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Rohm launches Hall effect IC switches

Posted: 30 Jun 2008 ?? ?Print Version ?Bookmark and Share

Keywords:Hall effect IC switches? unipolar switches? bipolar switches?

Rohm Hall Effect IC switches

Rohm Electronics formally introduces its complete line of Hall effect ICs for portable electronics applications. An important feature of the product family is its availability in the industry's smallest chip-scale BGA package, measuring just 1.1mm? with a package height of just 0.5mm. A slightly larger surface-mount package, measuring 1.6mm x 1.6mm x 0.6mm, is also available. This mechanical advantage combined with the industry's lowest average current (as low as 3.5?A), fully-integrated compensation and push-pull CMOS logic output circuitry make these devices an attractive alternative to mechanical switches and competitive Hall effect devices.

The integrated dynamic offset cancellation yields high sensitivity to allow for less precise placement of the permanent magnet. The integrated CMOS output eliminates the need for external pull-up resistors. In addition, the devices are rated at 8kV ESD withstand, important for reliable operation in handheld devices. Finally, the Rohm Hall ICs are rated for -40C to 85C operation, which is important for reliable operation in portable consumer electronics.

The Rohm Hall IC switch family includes unipolar switches that can be specified to switch on in the presence of either an S-Pole or N-pole magnetic field of sufficient strength. The output will switch off if the magnetic field is removed. These devices are commonly used in applications like jack-knife or slide-open style cellphones to detect the open state. Power consumption is reduced through the implementation of intermittent sensing with typical response time of 5ms. According to the company, most competitive devices are available in S-Pole-sensing.

Also included in the family are omnipolar switches, which are similar to unipolar types but contains two Hall plates that can be switched on with a either north or south field of sufficient strength. The output will switch off when the field is removed. These devices are used in similar applications as unipolar switches with the added benefit of removing the requirement of placing the magnet polarity.

A third member of the family is polarity discriminating switch, that is similar to omnipolar devices but with separate outputs, that are switched based upon detection of a north or south pole. The output(s) will switch off when the field is removed. These are used in rotating screen devices to detect both open position and orientation.

Finally, the family includes bipolar switches that switch on with a south magnetic field of sufficient strength and switch off with a north magnetic field of sufficient strength. The output will not change if the magnetic field is removed. These devices are used in jog wheel and track ball applications to detect changes in menu selection. They offer extremely fast response time (0.5ms) and high sensitivity (Bop/Brp = 3/-3mT) is required for this application.

Pricing starts at 11 cents for unipolar and 64 cents for bipolar devices, both in OEM quantities. Devices are available now. Delivery is 10-12 weeks ARO.

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