1

IN+

8

VS

2

IN+

7

VOUT

3

IN±

6

NC

4

IN±

5

GND

}

}

26

TMCS1101

SBOS825 – SEPTEMBER 2019

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Product Folder Links: TMCS1101

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Copyright © 2019, Texas Instruments Incorporated

11 Power Supply Recommendations

is derived from VS using a resistor divider; therefore, tale care to optimize the power supply path for both noise

and stability across temperature to provide the highest precision measurement. To filter noise in the power-

the supply and ground pins of the device. To compensate for noisy or high-impedance power supplies, add more

decoupling capacitance.

12 Layout

12.1 Layout Guidelines

The TMCS1101 is specified for a continuous current handling capability of 20-A across the full ambient

temperature range of –40°C to +125°C on the TMCS1100EVM, which uses 3-oz copper pour planes. This

current capability is fundamentally limited by the maximum device junction temperature and the thermal

environment, primarily the PCB layout and design. To maximize current-handling capability and thermal stability

of the device, take care with PCB layout and construction to optimize the thermal capability. Efforts to improve

the thermal performance beyond the design and construction of the TMCS1100EVM can result in increased

continuous-current capability due to higher heat transfer to the ambient environment. Keys to improving thermal

performance of the PCB include:

•

Use large copper planes for both input current path and isolated power planes and signals.

•

Use heavier copper PCB construction.

•

Place thermal via farms around the isolated current input.

•

Provide airflow across the surface of the PCB.

The TMCS1101 senses external magnetic fields, so make sure to minimize adjacent high-current traces in close

proximity to the device. The input current trace can contribute additional magnetic field to the sensor if the input

current traces are routed parallel to the vertical axis of the package. Figure 15 illustrates the most optimal input

current routing into the TMCS1101. As the angle that the current approaches the device deviates from 0° to the

horizontal axis, the current trace contributes some additional magnetic field to the sensor, increasing the effective

sensitivity of the device. If current must be routed parallel to the package vertical axis, move the routing away

from the package to minimize the impact to the sensitivity of the device. Terminate the input current path directly

underneath the package lead footprint, and use a merged copper input trace for both the IN+ and IN– inputs.

Figure 15. Magnetic Field Generated by Input Current Trace