NSC DS3662WMX, DS3662WM, DS3662N Datasheet
DS3662
Quad High Speed Trapezoidal
™
Bus Transceiver
General Description
The DS3662 is a quad high speed Schottky bus transceiver
intended for use withterminated 120Ω impedance lines. It is
specifically designed to reduce noise in unbalanced transmission systems. The open collector drivers generate precise trapezoidal waveforms with rise and fall times of 15 ns
(typical), which are relatively independent of capacitive loading conditions on the outputs. This reduces noise coupling to
the adjacent lines without any appreciable impact on the
maximum data rate obtainable with high speed bus transceivers. In addition, the receivers use a low pass filter in conjunction with a high speed comparator, to further enhance
the noise immunity. Tightly controlled threshold levels on the
receiver provide equal rejection to both negative and positive
going noise pulses on the bus.
The external termination is intended to be a 180Ω resistor
from the bus to 5V logic supply, together with a 390Ω resistor
from the bus to ground. The bus can be terminated at one or
both ends. A two input NOR gate is provided to disable all
drivers in a package simultaneously.
Features
n Pin to pin functional replacement for DS8641
n Guaranteed AC specifications on noise immunity and
propagation delay over the specified temperature and
supply voltage range
n Temperature insensitive receiver thresholds track bus
logic level
n Trapezoidal bus waveforms reduce noise coupling to
adjacent lines
n Precision receiver thresholds provide maximum noise
immunity and symmetrical response to positive and
negative going pulses
n Open collector driver output allows wire-OR connection
n High speed Schottky technology
n 15 µA typical bus termination current with normal V
CC
or
with V
CC
=
0V
n Glitch free power up/down protection on the driver
output
n TTL compatible driver and disable inputs, and receiver
outputs
Block and Connection Diagram
Trapezoidal™is a trademark of National Semiconductor Corp.
Dual-In-Line Package
DS005803-1
Top View
Order Number DS3662J, DS3662N or DS3662WM
See NS Package Number J16A, N16A or M16B
July 1992
DS3662 Quad High Speed Trapezoidal Bus Transceiver
© 1999 National Semiconductor Corporation DS005803 www.national.com
Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage 7V
Input and Output Voltage 5.5V
Storage Temperature Range −65˚C to +150˚C
Maximum Power Dissipation (Note 1) at 25˚C
Cavity Package 1509 mW
Molded Package 1476 mW
Lead Temperature (Soldering, 4 sec.) 260˚C
Recommended Operating
Conditions
Min Max Units
Supply Voltage (V
CC
) 4.75 5.25 V
Temperature Range (T
A
) 0 70 ˚C
Note 1: Derate cavity package 10.1 mW/˚C above 25˚C; derate molded
package 11.8 mW/˚C above 25˚C.
Electrical Characteristics (Notes 3, 4)
Symbol Parameter Conditions Min Typ Max Units
DRIVER AND DISABLE INPUTS
V
IH
Logical “1” Input Voltage 2.0 V
V
IL
Logical “0” Input Voltage 0.8 V
I
I
Logical “1” Input Current V
IN
=
5.5V 1 mA
I
IH
Logical “1” Input Current V
IN
=
2.4V 40 µA
I
IL
Logical “0” Input Current V
IN
=
0.4V −1 −1.6 mA
V
CL
Input Diode Clamp Voltage I
CLAMP
=
−12 mA −0.8 −1.5 V
DRIVER OUTPUT/RECEIVER INPUT
V
OLB
Low Level Bus Voltage V
DIS
=
0.8V, V
IN
=
2V, I
BUS
=
100 mA 0.6 0.9 V
I
IHB
Maximum Bus Current V
IN
=
0.8V, V
BUS
=
4V, V
CC
=
5.25V 10 100 µA
I
ILB
Maximum Bus Current V
IN
=
0.8V, V
BUS
=
4V, V
CC
=
0V 100 µA
V
IH
High Level Receiver Threshold V
IN
=
0.8V, V
OL
=
16 mA 1.90 1.70 V
V
IL
Low Level Receiver Threshold V
IN
=
0.8V, I
OH
=
−400 µA 1.70 1.50 V
RECEIVER OUTPUT
V
OH
Logical “1” Output Voltage V
IN
=
0.8V, V
BUS
=
0.5V, I
OH
=
−400 µA 2.4 3.2 V
V
OL
Logical “0” Output Voltage V
IN
=
0.8V, V
BUS
=
4V, I
OL
=
16 mA 0.35 0.5 V
I
OS
Output Short Circuit Current V
DIS
=
0.8V, V
IN
=
0.8V, V
BUS
=
0.5V, −40 −70 −100 mA
V
OS
=
0V, V
CC
=
5.25V, (Note 5)
I
CC
Supply Current V
DIS
=
0V, V
IN
=
2V 50 90 mA
Switching Characteristics (Notes 3, 4)
Symbol Parameter Conditions Min Typ Max Units
PROPAGATION DELAYS
t
PLHD
Disable to Bus “1”
Figure 1
25 35 ns
t
PHLD
Disable to Bus “0” 25 35 ns
t
PLHB
Driver Input to Bus “1”
Figure 2
20 30 ns
t
PHLB
Driver Input to Bus “0” 20 30 ns
t
PLHR
Bus to Logical “1” Receiver Output
Figure 3
25 40 ns
t
PHLR
Bus to Logical “0” Receiver Output 25 40 ns
NOISE IMMUNITY
t
rB,tfB
Rise and Fall Times (10%–90%)
Figure 2
10 15 20 ns
of the Driver Output
t
nR
Receiver Noise Rejection No Response at Receiver 20 10 ns
Pulse Width Output as per
Figure 4
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. Thetablesof“ElectricalCharacteristics”and“RecommendedOperatingConditions”provideconditionsforactualdeviceoperation.
Note 3: Unless otherwise specified min/max limits apply across the supply and temperature range listed in the table of “Recommended Operating Conditions”. All
typical values are for T
A
=
25˚C and V
CC
=
5V.
Note 4: All currents into device pins shown as positive, out of device pins as negative, all voltages referenced to ground unless otherwise noted. All values shown
as max or min on absolute value basis.
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