TH8056KDCA MELEXIS [Melexis Microelectronic Systems], TH8056KDCA Datasheet - Page 16

• Manufacturer Part Number: TH8056KDCA
• Description: Enhanced Single Wire CAN Transceiver
• Manufacturer: MELEXIS [Melexis Microelectronic Systems]

Assumptions:
Computations:
The above calculation shows that under worst case conditions (max. operating voltage, max bus load, max
ambient temperature) the TH8056 with the thermally enhanced SOIC14 package operates below the thermal
limit. A stable functioning is possible up to these limits.
3.9.1. Thermal behaviour of TH8056 with SOIC8 – TH8056 KDC A8
The thermal impedance of an SOIC8 package is about twice in comparison to the thermally enhanced
SOIC14 package. Therefore the maximum power dissipation within this package is only about the half.
The using of the SOIC8 version of TH8056 depends on the network architecture (number of nodes), the
max. ambient temperature and the needed functionality (using of INH pin).
The following diagram shows the relationship between junction temperature, ambient temperature and
number of nodes, which have to be taken into account for using the SOIC8 version.
TH8056 – Datasheet
3901008056
V
R
Network with 32 nodes
V
I
D = 50%
T
Θ
R
I
P
P
P
P
T
BAT
load
a
j
BAT
CANH
load
INT_a
INT_P
tot
load
JA
load_net
= 125°C + 426mW * 70k/W = 155°C
= 125°C
160
150
140
130
120
110
100
= 267mW + 159mW = 426mW
= 6mA
= 70k/W (Thermally enhanced SOIC14 package)
= 5.1V / 203Ω = 25mA
90
80
= 5.1V * 25mA * 0.5 = 64mW
= 26.5V
= 6.49 kΩ
= (26.5V – 5.1V) * 25mA * 0.5 = 267mW
= 5.1V
= 26.5V * 6mA = 159mW
2
= 6.49kΩ / 32nodes = 203Ω
4
U
BAT
6
Figure 7 – Save operating area of SOIC8 package
U
= 26.5V; T
BAT
= 26.5V; T
8
a
= 125°C
10
a
= 85°C
12
Number of Network Nodes
U
Page 16 of 26
BAT
14
Enhanced Single Wire CAN Transceiver
= 18V; T
16
U
BAT
a
= 105°C
= 18V; T
18
U
BAT
a
20
= 125°C
= 26.5V; T
22
a
= 105°C
Save Operating Area
24
SOIC8 Package
26
TH8056
28
30
March 2007
32
Rev 012