New Product Introduction

NXP Semiconductors KM35 MCU Family

KM3x MCU Family enables high accuracy, secure 1-, 2- & 3-phase electricity metering solutions through a powerful analog front end (AFE)

NXP Semiconductors KM35 MCU Family image

KM3x MCU Family enables high accuracy, secure 1-, 2- & 3-phase electricity metering solutions through a powerful analog front end (AFE), by integrating auto-compensated iRTC with HW tamper detection, segment LCD controller, rich security protection and low power features.

The KM3x MCU family includes three subfamilies: KM33, KM34, and KM35; the key differences being the 24-bit sigma-delta model number to address the metering requirement for different regions.

Based on 75MHz Arm® Cortex®-M0+ core, KM35 MCUs offer up to 512 KB flash, 64 KB SRAM, and additional integrated peripherals.


Key features

  • Analog Front End
  • Security & HMI
  • Rich Enablement
  • Enabling single-chip 1,2 & 3-phase meter designs


Additional features

Analog Front End

  • High accuracy AFE with 4 x 24-bit Sigma-Delta ADCs for simultaneous voltage and current measurement.
  • 16-channel, 16-bit SAR ADC inputs for accurate measurement of phase voltage in 3-phase applications

Security & HMI

  • Cortex®-M0+ core, memory protection unit, cross-bar peripheral bridge, GPIO, and DMA enable compliance with WELMEC & OIML standards
  • Active and passive tamper pins with automatic time stamping to protect against external intrusion
  • HW encryptions (MMCAU – DES, 3DES, AES, MD5, SHA-1/SHA-256)CRC (16/32 bits) for data integrity

Rich Enablement

  • Comprehensive peripheral library drivers included in the MCUXpresso ecosystem
  • Filter and FFT based metrology firmware provided free-of-charge
  • TWR-KM35Z75M NXP Tower System Module compatible with multiple peripheral modules from NXP and third parties
  • Certified 1,2 & 3-ph reference designs + metrology firmware
  • Product Longevity Program (15 years)

Enabling single-chip 1,2 & 3-phase meter designs

  • AFE, Security & HMI. Single crystal implementation
  • Single point of calibration during manufacture

Reaching new levels of memory density and integration

  • Up to 512 KB Flash Memory and 64 KB SRAM
  • Memory Mapped Cryptographic Acceleration Unit (MMCAU) for AES encryption



  • Electricity Meters
  • Flow Meters (e.g., Heat, Water, Gas)
  • Industrial Measurement and Sensing


Available tools

TWR-KM35Z75M Tower System Module

The TWR-KM35Z75M board is designed to work either in standalone mode or as part of the NXP Tower System, a modular development board platform that enables rapid prototyping and tool re-use through reconfigurable hardware. Begin constructing your Tower System evaluation board platform today by visiting for additional Tower System boards and compatible peripherals.

  • Tower-compatible microcontroller module
  • KM35Z512VLQ7 MCU (75 MHz, 512 KB Flash, 64 KB RAM, low power, LQFP144 package)
  • USB interface with micro-B USB connector
  • Large 160-segment glass LCD
  • On-board debug circuit: Open source SWD (OpenSDA) with virtual serial port
  • Three-axis accelerometer/anti-tamper tilt sensor (MMA8451Q)
  • Three user-controllable LEDs
  • Two user push-button switches for GPIO interrupts
  • One user push-button switch for tamper detection
  • One user push-button switch for MCU reset
  • Potentiometer
  • Headers for direct GPIO and ADC access
  • External tamper pins
  • Independent, battery-operated power supply for real-time clock (RTC) and tamper detection modules
  • IRDA support
  • NTC temperature sensor
  • General-purpose tower plug-in (TWRPI) socket

Software Enablement

The TWR-KM35Z75M is enabled using NXP MCUXpresso SDK, MCUXpresso Config Tools, MCUXpresso IDE and a large partner ecosystem.

Integrated development environments

  • IAR Embedded Workbench®
  • Arm Keil® Microcontroller Development Kit
  • NXP MCUXpresso
    • An open-source software development kit (SDK)
    • An easy-to-use integrated development environment (IDE)
    • A comprehensive suite of system configuration tools, including pins, clocks, SDK builder and more
    • Broad Arm ecosystem support through NXP Connect partners