ＳＴＣ Ｉ½½½½½½½½½½½½ Ｌ½½½½½½ ½½½½：／／½½½．½½½－½½½½½½．½½½
STC3485E
General Description
3.3V-Powered, ±
15kV ESD-Protected,
and Slew-Rate-Limited True RS-485 Transceivers
The STC3485E is +15 KV ESD protected, slew-rate limited, ultra lower differential line transceivers which provide full RS485 compat-
ibility while operating from single 3.3V supply. Each part contains one driver and one receiver, which is designed for data transmission
with extended common mode range (-7V to 12V). The STC3485E features slew-rate limited driver that minimizes EMI and reduces
reflections caused by improperly terminated cables, allowing error-free data transmission at data rate up to 500kbps.
All devices feature enhanced electrostatic discharge (ESD) protection. All transmitter outputs and receiver inputs are protected to
±
15kV using IEC 1000-4-2 Air-Gap Discharge and ±
15kV using the Human Body Model.
Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that
places the driver outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if
both inputs are open, shorted or idle.
Both parts have power up/down glitch free driver outputs permit live insertion or removal of transceiver from/to data bus. The
CMOS design offers significant power savings without sacrificing ruggedness against overload or ESD damage. Typical quiescent
current is only 500 µ while operating and 1 µ in shutdown.
A
A
The STC3485E are fully specified over the commercial an extended industrial temperature range and are available in 8-pin and DIP
packages.
Applications
Telecommunications
Low-Power RS-485 Transceivers
Integrated Services Digital Networks
Transceivers for EMI-Sensitive Applications
Packet Switching
Features
ESD Protection for RS-485 I/O Pins
±
15kV— Human Body Model
±
15kV— IEC 1000-4-2, Air-Gap Discharge
Operate from a Single 3.3V supply
Interoperable with +5V Logic
Slew-Rate Limited for Errorless Data Transmission
1 µ Low-Current Shutdown Mode
A
– to +12V Common-Mode Input Voltage Range
7V
Allows up to 256 Transceivers on the Bus
Thermal Shutdown
Current-Limiting for Driver Overload Protection
Ordering Information
PART
STC3485EESA
STC3485EEPA
TEMP. RANGE
-40° to +85°
C
C
-40° to +85°
C
C
PIN-PACKAGE
8 SO
8 Plastic DIP
ＳＴＣ３４８５Ｅ Ｄ½½½½½½½½ Ｒ½½．０．１， Ｄ½½．２００５
Ｐ½½½ ½½ １１
１
ＳＴＣ Ｉ½½½½½½½½½½½½ Ｌ½½½½½½ ½½½½：／／½½½．½½½－½½½½½½．½½½
Selector Guide
PART
NUMBER
STC3485E
GUARANTEED
DATA RATE
(Mbps)
0.5
SUPPLY
VOLTAGE
(V)
3.0 to 3.6
SLEW-RATE
LIMITED
Yes
DRIVER/
RECEIVER
ENABLE
Yes
SHUTDOWN
CURRENT
(µA)
1
±
15kV
ESD
PROTECTION
Yes
PIN
COUNT
8
Absolute Maximum Ratings
Supply Voltage (VCC) … … … … … … … … … … … … … … … … … … 5V
Control Input Voltage (/RE, DE) … … … … … … … … … … … -0.3V to 5V
Driver Input Voltage (DI) … … … … … … … … … … … … … … -0.3V to 5V
Driver Output Voltage (A, B) … … … … … … … … … … … … -7V to 12V
Receiver Input Voltage (A, B) … … … … … … … … … … … … -7V to 12V
Receiver Output Voltage (RO) … … … … … … … -0.3V to (VCC + 0.3V)
Continuous Power Dissipation (TA = +70°
C)
8-Pin Plastic DIP (derate 9.09mW/° above +70° … … … … 727mW
C
C)
8-Pin SO (derate 5.88mW/° above +70° … … … … … … … … 471mW
C
)
Operating Temperature Ranges
STC3485EE_ _ … … … … … … … … … … … … … … … -40° to +85°
C
C
Storage Temperature Range… … … … … … … … … … -65° to +160°
C
C
Lead Temperature (soldering, 10sec) … … … … … … … … … … +300°
C
Stresses beyond those listed under “
Absolute Maximum Ratings”may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not
implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC Electrical Characteristics
(V
CC
= 3.3V ±
0.3V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°
C)
PARAMETER
Differential Driver Output
Change in Magnitude of Driver Differential
Output Voltage for Complementary Output
States (Note 1)
Driver Common-Mode Output Voltage
Change in Magnitude of
Common-Mode Output Voltage
(Note 1)
Input High Voltage
Input Low Voltage
Logic Input Current
Input Current (A, B)
Receiver Differential
Threshold Voltage
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State (High Impedance)
Output Current at Receiver
Receiver Input Resistance
V
IH
V
IL
I
IN1
I
IN2
V
TH
?V
TH
V
OH
V
OL
I
OZR
R
IN
DE = 0V,
V
CC
= 0V or 3.6V
DE, DI, /RE
DE, DI, /RE
DE, DI, /RE
V
IN
= 12V
V
IN
= -7V
-0.2
20
V
CC
- 0.4
0.4
±1
96
2.0
0.8
±2
1.0
-0.8
-0.05
V
V
µA
mA
V
mV
V
V
µA
kO
?V
OC
R
L
= 54Oor 100O, Figure 2
0.2
V
V
OC
R
L
= 54O?r 100O, Figure 2
o
2
V
?V
OD
R
L
= 54O?r 100O, Figure 2
o
0.2
V
SYMBOL
V
OD
CONDITIONS
R
L
= 54O ?
(RS-485), Figure 2
R
L
= 60O ?
(RS-485), V
CC
= 3.3V, Figure3
MIN
1.2
1.2
TYP
MAX UNITS
V
-7V≤V
CM
≤12V
V
CM
= 0V
I
OUT
= -1.5mA, V
ID
= 200mV, Figure 4
I
OUT
= 2.5mA, V
ID
= 200mV, Figure 4
V
CC
= 3.6V, 0V≤V
OUT
≤V
CC
-7V≤V
CM
≤12V
No load,
DI = 0V or V
CC
DE = V
CC
, /RE = 0V or V
CC
DE = 0V, /RE = 0V
V
OUT
= -7V
V
OUT
= 12V
0V≤V
RO
≤V
CC
Supply Voltage Range
Supply Current
Supply Current in Shutdown Mode
Driver Short-Circuit Output Current
Receiver Short-Circuit Output Current
V
CC
I
CC
I
SHDN
I
OSD
I
OSR
3.0
0.6
0.5
1.0
3.6
1.2
1.0
-250
250
V
mA
µA
mA
mA
DE = 0V, /RE = V
CC
, DI = V
CC
or 0V
±8
±60
ESD Protection for A, B
Human Body Model
IEC 1000-4-2 Air Discharge
±
15
±
15
kV
ＳＴＣ３４８５Ｅ Ｄ½½½½½½½½ Ｒ½½．０．１， Ｄ½½．２００５
Ｐ½½½ ½½ １１
２
ＳＴＣ Ｉ½½½½½½½½½½½½ Ｌ½½½½½½ ½½½½：／／½½½．½½½－½½½½½½．½½½
Receiver Switching Characteristics
(V
CC
= 3.3V, T
A
= +25°
C)
PARAMETER
SYMBOL
t
DD
t
TD
t
PLH
t
PHL
t
PDS
t
PZL
t
PZH
t
PHZ
t
PLZ
t
PSL
t
PSH
CONDITIONS
R
L
= 60
O
, Figure 5
R
L
= 60
O
, Figure 5
R
L
= 27
O
, Figure 6
R
L
= 27
O
, Figure 6
R
L
= 27
O
, Figure 6
R
L
= 110
O
, Figure 8
R
L
= 110
O
, Figure 7
R
L
= 110
O
, Figure 7
R
L
= 110
O
, Figure 8
R
L
= 110
O
, Figure 8
R
L
= 110
O
, Figure 7
MIN
0.5
600
400
700
700
TYP MAX
900
740
930
930
±50
900
600
50
50
1.9
2.2
1300
800
80
80
2.7
3.0
1400
1200
1500
1500
UNITS
Mbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
µ
s
µ
s
Maximum Data Rate
Driver Differential Output Delay
Driver Differential Output Transition Time
Driver Propagation Delay, Low-to-High Level
Driver Propagation Delay, High-to-Low Level
|t
PLH
- t
PHL
| Driver Propagation Delay Skew (Note 2)
DRIVER-OUTPUT ENABLE/DISABLE TIMES
Driver Output Enable Time to Low Level
Driver Output Enable Time to High Level
Driver Output Disable Time from High Level
Driver Output Disable Time from Low Level
Driver Output Enable Time from Shutdown to Low Level
Driver Output Enable Time from Shutdown to High Level
Receiver Switching Characteristics
(V
CC
= +3.3V, T
A
= +25°
C.)
PARAMETER
Time to Shutdown
Receiver Propagation Delay,
Low-to-High Level
Receiver Propagation Delay,
High-to-Low Level
SYMBOL
t
SHDN
t
RPLH
CONDITIONS
(Note 3)
V
ID
= 0 to 3.0V, C
L
= 15pF, Figure 9
STC3485E
V
ID
= 0 to 3.0V, C
L
= 15pF, Figure 9
STC3485E
V
ID
= 0 to 3.0V, C
L
= 15pF, Figure 9
t
RPDS
STC3485E
t
PRZL
t
PRZH
t
PRHZ
t
PRLZ
t
PRSL
t
PRSH
C
L
= 15pF, Figure 10,
STC3485E
C
L
= 15pF, Figure 10,
STC3485E
C
L
= 15pF, Figure 10,
STC3485E
C
L
= 15pF, Figure 10,
STC3485E
C
L
= 15pF, Figure 12,
STC3485E
C
L
= 15pF, Figure 10,
STC3485E
12
25
25
25
25
720
720
±
20
50
50
45
45
1400
1400
ns
ns
ns
ns
ns
ns
MIN
80
25
25
25
25
TYP
190
62
75
62
75
6
MAX
300
90
120
90
120
±
10
ns
UNITS
ns
ns
t
RPHL
ns
|
t
PLH
- t
PHL
|
Receiver
Propagation-Delay Skew
Receiver-Output Enable Time
to Low Level
Receiver-Output Enable Time
to High Level
Receiver-Output Disable
Time from High Level
Receiver-Output Disable
Time from Low Level
Receiver-Output Enable Time
from Shutdown to Low Level
Receiver-Output Enable Time
from Shutdown to High Level
Note 1:
? V
OD
and ? V
OC
are the changes in V
OD
and V
OC
, respectively, when the DI input changes state.
Note 2:
Measured on |tPLH (Y) - tPHL (Y)| and |tPLH (Z) - tPHL (Z)|.
Note 3:
The transceivers are put into shutdown by bringing /RE high and DE low. If the inputs are in this state for less than 80ns, the
parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 300ns, the parts are guaranteed to have entered
shutdown. See Low-Power Shutdown Mode section.
ＳＴＣ３４８５Ｅ Ｄ½½½½½½½½ Ｒ½½．０．１， Ｄ½½．２００５
Ｐ½½½ ½½ １１
３
ＳＴＣ Ｉ½½½½½½½½½½½½ Ｌ½½½½½½ ½½½½：／／½½½．½½½－½½½½½½．½½½
Typical Operating Characteristics
(V
CC
= 3.3V, T
A
= +25° unless otherwise noted.)
C,
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ ½½．
ＲＥＣＥＩＶＥＲ ＯＵＴＰＵＴ ＬＯＷ ＶＯＬＴＡＧＥ
２５
－２０
－１８
２０
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ（½Ａ）
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ（½Ａ）
－１６
－１４
－１２
－１０
－８
－６
－４
－２
０
０
０．５
１．０
１．５
２．０
２．５
３．０
３．５
０
０
０．５
１．０
１．５
２．０
２．５
３．０
３．５
ＯＵＴＰＵＴ ＨＩＧＨＶＯＬＴＡＧＥ（Ｖ）
３．２５
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ ½½．
ＲＥＣＥＩＶＥＲ ＯＵＴＰＵＴ ＨＩＧＨ ＶＯＬＴＡＧＥ
ＲＥＣＥＩＶＥＲ ＯＵＴＰＵＴ ＨＩＧＨ ＶＯＬＴＡＧＥ
½½．ＴＥＭＰＥＲＡＴＵＲＥ
３．３０
３．２０
３．１５
３．１０
３．０５
３．００
－４０
１５
１０
５
－２０
０
２０
４０
６０
８０
１００
ＯＵＴＰＵＴ ＬＯＷ ＶＯＬＴＡＧＥ （Ｖ）
ＲＥＣＥＩＶＥＲ ＯＵＴＰＵＴ ＬＯＷ ＶＯＬＴＡＧＥ
½½．ＴＥＭＰＥＲＡＴＵＲＥ
０．８
０．７
ＯＵＴＰＵＴ ＬＯＷ ＶＯＬＴＡＧＥ（Ｖ）
０．６
０．５
０．４
０．３
０．２
０．１
０
－４０
－２０
０
２０
４０
６０
８０
１００
ＯＵＴＰＵＴ ＶＯＬＴＡＧＥ（½Ａ）
ＯＵＴＰＵＴ ＨＩＧＨ ＶＯＬＴＡＧＥ （Ｖ）
ＤＲＩＶＥＲ ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ ½½．
ＤＩＦＦＥＲＥＮＴＩＡＬ ＯＵＴＰＵＴ ＶＯＬＴＡＧＥ
１００
ＤＩＦＦＥＲＥＮＴＩＡＬ ＯＵＴＰＵＴ ＶＯＬＴＡＧＥ（Ｖ）
９０
８０
７０
６０
５０
４０
３０
２０
１０
０
０
０．５
１．０
１．５
２．０
２．５
３．０
３．５
Ｔ Ｅ Ｍ Ｐ Ｅ Ｒ Ａ Ｔ Ｕ Ｒ Ｅ （℃）
ＤＲＩＶＥＲ ＤＩＦＦＥＲＥＮＴＩＡＬ ＯＵＴＰＵＴ
ＶＯＬＴＡＧＥ ½½．ＴＥＭＰＥＲＡＴＵＲＥ
２．６
２．５
２．４
２．３
２．２
２．１
２．０
１．９
１．８
１．７
１．６
－４０
－２０
０
２０
４０
６０
８０
１００
Ｔ Ｅ Ｍ Ｐ Ｅ Ｒ Ａ Ｔ Ｕ Ｒ Ｅ （℃）
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ ½½．
ＤＲＩＶＥＲ ＯＵＴＰＵＴ ＬＯＷ ＶＯＬＴＡＧＥ
１７５
１５０
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ（½Ａ）
ＤＩＦＦＥＲＥＮＴＩＡＬ ＯＵＴＰＵＴ ＶＯＬＴＡＧＥ（Ｖ）
Ｔ Ｅ Ｍ Ｐ Ｅ Ｒ Ａ Ｔ Ｕ Ｒ Ｅ （℃）
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ ½½．
ＤＲＩＶＥＲ ＯＵＴＰＵＴ ＨＩＧＨ ＶＯＬＴＡＧＥ
－１００
－８０
ＯＵＴＰＵＴ ＣＵＲＲＥＮＴ（½Ａ）
０
２
４
６
８
１０
１２
１２５
１００
７５
５０
２５
０
ＯＵＴＰＵＴ ＬＯＷ ＶＯＬＴＡＧＥ（Ｖ）
ＳＵＰＰＬＹ ＣＵＲＲＥＮＴ
½½．ＴＥＭＰＥＲＡＴＵＲＥ
－６０
－４０
－２０
０
－７ －６ －５ －４ －３ －２ －１
０
１
２
３
４
５
ＯＵＴＰＵＴ ＨＩＧＨ ＶＯＬＴＡＧＥ（Ｖ）
ＳＨＵＴＤＯＷＮ ＣＵＲＲＥＮＴ
½½．ＴＥＭＰＥＲＡＴＵＲＥ
１００
９０
１．２
１．１
ＳＵＰＰＬＹ ＣＵＲＲＥＮＴ（½Ａ）
ＳＨＵＴＤＯＷＮ ＣＵＲＲＥＮＴ（½Ａ）
８０
７０
６０
５０
４０
３０
２０
１０
１．０
０．９
０．８
０．７
－４０
－２０
０
２０
４０
６０
８０
１００
０
－４０
－２０
０
２０
４０
６０
８０
１００
Ｔ Ｅ Ｍ Ｐ Ｅ Ｒ Ａ Ｔ Ｕ Ｒ Ｅ （℃）
Ｔ Ｅ Ｍ Ｐ Ｅ Ｒ Ａ Ｔ Ｕ Ｒ Ｅ （℃）
ＳＴＣ３４８５Ｅ Ｄ½½½½½½½½ Ｒ½½．０．１， Ｄ½½．２００５
Ｐ½½½ ½½ １１
４
ＳＴＣ Ｉ½½½½½½½½½½½½ Ｌ½½½½½½ ½½½½：／／½½½．½½½－½½½½½½．½½½
Pin Description
PIN
NAME
RO
/RE
FUNCTION
Receiver Output. If A > B by -50mV, RO will be high; if A < B by 200mV, RO will be low.
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.
Driver Output Enable. The driver outputs are enabled by bringing DE high. They are high impedance
when DE is low. If /RE is high and DE is low, the device will enter a low-power shutdown mode. If the
driver outputs are enabled, the parts function as line drivers. While they are high impedance, they
function as line receivers if /RE is low.
Driver Input. A low on DI forces output B high and output A low. Similarly, a high on DI forces output
B low and output A high.
Ground
Noninverting Receiver Input and Noninverting Driver Output
Inverting Receiver Input and Inverting Driver Output
Positive Supply: 3.0V≤V
CC
≤3.6V
1
2
3
DE
4
5
6
7
8
DI
GND
A
B
V
CC
ＴＯＰ ＶＩＥＷ
ＳＴＣ３４８５Ｅ
ＲＯ １
ＲＥ ２
ＤＥ ３
ＤＩ ４
Ｄ
ＳＯ／ＤＩＰ
Ｒ
８ Ｖ½½
７ Ｂ
６ Ａ
５ ＧＮＤ
ＲＯ １
ＲＥ ２
ＤＥ ３
ＤＩ ４
Ｄ
Ｒ
８ Ｖ½½
７ Ｂ
６
Ａ
５ ＧＮＤ
Ｂ
Ｒ½
Ｒ½
Ａ
Ｒ
ＤＥ
Ｄ
ＤＩ
ＲＯ
ＲＥ
Figure 1. STC3485E Pin Configuration and Typical Operating Circuit
３７５ Ω
Ｒ
Ｌ
２
Ｄ
Ｖ
ＣＣ
Ｖ
ＤＤ
Ｒ
Ｌ
２
Ｄ
Ｖ
ＣＣ
Ｖ
ＣＣ
３７５ Ω
Ｖ
ＤＤ
Ｒ
Ｌ
Ｖ
ＣＭ
＝
－７Ｖ ½½ ＋１２Ｖ
Figure 2. Driver V
OD
and V
OC
Figure 3. Driver V
OD
with Varying Common-Mode Voltage
Ｖ
ＩＤ
ＯＶ
Ｒ
Ｖ
ＯＬ
Ｉ
ＣＬ
（＋）
Ｖ
ＯＨ
Ｉ
ＯＨ
（－）
Figure 4. Receiver V
OH
and V
OL
ＳＴＣ３４８５Ｅ Ｄ½½½½½½½½ Ｒ½½．０．１， Ｄ½½．２００５
Ｐ½½½ ½½ １１
５
京公网安备 11010802033920号
EEWORLD
