KM SERIES MCUs FOR
PRECISION METROLOGY
Enabling high accuracy, secure 1-, 2- and
3-phase electricity metering solutions, as
well as flow meter and other precision
measurement applications, through powerful
analog front end (AFE), rich security
protection and HMI functionality.
FACT SHEET
KM SERIES MCUs
TARGET APPLICATIONS
• Electricity meters
• Flow meters (e.g., heat, water, gas)
• Industrial measurement and sensing
• EV charger
OVERVIEW
KM series MCUs are based on the 32-bit Arm® Cortex®-M0+
core and provide a powerful analog front end that
is configurable for different regions, enabling power
calculations with 0.1 percent accuracy. A high accuracy
auto-compensated iRTC with hardware tamper detection
delivers less than 5 PPM drift over temperature. In
addition of security, communication interfaces and multiple
low-power features, KM3x supports segment LCD for
applications requiring HMI functionality. Metrology firmware
for calculating active, reactive and apparent power using a
variety of algorithms is provided free of charge. Pre-certified
reference designs for Europe, China, India, the U.S. and
Japan are available for customer evaluation.
SPECIFICATIONS
• High-performance Cortex-M0+ core, up to 75 MHz
of core clock frequency
• Up to 512 KB program flash, up to 64 KB SRAM
• Supports v6-M instruction set architecture including all
16-bit v7-M instructions plus a number of 32-bit
Thumb®-2 instructions
• Phase-locked loop to generate clocks for analog front end
– Input range: 31.25–39.0625 kHz
– Output range: 11.72–14.65 MHz
• Frequency-locked loop to generate core, system and
flash clocks
– Input range: 31.25–39.0625 kHz
– Output range: 20–75 MHz
• Flexible low-power modes to provide power optimization
based on application requirements
• 32 kHz and 4 MHz internal reference clock
• Operating Characteristics
– Voltage range: 1.71–3.6 V (without AFE)
– Voltage range: 2.7–3.6 V (with AFE)
– Temperature range: –40 °C to +105 °C
KM MCU SERIES BLOCK DIAGRAM
Core
®
Cortex® -M0+
ARM
Up to 75 MHz
SWD
Interface
Interrupt
Controller
Security Display
16/32 Cyclic
Redundancy
Check
MMCAU
Random
Number
Generator
Tamper
Detection
H/W Arithmetic
Segment LCD
Optional
MTB
Unit
Controller
(Up to 448
Segments,
56 x 8)
System Memory
Watchdog
BME
Low-Leakage
Wake-Up Unit
Inter Peripheral
Crossbar
EWM
MPU
Timers Communication Interfaces Clocks
4 x Quad Timer
Up to 2 x
Low-Power Timer
2 x Periodic
Interrupt Timers
IRTC on vBatt
with T° comp.
Programmable
Delay Block
64-512 KB Flash
16-64 KB SRAM
Up to 3 x 16-bit SPI
Up to 5 x
UARTs
(2 x ISO7816,
1 x LPUART)
Up to 99 GPIO
Measurement Front End
Up to 3 x
HSCMP
16-ch., 16-bit
SAR ADC
1.2 V VREF
2
2 x I
C
4 x 24-bit Sigma
Delta ADC
Up to
4 x PGA
Phase Shifter
Phase Locked
Loop
Frequency
Locked Loop
Low/High
Frequency
Oscillators
Internal
Reference
Clocks
KM SERIES SELECTOR GUIDE
SubFamily
KM14
KM33
KM34
KM35
Part Number
Flash (KB)
CPU Frequency (MHz)
MKM14Z128(A)xxx5 50 128 16 2 (2/-) 1 2 4 20 Y TWR-KM34Z50M(V3)
MKM14Z64(A)xxx5 50 64 16 2 (2/-) 1 2 4 20 Y TWR-KM34Z50M(V3)
MKM33Z128(A)xxx5 50 128 16 4 (2/-) 2 2 3 38–68 Y Y TWR-KM34Z50M(V3)
MKM33Z64(A)xxx5 50 64 16 4 (2/-) 2 2 3 38–68 Y Y TWR-KM34Z50M(V3)
MKM34Z128(A)xxx5 50 128 16 4 (2/-) 2 2 4 68 Y TWR-KM34Z50M(V3)
MKM34Z256xxx7 75 256 32 5 (2/1) 2 2 4 72–99 Y Y TWR-KM34Z75M
MKM35Z256xxx7 75 256 64 5 (2/1) 2 3 4 72–99 Y Y TWR-KM35Z75M
MKM35Z512xxx7 75 512 64 5 (2/1) 2 3 4 72–99 Y Y TWR-KM35Z75M
KEY FEATURES
Analog Front End
• 24-bit sigma-delta ADC with 94 dB SNR
• Programmable gain amplifier
with gains from 1 to 32 with low
temperature drift
• High precision internal voltage
reference with low temperature drift
C
2
I
UART
SPI
SRAM (KB)
(ISO 7816/LPUART)
ADC (24-bit (∑Δ))
Security
• Memory mapped cryptographic
acceleration unit (MMCAU) for
AES encryption
• Memory protection unit, AIPS
(peripheral protection), random
number generator, CRC
Package
HH LH LL LQ
Total I/Os
44 LGA
64 LQFP
(5 x 5, 0.65 mm)
(10 x 10, 0.5 mm)
Interface
• LCD segment driver up to 448
• High accuracy RTC +-5 PPM over
• Up to five UART, three SPI, two I2C
100 LQFP
144 LQFP
(14 x 14, 0.5 mm)
(20 x 20, 0.5 mm)
(56 x 8) segments
temperature range
Development
Hardware
• Up to 16-channel, 16-bit SAR ADC