Standard Products
Datasheet
DRS4485 Dual RS485 Interface Transceiver
Radiation Tolerant
www.aeroflex.com/RadHard
December 5, 2014
FEATURES
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
Monolithic construction
Designed for commercial, industrial and aerospace applications
Plainview is a Class H & K MIL-PRF-38534 manufacturer
Packaging – Hermetic Flat Package
- 18-lead, 0.63"sq x 0.125"Ht
- Weight - 3.50 grams max
Aeroflex Plainview’s Radiation Hardness Assurance Plan is DLA Certified to MIL-PRF-38534, Appendix G.
GENERAL DESCRIPTION
The Aeroflex-Plainview DRS4485 is a monolithic dual bus/line transceiver designed for multi-point data
transmission standard RS485 applications. 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.
V
CC
DI
DE
D
R
BUS
BUSN
Channel 1 or 2
Rx O
UT
Rx
Rx E
N
GND
FIGURE 1 – SCHEMATIC
SCD4485 Rev G
ABSOLUTE MAXIMUM RATINGS
Parameter
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
Range
-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
NOTICE: Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress rating
only; functional operation beyond the "Operation Conditions" is not recommended and extended exposure beyond the "Operation Conditions"
may affect device reliability.
ELECTRICAL CHARACTERISTICS
2/ 4/
Parameter
Differential driver output voltage (unloaded)
Differential driver output voltage (with load) 1/
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 1/
Differential input threshold voltage for receiver
Receiver input hysteresis 3/
Receiver output high voltage 1/
Receiver output low voltage 1/
Receiver input differential resistance 3/
Receiver input common-mode resistance 3/
Driver short-circuit current 1/
Receiver short-circuit current 1/
-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
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
Min
2.5
2.5
-
-
-
2.4
Typ
3.0
3.0
-
2.55
-
-
-
±1
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
-0.5
-
4.0
-
30K
8K
50
7
-0.2
160
-
-
-
-
80
50
STATIC DC POWER SUPPLY CURRENTS 2/
Input
Conditions
DE
0V
5V
5V
DI
X
X
X
RE
5V
0V
0V
Driver Output
Conditions
Output Output
State
Load
HiZ
LoZ
LoZ
X
NL
60 W
I
CC1
1/
I
CC2
1/
I
CC3
-
-
-
10
29
50
16
40
65
mA
mA
mA
Channel Conditions
Sym
Min
Typ
Max
Unit
Channel 1
Driver
Receiver
Channel 2
Driver
Receiver
Disabled Disabled Disabled Disabled
Enabled
Enabled
Enabled Disabled Disabled
Enabled Disabled Disabled
DE=Driver En, DI=Driver In, RE=Receiver En
X=HiLo. 0V=GND. 5V=V
DC
. HiZ=high impedance. LoZ=low impedance. L=No Load
SCD4485 Rev G 12/5/14
2
Aeroflex Plainview
SWITCHING CHARACTERISTICS
4/
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
C
L
= 15pF
R
DIFF
= 60W
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
4
100
160
220
80
90
26
90
120
Max
200
150
15
150
250
350
150
150
50
150
150
Unit
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
nS
Notes:
1/ The active element that makes up the device has been tested to 200krad(Si) to assure RHA designator level "R"
(100krad(Si)) of method 1019, Condition A of MIL-STD-883 at +25°C for these parameters. The element will be retested after
design or process changes that can affect RHA response of this element. Post Radiation test limits for the input current (I
IN
)
test, is Max = ±3uA.
2/ Current measurements are for both channels.
3/ Not tested, guaranteed by design to the specified limits.
4/ 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.
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
BUS
DI
BUSN
R
30
VO
DIFF
C
SHLD
1500pF
+
–
C
DIFF
200pF
RX OUT
I
OUT
R
Voc
30
C
SHLD
1500pF
DE
RE
C
L
15pF
FIGURE 2 – DRIVER/RECEIVER TIMING TEST CIRCUIT (Channel 1 or 2)
SCD4485 Rev G 12/5/14
3
Aeroflex Plainview
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 G 12/5/14
4
Aeroflex Plainview
FIGURE 3B – DRS4485 DRIVING 500FT OF BELDEN 3105A, 120Ω CABLE
SCD4485 Rev G 12/5/14
5
Aeroflex Plainview
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