MAX3293-95 Datasheet by Maxim Integrated

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General Description
The MAX3293/MAX3294/MAX3295 low-power, high-
speed transmitters for RS-485/RS-422 commu-
nication 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
guaranteed at +1.5V with a standard 54 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.
Applications
RS-485/RS-422 Communications
Clock Distribution
Telecom Equipment
Automotive
Security Equipment
Point-of-Sale Equipment
Industrial Control
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)
AEC-Q100 Qualified MAX3295AUT/V+T
19-2770; Rev 5; 4/19
Pin Configuration appears at end of data sheet.
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
/V denotes automotive-qualified package.
PART
MAXIMUM
DATA RATE
(Mbps)
SLEW-
RATE
LIMITED
TOP
MARK
MAX3293AUT+T 0.25 Yes ABNI or
ABVH
MAX3294AUT+T 2.5 Yes ABNJ or
ABVI
MAX3295AUT+T 20 No ABNK or
ABVJ
MAX3295AUT/V+T 20 No +ACSB
PART TEMP RANGE PIN-PACKAGE
MAX3293AUT+T -40°C to +125°C 6 SOT23-6
MAX3294AUT+T -40°C to +125°C 6 SOT23-6
MAX3295AUT+T -40°C to +125°C 6 SOT23-6
MAX3295AUT/V+T -40°C to +125°C 6 SOT23-6
MAX3293
MAX3294
MAX3295
D
DI
DE
MAX3280E
MAX3281E
MAX3283E
MAX3284E
RRO
120
Z
Y
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
Selector Guide
Ordering Information
Typical Operating Circuit
Click here for production status of specific part numbers.
6 SOT23
(All voltages referenced to GND, unless otherwise noted.)
Supply Voltage (VCC) ............................................................+6V
DE, DI ......................................................................-0.3V to +6V
Y, Z ........................................................................-7V to +12.5V
Maximum Continuous Power Dissipation (TA = +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
6 SOT23
Package Code U6CN+2
Outline Number 21-0058
Land Pattern Number 90-0175
Thermal Resistance, Single-Layer Board:
Junction to Ambient (θJA) (C/W) 122.3
Junction to Case (θJC) (C/W) 84
Thermal Resistance, Multilayer Board:
Junction to Ambient (θJA) (C/W) 74.6
Junction to Case (θJC) (C/W) 6
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
2
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.
Absolute Maximum Ratings
Package Information
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
(VCC = +3.3V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25°C.) (Notes 1, 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLY
Supply Voltage VCC 3.135 3.300 3.465 V
Supply Current in Normal
Operation IQNo load, DI = VCC or GND, DE = VCC 5 mA
Supply Current in Shutdown Mode ISHDN No load, DE = GND 1 10 µA
DRIVER
Differential Driver Output VOD
Figure 1, DE = VCC,
DI = GND or VCC
R = 50 (RS-422),
TA ≤ +85°C 2.0 VCC
V
R = 27 (RS-485),
TA ≤ +85°C 1.5 VCC
Change in Magnitude of
Differential Output Voltage VOD
Figure 1, R = 27 or 50,
DE = VCC (Note 3) 0.2 V
Driver Common-Mode
Output Voltage VOC
Figure 1, R = 27 or 50,
DE = VCC, DI = VCC or GND -1 +3 V
Change in Magnitude of
Common-Mode Voltage ∆VOC Figure 1, R = 27 or 50 (Note 3) 0.2 V
DRIVER LOGIC
Input High Voltage VIH DE, DI 2.0 V
Input Low Voltage VIL DE, DI 0.8 V
Input Current IIN DE, DI -2 +2 µA
Output Leakage IO
Y, Z
DE = GND,
VCC = GND or
+3.3V
VIN = +12V -20 +20
µA
VIN = -7V -20 +20
Driver Short-Circuit Foldback
Output Current IOSFD
(VCC - 1V) ≤ VOUT ≤ +12V, output high +25 mA
-7V ≤ VOUT ≤ 1V, output high -25
Driver Short-Circuit
Output Current IOSD
0 ≤ VOUT ≤ +12V, output low -250 mA
-7V ≤ VOUT ≤ VCC, output high +250
Thermal-Shutdown Threshold TTS 160 °C
Thermal-Shutdown Hysteresis TTSH 40 °C
ESD Protection Y, Z Human Body Model ±9 kV
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
3
Electrical Characteristics
(VCC = +3.3V ±5%, TA = +25°C, unless otherwise noted. Typical values are at VCC = +3.3V.)
(VCC = +3.3V ±5%, TA = +25°C, unless otherwise noted. Typical values are at VCC = +3.3V.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Driver Propagation Delay tPLH Figures 2, 3; RDIFF = 54,
CL = 50pF
24 70 ns
tPHL 24 70
Driver Differential Output Rise or
Fall Time
tRFigures 2, 3; RDIFF = 54,
CL = 50pF
10 70 ns
tF10 70
Driver-Output Skew tSKEW
Figures 2, 3; RDIFF = 54, CL = 50pF,
tSKEW = | tPLH - tPHL | (Note 5) -40 +40 ns
Differential Driver-Output Skew tDSKEW Figures 2, 3; RDIFF = 54, CL = 50pF -6 +6 ns
Maximum Data Rate Figures 2, 3; RDIFF = 54, CL = 50pF 2.5 Mbps
Driver Enable to Output High tZH
Figures 4, 5; S2 closed, RL = 500,
CL = 100pF 400 ns
Driver Enable to Output Low tZL
Figures 4, 5; S1 closed, RL = 500,
CL = 100pF 400 ns
Driver Disable Time from Low tLZ
Figures 4, 5; S1 closed, RL = 500,
CL = 100pF 100 ns
Driver Disable Time from High tHZ
Figures 4, 5; S2 closed, RL = 500,
CL = 100pF 100 ns
Device-to-Device Propagation
Delay Matching
Same power supply, maximum temperature
difference between devices = +30°C (Note 5) 46 ns
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Driver Propagation Delay tPLH Figures 2, 3; RDIFF = 54,
CL = 50pF
400 1300 ns
tPHL 400 1300
Driver Differential Output Rise
or Fall Time
tRFigures 2, 3; RDIFF = 54,
CL = 50pF
400 1200 ns
tF400 1200
Driver-Output Skew tSKEW
Figures 2, 3; RDIFF = 54, CL = 50pF,
tSKEW = | tPLH - tPHL | (Note 5) -400 +400 ns
Differential Driver-Output Skew tDSKEW Figures 2, 3; RDIFF = 54, CL = 50pF -100 +100 ns
Maximum Data Rate Figures 2, 3; RDIFF = 54, CL = 50pF 250 kbps
Driver Enable to Output High tZH
Figures 4, 5; S2 closed, RL = 500,
CL = 100pF 2000 ns
Driver Enable to Output Low tZL
Figures 4, 5; S1 closed, RL = 500,
CL = 100pF 2000 ns
Driver Disable Time from Low tLZ
Figures 4, 5; S1 closed, RL = 500,
CL = 100pF 1000 ns
Driver Disable Time from High tHZ
Figures 4, 5; S2 closed, RL = 500,
CL = 100pF 1000 ns
Device-to-Device Propagation
Delay Matching
Same power supply, maximum temperature
difference between devices = +30°C (Note 5) 900 ns
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
4
Switching Characteristics (MAX3294)
Switching Characteristics (MAX3293)
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: ∆VOD and ∆VOC are the changes in VOD and VOC, 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.
(VCC = +3.3V ±5%, TA = +25°C, unless otherwise noted. Typical values are at VCC = +3.3V.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Driver Propagation Delay tPLH Figures 2, 3; RDIFF = 54, CL = 50pF
25 ns
tPHL 25
Driver Differential Output Rise
or Fall Time
tRFigures 2, 3;
RDIFF = 54,
CL = 50pF
TA = -40°C to +125°C 18.5
ns
TA < +85°C 15
tF
TA = -40°C to +125°C 18.5
TA < +85°C 15
Driver-Output Skew tSKEW
Figures 2, 3; RDIFF = 54, CL = 50pF,
tSKEW = | tPLH - tPHL | 5 ns
Differential Driver-Output Skew tDSKEW Figures 2, 3; RDIFF = 54, CL = 50pF 5 ns
Maximum Data Rate
Figures 2, 3; RDIFF = 54, CL = 50pF,
TA ≤ +85°C 20 Mbps
Figures 2, 3; RDIFF = 54, CL = 50pF 16
Driver Enable to Output High tZH
Figures 4, 5; S2 closed, RL = 500,
CL = 100pF 400 ns
Driver Enable to Output Low tZL
Figures 4, 5; S1 closed, RL = 500,
CL = 100pF 400 ns
Driver Disable Time from Low tLZ
Figures 4, 5; S1 closed, RL = 500,
CL = 100pF 100 ns
Driver Disable Time from High tHZ
Figures 4, 5; S2 closed, RL = 500,
CL = 100pF 100 ns
Device-to-Device Propagation
Delay Matching
Same power supply, maximum temperature
difference between devices = +30°C (Note 5) 25 ns
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
5
Switching Characteristics (MAX3295)
iiie 4» m i *1 Figure 1. Driver DC TestLoad Figure 4. Enable/Disable Timing Test Load J P Figure 2. Driver Timing Tesi Circuii H H i m Figure 3. Driver Propagation Delays
Figure 5. Driver Enable and Disable Times
Figure 4. Enable/Disable Timing Test Load
Figure 3. Driver Propagation Delays
Figure 2. Driver Timing Test Circuit
Figure 1. Driver DC Test Load
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0V
Y, Z
VOL
Y, Z
0V
1.5V 1.5V
VOL
+ 0.25V
VOH
- 0.25V
2.3V
2.3V
tZL(SHDN), tZL tLZ
tZH(SHDN), tZH tHZ
DE
S1
S2
OUTPUT
UNDER TEST
VCC
CL
RL
DI
3V
0V
Z
Y
VO
0V
-VO
VO
1.5V
1/2 VO
1/2 VO
tPLH
tF
tR
tPHL
10%
90% 90%
1.5V
10%
VDIFF = V (Y) - V (Z)
tSKEW = | tPLH - tPHL |
VDIFF
f = 1MHz, tR 3ns, tF 3ns
DI
DE
3V
Y
VID
CL
CL
RDIFF
Z
Y
Z
VOD
R
RVOC
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
6
Test Circuits and Timing Diagrams
m g ‘m \_ \\‘ Ru r; : mun /\ / \\ : Vcc N0 LOAD DE
(VCC = +3.3V, TA = +25°C, unless otherwise noted.)
0
10
20
30
40
MAX3293-95 toc09
TEMPERATURE (C)
PROPAGATION DELAY (ns)
-40 20 50 80-10 110
DRIVER PROPAGATION DELAY
vs. TEMPERATURE
tPHL
tPLH
RDIFF = 54
CL = 50pF
0
1
2
3
4
OUTPUT SKEW vs. TEMPERATURE
MAX3293-95 toc08
TEMPERATURE (C)
OUTPUT SKEW (ns)
-40 20 50 80-10 110
DRIVER-OUTPUT CURRENT
vs. DRIVER-OUTPUT HIGH VOLTAGE
MAX3293-95 toc07
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
0
-100
-40
-60
-80
-20
-120
-7 -5 -3 -1 1 3 5
20
DRIVER-OUTPUT CURRENT
vs. DRIVER-OUTPUT LOW VOLTAGE
MAX3293-95 toc06
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
20
80
60
40
100
0
0 2 4 6 8 10 12
140
120
1.0
2.0
2.5
3.0
3.5
MAX3293-95 toc05
TEMPERATURE (C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
-40 20 50 80-10 110
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
RDIFF = 54
RDIFF = 100
1.5
0
10
30
20
40
50
OUTPUT CURRENT
vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX3293-95 toc04
DIFFERENTIAL OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
1.75 2.752.25 2.502.00 3.00 3.25 3.50
0
1.6
1.2
0.8
0.4
2.0
MAX3293-95 toc03
TEMPERATURE (C)
SUPPLY CURRENT (µA)
-40 20 50 80-10 110
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
DE = GND
0
0.5
1.0
1.5
2.0
SUPPLY CURRENT vs. TEMPERATURE
MAX3293-95 toc02
TEMPERATURE (C)
SUPPLY CURRENT (mA)
-40 20 50 80-10 110
DE = VCC
NO LOAD
NO SWITCHING
0
5
10
20
15
25
MAX3295
SUPPLY CURRENT vs. DATA RATE
MAX3293-95 toc01
DATA RATE (Mbps)
SUPPLY CURRENT (mA)
0 105 15 20
DE = VCC
NO LOAD
TA = +85C
TA = +125C
TA = +25C
TA = -40C
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
Maxim Integrated
7
www.maximintegrated.com
Typical Operating Characteristics
(VCC = +3.3V, TA = +25°C, unless otherwise noted.)
PIN NAME FUNCTION
1 DI Driver Input. A logic low on DI forces the noninverting output (Y) low and the inverting output (Z) high.
A logic high on DI forces the noninverting output (Y) high and the inverting output (Z) low.
2 VCC Positive Supply. VCC = +3.3V ±5%. Bypass VCC to GND with a 0.1µF capacitor.
3 DE Driver Output Enable. Force DE high to enable driver. Pull DE low to disable the driver. Hot-swap
input, see the Hot-Swap Capability section.
4 Z Inverting RS-485/RS-422 Output
5 GND Ground
6 Y Noninverting RS-485/RS-422 Output
EYE DIAGRAM (fIN = 20Mbps)
MAX3293-95 toc14
10ns/div
Y, Z: 500mV/div
0V
Y, Z
LOADED DRIVER-OUTPUT WAVEFORM
(fIN = 16Mbps)
MAX3293-95 toc13
20ns/div
Y, Z: 500mV/div
0V
Y, Z
UNLOADED DRIVER-OUTPUT
WAVEFORM (fIN = 16Mbps)
MAX3293-95 toc12
20ns/div
Y, Z: 1V/div
0V
Y, Z
ENABLE RESPONSE TIME
MAX3293-95 toc11
40ns/div
DE
0V
0V
Y-Z
Y, Z, DE: 2V/div
DRIVER PROPAGATION DELAY
MAX3293-95 toc10
20ns/div
Y, Z: 1V/div
DI: 2V/div
DI
0V
0V
Y, Z
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
Maxim Integrated
8
www.maximintegrated.com
Pin Description
Typical Operating Characteristics (continued)
% % rm m Figure 6. Simplified Structure Dime Driver Enable Input (DE)
Detailed Description
The MAX3293/MAX3294/MAX3295 are low-power
transmitters for RS-485/RS-422 communication. The
MAX3295 operates at data rates up to 20Mbps, the
MAX3294 up to 2.5Mbps (slew-rate limited), and the
MAX3293 up to 250kbps (slew-rate limited). These
devices are enabled using an active-high driver enable
(DE) input. When disabled, outputs enter a high-imped-
ance state, and the supply current reduces to 1µA.
The MAX3293/MAX3294/MAX3295 have a hot-swap input
structure that prevents disturbance on the differential signal
lines when a circuit board is plugged into a “hot” back-
plane (see the Hot-Swap Capability section). Drivers are
also short-circuit current limited and are protected against
excessive power dissipation by thermal-shutdown circuitry.
Driver
The driver accepts a single-ended, logic-level input
(DI) and translates it to a differential RS-485/RS-422
level output (Y and Z). Driving DE high enables the
driver, while pulling DE low places the driver outputs
(Y and Z) into a high-impedance state (see Table 1).
Low-Power Shutdown
Force DE low to disable the MAX3293/MAX3294/
MAX3295. In shutdown mode, the device consumes a
maximum of 10µA of supply current.
Hot-Swap Capability
Hot-Swap Input
When circuit boards are inserted into a “hot” or pow-
ered backplane, disturbances to the enable can lead
to data errors. Upon initial circuit board insertion, the
processor undergoes its power-up sequence. During
this period, the output drivers are high impedance
and are unable to drive the DE input of the MAX3293/
MAX3294/MAX3295 to a defined logic level. Leakage
currents up to 10µA from the high-impedance out-
put could cause DE to drift to an incorrect logic state.
Additionally, parasitic circuit board capacitance could
cause coupling of VCC or GND to DE. These factors could
improperly enable the driver.
The MAX3293/MAX3294/MAX3295 eliminate all above
issues with hot-swap circuitry. When VCC rises, an inter-
nal pulldown circuit holds DE low for approximately 10µs.
After the initial power-up sequence, the pulldown circuit
becomes transparent, resetting the hot-swap tolerable
input.
Figure 7. Differential Power-Up Glitch (0.1V/µs)
Figure 6. Simplified Structure of the Driver Enable Input (DE)
X = Don’t care.
Table 1. MAX3293/MAX3294/
MAX3295 (RS-485/RS-422) Transmitting
Function Table
INPUTS OUTPUTS
DE DI Y Z
0 X Shutdown Shutdown
1 0 0 1
1 1 1 0
DIFFERENTIAL POWER-UP GLITCH
(0.1V/µs)
4µs/div
2V/div
VCC
Y
Z
Y-Z
0V
10mV/div
AC-COUPLED
10mV/div
AC-COUPLED
20mV/div
VCC
TIMER
TIMER
EN
DE
(HOT SWAP)
10µs
100µA
M1 M2
5.6k
2mA
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
9
f j}; Figure 8. Drflerenna/ PowerrUp 6mm (1V/us) _/— ,JVLWA Figure 9. Drflerenlra/ PowerrUp Glitch HOV/us) Figure 10. Human Body ESD Test 4L Figure 11 Current Wave/arm
Hot-Swap Input Circuitry
The MAX3293/MAX3294/MAX3295 enable input
features hot-swap capability. At the input, there are
two NMOS devices, M1 and M2 (Figure 6). When
VCC ramps from zero, an internal 10µs timer turns on
M2 and sets the SR latch, which also turns on M1.
Transistors M2, a 2mA current sink, and M1, a 100µA
current sink, pull DE to GND through a 5.6k resistor.
M2 is designed to pull DE to the disabled state against
an external parasitic capacitance up to 100pF that may
drive DE high. After 10µs, the timer deactivates M2
while M1 remains on, holding DE low against three-
state leakages that can drive DE high. M1 remains on
until an external source overcomes the required input
current. At this time, the SR latch resets and M1 turns
off. When M1 turns off, DE reverts to a standard,
high-impedance CMOS input. Whenever VCC drops
below 1V, the hot-swap input is reset.
Hot-Swap Line Transient
During a hot-swap event when the driver is connected to
the line and is powered up, the driver must not cause the
differential signal to drop below 200mV. Figures 7, 8, and
9 show the results of the MAX3295 during power-up for
three different VCC ramp rates (0.1V/µs, 1V/µs, and 10V/
µs). The photos show the VCC ramp, the single-ended
signal on each side of the 100 termination, as well as
the differential signal across the termination.
ESD Protection
Human Body Model
Figure 10 shows the Human Body Model, and Figure 11
shows the current waveform it generates when discharged
into low impedance. This model consists of a 100pF capac-
itor charged to the ESD voltage of interest, which is then
discharged into the device through a 1.5k resistor.
Figure 11. Current Waveform
Figure 10. Human Body ESD Test
Figure 9. Differential Power-Up Glitch (10V/µs)
Figure 8. Differential Power-Up Glitch (1V/µs)
IP 100%
90%
36.8%
tRL
TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
10%
0V
0V
AMPERES
CHARGE-CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
100pF
RC
1M
RD
1.5k
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
DIFFERENTIAL POWER-UP GLITCH
(10V/µs)
200ns/div
2V/div
VCC
Y
Z
Y-Z
0V
50mV/div
AC-COUPLED
50mV/div
AC-COUPLED
100mV/div
DIFFERENTIAL POWER-UP GLITCH
(1V/µs)
1µs/div
2V/div
VCC
Y
Z
Y-Z
0V
100mV/div
AC-COUPLED
100mV/div
AC-COUPLED
200mV/div
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
10
W Figure 13. Drive/Output Waveform and FFT Plot 0/ MAX3293
Reduced EMI and Reflections
(MAX3293/MAX3294)
The MAX3293/MAX3294 are slew-rate limited, minimiz-
ing EMI and reducing reflections caused by improperly
terminated cables. Figure 12 shows Fourier analysis of the
MAX3295 transmitting a 125kHz signal. High-frequency
harmonics with large amplitudes are evident. Figure 13
shows the same information, but for the slew-rate-limited
MAX3293, transmitting the same signal. The high-fre-
quency harmonics have much lower amplitudes, and the
potential for EMI is significantly reduced.
To minimize reflections, the line should be terminated at
both ends in its characteristic impedance, and stub lengths
off the main line should be kept as short as possible. The
slew-rate-limited MAX3293 and MAX3294 are more toler-
ant of imperfect termination.
Driver-Output Protection
Two mechanisms prevent excessive output current and
power dissipation caused by faults or by bus contention.
The first, a foldback current limit on the output stage,
provides immediate protection against short circuits over
the whole common-mode voltage range (see the Typical
Operating Characteristics). The second, a thermal-shut-
down circuit, forces the driver outputs into a high-imped-
ance state if the die temperature exceeds +160°C.
Figure 13. Driver-Output Waveform and FFT Plot of MAX3293
Transmitting a 125kHz Signal
Figure 12. Driver-Output Waveform and FFT Plot of MAX3295
Transmitting a 125kHz Signal
VCC
ZDE
1 6 Y
+
5 GND
DI
MAX3293
MAX3294
MAX3295
SOT23-6
TOP VIEW
2
3 4
DRIVER-OUTPUT WAVEFORM AND
FFT PLOT OF MAX3293
10dB/div
DRIVER-OUTPUT WAVEFORM AND
FFT PLOT OF MAX3295
10dB/div
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
www.maximintegrated.com Maxim Integrated
11
Chip Information
PROCESS: BiCMOS
Pin Configuration
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
3 3/11 Added lead-free parts to the Ordering Information and Selector Guide tables 1
4 12/14 Added MAX3295AUT/V+T to Ordering Information 1
54/19 Added AEC-Q100 qualified MAX3295AUT/V+T in Features, move and added Package
Information table with Thermal Characteristics information 1, 2
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters
© 2019 Maxim Integrated Products, Inc.
12
Revision History
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.

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