Datasheet

9
LTC1482
FU CTIO TABLES
U
U
Driver Enabled (DE = 1)
DI/SHDN A B RO CD
00100
11010
X A Shorted to B 1 1
Driver Disabled (DE = 0, Notes 1, 2)
DI/SHDN A – B RO CD
0 X (Note 3) Z 1 (Internal Pull-Up)
1V
THCD(MIN)
< (A – B) < V
THCD(MAX)
11
1 A and B are Open 1 1
1 A and B are Shorted 1 1
1V
THCD(MIN)
≥ (A – B) ≥ V
THCD(MAX)
00
and (A – B) ≤ V
THRO(MIN)
1V
THCD(MIN)
≥ (A – B) ≥ V
THCD(MAX)
10
and (A – B) ≥ V
THRO(MAX)
X = Don’t Care
Z = High Impedance
Note 1: DE = 0, DI/SHDN = 0 puts the part in I
CC
shutdown and the supply
current drawn by the V
CC
pin drops to 20µA max. The receiver is always
alive except in shutdown.
Note 2: The table is valid regardless of the presence of an external
termination resistor.
Note 3: Although the RO and the driver outputs are three-stated, the A and
B pins each present a 22kΩ receiver input resistance to ground.
TEST CIRCUITS
RECEIVER
OUTPUT
C
L
1k
S1
S2
TEST POINT
V
CC
1k
1482 F03
V
OD
A
B
R
R
V
OC
1482 F01
Figure 1. Driver DC Test Load #1 Figure 3. Receiver Timing Test Load
V
OD3
A
B
375Ω
375Ω
60Ω
V
TST
–7V TO 12V
1482 F02
Figure 2. Driver DC Test Load #2
Figure 5. Driver Timing Test Load
OUTPUT
UNDER TEST
C
L
S1
S2
V
CC
500Ω
1482 F05
Figure 4. Driver/Receiver Timing Test Load
DE
A
B
DI
R
DIFF
V
CC
C
L1
C
L2
RO
CD
1k
15pF
A
B
1482 F04
(DE = 0, DI/SHDN = 0) or to disable the driver while keeping
the receiver alive (DE = 0, DI/SHDN = 1). When the driver
is enabled (DE = 1), DI/SHDN = 0 forces the A output low
and the B output high. DI/SHDN = 1 forces the A output
high and the B output low.
GND (Pin 5): Ground.
A (Pin 6): Driver Output/Receiver Input. The input resis-
tance is typically 22k when the driver is disabled (DE = 0).
When the driver is enabled, the A output follows the logic
level at the DI/SHDN pin.
B (Pin 7): Driver Output/Receiver Input. The input resis-
tance is typically 22k when the driver is disabled (DE = 0).
When the driver is enabled, the B output is inverted from
the logic level at the DI/SHDN pin.
V
CC
(Pin 8): Positive Supply. 4.75V < V
CC
< 5.25V. A 0.1µF
bypass capacitor is recommended.
PIN FUNCTIONS
UUU