Datasheet
TMC2209 DATASHEET (Rev. 1.03 / 2019-JUN-26) 13
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While the standard application circuit is limited to roughly 5.2 V lower supply voltage, a 5 V only
application lets the IC run from a 5 V +/-5% supply. In this application, linear regulator drop must be
minimized. Therefore, the internal 5V regulator is filtered with a higher capacitance. An optional
resistor bridges the internal 5V regulator by connecting 5VOUT to the external power supply. This RC
filter keeps chopper ripple away from 5VOUT. With this resistor, the external supply is the reference
for the absolute motor current and must not exceed 5.5V. Standby function will not work in this
application, because the 5V regulator is bridged.
3.4 Configuration Pins
The TMC2209 provides four configuration pins. These pins allow quick configuration for standalone
operation. Several additional options can be set by OTP programming. In UART mode, the
configuration pins can be disabled in order to set a different configuration via registers.
PDN_UART: CONFIGURATION OF STANDSTILL POWER DOWN
PDN_UART
Current Setting
GND
Enable automatic power down in standstill periods
VCC_IO
Disable
UART interface
When using the UART interface, the configuration pin should be disabled via
GCONF.pdn_disable = 1. Program IHOLD as desired for standstill periods.
MS1/MS2: CONFIGURATION OF MICROSTEP RESOLUTION FOR STEP INPUT
MS2
MS1
Microstep Setting
GND
GND
8 microsteps
GND
VCC_IO
32 microsteps (different to TMC2208!)
VCC_IO
GND
64 microsteps (different to TMC2208!)
VCC_IO
VCC_IO
16 microsteps
SPREAD: SELECTION OF CHOPPER MODE
SPREAD
Chopper Setting
GND or
Pin open / not
available
StealthChop is selected. Automatic switching to SpreadCycle in dependence of
the step frequency can be programmed via OTP.
VCC_IO
SpreadCycle operation.
3.5 High Motor Current
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 5mm x 5mm package at or above 1.4A RMS motor current for increased
periods of time. Keep in mind that resistive power dissipation rises 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 1.4A RMS current
or more.