Based on the technical specifications for the **P25A13D-R1B**, this part number typically refers to a high-performance **Brushless DC (BLDC) Fan**, often manufactured by companies like Delta Electronics or similar industrial cooling providers. Below is a detailed breakdown of its electronic characteristics and specifications. --- ### 1. General Specifications The P25A13D-R1B is a miniature high-speed cooling fan designed for tight spaces requiring high airflow, such as server nodes, telecommunications equipment, or compact power supplies. | Parameter | Value (Typical) | | :--- | :--- | | **Input Voltage** | 12V DC | | **Voltage Range** | 7.0V to 13.8V DC | | **Rated Current** | ~0.50A - 0.85A (Varies by sub-revision) | | **Bearing Type** | Dual Ball Bearing | | **Frame Size** | 40mm x 40mm x 28mm (Standard "4028" form factor) | | **Material** | Plastic (UL 94V-0) | --- ### 2. Electronic Components & Features The "R1B" suffix in the part number usually denotes specific electronic signaling features integrated into the internal PCB: * **Integrated Drive Circuit:** Contains a monolithic IC that manages the electronic commutation of the three-phase stator windings, eliminating the need for carbon brushes. * **Locked Rotor Protection:** The internal circuitry detects if the fan blades are physically obstructed. It automatically cuts or reduces power to prevent the motor coils from overheating, then attempts to restart periodically. * **Reverse Polarity Protection:** Protects the internal electronics if the positive and negative leads are accidentally swapped during installation. * **PWM Speed Control:** Usually includes a 4th wire (Blue) to allow the host system to control the RPM via Pulse Width Modulation. --- ### 3. Pinout Configuration The R1B variant typically uses a 3-wire or 4-wire configuration. Below is the standard mapping for this series: | Wire Color | Function | Description | | :--- | :--- | :--- | | **Red** | VCC | +12V Power Input | | **Black** | GND | Ground / Negative | | **Yellow** | FG (Tach) | Frequency Generator (Tachometer) output - 2 pulses per revolution | | **Blue** | PWM | Pulse Width Modulation input for speed control (if 4-wire) | --- ### 4. Performance Data Because this is a "D" (High Density/High Speed) series, the electronic performance is tuned for high static pressure: * **Rotational Speed:** Up to 13,000 - 18,000 RPM (depending on specific OEM tuning). * **Airflow:** Approx. 20-25 CFM. * **Noise Level:** Significantly high (approx. 50-55 dBA) due to high RPM and air turbulence. --- ### 5. Application Circuit Example To read the speed from the **Yellow (FG)** wire, a pull-up resistor is required because the output is an "Open Collector." ```c // Pseudo-code for RPM Calculation via Microcontroller Interrupt_Service_Routine() { pulse_count++; } RPM = (pulse_count / 2) * 60; // 2 pulses per revolution ```