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ADM307xE

3.3 V, ±15 kV ESD-Protected, Half- and

Full-Duplex, RS-485/RS-422 Transceivers ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E

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. T rademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, N orwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 https://www.wendangku.net/doc/8b12666867.html, Fax: 781.461.3113 ?2006–2009 Analog Devices, Inc. All rights reserved.

FEATURES

TIA/EIA RS-485/RS-422 compliant

±15 kV ESD protection on RS-485 input/output pins

Data rates

ADM3070E/ADM3071E/ADM3072E: 250 kbps

ADM3073E/ADM3074E/ADM3075E: 500 kbps

ADM3076E/ADM3077E/ADM3078E: 16 Mbps

Half- and full-duplex options

True fail-safe receiver inputs

Up to 256 nodes on the bus

?40°C to +125°C temperature option

Hot-swap input structure on DE and RE pins

Reduced slew rates for low EMI

Low power shutdown current (all except ADM3071E/

ADM3074E/ADM3077E)

Outputs high-Z when disabled or powered off

Common-mode input range: ?7 V to +12 V

Thermal shutdown and short-circuit protection

8-lead and 14-lead narrow SOIC packages APPLICATIONS

Power/energy metering

Industrial control

Lighting systems

Telecommunications

Security systems

Instrumentation

GENERAL DESCRIPTION

The ADM307xE are 3.3 V, low power data transceivers with

±15 kV ESD protection suitable for full- and half-duplex communication on multipoint bus transmission lines. They are designed for balanced data transmission, and they comply with TIA/EIA standards: RS-485 and RS-422.

The devices have a ? unit load receiver input impedance, which allows up to 256 transceivers on a bus. Because only one driver should be enabled at any time, the output of a disabled or powered-down driver is tristated to avoid overloading the bus.

The receiver inputs have a true fail-safe feature, which eliminates the need for external bias resistors and ensures a logic high output level when the inputs are open or shorted. This guar-antees that the receiver outputs are in a known state before communication begins and when communication ceases. FUNCTIONAL BLOCK DIAGRAMS

GND

Figure 1.

Figure 2.

GND

Figure 3.

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

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TABLE OF CONTENTS

Features .............................................................................................. 1 Applications ....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagrams ............................................................. 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 4 Timing Specifications—ADM 3070E/ADM 3071E/ADM 3072E ....................................... 5 Timing Specifications—ADM 3073E/ADM 3074E/ADM 3075E ....................................... 6 Timing Specifications—ADM 3076E/ADM 3077E/ADM 3078E ....................................... 7 Absolute Maximum Ratings ............................................................ 8 ESD Caution .................................................................................. 8 Pin Configurations and Function Descriptions ........................... 9 Test Circuits and Switching Characteristics .. (10)

Typical Performance Characteristics ........................................... 12 Circuit Description......................................................................... 15 Function Tables ........................................................................... 15 Receiver Fail-Safe ....................................................................... 15 Hot-Swap Capability .................................................................. 16 Line Length vs. Data Rate ......................................................... 16 ±15 kV ESD Protection ............................................................. 16 Human Body Model .................................................................. 16 256 Transceivers on the Bus ...................................................... 16 Reduced EMI and Reflections .................................................. 16 Low Power Shutdown Mode ..................................................... 17 Driver Output Protection .......................................................... 17 Typical Applications ................................................................... 17 Outline Dimensions ....................................................................... 19 Ordering Guide .. (20)

REVISION HISTORY

8/09—Rev. D to Rev. E

Changes to Ordering Guide .......................................................... 20 4/09—Rev. C to Rev. D

Changes to Ordering Guide .......................................................... 20 1/09—Rev. B to Rev. C

Changes to Ordering Guide .......................................................... 20 8/08—Rev. A to Rev. B

Changes to Table 3 ............................................................................ 5 Changes to Figure 36 ...................................................................... 18 Updated Outline Dimensions ....................................................... 19 Changes to Ordering Guide .......................................................... 20 10/06—Rev. 0 to Rev. A

Added ADM3077E and ADM3078E ............................... U niversal Changes to Figure 2 and Figure 3 ................................................... 1 Changes to Figure 5 and Figure 6 ................................................... 9 Changes to Figure 34 and Figure 35 ............................................. 17 Updated Outline Dimensions ....................................................... 19 Changes to Ordering Guide .......................................................... 20 8/06—Revision 0: Initial Version

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

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The driver outputs of the 250 kbps and 500 kbps devices are slew rate limited to reduce EMI and data errors caused by reflections from improperly terminated buses. Excessive power dissipation caused by bus contention or by output shorting is prevented with a thermal shutdown circuit. The parts are fully specified over the industrial temperature ranges and are available in 8-lead and 14-lead narrow SOIC packages.

Table 1. Selection Table

Part No. Half/Full

Duplex Data Rate (Mbps) Slew Rate Limited Driver/Receiver Enable Low Power Shutdown Nodes on Bus ±15 kV ESD on Bus Pins Pin Count ADM3070E Full 0.25 Yes Yes Yes 256 Yes 14 ADM3071E Full 0.25 Yes No No 256 Yes 8 ADM3072E Half 0.25 Yes Yes Yes 256 Yes 8 ADM3073E Full 0.5 Yes Yes Yes 256 Yes 14 ADM3074E Full 0.5 Yes No No 256 Yes 8 ADM3075E Half 0.5 Yes Yes Yes 256 Yes 8 ADM3076E Full 16 No Yes Yes 256 Yes 14 ADM3077E Full 16 No No No 256 Yes 8 ADM3078E Half

Yes Yes 256 Yes 8

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

SPECIFICATIONS

V CC = 3.3 V ± 10%, T A = T MIN to T MAX, unless otherwise noted.

1 Δ|V OD| and Δ|V OC| are the changes in V OD and V OC, respectively, when the DI input changes state.

Rev. E | Page 4 of 20

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

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TIMING SPECIFICATIONS—ADM3070E/ADM3071E/ADM3072E

V CC = 3.3 V ± 10%, T A = T MIN to T MAX , unless otherwise noted. Table 3.

Parameter Symbol Min Typ Max Unit Test Conditions/Comments DRIVER Maximum Data Rate 250 kbps Propagation Delay, Low-to-High Level t DPLH 250 1500 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Propagation Delay, High-to-Low Level t DPHL 250 1500 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Rise Time/Fall Time t DR /t DF 350 1600 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) |t DPLH ? t DPHL | Differential Driver Output Skew t DSKEW 200 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9)1 Enable to Output High t DZH 2500 ns See Figure 10 Enable to Output Low t DZL 2500 ns See Figure 11 Disable Time from Low t DLZ 100 ns See Figure 11 Disable Time from High t DHZ 100 ns See Figure 10 Enable Time from Shutdown to High t DZH(SHDN) 5500 ns See Figure 10 Enable Time from Shutdown to Low t DZL(SHDN) 5500 ns See Figure 11 RECEIVER Maximum Data Rate 250 kbps Propagation Delay, Low-to-High Level t RPLH 200 ns C L = 15 pF (see Figure 12 and Figure 13) Propagation Delay, High-to-Low Level t RPHL 200 ns C L = 15 pF (see Figure 12 and Figure 13) |t RPLH ? t RPHL | Output Skew t RSKEW 30 ns C L = 15 pF (see Figure 12 and Figure 13) Enable to Output High t RZH 50 ns See Figure 14 Enable to Output Low t RZL 50 ns See Figure 14 Disable Time from Low t RLZ 50 ns See Figure 14 Disable Time from High t RHZ 50 ns See Figure 14 Enable Time from Shutdown to High t RZH(SHDN) 4000 ns See Figure 14 Enable Time from Shutdown to Low t RZL(SHDN) 4000 ns See Figure 14 TIME TO SHUTDOWN t SHDN 50 200 600 ns

V CC = 3.3 V.

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

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TIMING SPECIFICATIONS—ADM3073E/ADM3074E/ADM3075E

V CC = 3.3 V ± 10%, T A = T MIN to T MAX , unless otherwise noted. Table 4.

Parameter Symbol Min Typ Max Unit Test Conditions/Comments DRIVER Maximum Data Rate 500 kbps Propagation Delay, Low-to-High Level t DPLH 180 800 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Propagation Delay, High-to-Low Level t DPHL 180 800 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Rise Time/Fall Time t DR /t DF 200 800 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) |t DPLH ? t DPHL | Differential Driver Output Skew t DSKEW 100 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Enable to Output High t DZH 2500 ns See Figure 10 Enable to Output Low t DZL 2500 ns See Figure 11 Disable Time from Low t DLZ 100 ns See Figure 11 Disable Time from High t DHZ 100 ns See Figure 10 Enable Time from Shutdown to High t DZH(SHDN) 4500 ns See Figure 10 Enable Time from Shutdown to Low t DZL(SHDN) 4500 ns See Figure 11 RECEIVER Maximum Data Rate 500 kbps Propagation Delay, Low-to-High Level t RPLH 200 ns C L = 15 pF (see Figure 12 and Figure 13) Propagation Delay, High-to-Low Level t RPHL 200 ns C L = 15 pF (see Figure 12 and Figure 13) |t RPLH ? t RPHL | Output Skew t RSKEW 30 ns C L = 15 pF (see Figure 12 and Figure 13) Enable to Output High t RZH 50 ns See Figure 14 Enable to Output Low t RZL 50 ns See Figure 14 Disable Time from Low t RLZ 50 ns See Figure 14 Disable Time from High t RHZ 50 ns See Figure 14 Enable Time from Shutdown to High t RZH(SHDN) 4000 ns See Figure 14 Enable Time from Shutdown to Low t RZL(SHDN) 4000 ns See Figure 14 TIME TO SHUTDOWN t SHDN 50 200 600 ns

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 7 of 20

TIMING SPECIFICATIONS—ADM3076E/ADM3077E/ADM3078E

V CC = 3.3 V ± 10%, T A = T MIN to T MAX , unless otherwise noted. Table 5.

Parameter Symbol Min Typ Max Unit Test Conditions/Comments DRIVER Maximum Data Rate 16 Mbps Propagation Delay, Low-to-High Level t DPLH 50 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Propagation Delay, High-to-Low Level t DPHL 50 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Rise Time/Fall Time t DR /t DF 15 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) |t DPLH ? t DPHL | Differential Driver Output Skew t DSKEW 8 ns C L = 50 pF, R L = 54 Ω (see Figure 8 and Figure 9) Enable to Output High t DZH 150 ns See Figure 10 Enable to Output Low t DZL 150 ns See Figure 11 Disable Time from Low t DLZ 100 ns See Figure 11 Disable Time from High t DHZ 100 ns See Figure 10 Enable Time from Shutdown to High t DZH(SHDN) 1250 1800 ns See Figure 10 Enable Time from Shutdown to Low t DZL(SHDN) 1250 1800 ns See Figure 11 RECEIVER Maximum Data Rate 16 Mbps Propagation Delay, Low-to-High Level t RPLH 40 75 ns C L = 15 pF (see Figure 12 and Figure 13) Propagation Delay, High-to-Low Level t RPHL 40 75 ns C L = 15 pF (see Figure 12 and Figure 13) |t RPLH ? t RPHL | Output Skew t RSKEW 8 ns C L = 15 pF (see Figure 12 and Figure 13) Enable to Output High t RZH 50 ns See Figure 14 Enable to Output Low t RZL 50 ns See Figure 14 Disable Time from Low t RLZ 50 ns See Figure 14 Disable Time from High t RHZ 50 ns See Figure 14 Enable Time from Shutdown to High t RZH(SHDN) 1800 ns See Figure 14 Enable Time from Shutdown to Low t RZL(SHDN) 1800 ns See Figure 14 TIME TO SHUTDOWN t SHDN 50 200 600 ns

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 8 of 20

ABSOLUTE MAXIMUM RATINGS

T A = 25°C, unless otherwise noted.

Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any

other conditions above those indicated in the operational

section of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods may affect

device reliability.

ESD CAUTION

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 9 of 20

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

RO RE DE V CC

NC A B DI Z GND Y GND NC

NC = NO CONNECT

06285-004

V CC RO DI GND

06285-005

RO RE DE DI CC 06285-006

Figure 4. ADM3070E/ADM3073E/ADM3076E

Pin Configuration

Figure 5. ADM3071E/ADM3074E/ADM3077E

Pin Configuration Figure 6. ADM3072E/ADM3075E/ADM3078E

Pin Configuration

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 10 of 20

TEST CIRCUITS AND SWITCHING CHARACTERISTICS

06285-007

Figure 7. Driver DC Test Load

06285-008

Figure 8. Driver Timing Test Circuit V CC

DI Z

+V O

–V O

V DIFF t DSKEW = |t DPLH –t DPHL |

06285-009

Figure 9. Driver Propagation Delays OUT

OUT

V CC

V OH

06285-010

Figure 10. Driver Enable and Disable Times (t DHZ , t DZH , t DZH(SHDN)) OUT

V CC

OUT

V CC

V CC 0V

06285-011

Figure 11. Driver Enable and Disable Times (t DZL , t DLZ , t DZL(SHDN))

06285-012

Figure 12. Receiver Propagation Delay Test Circuit

NOTES

1. THE RISE TIME AND FALL TIME OF INPUT A AND INPUT B < 4ns.

06285-013

Figure 13. Receiver Propagation Delays

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 11 of 20

)/2

V CC

V OL

V CC

V OL

V OH

V OH 0V

S1 CLOSED S2 OPEN S1 OPEN S2 CLOSED S1 CLOSED S2 OPEN S1 OPEN S2 CLOSED RE

06285-014

Figure 14. Receiver Enable and Disable Times

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 12 of 20

TYPICAL PERFORMANCE CHARACTERISTICS

06285-020

1.20.5–40

TEMPERATURE (°C)S U P P L Y C U R R E N T (m A )

–102050

801.11.00.90.80.70.611006285-023

3.30

3.00

–50

125

TEMPERATURE (°C)

O U T P U T H I G H V O L T A G E (V )

3.25

3.20

3.15

3.10

3.05

–250255075100Figure 15. Supply Current vs. Temperature

Figure 18. Receiver Output High Voltage vs. Temperature

06285-021

03OUTPUT HIGH VOLTAGE (V).506285-024

0.70–50

125

TEMPERATURE (°C)

O U T P U T L O W V O L T A G E (V )

0.6

0.50.40.30.2

0.1–2502550751000.5 1.0 1.5 2.0

2.5

3.0–180

O U T P U T C U R R E N T (m A )

–16

–14

–12–10–8–6–4–2

Figure 16. Output Current vs. Receiver Output High Voltage

Figure 19. Receiver Output Low Voltage vs. Temperature

06285-022

003OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )

.506285-025

1000

03DIFFERENTIAL OUTPUT VOLTAGE (V)

O U T P U T C U R R E N T (m A )

0.5 1.0 1.5 2.0

2.5

3.02015

0.5 1.0 1.5 2.0 2.5

3.090

70605040302010

Figure 17. Output Current vs. Receiver Output Low Voltage Figure 20. Driver Output Current vs. Differential Output Voltage

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

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06285-026

2.6

1.6–50

125

TEMPERATURE (°C)D I F F E R E N T I A L O U T P U T V O L T A G E (V )

–250255075100

2.5

2.4

2.32.22.12.01.91.81.7

Figure 21. Driver Differential Output Voltage vs. Temperature

06285-027

OUTPUT HIGH VOLTAGE (V)

O U T P U T C U R R E N T (m A

)

020406080100120

Figure 22. Output Current vs. Driver Output High Voltage

06285-028

OUTPUT LOW VOLTAGE (V)

O U T P U T C U R R E N T (m A

)

100

120

Figure 23. Output Current vs. Driver Output Low Voltage

06285-0290.90–50

125

TEMPERATURE (°C)

S H U T D O W N C U R R E N T (μA )

–250255075

1000.8

0.70.60.50.40.30.20.1

Figure 24. Shutdown Current vs. Temperature

06285-030

TEMPERATURE (°C)

P R O P A G A T I O N D E L A Y (n s )

200

400

600

800

1000

1200

Figure 25. ADM3070E/ADM3071E/ADM3072E Driver Propagation Delay vs. Temperature (250 kbps)

06285-031TEMPERATURE (°C)

P R O P A G A T I O N D E L A Y (n s )

100200300400500600

700

Figure 26. ADM3073E/ADM3074E/ADM3075E Driver Propagation Delay vs. Temperature (500 kbps)

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 14 of 20

06285-036

CH3 2.0V 8ns/pt MATH1 2.01V 400ns

M400s 125MS/s A CH2 1.24V

06285-032

0–50

125

TEMPERATURE (°C)

P R O P A G A T I O N D E L A Y (n s )

252015105–250255075100t DPLH

t DPHL

Figure 30. ADM3073E/ADM3074E/ADM3075E Driver

Propagation Delay (500 kbps)

Figure 27. ADM3076E/ADM3077E/ADM3078E Driver Propagation Delay vs. Temperature (16 Mbps)

06285-037

CH3 2.0V IT 400ps/pt MATH1 1.0V 20ns

M20ns 1.25GS/s A CH3 1.64V

06285-033

700–50

125

TEMPERATURE (°C)

P R O P A G A T I O N D E

L A Y (n s )

5040302010–250255075100

Figure 31. ADM3076E/ADM3077E/ADM3078E Driver

Propagation Delay (16 Mbps)

Figure 28. Receiver Propagation Delay vs. Temperature

06285-035

CH3 2.0V 4ns/pt MATH1 2.01V 200ns

M200ns 250MS/s A CH2 1.24V

06285-034

CH3 2.0V 20ns/pt MATH1 2.01V 1.0μs

M1.0μs 50MS/s A CH2 1.24V

Figure 32. Receiver Propagation Delay

Figure 29. ADM3070E/ADM3071E/ADM3072E Driver

Propagation Delay (250 kbps)

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 15 of 20

CIRCUIT DESCRIPTION

The ADM307xE series are high speed transceivers for RS-485 and RS-422 communications. Each device contains one driver and one receiver. All devices feature fail-safe circuitry, which guarantees a logic high receiver output when the receiver inputs are open or shorted or when they are connected to a terminated transmission line with all drivers disabled (see the Receiver Fail-Safe section). The ADM307xE also feature a hot-swap capability, allowing line insertion without erroneous data transfer (see the Hot-Swap Capability section). The ADM3070E/ADM3071E/ ADM3072E feature reduced slew rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing for error-free data transmission at rates up to 250 kbps.

The ADM3073E/ADM3074E/ADM3075E also offer slew rate limits, allowing transmit speeds up to 500 kbps. The ADM3076E/ ADM3077E/ADM3078E driver slew rates are not limited, making possible transmit speeds of up to 16 Mbps. The ADM3072E/ ADM3075E/ADM3078E are half-duplex transceivers; the ADM3070E/ADM3071E/ADM3073E/ADM3074E/ADM3076E/ ADM3077E are each full-duplex transceivers. All devices operate from a single 3.3 V supply. Drivers are output short-circuit current limited, and thermal shutdown circuitry protects drivers against excessive power dissipation. When activated, the thermal shutdown circuitry places the driver outputs into a high impedance state.

FUNCTION TABLES

ADM3070E/ADM3073E/ADM3076E

X = don't care.

High-Z = high impedance.

1 X = don't care. 2

High-Z = high impedance. ADM3071E/ADM3074E/ADM3077E

Table 10. Transmitting Truth Table

Transmitting Input Transmitting Outputs DI Y Z 1 1 0 0 0 1

Table 11. Receiving Truth Table

Receiving Input

Receiving Output

A ?

B RO ≥ ?50 mV 1 ≤ ?200 mV 0

Open/shorted 1

ADM3072E/ADM3075E/ADM3078E

1 X = don't care.

High-Z = high impedance.

1 X = don't care.

High-Z = high impedance.

RECEIVER FAIL-SAFE

The ADM307xE family guarantees a logic high receiver output when the receiver inputs are shorted, open, or connected to a terminated transmission line with all drivers disabled. This is done by setting the receiver input threshold between ?50 mV and ?200 mV . If the differential receiver input voltage (A ? B)

is greater than or equal to ?50 mV , RO is logic high. If A ? B

is less than or equal to ?200 mV , RO is logic low. In the case

of a terminated bus with all transmitters disabled, the receiver

differential input voltage is pulled to 0 V by the termination. With the receiver thresholds of the ADM307xE family, this results in a logic high with a 50 mV minimum noise margin.

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

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HOT-SWAP CAPABILITY

(ALL EXCEPT ADM3071E/ADM3074E/ADM3077E)

Hot-Swap Inputs

When a circuit board is inserted into a hot (or powered) back-plane, differential disturbances to the data bus can lead to data errors. During this period, processor logic output drivers are high impedance and are unable to drive the DE and RE inputs of the RS-485 transceivers to a defined logic level. Leakage currents up to ±10 μA from the high impedance state of the processor logic drivers can cause standard CMOS enable inputs of a tran-sceiver to drift to an incorrect logic level. Additionally, parasitic circuit board capacitance can cause coupling of V CC or GND to the enable inputs. Without the hot-swap capability, these factors can improperly enable the driver or receiver of the transceiver. When V CC rises, an internal pull-down circuit holds DE low and RE high. After the initial power-up sequence, the pull-down circuit becomes transparent, resetting the hot-swap tolerable input.

LINE LENGTH vs. DATA RATE

The RS-485/RS-422 standard covers line lengths up to 4000 feet. For line lengths greater than 4000 feet, Figure 37 illustrates an example line repeater.

±15 kV ESD PROTECTION

Two coupling methods are used for ESD testing: contact discharge and air-gap discharge. Contact discharge calls for a direct connection to the unit being tested. Air-gap discharge uses a higher test voltage but does not make direct contact with the test unit. With air-gap discharge, the discharge gun is moved toward the unit under test, developing an arc across the air gap, thus the term air-gap discharge. This method is influenced by humidity, temperature, barometric pressure, distance, and rate of closure of the discharge gun. The contact discharge method, while less realistic, is more repeatable and is gaining acceptance and preference over the air-gap method.

Although very little energy is contained within an ESD pulse, the extremely fast rise time, coupled with high voltages, can cause failures in unprotected semiconductors. Catastrophic destruc-tion can occur immediately as a result of arcing or heating. Even if catastrophic failure does not occur immediately, the device can suffer from parametric degradation that can result in degraded performance. The cumulative effects of continuous exposure can eventually lead to complete failure.

Input/output lines are particularly vulnerable to ESD damage. Simply touching or connecting an input/output cable can result in a static discharge that damages or completely destroys the interface product connected to the input/output port. It is extremely important, therefore, to have high levels of ESD protection on the input/output lines.

The ESD discharge can induce latch-up in the device under test, so it is important that ESD testing on the input/output pins be

carried out while device power is applied. This type of testing is more representative of a real-world input/output discharge, which occurs when equipment is operating normally. The transmitter outputs and receiver inputs of the ADM307xE family are characterized for protection to a ±15 kV limit using the human body model.

HUMAN BODY MODEL

Figure 33 shows the human body model and the current waveform it generates when discharged into low impedance. This model consists of a 100 pF capacitor charged to the ESD voltage of interest, which is then discharged into the test device through a 1.5 kΩ resistor.

06285-015

Figure 33. Human Body Model and Current Waveform

256 TRANSCEIVERS ON THE BUS

The standard RS-485 receiver input impedance is 12 kΩ (1 unit load), and the standard driver can drive up to 32 unit loads. The ADM307xE family of transceivers has a ? unit load receiver input impedance (96 kΩ), allowing up to 256 transceivers to be connected in parallel on one communication line. Any combi-nation of these devices and other RS-485 transceivers with a total of 32 unit loads or fewer can be connected to the line.

REDUCED EMI AND REFLECTIONS

The ADM3070E/ADM3071E/ADM3072E feature reduced slew rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing for error- free data transmission at rates up to 250 kbps. The ADM3073E/ ADM3074E/ADM3075E offer higher driver output slew rate limits, allowing for transmit speeds of up to 500 kbps.

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 17 of 20

LOW POWER SHUTDOWN MODE

(ALL EXCEPT ADM3071E/ADM3074E/ADM3077E)

Low power shutdown mode is initiated by bringing both RE high and DE low. In shutdown mode, the device draws less than 1 μA of supply current. RE and DE can be driven simulta-neously, but the parts are guaranteed not to enter shutdown if RE is high and DE is low for fewer than 50 ns. If the inputs are in this state for 600 ns or more, the parts are guaranteed to enter shutdown. Enable times t ZH and t ZL assume that the part was not originally in a low power shutdown state (see the section). Enable times (t ZH(SHDN) and t ZL(SHDN)) assume that the part was originally shut down. It takes drivers and receivers longer to become enabled from low power shutdown mode (t ZH(SHDN), t ZL(SHDN)) than from driver/ receiver disable mode (t ZH , t ZL ).

Test Circuits and Switching Characteristics DRIVER OUTPUT PROTECTION

The ADM307xE family features two methods to prevent excessive output current and power dissipation caused by faults or by bus contention. Current limit protection on the output stage provides immediate protection against short circuits over the whole common-mode voltage range (see Figure 22 and Figure 23). In addition, a thermal shutdown circuit forces the driver outputs into a high impedance state if the die temperature rises excessively.

TYPICAL APPLICATIONS

The ADM3072E/ADM3075E/ADM3078E transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figure 34 shows a typical network

applications circuit. The ADM3071E/ADM3074E/ADM3077E transceivers are designed for point-to-point transmission lines (see Figure 35). The ADM3070E/ADM3073E/ADM3076E transceivers are designed for full-duplex RS-485 networks (see Figure 36).

To minimize reflections, terminate the line at both ends with a termination resistor (the value of the termination resistor should be equal to the characteristic impedance of the cable used) and keep stub lengths off the main line as short as possible.

06285-016

NOTES

1. MAXIMUM NUMBER OF NODES: 256.

2. R T IS EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE CABLE USED.

Figure 34. ADM3072E/ADM3075E/ADM3078E Typical Half-Duplex RS-485 Network

06285-017

Figure 35. ADM3071E/ADM3074E/ADM3077E Full-Duplex Point-to-Point Applications

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 18 of 20

NOTES

1. MAXIMUM NUMBER OF NODES: 256.

2. R T IS EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE CABLE USED.

DE SLAVE

MASTER

06285-019

Figure 36. ADM3070E/ADM3073E/ADM3076E Full-Duplex RS-485 Network

DATA IN

DATA OUT

NOTES

1. R T IS EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE CABLE USED.

06285-018

Figure 37. Line Repeater for ADM3070E/ADM3073E/ADM3076E

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 19 of 20

OUTLINE DIMENSIONS

CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES)ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.

COMPLIANT TO JEDEC STANDARDS MS-012-AA

012407-A

0.17 (0.0067)

0.40 (0.0157)

PLANE

0.25 (0.0098)0.10 (0.0040)COPLANARITY

0.10

Figure 38. 8-Lead Standard Small Outline Package [SOIC_N]

Narrow Body

(R-8)

Dimensions shown in millimeters and (inches)

CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES)ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.

COMPLIANT TO JEDEC STANDARDS MS-012-AB

060606-A

BSC

0.31 (0.0122)

Figure 39. 14-Lead Standard Small Outline Package [SOIC_N]

Narrow Body (R-14)

Dimensions shown in millimeters and (inches)

ADM3070E/ADM3071E/ADM3072E/ADM3073E/ADM3074E/ADM3075E/ADM3076E/ADM3077E/ADM3078E

Rev. E | Page 20 of 20

ORDERING GUIDE

Model

Temperature

Range Package Description Package

Option Ordering Quantity ADM3070EARZ 1

?40°C to +85°C 14-Lead Standard Small Outline Package (SOIC_N) R-14

ADM3070EARZ-REEL71 ?40°C to +85°C 14-Lead Standard Small Outline Package (SOIC_N) R-14 1,000 ADM3070EYRZ 1

?40°C to +125°C 14-Lead Standard Small Outline Package (SOIC_N) R-14

ADM3070EYRZ-REEL71 ?40°C to +125°C 14-Lead Standard Small Outline Package (SOIC_N) R-14 1,000 ADM3071EARZ 1

?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3071EARZ-REEL71 ?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3071EYRZ 1

?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3071EYRZ-REEL71 ?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3072EARZ 1

?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3072EARZ-REEL71 ?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3072EYRZ 1

?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3072EYRZ-REEL71 ?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3073EARZ 1

?40°C to +85°C 14-Lead Standard Small Outline Package (SOIC_N) R-14

ADM3073EARZ-REEL71 ?40°C to +85°C 14-Lead Standard Small Outline Package (SOIC_N) R-14 1,000 ADM3073EYRZ 1

?40°C to +125°C 14-Lead Standard Small Outline Package (SOIC_N) R-14

ADM3073EYRZ-REEL71 ?40°C to +125°C 14-Lead Standard Small Outline Package (SOIC_N) R-14 1,000 ADM3074EARZ 1

?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3074EARZ-REEL71 ?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3074EYRZ 1

?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3074EYRZ-REEL71 ?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3075EARZ 1

?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3075EARZ-REEL71 ?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3075EWYRZ 1 ?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3075EWYRZ-RL71 ?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3075EYRZ 1

?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3075EYRZ-REEL71 ?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3076EARZ 1

?40°C to +85°C 14-Lead Standard Small Outline Package (SOIC_N) R-14

ADM3076EARZ-REEL71 ?40°C to +85°C 14-Lead Standard Small Outline Package (SOIC_N) R-14 1,000 ADM3076EYRZ 1

?40°C to +125°C 14-Lead Standard Small Outline Package (SOIC_N) R-14

ADM3076EYRZ-REEL71 ?40°C to +125°C 14-Lead Standard Small Outline Package (SOIC_N) R-14 1,000 ADM3077EARZ 1

?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3077EARZ-REEL71 ?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3077EYRZ 1

?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3077EYRZ-REEL71 ?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3078EARZ 1

?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3078EARZ-REEL71 ?40°C to +85°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000 ADM3078EYRZ 1

?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8

ADM3078EYRZ-REEL71

?40°C to +125°C 8-Lead Standard Small Outline Package (SOIC_N) R-8 1,000

Z = RoHS Compliant Part.