MAXIM MAX3293, MAX3294, MAX3295 User Manual

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General Description

The MAX3293/MAX3294/MAX3295 low-power, high­speed 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 guar­anteed 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 low­power 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 thermal­shutdown 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)

MAX3293/MAX3294/MAX3295

20Mbps, +3.3V, SOT23 RS-485/

RS-422 Transmitters

________________________________________________________________ Maxim Integrated Products 1

Selector Guide

Ordering Information

19-2770; Rev 1; 2/03

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.

PART TEMP RANGE

PIN­PACKAGE

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

Typical Operating Circuit

MAX3293
MAX3294
MAX3295

D

DI

DE

MAX3280E
MAX3281E
MAX3283E
MAX3284E

R

RO

120Ω

Z

Y

Pin Configuration

MAXIMUM

PART

MAX3293AUT-T 0.25 Yes ABNI
MAX3294AUT-T 2.5 Yes ABNJ
MAX3295AUT-T 20 No ABNK

DATA RATE

(Mbps)

SLEW-RATE

LIMITED

MARK

TOP

TOP VIEW

16Y

DI

V

CC

MAX3293

2

MAX3294
MAX3295

34

SOT23-6

5 GND

ZDE

MAX3293/MAX3294/MAX3295

20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V ±5%, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VCC= +3.3V and TA= +25°C.) (Notes 1, 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.

(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)

6-Pin SOT23 (derate 6.25mW/°C above +70°C).........500mW

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

PARAMETER

CONDITIONS

UNITS

POWER SUPPLY

Supply Voltage V

CC

V

Supply Current in Normal
Operation

I

Q

No load, DI = VCC or GND, DE = V

CC

5mA

I

SHDN

No load, DE = GND 1 10 µA

DRIVER

R = 50Ω (RS-422),
T

A

≤ +85°C

2.0

Differential Driver Output V

OD

Figure 1, DE = VCC,
DI = GND or V

CC

R = 27Ω (RS-485),
T

A

≤ +85°C

1.5

V

Change in Magnitude of
Differential Output Voltage

∆V

OD

Figure 1, R = 27Ω or 50Ω,
DE = V

CC

(Note 3)

0.2 V

Driver Common-Mode Output
Voltage

V

OC

Figure 1, R = 27Ω or 50Ω,
DE = V

CC

, DI = VCC or GND

-1 +3 V

Change in Magnitude of Common­Mode Voltage

∆V

OC

Figure 1, R = 27Ω or 50Ω (Note 3) 0.2 V

DRIVER LOGIC

Input High Voltage V

IH

DE, DI 2.0 V

Input Low Voltage V

IL

DE, DI 0.8 V

Input Current I

IN

DE, DI -2 +2 µA

VIN = +12V -20

Output Leakage I

O

Y, Z
DE = GND,
V

CC

= GND or

+3.3V

VIN = -7V -20

µA

(VCC - 1V) ≤ V

OUT

≤ +12V, output high

Driver Short-Circuit Foldback
Output Current

I

OSFD

-7V ≤ V

OUT

≤ 1V, output high -25

mA

0 ≤ V

OUT

≤ +12V, output low

Driver Short-Circuit
Output Current

I

OSD

-7V ≤ V

OUT

≤ VCC, output high

mA

Thermal-Shutdown Threshold T

TS

°C

Thermal-Shutdown Hysteresis T

TSH

40 °C

ESD Protection Y, Z Human Body Model ±9 kV

Supply Current in Shutdown Mode

SYMBOL

MIN TYP MAX

3.135 3.300 3.465

V

CC

V

CC

+20

+20

+250

+25

-250

160

MAX3293/MAX3294/MAX3295

20Mbps, +3.3V, SOT23 RS-485/

RS-422 Transmitters

_______________________________________________________________________________________ 3

SWITCHING CHARACTERISTICS (MAX3293)

(VCC= +3.3V ±5%, TA= +25°C, unless otherwise noted. Typical values are at VCC= +3.3V.)

SWITCHING CHARACTERISTICS (MAX3294)

(VCC= +3.3V ±5%, TA= +25°C, unless otherwise noted. Typical values are at VCC= +3.3V.)

PARAMETER

CONDITIONS

UNITS

t

PLH

Driver Propagation Delay

t

PHL

Figures 2, 3; R

DIFF

= 54Ω,

C

L

= 50pF

ns

t

R

Driver Differential Output Rise
or Fall Time

t

F

Figures 2, 3; R

DIFF

= 54Ω,

C

L

= 50pF

ns

Driver Output Skew t

SKEW

Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF,

t

SKEW

= | t

PLH

- t

PHL

| (Note 5)

ns

Differential Driver Output Skew

Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF

ns

Maximum Data Rate Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF

kbps

Driver Enable to Output High t

ZH

Figures 4, 5; S2 closed, RL = 500Ω,
C

L

= 100pF

ns

Driver Enable to Output Low t

ZL

Figures 4, 5; S1 closed, RL = 500Ω,
C

L

= 100pF

ns

Driver Disable Time from Low t

LZ

Figures 4, 5; S1 closed, RL = 500Ω,
C

L

= 100pF

ns

Driver Disable Time from High t

HZ

Figures 4, 5; S2 closed, RL = 500Ω,
C

L

= 100pF

ns

Device-to-Device Propagation
Delay Matching

Same power supply, maximum temperature

900 ns

SYMBOL

t

DSKEW

difference between devices = +30°C (Note 5)

MIN TYP MAX

400 1300
400 1300
400 1200
400 1200

-400 +400

-100 +100
250

2000

2000

1000

1000

Driver Propagation Delay

Driver Differential Output Rise
or Fall Time

Driver Output Skew t

Differential Driver Output Skew t
Maximum Data Rate Figures 2, 3; R

Driver Enable to Output High t

Driver Enable to Output Low t

Driver Disable Time from Low t

Driver Disable Time from High t

Device-to-Device Propagation
Delay Matching

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

t

PLH

t

PHL

t

R

t

F

SKEW

DSKEW

ZH

ZL

LZ

HZ

Figures 2, 3; R
C

= 50pF

L

Figures 2, 3; R
C

= 50pF

L

Figures 2, 3; R

= | t

t

SKEW

Figures 2, 3; R

Figures 4, 5; S2 closed, RL = 500Ω,

= 100pF

C

L

Figures 4, 5; S1 closed, RL = 500Ω,

= 100pF

C

L

Figures 4, 5; S1 closed, RL = 500Ω,

= 100pF

C

L

= 54Ω,

DIFF

= 54Ω,

DIFF

= 54Ω, CL = 50pF,

DIFF

- t

PLH

| (Note 5)

PHL

= 54Ω, CL = 50pF -6 +6 ns

DIFF

= 54Ω, CL = 50pF 2.5 Mbps

DIFF

Figures 4, 5; S2 closed, RL = 500Ω,

= 100pF

C

L

Same power supply, maximum temperature
difference between devices = +30°C (Note 5)

24 70
24 70
10 70
10 70

ns

ns

-40 +40 ns

400 ns

400 ns

100 ns

100 ns

46 ns

MAX3293/MAX3294/MAX3295

20Mbps, +3.3V, SOT23 RS-485/
RS-422 Transmitters

4 _______________________________________________________________________________________

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: ∆V

OD

and ∆VOCare the changes in VODand 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: Not production tested. Guaranteed by design.

SWITCHING CHARACTERISTICS (MAX3295)

(VCC= +3.3V ±5%, TA= +25°C, unless otherwise noted. Typical values are at VCC= +3.3V.)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

t

PLH

25

Driver Propagation Delay

t

PHL

Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF

25

ns

t

R

TA < +85°C 15

Driver Differential Output Rise
or Fall Time

t

F

Figures 2, 3;
R

DIFF

= 54Ω,

C

L

= 50pF

T

A

< +85°C 15

ns

Driver Output Skew t

SKEW

Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF,

t

SKEW

= | t

PLH

- t

PHL

|

5ns

Differential Driver Output Skew

Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF 5 ns

Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF,

T

A

≤ +85°C

20

Maximum Data Rate

Figures 2, 3; R

DIFF

= 54Ω, CL = 50pF 16

Mbps

Driver Enable to Output High t

ZH

Figures 4, 5; S2 closed, RL = 500Ω,
C

L

= 100pF

ns

Driver Enable to Output Low t

ZL

Figures 4, 5; S1 closed, RL = 500Ω,
C

L

= 100pF

ns

Driver Disable Time from Low t

LZ

Figures 4, 5; S1 closed, RL = 500Ω,
C

L

= 100pF

ns

Driver Disable Time from High t

HZ

Figures 4, 5; S2 closed, RL = 500Ω,
C

L

= 100pF

ns

Device-to-Device Propagation
Delay Matching

Same power supply, maximum temperature

25 ns

TA = -40°C to +125°C 18.5

TA = -40°C to +125°C 18.5

t

DSKEW

400

400

difference between devices = +30°C (Note 5)

100

100