2-Phase Stepper Motor Unipolar Driver IC (2-Phase Excitation)
SMA7036M
sThermal Design
An outline of the method for calculating heat dissipation is
shown below.
(1) Obtain the value of PH that corresponds to the motor coil
current IO from Fig. 6 "Heat dissipation per phase PH vs. Out-
put current IO."
Fig. 6 Heat dissipation per phase PH vs. Output current IO
1.2
1.0
0.8
0.6
0.4
0.2
0
0
36V
VCC =44V
24V
Motor : 23LM-C004
15V Holding mode
0.2 0.4 0.6 0.8 1.0
Output current IO (A)
(2) The power dissipation Pdiss is obtained using the following
formula.
2-phase excitation: Pdiss ≅ 2PH+0.015×VS (W)
1-2 phase excitation: Pdiss ≅
3
2
PH+0.015×VS (W)
(3) Obtain the temperature rise that corresponds to the calcu-
lated value of Pdiss from Fig. 7 "Temperature rise."
Fig. 7 Temperature rise
150
∆Tj
100
∆TC Natural cooling
Without heatsink
50
0
0
1
2
3
4
Total Power (W)
Thermal characteristics
30
25
20
15
10
5
0
200
Without heatsink
Natural cooling
TC ( 4 pin)
Motor : PH265-01B
Motor current IO=0.8A
Ta=25°C
VCC=24V, VS=24V
2-phase excitation
500
1K
Response frequency (pps)
SMA7036M 17