hi-1570 Holt Integrated Circuits, Inc., hi-1570 Datasheet - Page 2

• Manufacturer Part Number: hi-1570
• Description: 5v Monolithic Dual Variable Amplitude Transceiver
• Manufacturer: Holt Integrated Circuits, Inc.

PIN DESCRIPTIONS
FUNCTIONAL DESCRIPTION
The HI-1570 data bus transceiver contains differential volt-
age source drivers and differential receivers. They are in-
tended for applications using a MIL-STD-1553 A/B data
bus. The device produces a trapezoidal output waveform
during transmission.
TRANSMITTER
Data input to the device’s transmitter section is from the
complementary CMOS / TTL inputs TXA/B and
The transmitter accepts Manchester II bi-phase data and
converts it to differential voltages on
The transceiver outputs are either direct or transformer cou-
pled to the MIL-STD-1553 data bus. Both coupling meth-
ods produce a nominal voltage on the bus of 7.5 volts peak
to peak at V
transmitter output amplitudes at other values of
A&B between 0 - 5 Vdc. (Contact your Holt Sales Repre-
sentative about the 0 - 10 Vdc Control Voltage option).
The transmitter is automatically inhibited and placed in the
high impedance state when both TXA/B and
ther at a logic “1” or logic “0” simultaneously. A logic “1” ap-
plied to the TXINHA/B input will force the transmitter to the
high impedance state, regardless of the state of TXA/B and
TXA B.
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PIN
10
12
13
14
15
16
17
18
19
20
11
1
2
3
4
5
6
7
8
9
CONT
V
SYMBOL
VDDA/B
TXINHB
TXINHA
RXENA
RXENB
CONT
GNDA
GNDB
BUSA
BUSA
BUSB
BUSB
RXB
RXB
RXA
RXA
TXB
TXB
TXA
TXA
A&B = 5.0 Vdc. Refer to Figure 4 for
A/B
analog output
analog output
analog output
analog output
power supply
power supply
power supply
FUNCTION
digital output
digital output
digital output
digital output
analog Input
digital input
digital input
digital input
digital input
digital input
digital input
digital input
digital input
BUSA/B and
HOLT INTEGRATED CIRCUITS
TXA B
Transmit output amplitude control (0 - 5 Vdc, see Figure 4)
MIL-STD-1533 bus driver A, positive signal
MIL-STD-1553 bus driver A, negative signal
Receiver A enable. If low, forces RXA and
Ground for bus A
+5 volt power for both bus A and bus B
MIL-STD-1533 bus driver B, positive signal
MIL-STD-1553 bus driver B, negative signal
Receiver B enable. If low, forces RXB and
Ground for bus B
Receiver B output, inverted
Receiver B output, non-inverted
Transmit inhibit, bus B. If high BUSB,
Transmitter B digital data input, non-inverted
Transmitter B digital data input, inverted
Receiver A output, inverted
Receiver A output, non-inverted
Transmit inhibit, bus A. If high BUSA,
Transmitter A digital data input, non-inverted
Transmitter A digital data input, inverted
/ are ei-
BUSA B
TXA B
V
CONT
HI-1570
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2
RECEIVER
The receiver accepts bi-phase differential data from the
MIL-STD-1553 bus through the same direct or transformer
coupled interface as the transmitter. The receiver’s differ-
ential input stage drives a filter and threshold comparator
that produces CMOS/TTL data at the RXA/B and
output pins.
Each set of receiver outputs can be independently forced
to a logic "0" by setting RXENA or RXENB low.
MIL-STD-1553 BUS INTERFACE
A direct coupled interface (see Figure 2) uses a 1:2.5 ratio
isolation transformer and two 55 ohm isolation resistors
between the transformer and the bus.
In a transformer coupled interface (see Figure 3), the
transceiver is connected to a 1:1.79 isolation transformer
which in turn is connected to a 1:1.4 coupling transformer.
The transformer coupled method also requires two
coupling resistors equal to 75% of the bus characteristic
impedance (Zo) between the coupling transformer and the
bus.
DESCRIPTION
BUSA
BUSB
RXA
RXB
disabled
disabled
low
low
RXA B
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