The ST485E is al low power transceiver for
RS-485 and RS-422 communication. Each driver
output and receiver input is protected against
±15KV electrosta tic discharge (H.B.M.) (ESD)
shocks, without latcup. These parts contain one
ST485E
RS-485/RS-422 TRANSCEIVER
DIPSOP
driverandonereceiverinhalfduplex
configuration.
This transceiver draw 300µA (typ.) of sup ply
current when unlo aded or fully loaded with
disabled drivers.
It operates from a single 5V supply.
Driver is short-circuit current limited and is
protected against excessive power dissipation by
thermal shutdown circuitry th at place the driver
outputs into a high-impedance state.
The ST485E is designed f or bi-directional data
communications on multipoint bus transmission
line (half-duplex applications).
ORDERING CODES
Type
ST485ECN0 to 70 °CDIP-850parts per tube / 40tube per box
ST485EBN-40 to 85 °CDIP-850parts per tube / 40tube per box
ST485EXN-55 to 125 °CDIP-850parts per tube / 40tube per box
ST485ECD0 to 70 °CSO-8 (Tube)100parts per tube / 20tube per box
ST485EBD-40 to 85 °CSO-8 (Tube)100parts per tube / 20tube per box
ST485EXD-55 to 125 °CSO-8 (Tube)100parts per tube / 20tube per box
ST485ECDR0 to 70 °CSO-8 (Tape & Reel)2500 parts per reel
ST485EBDR-40 to 85 °CSO-8 (Tape & Reel)2500 parts per reel
ST485EXDR-55 to 125 °CSO-8 (Tape & Reel)2500 parts per reel
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.
Supply Voltage
CC
Control Input Voltage (RE, DE)-0.5 to (VCC+ 0.5)
I
Driver Input Voltage (DI)-0.5 to (VCC+ 0.5)
DI
Driver Output Voltage (A, B)
DO
Receiver Input Voltage (A, B)
RI
Receiver Output Voltage (RO)-0.5 to (VCC+ 0.5)
RO
7V
V
V
± 14V
± 14V
V
2/13
Page 3
ST485E
ESD PERFORMANCE: TRANSMITTER OUTPUTS, RE CEIVER INPUTS
SymbolParameterTest ConditionsMin.Typ.Max.Unit
ESDESD Protection VoltageHuman Body Model±15KV
ESDESD Protection VoltageIEC-1000-4-2±8KV
DC ELECTRICAL CHARACTERISTICS
=5V± 5%,TA=T
(V
CC
(See Note 1)
SymbolParameterTest ConditionsMin.Typ.Max.Unit
V
V
∆V
V
∆V
V
∆V
V
V
I
I
OSD1
I
OSD2
I
Note 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.
Note 2: Supply current specification is valid for loaded transmitters when V
Note 3: Applies to peak current. See typical Operating Characteristics.
Differential Driver Output
OD1
(No Load)
Differential Driver Output
OD2
(With Load)
Change in Magnitude of
OD
Driver Differential Output
Voltage for Complementary
Output States
Driver Common-Mode
OC
Output Voltage
Change in Magnitude of
OC
Driver Common-Mode
Output Voltage for
Complementary Output
States
V
Input High VoltageRE, DE, DI2.0V
IH
V
Input Low VoltageRE, DE, DI0.8V
IL
Input CurrentRE, DE, DI± 2µA
I
IN1
Input Current (A, B)VCM= 0V or 5.25VVDE=0V
I
IN2
Receiver Differential
TH
Threshold Voltage
Receiver Input HysteresisVCM=0V70mV
TH
Receiver Output High
OH
Voltage
Receiver Output Low
OL
Voltage
3-State (High Impedance)
OZR
Output Current at Receiver
R
Receiver Input ResistanceVCM= -7 to 12V24KΩ
IN
No Load Supply Current
I
CC
(Note 2)
Driver Short-Circuit Current,
=High
V
O
Driver Short-Circuit Current,
=Low
V
O
Receiver Short-Circuit
OSR
Current
MIN
to T
, unless otherwise spec ified. Typicalvalues are referred to TA= 25°C)
MAX
5V
RL=27Ω (RS-485) (See Fig. 1)
R
=50Ω (RS-422) (See Fig. 1)
L
=27Ω or 50Ω (See Fig. 1)0.2V
R
L
1.55
5
RL=27Ω or 50Ω (See Fig. 1)3V
=27Ω or 50Ω (See Fig. 1)0.2V
R
L
V
V
IN
IN
= 12V
= -7V
1
-0.8
VCM= -7 to 12V-0.20.2V
IO= -4mAVID= 200mV3.5V
IO=4mAVID= -200mV0.4V
VO= 0.4 to 2.4V± 1µA
VRE=0VorV
VDE=V
VDE=0V
V
= -7 to 12V (Note 3)35250mA
O
V
= -7 to 12V (Note 3)35250mA
O
VO=0VtoV
CC
CC
CC
DE
=0V
400
300
900
500
795mA
V
V
mA
mA
µA
µA
3/13
Page 4
ST485E
DRIVER S WITCHING CHARACTERISTICS
(V
=5V± 5%,TA=T
CC
(See Note 1)
SymbolParameterTest ConditionsMin.Typ.Max.Unit
t
t
t
t
t
t
t
Note 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.
Propagation Delay Input to
PLH
Output
t
PHL
t
Output Skew to OutputR
SK
Rise or Fall TimeR
TLH
THL
Output Enable TimeCL= 100pFS2 = Closed
PZH
Output Enable TimeCL= 100pFS1 = Closed
PZL
Output Disable TimeCL= 15pFS1= Closed
PLZ
Output Disable TimeCL= 15pFS2= Closed
PHZ
MIN
toT
,unless otherwise specified. Typical valu es arereferredto TA=25°C)
MAX
R
=54ΩCL1=CL2= 100pF
DIFF
2545ns
(See Fig. 3 and 5)
=54ΩCL1=CL2= 100pF
DIFF
25ns
(See Fig. 3 and 5)
=54ΩCL1=CL2= 100pF
DIFF
1540ns
(See Fig. 3 and 5)
3550ns
(See Fig. 4 and 6)
2540ns
(See Fig. 4 and 6)
2540ns
(See Fig. 4 and 6)
3550ns
(See Fig. 4 and 6)
RECEIVER SWITCHING CHARACTERISTICS
(V
=5V± 5%,TA=T
CC
MIN
to T
, unless otherwise spec ified. Typicalvalues are referred to TA= 25°C)
MAX
(See Note 1)
SymbolParameterTest ConditionsMin.Typ.Max.Unit
t
t
t
t
t
t
f
Note 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.
Propagation Delay Input to
PLH
Output
t
PHL
Differential Receiver SkewR
SKD
Output Enable TimeCRL= 15pFS2 = Closed
PZH
Output Enable TimeCRL= 15pFS1 = Closed
PZL
Output Disable TimeCRL= 15pFS1 = Closed
PLZ
Output Disable TimeCRL= 15pFS2 = Closed
PHZ
Maximum Data Rate5Mbps
MAX
R
=54ΩCL1=CL2= 100pF
DIFF
(See Fig. 3 and 7)
=54ΩCL1=CL2= 100pF
DIFF
(See Fig. 3 and 7)
(See Fig. 2 and 8)
(See Fig. 2 and 8)
(See Fig. 2 and 8)
(See Fig. 2 and 8)
110130ns
510ns
1135ns
1335ns
1335ns
1135ns
4/13
Page 5
TEST CIRCUITS AND TYPICAL CHARACTERISTICS
ST485E
Figure1 : Driver DC Test Load
Figure2 : Receiver Timing Test Load
Figure3 : Drive/Receiver Timing Test Circuit
Figure4 : Driver Timing Test Load
5/13
Page 6
ST485E
Figure5 : Driver Propagation D elay
Figure6 : Driver Enable an d Disable Time
6/13
Page 7
Figure7 : Receiver P ropagation Delay
Figure8 : Receiver E nable and Disable Time
ST485E
7/13
Page 8
ST485E
Figure9 : Receiver Output Current vs Output
Low Voltage
Figure10 : Receiver Output Current vs Out put
High Voltage
Figure12 : Driver Output Current vs Output High
Voltage
Figure13 : Su pply Current vs Temperature
Figure11 : Driver Output Current v s Output Low
Voltage
8/13
Figure14 : Receiver High Level Output Voltage
vs Temperature
Page 9
ST485E
Figure15 : Receiver Low Level Output Voltage
vs Temperature
Figure16 : Differential Driver Output V oltage v s
Temperature
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