ADM2485
TIMING SPECIFICATIONS
2.7 V ≤ V
DD1
≤ 5.5 V, 4.75 V ≤ V
DD2
≤ 5.25 V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Table 2.
Parameter
DRIVER
Maximum Data Rate
Propagation Delay Input-to-Output
t
PLH
, t
PHL
RTS-to-DE OUT Propagation Delay
Driver Output-to-Output, t
SKEW
Rise/Fall Time, t
R
, t
F
Enable Time
Disable Time
Enable Skew, |t
AZH
− t
BZL
|, |t
AZL
− t
BZH
|
Disable Skew, |t
AHZ
− t
BLZ
|, |t
ALZ
− t
BHZ
|
RECEIVER
Propagation Delay, t
PLH
, t
PHL
Differential Skew, t
SKEW
Enable Time
Disable Time
Min
16
25
20
45
35
2
5
43
43
1
2
25
45
3
3
55
55
5
15
53
55
3
5
55
5
13
13
Typ
Max
Unit
Mbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
R
LDIFF
= 54 Ω, C
L1
= C
L2
= 100 pF, see Figure 25
See Figure 26
R
LDIFF
= 54 Ω, C
L1
= C
L2
= 100 pF, see Figure 2 and Figure 25
R
LDIFF
= 54 Ω, C
L1
= C
L2
= 100 pF, see Figure 2 and Figure 25
See Figure 4 and Figure 27
See Figure 4 and Figure 27
See Figure 4 and Figure 27
See Figure 4 and Figure 27
C
L
= 15 pF, see Figure 3 and Figure 28
C
L
= 15 pF, see Figure 3 and Figure 28
R
L
= 1 kΩ, C
L
= 15 pF, see Figure 5 and Figure 29
R
L
= 1 kΩ, C
L
= 15 pF, see Figure 5 and Figure 29
Test Conditions/Comments
Timing Diagrams
3V
1.5V
0V
1.5V
t
PLH
B
1/2V
OUT
V
OUT
A
t
PHL
0.7V
DD1
RTS
0.5V
DD1
0.5V
DD1
t
ZL
t
SKEW
= |t
PLH
– t
PHL
|
90% POINT
90% POINT
t
LZ
2.3V
0.3V
DD1
+V
OUT
0V
–V
OUT
A–B
V
OH
+ 0.5V
10% POINT
10% POINT
06021-012
t
ZH
2.3V
t
HZ
V
OH
– 0.5V
V
OL
V
OH
06021-014
t
R
t
F
A–B
0V
Figure 2. Driver Propagation Delay, Rise/Fall Timing
Figure 4. Driver Enable/Disable Timing
0.7V
DD1
RE
0.5V
DD1
0.5V
DD1
0.3V
DD1
A–B
0V
0V
t
ZL
1.5V
OUTPUT LOW
t
LZ
t
PLH
t
PHL
V
OH
RxD
V
OH
+ 0.5V
t
ZH
OUTPUT HIGH
RxD
0V
t
HZ
V
OH
– 0.5V
V
OL
RxD
1.5V
t
SKEW
= |t
PLH
– t
PHL
|
1.5V
V
OH
06021-015
V
OL
Figure 3. Receiver Propagation Delay
06021-013
1.5V
Figure 5. Receiver Enable/Disable Timing
Rev. A | Page 5 of 20
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