Dual Isolated RS232 µModule Transceiver Integrates Isolated Power
Linear Technology Corporation introduces the LTM2882, a 2-channel isolated RS232 µModule® transceiver that guards against large ground-to-ground differentials and common mode transients. In practical RS232 systems, ground potentials may vary widely from node to node, often exceeding the tolerable range, resulting in an interruption of communications or destruction of a transceiver. The LTM2882 breaks ground loops by isolating the logic level interface and line transceiver using internal inductive signal isolation. This allows for a much larger common mode voltage range plus superior common mode rejection >30kV/µs. A low EMI DC-DC converter generates the power supplies for driving RS232 levels and provides an additional isolated 5V supply output for powering any supporting external components. With 2,500VRMS of galvanic isolation, onboard secondary power and two fully compliant RS232 transmitters and receivers, the LTM2882 requires no external components, providing a complete, small µModule solution for isolated serial data communications.
The LTM2882 addresses a wide range of RS232 applications, including industrial communications and test/measurement equipment, where breaking ground loops or working with large common mode voltages is demanded. The ±10kV ESD-protected transceiver operates at up to 1Mbps and only consumes 30µA of shutdown current when disabled. The two drivers can be enabled and disabled in less than 2µs using the uncommitted auxiliary isolated digital channel and are protected from short-circuits to any voltage within the absolute maximum range of ±15V. Their receiver counterparts are protected from common mode voltages within the absolute maximum range of ±25V. The LTM2882 meets RF and magnetic field immunity test requirements per European standard EN 550024. Users will appreciate how the self-powered LTM2882 takes many precautions to guarantee safe and reliable communications in RS232 systems.
Two versions of the LTM2882 are available to support 3.3V and 5V input supply voltages. The LTM2882 is available in low profile 11.25 × 15mm × 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: LTM2882
- Isolator µModule Technology
- Isolated RS232 Transceiver: 2500VRMS
- Integrated Isolated DC/DC Converter: 1W, 65% Efficiency
- No External Components Required
- 1.62V to 5.5V Logic Supply for Flexible Digital Interface
- High Speed Operation
- 1Mbps for 250pF/3kΩ Load
- 250kbps for 1nF/3kΩ Load
- 100kbps for 2.5nF/3kΩ TIA/EIA-232-F Load
- 3.3V (LTM2882-3) or 5V (LTM2882-5) Operation
- No Damage or Latchup to ±10kV ESD HBM on Isolated RS232 Interface & Across Isolation Barrier
- High Common Mode Transient Immunity: 30kV/µs
- Common Mode Working Voltage: 560VPEAK
- True RS232 Compliant Output Levels
- Low Profile (15mm × 11.25mm × 2.8mm) Surface Mount LGA & BGA Packages
2.5kV Dual Isolated RS232 Transceiver with Power
Editor's Contact Information
- Doug Dickinson