SN65HVD230
SN65HVD231
SN65HVD232
SLOS346G – MARCH 2001 – REVISED JUNE 2002
APPLICATION INFORMATION
high-speed (continued)
1 Mbps
Driver Output
NRZ Data
1
Figure 31. Typical High Speed SN65HVD230 Output Waveform Into a 60-Ω Load
slope control
Electromagnetic compatibility is essential in many applications using unshielded bus cable to reduce system
cost. To reduce the electromagnetic interference generated by fast rise times and resulting harmonics, the rise
and fall slopes of the SN65HVD230 and SN65HVD231 driver outputs can be adjusted by connecting a resistor
from R (pin 8) to ground or to a logic low voltage, as shown in Figure 32. The slope of the driver output signal
S
is proportional to the pin’s output current. This slope control is implemented with an external resistor value of
10 kΩ to achieve a ≈ 15 V/µs slew rate, and up to 100 kΩ to achieve a ≈ 2.0 V/µs slew rate as displayed in
Figure 33. Typicaldriveroutputwaveformsfromapulseinputsignalwithandwithoutslopecontrolaredisplayed
in Figure 34. A pulse input is used rather than NRZ data to clearly display the actual slew rate.
10 kΩ
to
100 kΩ
R
S
IOPF6
D
1
2
3
4
8
7
6
5
TMS320LF2406
or
TMS320LF2407
GND
CANH
CANL
V
CC
R
V
ref
Figure 32. Slope Control/Standby Connection to a DSP
22
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