Standard Products
DRS4485 Dual RS485 Interface Transceiver
Radiation Tolerant
www.aeroflex.com/RadHard
May 27, 2010
FEATURES
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Radiation Performance
- Total dose > 100 krad (Si)
Designed for RS485 and RS422 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
Serial data rate 500KHz maximum
Voltage source output
Receiver output Hi for V
IN
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
Available on DSCC SMD 5962-09226
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 DRS4485 is a monolithic dual bus/line transceiver designed for multipoint data
transmission standard RS485 applicatons. The DRS4485 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 D
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
±5V
±5V
-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 3/
Receiver output high voltage
Receiver output low voltage
Receiver input differential resistance 3/
Receiver input common-mode resistance 3/
Driver short-circuit current
Receiver short-circuit current
-6.5V
V
CM
+5V
V
CM
= 0
I
O
= -0.4mA
I
O
= 0.4mA
-
-
-
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
-
-
-
2.4
Typ
-
-
-
2.55
-
-
-
±1
-0.5
-
4.0
-
30K
8K
70
7
160
-
-
-
-
100
22
Max
5
5
0.2
3
0.2
-
0.8
±2
-0.1
400
-
0.5
-
-
140
85
Unit
Vp-p
Vp-p
Vp-p
V
V
V
V
µA
V
mV
V
V
mA
mA
V
OD
V
OC
V
OC
V
IH
V
IL
I
IN
V
TH
V
TH
V
OH
V
OL
R
IN DIFF
R
IN CM
I
OS
I
OSR
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
60
Icc1
Icc2
Icc3
I
CC2
-
21.3
40
mA
I
CC1
-
8.2
16
mA
Sym Min Typ Max Unit
X = Hi/Lo, 0V = GND, 5V = 5V
DC
, HiZ = high impedance, LoZ = low impedance, NL = No Load
I
CC3
-
43
65
mA
SCD4485 Rev D 5/27/2010
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
Receiver rise or fall time
Receiver enable delay
Receiver disable delay
I
O
= 0
See test ckt
Figure 2
R
DIFF
= 60
See test ckt
Figure 2
Condition
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
15
150
250
300
150
150
75
150
150
Unit
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
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.
3. Not tested, guaranteed by design to the specified limits.
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
X
OPEN
SHORT
RE
L
L
H/OPEN
X
X
Output
H
L
H
H
H
R
30
BUS
DI
BUSN
R
Voc
30
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 D 5/27/2010
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 D 5/27/2010
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 D 5/27/2010
Aeroflex Plainview
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