The **V28A5T175BL** is a high-density, isolated DC-DC converter module belonging to the **Maxi** series manufactured by **Vicor Corporation**. These modules are known for their high reliability, efficiency, and use of ZCS/ZVS (Zero-Current Switching / Zero-Voltage Switching) technology. --- ## 1. Core Technical Specifications The model number provides specific details about the part's performance characteristics. | Parameter | Specification | Details | | :--- | :--- | :--- | | **Input Voltage (Nominal)** | 28 VDC | Range: 18V to 36V | | **Output Voltage** | 5 VDC | Adjustable (Trim) via external resistor | | **Output Power** | 175 Watts | High power density for its size | | **Efficiency** | ~83% - 85% | Typical for the 28V input range | | **Package Type** | Maxi | Full-size module (approx. 4.6" x 2.2") | | **Mounting Style** | Through-hole | Specialized pin configuration (Short/Long pins) | --- ## 2. Key Electronic Features ### A. Zero-Current Switching (ZCS) Unlike traditional PWM converters, Vicor modules use ZCS. This allows the internal MOSFETs to switch only when the current is at zero, which significantly reduces switching losses and electromagnetic interference (EMI). ### B. Control Interface The module features several logic-level pins for system integration: * **PR (Parallel):** Allows multiple units to be connected in parallel for higher power or N+1 redundancy. * **PC (Primary Control):** Used for remote enable/disable and to monitor the status of the module. * **SC (Secondary Control):** Used as a trim pin to adjust the output voltage above or below the nominal 5V. ### C. Protection Circuitry The module is "ruggedized" and includes several internal safety layers: * **Overvoltage Protection (OVP):** Shuts down if the output exceeds a safe limit. * **Short Circuit Protection:** Continuous current limiting. * **Thermal Shutdown:** Protects the module if internal temperatures exceed roughly 105°C to 115°C. --- ## 3. Application Use Cases Because of the **28V input** rating, this part is specifically designed for: 1. **Military & Aerospace:** 28V is the standard power bus for vehicles and aircraft. 2. **Industrial Controls:** Used in 24V/28V DC systems where high isolation (3000Vrms) is required. 3. **Heavy Equipment:** Powering onboard computers or sensors from battery-backed systems. --- ## 4. Pin Configuration Diagram (Simplified) ```text +---------------------------------------+ | (1) +IN +OUT (9)| | (2) PC +S (8)| | (3) PR SC (7)| | (4) -IN -S (6)| | -OUT (5)| +---------------------------------------+ ``` *(Note: +S and -S are Sense pins used to compensate for voltage drops in wiring.)*