Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsInterface ICsInterface IC - transceivers RS422, RS485 1/1 uMAX 8

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_______________General Description

The MAX1482 and MAX1483 are low-power trans-

ceivers for RS-485 and RS-422 communication. Both

feature slew-rate-limited drivers that minimize EMI and

reduce reflections caused by improperly terminated

cables. Data rates are guaranteed up to 250kbps.

The MAX1482/MAX1483 draw only 20µA of supply cur-

rent. Additionally, they have a low-current shutdown

mode that consumes only 0.1µA. Both parts operate

from a single +5V supply.

Drivers are short-circuit current limited and are protect-

ed 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.

The MAX1482 is full duplex and the MAX1483 is half

duplex. Both parts have a

⁄

-unit-load input impedance

that guarantees up to 256 transceivers on the bus.

________________________Applications

Low-Power RS-485/RS-422 Networks

Transceivers for EMI-Sensitive Applications

Industrial-Control Local Area Networks

Large 256-Node LANs

____________________________Features

♦ Low 20µA Operating Current

♦ Slew-Rate Limited for Reduced EMI and

Reduced Reflections

♦ 0.1µA Low-Current Shutdown Mode

♦ Designed for RS-485 and RS-422 Applications

♦ Operate from a Single +5V Supply

♦ -7V to +12V Common-Mode Input Voltage Range

♦ Allows up to 256 Transceivers on the Bus—

Guaranteed (

⁄

-unit load)

♦ Current Limiting and Thermal Shutdown for

Driver Overload Protection

MAX1482/MAX1483

20µA,

⁄

-Unit-Load, Slew-Rate-Limited

RS-485 Transceivers

________________________________________________________________ Maxim Integrated Products 1

TOP VIEW

GND

DIP/SO

GND

µMAX

MAX1483

_________________Pin Configurations

MAX1483

NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM

DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.

TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.

+5V

GND

_________Typical Operating Circuits

19-0367; Rev 1; 5/06

MAX1482 appears at end of data sheet.

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX1482CPD

0°C to +70°C

14 PDIP

P14-3

MAX1482CSD

0°C to +70°C

14 SO

S14-4

MAX1482EPD

-40°C to +85°C

14 PDIP

P14-3

MAX1482ESD

-40°C to +85°C

14 SO

S14-4

MAX1483CPA

0°C to +70°C

8 PDIP P8-1

MAX1483CSA

0°C to +70°C

8 SO S8-5

MAX1483CUA

0°C to +70°C

8 µMAX

U8-1

MAX1483EPA

-40°C to +85°C

8 PDIP P8-1

MAX1483ESA

-40°C to +85°C

8 SO S8-5

Ordering Information

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

Summary of content (14 pages)

PAGE 1
9-0367; Rev 1; 5/06 20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers The MAX1482 and MAX1483 are low-power transceivers for RS-485 and RS-422 communication. Both feature slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly terminated cables. Data rates are guaranteed up to 250kbps. The MAX1482/MAX1483 draw only 20µA of supply current. Additionally, they have a low-current shutdown mode that consumes only 0.1µA. Both parts operate from a single +5V supply.
PAGE 2
MAX1482/MAX1483 20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC) ...............................................................7V Control Input Voltages (RE, DE) .................-0.5V to (VCC + 0.5V) Driver Input Voltage (DI).............................-0.5V to (VCC + 0.5V) Driver Output Voltages ..........................................-7.5V to 12.5V Receiver Input Voltages (A, B) ..............................-7.5V to 12.
PAGE 3
20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers (VCC = 5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
__________________________________________Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) RECEIVER PROPAGATION DELAY vs. TEMPERATURE DRIVER PROPAGATION DELAY vs. TEMPERATURE 1000 900 1000 900 800 700 600 500 800 -20 0 20 40 60 80 100 DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE -20 2.0 80 60 0 20 40 60 80 OUTPUT CURRENT vs.
PAGE 5
20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers PIN MAX1482 DIP/SO MAX1483 DIP/SO µMAX NAME FUNCTION 2 1 3 RO Receiver Output. With the receiver output enabled (RE low), RO is high if A > B by 200mV or when A and B are not connected, and RO is low if A < B by 200mV. 3 2 4 RE Receiver Output Enable. When RE is low, RO is enabled. When RE is high, RO is high impedance. If RE is high and DE is low, the MAX1482/MAX1483 enter a low-power (0.1µA) shutdown state.
PAGE 6
MAX1482/MAX1483 20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers _________________________________________________________________Test Circuits Y VOD R 1k TEST POINT RECEIVER OUTPUT CRL 15pF R VCC S1 1k VOC S2 Z Figure 1. Driver DC Test Load 3V DE DI Figure 2. Receiver Timing Test Load CL1 Y A RDIFF VID RO B Z RE CL2 Figure 3. Driver/Receiver Timing Test Circuit 6 500Ω S1 OUTPUT UNDER TEST CL S2 Figure 4.
PAGE 7
20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers 3V 3V DI 1.5V 0V DE 1.5V tPHL tPLH 1.5V 1.5V 0V 1/2 VO tZL(SHDN), tZL Z tLZ Y, Z VO 2.3V OUTPUT NORMALLY LOW VOL Y 1/2 VO VO VDIFF 0V -VO 10% VDIFF = V (Y) - V (Z) tR OUTPUT NORMALLY HIGH Y, Z VOH - 0.5V 2.3V 90% 90% 0V 10% VOL + 0.5V tZH(SHDN), tZH tF tHZ tSKEW = | tPLH - tPHL | Figure 5. Driver Propagation Delays Figure 6. Driver Enable and Disable Times 3V RE 1.5V 1.5V 0V RO A-B VOH 1.
PAGE 8
MAX1482/MAX1483 20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers 100pF Z TTL IN tR, tF < 6ns B RECEIVER OUT R D R = 54Ω Y A 10dB/div 100pF 0Hz 500kHz/div 5MHz Figure 9. Driver Output Waveform and FFT, Transmitting 250kbps (125kHz) Signal Figure 10. Receiver Propagation-Delay Test Circuit Table 1. Transmitting Table 2. Receiving INPUTS OUTPUTS INPUTS OUTPUT RE DE DI Z Y RE DE* A-B RO X 1 1 0 1 0 0 > +0.2V 1 X 1 0 1 0 0 0 < -0.
PAGE 9
20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers B 500mV/div 500mV/div B A RO 5V/div 5V/div RO 500ns/div 500ns/div Figure 11. Receiver tPHL MAX1482/MAX1483 A Figure 12. Receiver tPLH Low-Power Shutdown Mode Driver Output Protection A low-power shutdown mode is initiated by bringing RE high and DE low. The devices will not shut down unless both the driver and receiver are disabled. In shutdown, the devices typically draw only 0.1µA of supply current.
PAGE 10
MAX1482/MAX1483 20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers Line Length vs. Data Rate 5 DI 0 1 RECEIVER INPUT VY-VZ The RS-485/RS-422 standard covers line lengths up to 4000 feet. For line lengths greater than 4000 feet, see Figure 16. Figure 13 shows the system differential voltage for the parts driving 4000 feet of 26AWG twisted-pair wire at 110kHz into 120Ω loads. Even after 4000 feet of cable, the MAX1482/MAX1483 output shows virtually no distortion.
PAGE 11
20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers Y 120Ω R RO RE MAX1482/MAX1483 A 120Ω D B Z Z B DI DE DE DI 120Ω D Y 120Ω Z Y B A Y Z B A R A R MAX1482 D D DI RE RO R DE RE RO DI DE RE RO NOTE: RE AND DE ON. Figure 15.
PAGE 12
MAX1482/MAX1483 20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers ____Pin Configurations (continued) TOP VIEW __________________Chip Information TRANSISTOR COUNT: 294 MAX1482 N.C. 1 14 VCC R RO 2 13 N.C. RE 3 12 A DE 4 11 B 10 Z DI 5 D GND 6 9 Y 8 N.C. GND 7 DIP/SO 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.) DIM C α A 0.101mm 0.
PAGE 13
20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers N E H INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .EPS DIM A A1 B C e E H L 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.
PAGE 14
Package Information (continued) (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.) PDIPN.EPS MAX1482/MAX1483 20µA, 1⁄8-Unit-Load, Slew-Rate-Limited RS-485 Transceivers Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.