Datasheet

MAX3140
SPI/MICROWIRE-Compatible UART with Integrated
True Fail-Safe RS-485/RS-422 Transceivers
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R
R
Y
Z
V
OD
V
OC
Figure 1. Driver DC Test Load
RECEIVER
OUTPUT
TEST POINT
1k
1k
S1
S2
V
CC
C
L
15pF
Figure 2. Receiver Enable/Disable Timing Test Load
DI
DE
V
CC
Y
Z
C
L1
C
L2
R
DIFF
V
ID
Figure 3. Driver Timing Test Circuit
OUTPUT
UNDER TEST
500Ω
S1
S2
V
CC
C
L
Figure 4. Driver Enable/Disable Timing Test Load
DI
3V
0
Z
Y
V
O
0
-V
O
V
O
1.5V
t
PLH
1/2 V
O
10%
t
R
90%
90%
t
PHL
1.5V
1/2 V
O
10%
t
F
V
DIFF
= V (Y) - V (Z)
V
DIFF
t
SKEW = |
t
PLH
- t
PHL |
Figure 5. Driver Propagation Delays
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0
Y, Z
V
OL
Y, Z
0
1.5V 1.5V
V
OL
+0.5V
V
OH
-0.5V
2.3V
2.3V
t
ZL(SHDN)
, t
ZL
t
LZ
t
ZH(SHDN)
, t
ZH
t
HZ
DE
Figure 6. Driver Enable and Disable Times