Datasheet

PCA9601 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 6 May 2011 23 of 32
NXP Semiconductors
PCA9601
Dual bidirectional bus buffer
Question: If we add 100 Ω to 200 Ω at signal line, the overshoot becomes slightly
smaller. Is this a good idea?
Answer: No, it is not necessary to add any resistance. When the logic signal generated
by TX or TY of PCA9601 drives long traces or wiring with ICs other than PCA9601
being driven, then adding a Schottky diode (BAT54A) as shown in Figure 26
will clamp
the wiring undershoot to a value that will not cause conduction of the IC’s internal
diodes.
Fig 26. Wiring transients limited by a Schottky diode
002aaf080
time (ns)
2
0
4
6
voltage
(V)
−2
horizontal scale = 62.5 ns/div
receive
5 V
RX
TX
SX
PCA9601
send
300 Ω
5 V
2 meter
cable
5 V
300 Ω
GND
receive
SX
RX
TX
5 V
send
1
/
2
BAT54A