DS1487N NSC [National Semiconductor], DS1487N Datasheet - Page 3

• Manufacturer Part Number: DS1487N
• Description: Low Power RS-485 1⁄4 Unit Load Multipoint Transceiver
• Manufacturer: NSC [National Semiconductor]

Symbol
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
t
f
PLHD
PHLD
SKEW
r
f
ZH
ZL
LZ
HZ
PLHD
PHLD
SKEW
ZH
ZL
LZ
HZ
max
Switching Characteristics
Note 2: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices
should be operated at these limits. The table of “Electrical Characteristics” specifies conditions of device operation.
Note 3: Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground except V
V
Note 4: All typicals are given for: V
Note 5:
Note 6: I
Note 7: Supply current specification is valid for loaded transmitters when DE = 0V or enabled (DE = H) with no load.
Note 8: f = 1 MHz, t
Note 9: C
Note 10: f
rate unit interval (1/f
Over Supply Voltage and Operating Temperature Ranges, unless otherwise specified (Notes 4, 8, 9)
Parameter Measurement Information
ID
.
IN2
|V
L
max
OD
includes jig and probe capacitance.
Driver Differential Propagation Delay — Low to High
Driver Differential Propagation Delay — High to Low
Differential Skew |t
Driver Rise Time
Driver Fall Time
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable from Output Low
Driver Disable from Output High
Receiver Differential Propagation Delay — Low to High
Receiver Differential Propagation Delay — High to Low
Differential Skew |t
Receiver Enable to Output High
Receiver Enable to Output Low
Receiver Disable from Output Low
Receiver Disable from Output High
Maximum Data Rate
includes the receiver input current and driver TRI-STATE leakage current.
is the guaranteed data rate for 50 ft of twisted pair cable. f
| and |V
max
r
and t
). Using a 10% ratio yields f
OC
| are changes in magnitude of V
f
FIGURE 2. V
FIGURE 1. V
6 ns, Z
CC
PHLD
PHLD
O
= +5.0V, T
= 50 .
Parameter
− t
− t
OD3
OD
PLHD
PLHD
A
DS012920-2
max
= +25˚C.
|
|
= (0.1)/50 ns = 2.0 Mb/s. Higher data rates may be supported by allowing larger ratios.
OD
and V
DS012920-3
OC
max
respectively, that occur when the input changes state.
may be conservatively determined from the ratio of driver transition time (t
3
R
C
C
C
C
C
C
(Note 10)
L
L
L
L
L
L
L
= 54 , C
= 100 pF
= 100 pF
= 15 pF
= 15 pF
= 15 pF (RO)
= 15 pF
Conditions
L
= 100 pF
FIGURE 3.
Min
2.0
10
10
30
30
0
3
3
0
Typ
190
210
40
39
25
25
50
65
80
80
20
45
40
50
55
1
Max
200
200
200
200
400
400
150
150
150
150
80
80
10
50
50
50
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r
) to the data
OD1/2/3
DS012920-4
Units
Mbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
and