Exar, listed on Nasdaq as EXAR, has introduced a new high-performance component to its single-chip RS-232/RS-485/RS-422 multi-protocol serial transceiver family — the SP338. This latest addition enhances Exar’s existing portfolio and reinforces its leadership in the single-chip, multi-protocol transceiver market. The SP338 is particularly well-suited for industrial or embedded systems that require flexible serial communication interfaces.
In RS-232 mode, the SP338 provides three drivers and five receivers, supporting the eight signal channels needed for a DB9 connector (3TX/5RX). In RS-485/422 mode, it offers multiple configurations, including half-duplex, full-duplex, and hybrid duplex, with up to two drivers and four receivers (2TX/4RX), making it highly adaptable for various applications.
Jack Roan, Technology Marketing Manager at Exar Interface Product Line, highlighted the significance of the SP338 and its sibling, the SP339: "These two devices solve a major design challenge when sharing a single connector between different serial protocols. They allow for seamless enablement and disablement of termination resistors during protocol switching."
The SP338 integrates internal termination resistors and control switches, enabling the system processor to manage these resistors through a single pin. It also includes advanced features such as open-circuit, short-circuit, and Exar-enhanced receiver fail-safe modes, which eliminate the need for external resistor biasing networks and switching components when the bus is idle.
When using a shared connector between RS-232 and RS-485/422 protocols, the RS-485 termination and bias resistor must be disconnected for proper RS-232 communication. Traditionally, this required large and costly relays due to the wide common-mode voltage range (-7V to +12V) in RS-485. Designers often opted for separate connectors or manual resistor switching, increasing both cost and size. The SP338 eliminates these inefficiencies by integrating all necessary functions.
In addition to its built-in switchable termination resistors, the SP338 supports eight configurable modes, including diagnostic loopback, RS-232 (3TX/5RX), half-duplex RS-485, full-duplex RS-485/422, and hybrid duplex (2TX/4RX). It can switch between any mode via a single control pin, with a maximum transmission rate of 20 Mbps for RS-485/422 and 1 Mbps for RS-232. The device also features a slew rate of 256 kbps.
The SP338 includes an internal charge pump that generates the bipolar voltage levels required for RS-232 operation from a single 3.3V or 5V supply, using only four external capacitors. This eliminates the need for inductors or magnetic components, further reducing system complexity and cost.
All bus pins are protected against electrostatic discharge (ESD) with ratings up to ±15kV (Human Body Mode) and ±8kV IEC 61000-4-2 contact discharge, ensuring robust performance in harsh environments.
Microcomputer Integrated Measurement And Control Device
Measurement And Control Device,Microcomputer Protector,Bus Comprehensive Protection Measurement,Pt Parallel Device
zhejiangjinyidianqiyouxiangongsi , https://www.jooeei.com