Datasheet

6
LTC1685
FU CTIO TABLES
U
U
Transmitting
INPUTS LINE OUTPUTS
RE DE DI CONDITION B A
X 1 1 No Fault 0 1
X 1 0 No Fault 1 0
X 0 X X Hi-Z Hi-Z
X 1 X Fault
Receiving
INPUTS OUTPUT
RE DE A – B RO
00 ≥ 300mV 1
00 ≤ –300mV 0
0 0 Inputs Open 1
0 0 Inputs Shorted Together 1
A = B = –7V to 12V
1X X Hi-Z
±10mA Current Source
TEST CIRCUITS
V
OD
A
B
R
R
V
OC
1685 F01
Figure 1. Driver DC Test Load
RECEIVER
OUTPUT
C
L
15pF
1k
S1
S2
TEST POINT
V
DD
1k
1685 F02
Figure 2. Driver DC Test Load
OUTPUT
UNDER TEST
C
L
S1
S2
V
DD
500Ω
1685 F04
Figure 3. Driver/Receiver Timing Test Circuit Figure 4. Driver Timing Test Load #2
3V
DE
A
B
DI
R
DIFF
C
L1
C
L2
RO
15pF
A
B
RE
1685 F03