SCD4485 Rev B
FEATURES
❑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.
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.
ACT4485 Dual RS485 Interface Transceiver
Standard Products
October 8, 2008
Radiation Tolerant
BUS
BUSN
DI
DE
FIGURE 1 – SCHEMATIC
Rx O
UT
Rx E
N
Rx
D
R
V
CC
GND
Channel 1 or 2
www.aeroflex.com/RadHard
2
SCD4485 Rev B 10/8/08 Aeroflex Plainview
ABSOLUTE MAXIMUM RATINGS
Operating Case Temperature -55°C to +125°C
Storage Case Temperature -65°C to +150°C
Power Supply Voltages (VCC) +12VDC
Control Input Voltage -0.5 VDC to Vcc + 0.5VDC
Driver Input Voltage -0.5 VDC to Vcc + 0.5VDC
Driver Output Voltage ±5V
Receiver Input Voltage ±5V
Receiver Output Voltages -0.5 VDC to Vcc + 0.5VDC
ELECTRICAL CHARACTERISTICS 1/ 2/
Parameter Condition Symbol Min Typ Max Unit
Differential driver output voltage (unloaded) IO = 0 VOD1 2.5 - 5 Vp-p
Differential driver output voltage (with load)
See Figure 2
VOD2 2.5 - 5 Vp-p
Change in magnitude of driver differential
output Voltage for complementary states
ΔVOD - - 0.2 Vp-p
Driver common mode output voltage VOC -2.553 V
Change in magnitude of driver
common-mode output Voltage for
complementary states
Δ|VOC|--0.2V
Input high voltage
DE, DI, RE
VIH 2.4 - - V
Input low voltage VIL -0.8V
Input current IIN ±1 ±2 µA
Differential input threshold voltage for
receiver
-6.5V ≤VCM ≤+5V VTH -0.5 -0.1 V
Receiver input hysteresis VCM = 0 ΔVTH - 160 400 mV
Receiver output high voltage IO = 4mA VOH 4.0 - - V
Receiver output low voltage IO = -4mA VOL --0.5V
Receiver threshold - RXTHLD -500 -400 -100 mVp
Receiver input differential resistance - RINDIFF 30K - - Ω
Receiver input common-mode resistance - RINCM 8K - - Ω
Driver short-circuit current - IOS 70 100 140 mA
Receiver short-circuit current V
OH to GND or VOL to Vcc IOSR 72285mA
STATIC DC POWER SUPPLY CURRENTS
Parameter Conditions Sym Min Typ Max Unit
Supply
current See Below Table
ICC1 -8.2-mA
ICC2 - 21.3 - mA
ICC3 -43-
mA
Channel 2 (1)
Outputs
Channel 1 (2) Outputs
Note
DE DI RE DRVout Load
All disabled 0V X 0V HiZ X Icc1
5VX0V LoZ NL Icc2
5V X 0V LoZ 60ΩIcc3
X = Hi/Lo, 0V = GND, 5V = 5VDC, HiZ = high impedance, LoZ = low impedance, NL = No Load
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SCD4485 Rev B 10/8/08 Aeroflex Plainview
SWITCHING CHARACTERISTICS 1/ 2/
Parameter Condition Symbol Min Typ Max Unit
Driver input to output delay RDIFF = 60Ω
See test ckt
Figure 2
tPLH - 125 200 nS
Driver input to output delay tPHL - 80 150 nS
Driver output to output delay tSKEW -15 nS
Driver rise or fall time tr, tf- 80 150 nS
Driver Output enable delay tZH - 200 250 nS
Driver Output disable delay tLZ - 230 300 nS
Receiver input to output delay IO = 0
See test ckt
Figure 2
tPLH - 40 100 nS
tPHL - 60 100 nS
Receiver rise or fall time tr, tf-3650 nS
Receiver enable delay tZL - 100 150 nS
Receiver disable delay tZH - 50 150 nS
Notes:
1. Min/Max values are for VCC = +5V ±5%, TC = -55°C to +125°C. Typical values are measured at VCC = +5V and TC = +25°C.
2. Current measurements are for both channels.
DRIVER FUNCTION TABLE
Inputs Outputs
DI DE BUS BUSN
HH/OPENH L
LH/OPENL H
X L OFF HiZ OFF HiZ
RECEIVER FUNCTION TABLE
DIFF Input RE Output
> -100mV L H
< -500mV L L
-500mV < VID < -100mV L H
XH/OPENH
OPEN X H
SHORT X H
+
–
R
R
BUS
BUSN
DI
DE
Voc
VODIFF CDIFF
CSHLD
CSHLD
RX OUT
CL
RE
IOUT
FIGURE 2 – DRIVER/RECEIVER TIMING TEST CIRCUIT (Channel 1 or 2)
40pF
1500pF
1500pF
200pF
30Ω
30Ω
4
SCD4485 Rev B 10/8/08 Aeroflex Plainview
FIGURE 3 – DRIVER SWITCHING WAVEFORMS
FIGURE 3A – TYPICAL DRIVER OUTPUTS
DI
DI
3V
1.5V
t
PLH
t
r
t
SKEW
1/2 V
O
V
OC
80%
10%
0V
VBUSN
VBUS
V
O
–V
O
0V, VODIFF
90%
1.5V
t
PHL
t
SKEW
1/2 V
O
20%
t
f
VODIFF = VBUS – VBUSN
VBUS
VBUSN
5
SCD4485 Rev B 10/8/08 Aeroflex Plainview
FIGURE 4 – RECEIVER SWITCHING WAVEFORMS
FIGURE 4A – TYPICAL RECEIVER OUTPUTS
1.5V
t
PHL
–V
OD2
0V
1.5V
t
PLH
V
OD2
V
OL
V
OH
Rx Out
0V, VO
DIFF
VO
DIFF
6
SCD4485 Rev B 10/8/08 Aeroflex Plainview
4X R.020
ACT4485
88379
MADE IN THE USA
Pin # Function Pin # Function
1 DRIVER ENABLE 1 10 VCC
2 RECEIVER ENABLE 1 11 GROUND
3 RECEIVER OUT 1 12 BUS 2
4 NC 13 BUSN 2
5 DRIVER IN 1 14 DRIVER IN 2
6 BUSN 1 15 NC
7 BUS 1 16 RECEIVER OUT 2
8 GROUND 17 RECEIVER ENABLE 2
9 VCC 18 DRIVER ENABLE 2
PIN # vs FUNCTION TABLE
PACKAGE CONFIGURATION OUTLINE
7
PLAINVIEW, NEW YORK
Toll Free: 800-THE-1553
Fax: 516-694-6715
SE AND MID-ATLANTIC
Tel: 321-951-4164
Fax: 321-951-4254
INTERNATIONAL
Tel: 805-778-9229
Fax: 805-778-1980
WEST COAST
Tel: 949-362-2260
Fax: 949-362-2266
NORTHEAST
Tel: 603-888-3975
Fax: 603-888-4585
CENTRAL
Tel: 719-594-8017
Fax: 719-594-8468
www.aeroflex.com info-ams@aeroflex.com
Our passion for performance is defined by three
attributes represented by the se three icons :
solution-minded, performance-driven and customer-focused
Aeroflex Microelectronic Solutions reserves the right to
change at any time without notice the specifications, design,
function, or form of its products described herein. All
parameters must be validated for each customer's application
by engineering. No liability is assumed as a result of use of
this product. No patent licenses are implied.
SCD4485 Rev B 10/8/08
EXPORT CONTROL: EXPOR T WARNING:
This product is controlled for export under the International Traffic in
Arms Regulations (ITAR). A license from the U.S. Department of
State is required prior to the export of this product from the United
States.
Aeroflex’s military and space products are controlled for export under
the International Traffic in Arms Regulations (ITAR) and may not be
sold or proposed or offered for sale to certain countries. (See ITAR
126.1 for complete information.)
CONFIGURATIONS AND ORDERING INFORMATION
Model No. Specifications Case
ACT4485-S Military Temperature, -55°C to +125°C
Screened in accordance with MIL-PRF-38534, Class K Flat Pack
ACT4485-7 Commercial Flow, +25°C testing only
