| Parameter | Value | | :--- | :--- | | Supply Voltage | 3.3V (±5%) | | I/O Tolerance | 5V tolerant (LPC pins) | | Internal Oscillator | 48 MHz (PLL derived) | | Flash Memory | 128 KB (Embedded) | | RAM | 4 KB | | Package | TQFP-128 (14x14 mm) | | Operating Temp | 0°C to +85°C (Commercial) | | Thermal Resistance (ΘJA) | 45°C/W |
Why the "Hot" Warning? The datasheet reveals that the KBC1126NU can draw up to 250mA during heavy LPC traffic. In standby, it draws 10mA. However, a common failure mode is the chip running scorchingly hot (>85°C) due to:
If your chip is physically hot to the touch without the laptop turning on, suspect a internal die short (requires replacement).
The kbc1126nu datasheet hot search trend reflects a real need in the laptop repair and embedded communities. This chip is the gatekeeper between the user (keyboard) and the silicon (CPU). Understanding its power sequencing (Section 5.2 of the datasheet), thermal limits (Section 7.3), and pinout vulnerabilities (Section 10.1) turns a bricked motherboard into a repairable asset.
Final Pro Tip: Before desoldering a "hot" KBC1126NU, dump the firmware via the LPC debug header (pins 92-95). The 128KB dump contains your laptop's unique serial and board ID. Without it, a new chip will trigger a BIOS lock.
If you found this guide useful, check our repair database for the KBC1126NU register map and the official SMSC datasheet PDF link below.
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The SMSC KBC1126-NU is a 128-pin TQFP/LQFP Keyboard Controller (KBC) and Embedded Controller (EC) commonly found in HP laptops from the Ivy Bridge era (e.g., EliteBook 8570w, ProBook 4530s). Core Specifications Manufacturer: SMSC (acquired by Microchip Technology). Package: 128-pin TQFP / LQFP. Architecture: High-performance embedded 8051-based core. Operating Temp: Extended range of TAcap T sub cap A
Firmware: Does not have internal flash; it reads commands from an external EC ROM or the main BIOS chip. Key Functions & "Hot" Issues This chip acts as the "brain" for hardware management:
Power Sequencing: Manages system power-on/off, sleep modes, and battery charging.
Thermal Monitoring: Controls fan speeds based on CPU/GPU temperatures.
Inputs: Handles the keyboard scan matrix (up to 18x8) and touchpad. Why it might feel "hot" or fail: kbc1126nu datasheet hot
Overheating/Failure: If the chip itself is physically hot to the touch, it typically indicates a short circuit or a failed power rail on the motherboard.
Fan Control Issues: The KBC1126-NU is sometimes "unknown" to standard Linux monitoring tools like lm-sensors. If your laptop is running hot due to fan inactivity, you may need a utility like NoteBook FanControl (NBFC) which specifically supports the KBC1126-NU registers. Pinout Summary KBC1126NU Datasheet, PDF - ALLDATASHEET.COM KBC1126NU Datasheet, PDF - Alldatasheet. ALLDATASHEET.COM KBC1126-NU Schematic Overview | PDF - Scribd
KBC1126-NU Keyboard Controller (KBC) and Super I/O integrated circuit manufactured by (now part of Microchip Technology
. It is commonly found in laptop motherboards, such as those from Dell and HP. Technical Overview
It manages low-level system functions including keyboard input, touchpad interfacing, thermal monitoring (fan control), and power sequencing. Package Type: It typically comes in a 156-pin VFQFN
(Exposed Pad) package designed for surface mounting (SMD/SMT). Related Models: It is part of a family that includes the
, which also features integrated ADC and DAC capabilities with "SentinelAlert" for mobile power management. Datasheet & Support
Finding a full public datasheet for this specific chip can be difficult as SMSC often restricted these documents to OEMs. However, you can find technical summaries and pinout information through the following resources: Datasheet Repositories: Preliminary data and package specs are often hosted on AllDatasheet Jotrin Electronics Inventory & Pricing: For current stock levels or procurement, sites like Win-Source
provide availability status, though supply for this specific part is often limited. Troubleshooting "Hot" Issues If your KBC1126-NU chip is running physically , it usually indicates a hardware failure: Internal Short:
The chip may have failed internally, drawing excessive current. External Short:
A shorted capacitor or component on one of its power rails (often the +3.3V_ALW or +5V_ALW lines) can cause the controller to overheat. Power Surge: | Parameter | Value | | :--- | :--- | | Supply Voltage | 3
Overvoltage from a faulty power adapter or charging circuit can damage the chip's internal logic.
The KBC1126-NU is an industry-standard Keyboard Controller (KBC) and Embedded Controller (EC) integrated circuit (IC) primarily used in laptop motherboards. Developed by SMSC (now a part of Microchip Technology), it serves as a critical bridge between the hardware and the operating system, managing low-level system functions. Technical Specifications and Architecture
The KBC1126-NU is housed in a 128-pin TQFP (Thin Quad Flat Package) or LQFP-128 package, designed for compact surface-mount applications.
Processor Core: Based on the high-performance 8051 microcontroller architecture.
Operating Voltage: Typically operates on a 3.3 V supply (ranging from 3.0V to 3.6V).
Memory: Includes 512 bytes of Data RAM and 2 Kilobytes of scratch ROM/RAM.
Firmware Storage: Unlike some other controllers, it does not feature internal programmable flash memory. Instead, it reads its operating commands from an external EC ROM (SPI Flash) or the main BIOS chip.
Temperature Range: Specified for extended operation from -40°C to 105°C. Core Functionalities
The KBC1126-NU acts as the "nerve center" for a laptop's basic hardware operations:
Input Management: It handles scan functionality for the keyboard matrix (up to 18x8) and touchpad inputs.
Power Sequencing: Manages system power states, including battery charging and motherboard power-on sequences. If your chip is physically hot to the
Thermal Monitoring: Continuously monitors system temperatures and controls fan speeds accordingly to prevent overheating.
Interface Protocols: Utilizes an LPC (Low Pin Count) interface to communicate with the host processor. Troubleshooting "Hot" Components
If a KBC1126-NU chip is physically "hot" to the touch, it typically indicates a hardware failure or a short circuit in the power management system.
Internal Failure: A chip that is too hot to touch while the system is in standby or powered on usually suggests an internal short, requiring a chip replacement.
Peripheral Shorts: Check for shorts in the 3.3V power rail or connected peripherals (like a faulty keyboard or touchpad) that may be drawing excessive current through the controller.
General System Overheating: Ensure that the thermal management system (fans and heatsinks) is clear of dust, as the controller may run hot if it is attempting to manage a system already at its thermal limits.
Detailed technical documentation and stock availability can be verified through distributors like Mouser Electronics (for similar series) or specialized databases like Alldatasheet. How to troubleshoot Overheating, Shutdown or Thermal issues
The KBC1126NU is a 128-pin LQFP Super I/O controller that integrates:
Because this part is legacy/restricted, most top search results are spam or fake. Here are verified sources:
⚠️ Avoid “datasheet download” buttons on random pop-up sites – they often host malware.