HI-8787, HI-8788
September 2006
ARINC INTERFACE DEVICES
16 bit parallel data converted to 429 & 561 serial data out
PIN CONFIGURATION
DESCRIPTION
The HI-8787 and HI-8788 are system components for
interfacing 16 bit parallel data to an ARINC 429 bus. They
combine logic and line driver on one chip. The HI-8787 has
an output resistance of 37.5 ohms, and the HI-8788 has
output resistance of 10 ohms to facilitate external lightning
protection circuitry. The technology is analog/digital
CMOS.
Both products offer high speed data bus transactions into a
buffer register. After loading 2 each 16-bit words, data is
automatically transferred and transmitted. The data rate is
equal to the clock rate. Parity can be enabled in the 32nd
bit. Reset is used to initialize the logic upon startup. Word
gaps are sent automatically.
The part requires +/- 10 volt supplies in addition to a 5 volt
supply.
28 - 561 SYNC
D4 - 1
N/C - 2
D5 - 3
D6 - 4
D7 - 5
D8 - 6
D9 - 7
D10 - 8
25 - 561 DATA
27 - VCC
32 - D3
31 - D2
30 - D1
29 - D0
26 - V+
24 - TXBOUT
HI-8787PQI
HI-8787PQT
HI-8788PQI
&
HI-8788PQT
23 - TXAOUT
22 - V-
21 - PARITY ENB
20 - XMT RDY
19 - XMIT CLK
18 - RESET
17 - WRITE
D12 - 10
D13 - 13
A0 - 12
D14 - 14
D15 - 15
FEATURES
32-Pin Plastic PQFP package
l
l
l
l
l
Automatically converts 16 bit parallel data
to ARINC 429 or 561 serial data
High speed data bus interface
On-chip line driver
Available in small TQFP package
Military processing options
(DS8787 Rev.H)
HOLT INTEGRATED CIRCUITS
www.holtic.com
SLP1.5 - 16
GND - 11
D11 - 9
09/06
HI-8787, HI-8788
PIN DESCRIPTIONS
PIN
28
1, 3-10,13-15, 29-32
11
12
16
17
18
19
20
21
22
23
24
25
26
27
SYMBOL
561 SYNC
Dn
GND
A0
SLP1.5
WRITE
RESET
XMIT CLK
XMT RDY
PARITY ENB
V-
TXAOUT
TXBOUT
561 DATA
V+
VCC
FUNCTION
digital output
digital inputs
power supply
digital input
digital input
digital input
digital input
digital input
digital output
digital input
power supply
analog output
analog output
digital output
power supply
power supply
DESCRIPTION
ARINC 561 Sync signal
Parallel 16 bit bus input
Ground
Load address, A0=1 for 1st data load, A0=0 for 2nd data load
Selects the slope of the line driver. High=1.5us
Write strobe. Loads data on rising edge.
Registers and sequencing logic initialized when low
Clock input for the transmitter
Goes high if the buffer register is empty
When high the 32nd bit output is odd parity
-10 volt rail
Line driver output - A side
Line driver output - B side
Serial output for ARINC 561 data
+10 volt rail
+5 volt rail, “one” level out of line driver, inverted for “zero”
FUNCTIONAL DESCRIPTION
The HI-8787 is a parallel to serial converter, which when
loaded with two 16 bit parallel words, outputs the data as a
32 bit serial word. Timing circuitry inserts a 4 bit gap at the
end of each 32 bit word. An input buffer register allows load
operations to take place while the previously loaded word
is being transmitted.
If the PARITY ENB pin is high, the 32nd bit will be a parity
bit, inserted so as to make the 32 bit word have odd parity. If
the PARITY ENB pin is low, the 32nd bit will be the D15 bit
of the 2nd word loaded.
Outputs are provided for both ARINC 429 (TXAOUT and
TXBOUT pins) and ARINC 561 (561 DATA and 561 SYNC
pins) type data.
A low signal applied to the RESET pin resets the HI-8787’s
internal logic so that spurious transmission does not take
place during power-up. The registers are cleared so that a
continuous gap will be transmitted until the first word is
loaded into the transmitter.
The XMIT CLK frequency is the same as the data rate.
Input data can be loaded when the XMT RDY signal is
high, which indicates the input buffer register is empty. The
first 16 bit word is loaded with the A0 input high. The sec-
ond word is loaded with A0 in the low state. Once A0 is set
low, it must not go high until after the second byte is loaded.
Each data word is loaded into the input buffer register by a
low pulse on the WRITE input. After the second word has
been loaded, the XMT RDY output goes low.
The contents of the input buffer register are transferred to
the output register during the fourth bit period of the gap. If
the fourth gap bit period of the previous word has already
been transmitted, the contents of the input buffer register
will be transferred to the output shift register during the first
bit period after the second data load, and the XMT RDY out-
put goes high.
After the output shift register is loaded, the data is shifted
out to the output logic in the order shown in figure 2.
The 561 SYNC output pulses low when the XMIT CLK is
low during the 8th bit of the ARINC transmission.
HOLT INTEGRATED CIRCUITS
2
HI-8787, HI-8788
XMIT CLK
XMT RDY
WRITE
status &
control
logic
SLP1.5
TXAOUT
A0
line
driver
word gap
counter
TXBOUT
DATA
BUS
16 to 32 bit
mux
16
32
32 bit
buffer
register
32
32 bit
shift
register
bit
counter
561 SYNC
561 DATA
output
logic
PARITY ENB
Figure 1. Block Diagram
FUNCTIONAL DESCRIPTION (Cont.)
The HI-8787 and HI-8788 have an on-chip line driver de-
signed to directly drive the ARINC 429 bus. The two ARINC
outputs (TXAOUT and TXBOUT) provide a differential volt-
age to produce a +10 volt One, a -10 volt Zero, and a 0 volt
Null. The slope of the ARINC outputs is controlled by the
SLP1.5 pin. If SLP1.5 is high, the output rise and fall time is
nominally 1.5µs. If SLP1.5 is set low, the rise and fall times
are 10µs.
The HI-8787 has 37.5 ohms in series with each line driver
output. The HI-8788 has 10.0 ohms in series. The HI-8788 is
for applications where external series resistance is needed,
typically for lightning protection devices.
A0
1
0
Load
Word 1
Word 2
Data Bus
D0 - D15
D0 - D15
ARINC Bits
ARINC 1 - ARINC 16
ARINC 17 - ARINC 32
Figure 2. Order of transmitted data
POWER SUPPLY SEQUENCING
The power supplies must be controlled to prevent large
currents during supply turn-on and turn-off. The required
sequence is V+ followed by VDD, always ensuring that V+ is
the most positive supply. The V- supply is not critical and
can be asserted at any time.
TRANSMITTER OPERATION
DATA BUS
WORD 1 VALID
WORD 2 VALID
t
SET
WRITE
t
HLD
t
WPW
A0
t
WPD
t
ASW
t
ASW
XMT RDY
t
AH
t
XD
HOLT INTEGRATED CIRCUITS
3
HI-8787, HI-8788
DATA TRANSMISSION - EXAMPLE PATTERN
GAP
32
33
34
35
36
1
2
3
4
31
32
33
GAP
34
35
36
1
2
XMIT CLK
WRITE
XMT RDY
ARINC 429 DATA
(TXAOUT-TXBOUT)
561 DATA
561 SYNC
561 SYNC
LINE DRIVER OUTPUTS
XMT CLK
t phlx
t plhx
t plhx
t phlx
t rx
90%
10%
90%
10%
t rx
DIFFERENTIAL VOLTAGE
TXAOUT - TXBOUT
10%
10V
0V
-10V
t fx
t fx
HOLT INTEGRATED CIRCUITS
4
HI-8787, HI-8788
ABSOLUTE MAXIMUM RATINGS
Voltages referenced to Ground
Supply voltages
V+.................................................12.5V
V-.................................................-12.5V
VCC.................................................. 7V
DC current per input pin................ +10ma
Power dissipation at 25°
plastic DIL............1.0W, derate 10mW/°C
ceramic DIL..........0.5W, derate 7mW/°C
Solder Temperature ........275°C for 10 sec
Storage Temperature........-65°C to +150°C
RECOMMENDED OPERATING CONDITIONS
Supply Voltages
V+.......................................+10V... ±5%
V-........................................ -10V... ±5%
VCC....................................... 5V... ±5%
Temperature Range
Industrial Screening.........-40°C to +85°C
Hi-Temp Screening........-55°C to +125°C
Military Screening..........-55°C to +125°C
NOTE:
Stresses above absolute maximum
ratings or outside recommended operating
conditions may cause permanent damage to the
device. These are stress ratings only. Operation
at the limits is not recommended.
DC ELECTRICAL CHARACTERISTICS
VCC = 5.0V, V
SS
= 0V, V+ = 10V, V- = -10V, T
A
= Operating Temperature Range (unless otherwise specified).
PARAMETER
Operating Voltage
Operating Voltage
Operating Voltage
Min. Input Voltage
Max. Input Voltage
Min. Input Current
Max. Input Current
Min. Output Voltage
Max. Output Voltage
(HI)
(LO)
(HI)
(LO)
(HI)
(LO)
SYMBOL
V
CC
V+
V-
V
IH
V
IL
I
IH
I
IL
V
OH
V
IH
CONDITION
MIN
4.75
9.5
-9.5
2.0
TYP
5
10
-10
1.4
1.4
MAX
5.25
10.5
10.5
UNITS
V
V
V
V
0.7
280
V
µA
µA
V
V
IH
= 4.9V
V
IL
= 0.1V
I
OUT
= -1.6mA
I
OUT
= 1.6mA
-1
2.7
0.4
V
Line Driver Output Levels (Ref. To GND)
ONE
NULL
ZERO
Line Driver Output Levels
(Differential TXAOUT - TXBOUT)
ONE
NULL
ZERO
Minimum Short Circuit Sink or Source Current
Operating Current Drain
Operating Current Drain (V+)
Operating Current Drain (V-)
Input Capacitance
I
OUT
I
CC
I
DD
I
EE
C
IN
no load, VCC = 5.0V
“
“
momentary magnitude
f = 100khz
f = 100khz
f = 100khz
Not tested
-20
9.0
-0.5
-11.0
80
0.8
6
-6
20
2.8
20
10.0
0
-10.0
11.0
0.5
-9.0
V
V
V
mA
mA
mA
mA
pF
no load, VCC = 5.0V
“
4.5
-0.25
-5.5
5.0
0
-5.0
5.5
0.25
-4.5
V
V
V
HOLT INTEGRATED CIRCUITS
5
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