5
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)668-7017 • www.exar.com SP490,491_101_062711
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device
at these ratings or any other above those indicated in the operation
sections of the specications below is not implied. Exposure to
absolute maximum rating conditions for extended periods of time
may affect reliability.
V
CC
...................................................................................................+7V
Input Voltages
Logic.................................................-0.5V to (V
CC
+0.5V)
Drivers..............................................-0.5V to (V
CC
+0.5V)
Receivers................................................................±14V
Output Voltages
Logic................................................-0.5V to (V
CC
+0.5V)
Drivers....................................................................±14V
Receivers.........................................-0.5V to (V
CC
+0.5V)
Storage Temperature.....................................................-65˚C to +150
Power Dissipation.................................................................1000mW
T
MIN
to T
MAX
and V
CC
= 5V ± 5% unless otherwise noted.
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
SP491 DRIVER
DC Characteristics
Differential Output Voltage GND V
CC
Volts Unloaded; R = ∞ ; see gure 1
Differential Output Voltage 2 V
CC
Volts With Load; R = 50Ω; (RS422);
see gure 1
Differential Output Voltage 1.5 V
CC
Volts With Load; R = 27Ω; (RS485); see
gure 1
Change in Magnitude of Driver
Differential Output Voltage for
Complimentary States 0.2 Volts R = 27Ω or R = 50Ω; see gure 1
Driver Common-Mode
Output Voltage 3 Volts R = 27Ω or R = 50Ω; see gure 1
Input High Voltage 2.0 Volts Applies to D, REB, DE
Input Low Voltage 0.8 Volts Applies to D, REB, DE
Input Current ±10 µA Applies to D, REB, DE
Driver Short-Circuit Current
V
OUT
= HIGH 250 mA -7V ≤ V
O
≤ 12V
V
OUT
= LOW 250 mA -7V ≤ V
O
≤ 12V
SP491 DRIVER
AC Characteristics
Maximum Data Rate 5 Mbps REB = 5V, DE = 5V
Driver Input to Output 30 60 ns t
PLH
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see gures 3 and 6
Driver Input to Output 30 60 ns t
PHL
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see gures 3 and 6
Driver Skew 5 10 ns see gures 3 and 6,
t
SKEW
= | t
DPLH
- t
DPHL
|
Driver Rise or Fall Time 15 40 ns From 10% to 90%; R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF; see gures 3 and 6
Driver Enable to Output High 40 70 ns C
L1
= C
L2
= 100pF; see gures
4 and 7; S
2
closed
Driver Enable to Output Low 40 70 ns C
L1
= C
L2
= 100pF; see gures
4 and 7; S
1
closed
Driver Disable Time from Low 40 70 ns C
L1
= C
L2
= 100pF; see gures
4 and 7; S
1
closed
Driver Disable Time from High 40 70 ns C
L1
= C
L2
= 100pF; see gures
4 and 7; S
2
closed
ELECTRICAL CHARACTERISTICS
