Maxlinear Adds Serial Transceivers for Harsh Industrial Applications

Maxlinear recently introduced several new members to its MxL8323x family of serial transceivers. The MxL83232, MxL83233, MxL83234, MxL83235, and MxL83236 range in data rates from 500 kbps to 50 Mbps. The chips are half-duplex (one Tx and one Rx) RS-485/RS-422 transceivers. They meet or exceed TIA/EIA-485A requirements.

The MxL8323x. 

While Wi-Fi, Bluetooth, and Ethernet get most of the attention in communications, they are not suitable for many applications. The serial universal asynchronous receiver/transmitter (UART) is often the easiest and most reliable communications system for connecting smart industrial equipment. The RS-485/422 standard has been around for more than 40 years and continues to soldier on in industrial and harsh-environment applications. It is reliable, easy to implement in software, and suitable for use over simple shielded twisted-pair wire runs.

Designed for Industrial Operations

Industrial electronics live in an environment that can send shudders down an EE’s spine. Despite shielding, protection, and careful design, real-world industrial equipment faces harsh temperatures, electrical noise, and ESD hazards. Maxlinear designed these transceivers for such deployment environments.

They meet IEC 61000‑4‑4 and 61000-4-2 standards for electrical fast transient (EFT) and electrostatic discharge (ESD) tolerance. This equates to +/- 4-kV EFT events, +/- 8-kV contact ESD and +/- 15-kV air-gap ESD. The signals tolerate ±15 V of common‑mode voltage, and the chips operate over an industrial-grade temperature range of –40°C to +125 °C.

Server management application example. (Page 5 of the Maxlinear MxL brochure)

The parts offer system-voltage flexibility for a 3.0-V to 5.5-V supply and 1.65-V logic-level compatibility. The flexible voltage compatibility allows for use with common industrial electronics that may operate with either voltage supply. The 1.65-V logic level provides compatibility with a wider range of processors and improved operation in noisy environments or in circuits subject to voltage sag. Board space and BOM line-item count are reduced by eliminating the need for line-level translation circuitry that fixed-voltage transceivers often require.

Typical applications include factory automation, motor drives, HVAC systems, security, smart grid infrastructure, and portable IoT devices.

Key Features: MxL83232, 33, and 34

The MxL83232, 33, and 34 parts come in two IC package form factors—4.9 mm x 3.9 mm NSOIC8 or 3 mm x 3 mm MSOP8—allowing use in small devices or in multiples in higher-bus-capability systems. The MxL83235 and 36 variants come in a 3 mm x 3 mm MSOP10 package.

All variants feature fail-safe logic and deliver a logic-high output if inputs are open, shorted, or idle. They have short-circuit protection, thermal shutdown, and high impedance during operating and shutdown. The high impedance (at least 96 kΩ) is equivalent to 1/8 of a standard RS-485 receiver load.

While standard RS-485 devices can share up to 32 loads on the bus, the Maxlinear devices’ 1/8 load allows for up to 256 device nodes on bidirectional multipoint bus transmission lines. The transceivers are rated for RS-485/422-compliant cable lengths up to 4000 ft.

MxL83232/33/34 8-pin half duplex transceiver. (Page 1 of the Maxlinear MxL83232/33/34 datasheet)

Data rates for the three variants are as follows:

• MxL83232: 500kbps
• MxL83233: 20 Mbps
• MxL83234: 50 Mbps

MxL83235 and 36 Add Hot Swap and Slew Control

The MxL83235 and 36 add hot-swap capability and a slew-rate control pin to reduce EMI and drop data rates to 500 kbps when conditions require electrically quieter operation or when used with poorly terminated cables. These two parts also include a 1-µA, ultra-low-power shutdown mode.

MxL83235/36 10-pin half duplex transceiver. (Page 1 of the Maxlinear MxL83232/33/34 datasheet)

Data rates for the two variants are as follows:

• MxL83235: 20 Mbps
• MxL83236: 50 Mbps

Product Availability

Maxlinear is now selling sample quantities of individual components and evaluation boards on its website.

All images used courtesy of Maxlinear.