Datasheet

5
LTC1487
sn1487 1487fs
DI (Pin 4): Driver Input. If the driver outputs are enabled
(DE HIGH) then a LOW on DI forces the outputs A LOW and
B HIGH. A HIGH on DI with the driver outputs enabled will
force A HIGH and B LOW.
GND (Pin 5): Ground.
A (Pin 6): Driver Output/Receiver Input.
B (Pin 7): Driver Output/Receiver Input.
V
CC
(Pin 8): Positive Supply. 4.75V < V
CC
< 5.25V.
PIN FUNCTIONS
UUU
RO (Pin 1): Receiver Output. If the receiver output is
enabled (RE LOW), and A > B by 200mV, RO will be HIGH.
If A < B by 200mV, then RO will be LOW.
RE (Pin 2): Receiver Output Enable. A LOW enables the
receiver output, RO. A HIGH input forces the receiver
output into a high impedance state.
DE (Pin 3): Driver Outputs Enable. A HIGH on DE enables
the driver output. A and B and the chip will function as a line
driver. A LOW input will force the driver outputs into a high
impedance state and the chip will function as a line
receiver. If RE is HIGH and DE is LOW, the part will enter
a low power (1µA) shutdown state.
Figure 3. Driver/Receiver Timing Test Circuit Figure 4. Driver Timing Test Load
OUTPUT
UNDER TEST
C
L
S1
S2
V
CC
500Ω
LTC1487 • F04
3V
DE
A
B
DI
R
DIFF
C
L1
C
L2
RO
15pF
A
B
RE
LTC1487 • F03
Figure 1. Driver DC Test Load Figure 2. Receiver Timing Test Load
V
OD
A
B
R
R
V
OC
LTC1487 • F01
RECEIVER
OUTPUT
C
RL
1k
S1
S2
TEST POINT
V
CC
1k
LTC1487 • F02
TEST CIRCUITS
LTC1487 Transmitting
INPUTS OUTPUTS
RE DE DI B A
X1101
X1010
00XZZ
1 0 X Z* Z*
*Shutdown mode
LTC1487 Receiving
INPUTS OUTPUTS
RE DE A – B RO
00≥0.2V 1
00≤–0.2V 0
0 0 Inputs Open 1
10 X Z*
*Shutdown mode
FU CTIO TABLES
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