UM3087E
±
15kV ESD-Protected, Fail-Safe, Hot-Swappable
Auto Polarity Reversal RS-485 Transceivers
UM3087E SOP8/DIP8
General Description
The UM3087E series are +5.0V powered ±
15kV ESD protected, fail-safe, hot-swappable, auto
polarity reversal RS-485 transceivers. The device includes fail-safe circuitry, which guarantees a
logic-high receiver output when the receiver inputs are open, shorted or idle. This means that the
receiver output will be logic high if all transmitters on a terminated bus are disabled (high
impedance). The UM3087E features reduced slew-rate driver that minimizes EMI and reduces
reflections caused by improperly terminated cables, allowing error-free data transmission up to
500kbps. All transmitter outputs and receiver inputs are protected to ±
15kV using the Human
Body Model and IEC61000-4-2, Air-Gap Discharge.
The UM3087E includes cable auto-invert functions that reverse the polarity of the RS485 bus pins
in case the cable is misconnected. Receiver’s full fail-safe features are maintained even when the
receiver polarity has been reversed.
The transceivers typically draw 300μA of supply current when unloaded, or when fully loaded
with the drivers disabled. The device has a 1/8-unit-load receiver input impedance that allows up
to 256 transceivers on the bus and is intended for half-duplex communications.
Applications
Smart Meters/Automated Meter
Reading Systems
Industrial-Control Local Area
Networks
PROFIBUS® and Other RS-485 Based
Field Bus Networks
Building Lighting and Environmental
Control Systems
Transceivers for EMI-Sensitive
Applications
Features
Automatic Polarity Reversal RS-485
Transceivers
I/O logic compatible with +5V, +3.3V &
+1.8V logic
ESD Protection for RS-485 I/O Pins
±
15kV—IEC61000-4-2, Air-Gap Discharge
±
8kV—IEC61000-4-2, Contact Discharge
True Fail-Safe Receiver
Enhanced Slew-Rate Limiting
Allows up to 256 Transceivers on the Bus
Thermal Shutdown
Current-Limiting for Driver Overload
Protection
Pin Configurations
RO
RE
DE
DI
V
CC
L1
L2
GND
Top View
XXXXXX
XXXX
XX
Ordering Information
Part Number
UM3087EESA
UM3087EEPA
Marking Code
UM3087EESA
UM3087EEPA
Operating Temperature
-40° to +85°
C
C
-40° to +85°
C
C
Package Type
SOP8
DIP8
________________________________________________________________________
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UM3087E
Absolute Maximum Ratings
Symbol
V
CC
Parameter
Supply Voltage
Control Input Voltage (/RE, DE)
Driver Input Voltage (DI)
Driver Output Voltage (L1, L2)
Receiver Input Voltage (L1, L2)
Receiver Output Voltage (RO)
T
A
T
STG
T
L
Ambient Temperature
Storage Temperature Range
Lead Temperature for Soldering 10 seconds
Value
+7
-0.3V to (V
CC
+ 0.3V)
-0.3V to (V
CC
+ 0.3V)
-7.5 to +12.5
-7.5 to +12.5
-0.3V to (V
CC
+ 0.3V)
-40 to +85
-65 to +160
+300
Unit
V
V
V
V
V
V
°
C
°
C
°
C
DC Electrical Characteristics
(V
CC
= +5V ± 5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V
and T
A
= +25° (Note 1)
C.)
Parameter
SUPPLY CURRENT
DE=V
CC
,
Supply Current
I
CC
No load,
R E =0V or V
CC
DI = GND
DE=0V,
or V
CC
______
R E =0V
______
______
Symbol
Test Conditions
Min
Typ
Max
Unit
0.3
mA
0.25
0.002
10
µ
A
Supply Current in Shutdown
Mode
LOGIC
Input High Voltage
Input Low Voltage
DI Input Hysteresis
DRIVER
Differential Driver Output
Differential Driver Output
Change-in-Magnitude of
Differential Output Voltage
Driver Common-Mode
Output Voltage
Change-in-Magnitude of
Common-Mode Voltage
Driver Short-Circuit Output
Current (Note 3)
I
SHDN
DE=GND, R E =V
CC
______
V
IH1
V
IL1
V
HYS
DE, DI, R E
______
2.0
0.4
100
V
V
mV
DE, DI, R E
V
OD1
V
OD2
ΔV
OD
V
OC
ΔV
OC
No Load, Figure 2
Figure 2, R = 54Ω
Figure 2, R = 54Ω;
(Note 2)
Figure 2, R = 54Ω
Figure 2, R = 54Ω;
(Note 2)
V
OUT
= -7V
4.9
2.0
2.2
5
V
V
0.2
3.0
0.2
-250
V
V
V
I
OSD
V
OUT
= 12V
250
mA
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UM3087E
DC Electrical Characteristics (Continued)
(V
CC
= +5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and
T
A
= +25° (Note 1)
C.)
Parameter
RECEIVER
Receiver Differential
Threshold Voltage
Receiver Input Hysteresis
Receiver Input Resistance
V
TH
ΔV
TH
R
IN
-7V≤V
CM
≤12V
V
CM
=0V
-7V≤V
CM
≤12V
DE = GND,
V
CC
= GND or
5V
V
IN
= 12V
V
IN
= -7V
96
1.0
mA
-0.8
V
0.4
±
1
V
µ
A
-200
25
-50
mV
mV
KΩ
Symbol
Test Conditions
Min
Typ
Max
Unit
Input Current (L1 and L2)
I
IN2
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State Output Current at
Receiver
Receiver Output Short Circuit
Current
ESD Protection
ESD Protection for A, B
V
OH
V
OL
I
OZR
I
O
= -1.5mA, V
ID
= 200mV V
CC
-1.5
I
O
= 2.5mA, V
ID
= 200mV
0V ≤ V
O
≤ V
CC
I
OSR
0V≤V
RO
≤V
CC
±
8
±
60
mA
Human Body Model
IEC61000-4-2 Air Discharge
IEC61000-4-2 Contact
±
15
±
15
±
8
kV
Note 1: All currents into the device are positive; all currents out of the device are negative. All
voltages are referred to device ground unless otherwise noted.
Note 2: ΔV
OD
and ΔV
OC
are the changes in V
OD
and V
OC
, respectively, when the DI input changes
state.
Note 3: Maximum current level applies to peak current just prior to fold back current limiting;
minimum current level applies during current limiting.
________________________________________________________________________
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UM3087E
Switching Characteristics
(V
CC
= +5V ± 5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V
and T
A
= +25°
C.)
Parameter
Maximum Data Rate
Driver Input-to-Output
t
DPHL
Driver Output Skew
| t
DPLH
- t
DPHL
|
Driver Rise or Fall Time
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from
Low
Driver Disable Time from
High
Receiver Input to Output
Differential
Receiver Skew
| t
RPLH
- t
RPHL
|
Receiver Enable to Output
Low
Receiver Enable to Output
High
Receiver Disable Time from
Low
Receiver Disable Time from
High
Time to Shutdown
Driver Enable from
Shutdown to Output High
Driver Enable from
Shutdown to Output Low
Receiver Enable from
Shutdown to Output High
Receiver Enable from
Shutdown to Output Low
t
DSKEW
t
DR
, t
DF
t
DZH
t
DZL
t
DLZ
t
DHZ
t
RPLH
,
t
RPHL
t
RSKD
Symbol
f
MAX
t
DPLH
Figures 3 and 7, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 3 and 7, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 3 and 7, R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF
Figures 4 and 8, C
L
= 100pF,
S2 closed
Figures 4 and 8, C
L
= 100pF,
S1 closed
Figures 4 and 8, C
L
= 15pF,
S1 closed
Figures 4 and 8, C
L
= 15pF,
S2 closed
| V
ID
| ≥2.0V;
rise and fall time of V
ID
≤15ns
Figures 6 and 9; | V
ID
| ≥2.0V;
rise and fall time of V
ID
≤15ns
Figures 5 and 10, C
L
= 100pF,
S1 closed
Figures 5 and 10, C
L
= 100pF,
S2 closed
Figures 5 and 10, C
L
= 100pF,
S1 closed
Figures 5 and 10, C
L
= 100pF,
S2 closed
(Note 4)
Figures 4 and 8, C
L
= 15pF,
S2 closed
Figures 4 and 8, C
L
= 15pF,
S1 closed
Figures 5 and 10, C
L
= 100pF,
S2 closed
Figures 5 and 10, C
L
= 100pF,
S1 closed
_______
Test Conditions
Min
Typ
500
Max
Unit
kbps
250
250
720
720
3
1000
ns
1000
100
750
2500
2500
100
100
ns
ns
ns
ns
ns
ns
ns
200
530
127
200
3
30
ns
t
RZL
t
RZH
t
RLZ
t
RHZ
t
SHDN
t
DZH(SHDN)
t
DZL(SHDN)
t
RZH(SHDN)
t
RZL(SHDN)
20
20
20
20
50
200
50
50
50
50
600
4500
4500
3500
3500
ns
ns
ns
ns
ns
ns
ns
ns
ns
Note 4: The device is put into shutdown by bringing R E high and DE low. If the enable inputs
are in this state for less than 50ns, the device is guaranteed not to enter shutdown. If the enable
inputs are in this state for at least 600ns, the device is guaranteed to have entered shutdown.
________________________________________________________________________
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UM3087E
Non-Polarity Features
_____
The Polarities of driver and receiver is always kept the same status. When DE=RE=LOGIC 0 and
RO is standing LOGIC 0 for T
S
time, the polarities will be reversed
automatically.
Parameter
Symbol
Test Conditions
Min Typ Max Unit
Waiting Time for Inverting
T
s
______
DE=R E =L, RO keeps L
150
200
250
ms
Pin Description
Pin
Number
1
2
Symbol
RO
______
Function
Receiver Output.
______
Receiver Enable. Drive R E low to enable Receiver, RO is high
______
______
RE
impedance when R E is high. Drive R E high and DE low to
enter low-power shutdown mode.
Driver Enable. Drive DE high to enable drivers. The outputs are
______
3
4
5
6
DE
DI
GND
L2
high impedance when DE is low. Drive R E high and DE low to
enter low-power shutdown mode.
Driver Input.
Ground
RS485 Receiver Input and Driver Output Pin. Normally L2 is
non inverting Bus I/O for transceiver (Referred as A in
traditional RS485 Transceiver) and L1 is inverting Bus I/O for
transceiver (Referred as B in traditional RS485 Transceiver).
Under Polarity reversal status, L2 become inverting bus I/O and
L1 become non inverting Bus I/O.
Power Supply for RS-485 transceiver
7
8
L1
V
CC
RS-485 Communication Function Table
Table1. Transmitting
INPUTS
______
DE
RE
X
H
X
H
L
L/O
H
L/O
Table2. Receiving
INPUTS
______
OUTPUTS
DI
H/O
L
X
X
A
H
L
Z
Shutdown
B
L
H
Z
RE
L
L
L
H
H
DE
X
X
X
H
L
V
ID
=V
A
-V
B
≥-50mV
≤-200mV
Open/Shorted
X
X
OUTPUTS
RO
H
L
H
Z
Shutdown
H: High, L: Low, X: Do not care, Z: High impedance.
V
A
: Input Voltage of RS485 Non Inverting Bus I/O terminal,
V
B
: Input Voltage of RS485 Inverting Bus I/O terminal.
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