ST485ERB
±15 kV ESD protected, low-power RS-485/RS-422 transceiver
Datasheet - production data
Description
The ST485ERB is a low-power transceiver for
RS-485 and RS-422 communication. Each driver
output and receiver input is protected against
±15 kV electrostatic discharge (HBM) ± 8 kV
(IEC-1000-4-2 contact discharge) shocks, without
latch-up. These parts contain one driver and one
receiver.
This transceiver draws 300 µA (typ.) of supply
current when unloaded or fully loaded with
disabled drivers.
Features
Low quiescent current: 300 µA
Designed for RS-485 interface applications
- 7 V to 12 V common mode input voltage
range
Driver maintains high impedance in 3-state
or with the power OFF
70 mV typical input hysteresis
30 ns propagation delay, 5 ns skew
Operates from a single 5 V supply
Current limiting and thermal shutdown for
driver overload protection
ESD protection:
± 15 kV (HBM)
± 8 kV (IEC-1000-4-2 contact
discharge)
Allows up to 64 transceivers on the bus
October 2016
It operates from a single 5 V supply.
The driver is a short-circuit current which is
limited and protected against excessive power
dissipation by thermal shutdown circuitry that
places the driver outputs into a high-impedance
state.
The ST485ERB is designed for bi-directional data
communication on multipoint bus transmission
lines (half-duplex applications).
DocID9275 Rev 8
This is information on a product in full production.
1/19
www.st.com
Contents
ST485ERB
Contents
1
Pin settings ...................................................................................... 3
2
Truth tables ...................................................................................... 4
3
4
Maximum ratings ............................................................................. 5
Electrical characteristics ................................................................ 6
5
Test circuit and typical characteristics .......................................... 9
6
Package information ..................................................................... 14
6.1
SO8 package information ................................................................ 15
6.2
SO8 tape and reel information ........................................................ 16
7
Ordering information..................................................................... 17
8
Revision history ............................................................................ 18
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ST485ERB
1
Pin settings
Pin settings
Figure 1: Pin configuration
RO 1
8
R
VCC
RE 2
7 B
DE 3
6 A
DI
4
5 GND
D
Table 1: Pin description
Pin number
Symbol
Name and function
1
RO
Receiver output
2
RE
Receiver output enable
3
DE
Driver output enable
4
DI
Driver input
5
GND
6
A
Non-inverting receiver input and non-inverting driver output
7
B
Inverting receiver input and inverting driver output
8
VCC
Ground
Supply voltage
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Truth tables
2
ST485ERB
Truth tables
Table 2: Truth table (driver)
Inputs
RE
Outputs
DE
DI
B
A
H
L
H
L
H
L
X
Z
Z
H
X
L
Note: X = “don’t care”; Z = high impedance
Table 3: Truth table (receiver)
Inputs
RE
DE
L
L
Outputs
A-B
RO
≥ 0.2 V
H
≤ -0.2 V
L
Inputs open
H
X
Z
H
Note: X = “don’t care”; Z = high impedance
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ST485ERB
3
Maximum ratings
Maximum ratings
Absolute maximum ratings are those values beyond which damage to the device may
occur. Functional operation under these condition is not implied.
Table 4: Absolute maximum ratings
Symbol
VCC
Parameter
Supply voltage
Value
Unit
7
VI
Control input voltage ( RE , DE)
-0.5 to (VCC + 0.5)
VDI
Driver input voltage (DI)
-0.5 to (VCC + 0.5)
VDO
Driver output voltage (A, B)
± 14
VRI
Receiver input voltage (A, B)
± 14
VRO
Receiver output voltage (RO)
-0.5 to (VCC + 0.5)
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Electrical characteristics
4
ST485ERB
Electrical characteristics
Table 5: ESD performance: transmitter outputs, receiver inputs
Symbol
ESD
Parameter
ESD protection voltage
Test conditions
Min.
Human body model
±15
IEC-1000-4-2
±8
Typ.
Max.
Unit
—
—
kV
In the EC tables below, VCC = 5 V ± 5 %, TA = TMIN to TMAX, unless otherwise specified.
Typical values are referred to T A = 25 °C.
Table 6: DC electrical characteristics
Symbol
VOD1
VOD2
ΔVOD
VOC
ΔVOC
6/19
Parameter
Test conditions (1)
Min.
Typ.
Differential driver output (no load)
Differential driver output (with load)
Max.
Unit
5
RL = 27 Ω (RS-485),
see Figure 2
1.5
5
RL = 50 Ω (RS-422),
see Figure 2
1.5
5
Change in magnitude of driver
differential output voltage for
complementary output states
RL = 27 Ω or 50 Ω,
see Figure 2
0.2
Driver common-mode output
voltage
RL = 27 Ω or 50 Ω,
see Figure 2
3
Change in magnitude of driver
common-mode output voltage for
complementary output states
RL = 27 Ω or 50 Ω,
see Figure 2
0.2
V
VIH
Input high voltage
RE , DE, DI
VIL
Input low voltage
RE , DE, DI
0.8
IIN1
Input current
RE , DE, DI
±2
IIN2
Input current (A, B), VCM = 0 V or
5.25 V, VDE = 0 V
VTH
Receiver differential threshold
voltage
VCM = -7 to 12 V
ΔVTH
Receiver input hysteresis
VCM = 0 V
VOH
Receiver output high voltage
IO = -4 mA,
VID = 200 mV
VOL
Receiver output low voltage
IO = 4 mA,
VID = -200 mV
0.4
IOZR
3-state (high impedance) output
current at receiver
VO = 0.4 to 2.4 V
±1
RIN
Receiver input resistance
VCM = -7 to 12 V
ICC
No load supply current,
VRE = 0 V or VCC (2)
VDE = VCC
400
900
VDE = 0 V
300
500
2.0
VIN = 12 V
1
VIN = -7 V
-0.8
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-0.2
0.2
70
µA
mA
V
mV
3.5
V
µA
kΩ
24
µA
ST485ERB
Electrical characteristics
Symbol
Parameter
Test conditions
(1)
Min.
Typ.
Max.
IOSD1
Driver short-circuit current,
VO = high
VO = -7 to 12 V (3)
35
250
IOSD2
Driver short-circuit current,
VO = low
VO = -7 to 12 V (3)
35
250
IOSR
Receiver short-circuit current
VO = 0 V to VCC
7
95
Unit
mA
Notes:
(1)All
currents into device pins are positive; all currents out of device pins are negative; all voltages are referenced
to device ground unless specified.
(2)Supply
(3)Applies
current specification is valid for loaded transmitters when V DE = 0 V
to peak current
Table 7: Driver switching characteristics
Symbol
Parameter
Test conditions (1)
Min.
Typ.
Max.
10
30
60
5
10
15
40
Propagation delay
input to output
RDIFF = 54 Ω, CL1 = CL2 = 100 pF,
see Figure 4 and Figure 6
tSK
Output skew to
output
RDIFF = 54 Ω, CL1 = CL2 = 100 pF,
see Figure 4 and Figure 6
tTLH, tTHL
Rise or fall time
RDIFF = 54 Ω, CL1 = CL2 = 100 pF,
see Figure 4 and Figure 6
tPZH
Output enable time
CL = 100 pF, S2 = closed,
see Figure 5 and Figure 7
70
90
tPZL
Output enable time
CL = 100 pF, S1 = closed,
see Figure 5 and Figure 7
70
90
tPLZ
Output disable time
CL = 15 pF, S1 = closed,
see Figure 5 and Figure 7
70
90
tPHZ
Output disable time
CL = 15 pF, S2 = closed,
see Figure 5 and Figure 7
70
90
CAB
Output AB
capacitance
tPLH, tPHL
3
43
Unit
ns
pF
Notes:
(1)All
currents into device pins are positive; all currents out of device pins are negative; all voltages are referenced
to device ground unless specified.
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Electrical characteristics
ST485ERB
Table 8: Receiver switching characteristics
Symbol
Parameter
Test conditions (1)
Min.
Typ.
Max.
20
130
210
tPLH, tPHL
Propagation delay
input to output
RDIFF = 54 Ω,CL1 = CL2 = 100 pF,
see Figure 4 and Figure 8
tSKD
Differential receiver
skew
RDIFF = 54 Ω, CL1 = CL2 = 100 pF,
see Figure 4 and Figure 8
13
tPZH
Output enable time
CRL = 15 pF, S1 = closed,
see Figure 2 and Figure 9
20
50
tPZL
Output enable time
CRL = 15 pF, S2 = closed,
see Figure 2 and Figure 9
20
50
tPLZ
Output disable time
CRL = 15 pF, S1 = closed,
see Figure 2 and Figure 9
20
50
tPHZ
Output disable time
CRL = 15 pF, S2 = closed,
see Figure 2 and Figure 9
20
50
fMAX
Maximum data rate
Unit
ns
2.5
Mbps
Notes:
(1)All
currents into device pins are positive; all currents out of device pins are negative; all voltages are referenced
to device ground unless specified
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ST485ERB
5
Test circuit and typical characteristics
Test circuit and typical characteristics
Figure 3: Receiver timing test load
Figure 2: Driver DC test load
Y
R
R = 1 kΩ
Output under test
CRL = 15 pF
VOD
R
S1
+
VCC
R = 1 kΩ
S2
VOC
Z
Figure 4: Drive/receiver timing test circuit
Figure 5: Driver timing test load
3V
DE
Y VID
CL1
R = 500 Ω
Y
DI
RO
Output under test
CL
Z RDIFF
CL2
Z
+
VCC
S1
RE
S2
DocID9275 Rev 8
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Test circuit and typical characteristics
ST485ERB
Figure 6: Driver propagation delay
Figure 7: Driver enable and disable time
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ST485ERB
Test circuit and typical characteristics
Figure 8: Receiver propagation delay
Figure 9: Receiver enable and disable time
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Test circuit and typical characteristics
ST485ERB
Figure 10: Receiver output current vs. output low
voltage
Figure 11: Receiver output current vs. output high
voltage
Figure 12: Driver output current vs. output low voltage
Figure 13: Driver output current vs. output high voltage
Figure 14: Supply current vs. temperature
Figure 15: Receiver high level output voltage vs.
temperature
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ST485ERB
Test circuit and typical characteristics
Figure 16: Receiver low level output voltage vs.
temperature
Figure 17: Differential driver output voltage vs.
temperature
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Package information
6
ST485ERB
Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK ®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
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ST485ERB
6.1
Package information
SO8 package information
Figure 18: SO8 package outline
Table 9: SO8 mechanical data
Dimensions
Ref.
Millimeters
Min.
Typ.
A
Inches
Max.
Min.
Typ.
1.75
0.069
A1
0.10
A2
1.25
b
0.28
0.48
0.011
0.019
c
0.17
0.23
0.007
0.010
D
4.80
4.90
5.00
0.189
0.193
0.197
E
5.80
6.00
6.20
0.228
0.236
0.244
E1
3.80
3.90
4.00
0.150
0.154
0.157
e
0.25
Max
0.004
0.010
0.049
1.27
0.050
h
0.25
0.50
0.010
0.020
L
0.40
1.27
0.016
0.050
L1
k
ccc
1.04
0°
0.040
8°
0.10
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0°
8°
0.004
15/19
Package information
6.2
ST485ERB
SO8 tape and reel information
Figure 19: SO8 tape and reel outline
1.
Drawing not to scale
Table 10: SO8 tape and reel mechanical data
Dimensions
Symbol
mm
Min.
Typ.
A
Max.
Min.
Typ.
330
12.8
D
20.2
0.795
N
60
2.362
Ao
8.1
Bo
Ko
13.2
—
Max.
12.992
C
T
16/19
inch
0.504
22.4
0.519
—
0.882
8.5
0.319
5.5
5.9
0.216
0.232
2.1
2.3
0.082
0.090
Po
3.9
4.1
0.153
0.161
P
7.9
8.1
0.311
0.319
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0.335
ST485ERB
7
Ordering information
Ordering information
Table 11: Order code
Order code
Temperature range
Package
Packaging
ST485ERBDR
-40 to 85 °C
SO8 (tape and reel)
2500 parts per reel
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Revision history
8
ST485ERB
Revision history
Table 12: Document revision history
Date
Revision
Changes
21-Mar-2006
3
Order codes has been updated and new template.
01-Aug-2006
4
Mistake in cover page description 300 mA ==> 300 µA.
25-Oct-2006
5
Order codes updated.
02-Dec-2008
6
Modified: device name Table 1 on page 1.
16-Feb-2008
7
Modified Note on page 5.
Updated "Features": replaced “allows up to 256 transceivers on the
bus” by “64 transceivers”.
Table 6: "DC electrical characteristics": updated footnote 3
04-Oct-2016
18/19
8
Removed DIP package
Updated SO8 package
Removed “Device summary” table to Section 7: "Ordering
information".
Removed obsolete order code ST485ERBN
DocID9275 Rev 8
ST485ERB
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