19-2770; Rev 3; 3/11
20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
General Description
The MAX3293/MAX3294/MAX3295 low-power, high-
speed transmitters for RS-485/RS-422 communication
operate from a single +3.3V power supply. These
devices contain one differential transmitter. The
MAX3295 transmitter operates at data rates up to
20Mbps, with an output skew of less than 5ns, and a
guaranteed driver propagation delay below 25ns. The
MAX3293 (250kbps) and MAX3294 (2.5Mbps) are
slew-rate limited to minimize EMI and reduce reflections
caused by improperly terminated cables.
The MAX3293/MAX3294/MAX3295 output level is guar-
anteed at +1.5V with a standard 54Ω load, compliant
with RS-485 specifications. The transmitter draws 5mA
of supply current when unloaded, and 1µA in low-
power shutdown mode (DE = GND).
Hot-swap circuitry eliminates false transitions on the data
cable during circuit initialization or connection to a live
backplane, and short-circuit current limiting and thermal-
shutdown circuitry protect the driver against excessive
power dissipation.
The MAX3293/MAX3294/MAX3295 are offered in a
6-pin SOT23 package, and are specified over the
automotive temperature range.
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
Features
Space-Saving 6-Pin SOT23 Package
250kbps/2.5Mbps/20Mbps Data Rates Available
Operate from a Single +3.3V Supply
ESD Protection
±9kV—Human Body Model
Slew-Rate Limited for Errorless Data
Transmission (MAX3293/MAX3294)
1µA Low-Current Shutdown Mode
-7V to +12V Common-Mode Input Voltage Range
Current Limiting and Thermal Shutdown for
Driver-Overload Protection
Hot-Swap Inputs for Telecom Applications
Automotive Temperature Range (-40°C to +125°C)
MAX3293/MAX3294/MAX3295
Ordering Information
PART
MAX3293AUT+T
MAX3294AUT+T
MAX3295AUT+T
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
6 SOT23-6
6 SOT23-6
6 SOT23-6
Applications
RS-485/RS-422 Communications
Clock Distribution
Telecom Equipment
Automotive
Security Equipment
Point-of-Sale Equipment
Industrial Control
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Selector Guide
PART
MAXIMUM
DATA RATE
(Mbps)
0.25
2.5
20
SLEW-
RATE
LIMITED
Yes
Yes
No
TOP
MARK
ABNI or
ABVH
ABNJ or
ABVI
ABNK or
ABVJ
MAX3293AUT+T
MAX3294AUT+T
MAX3295AUT+T
Typical Operating Circuit
120Ω
DI
DE
Z
D
Y
R
RO
Pin Configuration appears at end of data sheet.
MAX3293
MAX3294
MAX3295
MAX3280E
MAX3281E
MAX3283E
MAX3284E
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
MAX3293/MAX3294/MAX3295
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.)
Supply Voltage (V
CC
).............................................................+6V
DE, DI .......................................................................-0.3V to +6V
Y, Z .........................................................................-7V to +12.5V
Maximum Continuous Power Dissipation (T
A
= +70°C)
SOT23 (derate 8.2mW/°C above +70°C) .................654.1mW
Operating Temperature Ranges
MAX32_ _AUT...............................................-40°C to +125°C
Storage Temperature Range .............................-65°C to +160°C
Junction Temperature .....................................................+160°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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
= +3.3V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (Notes 1, 2)
PARAMETER
POWER SUPPLY
Supply Voltage
Supply Current in Normal
Operation
Supply Current in Shutdown Mode
DRIVER
Figure 1, DE = V
CC
,
DI = GND or V
CC
R = 50Ω (RS-422),
T
A
≤
+85°C
R = 27Ω (RS-485),
T
A
≤
+85°C
2.0
1.5
V
CC
V
V
CC
0.2
-1
+3
0.2
V
V
V
V
CC
I
Q
I
SHDN
No load, DI = V
CC
or GND, DE = V
CC
No load, DE = GND
1
3.135
3.300
3.465
5
10
V
mA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Differential Driver Output
V
OD
Change in Magnitude of
Differential Output Voltage
Driver Common-Mode Output
Voltage
Change in Magnitude of Common-
Mode Voltage
DRIVER LOGIC
Input High Voltage
Input Low Voltage
Input Current
ΔV
OD
V
OC
ΔV
OC
Figure 1, R = 27Ω or 50Ω,
DE = V
CC
(Note 3)
Figure 1, R = 27Ω or 50Ω,
DE = V
CC
, DI = V
CC
or GND
Figure 1, R = 27Ω or 50Ω (Note 3)
V
IH
V
IL
I
IN
DE, DI
DE, DI
DE, DI
Y, Z
DE = GND,
V
CC
= GND or
+3.3V
V
IN
= +12V
V
IN
= -7V
2.0
0.8
-2
-20
-20
+25
-25
-250
+250
160
40
+2
+20
V
V
µA
Output Leakage
I
O
µA
+20
mA
mA
°C
°C
kV
Driver Short-Circuit Foldback
Output Current
Driver Short-Circuit
Output Current
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
ESD Protection
I
OSFD
I
OSD
T
TS
T
TSH
(V
CC
- 1V)
≤
V
OUT
≤
+12V, output high
-7V
≤
V
OUT
≤
1V, output high
0
≤
V
OUT
≤
+12V, output low
-7V
≤
V
OUT
≤
V
CC
, output high
Y, Z
Human Body Model
±9
2
_______________________________________________________________________________________
20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
SWITCHING CHARACTERISTICS (MAX3293)
(V
CC
= +3.3V ±5%, T
A
= +25°C, unless otherwise noted. Typical values are at V
CC
= +3.3V.)
PARAMETER
Driver Propagation Delay
Driver Differential Output Rise
or Fall Time
Driver-Output Skew
Differential Driver-Output Skew
Maximum Data Rate
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Device-to-Device Propagation
Delay Matching
t
ZH
t
ZL
t
LZ
t
HZ
SYMBOL
t
PLH
t
PHL
t
R
t
F
t
SKEW
t
DSKEW
CONDITIONS
Figures 2, 3; R
DIFF
= 54 ,
C
L
= 50pF
Figures 2, 3; R
DIFF
= 54 ,
C
L
= 50pF
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF,
t
SKEW
= | t
PLH
- t
PHL
| (Note 5)
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF
Figures 4, 5; S2 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S1 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S1 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S2 closed, R
L
= 500 ,
C
L
= 100pF
Same power supply, maximum temperature
difference between devices = +30°C (Note 5)
MIN
400
400
400
400
-400
-100
250
2000
2000
1000
1000
900
TYP
MAX
1300
1300
1200
1200
+400
+100
UNITS
ns
ns
ns
ns
kbps
ns
ns
ns
ns
ns
MAX3293/MAX3294/MAX3295
SWITCHING CHARACTERISTICS (MAX3294)
(V
CC
= +3.3V ±5%, T
A
= +25°C, unless otherwise noted. Typical values are at V
CC
= +3.3V.)
PARAMETER
Driver Propagation Delay
Driver Differential Output Rise
or Fall Time
Driver-Output Skew
Differential Driver-Output Skew
Maximum Data Rate
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Device-to-Device Propagation
Delay Matching
t
ZH
t
ZL
t
LZ
t
HZ
SYMBOL
t
PLH
t
PHL
t
R
t
F
t
SKEW
t
DSKEW
CONDITIONS
Figures 2, 3; R
DIFF
= 54 ,
C
L
= 50pF
Figures 2, 3; R
DIFF
= 54 ,
C
L
= 50pF
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF,
t
SKEW
= | t
PLH
- t
PHL
| (Note 5)
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF
Figures 4, 5; S2 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S1 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S1 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S2 closed, R
L
= 500 ,
C
L
= 100pF
Same power supply, maximum temperature
difference between devices = +30°C (Note 5)
MIN
24
24
10
10
-40
-6
2.5
400
400
100
100
46
TYP
MAX
70
70
70
70
+40
+6
UNITS
ns
ns
ns
ns
Mbps
ns
ns
ns
ns
ns
_______________________________________________________________________________________
3
20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
MAX3293/MAX3294/MAX3295
SWITCHING CHARACTERISTICS (MAX3295)
(V
CC
= +3.3V ±5%, T
A
= +25°C, unless otherwise noted. Typical values are at V
CC
= +3.3V.)
PARAMETER
Driver Propagation Delay
SYMBOL
t
PLH
t
PHL
t
R
t
F
Driver-Output Skew
Differential Driver-Output Skew
Maximum Data Rate
t
SKEW
t
DSKEW
CONDITIONS
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF
T
A
= -40°C to +125°C
Figures 2, 3;
R
DIFF
= 54 ,
C
L
= 50pF
T
A
< +85°C
T
A
= -40°C to +125°C
T
A
< +85°C
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF,
t
SKEW
= | t
PLH
- t
PHL
|
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF,
T
A
+85°C
Figures 2, 3; R
DIFF
= 54 , C
L
= 50pF
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Device-to-Device Propagation
Delay Matching
t
ZH
t
ZL
t
LZ
t
HZ
Figures 4, 5; S2 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S1 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S1 closed, R
L
= 500 ,
C
L
= 100pF
Figures 4, 5; S2 closed, R
L
= 500 ,
C
L
= 100pF
Same power supply, maximum temperature
difference between devices = +30°C (Note 5)
20
16
400
400
100
100
25
ns
ns
ns
ns
ns
5
5
MIN
TYP
MAX
25
25
18.5
15
18.5
15
ns
ns
Mbps
ns
UNITS
ns
Driver Differential Output Rise
or Fall Time
Note 1:
Devices production tested at +25°C. Limits over the operating temperature range are guaranteed by design.
Note 2:
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 3:
ΔV
OD
and
ΔV
OC
are the changes in V
OD
and V
OC
, respectively, when the DI input changes state.
Note 4:
The maximum current applies to peak current just prior to foldback current limiting.
Note 5:
Guaranteed by design; not production tested.
4
_______________________________________________________________________________________
20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
Test Circuits and Timing Diagrams
Y
R
V
OD
R
Z
V
OC
OUTPUT
UNDER TEST
C
L
S2
R
L
S1
V
CC
MAX3293/MAX3294/MAX3295
Figure 1. Driver DC Test Load
Figure 4. Enable/Disable Timing Test Load
3V
3V
DE
0V
1.5V
1.5V
DE
DI
Y
V
ID
Z
R
DIFF
C
L
t
ZL(SHDN)
, t
ZL
Y, Z
V
OL
t
LZ
V
OL
+ 0.25V
2.3V OUTPUT NORMALLY LOW
C
L
Y, Z
2.3V
0V
OUTPUT NORMALLY HIGH
V
OH
- 0.25V
t
HZ
t
ZH(SHDN)
, t
ZH
Figure 2. Driver Timing Test Circuit
Figure 5. Driver Enable and Disable Times
3V
DI
0V
1.5V
f = 1MHz, t
R
≤
3ns, t
F
≤
3ns
1.5V
t
PLH
t
PHL
1/2 V
O
Z
V
O
Y
1/2 V
O
V
O
V
DIFF
0V
-V
O
V
DIFF
= V (Y) - V (Z)
90%
10%
t
R
t
F
t
SKEW
= | t
PLH
- t
PHL
|
90%
10%
Figure 3. Driver Propagation Delays
_______________________________________________________________________________________
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