The **MHO+28FBD-R** is a high-reliability, radiation-hardened DC-DC converter module typically used in aerospace, defense, and space applications. These units are engineered by manufacturers like **Crane Aerospace & Electronics (Interpoint)**. --- ## 1. Core Specifications and Identification The part number "MHO+28FBD-R" follows a specific nomenclature: | Component | Meaning | Details | | :--- | :--- | :--- | | **MHO+** | Series Name | High-reliability, isolated DC-DC converter series. | | **28** | Input Voltage | Nominal 28V DC (typically handles 16V to 40V). | | **F** | Output Type | Indicates "Fixed" or a specific configuration (Dual/Triple). | | **BD** | Output Voltage | Often represents a specific voltage pair (e.g., ±12V or ±15V). | | **-R** | Radiation Hardened | Indicates "R" grade (Total Ionizing Dose resistance). | --- ## 2. Key Electronic Features These modules are known for their ruggedized internal architecture designed to survive extreme environments. ### A. Power Handling & Efficiency * **Isolation:** Magnetic coupling provides galvanic isolation between input and output, protecting sensitive electronics from power surges. * **Efficiency:** Typically operates at 75% to 85% efficiency depending on the load. * **Output Power:** Usually rated for up to 65W or more (varies by specific sub-model). ### B. Protection Circuitry The internal electronics include several layers of protection: * **Short Circuit Protection:** Indefinite protection against output shorts. * **Undervoltage Lockout (UVLO):** Prevents the device from starting if the input voltage is too low to maintain stable operation. * **Overvoltage Protection:** Clamps the output to prevent damage to downstream components. ### C. Radiation Hardening (The "-R" Suffix) Electronic parts in the MHO+ series are specifically designed to resist: 1. **TID (Total Ionizing Dose):** Usually rated up to 100k Rad(Si). 2. **SEE (Single Event Effects):** Designed to prevent latch-up or burnout caused by heavy ions or protons in space. --- ## 3. Typical Internal Block Diagram The unit is a sophisticated switching power supply (SMPS). Below is a representation of the internal stages: ```mermaid graph LR A[Input Filter] --> B[Power MOSFET Switch] B --> C[Power Transformer] C --> D[Rectifier/Filter] D --> E[Output] F[Feedback Loop] --> B E --> F ``` --- ## 4. Technical Summary Table | Parameter | Typical Value | | :--- | :--- | | **Input Voltage Range** | 16V to 40V DC | | **Operating Temperature** | -55°C to +125°C | | **Isolation Resistance** | 100 MΩ minimum at 500V DC | | **Package Type** | Hermetically sealed metal case | | **Screening Level** | Space Grade (Class H or K equivalent) | ---