ADM4850 AD [Analog Devices], ADM4850 Datasheet

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ADM4850

Manufacturer Part Number
ADM4850
Description
5 V Slew-Rate Limited Half- and Full-Duplex RS-485/RS-422 Transceivers
Manufacturer
AD [Analog Devices]
Datasheet

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FEATURES
EIA RS-485-/RS-422-compliant
Data rate options
Half- and full-duplex options
Reduced slew rates for low EMI
True fail-safe receiver inputs
5 µA (maximum) supply current in shutdown mode
Up to 256 transceivers on one bus
Outputs high-z when disabled or powered off
−7 V to +12 V bus common-mode range
Thermal shutdown and short-circuit protection
Pin-compatible with MAX308x
Specified over the −40°C to +85°C temperature range
Available in 8-lead SOIC and LFCSP packages
APPLICATIONS
Low power RS-485 applications
EMI-sensitive systems
DTE-DCE interfaces
Industrial control
Packet switching
Local area networks
Level translators
GENERAL DESCRIPTION
The ADM4850−ADM4857 are differential line transceivers
suitable for high speed half- and full-duplex data communication
on multipoint bus transmission lines. They are designed for
balanced data transmission and comply with EIA Standards
RS-485 and RS-422. The ADM4850−ADM4853 are half-duplex
transceivers, which share differential lines and have separate
enable inputs for the driver and receiver. The full-duplex
ADM4854−ADM4857 transceivers have dedicated differential
line driver outputs and receiver inputs.
The parts have a 1/8-unit-load receiver input impedance, which
allows up to 256 transceivers on one bus. Since only one driver
should be enabled at any time, the output of a disabled or pow-
ered-down driver is three-stated to avoid overloading the bus.
The receiver inputs have a true fail-safe feature, which ensures a
logic high output level when the inputs are open or shorted.
This guarantees that the receiver outputs are in a known state
before communication begins and when communication ends.
Rev. 0
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.
ADM4850/ADM4854—115 kbps
ADM4851/ADM4855—500 kbps
ADM4852/ADM4856—2.5 Mbps
ADM4853/ADM4857—10 Mbps
5 V Slew-Rate Limited Half- and Full-Duplex
The driver outputs 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 commercial and industrial
temperature ranges, and are available in 8-lead SOIC and LFCSP
packages.
Table 1. Selection Table
Part No
ADM4850
ADM4851
ADM4852
ADM4853
ADM4854
ADM4855
ADM4856
ADM4857
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703
RO
RE
DE
DI
RS-485/RS-422 Transceivers
ADM4850/ADM4851/
ADM4852/ADM4853
FUNCTIONAL BLOCK DIAGRAM
D
R
GND
V
CC
Half-/Full-Duplex
Half
Half
Half
Half
Full
Full
Full
Full
© 2004 Analog Devices, Inc. All rights reserved.
ADM4850–ADM4857
Figure 1.
A
B
RO
DI
ADM4854/ADM4855/
ADM4856/ADM4857
D
R
GND
www.analog.com
V
CC
Data Rate
115 kbps
500 kbps
2.5 Mbps
10 Mbps
115 kbp
500 kbps
2.5 Mbps
10 Mbps
A
B
Z
Y

Related parts for ADM4850

ADM4850 Summary of contents

Page 1

... They are designed for balanced data transmission and comply with EIA Standards RS-485 and RS-422. The ADM4850−ADM4853 are half-duplex transceivers, which share differential lines and have separate enable inputs for the driver and receiver. The full-duplex ADM4854− ...

Page 2

... ADM4850–ADM4857 TABLE OF CONTENTS Specifications..................................................................................... 3 ADM4850/ADM4854 Timing Specifications........................... 4 ADM4851/ADM4855 Timing Specifications........................... 4 ADM4852/ADM4856 Timing Specifications........................... 5 ADM4853/ADM4857 Timing Specifications........................... 5 Absolute Maximum Ratings............................................................ 6 ESD Caution.................................................................................. 6 Pin Configurations and Function Descriptions ........................... 7 Test Circuits....................................................................................... 8 Switching Characteristics ................................................................ 9 Typical Performance Characteristics ........................................... 10 REVISION HISTORY 10/04—Revision 0: Initial Version Circuit Description......................................................................... 12 Slew-Rate Control ...

Page 3

... Rev Page ADM4850–ADM4857 Unit Test Conditions/Comments R = ∞, Figure Ω (RS-422), Figure Ω (RS-485), Figure − Figure 5 TST Ω Ω, Figure Ω ...

Page 4

... 500 Ω 100 pF, Figure 7, ADM4850 L = 500 Ω pF, Figure 7, ADM4850 L = 500 Ω 100 pF, Figure 7, ADM4850 pF, Figure pF, Figure kΩ pF, Figure 9, ADM4850 kΩ pF, Figure 9, ADM4850 kΩ pF, Figure 9, ADM4850 Ω 100 pF, Figure Ω ...

Page 5

... 4000 330 3000 ns ADM4853 Rev Page ADM4850–ADM4857 = 54 Ω 100 pF, Figure Ω 100 pF, Figure Ω 100 pF, Figure 500 Ω 100 pF, Figure 7, ADM4852 L = 500 Ω pF, Figure 7, ADM4852 L =500 Ω ...

Page 6

... ADM4850–ADM4857 ABSOLUTE MAXIMUM RATINGS Table 7. Parameter V to GND CC Digital I/O Voltage (DE, RE, DI, ROUT) Driver Output/Receiver Input Voltage Operating Temperature Range Storage Temperature Range θ Thermal Impedance JA SOIC LFCSP Lead Temperature Soldering (10 s) Vapour Phase (60 s) Infrared (15 s) ESD CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection ...

Page 7

... TOP VIEW GND (Not to Scale) Figure 2. ADM4850–ADM4853 Pin Configuration Description Receiver Output. When enabled, if (A−B) ≥ −30 mV, then RO = high. If (A−B) ≤ −200 mV, then RO = low. Receiver Output Enable. A low level enables the receiver output, RO. A high level places high impedance state. ...

Page 8

... ADM4850–ADM4857 TEST CIRCUITS V OD Figure 4. Driver Voltage Measurement 375Ω V OD3 60Ω 375Ω Figure 5. Driver Voltage Measurement over Common-Mode Voltage Range A R LDIFF B Figure 6. Driver Propagation Delay TST Rev Page ...

Page 9

... PLH 1. SKEW PLH – Figure 11. Receiver Propagation Delay t PHL 90% POINT A, B 10% POINT PHL V OH 1.5V | PHL V OL Rev Page ADM4850–ADM4857 DE 1. 2.3V Figure 12. Driver Enable/Disable Timing 1. O/P LOW ...

Page 10

... ADM4850–ADM4857 TYPICAL PERFORMANCE CHARACTERISTICS 400 ADM4853 350 300 ADM4853 GND 250 200 ADM4850 150 100 ADM4850 GND 50 0 –50 – TEMPERATURE (°C) Figure 14. Unloaded Supply Current vs. Temperature 0.2 0.4 0.6 0.8 1.0 1.2 RECEIVER OUTPUT LOW VOLTAGE (V) Figure 15 ...

Page 11

... Figure 24. Driver/Receiver Propagation Delay (ADM4855, 500 kbps CH1 2.00VΩ CH3 1.00VΩ 100 125 Figure 25. Driver/ Receiver Propagation Delay (ADM4855, 4 Mbps) Rev Page ADM4850–ADM4857 ADM4855 ADM4853 – 100 125 TEMPERATURE (°C) B CH2 1.00VΩ ...

Page 12

... GND RECEIVER INPUT FILTERING The receivers of all the devices incorporate input hysteresis. In addition, the receivers of the 115 kbps ADM4850/ADM485 and the 500 kbps ADM4851/ADM4855 incorporate input filtering. This enhances noise immunity with differential signals that have very slow rise and fall times. However, it causes the propagation delay to increase by 20% ...

Page 13

... Note that only one driver should be enabled at a time, while many receivers can be enabled. SHUTDOWN MODE The ADM4850–ADM4853 have a low power shutdown mode, which is enabled by taking RE high and DE low. If shutdown mode is not used, the fact that DE is active high and RE is active low offers a convenient way of switching the device between transmit and receive by tying DE and RE together ...

Page 14

... ADM4850–ADM4857 OUTLINE DIMENSIONS 5.00 (0.1968) 4.80 (0.1890 6.20 (0.2440) 4.00 (0.1574) 5.80 (0.2284) 3.80 (0.1497 1.27 (0.0500) BSC 1.75 (0.0688) 1.35 (0.0532) 0.25 (0.0098) 0.10 (0.0040) 0.51 (0.0201) COPLANARITY 0.25 (0.0098) 0.31 (0.0122) SEATING 0.10 0.17 (0.0067) PLANE COMPLIANT TO JEDEC STANDARDS MS-012AA 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 Figure 28 ...

Page 15

... ADM4850ACP-REEL −40°C to +85°C ADM4850ACP-REEL7 −40°C to +85°C ADM4850AR −40°C to +85°C ADM4850AR-REEL −40°C to +85°C ADM4850AR-REEL7 −40°C to +85°C ADM4851ACP-REEL −40°C to +85°C ADM4851ACP-REEL7 −40°C to +85°C ADM4851AR −40°C to +85°C ADM4851AR-REEL − ...

Page 16

... ADM4850–ADM4857 NOTES © 2004 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D04931–0–10/04(0) Rev Page ...

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