A1205LUA-T

A1205 Continuous-Time Bipolar Switch Features and Benefits ▪ Ideal for applications that require pulsing VCC to conserve power ▪ Continuous-time operation ▫ Fast power-on time ▫ Low noise ▪ Stable operation over full operating temperature range ▪ Reverse battery protection ▪ Solid-state reliability ▪ Factory-programmed at end-of-line for optimum performance ▪ Robust EMC performance ▪ High ESD rating ▪ Regulator stability without a bypass capacitor Description The Allegro® A1205 Hall-effect bipolar switch is a nextgeneration replacement and extension of the popular Allegro A3134 bipolar switch. The A1205 has identical specifications as the A1201 but is recommended for applications that require pulsing VCC to conserve power. For standard applications, where VCC is constant, please refer to the A1201 through A1204 devices. Overall, the A120x family, produced with BiCMOS technology, consists of continuous-time devices that feature fast poweron time and low-noise operation. Device programming is performed after packaging to ensure increased switchpoint accuracy by eliminating offsets that can be induced by package stress. Unique Hall element geometries and lowoffset amplifiers help to minimize noise and to reduce the residual offset voltage normally caused by device overmolding, temperature excursions, and thermal stress. The A120x Hall-effect bipolar switches include the following on a single silicon chip: voltage regulator, Hall-voltage generator, Packages: 3 pin SOT23W (LH) 3 pin SIP (UA) Continued on the next page… Not to scale Functional Block Diagram VCC Regulator To all subcircuits VOUT Amp Gain Offset Tri m Control GND A1205-DS, Rev. 1 A1205 Description (continued) small-signal amplifier, Schmitt trigger, and NMOS output transistor. The integrated voltage regulator permits operation from 3.8 to 24 V. The extensive on-board protection circuitry makes possible a ±30 V absolute maximum voltage rating for superior protection in automotive and motor commutation applications, without adding external components. Continuous-Time Bipolar Switch The small geometries of the BiCMOS process allow these devices to be provided in ultrasmall packages. The package styles available provide magnetically optimized solutions for most applications. Package LH is a SOT23W miniature thin-profile surface-mount package, while package UA is a three-lead ultramini SIP for throughhole mounting. Each package is lead (Pb) free, with 100% matte tin plated leadframes. Selection Guide Part Number A1205ELHLT-T A1205EUA-T A1205LLHLT-T A1205LUA-T Packing* 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag 7-in. reel, 3000 pieces/reel Bulk, 500 pieces/bag Mounting 3-pin SOT23W surface mount 3-pin SIP through hole 3-pin SOT23W surface mount 3-pin SIP through hole Ambient, TA –40ºC to 85ºC –50 –40ºC to 150ºC 50 BRP (Min) BOP (Max) *Contact Allegro for additional packing options. Absolute Maximum Ratings Characteristic Supply Voltage Reverse Supply Voltage Output Off Voltage Reverse Output Voltage Output Current Sink Magnetic Flux Density Operating Ambient Temperature Maximum Junction Temperature Storage Temperature Symbol VCC VRCC VOUT VROUT IOUTSINK B Notes Rating 30 –30 30 –0.5 25 Unlimited Units V V V V mA G ºC ºC ºC ºC TA TJ(max) Tstg Range E Range L –40 to 85 –40 to 150 165 –65 to 170 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 2 A1205 Characteristic Electrical Characteristics Supply Voltage1 Output Leakage Current Output On Voltage Power-On Time2 Output Rise Time3 Output Fall Time3 VCC IOUTOFF VOUT(SAT) tPO tr tf ICCON ICCOFF IRCC VZ IZ BOP BRP BHYS Symbol Continuous-Time Bipolar Switch Test Conditions Operating, TJ < 165°C VOUT = 24 V, B < BRP IOUT = 20 mA, B > BOP Slew rate (dVCC/dt) < 2.5 V/μs, B > BOP + 5 G or B < BRP – 5 G VCC = 12 V, RLOAD = 820 Ω, CS = 12 pF VCC = 12 V, RLOAD = 820 Ω, CS = 12 pF B > BOP B < BRP VRCC = –30 V ICC = 30 mA; TA = 25°C VZ = 32 V; TA = 25°C South pole adjacent to branded face of device North pole adjacent to branded face of device BOP – BRP Min. 3.8 – – – – – – – – 32 – –40 –50 5 Typ. – – 215 – – – 3.8 3.5 – – – 15 –15 30 Max. 24 10 400 4 2 2 7.5 7.5 –10 40 30 50 40 55 Units V µA mV µs µs µs mA mA mA V mA G G G OPERATING CHARACTERISTICS over full operating voltage and ambient temperature ranges, unless otherwise noted Supply Current Reverse Battery Current Supply Zener Clamp Voltage Supply Zener Current Magnetic Characteristics4 Operate Point Release Point Hysteresis 1 Maximum voltage must be adjusted for power dissipation and junction temperature, see Power Derating section. 2 For V CC slew rates greater than 2.5 V/μs, and TA = 150°C, the Power-On Time can reach its maximum value. 3 C =oscilloscope probe capacitance. S 4 Magnetic flux density, B, is indicated as a negative value for north-polarity magnetic fields, and as a positive value for south-polarity magnetic fields. This so-called algebraic convention supports arithmetic comparison of north and south polarity values, where the relative strength of the field is indicated by the absolute value of B, and the sign indicates the polarity of the field (for example, a –100 G field and a 100 G field have equivalent strength, but opposite polarity). Reference to the magnetic field polarity is with respect to the beveled face of the device. DEVICE QUALIFICATION PROGRAM Contact Allegro for information. EMC (Electromagnetic Compatibility) REQUIREMENTS Contact Allegro for information. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 3 A1205 Continuous-Time Bipolar Switch THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Test Conditions* Package LH, 1-layer PCB with copper limited to solder pads Package Thermal Resistance RθJA Package LH, 2-layer PCB with 0.463 in.2 of copper area each side connected by thermal vias Package UA, 1-layer PCB with copper limited to solder pads *Additional thermal information available on Allegro Web site. Value Units 228 110 165 ºC/W ºC/W ºC/W 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 20 Power Derating Curve TJ(max) = 165ºC; ICC = ICC(max) VCC(max) Package LH, 1-layer PCB (R JA = 228 ºC/W) Maximum Allowable VCC (V) Package UA, 1-layer PCB (R JA = 165 ºC/W) Package LH, 2-layer PCB (R JA = 110 ºC/W) VCC(min) 40 60 80 100 120 140 160 180 Power Dissipation versus Ambient Temperature 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 20 Power Dis s ipat ion, PD (m W) 2l (R aye rP θJ C A= 11 B, P 0 º ac 1-la C/ ka W (R yer PC ) ge L θJA = B H 165 , Pac ºC/ kage W) UA 1-lay er P (R CB, θJA = 228 Packag ºC/W e LH ) 40 60 80 100 120 Temperature (°C) 140 160 180 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 4 A1205 Continuous-Time Bipolar Switch Characteristic Data Supply Current (On) versus Ambient Temperature 8.0 7.0 6.0 8.0 7.0 6.0 Supply Current (On) versus Supply Voltage ICCON (mA) 5.0 4.0 3.0 2.0 1.0 0 –50 0 50 TA (°C) 100 150 ICCON (mA) VCC (V) 24 3.8 5.0 4.0 3.0 2.0 1.0 0 0 5 10 VCC (V) 15 20 25 TA (°C) –40 25 150 Supply Current (Off) versus Ambient Temperature 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 –50 0 50 TA (°C) 100 150 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 0 Supply Current (Off) versus Supply Voltage ICCOFF (mA) ICCOFF (mA) VCC (V) 24 3.8 TA (°C) –40 25 150 5 10 VCC (V) 15 20 25 Output Voltage (On) versus Ambient Temperature 350 300 ILOAD = 20 mA Output Voltage (On) versus Supply Voltage 350 300 VCC (V) 24 3.8 250 TA (°C) –40 25 150 ILOAD = 20 mA VOUT(SAT) (mV) 250 200 150 100 50 0 –50 0 50 TA (°C) 100 150 VOUT(SAT) (mV) 200 150 100 50 0 0 5 10 VCC (V) 15 20 25 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 5 A1205 Continuous-Time Bipolar Switch Operate Point versus Ambient Temperature 50 40 30 20 10 0 -10 -20 -30 -40 -50 0 50 TA (°C) 100 150 VCC (V) 24 3.8 50 40 30 20 10 0 Operate Point versus Supply Voltage TA (°C) –40 25 150 BOP (G) BOP (G) -10 -20 -30 -40 0 5 10 VCC (V) 15 20 25 Release Point versus Ambient Temperature 40 30 20 10 0 -10 -20 -30 -40 -50 -50 0 50 TA (°C) 100 150 VCC (V) 24 3.8 40 30 20 10 0 Release Point versus Supply Voltage TA (°C) –40 25 150 BRP (G) BRP (G) -10 -20 -30 -40 -50 0 5 10 VCC (V) 15 20 25 Hysteresis versus Ambient Temperature 55 50 45 40 35 30 25 20 15 10 5 -50 0 50 TA (°C) 100 150 VCC (V) 24 3.8 55 50 45 40 35 30 25 20 15 10 5 0 Hysteresis versus Supply Voltage BHYS (G) BHYS (G) TA (°C) –40 25 150 5 10 VCC (V) 15 20 25 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 6 A1205 Continuous-Time Bipolar Switch Functional Description Bipolar Device Switching The devices of the A120X family provide highly sensitive switching for applications using magnetic fields of alternating polarities, such as ring magnets. There are three switching modes for bipolar devices, referred to as latch, unipolar switch, and negative switch. Mode is determined by the switchpoint characteristics of the individual device. The characteristic hysteresis, BHYS , of the device, is the difference in the relative magnetic strength and polarity of the switchpoints of the device. (Note that, in the following descriptions, a negative magnetic value indicates a north polarity field, and a positive magnetic value indicates a south polarity field. For a given value of magnetic strength, BX , the values –BX and BX indicate two fields of equal strength, but opposite polarity. B = 0 indicates the absence of a magnetic field.) Bipolar devices typically behave as latches. In this mode, magnetic fields of opposite polarity and equivalent strengths are needed to switch the output. When the magnetic fields are removed (B → 0) the device remains in the same state until a magnetic field of the opposite polarity and of sufficient strength causes it to switch. The hysteresis of latch mode behavior is shown in panel A of figure 1. In contrast to latching, when a device exhibits unipolar switching, it only responds to a south magnetic field. The field must be of sufficient strength, > BOP , for the device to operate. When the field is reduced beyond the BRP level, the device switches back to the high state, as shown in panel B of figure 1. Devices exhibiting negative switch behavior operate in a similar but opposite manner. A north polarity field of sufficient strength, > BRP , (more north than BRP) is required for operation, although the result is that VOUT switches high, as shown in panel C. When VS VCC RL Sensor Output A120x VOUT GND (D) (B) (C) V+ VCC VCC Switch to High Switch to Low (A) V+ VCC Switch to High Switch to High Switch to Low V+ Switch to Low VOUT VOUT VOUT(SAT) 0 BRP BRP B– 0 B+ 0 B– 0 BOP BOP VOUT(SAT) BRP B+ 0 B– 0 BOP VOUT VOUT(SAT) B+ BHYS BHYS BHYS 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 displays the hysteresis when a device exhibits latch mode (note that the BHYS band incorporates B= 0), panel B shows unipolar switch behavior (the BHYS band is more positive than B = 0), and panel C shows negative switch behavior (the BHYS band is more negative than B = 0). Bipolar devices, such as the 120x family, can operate in any of the three modes. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 7 A1205 Continuous-Time Bipolar Switch the field is reduced beyond the BOP level, the device switches back to the low state. The typical output behavior of the A120x devices is latching. However, the A120x family 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 magnetic fields, as in a ring magnet. The hysteresis of the A120x family allows clean switching of the output, even in the presence of external mechanical vibration and electrical noise. Bipolar devices adopt an indeterminate output state when powered-on in the absence of a magnetic field or in a field that lies within the hysteresis band of the device. For more information on Bipolar switches, refer to Application Note 27705, Understanding Bipolar Hall Effect Sensors. CONTINUOUS-TIME BENEFITS Continuous-time devices, such as the A120x family, offer the fastest available power-on settling time and frequency response. Due to offsets generated during the IC packaging process, continuous-time devices typically require programming after packaging to tighten magnetic parameter distributions. In contrast, chopper-stabilized switches employ an offset cancellation technique on the chip that eliminates these offsets without the need for after-packaging programming. The tradeoff is a longer settling time and reduced frequency response as a result of the chopperstabilization offset cancellation algorithm. The choice between continuous-time and chopper-stabilized designs is solely determined by the application. Battery management is an example where continuous-time is often required. In these applications, VCC is chopped with a very small duty cycle in order to conserve power (refer to figure 2). The duty cycle is controlled by the power-on time, tPO, of the device. Because 1 2 3 4 5 VCC t VOUT t Output Sampled tPO(max) Figure 2. Continuous-Time Application, B < BRP.. This figure illustrates the use of a quick cycle for chopping VCC in order to conserve battery power. Position 1, power is applied to the device. Position 2, the output assumes the correct state at a time prior to the maximum Power-On Time, tPO(max). The case shown is where the correct output state is HIGH . Position 3, tPO(max) has elapsed. The device output is valid. Position 4, after the output is valid, a control unit reads the output. Position 5, power is removed from the device. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 8 A1205 Continuous-Time Bipolar Switch continuous-time devices have the shorter power-on time, they are the clear choice for such applications. For more information on the chopper stabilization technique, refer to Technical Paper STP 97-10, Monolithic Magnetic Hall Sensor Using Dynamic Quadrature Offset Cancellation and Technical Paper STP 99-1, Chopper-Stabilized Amplifiers with a Track-and-Hold Signal Demodulator. ADDITIONAL APPLICATIONS INFORMATION Extensive applications information for Hall-effect sensors is available in: • Hall-Effect IC Applications Guide, Application Note 27701 • Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead Welding and Lead Forming, Application Note 27703.1 • Soldering Methods for Allegro’s Products – SMT and ThroughHole, Application Note 26009 All are provided in Allegro Electronic Data Book, AMS-702, and the Allegro Web site, www.allegromicro.com. Pin-out Diagrams Package LH GND Package UA 3 1 VCC 2 VOUT 1 VCC 2 GND 3 VOUT Terminal List Name VCC VOUT GND Description Connects power supply to chip Output from circuit Ground Number Package LH Package UA 1 1 2 3 3 2 Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com  A1205 Continuous-Time Bipolar Switch Power Derating Power Derating 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 supplied power or improving the heat dissipation properties of the application. This section presents a procedure for correlating factors affecting operating TJ. (Thermal data is also available on the Allegro MicroSystems Web site.) The Package Thermal Resistance, RθJA, is a figure of merit summarizing 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, RθJC, is relatively small component of RθJA. Ambient air temperature, TA, and air motion are significant 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 TJ, at PD. PD = VIN × IIN ΔT = PD × RθJA (2) TJ = TA + ΔT (3) (1) Example: Reliability for VCC at TA = 150°C, package UA, using minimum-K PCB. Observe the worst-case ratings for the device, specifically: RθJA = 165°C/W, TJ(max) = 165°C, VCC(max) = 24 V, and ICC(max) = 7.5 mA. Calculate the maximum allowable power level, PD(max). First, invert equation 3: ΔTmax = 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) = ΔTmax ÷ RθJA = 15°C ÷ 165 °C/W = 91 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC(max) = 91 mW ÷ 7.5 mA = 12.1 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 reliable 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. For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 4 mA, and RθJA = 140 °C/W, then: PD = VCC × ICC = 12 V × 4 mA = 48 mW ΔT = PD × RθJA = 48 mW × 140 °C/W = 7°C TJ = TA + ΔT = 25°C + 7°C = 32°C A worst-case estimate, PD(max), represents the maximum allowable power level (VCC(max), ICC(max)), without exceeding TJ(max), at a selected RθJA and TA. Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 10 A1205 Continuous-Time Bipolar Switch Package LH, 3-Pin (SOT-23W) 3.00 .118 2.70 .106 0.15 [.006] M C A B 3.04 .120 2.80 .110 A A 1.49 .059 NOM B 8º 0º 0.20 .008 0.08 .003 3 B 2.10 .083 1.85 .073 Preliminary dimensions, for reference only Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only (reference JEDEC TO-236 AB, except case width and terminal tip-to-tip) Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Hall element (not to scale) B Active Area Depth 0.28 [.011] 3X 0.10 [.004] C 3X 0.50 .020 0.30 .012 0.20 [.008] M C A B 0.95 .037 1.90 .075 A A NOM 0.96 .038 0.60 .024 0.25 .010 1 2 0.25 .010 SEATING PLANE 1.17 .046 0.75 .030 0.15 .006 0.00 .000 C SEATING PLANE GAUGE PLANE Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 11 A1205 Continuous-Time Bipolar Switch Package UA, 3-Pin SIP .164 4.17 .159 4.04 C D .091 2.31 NOM .062 1.57 .058 1.47 D .122 3.10 .117 2.97 .057 1.45 NOM D B .085 2.16 MAX A .031 0.79 REF Dimensions in inches Metric dimensions (mm) in brackets, for reference only A Dambar removal protrusion (6X) B Ejector mark on opposite side C Active Area Depth .0195 [0.50] NOM D Hall element (not to scale) .640 16.26 .600 15.24 .017 0.44 .014 0.35 1 .019 0.48 .014 0.36 2 3 .050 1.27 NOM 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 departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. Copyright ©2006, Allegro MicroSystems, Inc. For the latest version of this document, go to our website at: www.allegromicro.com Allegro MicroSystems, Inc. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 www.allegromicro.com 12