Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsInterface ICsInterface IC - drivers RS422, RS485 1/0 SOT 23 6

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 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 ther-

mal-shutdown circuitry protect the driver against exces-

sive 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)

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

MAX3280E

MAX3281E

MAX3283E

MAX3284E

120Ω

MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/

RS-422 Transmitters

19-2770; Rev 4; 12/14

Selector Guide

Ordering Information

Typical Operating Circuit

Summary of content (11 pages)

PAGE 1
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters 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.
PAGE 2
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Absolute Maximum Ratings (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)..........
PAGE 3
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Switching Characteristics (MAX3293) (VCC = +3.3V ±5%, TA = +25°C, unless otherwise noted. Typical values are at VCC = +3.3V.
PAGE 4
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Switching Characteristics (MAX3295) (VCC = +3.3V ±5%, TA = +25°C, unless otherwise noted. Typical values are at VCC = +3.3V.) PARAMETER Driver Propagation Delay Driver Differential Output Rise or Fall Time Driver-Output Skew Differential Driver-Output Skew SYMBOL tPLH tPHL tR tF CONDITIONS MIN TYP 25 Figures 2, 3; RDIFF = 54W, CL = 50pF Figures 2, 3; RDIFF = 54W, CL = 50pF MAX 25 TA = -40°C to +125°C UNITS ns 18.
PAGE 5
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Test Circuits and Timing Diagrams Y R OUTPUT UNDER TEST VOD R CL VOC S2 Z Figure 1. Driver DC Test Load Figure 4. Enable/Disable Timing Test Load DE 3V DE DI 3V 0V Y VID CL RDIFF Z Y, Z VOL CL 1.5V 1.5V tZL(SHDN), tZL 0V 3V 0V Z Y VOL+ 0.25V OUTPUT NORMALLY HIGH 2.3V tZH(SHDN), tZH Figure 2. Driver Timing Test Circuit tLZ 2.3V OUTPUT NORMALLY LOW Y, Z DI VCC S1 RL VOH- 0.25V tHZ Figure 5.
PAGE 6
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Typical Operating Characteristics (VCC = +3.3V, TA = +25°C, unless otherwise noted.) TA = +25C TA = -40C 0 0 5 10 15 0.5 0 20 -40 -10 DATA RATE (Mbps) 20 10 2.25 2.50 2.75 3.00 3.25 3.50 3.0 RDIFF = 100Ω 2.5 2.0 RDIFF = 54Ω 140 DRIVER-OUTPUT CURRENT vs. DRIVER-OUTPUT HIGH VOLTAGE -40 -10 20 50 80 -80 110 80 60 40 0 110 0 2 2 1 4 6 8 10 OUTPUT LOW VOLTAGE (V) 12 DRIVER PROPAGATION DELAY vs.
PAGE 7
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Typical Operating Characteristics (continued) (VCC = +3.3V, TA = +25°C, unless otherwise noted.
PAGE 8
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters 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-impedance state, and the supply current reduces to 1µA.
PAGE 9
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters 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 5.6kΩ resistor.
PAGE 10
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Reduced EMI and Reflections (MAX3293/MAX3294) Driver-Output Protection The MAX3293/MAX3294 are slew-rate limited, minimizing 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.
PAGE 11
MAX3293–MAX3295 20Mbps, +3.3V, SOT23 RS-485/ RS-422 Transmitters Revision History REVISION NUMBER REVISION DATE 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 DESCRIPTION For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.