The F4901 1.1A 24V schematic can be used in various applications, including:
At 24V and 1.1A continuous load, use a minimum trace width of 30 mils (0.76 mm) for 1 oz/ft² copper thickness to keep trace temperature rise below 10°C.
The board relies on a stable main power rail. Because microcontrollers and logic ICs cannot operate at 24V, the schematic features a multi-stage buck regulation network.
Below is a conceptual layout of how this specific sub-circuit is structured: f4901 1.1a 24v schematic
📌 You can find the exact placement of this component by searching for the Wistron "Queen" or "Hummingbird" motherboard schematics, specifically looking at the USB or LCD Connector pages.
R=24V−2.1V0.01A=21.9V0.01A=2190Ω (Standard 2.2kΩ resistor)cap R equals the fraction with numerator 24 V minus 2.1 V and denominator 0.01 A end-fraction equals the fraction with numerator 21.9 V and denominator 0.01 A end-fraction equals 2190 space cap omega (Standard 2.2k cap omega resistor) 4. Thermal Derating: The Critical Design Trap
Manufacturers rarely publish the "F4901" schematic openly because it is a generic OEM design. However, you can find equivalent schematics by searching for: The F4901 1
Polymeric Positive Temperature Coefficient (PPTC) Resettable Fuse / Overcurrent Protection Device. Standard F4901 24V Protection Circuit Schematic
R=Vin−VfIfcap R equals the fraction with numerator cap V sub i n end-sub minus cap V sub f and denominator cap I sub f end-fraction , the forward voltage of a standard green LED ( Vfcap V sub f ) is roughly , and the target current ( Ifcap I sub f
A tripped PPTC will be physically hot to the touch. Below is a conceptual layout of how this
: This is typically a proprietary manufacturer part number, a specific circuit board revision identifier, or a designator for a specialized integrated circuit (IC) or fuse link. In many industrial applications, "F" designators also point directly to a primary protection line.
It acts as a safety barrier for the LCDVDD or Backlight Power rails, protecting delicate display components from over-current conditions.
: If the F4901 is a surface-mount power IC or regulator, place thermal vias directly beneath its exposed pad to pull heat away into the inner board layers. 5. Troubleshooting the F4901 1.1A 24V Circuit
Does the schematic protect your device?