A1205 Continuous-Time Bipolar Switch FEATURES AND BENEFITS DESCRIPTION • 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 Packages: 3 pin SOT23W (LH) 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 power-on 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 low-offset amplifiers help to minimize noise and to reduce the residual offset voltage normally caused by device overmolding, temperature excursions, and thermal stress. 3 pin SIP (UA) The A120x Hall-effect bipolar switches include the following on a single silicon chip: voltage regulator, Hall-voltage generator, 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. Not to scale Continued on the next page… VCC To all subcircuits Regulator VOUT Amp Gain Offset Trim Control GND Functional Block Diagram A12051-DS, Rev. 9 A1205 Continuous-Time Bipolar Switch Description (continued) 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. SPECIFICATIONS Selection Guide Part Number Packing* Mounting A1205LLHLT-T 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1205LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1205LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole Ambient, TA BRP (Min) BOP (Max) –40ºC to 150ºC –50 50 *Contact Allegro for additional packing options. Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage VCC 30 V Reverse Supply Voltage VRCC –30 V Output Off Voltage VOUT 30 V Reverse Output Voltage VROUT –0.5 V IOUTSINK 25 mA Magnetic Flux Density Output Current Sink B Unlimited G Operating Ambient Temperature TA Range E –40 to 85 ºC Range L –40 to 150 ºC Maximum Junction Temperature TJ(max) 165 ºC Tstg –65 to 170 ºC GND Storage Temperature 2 3 VOUT VOUT Package LH Pin-out Diagram 1 GND 2 VCC 1 VCC 3 Package UA Pin-out Diagram Terminal List Number Package LH Package UA 1 1 2 3 3 2 Name VCC VOUT GND Description Connects power supply to chip Output from circuit Ground Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 A1205 Continuous-Time Bipolar Switch OPERATING CHARACTERISTICS over full operating voltage and ambient temperature ranges, unless otherwise noted Characteristic Symbol Test Conditions Min. Typ. Max. Units Electrical Characteristics Supply Voltage1 Output Leakage Current Output On Voltage Power-On Time2 VCC Operating, TJ < 165°C 3.8 – 24 V IOUTOFF VOUT = 24 V, B < BRP – – 10 µA VOUT(SAT) IOUT = 20 mA, B > BOP – 215 400 mV Slew rate (dVCC/dt) < 2.5 V/μs, B > BOP + 5 G or B < BRP –5G – – 4 µs tr VCC = 12 V, RLOAD = 820 Ω, CS = 12 pF – – 2 µs tf VCC = 12 V, RLOAD = 820 Ω, CS = 12 pF – – 2 µs ICCON B > BOP – 3.8 7.5 mA ICCOFF B < BRP – 3.5 7.5 mA VRCC = –30 V – – –10 mA tPO Output Rise Time3 Output Fall Time3 Supply Current Reverse Battery Current IRCC Supply Zener Clamp Voltage VZ ICC = 30 mA; TA = 25°C 32 – 40 V Supply Zener Current IZ VZ = 32 V; TA = 25°C – – 30 mA 50 G Magnetic Characteristics4 Operate Point BOP South pole adjacent to branded face of device –40 15 Release Point BRP North pole adjacent to branded face of device –50 –15 40 G Hysteresis BHYS BOP – BRP 5 30 55 G 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 alge- braic 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 COMPATABILITY) REQUIREMENTS Contact Allegro for information. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A1205 Continuous-Time Bipolar Switch THERMAL CHARACTERISTICS may require derating at maximum conditions, see application information Characteristic Symbol Package Thermal Resistance Test Conditions* RθJA Value Units Package LH, 1-layer PCB with copper limited to solder pads 228 ºC/W Package LH, 2-layer PCB with 0.463 in.2 of copper area each side connected by thermal vias 110 ºC/W Package UA, 1-layer PCB with copper limited to solder pads 165 ºC/W Maximum Allowable VCC (V) *Additional thermal information available on Allegro Web site. Power Derating Curve TJ(max) = 165ºC; ICC = ICC(max) 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 VCC(max) Package LH, 1-layer PCB (R JA = 228 ºC/W) Package UA, 1-layer PCB (R JA = 165 ºC/W) Package LH, 2-layer PCB (R JA = 110 ºC/W) VCC(min) 20 40 60 80 100 120 140 160 180 Power Dissipation, PD (m W) 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 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 ) 20 40 60 80 100 120 Temperature (°C) 140 160 180 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 A1205 Continuous-Time Bipolar Switch CHARACTERISTIC DATA Supply Current (On) versus Ambient Temperature 8.0 8.0 7.0 7.0 VCC (V) 5.0 24 3.8 4.0 3.0 6.0 ICCON (mA) 6.0 ICCON (mA) Supply Current (On) versus Supply Voltage –40 25 150 4.0 3.0 2.0 2.0 1.0 1.0 0 TA (°C) 5.0 0 –50 0 50 TA (°C) 100 150 0 15 20 25 Supply Current (Off) versus Supply Voltage 8.0 8.0 7.0 7.0 6.0 VCC (V) 5.0 24 3.8 4.0 3.0 ICCOFF (mA) ICCOFF (mA) 10 VCC (V) Supply Current (Off) versus Ambient Temperature 6.0 TA (°C) 5.0 –40 25 150 4.0 3.0 2.0 2.0 1.0 1.0 0 0 –50 0 50 TA (°C) 100 0 150 10 15 20 25 Output Voltage (On) versus Supply Voltage ILOAD = 20 mA 350 5 VCC (V) Output Voltage (On) versus Ambient Temperature ILOAD = 20 mA 350 300 300 250 VCC (V) 200 24 3.8 150 100 250 TA (°C) VOUT(SAT) (mV) VOUT(SAT) (mV) 5 200 –40 25 150 150 100 50 50 0 0 –50 0 50 TA (°C) 100 150 0 5 10 15 20 25 VCC (V) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 A1205 Continuous-Time Bipolar Switch Operate Point versus Ambient Temperature 50 40 40 30 30 VCC (V) 10 24 12 3.8 0 –10 –20 TA (°C) 20 BOP (G) 20 BOP (G) Operate Point versus Supply Voltage 50 –40 25 150 10 0 -10 -20 –30 -30 –40 –50 0 50 TA (°C) 100 -40 150 0 15 20 25 25 Release Point versus Supply Voltage 40 40 30 30 20 20 VCC (V) 0 24 12 3.8 –10 –20 –30 TA (°C) 10 BRP (G) 10 BRP (G) 10 Supply Voltage (V) Release Point versus Ambient Temperature –40 25 150 0 -10 -20 -30 –40 -40 –50 –50 0 50 TA (°C) 100 -50 150 0 10 15 20 25 25 Hysteresis versus Supply Voltage 55 55 50 50 45 45 35 VCC (V) 30 24 12 3.8 25 20 15 BHYS (G) 40 40 TA (°C) 35 –40 25 150 30 25 20 15 10 10 5 –50 5 Supply Voltage (V) Hysteresis versus Ambient Temperature BHYS (G) 5 0 50 TA (°C) 100 150 5 0 5 10 15 20 25 25 Supply Voltage (V) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; 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.) ing 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 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 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. VS VCC A120x 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 exhibit(A) GND (D) (C) V+ V+ VOUT B+ B– 0 BRP BHYS B+ BOP BRP B– 0 VOUT(SAT) 0 BOP BOP BHYS VOUT(SAT) 0 BRP B+ 0 Switch to High Switch to High VOUT VOUT(SAT) VCC Switch to Low Switch to Low VOUT VCC Switch to Low Switch to High VCC B– Output VOUT (B) V+ 0 RL 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, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 A1205 Continuous-Time Bipolar Switch 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. in order to conserve power (refer to figure 2). The duty cycle is controlled by the power-on time, tPO, of the device. Because continuous-time devices have the shorter power-on time, they are the clear choice for such applications. For more information on Bipolar switches, refer to Application Note 27705, Understanding Bipolar Hall Effect Sensor ICs. For more information on the chopper stabilization technique, refer to Technical Paper STP 97-10, Monolithic Magnetic Hall Sensing Using Dynamic Quadrature Offset Cancellation and Technical Paper STP 99-1, Chopper-Stabilized Amplifiers with a Track-and-Hold Signal Demodulator. 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 chopper-stabilization offset cancellation algorithm. ADDITIONAL APPLICATIONS INFORMATION Extensive applications information for Hall-effect devices 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 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 1 2 All are provided in Allegro Electronic Data Book, AMS-702, and the Allegro Web site, www.allegromicro.com. 3 4 5 VCC t VOUT t tPO(max) Output Sampled 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, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 A1205 Continuous-Time Bipolar Switch POWER DERATING PD = VCC × ICC = 12 V × 4 mA = 48 mW 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 (1) ΔT = PD × RθJA (2) TJ = TA + ΔT (3) For example, given common conditions such as: TA= 25°C, VCC = 12 V, ICC = 4 mA, and RθJA = 140 °C/W, then: 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. 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. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 A1205 Continuous-Time Bipolar Switch CUSTOMER PACKAGE DRAWINGS For Reference Only – Not for Tooling Use (Reference DWG-2840) Dimensions in millimeters – NOT TO SCALE Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown +0.12 2.98 –0.08 D 1.49 4° ±4° A 3 +0.020 0.180 –0.053 0.96 D +0.19 1.91 –0.06 +0.10 2.90 –0.20 2.40 0.70 D 0.25 MIN 1.00 2 1 0.55 REF 0.25 BSC 0.95 Seating Plane Branded Face Gauge Plane B PCB Layout Reference View 8X 10° REF 1.00 ±0.13 NNT +0.10 0.05 –0.05 0.95 BSC 0.40 ±0.10 A Active Area Depth, 0.28 mm B Reference land pattern layout; all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances N = Last three digits of device part number T = Temperature Code (Letter) C Standard Branding Reference View C Branding scale and appearance at supplier discretion D Hall elements, not to scale Figure 3: Package LH, 3-Pin (SOT-23W) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 A1205 Continuous-Time Bipolar Switch For Reference Only – Not for Tooling Use (Reference DWG-9049) Dimensions in millimeters – NOT TO SCALE Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 45° B 4.09 +0.08 –0.05 1.52 ±0.05 E 2.04 C 2 X 10° 1.44 E 3.02 E Mold Ejector Pin Indent +0.08 –0.05 45° Branded Face 2.16 MAX 0.51 REF A 1 2 0.79 REF 3 0.43 +0.05 –0.07 0.41 +0.03 –0.06 1.27 NOM NNT 15.75 ±0.25 1 D Standard Branding Reference View = Supplier emblem N = Last three digits of device part number T = Temperature code A Dambar removal protrusion (6X) B Gate and tie bar burr area C Active Area Depth, 0.50 mm REF D Branding scale and appearance at supplier discretion E Hall element, not to scale Package UA, 3-Pin SIP Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11 A1205 Continuous-Time Bipolar Switch Revision History Revision Revision Date 8 January 1, 2015 9 July 13, 2015 Description of Revision Added LX option to Selection Guide Corrected LH package Active Area Depth value Copyright ©2006-2015, Allegro MicroSystems, LLC Allegro MicroSystems, LLC 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. Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of Allegro’s product can reasonably be expected to cause bodily harm. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its use; nor for any infringement 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, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12