STMICROELECTRONICS ST485CN

ST485B
ST485C
Low power RS-485/RS-422 transceiver
Features
■
Low quiescent current: 300 µA
■
Designed for RS-485 interface application
■
-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
■
Operate from a single 5 V supply
■
Current limiting and thermal shutdown for
driver overload protection
■
Allows up to 64 transceivers on the bus
DIP-8
SO-8
The ST485 is available in three temperature
range: commercial (0 °C to 70 °C), industrial (-40
°C to 85 °C) and automotive (-55 °C to 125 °C).
Description
The ST485 is al low power transceiver for RS-485
and RS-422 communication. Each part contains
one driver and one receiver.
This transceiver draw 300 µA (typ.) of supply
current when unloaded or fully loaded with
disabled drivers.
It operates from a single 5 V supply.
Driver is short-circuit current limited and is
protected against excessive power dissipation by
thermal shutdown circuitry that placed the driver
outputs into a high-impedance state.
The ST485 is designed for bi-directional data
communications on multipoint bus transmission
line (half-duplex applications).
Table 1.
Device summary
Order code
Temperature range
Package
Packaging
ST485CN
0 to 70 °C
DIP-8
50 parts per tube / 40 tube per box
ST485BN
-40 to 85 °C
DIP-8
50 parts per tube / 40 tube per box
ST485CDR
0 to 70 °C
SO-8 (tape and reel)
2500 parts per reel
ST485BDR
-40 to 85 °C
SO-8 (tape and reel)
2500 parts per reel
February 2008
Rev 15
1/19
www.st.com
19
Contents
ST485B - ST485C
Contents
1
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1
Driver switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2
Receiver switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5
Test circuit and typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2/19
ST485B - ST485C
Pin configuration
1
Pin configuration
Figure 1.
Pin connections
Table 2.
Pin description
Pin n°
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
3/19
Truth tables
ST485B - ST485C
2
Truth tables
Table 3.
Truth table (driver)
Inputs
Outputs
RE
DE
DI
B
A
X
H
H
L
H
X
H
L
H
L
X
L
X
Z
Z
Note:
X = Don’t care; Z = High impedance
Table 4.
Truth table (receiver)
Inputs
Note:
4/19
Outputs
RE
DE
A-B
L
L
L
L
≤-0.2V
L
L
L
Inputs open
H
H
L
X
Z
≥
X = Don’t care; Z = High impedance
+0.2V
RO
H
ST485B - ST485C
Maximum ratings
3
Maximum ratings
Table 5.
Absolute maximum ratings
Symbol
VCC
Parameter
Supply voltage
Value
Unit
7
V
VI
Control input voltage (RE, DE)
-0.5 to (VCC + 0.5)
V
VDI
Driver input voltage (DI)
-0.5 to (VCC + 0.5)
V
VDO
Driver output voltage (A, B)
± 14
V
VRI
Receiver input voltage (A, B)
± 14
V
VRO
Receiver output voltage (RO)
-0.5 to (VCC + 0.5)
V
Note:
Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied. V+ and V- can have a maximum
magnitude of +7 V, but their absolute addition can not exceed 13 V.
5/19
Electrical characteristics
ST485B - ST485C
4
Electrical characteristics
Table 6.
DC electrical characteristics
VCC = 5 V ± 5 %, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Value
Symbol
Parameter
Test conditions (1)
-40 to 85 °C
Min.
VOD1
Differential driver output
(no load)
VOD2
Differential driver output
(with load)
ΔVOD
Change in magnitude of
driver differential output
RL = 27Ω or 50Ω Figure 2
voltage for complementary
output states
VOC
Driver common-mode
output voltage
ΔVOC
Typ.
-55 to 125 °C
Max.
Min.
Max.
5
V
5
5
V
V
0.2
0.2
V
RL = 27Ω or 50Ω Figure 2
3
3
V
Change in magnitude of
driver common-mode
output voltage for
complementary output
states
RL = 27Ω or 50Ω Figure 2
0.2
0.2
V
VIH
Input high voltage
RE, DE, DI
VIL
Input low voltage
RE, DE, DI
0.8
0.8
V
IIN1
Input current
RE, DE, DI
±2
±2
µA
IIN2
Input current (A, B)
VCM = 0V or 5.25V, VDE = 0V
VIN = 12V
VIN = -7V
1
-0.8
1
-0.8
mA
mA
VTH
Receiver differential
threshold voltage
VCM = -7 to 12V
0.2
V
ΔVTH
Receiver input hysteresis
VCM = 0V
VOH
Receiver output high
voltage
IO = -4mA, VID = 200mV
VOL
Receiver output low
voltage
IO = 4mA, VID = -200mV
0.4
0.55
V
IOZR
3-state (high impedance)
output current at receiver
VO = 0.4 to 2.4V
±1
±1
µA
RIN
Receiver input resistance
VCM = -7 to 12V
ICC
No load supply current (2)
VRE = 0V or VCC
VDE = VCC
VDE = 0V
6/19
5
Unit
RL = 27Ω (RS-485) Figure 2
RL = 50Ω (RS-422) Figure 2
5
5
1.5
2.0
1.4
2.0
-0.2
0.2
-0.2
V
70
mV
3.5
3.4
24
V
24
400
300
900
500
KΩ
900
500
µA
µA
ST485B - ST485C
Table 6.
Electrical characteristics
DC electrical characteristics (continued)
VCC = 5 V ± 5 %, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Value
Symbol
Parameter
Test conditions (1)
-40 to 85 °C
Min.
Typ.
-55 to 125 °C
Max.
Min.
Max.
Unit
IOSD1
Driver short-circuit
current, VO=High
VO = -7 to 12V (3)
35
250
35
250
mA
IOSD2
Driver short-circuit
current, VO=Low
VO = -7 to 12V (3)
35
250
35
250
mA
IOSR
Receiver short-circuit
current
VO = 0V to VCC
7
95
7
95
mA
1. All currents into device pins are positive; all cuttents out of device pins are negative; all voltages are referenced to device
ground unless specified.
2. Supply current specification is valid for loaded transmitters when VDE = 0V
3. Applies to peak current. See typical Operating Characteristics.
Table 7.
Driver switching characteristics
VCC = 5 V ± 5 %, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred
to TA = 25 °C
Value
Symbol
Parameter
Test conditions (1)
-40 to 85 °C
-55 to 125°C
Min.
Unit
Min.
Typ.
Max.
Max.
10
30
60
70
ns
5
10
10
ns
15
40
45
ns
tPLH
tPHL
Propagation delay
input to output
RDIFF = 54Ω, CL1 = CL2 = 100pF
(See Figure 4 and Figure 6)
tSK
Output skew to output
RDIFF = 54Ω, CL1 = CL2 = 100pF
(See Figure 4 and Figure 6)
tTLH
tTHL
Rise or fall time
RDIFF = 54Ω, CL1 = CL2 = 100pF
(See Figure 4 and Figure 6)
tPZH
Output enable time
CL = 100pF, S2 = Closed
(See Figure 5 and Figure 7)
70
90
90
ns
tPZL
Output enable time
CL = 100pF, S1 = Closed
(See Figure 5 and Figure 7)
70
90
90
ns
tPLZ
Output disable time
CL = 15pF, S1 = Closed
(See Figure 5 and Figure 7)
70
90
90
ns
tPHZ
Output disable time
CL = 15pF, S2 = Closed
(See Figure 5 and Figure 7)
70
90
90
ns
3
3
1. All currents into device pins are positive; all cuttents out of device pins are negative; all voltages are referenced to device
ground unless specified.
7/19
Electrical characteristics
Table 8.
ST485B - ST485C
Receiver switching characteristics
VCC = 5 V ± 5%, TA = TMIN to TMAX, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Value
Symbol
Parameter
Test conditions (1)
-40 to 85 °C
Min.
Typ.
Max.
20
130
210
-55 to 125°C
Min.
Unit
Max.
tPLH
tPHL
Propagation delay input
to output
RDIFF=54Ω, CL1 = CL2 = 100pF
(See Figure 4 and Figure 8)
tSKD
Differential receiver
skew
RDIFF=54Ω, CL1 = CL2 = 100pF
(See Figure 4 and Figure 8)
13
tPZH
Output enable time
CRL = 15pF, S1 = Closed
(See Fig. 2 and Figure 9)
20
50
56
ns
tPZL
Output enable time
CRL = 15pF, S2 = Closed
(See Fig. 2 and Figure 9)
20
50
56
ns
tPLZ
Output disable time
CRL = 15pF, S1 = Closed
(See Fig. 2 and Figure 9)
20
50
56
ns
tPHZ
Output disable time
CRL = 15pF, S2 = Closed
(See Fig. 2 and Figure 9)
20
50
56
ns
fMAX
Maximum data rate
2.5
230
ns
ns
2.5
Mbps
1. All currents into device pins are positive; all cuttents out of device pins are negative; all voltages are referenced to device
ground unless specified
8/19
ST485B - ST485C
Test circuit and typical characteristics
5
Test circuit and typical characteristics
Figure 2.
Driver DC test load
Figure 3.
Receiver timing test load
Figure 4.
Drive/receiver timing test circuit
Figure 5.
Driver timing test load
9/19
Test circuit and typical characteristics
10/19
Figure 6.
Driver propagation delay
Figure 7.
Driver enable and disable time
ST485B - ST485C
ST485B - ST485C
Test circuit and typical characteristics
Figure 8.
Receiver propagation delay
Figure 9.
Receiver enable and disable time
11/19
Test circuit and typical characteristics
Figure 10. Receiver output current vs output
low voltage
ST485B - ST485C
Figure 11. Receiver output current vs output
high voltage
Figure 12. Driver output current vs output low Figure 13. Driver output current vs output
voltage
high voltage
Figure 14. Supply current vs temperature
12/19
Figure 15. Receiver high level output voltage
vs temperature
ST485B - ST485C
Figure 16. Receiver low level output voltage
vs temperature
Test circuit and typical characteristics
Figure 17. Differential driver output voltage vs
temperature
13/19
Package mechanical data
6
ST485B - ST485C
Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com
14/19
ST485B - ST485C
Package mechanical data
Plastic DIP-8 mechanical data
mm.
inch.
Dim.
Min.
A
Typ.
Max.
Min.
3.3
Typ.
Max.
0.130
a1
0.7
B
1.39
1.65
0.055
0.065
B1
0.91
1.04
0.036
0.041
b
b1
0.028
0.5
0.38
0.020
0.5
D
0.015
0.020
9.8
0.386
E
8.8
0.346
e
2.54
0.100
e3
7.62
0.300
e4
7.62
0.300
F
7.1
0.280
I
4.8
0.189
L
Z
3.3
0.44
0.130
1.6
0.017
0.063
P001F
15/19
Package mechanical data
ST485B - ST485C
SO-8 mechanical data
Dim.
mm.
Min.
Typ.
inch.
Max.
Min.
Typ.
Max.
A
1.35
1.75
0.053
0.069
A1
0.10
0.25
0.04
0.010
A2
1.10
1.65
0.043
0.065
B
0.33
0.51
0.013
0.020
C
0.19
0.25
0.007
0.010
D
4.80
5.00
0.189
0.197
E
3.80
4.00
0.150
0.157
e
1.27
0.050
H
5.80
6.20
0.228
0.244
h
0.25
0.50
0.010
0.020
L
0.40
1.27
0.016
0.050
k
ddd
8° (max.)
0.1
0.04
0016023/C
16/19
ST485B - ST485C
Package mechanical data
Tape & reel SO-8 mechanical data
mm.
inch.
Dim.
Min.
A
Typ.
Max.
Min.
330
Max.
12.992
C
12.8
D
20.2
0.795
N
60
2.362
T
13.2
Typ.
0.504
22.4
0.519
0.882
Ao
8.1
8.5
0.319
0.335
Bo
5.5
5.9
0.216
0.232
Ko
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
17/19
Revision history
ST485B - ST485C
7
Revision history
Table 9.
Document revision history
Date
Revision
21-Mar-2006
12
Order codes has been updated and new template.
02-Aug-2006
13
Mistake in cover page first row mA ==> µA.
08-Nov-2006
14
Added: Table 1.
07-Feb-2008
15
Modified: Table 1 on page 1.
18/19
Changes
ST485B - ST485C
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