深圳市汇世丰电子有限公司

A3211 and A3212Micropower, Ultrasensitive Hall-Effect Switches Features Micropower operation Operate with north or south pole 2.5 to 3.5 V battery operation Chopper stabilized Superior temperature stability Extremely low switch-point drift Insensitive to physical stress Solid-state reliability Small size Easily manufacturable with magnet pole independence Description The A3211 and A3212 integrated circuits are ultrasensitive, pole independent Hall-effect switches with latched di*al output. These devices are especially suited for operation in battery-operated, hand-held equipment such as cellular and cordless telephones, pagers, and palm* computers. A 2.5 to 3.5 V operation and a unique clocking scheme reduce the average operating power requirements to less than 15 μW with a 2.75 V supply. Unlike other Hall-effect switches, either a north or south pole of sufficient strength will turn the output on in the A3212, and in the absence of a magnetic field, the output is off. The A3211 provides an inverted output. The polarity independence and minimal power requirements allow these devices to easily replace reed switches for *ior reliability and ease of manufacturing, while eliminating the requirement for signal conditioning. Improved stability is made possible through chopper stabilization (dynamic offset cancellation), which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. This device includes on a single silicon chip a Hall-voltage generator, *all-signal amplifier, chopper stabilization, a latch, and a MOSFET output. Advanced CMOS processing is used to take advantage of low-voltage and low-power requirements, component matching, very low input-offset errors, and *all component geometries. Four package styles provide magnetically o