GM3485E
±
15kV ESD-Protected ,Fail-Safe,High-Speed(10Mbps)
Slew-Rate-Limited RS-485 Transceivers
General Description
The GM3485E is +/- 15kV electrostatic
discharge (ESD) protected, high-speed
transceiver for RS-485 communication that
contain one driver and one receiver. The device
features fail-safe circuitry, which guarantees a
logic-high receiver output when the receiver
inputs are open or shorted. This means that the
receiver output will be logic-high even if all
transmitters on a terminated bus are disabled.
The GM3485E driver slew rate is not limited,
making transmit speeds up to 10Mbps possible.
All transmitter outputs and receiver inputs are
protected to +/- 15kV using the Human Body
Model. The transceiver typically draws 500
micron ampere of supply current when
unloaded, or when fully loaded with the driver
disabled. This device has a 1-unit-load receiver
input impedance that allows up to 32
transceivers on the bus. The GM3485E is
intended for half-duplex communications.
I/O ESD protection
Human Body Model: ±15kV
IEC 61000-4-2：
Contact discharge: ±12kV
Air discharge: ±15kV
Features
True Fail-Safe Receiver While Maintaining
EIA/TIA-485 Compatibility
Low Quiescent Supply Current: 500uA
Allow Up to 32 Transceivers on the Bus
1nA Low-Current Shutdown Mode
Applications
RS-485 Communications
Level Translators
Motor Controller
Industrial Control Local Area Networks
Energy Meter Networks
Power Inverters
Building Automation Networks
Telecommunications Equipment
PIN Configuration
GM3485E Pin figure
Ordering Information
PART
GM3485E
Duplex
Half
Data
Rate
10Mbps
Supply
Voltage
3.3V
Low- Power
Shutdown
YES
Rx/Tx
on Bus
32
IEC 61000-4-2
Air discharge
±15kV
TEMP
RANGE
-40℃½+85℃
PIN
PACKAGE
8 SOP
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Hang Zhou Gatemode Microelectronics Ltd
-1-
GM3485E
Pin Description
PIN
1
2
3
NAME
RO
RE
FUNCTION
Receiver Output. When RE is low and if A - B ≥
-200mV, RO will be low.
Receiver Output Enable. Drive
high. Drive
RE
RE
-50mV, RO will be high; if A- B ≤
RE
low to enable RO; RO is high impedance when
is
high and DE low to enter low-power shutdown mode.
RE
DE
Driver Output Enable. Drive DE high to enable driver outputs. These outputs are high
impedance when DE is low. Drive
high and DE low to enter low-power shutdown mode.
Driver Input. With DE high, a low on DI forces non-inverting output low and inverting
4
5
6
7
8
DI
GND
A
B
VCC
output high. Similarly, a high on DI forces non-inverting output high and inverting output
low.
Ground
Non-inverting Receiver Input and Non-inverting Driver Output.
Inverting Receiver Input and Inverting Driver Output.
Positive Supply 3.0V ≤ VCC ≤
3.6V.
ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply Voltage (VCC)
Control Input Voltage (
R E
, DE)
Driver Input Voltage (DI)
Driver Output Voltage (A, B)
Receiver Input Voltage (A, B)
Receiver Output Voltage (RO)
Continuous Power Dissipation
Operating Temperature Ranges
Storage Temperature Range
Lead Temperature (soldering, 10s)
SYMBOL
V
CC
RE
NUM
+6.0
-0.3 to V
CC
+0.3
-0.3 toV
CC
+0.3
±13
±13
-0.3½V
CC
+0.3
471
-40½+85
-65½+150
300
UNITS
V
V
V
V
V
V
mW
℃
℃
℃
, DE
DI
A, B
A, B
RO
SOP8
DC ELECTRICAL CHARACTERISTICS
PARAMETER
SYMBOL
(VCC = +3.3V ± 5%, TA = T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25°C.)
CONDITIONS
MIN
TYP
MAX
(Note 1)
UNITS
DRIVER
Differential Driver Output
(No Load)
Differential Driver Output
Change-in-Magnitude of
Differential Output Voltage
(Note 2)
Driver Common-Mode
Output Voltage
V
OC
Figure 1, R = 27
1
3
V
V
OD
Figure 1, R = 27
0.2
V
V
OD1
V
OD2
Figure 1
Figure 1, R = 27
2.0
1.5
V
V
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Hang Zhou Gatemode Microelectronics Ltd
-2-
GM3485E
Change-in-Magnitude of
Common-Mode Voltage
(Note 2)
Input High Voltage
Input Low Voltage
DI Input Hysteresis
Input Current (A and B)
V
IH1
V
IL1
V
HYS
I
IN1
DE = GND, VCC =
GND or 3.3V
-7V
≦V
OUT
≦VCC
Driver Short-Circuit
Output Current
(Note 3)
I
OSD
0V
≦V
OUT
≦12V
0V
≦V
OUT
≦VCC
±25
V
IN
= 12V
V
IN
= -7V
-500
-250
250
mA
DE, DI,
DE, DI,
RE
V
OC
Figure 1, R = 27
0.2
V
2.0
0.8
100
500
V
V
mV
µA
RE
RECEIVER
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State Output Current at
Receiver
Receiver Input Resistance
Receiver Output Short-Circuit
Current
V
TH
V
TH
V
OH
V
OL
I
OZR
R
IN
I
OSR
I
O
= -4mA, V
ID
= -50mV
I
O
= 4mA, V
ID
= -200mV
0.4V
≦V
O
≦2.4V
-7V≦V
CM
≦12V
0V
≦V
RO
≦VCC
12
±7
±95
V
CC
-
0.4
0.4
±1
-7V
≦V
CM
≦12V
-200
-110
30
-50
mV
mV
V
V
µA
kΩ
mA
SUPPLY CURRENT
Supply Current
Supply Current in Shutdown
Mode
ESD Protection for
A, B
I
CC
I
SHDN
No load,
RE
=
DE = VCC
DE = GND
500
400
0.001
±15
900
600
1
µA
µA
µA
kV
DI= GND or VCC
DE = GND, V
R E
= VCC
Human Body Model
SWITCHING CHARACTERISTICS
PARAMETER
Driver Input to Output
SYMBOL
t
DPLH
t
DPHL
t
DSKEW
t
DR
, t
DF
(VCC = +3.3V ± 5%, TA = T
MIN
to T
MAX
, unless otherwise noted. Typical values are at VCC = +3.3V and T
A
= +25°C.)
CONDITIONS
Figure 3 and 5, R
DIFF
=54,
C
L1
= C
L2
=100pF
Figure 3 and 5, R
DIFF
=54,
C
L1
= C
L2
=100pF
Figure 3 and 5, R
DIFF
=54,
C
L1
= C
L2
=100pF
MIN
TYP
20
20
-3
12
MAX
40
40
±10
25
UNITS
ns
Driver Output Skew | t
DPLH
– t
DPHL
|
Driver Rise or Fall Time
ns
ns
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Hang Zhou Gatemode Microelectronics Ltd
-3-
GM3485E
Maximum Data Rate
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Receiver Input to Output
| t
RPLH
– t
RPHL
| Differential Receiver
Skew
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
f
MAX
t
DZH
t
DZL
t
DLZ
t
DHZ
t
RPLH,
t
RPHL
t
RSKD
t
RZL
t
RHZ
t
RLZ
t
RHZ
t
SHDN
t
DZH(SHDN)
t
DZL(SHDN)
t
RZH(SHDN)
t
RZL(SHDN)
Figure 4and 6, C
L
=100pF, S2 closed
Figure 4and 6, C
L
=100pF, S1 closed
Figure 4and 6, C
L
= 15pF,
S1 closed
Figure 4and 6, C
L
= 15pF,S2 closed
Figure 9, | V
ID
|≧2.0V rise and fall
time of V
ID
≦15ns
Figure 9, | V
ID
|≧2.0V rise and fall
time of V
ID
≦15ns
Figure 2, C
L
=100pF, S1 closed
Figure 2, C
L
=100pF, S2 closed
Figure 2, C
L
=100pF, S1 closed
Figure 2, C
L
=100pF, S2 closed
(Note 4)
Figure 4, C
L
= 15pF,S2 closed
Figure 4, C
L
= 15pF,S1 closed
Figure 2, C
L
=100pF,S2 closed
Figure 2, C
L
=100pF,S1 closed
50
50
0
20
20
20
20
200
±10
50
50
50
50
600
250
250
3500
3500
10
150
150
100
100
Mbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
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.
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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Hang Zhou Gatemode Microelectronics Ltd
-4-
GM3485E
Typical Operating Characteristics
(VCC = +3.3V, TA = +25°C, unless otherwise noted.)
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Hang Zhou Gatemode Microelectronics Ltd
-5-
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