April 12, 2020 by Abdulwaliy Oyekunle
The TMCS1101 isolated current sensor is a hall-effect sensor used for AC or DC current sensing and measurements. It features a body size of 4.90 mm by 3.90 mm and packaged in an 8-pin SOIC package IC.
The product is a galvanically isolated hall-effect current sensor. It provides current sensing in a unidirectional and bidirectional linear way. Being a hall-effect current sensor, a magnetic field is generated when current flows through the isolated side of the device.
At room temperature, low power is dissipated as the device has a low-ohmic lead frame path made up of copper. The lead frame has a nominal resistance of 1.8mΩ.
Also, the TMCS1101 has multiple sensitivity options ranging from 50mV/A to 400mV/A. The sensitivity error is about ±0.3%. It has an offset error and offset current drift of ±12.5mA and 0.02mA/°C respectively. The full-scale error of the product is less than 1.5%.
A product reference image of the TMCS1101.
The product is power efficient as it operates with an analogue input supply voltage ranging from 3V to 5.5V. It also features a 600V basic isolation working DC voltage. It supports a signal bandwidth of 80KHz.
The device also supports a maximum input current of 20A. The galvanic insulation provides a 3000V dielectric withstand isolation between the current path and circuitry. The recommended working temperature range of the product is −40°C to +125°C.
With zero drift internal reference, offset errors are minimised and the system-level performance is increased which leads to high accuracy in measurements. This high accuracy allows the component to measure current up to 400A.
The TMCS1101 is packaged in an SOIC package with 8 pins. It has a power supply and a ground pin. It also has 2 input current positive pins and 2 input current negative pins. The output of the device is taken from the output voltage pin.
As a good analogue design practice, a decoupling capacitor (0.1µF is a good choice) is required between the power supply pin and the ground pin.
A diagram of the hall effect current sensors, which measures the magnetic field generated as current flows in the conductor. Image Credit: Texas Instruments
Having a 600V basic isolation working voltage makes the product to be safe to use as it is VDE 0884-11 certified.
Unlike the TMCS1101 which is a hall-effect current sensor, INA250—also manufactured by Texas Instruments—is a shunt resistor current sensor. INA250 has a sensitivity that varies from 200mV/A to 2V/A. It finds applications in test equipment, power management, and inverters.
A diagram displaying the pin description of the product. The I/O pins are analogue. Image Credit: Texas Instruments
The TMCS1101 has a wide range of applications in electrical circuit designs such as motor and load control. The unidirectional and bidirectional current sensing makes it possible for engineers to use the device to monitor AC and DC power. It can also be used for power factor correction and over current protection.
The component is largely used where isolated current measurement is required in circuit designs. One key advantage of using the product in design is that multipoint calibration is eliminated due to its accuracy and low-temperature drift. The operating voltage supply range makes it possible for use in applications that require a wide range of voltage levels.
