Datasheet

9
LTC1334
TEST CIRCUITS
Figure 2. RS485 Driver/Receiver
Timing Test Circuit
Figure 1. RS422/RS485
Driver Test Load
R
R
V
OD
Y
Z
LTC1334 • F01
V
OC
R
L
C
L
LTC1334 • F02
Y
3V
3V
SEL
DE
Z
C
L
A
SEL
3V
R
B
15pF
D
DR OUT
C
L
500Ω
S2
LTC1334 • F03
V
CC
S1
Figure 4. RS232 Driver
Swing/Timing Test Circuit
R
L
LTC1334 • F04
Y, Z
0V
SEL
D
C
L
Figure 5. RS232 Receiver
Timing Test Circuit
SWITCHI G WAVEFOR S
U
W
Figure 3. RS485 Driver Output
Enable/Disable Timing Test Load
1.5V
3V
0V
D
f = 1MHz: t
r
≤ 10ns: t
f
≤ 10ns
1.5V
Z – Y
–V
O
V
O
t
SKEW
1/2 V
O
LTC1334 • F06
t
PLH
t
r
90%
50%
10%
t
PHL
t
f
90%
50%
10%
V
O
t
SKEW
V
DIFF
= V(Z) – V(Y)
Z
Y
Figure 6. RS485 Driver Propagation Delays
LTC1334 • F05
15pF
Y, Z
0V
SEL
D
R
0V
SEL
A, B
V
IN
V
OUT