Datasheet

TMC2300 DATASHEET (Rev. 1.02 / 2019-NOV-06) 13
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3.3 Highly Efficient Driver
The TMC2300 integrates a highly efficient power stage, offering low RDSon even at low supply
voltages, due to its internal charge pump. This enables high motor current drive capability and low
power dissipation for battery powered applications.
Figure 3.3 RDSon Variation over Supply Voltage
When operating at a high motor current, the driver power dissipation due to MOSFET switch on-
resistance significantly heats up the driver. This power dissipation will significantly heat up the PCB
cooling infrastructure, if operated at an increased duty cycle. This in turn leads to a further increase of
driver temperature. An increase of temperature by about 100°C increases MOSFET resistance by
roughly 50%. This is a typical behavior of MOSFET switches. Therefore, under high duty cycle, high
load conditions, thermal characteristics have to be carefully taken into account, especially when
increased environment temperatures are to be supported. Refer the thermal characteristics and the
layout hints for more information. As a thumb rule, thermal properties of the PCB design become
critical for the tiny QFN 3mm x 3mm package at or above 0.8A RMS motor current for increased
periods of time. For currents above 0.8A, a 4-layer PCB layout with 5 via contact of the die attach pad
to the GND plane is required. Keep in mind that resistive power dissipation raises with the square of
the motor current. On the other hand, this means that a small reduction of motor current significantly
saves heat dissipation and energy.
Pay special attention to good thermal properties of your PCB layout, when going for 0.8A RMS current
or more.
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RDSon vs. VS
RDSon (LS) [mOhm] RDSon(HS) [mOhm]