L6228 STMicroelectronics, L6228 Datasheet - Page 21

• Manufacturer Part Number: L6228
• Description: DMOS DRIVER FOR BIPOLAR STEPPER MOTOR
• Manufacturer: STMicroelectronics

Figure 26. IC Power Dissipation versus Output Current in WAVE Mode (full step one phase on).
Figure 27. IC Power Dissipation versus Output Current in MICROSTEPPING Mode.
Thermal Management
In most applications the power dissipation in the IC is the main factor that sets the maximum current that can
be delivered by the device in a safe operating condition. Therefore, it has to be taken into account very carefully.
Besides the available space on the PCB, the right package should be chosen considering the power dissipation.
Heat sinking can be achieved using copper on the PCB with proper area and thickness. Figures 28, 29 and 30
show the Junction-to-Ambient Thermal Resistance values for the PowerSO36, PowerDIP24 and SO24 packag-
es.
For instance, using a PowerSO package with copper slug soldered on a 1.5mm copper thickness FR4 board
with 6cm
ing methods for this package. Using a multi-layer board with vias to a ground plane, thermal impedance can be
reduced down to 15°C/W.
2
dissipating footprint (copper thickness of 35µm), the R
P
D
[W]
P
D
[W]
10
8
6
4
2
0
10
0
8
6
4
2
0
0 0.25 0.5 0.75 1 1.25 1.5
0.25 0.5 0.75 1
WAVE DRIVE
MICROSTEPPING
I
OUT
I
OUT
[A]
[A]
1.25 1.5
I
I
A
B
I
I
A
B
Test Conditions:
Supply Voltage = 24V
th(j-amb)
f
f
SW
SW
Test Conditions:
Supply Voltage = 24V
= 30 k Hz (slow decay)
= 50 k Hz (slow decay)
I
OUT
is about 35°C/W. Fig. 31 shows mount-
I
OUT
No PW M
f
SW
= 3 0 kHz (slow decay)
I
OUT
I
OUT
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