Datasheet

TMC2209 DATASHEET (Rev. 1.03 / 2019-JUN-26) 77
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20.3 Thermal Characteristics
The following table shall give an idea on the thermal resistance of the package. The thermal
resistance for a four-layer board will provide a good idea on a typical application. Actual thermal
characteristics will depend on the PCB layout, PCB type and PCB size. The thermal resistance will
benefit from thicker CU (inner) layers for spreading heat horizontally within the PCB. Also, air flow will
reduce thermal resistance.
A thermal resistance of 30K/W for a typical board means, that the package is capable of continuously
dissipating 3.3W at an ambient temperature of 25°C with the die temperature staying below 125°C.
Note, that a thermally optimized layout is required.
Parameter
Symbol
Conditions
Typ
Unit
Typical power dissipation
P
D
StealthChop or SpreadCycle, 1.4A RMS
in two phase motor, sinewave, 40 or
20kHz chopper, 24V, 90°C peak surface
of package (motor QSH4218-035-10-
027, short time operation)
2.8
W
Typical power dissipation
P
D
StealthChop or SpreadCycle, 1.0A RMS
in two phase motor, sinewave, 40 or
20kHz chopper, 24V, 70°C peak surface
of package (motor QSH4218-035-10-
027)
1.4
W
Thermal resistance junction to
ambient on a multilayer board
QFN28
R
TMJA
Dual signal and two internal power
plane board (2s2p) as defined in
JEDEC EIA JESD51-5 and JESD51-7
(FR4, 35µm CU, 70mm x 133mm,
d=1.5mm)
30
K/W
Thermal resistance junction to
case
R
TJC
Junction to heat slug of package
6
K/W
Table 20.1 Thermal characteristics TMC2209
Note
A spread-sheet for calculating TMC2209 power dissipation is available on www.trinamic.com.