DS3862
Octal High Speed Trapezoidal Bus Transceiver
General Description
The DS3862 is an octal high speed schottky bus transceiver
intended for use with terminated 120
impedance lines. It is
specifically designed to reduce noise in unbalanced trans-
mission systems. The open collector drivers generate pre-
cise trapezoidal waveforms with rise and fall times of 9 ns
(typical), which are relatively independent of capacitive load-
ing 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 trans-
ceivers. In addition, the receivers use a low pass filter in con-
junction 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 180
resistor
from the bus to 5V logic supply, together with a 390
resistor
from the bus to ground. The bus can be terminated at one or
both ends.
Features
n
Guaranteed A.C. specifications on noise immunity and
propagation delay over the specified temperature and
supply voltage range
n
Temperature insensitive receiver thresholds track bus
logic level and respond symmetrically to positive and
negative going pulses
n
Trapezoidal bus waveforms reduce noise coupling to
adjacent lines
n
Open collector driver output allows wire-or connection
n
Advanced low power schottky technology
n
Glitch free power up/down protection on driver and
receiver outputs
n
TTL compatible driver and control inputs, and receiver
outputs
n
Control logic is the same as the DS3896
Logic and Connection Diagram
DS008539-1
Order Number DS3862J, DS3862N or DS3862WM
See NS Package Number J20A, N20A or M20B
February 1995
DS3862
Octal
High
Speed
T
rapezoidal
Bus
T
ransceiver
1999 National Semiconductor Corporation
DS008539
www.national.com
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
6V
Control Input Voltage
5.5V
Driver Input and Receiver Output
5.5V
Receiver Input and Driver Output
5.5V
Power Dissipation
1400 mW
Storage Temperature Range
-65C to +150C
Lead Temperature (Soldering, 4 seconds)
260C
Recommended Operating
Conditions
Min
Max
Units
Supply Voltage,V
CC
4.75
5.25
V
Operating Free Air Temperature
0
70
C
Electrical Characteristics
(Notes 2, 3)
0C
T
A
70C, 4.75V
V
CC
5.25V unless otherwise specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Driver and Control 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
An = V
CC
1
mA
I
IH
Logical "1" Input Current
An = 2.4V
40
A
I
IHC
Logical "1" Input Current
CD = T/R = 2.4V
80
A
I
IL
Logical "0" Input Current
An = 0.4V
-1
-1.6
mA
I
ILC
CD & T/R Logical "0" Input Current
CD = T/R = 0.4V
-180
-400
A
V
CL
Input Diode Clamp Voltage
Iclamp = -12 mA
-0.9
-1.5
V
Driver Output/Receiver Input
V
OLB
Low Level Bus Voltage
An = T/R = 2V, Ibus = 100 mA
0.6
0.9
V
I
IHB
Logical "1" Bus Current
An = 0.8V, Bn = 4V, V
CC
= 5.25V and 0V
10
100
A
I
ILB
Logical "0" Bus Current
An = 0.8V, Bn = 0V, V
CC
= 5.25V and 0V
100
A
V
TH
Input Threshold
V
CC
= 5V
1.5
1.7
1.9
V
Receiver Output
V
OH
Logical "1" Output Voltage
Bn = 0.9V, I
oh
= - 400A
2.4
3.2
V
V
OL
Logical "0" Output Voltage
Bn = 4V, I
ol
= 16 mA
0.35
0.5
V
I
OS
Output Short Circuit Current
Bn = 0.9V
-20
-70
-100
mA
I
CC
Supply Current
V
CC
= 5.25V
90
135
mA
Note 1: "Absolute Maximum Ratings" are those beyond which the safety of the device cannot be guaranteed. They are not meant to imply that device should be op-
erated at these limits. The table of "Electrical Characteristics" provide conditions for actual device operation.
Note 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified.
Note 3: All typicals are given for V
CC
= 5V and T
A
= 25C.
Switching Characteristics
0C
T
A
70C, 4.75V
V
CC
5.25V unless otherwise specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Driver:
t
DLH
An to Bn
CD = 0.8V, T/R = 2.0V, VL = 5V
(
Figure 1)
12
20
ns
t
DHL
12
20
ns
t
DLHC
CD to Bn
An = T/R = 2.0V, VL = 5V,
(
Figure 1)
12
20
ns
t
DHLC
15
25
ns
t
DLHT
T/R to Bn
VCI = An, VC = 5V,
(
Figure 2)
20
30
ns
t
DHLT
CD = 0.8V, RC = 390
, CL = 30 pF
25
40
ns
RL1 = 91
, RL2 = 200
, VL = 5V
t
R
Driver Output Rise Time
CD = 0.8V, T/R = 2V, VL = 5V
(
Figure 1)
4
9
20
ns
t
F
Driver Output Fall Time
4
9
20
ns
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2
Switching Characteristics
(Continued)
0C
T
A
70C, 4.75V
V
CC
5.25V unless otherwise specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Receiver:
t
RLH
Bn to An
CD = 0.8V, T/R = 0.8V
(
Figure 3)
15
25
ns
t
RHL
15
25
ns
t
RLZC
CD to An
Bn = 2.0V, T/R = 0.8V, CL = 5 pF
15
25
ns
RL1 = 390
, RL2 = NC, VL = 5V
(
Figure 4)
t
RZLC
Bn = 2.0V, T/R = 0.8V, CL = 30 pF
10
20
ns
RL1 = 390
, RL2 = 1.6K, VL = 5V
(
Figure 4)
t
RHZC
Bn = 0.8V, T/R = 0.8V, VL = 0V,
5
10
ns
RL1 = 390
, RL2 = NC, CL = 5 pF
(
Figure 4)
t
RZHC
Bn = 0.8V, T/R = 0.8V, VL = 0V,
8
15
ns
RL1 = NC, RL2= 1.6K, CL = 30 pF
(
Figure 4)
t
RLZT
T/R to An
VCI = Bn, VC = 3.4V, RC = 39
20
30
ns
CD = 0.8V, VL = 5V, RL1 = 390
,
RL2 = NC, CL = 5 pF
(
Figure 2 )
t
RZLT
VCI = Bn, VC = 3.4V, RC = 39
,
30
45
ns
CD = 0.8V, VL = 5V, RL1 = 390
,
RL2 = 1.6K, CL = 30 pF
(
Figure 2 )
t
RHZT
VCI = Bn, VC = 0V, RC = 39
5
10
ns
CD = 0.8V, VL = 0V, RL1 = 390
,
RL2 = NC, CL = 5 pF
(
Figure 2 )
t
RZHT
VCI = Bn, VC = 0V, RC = 39
,
10
20
ns
CD = 0.8V, VL = 0V, RL1 = NC
RL2 = 1.6K, CL = 30 pF
(
Figure 2)
t
NR
Receiver Noise Rejection
(
Figure 5)
9
12
ns
Pulse Width
Note: NC means open
Switching Waveforms
DS008539-2
Note: t
r
= t
f
5 ns from 10% to 90%
FIGURE 1. Driver Propagation Delays
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3
Switching Waveforms
(Continued)
DS008539-3
Note: t
r
= t
f
5 ns from 10% to 90%
FIGURE 2. Propagation Delay From T/R Pin to An or Bn.
DS008539-4
Note: t
R
= t
F
10 ns from 10% to 90%
FIGURE 3. Receiver Propagation Delays
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4
Switching Waveforms
(Continued)
Typical Application
DS008539-5
Note: t
r
= t
f
5 ns from 10% to 90%
FIGURE 4. Propagation Delay From CD Pin to An
DS008539-6
Note: t
r
= t
f
= 2 ns from 10% to 90%
FIGURE 5. Receiver Noise Immunity: No Response at Output Input Waveform.
DS008539-7
www.national.com
5
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