Rad Tolerant 3.3-V CAN Transceivers for Satellite Communications

Intersil Corp. recently announced  the industry’s first radiation-tolerant, 3.3-V controller area network (CAN) transceivers that are fully QML-V qualified and compliant with the ISO11898-2 physical layer standard. The three new ISL7202xSEH CAN transceivers provide reliable serial data transmission between a CAN controller and CAN bus at speeds up to 1 Mbps. Up to 120 of Intersil’s ISL7202xSEH transceivers can be connected to a single CAN bus to reduce cabling/harness size, weight and power (SWAP) costs. This weight and mass reduction of up to 18% allows system engineers to add millions of dollars in satellite functionality, and eliminate the extra cabling and tradeoffs associated with current point-to-point interface solutions.isl7202 Intersil

The ISL72026SEH, ISL72027SEH, and ISL72028SEH 3.3-V CAN transceivers deliver ultra-high performance in the most demanding environments by leveraging Intersil’s proprietary silicon on insulator process, which provides single event latch-up (SEL) and single event burn-out (SEB) robustness in heavy ion environments. With the emergence of all-electric propulsion satellites that maximize payload but take longer to reach final orbit, customers require higher total dose testing for mission assurance. Intersil’s CAN transceivers are low dose rate tested up to 75 krad on a wafer-by-wafer basis, and apply single event transient (SET) mitigation techniques to reduce system level bit error rates, providing predictable performance. They are also “cold spare” redundant capable, allowing the connection of additional unpowered transceivers to the CAN bus. This mission-critical capability maximizes system life.

  • The ISL7202xSEH family offers a number of unique features:
  • The ISL72026SEH includes a loopback test capability that allows node diagnostics and reporting while the system is transmitting data

It offers split termination output using the VREF pin to provide a VCC/2 output reference. This improves network electromagnetic compatibility and stabilizes the bus voltage, preventing it from drifting to a high common-mode voltage during inactive periods. The ISL72028SEH includes a low power shutdown mode that switches off the driver and receiver to draw 50 µA for power conservation.

Key features and specs:

  • Electrically screened to SMD 5962-15228, and compatible with ISO11898-2
  • Delivers 4-kV human body model (HBM) ESD protection on all pins
  • 3- to 3.6-V supply range, –7 to 12 V common-mode input voltage range, 5-V tolerant logic inputs, and bus pin fault protection to ±20-V terrestrial and ±18 V in orbit
  • Cold spare powered down devices do not affect active devices operating in parallel
  • Three selectable driver rise and fall times
  • Glitch free bus I/O during power-up and power-down
  • Full fail-safe receiver: open, short, terminated/undriven
  • Hi Z input allows for 120 nodes on the bus and data rates up to 1 Mbps
  • Low quiescent supply current of 7 mA
  • Thermal shutdown
  • Low dose rate (0.01 rad(Si)/s) radiation tolerance of 75 krad(Si)
  • SEL/B immune up to LET 60 MeV.cm2/mg

The ISL72026SEH, ISL72027SEH and ISL72028SEH 3.3V CAN transceivers are available in eight-lead ceramic flatpack packages.

Source: Intersil Corp.

CAN Flexible Data-Rate Transceiver Family

Microchip Technology recently launched the MCP2561/2FD family of CAN Flexible Data-Rate (FD) transceivers. As an interface between a CAN controller and the physical two-wire CAN bus, the transceivers work for both the CAN and CAN FD protocols. Thus, the family helps automotive and industrial manufacturers with current CAN communication needs and provides a path for newer CAN FD networks.Microchip MCP25612FD CAN FD transceivers

In-vehicle networking growth continues to be driven by the need for electronic monitoring and control. As application features in power train, body and convenience, diagnostics and safety increase, more Electronic Control Units (ECUs) are being added to existing CAN buses, causing automotive OEMs to become bandwidth limited. In addition, the end-of-line programming time for ECUs is on the rise due to more complex application programs and calibration, which raises production line costs. The emerging CAN FD bus protocol solves these issues by increasing the maximum data rate while expanding the data field from 8 data bytes up to 64 data bytes.

With their robustness and industry-leading features, including data rates of up to 8 Mbps, Microchip’s MCP2561/2FD transceivers enable customers to implement and realize the benefits of CAN FD. These new transceivers have one of the industry’s lowest standby current consumption (less than 5 µA typical), helping meet ECU low-power budget requirements. Additionally, these devices support operation in the –40°C to 150°C temperature range, enabling usage in harsh environments.

The new family of MCP2561/2FD CAN FD transceivers is available in eight-pin PDIP, SOIC and 3 × 3 mm DFN (leadless) packages, providing additional design flexibility for space-limited applications. The family also provides two options. The MCP2561FD comes in an 8-pin package and features a SPLIT pin. This SPLIT pin helps to stabilize the common mode in biased split-termination schemes. The MCP2562FD is available in an eight-pin package and features a Vio pin. This Vio pin can be tied to a secondary supply in order to internally level shift the digital I/Os for easy microcontroller interfacing. This is beneficial when a system is using a microcontroller at a VDD less than 5 V (e.g., 1.8 V or 3.3 V), and eliminates the need for an external level translator, decreasing system cost and complexity.

The MCP2561FD and MCP2562FD transceivers are both available now for sampling and volume production in 8-pin PDIP, SOIC and 3 × 3 mm DFN packages, starting at $0.69 each, in 5,000-unit quantities.

Source: Microchip Technology

3.3-V/5-V 4-Mbps CAN Transceiver

Linear Technology Corporation introduces the LTC2875, an exceptionally rugged, high-voltage-tolerant controller area network (CAN) transceiver to greatly reduce field failures without the need of costly external protection devices. In practical CAN systems, installation cross-wiring faults, ground voltage faults or lightning induced surge voltages can cause overvoltage conditions that exceed absolute maximum ratings of typical transceivers. The LTC2875 features ±60-V overvoltage fault and ±25-kV HBM ESD protection on the data transmission lines, protecting bus pins during operation and shutdown. Whether a circuit is transmitting, receiving or powered off, the LTC2875 tolerates any voltage within ±60 V without damage, increasing the robustness of typical CAN networks.Linear LTC2875

CAN bus systems are becoming increasingly popular in industrial controls, instrumentation networks and automotive electronics. The CAN bus has a well defined protocol stack, with support for standalone controllers, FPGAs and ASICs, making implementation easier over alternative interfaces, such as RS-485. The LTC2875 provides the flexibility to be powered from a 3.3-V or 5-V rail, which is very useful in industrial applications where a 5V rail may not be present. In addition to the high fault and ESD protection, the device features a low electromagnetic emission (EME) driver with a transmit data (TXD) dominant timer to prevent faulty controllers from clamping the bus, as well as a high electromagnetic immunity (EMI) receiver with an extended ±36-V common mode range to enable operation in electrically noisy environments and in the presence of ground loops. The LTC2875 features a high speed data rate of 4 Mbps with an adjustable slew rate for data rates as low as 1 kbps. A shutdown mode brings all of the LTC2875’s outputs to high impedance and reduces power consumption to 1 µA.

The LTC2875 is offered in commercial, industrial, automotive and military (–55°C to 125°C) temperature grades and is available in 3 mm × 3 mm DFN-8 and SO-8 packages, with industry-standard pinouts.

Pricing starts at $1.72 each in 1,000-piece quantities.

Source: Linear Technology

High-Speed Laser Range Finder Board with IMU


The NavRanger-OEM

The NavRanger-OEM combines a 20,000 samples per second laser range finder with a nine-axis inertial measurement unit (IMU) on a single 3“ × 6“ (7.7 × 15.3 cm) circuit board. The board features I/O resources and processing capability for application-specific control solutions.

The NavRanger‘s laser range finder measures the time of flight of a short light pulse from an IR laser. The time to digital converter has a 65-ps resolution (i.e., approximately 1 cm). The Class 1M laser has a 10-ns pulse width, a 0.8 mW average power, and a 9° × 25° divergence without optics. The detector comprises an avalanche photo diode with a two-point variable-gain amplifier and variable threshold digitizer. These features enable a 10-cm × 10-cm piece of white paper to be detected at 30 m with a laser collimator and 25-mm receiver optics.

The range finder includes I/O to build a robot or scan a solution. The wide range 9-to-28-V input supply voltage enables operation in 12- and 24-V battery environments. The NavRanger‘s IMU is an InvenSense nine-axis MPU-9150, which combines an accelerometer, a gyroscope, and a magnetometer on one chip. A 32-bit Freescale ColdFire MCF52255 microcontroller provides the processing the power and additional I/O. USB and CAN buses provide the board’s high-speed interfaces. The board also has connectors and power to mount a Digi International XBee wireless module and a TTL GPS.

The board comes with embedded software and a client application that runs on a Windows PC or Mac OS X. It also includes modifiable source code for the embedded and client applications. The NavRanger-OEM costs $495.

Integrated Knowledge Systems, Inc.

Scott Garman, Technical Evangelist

This article was a preview of an upcoming interview in the February issue of Circuit Cellar. The full interview is now available here.

Scott Garman is a Portland, OR-based Linux software engineer. Scott is very involved with the Yocto Project, an open-source collaboration that provides tools for the embedded Linux industry. Scott tells us about how he recently helped Intel launch MinnowBoard, the company’s first open-hardware SBC. The entire interview will be published in Circuit Cellar’s February issue.—Nan Price, Associate Editor

NAN: What is the Yocto Project?

 SCOTT: The Yocto Project is centered on the OpenEmbedded build system, which offers a tremendous amount of flexibility in how you can create embedded Linux distros. It gives you the ability to customize nearly every policy of your embedded Linux system.

I’ve developed training materials for new developers getting started with the Yocto Project, including “Getting Started with the Yocto Project—New Developer Screencast Tutorial.”


Scott was involved with a MinnowBoard robotics and computer vision demo at LinuxCon Japan, May 2013.

NAN: Tell us about Intel’s recently introduced the MinnowBoard SBC.

SCOTT: The MinnowBoard is based on Intel’s Queens Bay platform, which pairs a Tunnel Creek Atom CPU (the E640 running at 1 GHz) with the Topcliff Platform controller hub. The board has 1 GB of RAM and includes PCI Express, which powers our SATA disk support and gigabit Ethernet. It’s an SBC that’s well suited for embedded applications that can use that extra CPU and especially I/O performance.


Scott worked on a MinnowBoard demo built around an OWI Robotic Arm.

The MinnowBoard also has embedded bus standards including GPIO, I2C, SPI, and even CAN (used in automotive applications) support. We have an expansion connector on the board where we route these buses, as well as two lanes of PCI Express for custom high-speed I/O expansion.

NAN: What compelled Intel to make the MinnowBoard open hardware?

SCOTT: The main motivation for the MinnowBoard was to create an affordable Atom-based development platform for the Yocto Project. We also felt it was a great opportunity to try to release the board’s design as open hardware.