Standard Products
ACT4485 Dual RS485 Interface Transceiver
Radiation Tolerant
www.aeroflex.com/RadHard
October 8, 2008
FEATURES
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Radiation Performance
- Total dose > 100 krad (Si)
Designed for RS485 Interface Applications
Single +5V supply
+5V to -7V Bus common mode range source output
Driver maintains high impedance in three-state or with the power off
Combined Impedance of a driver output and receiver allows up to 32 transceivers on the bus
200 mV typical input hysteresis
Voltage source output
Receiver output Hi for Vin Diff = 0V
< 5ns skew between BUS and BUSN complementary outputs
0.63"sq. x 0.125"ht, 18 lead, hermetic flat package
Monolithic construction
Designed for commercial, industrial and aerospace applications
Plainview is a Class H & K MIL-PRF-38534 manufacturer
Note: Aeroflex Plainview does not currently have a DSCC certified Radiation Hardened Assurance
Program.
V
CC
DI
D
R
BUS
BUSN
DE
Channel 1 or 2
Rx O
UT
Rx
Rx E
N
GND
FIGURE 1 – SCHEMATIC
GENERAL DESCRIPTION
The Aeroflex-Plainview ACT4485 is a monolithic dual bus/line transceiver designed for multipoint data
transmission standard RS485 applicatons. The ACT4485 meets TIA/EIA -485 requirements. The receiver has a
fail-safe feature which guarantees a high output state when the BUS is open or shorted.
SCD4485 Rev B
ABSOLUTE MAXIMUM RATINGS
Operating Case Temperature
Storage Case Temperature
Power Supply Voltages (V
CC
)
Control Input Voltage
Driver Input Voltage
Driver Output Voltage
Receiver Input Voltage
Receiver Output Voltages
-55°C to +125°C
-65°C to +150°C
+12V
DC
-0.5 V
DC
to Vcc + 0.5V
DC
-0.5 V
DC
to Vcc + 0.5V
DC
±5
V
±5
V
-0.5 V
DC
to Vcc + 0.5V
DC
ELECTRICAL CHARACTERISTICS
1/ 2/
Parameter
Differential driver output voltage (unloaded)
Differential driver output voltage (with load)
Change in magnitude of driver differential
output Voltage for complementary states
Driver common mode output voltage
Change in magnitude of driver
common-mode output Voltage for
complementary states
Input high voltage
Input low voltage
Input current
Differential input threshold voltage for
receiver
Receiver input hysteresis
Receiver output high voltage
Receiver output low voltage
Receiver threshold
Receiver input differential resistance
Receiver input common-mode resistance
Driver short-circuit current
Receiver short-circuit current
-6.5V
≤
V
CM
≤
+5V
V
CM
= 0
I
O
= 4mA
I
O
= -4mA
-
-
-
-
V
OH
to GND or V
OL
to Vcc
DE, DI, RE
See Figure 2
Condition
I
O
= 0
Symbol
V
OD1
V
OD2
Min
2.5
2.5
-
-
-
Typ
-
-
-
2.55
-
Max
5
5
0.2
3
0.2
Unit
Vp-p
Vp-p
Vp-p
V
V
Δ
V
OD
V
OC
Δ|
V
OC
|
V
IH
V
IL
I
IN
V
TH
2.4
-
-
±1
-
0.8
±2
-0.1
V
V
µA
V
mV
V
V
mVp
Ω
Ω
mA
mA
-0.5
-
4.0
-
-500
30K
8K
70
7
160
-
-
-400
-
-
100
22
Δ
V
TH
V
OH
V
OL
R
X
THLD
R
IN DIFF
R
IN CM
I
OS
I
OSR
400
-
0.5
-100
-
-
140
85
STATIC DC POWER SUPPLY CURRENTS
Parameter
Supply
current
Channel 2 (1)
Outputs
All disabled
Conditions
See Below Table
Channel 1 (2) Outputs
Note
DE
0V
5V
5V
DI
X
X
X
RE
0V
0V
0V
DRVout
HiZ
LoZ
LoZ
Load
X
NL
60Ω
Icc1
Icc2
Icc3
I
CC1
I
CC2
-
-
8.2
21.3
-
-
mA
mA
Sym Min Typ Max Unit
I
CC3
-
43
-
mA
X = Hi/Lo, 0V = GND, 5V = 5V
DC
, HiZ = high impedance, LoZ = low impedance, NL = No Load
SCD4485 Rev B 10/8/08
Aeroflex Plainview
2
SWITCHING CHARACTERISTICS
1/ 2/
Parameter
Driver input to output delay
Driver input to output delay
Driver output to output delay
Driver rise or fall time
Driver Output enable delay
Driver Output disable delay
Receiver input to output delay
I
O
= 0
See test ckt
Figure 2
Condition
R
DIFF
= 60
Ω
See test ckt
Figure 2
Symbol
t
PLH
t
PHL
t
SKEW
t
r,
t
f
t
ZH
t
LZ
t
PLH
t
PHL
t
r,
t
f
t
ZL
t
ZH
Min
-
-
-
-
-
-
-
-
-
-
-
Typ
125
80
1
80
200
230
40
60
36
100
50
Max
200
150
5
150
250
300
100
100
50
150
150
Unit
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
Receiver rise or fall time
Receiver enable delay
Receiver disable delay
Notes:
1. Min/Max values are for V
CC
= +5V ±5%, T
C
= -55°C to +125°C. Typical values are measured at V
CC
= +5V and T
C
= +25°C.
2. Current measurements are for both channels.
DRIVER FUNCTION TABLE
Inputs
DI
H
L
X
DE
H/OPEN
H/OPEN
L
BUS
H
L
OFF HiZ
Outputs
BUS
N
L
H
OFF HiZ
RECEIVER FUNCTION TABLE
DIFF Input
> -100mV
< -500mV
-500mV < V
ID
< -100mV
X
OPEN
SHORT
RE
L
L
L
H/OPEN
X
X
Output
H
L
H
H
H
H
R
30
Ω
BUS
DI
BUSN
R
Voc
30
Ω
VO
DIFF
C
SHLD
1500pF
+
–
C
DIFF
200pF
RX OUT
I
OUT
C
L
40pF
C
SHLD
1500pF
DE
RE
FIGURE 2 – DRIVER/RECEIVER TIMING TEST CIRCUIT (Channel 1 or 2)
SCD4485 Rev B 10/8/08
Aeroflex Plainview
3
DI
3V
DI
0V
t
PLH
V
BUS
t
PHL
1/2 V
O
V
BUSN
V
OC
V
BUS
1/2 V
O
t
SKEW
VO
DIFF
= V
BUS
– V
BUSN
V
O
0V, VO
DIFF
–V
O
10%
t
r
t
f
80%
90%
20%
1.5V
1.5V
V
BUSN
t
SKEW
FIGURE 3 – DRIVER SWITCHING WAVEFORMS
FIGURE 3A – TYPICAL DRIVER OUTPUTS
SCD4485 Rev B 10/8/08
Aeroflex Plainview
4
V
OH
Rx Out
V
OL
t
PHL
V
OD2
1.5V
1.5V
t
PLH
VO
DIFF
0V
0V, VO
DIFF
–V
OD2
FIGURE 4 – RECEIVER SWITCHING WAVEFORMS
FIGURE 4A – TYPICAL RECEIVER OUTPUTS
SCD4485 Rev B 10/8/08
Aeroflex Plainview
5
Embedded System
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