ST3485EB, ST3485EC,
ST3485EI, ST3485EIY
3.3 V powered, 15 kV ESD protected, up to 12 Mbps RS-485/
RS-422 transceiver
Datasheet - production data
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
Available in SO8 package
Automotive grade (ST3485EIY)
Description
Features
ESD protection
±15 kV IEC 61000-4-2 air discharge
±8 kV IEC 61000-4-2 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
The ST3485EB/EC/EI/EIY device 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 device transmits and receives at a
guaranteed data rate of at least 12 Mbps.
All transmitter outputs and receiver inputs are
protected to ±15 kV IEC 61000-4-2 air discharge.
The 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.
Table 1: Device summary
Order code
ST3485ECDR
ST3485EBDR
ST3485EIDT
ST3485EIYDT
Temp. range
0 to 70 °C
-40 to 85 °C
-40 to 125 °C
SO8 (tape and reel)
2500 parts per reel
Package
Packing
October 2017
DocID9102 Rev 11
1/24
www.st.com
This is information on a product in full production.
Contents
ST3485EB, ST3485EC, ST3485EI, ST3485EIY
Contents
1
2
3
4
5
6
Pin configuration ............................................................................. 3
Truth tables ...................................................................................... 4
Maximum ratings ............................................................................. 5
Electrical characteristics ................................................................ 6
Test circuits and typical characteristics ...................................... 10
Package information ..................................................................... 19
6.1
6.2
SO8 package information ................................................................ 19
SO8 tape and reel information ........................................................ 20
7
8
Ordering information..................................................................... 21
Revision history ............................................................................ 22
2/24
DocID9102 Rev 11
ST3485EB, ST3485EC, ST3485EI, ST3485EIY
Pin configuration
1
Pin configuration
Figure 1: Pin connections
RO 1
RE 2
DE
DI
3
4
8
7
6
5
VCC
B
A
GND
Table 2: Pin description
Pin n°
1
Symbol
RO
Name and function
Receiver output. If A > B by 200 mV, RO will be high; if A < B by 200
mV, RO will be low.
Receiver output enable. RO is enabled when RE
2
RE
impedance when RE
is low; RO is high
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
3
DE
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
4
5
6
7
8
DI
GND
A
B
VCC
is low.
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.
Ground.
Non-inverting receiver input and non-inverting driver output.
Inverting receiver input and inverting driver output.
Supply voltage: V
CC
= 3 V to 3.6 V.
DocID9102 Rev 11
3/24
Truth tables
ST3485EB, ST3485EC, ST3485EI, ST3485EIY
2
Truth tables
Table 3: Truth table (driver)
Inputs
RE
X
L
H
DE
H
DI
H
L
X
B
L
H
Z
Outputs
Mode
A
H
L
Z
Normal
L
Shutdown
Note:
X = “don’t care”; Z = high impedance
Table 4: Truth table (receiver)
Inputs
RE
DE
A-B
≥ 0.2 V
L
L
≤ -0.2 V
Inputs open
X
Output
Mode
RO
H
L
H
Z
Shutdown
Normal
H
Note:
X = “don’t care”; Z = high impedance
4/24
DocID9102 Rev 11
ST3485EB, ST3485EC, ST3485EI, ST3485EIY
Maximum ratings
3
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 5: Absolute maximum ratings
Symbol
V
CC
V
I
V
DI
V
DO
V
RI
V
RO
Supply voltage
Control input voltage ( RE , DE)
Driver input voltage (DI)
Driver output voltage (A, B)
Receiver input voltage (A, B)
Receiver output voltage (RO)
HBM: human body model for the line inputs
(A and B)
(1)
HBM: human body model for the logic
ESD
inputs (DI, DE, RE )
(1)
HBM: human body model for all other pins
(1)
Parameter
Value
7
-0.3 to 7
-0.3 to 7
±14
±14
-0.3 to (V
CC
+ 0.3)
12
4
2
1.5
Unit
V
kV
CDM: charged device model
Notes:
(1)
Human
(2)
body model: 100 pF discharged through a 1.5 kΩ resistor between two pins of the device, done for
all couples of pin combinations with other pins floating.
(2)
Charged
device model: all pins plus package are charged together to the specified voltage and then
discharged directly to ground.
DocID9102 Rev 11
5/24
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
