Archive : 29 February 2008 год

Chomerics Europe has been able to provide a solution to a thermal management application encountered on an automotive ECU using its silicone-based Therm-A-GAP T630G dispensable form-in-place gap filling material. Previous approaches considered included thermal interface pads, which can be expensive both in terms of component and assembly cost, and thermal greases that have limited thermal performance, are messy to apply, and have performance that may degrade over time. Being fully cured means that Therm-A-GAP T630G does not require a post application curing cycle. Usefully, the material is also re-workable, allowing the ECU to be taken apart and re-assembled without jeopardising thermal performance. The thixotropic nature T630G ensures that it remains at the interface over the life of the product, helping to maintain thermal performance. A further benefit is the low (less than 1 PSI/6.9 kPa) force required to deflect the material and create an effective thermal path between the device and chassis or housing.

Linear Technology introduces the LTC2919, a versatile triple supervisor that monitors its own supply voltage and two adjustable inputs. Polarity selection and a buffered reference output allow the LTC2919 to monitor a combination of two positive or negative supplies for undervoltage (UV) and overvoltage (OV) conditions. The two inputs have a nominal 0.5V threshold and tight ±1.5% accuracy over the full temperature range. In addition to monitoring the two adjustable inputs for UV or OV, the LTC2919 monitors the supply voltage at 2.5V, 3.3V or 5V at a fixed -10% UV. The adjustable trip thresholds are set with an external resistive divider network, giving users complete control over the trip point. Offered in the tiny MSOP-10 and 3mm x 2mm DFN-10 packages, this supervisor draws only 50uA.

With guaranteed specifications across the -40°C to +125°C temperature range, the LTC2919 can be used in a wide variety of designs, including network servers and multirail systems. The LTC2919 includes a common open-drain reset output and two open-drain comparator outputs that indicate the status of the adjustable inputs. The individual comparator outputs simplify sequencing positive and negative supplies. The reset timeout period can be set to a fixed 400us, fixed 200ms, an adjustable period, or disabled for fast response. Glitch filtering ensures reliable reset operation without false triggering and the LTC2919 guarantees the reset output once VCC rises above 0.5V. In addition to monitoring low voltages, the LTC2919’s VCC supply includes a 6.5V shunt regulator, which when connected to an external current limiting resistor, allows a high voltage supply to power the device. This makes the LTC2919 a good fit for multichannel low voltage designs and high voltage positive or negative monitoring.

The LTC2919 is available today in commercial, industrial, and automotive temperature grades, with pricing beginning at $1.75 each, in 1,000-piece quantities.