Datasheet

ManualsBrandsANALOG DEVICES ManualsInterface ICsInterface IC - transceivers RS422, RS485 1/1 SOIC 14

Full-Duplex, Low Power,

Slew Rate Limited, EIA RS-485 Transceivers

ADM488A/ADM489A

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

FEATURES

Complies with ANSI TIA/EIA-485-A-1998 and

ISO 8482: 1987(E)

250 kbps data rate

Single 5 V ± 10% supply

−7 V to +12 V bus common-mode range

Connect up to 32 nodes on the bus

Reduced slew rate for low EM interference

Short-circuit protection

30 µA supply current

APPLICATIONS

Low power RS-485 and RS-422 systems

DTE-DCE interface

Packet switching

Local area networks

Data concentration

Data multiplexers

Integrated services digital network (ISDN)

GENERAL DESCRIPTION

The ADM488A and ADM489A are low power, differential line

transceivers suitable for communication on multipoint bus

transmission lines. They are intended for balanced data

transmission and comply with both RS-485 and RS-422

standards of the Electronics Industries Association (EIA). Both

products contain a single differential line driver and a single

differential line receiver, making them suitable for full-duplex

data transfer. The ADM489A contains an additional receiver

and driver enable control.

The input impedance is 12 kΩ, allowing 32 transceivers to be

connected on the bus. The ADM488A/ADM489A operate from

a single 5 V ± 10% power supply.

FUNCTIONAL BLOCK DIAGRAMS

ADM488A

08498-001

Figure 1. ADM488A

ADM489A

08498-002

Figure 2. ADM489A

Excessive power dissipation that is caused by bus contention or

output shorting is prevented by a thermal shutdown circuit. This

feature forces the driver output into a high impedance state if,

during fault conditions, a significant temperature increase is

detected in the internal driver circuitry.

The receiver contains a fail-safe feature that results in a logic

high output state if the inputs are unconnected (floating).

The ADM488A/ADM489A are fabricated on BiCMOS, an

advanced mixed technology process combining low power

CMOS with fast switching bipolar technology.

The ADM488A/ADM489A are fully specified over the industrial

temperature range and are available in SOIC and MSOP packages.

Summary of content (16 pages)

PAGE 1
Full-Duplex, Low Power, Slew Rate Limited, EIA RS-485 Transceivers ADM488A/ADM489A FUNCTIONAL BLOCK DIAGRAMS ADM488A A B Z DI GENERAL DESCRIPTION The ADM488A and ADM489A are low power, differential line transceivers suitable for communication on multipoint bus transmission lines. They are intended for balanced data transmission and comply with both RS-485 and RS-422 standards of the Electronics Industries Association (EIA).
PAGE 2
ADM488A/ADM489A TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................8 Applications ....................................................................................... 1 Test Circuits........................................................................................9 General Description ..........................................................
PAGE 3
ADM488A/ADM489A SPECIFICATIONS VCC = 5 V ± 10%; all specifications TMIN to TMAX, unless otherwise noted. Table 1. Parameter Symbol DRIVER Differential Output Voltage VOD Min Typ 2.0 1.5 1.
PAGE 4
ADM488A/ADM489A TIMING SPECIFICATIONS VCC = 5 V ± 10%. All specifications TMIN to TMAX, unless otherwise noted. Table 2.
PAGE 5
ADM488A/ADM489A ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Table 3. Parameter VCC Inputs Driver Input (DI) Control Inputs (DE, RE) Receiver Inputs (A, B) Outputs Driver Outputs Receiver Output Power Dissipation 8-Lead SOIC θJA, Thermal Impedance Power Dissipation 14-Lead SOIC θJA, Thermal Impedance Operating Temperature Range Industrial (A Version) Storage Temperature Range Lead Temperature (Soldering, 10 sec) Vapor Phase (60 sec) Infrared (15 sec) Rating 7V −0.3 V to VCC + 0.3 V −0.
PAGE 6
ADM488A/ADM489A PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS RO 2 8 ADM488A A B TOP VIEW DI 3 (Not to Scale) 6 Z 5 Y GND 4 7 08498-003 VCC 1 Figure 3. ADM488A SOIC_N and MSOP Pin Configuration Table 4. ADM488A Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 Mnemonic VCC RO DI GND Y Z B A Description Power Supply, 5 V ± 10%. Receiver Output. When A > B by 200 mV, RO = high. If A < B by 200 mV, RO = low. Driver Input.
PAGE 7
NC 1 14 VCC RO 2 13 NC ADM489A RO 1 10 VCC RE 2 ADM489A 9 A 3 TOP VIEW (Not to Scale) 8 B RE 3 DE 4 11 B DE DI 5 10 Z DI 4 7 Z GND 6 9 Y GND 5 6 Y GND 7 8 NC 12 A NC = NO CONNECT 08498-004 TOP VIEW (Not to Scale) 08498-005 ADM488A/ADM489A Figure 5. ADM489A MSOP Pin Configuration Figure 4. ADM489A SOIC_N Pin Configuration Table 5. ADM489A Pin Function Descriptions SOIC_N 1, 8, 13 2 3 Pin No.
PAGE 8
ADM488A/ADM489A 0 40 –10 35 –20 30 25 20 15 –30 –40 –50 –60 10 –70 5 –80 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 OUTPUT VOLTAGE (V) –90 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 OUTPUT VOLTAGE (V) Figure 6. Output Current vs. Receiver Output Low Voltage 08498-018 OUTPUT CURRENT (mA) 45 08498-015 OUTPUT CURRENT (mA) TYPICAL PERFORMANCE CHARACTERISTICS Figure 9. Output Current vs.
PAGE 9
ADM488A/ADM489A TEST CIRCUITS VCC +1.5V R S1 RL S2 RE VOC R 08498-006 –1.5V CL VOUT 08498-009 VOD RE IN Figure 14. Receiver Enable/Disable Test Circuit Figure 11. Driver Voltage Measurement Test Circuit 3V DE DI Z VTST 375Ω Figure 12. Driver Enable/Disable Test Circuit A RL S1 B S2 CL VOUT DE IN 08498-008 DE R CL2 B RE Figure 15. Driver/Receiver Propagation Delay Test Circuit VCC 0V OR 3V RO RLDIFF D 08498-010 60Ω A 08498-007 VOD3 CL1 Y 375Ω Figure 13.
PAGE 10
ADM488A/ADM489A SWITCHING CHARACTERISTICS VCC VCC/2 VCC/2 VCC 0V tPLH tPHL DE 0.5VCC 0.5VCC Z 0V 1/2VO tZL VO Y tLZ 2.3V Y, Z VOL + 0.5V VOL 90% POINT tZH 90% POINT VDIFF = V(Y) – V(Z) VOH 10% POINT 10% POINT tDR tDF 08498-011 VDIFF –VO tHZ 2.3V VOH – 0.5V Y, Z 0V Figure 16. Driver Propagation Delay, Rise/Fall Timing 08498-013 +VO Figure 18. Driver Enable/Disable Timing 0.7VCC RE 0.5VCC 0.5VCC 0.3VCC 0V 0V tPLH tPHL tZL 1.5V tSKEW = |tPLH – tPHL| VOL + 0.
PAGE 11
ADM488A/ADM489A THEORY OF OPERATION The ADM488A/ADM489A are ruggedized RS-485 transceivers that operate from a single 5 V supply. They contain protection against radiated and conducted interference and are ideally suited for operation in electrically harsh environments or where cables can be plugged/unplugged. They are also immune to high RF field strengths without special shielding precautions.
PAGE 12
ADM488A/ADM489A MAXIMUM NUMBER OF NODES = 32 VCC MASTER SLAVE A R RO B Y D RT DE Z DE DI DI Z RE D B RT Y A RE R RO VCC ADM488A ADM488A A B Z Y A B Z Y SLAVE R ADM488A R D RO RE DE D DI RO RE DE NOTES 1. RT IS EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE CABLE. Figure 21. Typical RS-485 Full-Duplex Application Rev.
PAGE 13
ADM488A/ADM489A APPLICATIONS INFORMATION DIFFERENTIAL DATA TRANSMISSION CABLE AND DATA RATE Differential data transmission reliably transmits data at high rates over long distances and through noisy environments. Differential transmission nullifies the effects of ground shifts and noise signals, which appear as common-mode voltages on the line. Two main standards that specify the electrical characteristics of transceivers used in differential data transmission are approved by the EIA.
PAGE 14
ADM488A/ADM489A OUTLINE DIMENSIONS 3.20 3.00 2.80 8 3.20 3.00 2.80 5.15 4.90 4.65 5 1 4 PIN 1 IDENTIFIER 0.65 BSC 0.95 0.85 0.75 15° MAX 1.10 MAX 0.80 0.55 0.40 0.23 0.09 6° 0° 0.40 0.25 10-07-2009-B 0.15 0.05 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-AA Figure 23. 8-Lead Mini Small Outline Package [MSOP] (RM-8) Dimensions shown in millimeters 5.00 (0.1968) 4.80 (0.1890) 1 5 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) COPLANARITY 0.10 SEATING PLANE 6.20 (0.2441) 5.80 (0.
PAGE 15
ADM488A/ADM489A 3.10 3.00 2.90 10 3.10 3.00 2.90 5.15 4.90 4.65 6 1 5 PIN 1 IDENTIFIER 0.50 BSC 0.95 0.85 0.75 15° MAX 1.10 MAX 0.30 0.15 0.23 0.13 6° 0° 0.70 0.55 0.40 091709-A 0.15 0.05 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-BA Figure 25. 10-Lead Mini Small Outline Package [MSOP] (RM-10) Dimensions shown in millimeters 8.75 (0.3445) 8.55 (0.3366) 8 14 1 7 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0039) COPLANARITY 0.10 0.51 (0.0201) 0.31 (0.0122) 6.20 (0.2441) 5.80 (0.