TH8080 Datasheet, PDF (15/23 Pages) Melexis Microelectronic Systems – SoloLIN Transceiver

TH8080
SoloLIN Transceiver
5.3 Duty Cycle Calculation
TxD
V_SUP
100%
BUS
58.1%
28.4%
V_SS 0%
RxD
t_Bit
t_dom(max)
t_dom(min)
t_Bit
t_rec(min)
74.4%
42.2%
t_rec(max)
58.1%
28.4%
Figure 8 - Duty cycle calculation in accordance to LIN 2.0
With the timing parameters shown in Figure 8 two duty cycles , based on t_rec(min)
calculated as follows :
D1 = t_rec(min) / (2 * t_Bit)
D2 = t_rec(max) / (2 * t_Bit)
and t_rec(max)
can be
For proper operation at 20KBit/s ( t_Bit = 50µs) the LIN driver has to fulfil the duty cycles specified in chapter
2.4 Dynamic Characteristics for supply voltages of 7 to 18V and the defined standard loads .
Due to this simplified definition there is no need to measure slew rates, slope times, transmitter delays and
dominant voltage levels as specified in the LIN physical layer specification 1.3.
The device within the D1/D2 duty cycle range operates also in applications with reduced bus speed of
10.4KBit/s or below.
In order to minimize EME, the slew rates of the transmitter can be reduced (approximately by 2 times). Such
devices have to fulfil the duty cycle definition D3/D4 in the LIN physical layer specification 2.0. Devices within
this duty cycle range cannot operate in 20KBit/s applications.
TH8080 – Datasheet
3901008080
Page 15 of 23
July 2004
Rev 006