TMR-based closed-loop sensor for high-current coreless applications

  • First Micronas’ brand TMR-based current sensor
  • Non-intrusive, galvanically isolated contactless current measurement
    based on closed-loop TMR technology
  • Smallest module integration since no magnetic-field core concentrator
    is required
  • ISO26262 ASIL-B ready and AEC-Q100 qualified

SAN JOSE, Calif.–(BUSINESS WIRE)–TDK Corporation (TSE: 6762) is expanding its Micronas magnetic sensor
portfolio with the CUR 423x sensors developed for current measurements
in automotive and industrial applications. The new sensors, marketed
under the trademark curSENS, are the first Micronas branded products
based on the TDK TMR technology. This technology has already been proven
in existing TDK automotive sensor products and is now paving the way for
innovative coreless current-sensing applications. The new sensors
highlight the synergies created in TDK’s magnetic sensor business,
following the acquisition of Micronas in 2016.

The CUR 423x sensors are the first family members, suited for DC and AC
measurements in high-power applications and is able to measure currents
above 1200 A. The galvanically isolated power and sensing circuits are
of particular benefit in high-voltage battery monitoring systems of
hybrid and electric vehicles (xEV). A very good signal-to-noise ratio
and a total error below 1% (full scale) over temperature allow for
precise current measurements in applications with a signal bandwidth of
up to 5 kHz. Samples will be available from the fourth quarter of 2019.

All the necessary components for a closed-loop circuit, such as
compensation coil, Rshunt, and TMR sensor bridge, are integrated into a
small 1 mm thin industry standard TSSOP16 SMD package. By avoiding the
need for a large magnetic-field concentrator core, space and costs can
be saved. Digital offset and gain temperature compensation, low-pass
filter, and clamping can easily be programmed by using TDK-Micronas’
programming toolchain.

Two variants are available that offer magnetic-flux density ranges of
either ±7 mT or ±40 mT. A fine adjustment of the field ranges allows for
adaptation to different application current ranges. Current sensing
modules equipped with CUR 423x can be programmed via the output pin
during the manufacturing process. Customer-selectable output interfaces,
like SENT acc. to SAEJ2716 Rev.4, SPI or full ratiometric analog, allow
for flexible adaptation to application requirements.

The CUR 423x is developed according to ISO26262. ASIL-B ready Functional
Safety level is achieved due to various integrated diagnostic functions.
The CUR 423x is qualified according to AEC-Q100 and is designed for
automotive applications with temperatures ranging from –40 °C to +170 °C

TDK will present its Micronas CUR 423x sensors simultaneously from June
25 to 27, 2019 at the Sensor+Test fair in Nuremberg, Germany, at booth
204 in hall 1 and at the Sensors Expo in San Jose, California, at booth


  • TMR = Tunnel Magneto Resistance
  • SENT = Single-Edge Nibble Transmission
  • xEV = Vehicles including an electric traction motor
  • SPI = Serial Peripherals Interface
  • TSSOP = Thin Shrink Small Outline Package

Main applications

  • xEV Battery Monitoring
  • Stationary Battery Management

Main features and benefits

  • High-precision closed-loop and coreless TMR sensor technology (reduced
    system size and weight)
  • Contactless current sensing (non-intrusive)
  • Functional Safety diagnostic (ISO26262 ASIL-B ready)
  • Various programmable magnetic field ranges
  • Supply voltage protection up to 18 V
  • Automotive temperature grade (TJmax = 170 °C)
  • Various output interfaces (SENT acc. to SAEJ2716 Rev.4, full
    ratiometric Analog or SPI)

Key data

Type       CUR 423x
Package       TSSOP16
Output formats       SENT acc. to SAEJ2716 rev.4 (including fast 16 bit data channel),
SPI, full ratiometric analog (13 bit DAC)
Overall accuracy       Measurement error <1% of full-scale range
Flux density amplitude range       ±7 mT, ±40 mT
Functional Safety       ASIL-B ready (digital interface)
Temperature Range       TJ = –40 °C to 170 °C
Sample availability       Q4/2019

About TDK Corporation

TDK Corporation is a leading electronics company based in Tokyo, Japan.
It was established in 1935 to commercialize ferrite, a key material in
electronic and magnetic products. TDK’s comprehensive portfolio features
passive components such as ceramic, aluminum electrolytic and film
capacitors, as well as magnetics, high-frequency, and piezo and
protection devices. The product spectrum also includes sensors and
sensor systems such as temperature and pressure, magnetic, and MEMS
sensors. In addition, TDK provides power supplies and energy devices,
magnetic heads and more. These products are marketed under the product
brands TDK, EPCOS, InvenSense, Micronas, Tronics and TDK-Lambda. TDK
focuses on demanding markets in the areas of information and
communication technology automotive, industrial, and consumer
electronics. The company has a network of design and manufacturing
locations and sales offices in Asia, Europe, and in North and South
America. In fiscal 2019, TDK posted total sales of USD 12.5 billion and
employed about 105,000 people worldwide.

About TDK-Micronas

TDK-Micronas is the most preferred partner for sensing and control.
TDK-Micronas serves all major automotive electronics customers
worldwide, many of them in long-term partnerships for lasting success.
Operational headquarters are based in Freiburg im Breisgau (Germany).
Currently, TDK-Micronas employs around 1,000 persons. For more
information about TDK-Micronas and its products, please visit

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Further information on the products can be found under


Ms. Julia ANDRIS
Freiburg, Germany
+49 761
517 2531
[email protected]

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