Product description:
The CDT series is the LEM RCM type B current sensor family designed to measure and protect from AC and DC fault current (leakage current), dedicated to automotive applications. Our proprietary fluxgate architecture allows the sensor to have best in class accuracy hence protection from potential fire hazards and electrical shocks. The package is configurable up to 4 conductors 48Arms capable, allowing 1 and 3 phases systems and offering an optimized leakage measurement of configurations by design. The CDT series sensors provide a tripping fault current output and an SPI bus enabling fast response time and detailed fault information. For automotive applications, such as bidirectional On-Board Chargers, an ISO26262 ASIL B compliant version offers additional safety diagnostics.
Measurement principle:
In a stable system the sum of current (phase and neutral) flowing in conductors is null, when a fault occurs, a difference is measured between phase and neutral conductors. This difference represents the leakage current typically caused by a loss of insulation from a conductor to the earth.
Main Features & Advantages
• Automotive qualified (AEC-Q100 and 200 components) Up to 48 A RMS current per primary conductor . Primary current measurement range: ±300 mA DC . External test via dedicated pin . SPI and digital tripping outputs . Compact design for PCB mounting . Excellent accuracy . Fast Tripping . Reinforced galvanic insulation. .
Typical applications
Developed for, EV On Board Charger: • Automotive OBC up to 22 kW (V2L, V2G, V2H) Compatible with, Off board Charging: Mode 2: In Cord – Control and Protection Device . (IC-CPD) • Mode 3: Wall box chargers Functional safety (SF version only) • ISO26262 ASIL B: refer to safety manual. EMC Compatible standards: * • IEC 61851-21: 2017 Fault current tripping according to: * ●   IEC 62752: 2016 and UL 2231: 2012 *Complete list of reference standards available in safety manual Page 1 of 18 Sensor Selection Table The following table summarizes the configuration of the product:
1) The SPI Interface is not required, the fault current tripping signal is available via the dedicated tripping pin, see Sensor Pin Out. SPI is only required for ASIL B ISO26262 metrics compliance.
Sensor Pin Out (TOP VIEW)

Sensor Internal Architecture
Page 3 of 18 LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com

Absolute maximum ratings ²) 3)

Notes:
1) The design of customer PCB tracks (width & thickness) and the LEM transducer's primary jumpers can influence each other regarding thermal exchanges and self-heating. Customer remains responsible for thermal design. ²² Absolute maximum ratings apply at 25 °C unless otherwise noted. 31 Exposure to absolute maximum ratings for extended periods of time may affect reliability.
General electrical ratings

Notes: 1) Tripping variants xCDT-IEC6m xCDT-UL5m ²² Tripping variants xCDT-IEC30m xCDT-IEC20m xCDT-UL20m 3) This value is calculated using IEC 62380 Standard and sensor ambient temperature profile of 73 °C. It is a FIT value with no safety mechanism applied. ISO 26262 PMHF is lower and compatible with ASIL-B metrics. Page 4 of 18 LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com
Notes: thermal improvement.
Low voltage circuits are intended to be powered by a circuit derived from an isolating source (such as a transformer, optical isolator, limiting impedance or electro-mechanical relay) and having no direct connection back to the primary circuit (other than through the grounding means). Page 5 of 18 www.lem.com
Notes: +/- 10 KHz.
Performance Parameters Definition
Definition of typical, minimum and maximum values
Minimum and maximum values for specified limiting and safety conditions must be understood as such as well as values shown in "typical" graphs. On the other hand, measured values are part of a statistical distribution that can be specified by an interval with upper and lower limits and a probability for measured values to lie within this interval. Unless otherwise stated (e.g. "100 % tested"), the LEM definition for such intervals designated with "min" and "max" is that the probability for values of samples to lie in this interval is 99.73 %. For a normal (Gaussian) distribution, this corresponds to an interval between −3 sigma and +3 sigma. If "typical" values are not obviously mean or average values, those values are defined to delimit intervals with a probability of 68.27 %, corresponding to an interval between −sigma and +sigma for a normal distribution. Typical, maximal, and minimal values are determined during the initial characterization of the product.
Sensor Application Notes
xCDT sensor Application note reference PDM number includes information that will ensure robust integration of the sensor in customer application (test set-up, magnetic environment...). SPI Technical Specification reference PDM number detail the Serial Peripheral Interface protocol to be implemented by the customer to communicate with the sensor. The latest version of these documents can be downloaded from LEM Website. Page 7 of 18

Correct Sensor Integration inside Power Converters regarding EMC constraints
The differential transducer placement inside client application, typically in a car onboard charger, must be chosen to minimize EMC interferences. It shall be located after surge absorbers at position 4 to 5. Other positioning may degrade the performance of the sensor. The sensor is sensitive to aliasing phenomena on high frequency content (>10 kHz) which shall be minimized on the customer side.
Test Winding Low Frequency Sensing Element Design rules
Customer test winding driving circuit for low frequency sensor element must be designed carefully to avoid interactions with the sensor. It must behave as a perfect current source while injecting current and shall be floating while unused.
Sensor typical interface
See Application Note for details on values of components. Page 8 of 18

Tripping Pin and SPI TRIP Signal
The tripping pin and SPI TRIP signal are used to indicate that a fault current has been detected. In such condition, the pin goes to LOW and the SPI signal goes to high whether AC or DC tripping occurred, or in a situation when the sensor is not operational. During startup, the TRIP pin is set-up in high impedance and requires a pull-down resistor for safe operation. Please refer to the safety manual for detailed description of "safe state" according to ISO26262.
Tripping timing diagram
The tripping signal will operate as follows: The Fault tripping time of LEM sensor only includes the delay related to the measurement of leakage current but does not comprise additional delay related to customer electronic circuit (control circuit of relay, relay opening time…). On following graphs, the red dashed curve shows the tripping characteristic required by the norm and the blue curve gives you the theorical tripping time programmed in the sensor software. To consider measurement tolerance, customer can include a maximum LEM actual tripping time variation of +/- 30 % compared to theorical blue curve on short tripping time. Overcurrent specifications: For a primary peak current ( l ρ R u ) above |300|mA the typical tripping time is 500us. Page 9 of 18 LEM International SA
Page 10 of 18 LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com
Page 11 of 18 LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com Page 12 of 18 LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com The absolute error of the sensor measurement channels versus voltage supply is given as follows (data extract DV test results 01/2023): Page 13 of 18
Dimensions CDT 0.3-S2, CDT-SF 0.3-S2, CDT 0.3-S4, CDT-SF 0.3-S4 (in mm) - Date code + LEM or Customer P/N - Date code: PYYDDDCCHHMMSSJ (See detalls on notas) Page 14 of 18 LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com CDT-SF xxx-S2 Page 15 of 18 LEM reserves the right to carry out modifications on its transducers to improve them. LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com Page 16 of 18 LEM International SA Route du Nant-d'Avril, 152 1217 Meyrin www.lem.com
Mechanical characteristics
Plastic case . Mass . - CDT-SF 0.3-S2 - CDT-SF 0.3-S4 Primary conductor material . Electrical terminal coating . Degrees of protection provided by enclosure . Connector type . Soldering type . Soldering profile . Recommended PCB thickness . Mandatory screws for the 2 fixing holes
PA66-GF25
33 g 41 g EN CW004A Cu-etp Nickel + Matte Tin Plating IP40 Through Hole Wave or selective wave Maximum TBD °C, 10 s 1.6 mm DELTA PT Ø 2.5 x 8 mm INOX A2 or equivalent non-magnetic steel Fastening torque = 0.6 ±0.1 N m.
Assembly recommendations
When installed in the end-use equipment, consideration shall be given to the following: The sensor shall be assembled in industrials ESD protected environment. These devices are intended to be mounted on the printed wiring board of the end-use equipment. Page 17 of 18
Caution If the device is used in a way that is not specified by the manufacturer, the protection provided by the device may be compromised. Always inspect the electronics unit and connecting cable before using this product and do not use it if damaged. Mounting assembly shall guarantee the maximum primary conductor temperature, fulfill clearance and creepage distance, minimize electric and magnetic coupling, and unless otherwise specified can be mounted in any orientation. Caution, risk of electrical shock This transducer must be used in limited-energy secondary circuits SELV according to IEC 61010-1, in electric/electronic equipment with respect to applicable standards and safety requirements in accordance with the manufacturer's operating specifications. Use caution during installation and use of this product; certain parts of the module can carry hazardous voltages and high currents (e.g., power supply, primary conductor). Ignoring this warning can lead to injury and or/or cause serious damage. If applicable: De-energize all circuits and hazardous live parts before installing the product. All installations, maintenance, servicing operations and use must be carried out by trained and qualified personnel practicing applicable safety precautions. This transducer is a build-in device, whose hazardous live parts must be inaccessible after installation. This transducer must be mounted in a suitable end-enclosure. Besides make sure to have minimum 30 mm between the primary terminals of the transducer and other neighboring components. If applicable: Main supply must be able to be disconnected. If applicable: Always inspect the flexible probe for damage before using this product. If applicable: Never connect or disconnect the external power supply while the primary circuit is connected to live parts. If applicable: Never connect the output to any equipment with a common mode voltage to earth greater than 30 V. If applicable: Always wear protective clothing and gloves if hazardous live parts are present in the installation where the measurement is carried out. This transducer is a built-in device, not intended to be cleaned with any product. Nevertheless, if the user must implement cleaning or washing process, validation of the cleaning program has to be done by himself. If applicable: When defining soldering process, please use no cleaning process only. At the ESD susceptibility The product is susceptible to be damaged from an ESD event and the personnel should be grounded when handling it. Do not dispose of this product as unsorted municipal waste. Contact a qualified recycler for disposal. If CE marking not applicable: Although LEM applies utmost care to facilitate compliance of end products with applicable regulations during LEM product design, use of this part may need additional measures on the application side for compliance with regulations regarding EMC and protection against electric shock. Therefore, LEM cannot be held liable for any potential hazards, damages, injuries or loss of life resulting from the use of this product. Underwriters Laboratory Inc. recognized component
Version history

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