STMICROELECTRONICS ST3485ECN

ST3485EB
ST3485EC
3.3 V powered, 15 kV ESD protected,
up to 12 Mbps RS-485/RS-422 transceiver
Features
■
ESD protection
– ±15 kV human body model
– ±8 kV IEC 1000-4-2 contact discharge
■
Operate from a single 3.3 V supply - no charge
pump required
■
Interoperable with 5 V logic
■
1 µA low current shutdown mode max
■
Guaranteed 12 Mbps data rate
■
-7 to 12 V common mode input voltage range
■
Half duplex versions available
■
Industry standard 75176 pinout
■
Current limiting and thermal shutdown for
driver overload protection
■
Guaranteed high receiver output state for
floating inputs with no signal present
■
Allow up to 64 transceivers on the bus
DIP-8
SO-8
Driver is short-circuit current limited and is
protected against excessive power dissipation by
thermal shutdown circuitry that places the driver
outputs into a high-impedance state.
Description
The ST3485E is ±15 kV ESD protected, 3.3 V low
power transceiver for RS-485 and RS-422
communications. The device contains one driver
and one receiver in half duplex configuration. The
ST3485E transmits and receives at a guaranteed
data rate of at least 12 Mbps.
All transmitter outputs and receiver inputs are
protected to ±15 kV using Human Body Model.
Table 1.
Device summary
Order code
Temperature range
Package
Packaging
ST3485ECN
0 to 70 °C
DIP-8
50 parts per tube / 40 tube per box
ST3485ECDR
0 to 70 °C
SO-8 (tape and reel)
2500 parts per reel
ST3485EBDR
-40 to 85 °C
SO-8 (tape and reel)
2500 parts per reel
November 2007
Rev 5
1/22
www.st.com
22
Contents
ST3485EB - ST3485EC
Contents
1
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Truth tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5
Test circuits and typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 9
6
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2/22
ST3485EB - ST3485EC
Pin configuration
1
Pin configuration
Figure 1.
Pin connections
Table 2.
Pin description
Pin n°
Symbol
Name and function
1
RO
Receiver output. If A>B by 200mV, RO will be high; if A<B by 200mV, RO will be low
2
RE
Receiver output enable. RO is enabled when RE is low; RO is high impedance when RE
is high. If RE is high and DE is low, the device will enter a low power shutdown mode.
3
DE
Driver output enable. The driver outputs are enabled by bringing DE high. They are high
impedance when DE is low. If RE is high DE is low, the device will enter a low-power
shutdown mode. If the driver outputs are enabled, the part functions as line driver, while
they are high impedance, it functions as line receivers if RE is low.
4
DI
Driver input. A low on DI forces output A low and output B high. Similarly, a high on DI
forces output A high and output B low
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: VCC= 3V to 3.6V
3/22
Truth tables
ST3485EB - ST3485EC
2
Truth tables
Table 3.
Truth table (driver)
Inputs
Outputs
Mode
RE
DE
DI
B
A
X
H
H
L
H
Normal
X
H
L
H
L
Normal
L
L
X
Z
Z
Normal
H
L
X
Z
Z
Shutdown
Note:
X= Don’t care; Z=High impedance
Table 4.
Truth table (receiver)
Inputs
Output
Mode
RE
DE
A-B
RO
L
L
≥ 0.2V
H
Normal
L
L
≤-0.2V
L
Normal
L
L
Inputs Open
H
Normal
H
L
X
Z
Shutdown
Note:
4/22
X= Don’t care; Z=High impedance
ST3485EB - ST3485EC
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)
-0.3 to 7
V
VDI
Driver input voltage (DI)
-0.3 to 7
V
VDO
Driver output voltage (A, B)
± 14
V
VRI
Receiver input voltage (A, B)
± 14
V
VRO
Receiver output voltage (RO)
-0.3 to (VCC + 0.3)
V
Note:
Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 6.
ESD performance: transmitter outputs, receiver inputs
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
ESD
ESD protection voltage
Human body model
± 15
kV
ESD
ESD protection voltage
IEC-1000-4-2 Contact discharge
±8
kV
5/22
Electrical characteristics
ST3485EB - ST3485EC
4
Electrical characteristics
Table 7.
Electrical characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Symbol
ISUPPLY
ISHDN
Table 8.
Symbol
Parameter
VCC Power supply current
Shutdown supply current
Test conditions
No Load, DI=0V or VCC
Parameter
Unit
DE=VCC,
RE=0V or VCC
1.3
2.2
mA
DE=0V,
RE=0V
1.2
1.9
mA
0.002
1
µA
Test conditions
DE, DI, RE
VIH
Input logic threshold high
DE, DI, RE
IIN1
Logic input current
DE, DI, RE
IIN2
Input current (A, B)
DE=0V, VCC= 0 or 3.6V
VOD
Max.
Logic input electrical characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Input logic threshold low
Symbol
Typ.
DE=0V, RE=VCC, DI=0V or VCC
VIL
Table 9.
Min.
Typ.
Max.
Unit
1.3
0.8
V
2
V
± 2.0
µA
VIN=12V
1
mA
VIN=-7V
-0.8
mA
Transmitter electrical characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25°C)
Parameter
Differential drive output
Test conditions
Min.
Typ.
Max.
Unit
RL= 100Ω (RS-422) (Figure 1)
2
V
RL= 54Ω (RS-485) (Figure 1)
1.5
V
RL= 60Ω (RS-485) (Figure 2)
1.5
V
ΔVOD
Change in magnitude of driver
differential output voltage for
RL= 54Ω or 100Ω (Figure 1)
complementary output states
(Note: 1)
VOC
Driver common mode output
voltage
ΔVOC
Change in magnitude of driver
common mode output voltage RL= 54Ω or 100Ω (Figure 1)
(Note: 1)
IOSD
Driver short circuit output
current
6/22
Min.
RL= 54Ω or 100Ω (Figure 1)
0.2
V
3
V
0.2
V
± 250
mA
ST3485EB - ST3485EC
Table 10.
Symbol
Electrical characteristics
Receiver electrical characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25°C)
Parameter
Test conditions
Min.
Typ.
Max.
Unit
0.2
V
VTH
Receiver differential
threshold voltage
VCM = -7V to 12V, DE = 0
ΔVTH
Receiver input hysteresis
VCM = 0V
VOH
Receiver output high
voltage
IOUT = -4mA, VID = 200mV
(Figure 8 and Figure 9)
VOL
Receiver output low
voltage
IOUT = 4mA, VID = -200mV, (Figure 3)
0.4
V
IOZR
3-State (high impedance)
output current at receiver
VCC = 3.6V, VO = 0V to VCC
±1
µA
RRIN
Receiver input resistance
VCM = -7V to 12V
24
IOSR
Receiver short-circuit
current
VRO = 0V to VCC
7
Table 11.
Symbol
-0.2
70
V
2
V
kΩ
60
mA
Driver switching characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Parameter
Test conditions
Min.
Typ.
12
15
Max.
Unit
DR
Maximum data rate
tDD
Differential output delay
RL= 60Ω, CL = 15pF, (Figure 4 and
Figure 5)
18
30
ns
tTD
Differential output
transition time
RL= 60Ω, CL = 15pF, (Figure 4 and
Figure 5)
12
20
ns
tPLH
tPHL
Propagation delay
RL= 27Ω, CL = 15pF, (Figure 8 and
Figure 9)
18
30
ns
tPDS
|tPLH - tPHL| Propagation
delay skew (Note 2)
RL= 27Ω, CL = 15pF, (Figure 8 and
Figure 9)
2
5
ns
tPZL
Output enable time
RL= 110Ω, (Figure 10 and Figure 11)
19
35
ns
tPZH
Output enable time
RL= 110Ω, (Figure 6 and Figure 7)
30
50
ns
tPHZ
Output disable time
RL= 110Ω, (Figure 6 and Figure 7)
19
35
ns
tPLZ
Output disable time
RL= 110Ω, (Figure 10 and Figure 11)
30
50
ns
Mbps
tSKEW
Differential output delay
skew
1
3
ns
tZH(SHDN)
Driver enable from
shutdown to output high
30
50
ns
tZL(SHDN)
Driver enable from
shutdown to output low
19
35
ns
7/22
Electrical characteristics
Table 12.
Symbol
tPLH
tPHL
ST3485EB - ST3485EC
Receiver switching characteristics
VCC = 3 V to 3.6 V, TA = -40 to 85 °C, unless otherwise specified. Typical values are referred
to TA = 25 °C)
Parameter
Test conditions
Min.
Typ.
Max.
Unit
Propagation delay
VID =0V to 3V, CL1 = 15pF
(Figure 12 and Figure 13)
30
50
ns
|tPLH - tPHL| Propagation
delay skew
VID =0V to 3V, CL1 = 15pF
(Figure 12 and Figure 13)
1
3
ns
tPZL
Output enable time
CRL = 15pF, (Figure 14 and Figure 18)
10
20
ns
tPZH
Output enable time
CRL = 15pF, (Figure 14 and Figure 18)
10
20
ns
tPHZ
Output disable time
CRL = 15pF, (Figure 14 and Figure 18)
10
20
ns
tPLZ
Output disable time
CRL = 15pF, (Figure 14 and Figure 18)
10
20
ns
tZH(SHDN)
Receiver enable from
shutdown to output high
CRL = 15pF, (Figure 14 and Figure 18)
10
20
ns
tZL(SHDN)
Receiver enable from
shutdown to output low
CRL = 15pF, (Figure 14 and Figure 18)
20
40
µs
tRPDS
Note:
8/22
1
ΔVOD and ΔVOC are the changes in VOD and VOC, respectively, when the DI input changes
state.
2
Measured on |tPLH(A)-tPHL(A)| and |tPLH(B)-tPHL(B)|
3
The transceivers are put into shutdown by bring RE high and DE low. If the input are in state
for less than 80 ns, the part are guaranteed not to enter shutdown. If the inputs are in this
state for at least 300 ns, the parts are guaranteed to have entered shutdown.
ST3485EB - ST3485EC
Test circuits and typical characteristics
5
Test circuits and typical characteristics
Figure 2.
Driver and VOC test load
Figure 3.
Driver VOD with varying common mode voltage test load
Figure 4.
Receiver VOH and VOL test circuit
9/22
Test circuits and typical characteristics
Figure 5.
Drive differential output delay transition time test circuit
Figure 6.
Drive differential output delay transition time waveform
Figure 7.
Drive enable and disable times test circuit
10/22
ST3485EB - ST3485EC
ST3485EB - ST3485EC
Figure 8.
Drive enable and disable times waveforms
Figure 9.
Drive propagation time test circuit
Test circuits and typical characteristics
Figure 10. Drive propagation time waveform
11/22
Test circuits and typical characteristics
Figure 11. Drive enable and disable times test circuit
Figure 12. Drive enable and disable times waveforms
Figure 13. Receiver propagation delay time test circuit
12/22
ST3485EB - ST3485EC
ST3485EB - ST3485EC
Test circuits and typical characteristics
Figure 14. Receiver propagation delay time waveforms
Figure 15. Receiver enable and disable times test circuit
Figure 16. Receiver enable and disable times waveform
13/22
Test circuits and typical characteristics
Figure 17. Receiver enable and disable times waveform
Figure 18. Receiver enable and disable times waveform
Figure 19. Receiver enable and disable times waveform
14/22
ST3485EB - ST3485EC
ST3485EB - ST3485EC
Test circuits and typical characteristics
Figure 20. Receiver output current vs output
low voltage
Figure 21. Receiver output current vs output
high voltage
Figure 22. Low level driver output capability
Figure 23. High level driver output capability
Figure 24. Receiver input characteristics
Figure 25. Driver short circuit current
15/22
Test circuits and typical characteristics
Figure 26. Driver short circuit current
16/22
ST3485EB - ST3485EC
ST3485EB - ST3485EC
6
Package mechanical data
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
17/22
Package mechanical data
ST3485EB - ST3485EC
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
18/22
ST3485EB - ST3485EC
Package mechanical data
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
19/22
Package mechanical data
ST3485EB - ST3485EC
Tape & reel SO-8 mechanical data
mm.
inch.
Dim.
Min.
A
Max.
Min.
330
13.2
Typ.
Max.
12.992
C
12.8
D
20.2
0.795
N
60
2.362
T
20/22
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
ST3485EB - ST3485EC
Revision history
7
Revision history
Table 13.
Document revision history
Date
Revision
Changes
20-Jun-2005
2
Mistake on table 12 tZL(SHDN) ms ==> µs.
30-Aug-2005
3
Remove (TRUE) on title, description has been updated in cover page.
The VTH and ΔVTH values are changed in table 10.
07-Apr-2006
4
Order codes updated.
12-Nov-2007
5
Added Table 1.
21/22
ST3485EB - ST3485EC
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22/22