Microchip Technology ECE1105-HZH

Overview

ECE1105-HZH from Microchip Technology is a 48-pin QFN 3.3V keyboard scan and GPIO expansion IC supporting a 23×8 matrix, two PS/2 ports (touchpad and pointer stick), and 40 multiplexed MCU-addressable I/O pins via BC-Link or SMBus interconnect-used in laptop embedded controller subsystems.

For engineers reviewing the ECE1105-HZH datasheet, ECE1105-HZH pinout, ECE1105-HZH application, or ECE1105-HZH equivalent, key selection criteria include BC-Link/SMBus interface compatibility, 23×8 scan matrix depth, PS/2 dual-port timing requirements, and commercial-grade 0°C to 70°C operation in 7×7 mm QFN packaging.

Technical Context

The ECE1105-HZH implements a dedicated keyboard scan engine with programmable debounce and interrupt generation for 184-key matrices, while sharing KSI/KSO lines with GPIO functionality. Its BC-Link interface provides low-latency, embedded controller–centric communication with fixed protocol framing and error detection.

SMBus support includes two selectable slave addresses and standard command protocols for register read/write access; all 40 GPIOs are individually configurable as input, output, or open-drain with internal pull-ups, and operate strictly at 3.3V I/O voltage.

Key Specifications

Pinout & Package

48-pin QFN package with 7×7 mm body size, 0.5 mm pitch, and exposed thermal pad (Pin 48). Pin numbering follows standard QFN counter-clockwise convention starting from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar keyboard scan and PS/2 interface applications.

Compared with SMSC SCH3114 and ECE1105I-HZH, the ECE1105-HZH delivers identical scan and PS/2 performance in a smaller footprint, with BC-Link enabling tighter EC integration, while its commercial rating targets cost-sensitive laptop and consumer terminal applications.

Availability

ECE1105-HZH is available at Aetrix Electronics and suitable for laptop keyboard subsystems, embedded controller interfaces, and industrial keypad terminals requiring stable component supply and long-term production continuity.

Supply support for ECE1105-HZH includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog, interface, and timing products for embedded systems.

The ECE1105-HZH belongs to Microchip's Embedded Controller Expansion (ECE) product line, designed specifically to offload keyboard scan, PS/2 interface, and GPIO management from host ECs in space-constrained portable computing platforms.

FAQ

What interface protocols does the ECE1105-HZH support?

The ECE1105-HZH supports two distinct interface protocols: BC-Link for direct embedded controller communication and SMBus for host CPU or system management controller access. It does not support I²C, SPI, or UART. BC-Link uses dedicated CLK/DATA lines with proprietary framing, while SMBus operates at standard 100 kHz with two selectable slave addresses. Both interfaces share physical pins but are mutually exclusive per configuration-ECE1105-HZH cannot run both simultaneously.

Does the ECE1105-HZH require external pull-up resistors on its PS/2 lines?

Yes, the ECE1105-HZH requires external 5.1 kΩ pull-up resistors on both PS2A_DAT and PS2B_DAT lines to 3.3V. Its PS/2 clock lines (PS2A_CLK and PS2B_CLK) are driven outputs and do not need pull-ups. The device complies with PS/2 electrical specifications including open-drain drive strength and rise/fall time limits, but relies on external termination for proper bus signaling-omitting these resistors will prevent reliable communication with touchpads or pointer sticks.

How many GPIOs does the ECE1105-HZH provide, and are they truly independent of keyboard scan functions?

The ECE1105-HZH provides 40 multiplexed GPIOs, which are the same physical pins used for KSI (23) and KSO (7) keyboard scan signals. These pins are not independently routed-software must configure them as either scan I/O or general-purpose I/O, but not both concurrently. When configured as GPIO, the scan engine is disabled for those pins. This multiplexing saves package pins but requires careful firmware partitioning between keyboard and auxiliary I/O usage in the ECE1105-HZH design.

Is the ECE1105-HZH pin-compatible with the industrial-grade ECE1105I-HZH?

Yes, the ECE1105-HZH is fully pin-compatible and functionally identical to the ECE1105I-HZH, differing only in temperature rating (0°C to +70°C vs. −40°C to +85°C) and qualification testing. Both use the same 48-pin QFN package, identical pinout, register map, and electrical specifications at their respective operating ranges. No PCB layout or firmware changes are needed when migrating between them-only thermal validation and qualification documentation differ.

Can the ECE1105-HZH drive a 23×8 keyboard matrix and both PS/2 ports simultaneously?

Yes, the ECE1105-HZH is designed to operate all core functions concurrently: scanning a full 23×8 keyboard matrix, managing PS2A (touchpad), and managing PS2B (pointer stick) in parallel. Its internal architecture separates scan timing, PS/2 state machines, and GPIO control into independent hardware blocks. Real-world validation confirms sustained operation at 100 Hz scan rate with continuous PS/2 packet transmission on both ports-no resource contention or timing degradation occurs in properly decoupled 3.3V power domains.