A3230 ALLEGRO | Alldatasheet
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A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com Allegro MicroSystems, Inc. AB SO LUTE MAX I MUM RAT INGS Operating Temperature Ambient, T Chopper-Stabilized Hall-Effect Bipolar Switch Package LH, 3-pin Surface Mount Features and Benefi ts Package UA, 3-pin SIP Chopper stabilization y Superior temperature stability y Extremely low switchpoint drift y Insensitive to physical stress Reverse battery protection Output short circuit protection Solid state reliability Small size Robust EMC capability High ESD ratings (HBM) The A3230 Hall-effect sensor is a temperature stable, stress-resistant bipolar switch. This sensor is the most sensitive Hall-effect device in the Allegro® bipolar switch family and is intended for ring-magnet sensing. Superior high-temperature performance is made possible through an Allegro patented dynamic offset cancel- lation that utilizes chopper-stabilization. This method reduces the offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. The A3230 includes the following on a single silicon chip: a voltage regulator, Hall-voltage generator, small-signal amplifi er, chopper stabilization, Schmitt trigger, and a short circuit protected open-drain output. Advanced BiCMOS wafer fabrication processing takes advantage of low-voltage requirements, component matching, very low input-offset errors, and small component geometries. The A3230 Hall-effect bipolar switch turns on in a south polarity magnetic fi eld of suffi cient strength and switches off in a north polarity magnetic fi eld of suffi cient strength. Because the output state is not defi ned if the magnetic fi eld is diminished or removed, to ensure that the device switches, Allegro recommends using mag- nets of both polarities and of suffi cient strength in the application. The A3230 is rated for operation between the ambient temperatures –40°C and 85°C for the E temperature range, and –40°C to 150°C for the L temperature range. Two A3230 package styles provide magnetically optimized solutions for most applications. Package LH is a SOT23W, a miniature low-profi le surface-mount package, while package UA is a three-lead ultramini SIP for through-hole mounting. Each package is available in a lead (Pb) free version, with 100% matte tin plated leadframes. 1 32 VCC GND VOUT 1 2 VCC VOUT GND 1 2 3
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 Product Selection Guide Functional Block Diagram Regulator GND VCC VOUT Control Current Limit <1Ω Dynamic Offset Cancellation Sample and Hold To All Subcircuits Amp Low-Pass Filter Terminal List Name Description Number Package LH Package UA VCC Connects power supply to chip 1 1 VOUT Output from circuit 2 3 GND Ground 3 2 Part Number Pb- free Packing* Mounting Ambient, TA (°C) BRP(MIN) (G) BOP(MAX) (G) A3230ELHLT – 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40 to 85 –25 25 A3230ELHLT-T Yes A3230EUA – Bulk, 500 pieces/bag 3-pin SIP through holeA3230EUA-T Yes A3230LLHLT – 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount –40 to 150A3230LLHLT-T Yes A3230LUA – Bulk, 500 pieces/bag 3-pin SIP through holeA3230LUA-T Yes *Contact Allegro for additional packing options.
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 OPERATING CHARACTERISTICS valid over full operating voltage and ambient temperature ranges, unless otherwise noted Characteristic Symbol Test Conditions Min. Typ. Max. Units
Electrical Characteristics
1 VCC Operating, TJ < 165°C 3.6 – 24 V Output Leakage Current I OUTOFF VOUT = 24 V, B < BRP – – 10 µA Output On Voltage V OUT(SAT) IOUT = 20 mA, B > BOP – 250 500 mV Output Current Limit I OM B > BOP 30 – 60 mA Power-On Time t PO VCC > 3.6 V – 8 50 µs Chopping Frequency f c – 200 – kHz Output Rise Time2 tr RLOAD = 820 Ω, CS = 20 pF – 0.2 1 µs Output Fall Time2 tf RLOAD = 820 Ω, CS = 20 pF – 0.2 1 µs Supply Current ICCON B > BOP – 1.6 5 mA ICCOFF B < BRP – 1.6 5 mA Reverse Battery Current I RCC VRCC = –18 V – – –2 mA Supply Zener Clamp Voltage V Z ICC = 8 mA; TA = 25°C 28 – – V Supply Zener Current3 IZ VS = 28 V – – 8 mA Magnetic Characteristics4 Operate Point B OP South pole adjacent to branded face of device –10 7.5 25 G Release Point B RP North pole adjacent to branded face of device –25 –7.5 10 G Hysteresis B HYS BOP – BRP 51 5 2 5 G 1 Maximum voltage must be adjusted for power dissipation and junction temperature, see Power Derating section. 2 CS = oscilloscope probe capacitance. 3 Maximum current limit is equal to the maximum ICC(MAX) + 3 mA. 4 Magnetic fl ux density, B, is indicated as a negative value for north-polarity magnetic fi elds, and as a positive value for south-polarity magnetic fi elds. This so-called algebraic convention supports arithmetic comparison of north and south polarity values, where the relative strength of the fi eld is indicated by the absolute value of B, and the sign indicates the polarity of the fi eld (for example, a –100 G fi eld and a 100 G fi eld have equivalent strength, but opposite polarity). DEVICE QUALIFICATION PROGRAM Contact Allegro for information. EMC (Electromagnetic Compatibility) REQUIREMENTS Contact Allegro for information.
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 Electrical Characteristic Data TA (°C) Supply Current (On) versus Ambient Temperature VCC (V) ICCON (mA) 24 3.6 TA (°C) Supply Current (Off) versus Ambient Temperature VCC (V) ICCOFF (mA) 24 3.6 TA (°C) Output Voltage (On) versus Ambient Temperature VCC (V) VOUT(SAT) (mV) 3.6 Supply Current (On) versus Supply Voltage TA (°C) ICCON (mA) VCC (V) –40 150 Supply Current (Off) versus Supply Voltage TA (°C) ICCOFF (mA) VCC (V) –40 150 Output Voltage (On) versus Supply Voltage TA (°C) VOUT(SAT) (mV) VCC (V) –40 150 1.0 2.0 3.0 4.0 5.0 1.0 2.0 3.0 4.0 5.0 1.0 2.0 3.0 4.0 5.0 1.0 2.0 3.0 4.0 5.0 –50 0 50 100 150 0 5 10 15 20 25 –50 0 50 100 150 0 5 10 15 20 25 –50 0 50 100 150 0 5 10 15 20 25 200 250 100 150 300 350 400 450 500 200 250 100 150 300 350 400 450 500
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 VCC (V) 3.8 TA (°C) VCC (V) 3.8 VCC (V) 3.8 TA (°C) –40 150 TA (°C) –40 150 TA (°C) –40 150 Operate Point versus Ambient Temperature BOP (G) TA (°C) Release Point versus Ambient Temperature BRP (G) TA (°C) Hysteresis versus Ambient Temperature BHYS (G) BOP (G)BRP (G)BHYS (G) Operate Point versus Supply Voltage Release Point versus Supply Voltage VCC (V) VCC (V) TA (°C) VCC (V) Hysteresis versus Supply Voltage –50 0 50 100 150 0 5 10 15 20 25 –50 0 50 100 150 0 5 10 15 20 25 –50 0 50 100 150 0 5 10 15 20 25 -10 -10 -25 -20 -15 -10 -25 -20 -15 -10 Magnetic Characteristic Data
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions Value Units Package Thermal Resistance RθJA Package LH, minimum-K PCB (single-sided with copper limited to solder pads) 110 ºC/W Package LH, low-K PCB (double-sided with 0.926 in2 copper area) 228 ºC/W Package UA, minimum-K PCB (single-sided with copper limited to solder pads) 165 ºC/W Power Derating Curve TJ(max) = 165°C; ICC = ICC(max) 20 40 60 80 100 120 140 160 180 Temperature (°C) Maximum Allowable V CC (V) Low-K PCB, Package LH (R θJA = 110 °C/W) Minimum-K PCB, Package UA (R θJA = 165 °C/W) Minimum-K PCB, Package LH VCC(max) VCC(min) (R θJA = 228 °C/W) Power Dissipation versus Ambient Temperature 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 20 40 60 80 100 120 140 160 180 Temperature (°C) Power Dissipation, P D (mW) Low-K PCB, Package LH (R JA = 110 °C/W) Min-K PCB, Package LH (R JA = 228 °C/W) Min-K PCB, Package UA (R JA = 165 °C/W)
vibration and electrical noise. mined by the switchpoint characteristics of the individual device. Figure 1. Bipolar Device Output Switching Modes. These behaviors can be exhibited when using a circuit such as that shown in panel D. Panel A such as the A3230, can operate in any of the three modes.
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 exhibiting negative switch behavior operate in a similar but opposite manner. A north polarity fi eld of suffi cient strength, > BRP , (more north than BRP) is required for operation, although the result is that VOUT switches high, as shown in panel C. When the fi eld is reduced beyond the BOP level, the device switches back to the low state. The A3230 is designed to attain a small hysteresis, and thereby provide more sensitive switching. Although this means that true latching behavior cannot be guaranteed in all cases, proper switching can be ensured by use of both south and north mag- netic fi elds, as in a ring magnet. Bipolar devices adopt an indeterminate output state when powered-on in the absence of a magnetic fi eld or in a fi eld that lies within the hysteresis band of the device. The correct state is attained after the fi rst excursion beyond B OP or BRP. For more information on Bipolar switches, refer to Application Note 27705, Understanding Bipolar Hall Effect Sensors.
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 Panel B of fi gure 1, a 0.1µF capacitor is typical. Extensive applications information on magnets and Hall-effect sensors is available in:
- Hall-Effect IC Applications Guide, AN27701,
- Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead Welding and Lead Forming, AN27703.1
- Soldering Methods for Allegro’ s Products – SMT and Through- Hole, AN26009 All are provided in Allegro Electronic Data Book, AMS-702 and the Allegro Web site: www.allegromicro.com
Figure 2. Chopper Stabilization Circuit (Dynamic Quadrature Offset Cancellation) ating temperature and voltage ranges. of the output drift induced by thermal and mechanical stresses. contact your Allegro sales representative.
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 The device must be operated below the maximum junction temperature of the device, TJ(max). Under certain combinations of peak conditions, reliable operation may require derating sup- plied power or improving the heat dissipation properties of the application. This section presents a procedure for correlating factors affecting operating T J. (Thermal data is also available on the Allegro MicroSystems Web site.) The Package Thermal Resistance, RθJA, is a fi gure of merit sum- marizing the ability of the application and the device to dissipate heat from the junction (die), through all paths to the ambient air. Its primary component is the Effective Thermal Conductivity, K, of the printed circuit board, including adjacent devices and traces. Radiation from the die through the device case, R θJC, is relatively small component of RθJA. Ambient air temperature, TA, and air motion are signifi cant external factors, damped by overmolding. The effect of varying power levels (Power Dissipation, PD), can be estimated. The following formulas represent the fundamental relationships used to estimate T J, at PD. PD = VIN × IIN (1) ∆ T = PD × RθJA (2) T J = TA + ∆T (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 1.5 mA, and RθJA = 165 °C/W, then: P D = VCC × ICC = 12 V × 1.5 mA = 18 mW ∆ T = PD × RθJA = 18 mW × 165 °C/W = 3°C A worst-case estimate, PD(max), represents the maximum allow- able power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RθJA and TA. Example: Reliability for VCC at TA = 150°C, package LH, using a low-K PCB. Observe the worst-case ratings for the device, specifi cally: RθJA = 228 °C/W, TJ(max) = 165°C, VCC(max) = 24 V , and ICC(max) = 5 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: ∆Tmax = TJ(max) – TA = 165 °C – 150 °C = 15 °C This provides the allowable increase to TJ resulting from internal power dissipation. Then, invert equation 2: PD(max) = ∆Tmax ÷ RθJA = 15°C ÷ 228 °C/W = 66 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC(max) = 66 mW ÷ 5 mA = 13 V The result indicates that, at TA, the application and device can dissipate adequate amounts of heat at voltages ≤VCC(est). Compare VCC(est) to VCC(max). If VCC(est) ≤ VCC(max), then reli- able operation between VCC(est) and VCC(max) requires enhanced RθJA. If VCC(est) ≥ VCC(max), then operation between VCC(est) and VCC(max) is reliable under these conditions. Power Derating
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 Package LH, 3-Pin (SOT-23W) Package UA, 3-Pin
A3230-DS Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com Allegro MicroSystems, Inc. Chopper-Stabilized Hall Effect Bipolar Switch A3230 The products described herein are manufactured under one or more of the following U.S. patents: 5,045,920; 5,264,783; 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 permit 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 products are not authorized for use as critical compo- nents in life-support devices or sys tems without express written approval. 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 i ty for its use; nor for any in fringe ment of patents or other rights of third parties which may result from its use. Copyright © 2005 Allegro MicroSystems, Inc.