A1172资料

A1172

Micropower Ultra-Sensitive Hall-Ef fect SwitchFeatures and Benefits▪ Micropower operation▪ Operation with either north or south pole—no magnetic orientation required during assembly▪ 1.65 to 3.5 V battery operation▪ Chopper stabilization▫ Superior temperature stability▫ Extremely low switchpoint drift▫ Insensitive to physical stress▪ Sol id state reliability▪ Small size: WLCSP (≈ 1 mm × 1 mm × 0.5 mm)▪ Complementary, push-pull outputs eliminate need for pull-up resistorDescriptionThe A1172 is an ultra-sensitive, pole-independent Hall-effect switch with a latched digital output. It features operation at low supply currents and voltages, making it ideal for battery-operated electronics. The 1.65 to 3.5 V operating supply voltage and unique clocking algorithm reduce the average operating power requirements to less than 15 μW with a 2.75 V supply.The A1172 has two push-pull output structures. Omnipolar activation for the output function is available on each output structure. As such, either a north or south pole of sufficient strength turns the available outputs off or on. The A1172 contains two complementary outputs. Therefore, for a fixed magnetic field, one output will be in a high voltage state and one output will be in a low voltage state.Improved stability is made possible through dynamic offset cancellation using chopper stabilization, which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. This device Package: 4 pin WLCSP (suffix CG)Not to scaleContinued on the next page…Engineering samples available on a limited basis. Contact your local sales or applications support office for additional information.Functional Block DiagramVDDClock/LogicSample and HoldDynamic OffsetCancellationLatchLow-PassFilterVOUTPSAmpLatchVOUTPNGND1172-DS

元器件交易网www.cecb2b.com

A1172

Description (continued)

Micropower Ultra-Sensitive Hall-Effect Switch

includes, on a single silicon chip, a Hall-voltage generator, a small-signal amplifier, chopper stabilization, a latch, and a MOSFET output.

The A1172 device offers magnetically optimized solutions, suitable for most applications. The wafer level chip scale package (WLCSP) is approximately only 1 mm by 1 mm by 0.5 mm. This package is smaller than most plastic packages and reduces the printed circuit board area consumed by micropower Hall-effect switches.Selection Guide

Part Number

A1172ECGLT

PackagePb-free

Pb-free chip with high-temperature solder balls (RoHS compliant)

Packing*

4000 pieces per reel

4 bumped wafer-level chip-scale package (WLCSP)

*Contact Allegro for additional packing options.

Absolute Maximum Ratings

Characteristic

Supply Voltage Reverse Supply VoltageOutput Off VoltageReverse Output VoltageOutput CurrentMagnetic Flux Density

Operating Ambient TemperatureMaximum Junction TemperatureStorage Temperature

SymbolVDDVRDDVOUTxVROUTxIOUTx(Sink)IOUTx(Source)

BTATJ(max)Tstg

Range E

Notes

Rating5–0.35 –0.3–11Unlimited–40 to 85165–65 to 170

UnitsVVVVmAmAGºCºCºC

Pin-out Diagram

A1B1A2B2Terminal List Table

NameVOUTPSVOUTPNGNDVDD

NumberA1A2B1B2

Push-pull outputInverted push-pull outputGround

Connects power supply to chip

Function

(Bump-down view)

Allegro MicroSystems, Inc.115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

2

元器件交易网www.cecb2b.com

A1172

OPERATING CHARACTERISTICS

Characteristic

Supply Voltage Range2Output On VoltageMode Cycle PeriodChopping Frequency

Micropower Ultra-Sensitive Hall-Effect Switch

Symbol

VDDVOUT(SAT)VOUT(HIGH)tPeriodfCIDD(EN)

Test Conditions

Operating, TA= 25°C

NMOS on, IOUT = 1 mA, VDD = 2.75 VPMOS on, IOUT = 1 mA, VDD = 2.75 V

Min.

1.65–––

Typ.1

–10050200––4632–3226–266

Max.

3.5300–100–2.08.081255–––6–

Units

VmVmVmskHzmAμAμAμAGGGGG

Electrical Characteristics valid over full operating voltage range and TA = 25°C

VDD–300VDD–100

Chip awake (enabled)Chip asleep (disabled)VDD = 1.80 VVDD = 3.5 V

––––––556–

Supply Current

IDD(DIS)IDD(AV)

Magnetic Characteristics3 at TA = 25°C and 1.8 V ≤ VDD ≤ 3.5 V

Operate PointRelease PointHysteresis

1Typical values at V

BOPSBOPNBRPSBRPNBHYS

BHYS = BOPX – BRPX

–

DD = 2.75 V. Performance may vary for individual units, within the specified maximum and minimum limits.

2Magnetic operate and release points vary with supply voltage.31 gauss (G) is exactly equal to 0.1 millitesla (mT).

Allegro MicroSystems, Inc.115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

3

元器件交易网www.cecb2b.com

A1172Micropower Ultra-Sensitive Hall-Effect Switch

Operating Characteristics

SaturationVoltageversusTemperature300250VOUT(SAT)(mV)VDD=1.65VVDD=2.75VVDD=3.5V200150100500-60-40-20020TA(°C)406080100SaturationVoltageversusSupplyVoltage300250VOUT(SAT)(mV)85°C-40°C25°C20015010050011.522.5VCC(V)33.54Allegro MicroSystems, Inc.115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

4

元器件交易网www.cecb2b.com

A1172Micropower Ultra-Sensitive Hall-Effect Switch

AverageSupplyCurrentversusTemperature121086420-60-40-20020TA(°C)406080100VDD=1.65VVDD=2.75VVDD=3.5VIDD(AV)(uA)AverageSupplyCurrentversusSupplyVoltage12108IDD(AV)(μA)85°C-40°C25°C642011.522.5VCC(V)33.54Allegro MicroSystems, Inc.115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

5

元器件交易网www.cecb2b.com

A1172Micropower Ultra-Sensitive Hall-Effect Switch

PeriodversusTemperature100908070tperiod(ms)VDD=1.65VVDD=2.75VVDD=3.5V6050403020100-60-40-20020TA(°C)406080100PeriodversusSupplyVoltage100908070tperiod(ms)85°C-40°C25°C605040302010011.522.5VCC(V)33.54Allegro MicroSystems, Inc.115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

6

元器件交易网www.cecb2b.com

A1172Micropower Ultra-Sensitive Hall-Effect Switch

Functional Description

Low Average Power

Internal timing circuitry activates the sensor for 50 μs and deactivates it for the remainder of the period (50 ms). A short awake time allows stabilization prior to the sensor sampling and data-latching on the falling edge of the timing pulse. The output during the sleep state is latched in the last sampled state. The supply current is not affected by the output state.

tPeriodAwakeIDD(EN)SleepBOPS (or is less than BOPN). After turn-on, the output voltage is VOUT(SAT). The output transistor is capable of sinking cur-rent up to the short circuit current limit, IOM, which is a mini-mum of 1 mA. When the magnetic field is reduced below the release point, BRPS (or increased above BRPN), the device output switches high (turns off). The pull-up transistor brings the output voltage to VOUT(HIGH).

VOUTPN operates with the opposite output polarity. That is, the output is low (on) in the absence of a magnetic field. The output goes high (turns off) when sufficient field, of either north or south polarity, is presented to the device.

The difference in the magnetic operate and release points is the hysteresis, BHYS , of the device. This built-in hysteresis allows clean switching of the output even in the presence of external mechanical vibration and electrical noise.

IDD(DIS)0Sample and Output LatchedOperation

The VOUTPS output switches low (turns on) when a magnetic field perpendicular to the Hall sensor exceeds the operate point,

The push-pull outputs are capable of sourcing or sinking a maxi-mum of 1 mA.

Powering-on the device in a hysteresis region, between BOPX and BRPX, allows an indeterminate output state. The correct state is attained after the first excursion beyond BOPX or BRPX.

(A) VOUTPS

V+Switch to HighSwitch to HighSwitch to LowSwitch to LowVOUT(HIGH)

V+Switch to High(B) VOUTPN

VOUT(HIGH)

Switch to HighSwitch to LowSwitch to LowVOUTVOUT(SAT)

0BRPNBRPSB–0B+0B–BHYS

0B+BHYS

VOUTVOUT(SAT)

Figure 1. Switching Behavior of Omnipolar Switches. On the horizontal axis, the B+ direction indicates increasing south polarity magnetic field strength, and the B– direction indicates decreasing south polarity field strength (including the case of increasing north polarity).

BOPNBHYS

BOPSBHYS

Allegro MicroSystems, Inc.115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

7

元器件交易网www.cecb2b.com

A1172Micropower Ultra-Sensitive Hall-Effect Switch

Applications

It is strongly recommended that an external bypass capacitor be connected (in close proximity to the Hall sensor) between the supply and ground of the device to reduce both external noise and noise generated by the chopper stabilization technique. As is shown in figure 2, a 0.1 μF capacitor is typical.

Extensive applications information on magnets and Hall-effect sensors is available in the following notes:

• Hall-Effect IC Applications Guide, AN27701

• Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead Welding and Lead Forming AN27703.1• Soldering Methods for Allegro Products (SMD and Through-Hole), AN26009All are provided in Allegro Electronic Data Book, AMS-702, and on the Allegro Web site, www.allegromicro.com.

VSCBYP0.1 μFSensor OutputsVOUTPSVOUTPNA1172GNDVDDFigure 2. Typical Application Circuit

Allegro MicroSystems, Inc.115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

8

元器件交易网www.cecb2b.comA1172Micropower Ultra-Sensitive Hall-Effect SwitchPackage CG, 4-Bump WLCSP

0.95512󰀔X󰂅󰀐.160AA0.955BBA0.500120.500CSEATINGPLANE4X0.05C󰂅0.200PCB Layout Reference View0.555 MAXC0.227All dimensions nominal, not for tooling useDimensions in millimetersExact configuration at supplier discretion within limits shown0.228B0.500ABATerminal #A1 mark area (substrate side)BHall element (not to scale)CReference view of typical layout for solder padsAll pads a minimum of 0.20 mm from all adjacent pads;adjust as necessary to meet application process requirements and PCB layout tolerances10.5002Copyright ©2008, Allegro MicroSystems, Inc.

The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 5,442,283; 5,389,889; 5,581,179; 5,517,112; 5,619,137; 5,621,319; 5,650,719; 5,686,894; 5,694,038; 5,729,130; 5,917,320; and other patents pending.Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec i fi ca tions as may be required to per-mit improvements in the per for mance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current.

Allegro’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system.The in for ma tion in clud ed herein is believed to be ac cu rate and reliable. How ev er, Allegro MicroSystems, Inc. assumes no re spon si bil ity for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use.

For the latest version of this document, visit our website:

www.allegromicro.com

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.com

9