MC33288DH MOTOROLA [Motorola, Inc], MC33288DH Datasheet - Page 7

• Manufacturer Part Number: MC33288DH
• Description: Solid State Relay for Automotive Flasher Applications
• Manufacturer: MOTOROLA [Motorola, Inc]

package indended to be soldered directly on the Printed
Circuit Board.
JESD22-A113-B and J-STD-020A with the reflow conditions
applicable for packages with thickness above 2.5mm :
should not exceed 220°C (+5°C/-0°C). The time at maximum
temperature should range from 10 to 40s max.
maximum. The junction to ambient thermal resistance is
dependent on the mounting technology and the addition of
heat sink. One of the most commonly used mounting
technique consists in using the printed circuit board and the
copper lines as heat sink.
It has a total of 10cm
on the top side and 7.5 cm
of 25°C/W can be achieved, this value being splitted into :
thicker copper metal, higher number of thermal via from top to
down side pcb and the use of additional thermal via from the
circuit board to the module case.
Steady State Thermal Model
mounted on a printed circuit board can be splitted into two
main parts : junction to case and case to ambient resistances.
The maximum peak temperature during the soldering process
Soldering Information
Thermal Management
Figure 1. Printed Board Layout Example (not to scale)
This device is packaged in a Surface Mount Power
This device was qualified according to JEDEC standards
Convection 220°C +5/-0°C
VPR 215-219°C
IR / Convection 220°C +5/-0°C
The junction to case thermal resistance is 2°C/W
Figure 1 shows an example of printed circuit board layout.
With the above layout, thermal resistance junction to ambient
• junction to case : Rthjc1 = Rthjc2 = 2°C/W
• case to ambient : Rthca = 23 °C/W.
Lower value can be reached with the help of larger and
The junction to ambient thermal resistance of the circuit
A simplified steady state model is shown in figure 2.
top to down
HSOP20
Down side pcb
Thermal
side pcb
via from
8 cm
2
2
additional copper on two sides (2.5 cm
external pcb (4x4 cm)
2
on the down side).
Solid State Relay for Automotive Flasher Applications
Freescale Semiconductor, Inc.
For More Information On This Product,
Top side pcb
2 cm
2
Go to: www.freescale.com
MC33288
2
Transient Thermal Model
A more complete model including thermal capacitance is
proposed in figure 3.
This gives a thermal impedance versus time (figure 4), which
has been determined with the printed circuit board shown in
figure 1.
This figure shows that the steady state is reached after about
10 minutes. It also clearly shows that the device can dissipate
almost twice the power within one minute compared to the
maximum allowed power dissipation in steady state.
Figure 2.
30
20
10
0
Figure 4. Junction to ambiant Thermal impedance
0
Power Dissipation)
5mJ/K
450K/W
(1.0A=1W of
Ambiant
100
Power (W)
MOS1
0.5J/K
Surface Temperature)
Chan 1
(Volts represent Die
Figure 3. Transient thermal model
Simplified Thermal Model (Electrical Equivalent)
Chan 1 Junction
Temp Node
200
3K/W
3K/W
(1.0Ω=1°C/W)
(1.0V=1°C)
5mJ/K
20K/W
Board
300
Rthca
25°C/W
Chan 1
Switch
2°C/W
Time (sec.)
Rthjc1
MOS2
3K/W
Case
3K/W
400
1mJ/K
Case Temp Node
Ambient Temp Node
500
MOS3
AmbientTemperature
6J/K
Chan 2 Junction
Temp Node
Chan 2
Switch
2°C/W
3.5K/W
Rthjc2
3.5K/W
600
4mJ/K
300K/W
700
Power (W)
Chan 2
Control
800
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