Transceiver integrates isolated power.
Share:
Press Release Summary:
Model LTM2881 isolated RS485 µModule® transceiver breaks ground loops by isolating logic level interface and line transceiver using internal inductive signal isolation, providing common mode rejection of greater than 30 kV/µS. Powered by low-EMI DC-DC converter, ±15 kV ESD-protected unit features 2,500 Vrms galvanic isolation, onboard secondary power, and thermal shutdown protection. Incorporating RS485 transmitter and receiver, it is available in 3.3 and 5 V input supply voltages.
Original Press Release:
Isolated RS485 µModule® Transceiver Integrates Isolated Power
MILPITAS, CA - August 31, 2009 - Linear Technology Corporation introduces the LTM2881, an isolated RS485 µModule® transceiver that guards against large ground-to-ground differentials and common mode transients. In practical RS485 systems, ground potentials vary widely from node to node, often exceeding the tolerable range, which can result in an interruption of communications or destruction of a transceiver. The LTM2881 breaks ground loops by isolating the logic level interface and line transceiver using internal inductive signal isolation that allows for a much larger common mode voltage range plus superior common mode rejection of >30kV/µS. A low EMI DC-DC converter powers the transceiver and provides an isolated 5V supply output for powering any supporting external components. With 2,500VRMS of galvanic isolation, onboard secondary power and a fully compliant RS485 transmitter and receiver, the LTM2881 requires no external components, ensuring a complete, small µModule solution for isolated serial data communications.
The features of the LTM2881 make it suitable for a wide range of applications, including breaking ground loops, working with large common mode voltages and when using multiple unterminated line taps. The ±15kV ESD-protected transceiver operates at 20Mbps or low EMI 250kbps, in half-duplex or full-duplex configurations. The driver maintains high impedance over the entire common mode range and has a short circuit current limit, as well as slew rate control for minimizing EMI. Its counterpart, the failsafe receiver, allows up to 256 devices to be connected on the same lines and defaults to a logic '1' if the receiver inputs are open, shorted or terminated but not driven, all without the need to pre-bias the network. Integrated selectable termination allows cables to be properly terminated to avoid signal reflections and distorted waveforms, with the flexibility to add or remove termination anywhere onto the bus via a software switch. The device also features thermal shutdown protection, disabling the transceiver outputs in case of excessive power dissipation. Users will appreciate how the self-powered LTM2881 takes many precautions to guarantee safe and reliable communications in RS485 or RS422 systems.
Two versions of the LTM2881 are available to support 3.3V and 5V input supply voltages. The LTM2881 is available in low profile 11.25 x 15mm x 2.8mm surface mount LGA and BGA packages. All integrated circuits and passive components are housed in this Linear Technology, RoHS-compliant µModule package. Pricing starts at $8.45 each in 1,000 piece quantities. Please visit www.linear.com for product selection information.
Summary of Features: LTM2881
Isolated RS485/RS422 Transceiver: 2500VRMS
Integrated Isolated Low EMI DC/DC Converter
No External Components Required
20Mbps or Low EMI 250kbps Data Rate
High ESD: ±15kV HBM on Transceiver Interface
High Common Mode Transient Immunity: 30kV/us
Integrated Selectable 120Ohm Termination
3.3V (LTM2881-3) or 5.0V (LTM2881-5) Nominal Supply Voltage Options
1.62V to 5.5V Logic Supply Pin for Flexible Digital Interface
Isolated Logic Monitor Channel
Small Footprint, Low Profile (11.25mm x 15mm x 2.8mm) Surface Mount LGA & BGA Packages
2.5kV Isolated RS485 Transceiver with Power
About Linear Technology
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits, was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major public companies in 2000. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, µModule® products, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
LT, LTC, LTM, µModule and are registered trademarks of Linear Technology Corp. All other trademarks are the property of their respective owners.
Worldwide Contacts
North America and General Information
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
Doug Dickinson
Tel: (408) 432 1900 ext. 2233
ddickinson@linear.com
China (PRC)
Fanny Lau
Tel: 852-2428-0303
flau@linear.com
Angela Ao
Tel: (8610)6522 8081
angela.ao@ebacomms.com
Japan
Kazuto Takahashi
Tel: 81-3-5226-7291
ktakahashi@linear.com
Hitoshi Kasai
Tel: +0422-47-5319
kasai@miacis.com
Germany
Ralf Stegmann
Tel: +49 (0) 7131 9234-11
ralf@ezwire.com
France
Clotilde Zeller
Tel: +33 1 4614 87 09
clotilde@ezwire.com
Italy
Simona Labianca
Tel: +39 340 0571697
simona@ezwire.com
UK & Nordic
Alan Timmins
Tel: +44-1252-629937
alan@ezwire.com
Korea
Desiree Park
Tel: +82-2-565-6625
desiree@ezwire.com
Taiwan
Alice Wang
Tel: + 886-2-28974705
alice@ezwire.com
