
| Device Current | 40 A |
| Power Dissipation | 330 W |
| Junction Temperature | +200 °C |
| Storage Temperature | -65 °C to +150 °C |
| Thermal Resistance (J‑C) | 0.4 °C/W |
The transistor can withstand up to 55 V between collector and emitter.