A3250 Datasheet, PDF (1/15 Pages) Allegro MicroSystems – Field-Programmable, Chopper-Stabilized Unipolar Hall-Effect Switches

A3250 and A3251
Package UA, 3-pin SIP
1
2
3
1. VCC
2. GND
3. VOUT
TL Option
Field-Programmable, Chopper-Stabilized
Unipolar Hall-Effect Switches
The A3250 and A3251 are field-programmable, chopper-stabilized, unipolar Hall-
effect switches designed for use in high-temperature applications. These devices
use a chopper-stabilization technique to eliminate offset inherent in single-element
devices.
The A3250 and A3251 are externally programmable devices. The devices have a
wide range of programmability of the magnetic operate point (B_OP) while the hys-
teresis remains fixed. This advanced feature allows for optimization of the sensor
switchpoint and can drastically reduce the effects of variations found in a produc-
tion environment, such as magnet and device placement tolerances.
These devices provide on-chip transient protection. A Zener clamp on the power
supply protects against overvoltage conditions on the supply line. These devices
also include short-circuit protection on the output.
The output of the A3250 switches LOW when subjected to a south-polarity mag-
netic field with a flux density that exceeds the threshold for B_OP, and switches
HIGH when the field drops below the magnetic release point, B_RP. The output of
the A3251 has the opposite polarity, switching HIGH in a south-polarity magnetic
field that B_OP, and switching LOW when the field drops below B_RP.
The other differences in the devices are the power-on state. The A3250 powers-on
in the HIGH state, while the A3251 powers-on in the LOW state.
These devices are available in a TO-92 three-lead ultra-mini SIP (Single In-line
Package), with either straight or formed and trimmed lead configuration.
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V_CC ...................................... 26.5 V
Reverse-Supply Voltage, V_RCC ........................ –18 V
Zener Overvoltage, V_Z....................................... 30 V
Output Current, I_OUT .........................................20 mA
Magnetic Flux Density, B .........................Unlimited
Operating Temperature
Ambient, T_A, Range J................. –40ºC to 115ºC
Ambient, T_A, Range L................ –40ºC to 150ºC
Maximum Junction, T_J(max)........................165ºC
Storage Temperature, T_S .................. –65ºC to 170ºC
Features and Benefits
Chopper stabilization for stable switchpoints
throughout operating temperature range
Externally programmable operate point
(through VCC pin)
On-board voltage regulator for 4.2 V to 24 V
operation
On-chip protection against:
Supply transients
Output short-circuits
Reverse-battery condition
Use the following complete part numbers when ordering:
Part Number Package
T_A
B_hys(typ)
V_OUT
(ºC)
(G) _{Power-On Running*}
A3250JUA Straight lead
A3250JUATL Formed lead
–40 to 115
18
High
Low
A3250LUA Straight lead
A3250LUATL Formed lead
–40 to 150
13
A3251JUA Straight lead
A3251JUATL Formed lead
–40 to 115
18
Low
High
A3251LUA Straight lead
A3251LUATL Formed lead
–40 to 150
13
*In south polarity magnetic field of sufficient strength.
A3250-DS
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com