Low-noise LDO regulator powers automotives and smart automation

For always-on automotive modules and noise-sensitive loads, the LDO40L 400mA low-dropout (LDO) linear regulator delivers quiet and efficient power, says STMicroelectronics.

The AEC-Q100 qualified LDO40L has 45 microA quiescent current and reduces the demand on vehicle batteries to run loads such as body and interior functions that are active when the ignition is off. The LDO40L can be disabled to achieve a very-low shutdown current of only one microA.

The internal circuity operates from an input voltage as low as 3.5V and combines with the extremely low dropout voltage of 36mV at 100mA load, or 140mV at full load. The LDO40L maintains power to the load as the input dips during cold cranking.

The LDO40L powers automotive body-control modules, instruments and clusters, and LED lighting, and ensures stable DC for industrial controls and building- or home-automation applications. Output noise is just 20 microV, power-supply rejection ratio (PSRR) 70dB at 1kHz, and protection features including current limit and thermal shutdown are built-in.

There is a choice of fixed 3.0, 3.3, 5.0 or 8.5V output voltage, regulated within ± three per cent including line, load and temperature variation. Only two capacitors are needed to complete the application circuit. An adjustable-output version is also available, which allows designers to set an output voltage down to 2.5V minimum using an external resistor divider.

All versions are housed in a 3.0 x 3.0mm DFN6 package with wettable flanks, which is smaller than the DPAK outline of typical competing devices yet maintains high thermal performance and excellent reliability in relation to heatsink size.

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RS485-networking transceiver simplifies design to save space

Providing an external pin to select 20Mb its per second or 250kbits per second communication, the STR485LV is a 3.3V transceiver for RS485[1] applications that interfaces directly with low-voltage logic down to 1.8V.

The user-selectable data rate allows designers to specify the same device, simplifying inventory management for RS485-networking applications, ranging from high-speed/short-range up to the maximum communication distance (4,000 feet) depending on cable performance. The transceiver is suitable for telecomms infrastructure, high-speed data links, or low-voltage microcontroller communications.

Low voltage logic devices from 1.8V to 3.3V can be connected directly, without needing level-shifting components, advises ST Microelectronics, leveraging the 1.65 to 3.6V supply voltage range for data and enable signals. By maintaining internal driver-output resistance above 96Ohms up to 105 degrees C, the STR485 allows up to 256 transceivers on the same bus in accordance with the RS485 specification.

Features include thermal shutdown to prevent bus contention or faults causing excessive power consumption, and a receiver failsafe mode that prevents errors if inputs are idle, shorted, or unconnected. The bus pins withstand over ±8kV contact discharge and ±16kV air discharge without latch-up, exceeding IEC 61000-4-2 specifications, and are resistant to IEC61000-4-4 fast transient burst class-B.

Packaged as a 3.0 x 3m.0m DFN10, the STR485 has flow-through logic-to-bus pinning that simplifies board design, adds ST Microelectronics.

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Omnipolar Hall-effect sensors are stable over a wide operating range

Digital Hall-effect sensors from Diodes combine what the company describes as maket-leading stable operating and release points (Bop and Brp) with low power operation. The AH1911 and AH1912 sensors are both available in the industry standard SC59 package.

The AH1911 sensors will respond to either polarity of magnetic field, explains the company, and have a ‘hibernating clock’ system to reduce average current consumption to 1.6 microA at 3V supply.

The wide operating voltage range of 1.6 to 5.5V enables the parts to be used with a variety of system voltages. Operating and release points for the magnetic switch are tightly controlled over temperature and supply voltage due to a stabilising technique, delivering accurate and repeatable performance. Flux density switching points are typically ±60 Gauss (6mT) to operate and ±45 Gauss (4.5mT) to release.

Both the AH1911 and AH1921 are suitable for battery-powered devices where its low power consumption and wider operating voltage range promote extended battery life. Typical applications include medical and consumer products, tamper detection for e-meters, smoke detectors, IoT devices and general level/proximity detection.

The AH1911 and AH1921 feature push-pull and open-drain outputs, respectively. Both are specified to operate over the -40 to +85 degrees C temperature range and have a high ESD rating of 6kV (human body model).

This news story is brought to you by softei.com, the specialist site dedicated to delivering information about what’s new in the electronics industry, with daily news updates, new products and industry news.

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Asset management pinpoints vehicles for inventory tracking

Enhancing productivity in the automotive industry, Silicon Labs and Cognosos have collaborated to develop a wireless networking device to improve managing inventories.

Built on the Silicon Labs Flex Gecko system-on-a-chip (SoC), the Cognosos RadioTrax) tag enables employees to perform quick online searches or use their smartphones to pinpoint the location and movement history of cars stored in distributed car parks, increasing productivity and saving time.

Organisations with large inventories are frequently required to locate cars at a moment’s notice for maintenance, test drives or auctions. Large operations manage thousands of cars and often have multiple parking locations, creating a tracking challenge that can slow down business operations.

“Cognosos identified a time-intensive problem within the automotive industry and applied new IoT technology to create a superior experience for business operators,” said Ross Sabolcik, vice president and general manager of IoT products at Silicon Labs. “The Flex Gecko wireless SoC helped reduce the size, cost and complexity of the RadioTrax tag,” he added.

The end user uses a smartphone application to scan the RadioTrax tag and associates it by scanning the car’s VIN or stock number. The vehicle quickly shows up on a digital map, along with instructions on how to reach it. The Cognosos RadioTrax tag is secured to the visor or rear-view mirror of every car and transmits a sub-GHz radio message using patented wireless technology. The RF device includes an accelerometer to detect motion whenever the car is moved. Unlike previous RFID alternatives requiring extensive infrastructure and only showing the last known location of a car, RadioTrax displays the car’s real-time location.

Jim Stratigos, co-founder and CTO of Geo IoT platform provider, Cognosos, said: “The Flex Gecko SoC enabled us to pack more wireless and processing functionality into our device while using less power.”

Cognosos’ RadioCloud platform enables enterprises to deploy value-creating services with greater reliability and at a fraction of the cost of competing approaches.

Silicon Labs provides silicon and software for a smarter, more connected world, serving the IoT, internet infrastructure, industrial automation, consumer and automotive markets.

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