Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsInterface ICsInterface IC - transceivers RS422, RS485 1/1 uMAX 10

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_______________General Description

The MAX1481/MAX1484/MAX1485/MAX1486 provide

software-selectable, half-/full-duplex, low-power, slew-

rate-limited, and high-speed (12Mbps) RS-485/RS-422

operation in a 10-pin µMAX

package—the smal-

lest 10-pin package available.

The software-selectable, half-/full-duplex MAX1485/

MAX1486 make obsolete the normally larger and more

expensive solutions required for selectable half-/full-

duplex RS-485/RS-422 operation: 1) a 14-pin, full-

duplex transceiver configured via jumpers between

receiver and transmitter lines, or 2) two 8-pin, half-

duplex transceivers, which require an additional invert-

er logic gate for software selectability.

The MAX1481/MAX1484 are functionally equivalent to

the industry-standard MAX491 and 75180, and are

designed for space-constrained, full-duplex RS-422

applications.

All parts contain one driver and one receiver and fea-

ture a 1/8-unit-load receiver input impedance, allowing

up to 256 transceivers on the bus. The MAX1481/

MAX1485 feature reduced-slew-rate drivers that mini-

mize EMI and reduce reflections caused by improperly

terminated cables, allowing error-free data transmission

up to 250kbps. The MAX1484/MAX1486 driver slew

rates are not limited, allowing them to transmit up to

12Mbps.

The MAX1481/MAX1484/MAX1485/MAX1486 draw only

300µA of supply current. The MAX1481 has a low-power

shutdown mode that reduces supply current to only

0.1µA. All devices operate from a single 5V supply.

Drivers are output short-circuit current limited and are

protected against excessive power dissipation by

thermal-shutdown circuitry that places the driver outputs

into a high-impedance state. The receiver input has a fail-

safe feature that guarantees a logic-high output if the

input is open circuit.

____________________________Features

♦ 10-Pin µMAX Package: Smallest 10-Pin Package

♦ Software-Selectable Half-/Full-Duplex Operation

(MAX1485/MAX1486)

♦ 0.1µA Low-Current Shutdown Mode (MAX1481)

♦ Slew-Rate Limiting Allows Error-Free Data

Transmission (MAX1481/MAX1485)

♦ 12Mbps High-Speed Operation

(MAX1484/MAX1486)

♦ Allow up to 256 Transceivers on the Bus

________________________Applications

Low-Power RS-422/RS-485 Communications

Level Translators

Hand-Held Equipment

Battery-Powered Equipment

Transceiver for EMI-Sensitive Applications

Industrial-Control Local Area Networks

MAX1481/MAX1484/MAX1485/MAX1486

Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited,

12Mbps, RS-485/RS-422 Transceivers in µMAX Package

________________________________________________________________

Maxim Integrated Products

19-1312; Rev 1; 3/06

PART

MAX1481CUB

MAX1481EUB

MAX1484CUB

0°C to +70°C

-40°C to +85°C

0°C to +70°C

TEMP RANGE PIN-PACKAGE

10 µMAX

______________Ordering Information

______________________________________________________________Selection Table

Half/Full

Duplex

Data

Rate

(Mbps)

MAX1481 Full 0.250

MAX1484 Full 12

Part

MAX1485 Selectable 0.250

MAX1486 Selectable 12

Slew-

Rate

Limited

Yes

Low-

Power

Shutdown

Driver

Enable

Yes Yes

No Yes

Quiescent

Current

(µA)

300

Transceivers

on Bus

256

Pin-

Package

10 µMAX

MAX1484EUB -40°C to +85°C 10 µMAX

Receiver

Enable

Yes

MAX1485CUB

MAX1485EUB

MAX1486CUB

0°C to +70°C

-40°C to +85°C

0°C to +70°C 10 µMAX

10 µMAX

MAX1486EUB -40°C to +85°C 10 µMAX

________________________________________________________________ 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.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Summary of content (16 pages)

PAGE 1
9-1312; Rev 1; 3/06 Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package The MAX1481/MAX1484 are functionally equivalent to the industry-standard MAX491 and 75180, and are designed for space-constrained, full-duplex RS-422 applications. All parts contain one driver and one receiver and feature a 1/8-unit-load receiver input impedance, allowing up to 256 transceivers on the bus.
PAGE 2
MAX1481/MAX1484/MAX1485/MAX1486 Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC) ............................................................+7V Control Input Voltage (RE, DE, H/F) ...........-0.3V to (VCC + 0.3V) Driver Input Voltage (DI).............................-0.3V to (VCC + 0.3V) Driver Output Voltage (A, B, Y, Z) ..........................-8V to +12.
PAGE 3
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package (VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.
PAGE 4
MAX1481/MAX1484/MAX1485/MAX1486 Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package SWITCHING CHARACTERISTICS (MAX1481/MAX1485) (continued) (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.
PAGE 5
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package 300 280 MAX1484/MAX1486 260 40 30 20 220 -20 0 20 40 60 80 100 2 3 4 5 2 3 4 5 OUTPUT LOW VOLTAGE (V) SHUTDOWN CURRENT vs. TEMPERATURE RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE IRO = 8mA 0.45 0.40 IRO = 8mA 4.4 OUTPUT VOLTAGE (V) 102 4.5 MAX1481/4/5/6-05 MAX1481/4/5/6-04 106 0.50 98 0.35 0.30 0.25 0.
PAGE 6
_________________________________Typical Operating Characteristics (continued) (VCC = +5V, TA = +25°C, unless otherwise noted.) 30 26 120 100 80 60 40 22 -40 -20 0 20 40 60 80 100 80 60 40 0 0 0 2 4 6 8 10 -8 12 -6 -4 -2 0 2 4 TEMPERATURE (°C) OUTPUT LOW VOLTAGE (V) OUTPUT HIGH VOLTAGE (V) DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE MAX1484/MAX1486 RECEIVER PROPAGATION DELAY RDIFF = 54Ω 2.35 2.30 2.25 2.
PAGE 7
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package PIN PIN MAX1481/ MAX1484 MAX1485/MAX1486 NAME FUNCTION H/F = 0 H/F = 1 1 1 1 RO Receiver Output. When RE is low and if A - B ≥ 200mV, RO goes high; if A - B ≤ -200mV, RO goes low. — 2 2 H/F Half-/Full-Duplex Selector Input. Connect H/F to VCC for half-duplex mode, and connect to GND for full-duplex mode. 2 — — RE Receiver Output Enable Input.
PAGE 8
MAX1481/MAX1484/MAX1485/MAX1486 Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package _____________________________________________________________Function Tables MAX1481 RECEIVING TRANSMITTING INPUTS INPUTS OUTPUTS OUTPUT RE DE DI Z Y RE DE A-B RO X 1 1 0 1 0 X ≥ 0.2V 1 X 1 0 1 0 0 X ≤ -0.
PAGE 9
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package MAX1481 MAX1484 RO 1 MAX1481 MAX1484 0.1µF MAX1481 MAX1484 10 VCC RE 2 9 A DE 3 8 Y DI 4 7 Z GND 5 6 B RO RE DE DI 1 10 VCC 9 A 0.1µF Rt Y 8 7 Z 6 B 2 10 VCC Rt 7 Z 8 Y 5 µMAX B 6 9 A 1 5 GND 4 DI 3 DE 2 RE 3 4 MAX1481/MAX1484/MAX1485/MAX1486 TOP VIEW RO GND Figure 1.
PAGE 10
MAX1481/MAX1484/MAX1485/MAX1486 Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package MAX1485/MAX1486 Half-/Full-Duplex Mode Operation VCC DI MAX1485 MAX1486 Z Y DE The MAX1484/MAX1485 can operate in full- or halfduplex mode. Drive the H/F pin low or connect it to GND for full-duplex operation, or drive it high for halfduplex operation. In full-duplex mode, the pin configuration of the driver and receiver is the same as a MAX1481 (Figure 1).
PAGE 11
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package MAX1481/MAX1484/MAX1485/MAX1486 Y R RECEIVER OUTPUT VOD 1k TEST POINT VCC S1 CL R 1k VOC S2 Z Figure 5. Driver DC Test Load Figure 6. Receiver Enable/Disable Timing Test Load 3V DE CL1 Y DI RDIFF VID VCC S1 500Ω OUTPUT UNDER TEST Z CL CL2 S2 Figure 7. Driver Timing Test Circuit Figure 8. Driver Enable/Disable Timing Test Load 3V DI 1.5V 0V 3V 1.
PAGE 12
3V RE 1.5V 1.5V 0V RO VOH 1.5V VOL 1V A -1V B RPHL RZL(SHDN), RZL 1.5V OUTPUT RPLH RLZ VCC RO 1.5V OUTPUT NORMALLY LOW RO 1.5V INPUT VOL + 0.5V OUTPUT NORMALLY HIGH VOH - 0.5V 0V RZH(SHDN), RZH Figure 11. Receiver Propagation Delays RHZ Figure 12.
PAGE 13
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package Figures 17 and 18 show the system differential voltage for the parts driving 4000 feet of 26AWG twisted-pair wire into 120Ω loads. Typical Applications To minimize reflections, terminate the line at both ends in its characteristic impedance, and keep stub lengths off the main line as short as possible.
PAGE 14
MAX1481/MAX1484/MAX1485/MAX1486 Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package 5V VCC 5V H/F 120Ω H/F DE (Z) Z DI VCC 120Ω D D DI DE RO Y Z Y Z R (Y) Y R 5V R H/F R VCC D D VCC VCC MAX1485 MAX1486 DI DE RO DI DE RO Figure 19.
PAGE 15
Software-Selectable, Half-/Full-Duplex, Slew-Rate-Limited, 12Mbps, RS-485/RS-422 Transceivers in µMAX Package Y 120Ω R RO RE 120Ω D B Z Z B DI DE DI MAX1481/MAX1484/MAX1485/MAX1486 A DE 120Ω D Y 120Ω Z Y B A Y Z B A RE* RO R A H/F** H/F** R D DI R H/F** DE RE* RO H/F** D DI DE RE* RO MAX1481 MAX1484 MAX1485 MAX1486 *RE ON MAX1481 AND MAX1484 ONLY. **H/F ON MAX1485 AND MAX1486 ONLY. Figure 20.
PAGE 16
Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) ________________________________________________________Package Information 10LUMAXB.