19-2320; Rev 0; 1/02
±15kV ESD-Protected 52Mbps, 3V to 5.5V, SOT23
RS-485/RS-422 True Fail-Safe Receivers
General Description
The MAX3280E/MAX3281E/MAX3283E/MAX3284E are
single receivers designed for RS-485 and RS-422 com-
munication. These devices guarantee data rates up to
52Mbps, even with a 3V power supply. Excellent propa-
gation delay (15ns max) and package-to-package
skew time (8ns max) make these devices ideal for mul-
tidrop clock distribution applications.
The MAX3280E/MAX3281E/MAX3283E/MAX3284E
have true fail-safe circuitry, which guarantees a logic-
high receiver output when the receiver inputs are
opened or shorted. The receiver output will be a logic
high if all transmitters on a terminated bus are disabled
(high impedance). These devices feature 1/4-unit-load
receiver input impedance, allowing up to 128 receivers
on the same bus.
The MAX3280E is a single receiver available in a 5-pin
SOT23 package. The MAX3281E/MAX3283E single
receivers have a receiver enable (EN or
EN)
function
and are offered in a 6-pin SOT23 package. The
MAX3284E features a voltage logic pin that allows com-
patibility with low-voltage logic levels, as in digital
FPGAs/ASICs. On the MAX3284E, the voltage threshold
for a logic high is user-defined by setting V
L
in the
range from 1.65V to V
CC
. The MAX3284E is also
offered in a 6-pin SOT23 package.
Features
o
ESD Protection:
±15kV–Human Body Model
±6kV–IEC 1000-4-2, Contact Discharge
±12kV–IEC 1000-4-2, Air-Gap Discharge
o
Guaranteed 52Mbps Data Rate
o
Guaranteed 15ns Receiver Propagation Delay
o
Guaranteed 2ns Receiver Skew
o
Guaranteed 8ns Package-to-Package Skew Time
o
V
L
Pin for Connection to FPGAs/ASICs
o
Allow Up to 128 Transceivers on the Bus
(1/4-unit-load)
o
Tiny SOT23 Package
o
True Fail-Safe Receiver
o
-7V to +12V Common-Mode Range
o
3V to 5.5V Power-Supply Range
o
Enable (High and Low) Pins for Redundant
Operation
o
Three-State Output Stage (MAX3281E/MAX3283E)
o
Thermal Protection Against Output Short Circuit
MAX3280E/MAX3281E/MAX3283E/MAX3284E
Applications
Clock Distribution
Telecom Racks
Base Stations
Industrial Control
Local Area Networks
Pin Configurations appear at end of data sheet.
PART
MAX3280EAUK-T
MAX3281EAUT-T
MAX3283EAUT-T
MAX3284EAUT-T
Ordering Information
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-
PACKAGE
5 SOT23-5
6 SOT23-6
6 SOT23-6
6 SOT23-6
TOP
MARK
ADVM
ABAT
ABAU
ABAV
Selector Guide
PART
MAX3280E
MAX3281E
MAX3283E
MAX3284E
V
L
—
—
—
✔
ENABLE
—
Active High
Active Low
—
DATA RATE
52Mbps
52Mbps
52Mbps
52Mbps (Note 1)
PACKAGE
5-Pin SOT23
6-Pin SOT23
6-Pin SOT23
6-Pin SOT23
Note 1:
MAX3284E data rate is dependent on V
L
.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
±15kV ESD-Protected 52Mbps, 3V to 5.5V, SOT23
RS-485/RS-422 True Fail-Safe Receivers
MAX3280E/MAX3281E/MAX3283E/MAX3284E
ABSOLUTE MAXIMUM RATINGS
(All Voltages Referenced to GND)
Supply Voltage (V
CC
) ...............................................-0.3V to +6V
Control Input Voltage (EN,
EN).................................-0.3V
to +6V
V
L
Input Voltage .......................................................-0.3V to +6V
Receiver Input Voltage (A, B)..............................-7.5V to +12.5V
Receiver Output Voltage (RO)....................-0.3V to (V
CC
+ 0.3V)
Receiver Output Voltage
(RO) (MAX3284E) .....................................-0.3V to (V
L
+ 0.3V)
Receiver Output Short-Circuit Current .......................Continuous
Continuous Power Dissipation (T
A
= +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C)............571mW
6-Pin SOT23 (derate 8.7mW/°C above +70°C)............696mW
Operating Temperature Range
MAX328_EA__ ..............................................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+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.
ELECTRICAL CHARACTERISTICS
(V
CC
= 3V to 5.5V, V
L
= V
CC
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= 5V and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
Supply Voltage
Supply Current
V
L
Input Range
V
L
Supply Current
RECEIVER
Input Current (A and B)
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Receiver Enable Input Low
Receiver Enable Input High
Receiver Enable Input Leakage
I
A, B
V
TH
∆V
TH
V
ENIL
V
ENIH
I
LEAK
V
CC
= GND or 5.5V
-7V
≤
V
CM
≤
+12V
(Note 4)
V
A
+ V
B
= 0
MAX3281E, MAX3283E only
MAX3281E, MAX3283E only
MAX3281E, MAX3283E only
MAX3280E/MAX3281E/MAX3283E,
I
OH
= -4mA, RO high
MAX3284E, I
OH
= -1mA, 1.65V
≤
V
L
≤
V
CC
,
RO high
MAX3280E/MAX3281E/MAX3283E,
I
OL
= 4mA, RO low
MAX3284E, I
OL
= 1mA, 1.65V
≤
V
L
≤
V
CC
,
RO low
0
≤
V
O
≤
V
CC
, RO = high impedance
-7V
≤
V
CM
≤
+12V (Note 5)
0
≤
V
RO
≤
V
CC
48
±130
V
CC
- 0.4
V
V
L
- 0.4
0.4
V
0.4
±5
µA
kΩ
mA
2
±10
V
IN
= +12V
V
IN
= -7V
-200
-125
25
0.4
250
-200
-50
µA
mV
mV
V
V
µA
SYMBOL
V
CC
I
CC
V
L
I
L
No load
MAX3284E
No load (MAX3284E)
1.65
CONDITIONS
MIN
3.0
9
TYP
MAX
5.5
15
V
CC
10
UNITS
V
mA
V
µA
Receiver Output High Voltage
V
OH
Receiver Output Low Voltage
V
OL
Three-State Output Current at
Receiver
Receiver Input Resistance
Receiver Output Short-Circuit
Current
ESD PROTECTION
I
OZR
R
IN
I
OSR
Human Body Model
ESD Protection (A, B)
IEC1000-4-2 (Air-Gap Discharge)
IEC1000-4-2 (Contact Discharge)
±15
±12
±6
kV
2
_______________________________________________________________________________________
±15kV ESD-Protected 52Mbps, 3V to 5.5V, SOT23
RS-485/RS-422 True Fail-Safe Receivers
SWITCHING CHARACTERISTICS
(V
CC
= 3V to 5.5V, V
L
= V
CC
, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= 5V and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
Maximum Data Rate
Receiver Propagation Delay
Receiver Output |t
PLH
- t
PHL
|
Device-to-Device Propagation
Delay Matching
SYMBOL
f
MAX
t
PLH
t
PHL
t
PSKEW
CONDITIONS
C
L
= 15pF (Notes 5, 6)
Figure 1, C
L
= 15pF, V
ID
= 2V, V
CM
= 0
Figure 1, C
L
= 15pF, V
ID
= 2V, V
CM
= 0
Figure 1, C
L
= 15pF, T
A
= +25°C
Same power supply, maximum temperature
difference between devices = +30°C.
(Note 5)
MIN
52
7
8
15
15
2
8
TYP
MAX
UNITS
Mbps
ns
ns
ns
MAX3280E/MAX3281E/MAX3283E/MAX3284E
ENABLE/DISABLE TIME FOR MAX3281E/MAX3283E
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
t
PRZL
t
PRZH
t
PRLZ
t
PRHZ
Figure 2, C
L
= 15pF
Figure 2, C
L
= 15pF
Figure 2, C
L
= 15pF
Figure 2, C
L
= 15pF
500
500
500
500
ns
ns
ns
ns
Note 2:
Parameters are 100% production tested at +25°C, limits over temperature are guaranteed by design.
Note 3:
All currents into the device are positive; all currents out of the device are negative. All voltages are referenced to device
ground, unless otherwise noted.
Note 4:
V
CM
is the common-mode input voltage. V
ID
is the differential input voltage.
Note 5:
Not production tested. Guaranteed by design.
Note 6:
See Table 2 for MAX3284E data rates with V
L
< V
CC
.
Typical Operating Characteristics
(V
CC
= 3.3V, T
A
= +25°C, unless otherwise noted.)
RECEIVER OUTPUT LOW VOLTAGE
vs. OUTPUT CURRENT
MAX3280/1/3/4E toc01
RECEIVER OUTPUT HIGH VOLTAGE
vs. OUTPUT CURRENT
MAX3280/1/3/4E toc02
RECEIVER OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
RECEIVER OUTPUT HIGH VOLTAGE (V)
V
CC
= 5V
4.5
MAX3280/1/3/4E toc03
5
5
5.0
4
OUTPUT VOLTAGE (V)
4
OUTPUT VOLTAGE (V)
V
CC
= 5V
3
V
CC
= 3.3V
2
3
V
CC
= 3.3V
V
CC
= 5V
4.0
2
3.5
V
CC
= 3.3V
3.0
A = 1V, B = GND, I
OH
= -4mA
-50
-25
0
25
50
75
100
125
1
1
0
0
10
20
30
40
50
60
OUTPUT CURRENT (mA)
0
-50
-40
-30
-20
-10
0
OUTPUT CURRENT (mA)
2.5
TEMPERATURE (°C)
_______________________________________________________________________________________
3
±15kV ESD-Protected 52Mbps, 3V to 5.5V, SOT23
RS-485/RS-422 True Fail-Safe Receivers
MAX3280E/MAX3281E/MAX3283E/MAX3284E
Typical Operating Characteristics (continued)
(V
CC
= 3.3V, T
A
= +25°C, unless otherwise noted.)
RECEIVER OUTPUT LOW VOLTAGE
vs. TEMPERATURE
MAX3280/1/3/4E toc04
RECEIVER PROPAGATION DELAY (t
PLH
)
vs. TEMPERATURE
MAX3280/1/3/4E toc05
RECEIVER PROPAGATION DELAY (t
PHL
)
vs. TEMPERATURE
MAX3280/1/3/4E toc06
200
RECEIVER OUTPUT LOW VOLTAGE (mV)
9
10
150
V
CC
= 3.3V
100
V
CC
= 5V
8
V
CC
= 5V
t
PLH
(ns)
9
t
PHL
(ns)
V
CC
= 5V
8
V
CC
= 3.3V
7
7
V
CC
= 3.3V
6
50
5
A = GND, B = 1V, I
OL
= 4mA
0
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
4
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
6
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
SUPPLY CURRENT vs. TEMPERATURE
MAX3280/1/3/4E toc07
MAX3284E MAXIMUM DATA RATE
vs. VOLTAGE LOGIC LEVEL
MAX3280/1/3/4E toc08
9
V
CC
= 5V
SUPPLY CURRENT (mA)
8
60
50
DATA RATE (Mbps)
7
40
6
V
CC
= 3.3V
5
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
30
20
1.5
2.5
3.5
4.5
5.5
VOLTAGE LOGIC LEVEL (V)
SUPPLY CURRENT vs. DATA RATE
MAX3280/1/3/4E toc09
V
L
SUPPLY CURRENT
vs. TEMPERATURE
MAX3280/1/3/4 toc10
10
I
CC
, V
CC
= V
L
= 5V
8
SUPPLY CURRENT (mA)
I
CC
, V
CC
= V
L
= 3.3V
I
L
, V
CC
= V
L
= 5V
4
10
V
L
SUPPLY CURRENT (mA)
1
6
V
CC
= V
L
= 5V
DATA RATE = 52Mbps V
CC
= V
L
= 3.3V
DATA RATE = 52Mbps
0.1
V
CC
= V
L
= 5V
DATA RATE = 100kbps
0.01
V
CC
= V
L
= 3.3V
DATA RATE = 100kbps
2
I
L
, V
CC
= V
L
= 3.3V
0
10
100
1000
DATA RATE (kbps)
10,000
100,000
0.001
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
4
_______________________________________________________________________________________
±15kV ESD-Protected 52Mbps, 3V to 5.5V, SOT23
RS-485/RS-422 True Fail-Safe Receivers
Pin Description
PIN
MAX3280E
1
2
3
4
—
—
MAX3281E
1
2
3
4
—
5
MAX3283E
1
2
3
4
5
—
MAX3284E
1
2
3
4
—
—
NAME
V
CC
GND
RO
B
EN
EN
FUNCTION
Positive Supply: 3V
≤
V
CC
≤
5.5V. Bypass with a 0.1µF
capacitor to GND.
Ground
Receiver Output. RO will be high if (A–B)
≥
-50mV. RO will be
low if (A–B)
≤
-200mV.
Inverting Receiver Input
Receiver Output Enable. Drive
EN
low to enable RO. When
EN
is high, RO is high impedance.
Receiver Output Enable. Drive EN high to enable RO. When
EN is low, RO is high impedance.
Low-Voltage Logic-Level Supply Voltage. V
L
is a user-defined
voltage, ranging from 1.65V to V
CC
. RO output high is pulled up
to V
L
. Bypass with a 0.1µF capacitor to GND.
Noninverting Receiver Input
MAX3280E/MAX3281E/MAX3283E/MAX3284E
—
5
—
6
—
6
5
6
V
L
A
Detailed Description
The MAX3280E/MAX3281E/MAX3283E/MAX3284E are
single, true fail-safe receivers designed to operate at
data rates up to 52Mbps. The fail-safe architecture guar-
antees a high output signal if both input terminals are
open or shorted together. See the
True Fail-Safe
section.
This feature assures a stable and predictable output
logic state with any transmitter driving the line. These
receivers function with a 3.3V or 5V supply voltage and
feature excellent propagation delay times (15ns).
The MAX3280E is a single receiver available in a 5-pin
SOT23 package. The MAX3281E (EN, active high) and
MAX3283E (EN, active low) are single receivers that
also contain an enable pin. Both the MAX3281E and
MAX3283E are available in a 6-pin SOT23 package.
The MAX3284E is a single receiver that contains a V
L
pin, which allows communication with low-level logic
included in digital FPGAs. The MAX3284E is available
in a 6-pin SOT23 package.
The MAX3284E’s low-level logic application allows
users to set the logic levels. A logic high level of 1.65V
will limit the maximum data rate to 20Mbps.
±15kV ESD without damage. After an ESD event, this
family of parts continues working without latchup.
ESD protection can be tested in several ways. The
receiver inputs are characterized for protection to the
following:
• ±15kV using the Human Body Model
• ±6kV using the Contact Discharge method specified
in IEC 1000-4-2 (formerly IEC 801-2)
• ±12kV using the Air-Gap Discharge method speci-
fied in IEC 1000-4-2 (formerly IEC 801-2)
ESD Test Conditions
ESD performance depends on a number of conditions.
Contact Maxim for a reliability report that documents
test setup, methodology, and results.
Human Body Model
Figure 3a shows the Human Body Model, and Figure
3b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter-
est, which is then discharged into the device through a
1.5kΩ resistor.
±15kV ESD Protection
ESD-protection structures are incorporated on the
receiver input pins to protect against ESD encountered
during handling and assembly. The MAX3280E/
MAX3281E/MAX3283E/MAX3284E receiver inputs (A,
B) have extra protection against static electricity found
in normal operation. Maxim’s engineers developed
state-of-the-art structures to protect these pins against
IEC 1000-4-2
Since January 1996, all equipment manufactured
and/or sold in the European community has been
required to meet the stringent IEC 1000-4-2 specifica-
tion. The IEC 1000-4-2 standard covers ESD testing
and performance of finished equipment; it does not
specifically refer to integrated circuits. The
MAX3280E/MAX3281E/MAX3283E/MAX3284E help
5
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