The **M3H28TDG-R** is a high-reliability, radiation-hardened (Rad-Hard) isolated DC-DC converter typically manufactured by **Moog (formerly Crane Aerospace & Electronics/Interpoint)**. These components are specifically designed for space applications, such as satellites and exploratory probes. --- ### 1. Key Technical Specifications The "M3H" series represents a triple-output architecture designed to operate in extreme environments. | Feature | Specification | | :--- | :--- | | **Input Voltage** | 18V to 50V DC (28V Nominal) | | **Output Configuration** | Triple Output (typically +5V and ±12V or ±15V) | | **Power Rating** | Approximately 25W to 40W (model dependent) | | **Efficiency** | ~75% to 83% | | **Isolation** | 100 MΩ minimum at 500V DC | | **Operating Temp** | -55°C to +125°C | --- ### 2. Electronic Architecture & Components The internal construction of the M3H28TDG-R utilizes specialized materials to ensure survival in the vacuum of space. * **Thick-film Hybrid Technology:** Instead of a standard PCB, it uses a ceramic substrate with printed resistors and mounted bare-die components to minimize weight and improve thermal conductivity. * **Magnetic Feedback:** Uses a transformer-based feedback loop rather than optoisolators, as optoisolators degrade rapidly under ionizing radiation. * **Input Filter:** Includes an internal EMI filter to minimize conducted emissions, complying with MIL-STD-461 standards. * **Hermetic Packaging:** The unit is enclosed in a seam-welded metal case to prevent outgassing and protect against atmospheric contaminants during launch. --- ### 3. Radiation Hardness (Rad-Hard) Features The "R" suffix in the part number usually denotes the radiation hardness level. 1. **TID (Total Ionizing Dose):** Typically rated for **100 krad(Si)**. This ensures the semiconductor junctions do not fail over long-term exposure to space radiation. 2. **SEE (Single Event Effects):** Designed to be immune to "Single Event Latch-up" (SEL) up to high LET (Linear Energy Transfer) levels (often $>80 \text{ MeV}\cdot\text{cm}^2/\text{mg}$). 3. **ELDRS:** Tested for Enhanced Low Dose Rate Sensitivity to ensure reliability during the slow accumulation of radiation in deep space. --- ### 4. Application Use Cases Due to its high cost and specialized certification, this part is used exclusively in high-stakes environments: * **Low Earth Orbit (LEO) & Geostationary (GEO) Satellites:** Powering command and data handling (C&DH) systems. * **Launch Vehicles:** Powering guidance computers. * **Deep Space Missions:** Providing stable power to scientific instrumentation.