Features: Micropower Operation
Operation with North or South Pole
2.5 V to 3.5 V Battery Operation
Chopper Stabilized
Superior Temperature Stability
Extremely Low Switch-Point Drift
Insensitive to Physical Stress
ESD Protected to 5 kV
Sol id-State Reliability
Small Size
Easily Manufacturable with Magnet Pole IndependenceSpecificationsSupply Voltage, VDD .............................. 5 V
Magnetic Flux Density, B ........................ Unlimited
Output Off Voltage, VOUT ................................ 5 V
Output Current, IOUT .....................................1 mA
Junction Temperature, TJ......................... +170°C
Operating Temperature, TA
Range 'E-' ............................-40°C to +85°C
Range 'L-' ......................... -40°C to +150°C
Storage Temperature Range,
T ....................................... -65°C to +170°CDescriptionThe A3211 and A3212 integrated circuits are ultrasensitive, pole independent Hall-effect switches with latched digital output. These sensors are especially suited for operation in battery-operated, hand-held equipment such as cellular and cordless telephones, pagers, and palmtop computers. A 2.5 to 3.5V operation and a unique clocking scheme reduce the average operating power requirements to less than 15µW with a 2.75V 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 superior 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 A3211 and A3212 includes on a single silicon chip a Hall-voltage generator, small-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 small component geometries.
Four package styles provide magnetically optimized solutions for most applications. Miniature low-profile surface-mount package types EH and EL (0.75 and 0.50mm nominal height) are leadless, LH is a 3-pin low-profile SMD, and UA is a three-pin SIP for through-hole mounting. Packages are lead (Pb) freewith 100% matte tin plated leadframes.
A3212 Data Sheet
