ACT ACT4808LDI, ACT4808LDFI, ACT4808LDF, ACT4808LD, ACT4808DI Datasheet
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eroflex Circuit T
– Data Bus Modules For The Future © SCD4808 REV E 12/9/99
ACT4808 Dual Transceivers for
MACAIR A3818, A5690, A5232, A4905
& MIL-STD-1553
Features
• ACT4808 Dual Transceiver meets
MIL-STD-1553A&B, Macair A3818, A5690, A5232
and A4905 specs
• New Low Power Model –L Available
• Operates with ±12V to ±15V & +5V Power Supplies
• Voltage source output for higher bus drive power
• Plug-in or Flat Package
• Monolithic construction using linear ASICs
• Processed and Screened to MIL-STD-883 specs
ACT4808 Transceiver
TX DATA IN
TX DATA IN
TX INHIBIT
+5 V
VEE
RX DATA IN
RX DATA IN
VCC
STROBE
DRIVER
INPUT
AMP
SHAPING
V-
ACTIVE
FILTER
OUTPUT
STAGE
V+
COMP.
COMP.
Block Diagram (without Transformer), 1/2 of unit shown
TX DATA OUT
TX DATA OUT
RX DATA OUT
RX DATA OUT
CIRCUIT TECHNOLOGY
www.aeroflex.com/act1.htm
General Description:
The Aeroflex Laboratories transceiver
model ACT4808 is a new generation
Dual monolithic transceiver which
provides full compliance with Macair
and MIL-STD-1553 data bus
requirements
The model ACT4808 performs the
front-end analog function of inputting
and outputting data through a
transformer to a MIL-STD-1553 or
Macair data bus. The ACT4808 can
be considered a "Universal"
Transceiver in that it is compatible
with MIL-STD-1553A & B, Macair
A-3818, A-4905, A-5232 and A-5690.
Design of this transceiver reflects
particular attention to active filter
performance. This results in low bit
and word error rate with superior
waveform purity and minimal zero
crossover distortion. The ACT4808
series active filter design has
additional high frequency roll-off to
provide the required Macair low
harmonic distortion waveform without
increasing the pulse delay
characteristics significantly.
Efficient transmitter electrical and
thermal design provides low internal
power dissipation and heat rise at
high and well as low duty cycles.The
receiver input threshold is set
Internally.
Transmitter
The Transmitter section accepts
bi-phase TTL data at the input and
when coupled to the data bus as per
Figure 3 or 4 and by two 70 Ohm
terminations (Z
produced is 6.5 Volts minimum P-P at
A-A’. When both DATA and DATA
O), the data bus signal
echnology
Aeroflex Circuit Technology SCD4808 REV E 12/9/99 Plainview NY (516) 694-6700
inputs are held low or high, the
transmitter output becomes a high
impedance and is “removed” from
the line. In addition, an overriding
“INHIBIT" input provides for the
removal of the transmitter output
from the line. A logic “1” applied to
the “INHIBIT” takes priority over the
condition of the data inputs and
disables the transmitter. (See
Transmitter Logic Waveforms,
Figure 1.)
The transmitter utilizes an active
filter to suppress harmonics above
1MHz to meet Macair specifications
A-3818, A-4905, A-5232 and
A-5690. The transmitter may be
Figure 1 – Transmitter Logic Waveforms
DATA IN
safely operated for an indefinite
period at 100% duty cycle into a
data bus short circuit (Pt. A-A’).
Receiver
The Receiver section accepts
bi-phase differential data at the input
and produces two TTL signals at the
output. The outputs are DATA and
, and represent positive and
DATA
negative excursions of the input
beyond a pre-determined threshold.
(See Receiver Logic Waveforms,
Figure 2.)
The internal threshold is nominally
set to detect data bus signals
exceeding 1.10 Volts P-P and reject
signals less than 0.6 Volts P-P
when used with a 1:1 turns ratio
transformer. (See Figure 4 for
transformer data and typical
connection.)
A low level at the Strobe input
inhibits the DATA and DATA
outputs.
DATA IN
INHIBIT
LINE TO LINE
OUTPUT
NOTES:
1. Line to line waveforms illustrate Macair signals, MIL-STD-1553 signals are trapezoidal
2. DATA and DATA
3. DATA and DATA
inputs must be complementary waveforms or 50% duty cycle average, with no delays between them.
must be in the same state during off time (both high or low).
Figure 2 – Receiver Logic Waveforms
LINE TO LINE
INPUT
DATA OUT
DATA OUT
NOTE: Waveforms shown are for normally low devices. For normally high receiver output
level
devices, the receiver outputs are swapped as shown by the dashed lines
2
Note overlap
Aeroflex Circuit Technology SCD4808 REV E 12/9/99 Plainview NY (516) 694-6700
Absolute Maximum Ratings, Per Channel
Operating Case Temperature
Storage Case Temperature
-55°C to +125°C
-65°C to +150°C
Power Supply Voltages ±16 V +7 V
Logic Input Voltage -0.3 V to +5.5 V
Receiver Differential Input
±40 V
Receiver Input Voltage (Common Mode) ±10V
Driver Peak Output Current 150 mA
Total Package Power Dissipation over the Full Operating
Case Temperature Range
Maximum Junction to Case Temperature
3.6 Watts
18°C
Junction-Case, Thermal Resistance 5°C/W
Electrical Characteristics Per Channel, Transmitter Section
1/ 2/
Input Characteristics, TX DATA IN or TX DATA IN
Parameter Condition Symbol Min Typ Max Unit
"0" Input Current VIN = 0.4 V I
"1" Input Current V
= 2.7 V I
IN
"0" Input Voltage - V
"1" Input Voltage - V
ILD
IHD
IHD
IHD
2.0 - - V
-0.2 -0.4 mA
-
-
1.0
40 µA
- - 0.7 V
Inhibit Characteristics
"0" Input Current V
"1" Input Current V
"0" Input Voltage - V
"1" Input Voltage - V
Delay from TX inhibit(0→1) to inhibited output - t
Delay from TX inhibit, (1→0) to active output - t
Differential output noise, inhibit mode 3
Differential output impedance
* 4/ Z
= 0.4 V I
IN
= 2.7 V I
IN
/ V
* See Aeroflex Application note# 113 for reference.
Output Characteristics
Differential output - Direct coupled stub
Differential output - Transformer coupled stub
(see Fig. 3 and 4)
Differential output offset - Direct coupled stub Fig. 4
Differential output offset - Xformer coupled stub Fig. 3
Differential output rise / fall times (see Fig. 5) 10% - 90% t
Delay from 50% point of TX DATA or TX DATA
input to
zero crossing of differential output.
Pt. B - B’
= 70Ω
Z
O
5/
- t
ILI
IHI
ILI
IHI
DXOFF
DXON
NOI
OI
V
O 26
V
OS
& t
R
F
DTX
-0.2 -0.4 mA
-
- 1.0 40
µA
- - 0.7 V
2 - - V
- 300 450 nS
- 300 450 nS
- 0.8 10 mVp-p
2K - - Ω
18
29
21
-
-
-
-
32
25
±360
±250
Vp-p
Vp-p
mVpk
mVpk
200 250 300 nS
240 300 nS
3
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