The SMSC/Microchip KBC1126-NU Go to product viewer dialog for this item.
What it is: KBC1126NU (aka KBC1126-NU) — a mobile KBC / Super I/O style IC listed under SMSC/Microchip product families; available in QFP/TQFP-128 packages per distributor listings. kbc1126nu datasheet hot
Management: Handles ACPI power states (S0-S5) and battery charging logic. 🌡️ Why is your KBC1126NU running hot? The SMSC/Microchip KBC1126-NU Go to product viewer dialog
Likely content in the datasheet (based on similar KBC devices / search snippets): 🌡️ Why is your KBC1126NU running hot
Second, the datasheet’s electrical characteristics implicitly explain why the KBC1126NU runs “hot” under normal conditions. The device operates at 3.3V but internally steps down voltage for its core. Crucially, its GPIO pins driving external devices (e.g., backlight enable, wireless radio kill switches) have finite source/sink capabilities. When a design flaw—or a physical short—causes a pin to sink excessive current, the chip’s internal resistance generates localized power dissipation ((P = I^2R)). The datasheet’s thermal resistance junction-to-ambient ((\Theta_JA)) value (often 40–60°C/W for the 128-pin QFP package) means that every 0.5W of internal power can raise the die temperature 30°C above ambient. Therefore, a seemingly modest 100mA overcurrent on two or three outputs can push the chip from “warm” to “hot” without triggering an overcurrent protection (OCP) event.
The chip belongs to the SMSC family of mobile controllers and is typically found in professional-grade laptops like the HP EliteBook and ProBook series. Manufacturer SMSC (Microchip) Package Type : TQFP-128 (128-pin Thin Quad Flat Pack). Operating Temperature : Specified for an extended range of negative 40 raised to the composed with power cap C 105 raised to the composed with power cap C Primary Functions Keyboard and touchpad interface management. System power-on/off sequencing (ACPI management). Communication with the BIOS through the LPC bus. Battery charging and monitoring logic. Troubleshooting: Why is the KBC1126NU "Hot"? In the world of laptop motherboard repair
: Specialized hardware for scanning complex key matrices and supporting N-key rollover