A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches FEATURES AND BENEFITS ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ DESCRIPTION AEC-Q100 automotive qualified Unipolar switchpoints Resistant to physical stress Superior temperature stability Output short-circuit protection Operation from unregulated supply Reverse-battery protection Solid-state reliability Small package sizes The A1120, A1121, A1122, A1123, and A1125 Hall-effect unipolar switches are extremely temperature-stable and stress-resistant sensor ICs, especially suited for operation over extended temperature ranges to 150°C. Superior hightemperature performance is made possible through dynamic offset cancellation, which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. Each device includes on a single silicon chip a voltage regulator, Hall-voltage generator, small-signal amplifier, chopper stabilization, Schmitt trigger, and a short-circuit protected open-drain output to sink up to 25 mA. Packages: An on-board regulator permits operation with supply voltages of 3 to 24 V. The advantage of operating down to 3 V is that the device can be used in 3 V applications or with additional external resistance in series with the supply pin for greater protection against high-voltage transient events. 3-pin SOT23W (suffix LH) (A1120) (A1121, A1122, A1123, and A1125) 3-pin SIP (suffix UA) Not to scale For the A1120, A1121, A1122, and A1123, a south pole of sufficient strength turns the output on. Removal of the magnetic field turns the output off. The A1125 is complementary, in that for these devices, a south pole turns the A1125 output off, and removal of the magnetic field turns the output on. Two package styles provide a magnetically optimized package for most applications. Package type LH is a modified SOT23W, surface-mount package, while UA is a three-lead ultra-mini SIP for through-hole mounting. Each package type is lead (Pb) free (suffix, –T), with a 100% matte-tin-plated leadframe. Functional Block Diagram VCC Amp Sample and Hold Dynamic Offset Cancellation Regulator Low-Pass Filter To All Subcircuits VOUT Control Current Limit GND A1120-DS, Rev. 16 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Selection Guide Part Number Packing1 Mounting A1120ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1120ELHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1120EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1120LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1120LLHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1120LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1121ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1121ELHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1121EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1121LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1121LLHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1121LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1122ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1122ELHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1122EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1122LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1122LLHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1122LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1123LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1123LLHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1123LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1125ELHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1125ELHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1125EUA-T Bulk, 500 pieces/bag 3-pin SIP through hole A1125LLHLX-T 13-in. reel, 10000 pieces/reel 3-pin SOT23W surface mount A1125LLHLT-T2 7-in. reel, 3000 pieces/reel 3-pin SOT23W surface mount A1125LUA-T Bulk, 500 pieces/bag 3-pin SIP through hole Ambient, TA Switchpoints (Typ.) BOP BRP 35 25 95 70 Output In South (Positive) Magnetic Field –40ºC to 85ºC –40ºC to 150ºC –40ºC to 85ºC On (logic low) –40ºC to 150ºC –40ºC to 85ºC 150 125 280 225 35 25 –40ºC to 150ºC –40ºC to 150ºC –40ºC to 85ºC Off (logic high) –40ºC to 150ºC 1 Contact Allegro for additional packing options. 2 Available through authorized Allegro distributors only. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Absolute Maximum Ratings Rating Units Forward Supply Voltage Characteristic Symbol VCC Notes 26.5 V Reverse Supply Voltage VRCC –30 V Output Off Voltage VOUT 26 V Continuous Output Current IOUT 25 mA Reverse Output Current IROUT –50 mA Range E –40 to 85 ºC Range L –40 to 150 ºC TJ(max) 165 ºC Tstg –65 to 170 ºC Operating Ambient Temperature TA Maximum Junction Temperature Pin-Out Diagrams GND Storage Temperature 3 Terminal List Name VCC VOUT GND Description Connects power supply to chip Output from circuit Ground 1 2 3 GND VOUT 2 VCC 1 VOUT Package UA VCC Package LH Number Package LH Package UA 1 1 2 3 3 2 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches ELECTRICAL CHARACTERISTICS: Valid over full operating voltage and ambient temperature ranges, unless otherwise noted Characteristics Symbol Test Conditions Min. Typ.1 Max. Unit2 3 – 24 V Electrical Characteristics Forward Supply Voltage Output Leakage Current Output Saturation Voltage Output Current Limit VCC IOUTOFF VOUT(SAT) IOM Power-On Time3 tPO Operating, TJ < 165°C A1120 A1121 A1122 A1123 VOUT = 24 V, B < BRP – – 10 µA A1125 VOUT = 24 V, B > BOP – – 10 µA A1120 A1121 A1122 A1123 IOUT = 20 mA, B > BOP – 185 500 mV A1125 IOUT = 20 mA, B < BRP – 185 500 mV A1120 A1121 A1122 A1123 B > BOP 30 – 60 mA A1125 B < BRP 30 – 60 mA – – 25 µs VCC > 3.0 V, B < BRP(min) – 10 G, B > BOP(max) + 10 G Chopping Frequency fC – 800 – kHz Output Rise Time3,4 tr RL = 820 Ω, CS = 20 pF – 0.2 2 µs Output Fall Time3,4 tf RL = 820 Ω, CS = 20 pF – 0.1 2 µs ICC(ON) Supply Current ICC(OFF) Reverse Supply Current IRCC A1120 A1121 A1122 A1123 VCC = 12 V, B > BOP – – 4 mA A1125 VCC = 12 V, B < BRP – – 4 mA A1120 A1121 A1122 A1123 VCC = 12 V, B < BRP – – 4 mA A1125 VCC = 12 V, B > BOP – – 4 mA VRCC = –30 V – – –5 mA Supply Zener Clamp Voltage VZ ICC = 5 mA; TA = 25°C 28 – – V Zener Impedance IZ ICC = 5 mA; TA = 25°C – 50 – Ω Continued on the next page… Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches ELECTRICAL CHARACTERISTICS (continued): Valid over full operating voltage and ambient temperature ranges, unless otherwise noted Characteristics Max. Unit2 35 50 G 95 135 G 120 150 200 G A1123 205 280 355 G A1125 – 35 50 G A1120 5 25 – G A1121 40 70 110 G A1122 110 125 190 G A1123 150 225 300 G Symbol Test Conditions Min. Typ.1 A1120 – A1121 50 A1122 Magnetic Characteristics Operate Point Release Point BOP BRP A1125 5 25 – G A1120 – 10 – G 10 25 42 G 10 25 42 G A1123 30 55 80 G A1125 – 10 – G A1121 Hysteresis BHYS A1122 (BOP – BRP) 1 Typical data are are at TA = 25°C and VCC = 12 V, and are for initial design estimations only. 2 1 G (gauss) = 0.1 mT (millitesla). 3 Guaranteed by device design and characterization. 4 C = oscilloscope probe capacitance. S Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information Characteristic Symbol Test Conditions RθJA Maximum Allowable VCC (V) Package Thermal Resistance 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 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, 2-layer PCB (RθJA = 110 ºC/W) Package UA, 1-layer PCB (RθJA = 165 ºC/W) Package LH, 1-layer PCB (RθJA = 228 ºC/W) VCC(min) 20 40 60 80 100 120 140 160 180 Power Dissipation, PD (mW) Temperature (ºC) 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 Pa (R cka ge θJ A = L 11 H, 2 0 º -la Pac C/ ye W (R kage ) r PC UA θJA = B 165 , 1-la y ºC/ W) er PC B Pac k (R age LH , θJA = 228 1-laye ºC/W r PC B ) 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 6 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Characteristic Performance A1120, A1121, A1122, A1123, and A1125 Electrical Characteristics Average Supply Current (On) versus Ambient Temperature Average Supply Current (On) versus Average Supply Voltage 6.0 6.0 5.5 5.5 5.0 5.0 4.5 4.0 VCC (V) 3.5 2.5 3.0 12 24 2.0 A112x* 1.5 A1123 3.0 1.0 ICC(av) (mA) ICC(av) (mA) 4.5 –40 25 150 A112x* 3.0 2.5 2.0 A1123 1.0 *A1120, A1121, A1122, and A1125 0.5 0 0 - 60 3.5 1.5 *A1120, A1121, A1122, and A1125 0.5 TA (°C) 4.0 - 40 - 20 0 20 40 60 80 2 100 120 140 160 6 10 TA (°C) Average Supply Current (Off) versus Ambient Temperature 6.0 5.5 5.0 5.0 VCC (V) 4.0 3.5 2.5 3.0 12 24 2.0 A112x* 1.5 A1123 3.0 1.0 ICC(av) (mA) ICC(av) (mA) 26 4.5 4.5 TA (°C) 4.0 3.5 –40 25 150 A112x* 3.0 2.5 2.0 A1123 1.5 1.0 *A1120, A1121, A1122, and A1125 0.5 *A1120, A1121, A1122, and A1125 0.5 0 0 - 40 - 20 0 20 40 60 80 2 100 120 140 160 6 10 TA (°C) 14 18 22 26 VCC (V) Average Output Saturation Voltage versus Supply Voltage Average Output Saturation Voltage versus Ambient Temperature 300 300 250 250 VCC (V) 3.0 3.8 4.2 12 24 200 150 100 A112x* A1123 50 *A1120, A1121, A1122, and A1125 0 - 40 - 20 0 20 40 60 TA (°C) 80 100 120 140 160 VOUT(sat) (V) VOUT(sat) (V) 22 Average Supply Current (Off) versus Average Supply Voltage 5.5 - 60 18 VCC (V) 6.0 - 60 14 200 TA (°C) –40 25 150 A112x* 150 100 A1123 50 *A1120, A1121, A1122, and A1125 0 2 6 10 14 18 22 26 VCC (V) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches A1120 and A1125 Magnetic Characteristics Average Operate Point versus Ambient Temperature 50 50 45 45 40 40 VCC (V) 30 3.0 25 24 20 35 BOP (G) 35 BOP (G) Average Operate Point versus Average Supply Voltage –40 25 25 150 20 15 15 10 10 5 5 0 TA (°C) 30 0 -60 -40 -20 0 20 40 60 80 100 120 140 160 2 6 10 TA (°C) 22 26 Average Release Point versus Average Supply Voltage 50 50 45 45 40 40 35 35 30 VCC (V) 25 3.0 20 BRP (G) BRP (G) 18 VCC (V) Average Release Point versus Ambient Temperature 24 15 30 TA (°C) 25 –40 20 25 15 150 10 10 5 5 0 0 -60 -40 -20 0 20 40 60 80 2 100 120 140 160 6 10 TA (°C) 14 18 22 26 VCC (V) Average Switchpoint Hysteresis versus Supply Voltage Average Switchpoint Hysteresis versus Ambient Temperature 20 20 18 18 16 16 14 12 VCC (V) 10 3.0 8 24 BHYS (G) BHYS (G) 14 14 12 TA (°C) 10 –40 25 8 6 6 4 4 2 2 150 0 0 -60 -40 -20 0 20 40 60 TA (°C) 80 100 120 140 160 2 6 10 14 18 22 26 VCC (V) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches A1121 Magnetic Characteristics Average Operate Point versus Average Supply Voltage 140 140 130 130 120 120 110 VCC (V) 100 3.0 12 24 90 80 BOP (G) BOP (G) Average Operate Point versus Ambient Temperature 110 TA (°C) 100 –40 25 90 150 80 70 70 60 60 50 - 60 - 40 - 20 50 0 20 40 60 80 100 120 140 160 2 6 10 TA (°C) 110 100 100 90 90 80 VCC (V) 70 3.0 12 24 BRP (G) BRP (G) 22 26 Average Release Point versus Average Supply Voltage 110 60 TA (°C) 80 –40 70 25 150 60 50 50 - 60 - 40 - 20 0 20 40 60 80 40 100 120 140 160 2 6 10 TA (°C) 18 22 26 Average Switchpoint Hysteresis versus Supply Voltage 40 35 35 30 VCC (V) 3.0 12 24 25 20 15 BHYS (G) 40 10 - 60 - 40 - 20 14 VCC (V) Average Switchpoint Hysteresis versus Ambient Temperature BHYS (G) 18 VCC (V) Average Release Point versus Ambient Temperature 40 14 30 TA (°C) 25 –40 20 150 25 15 0 20 40 60 TA (°C) 80 100 120 140 160 10 2 6 10 14 18 22 26 VCC (V) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches A1122 Magnetic Characteristics Average Operate Point versus Ambient Temperature Average Operate Point versus Average Supply Voltage 200 200 190 190 180 VCC (V) 170 3.0 12 24 160 150 BOP (G) BOP (G) 180 –40 160 25 150 150 140 140 130 130 120 - 60 - 40 - 20 TA (°C) 170 120 0 20 40 60 80 100 120 140 160 2 6 10 TA (°C) 180 170 170 160 VCC (V) 150 3.0 12 24 140 BRP (G) BRP (G) 190 180 TA (°C) 150 –40 130 120 60 80 25 140 120 40 110 100 120 140 160 150 2 6 10 TA (°C) 18 22 26 Average Switchpoint Hysteresis versus Supply Voltage 40 40 35 35 30 VCC (V) 3.0 12 24 25 20 BHYS (G) BHYS (G) 14 VCC (V) Average Switchpoint Hysteresis versus Ambient Temperature 30 TA (°C) 25 –40 20 150 25 15 15 10 - 60 - 40 - 20 26 160 130 20 22 Average Release Point versus Average Supply Voltage 190 0 18 VCC (V) Average Release Point versus Ambient Temperature 110 - 60 - 40 - 20 14 0 20 40 60 TA (°C) 80 100 120 140 160 10 2 6 10 14 18 22 26 VCC (V) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches A1123 Magnetic Characteristics Average Operate Point versus Ambient Temperature 355 355 350 350 TA (°C) 3 280 12 24 255 TA (°C) 305 BOP (G) 305 BOP (G) Average Operate Point versus Average Supply Voltage –40 280 25 150 255 230 230 205 205 -60 -40 -20 0 20 40 60 80 100 120 140 160 2 6 10 TA (°C) 22 26 Average Release Point versus Average Supply Voltage 300 300 275 275 250 TA (°C) 225 3 12 200 BRP (G) BRP (G) 18 VCC (V) Average Release Point versus Ambient Temperature 24 175 250 TA (°C) 225 –40 200 150 25 175 150 150 -60 -40 -20 0 20 40 60 80 2 100 120 140 160 6 10 TA (°C) 14 18 22 26 VCC (V) Average Switchpoint Hysteresis versus Supply Voltage Average Switchpoint Hysteresis versus Ambient Temperature 80 80 75 75 70 70 65 65 60 TA (°C) 55 3 12 50 24 45 BHYS (G) BHYS (G) 14 60 TA (°C) 55 –40 150 45 40 40 35 35 30 25 50 30 -60 -40 -20 0 20 40 60 TA (°C) 80 100 120 140 160 2 6 10 14 18 22 26 VCC (V) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 11 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Functional Description Operation The output of the A1120, A1121, A1122, and A1123 devices switches low (turns on) when a magnetic field perpendicular to the Hall element exceeds the operate point threshold, BOP (see panel A of figure 1). When the magnetic field is reduced below the release point, BRP , the device output goes high (turns off). The output of the A1125 devices switches high (turns off) when a magnetic field perpendicular to the Hall element exceeds the operate point threshold, BOP (see panel B of figure 1). When the magnetic field is reduced below the release point, BRP , the device output goes low (turns on). After turn-on, the output voltage is VOUT(SAT) . The output transistor is capable of sinking current up to the short circuit current limit, IOM, which is a minimum of 30 mA. 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. Powering-on the device in the hysteresis range (less than BOP and higher than BRP) will BRP B+ • Hall-Effect IC Applications Guide, Application Note 27701 • Guidelines for Designing Subassemblies Using Hall-Effect Devices, Application Note 27703.1 • Soldering Methods for Allegro’s Products – SMT and ThroughHole, Application Note 26009 All are provided on the Allegro Web site, www.allegromicro.com. 0 Switch to High VCC 0 BHYS BHYS (A) (B) RL A112x VOUT VOUT(SAT) BOP BOP 0 Extensive applications information for Hall effect devices is available in: VCC VOUT VOUT VOUT(SAT) It is strongly recommended that an external bypass capacitor be connected (in close proximity to the Hall element) between the supply and ground of the device to reduce external noise in the application. As is shown in panel B of figure 1, a 0.1 µF capacitor is typical. VS Switch to Low 0 Switch to Low Switch to High VCC Applications V+ BRP V+ give an indeterminate output state. The correct state is attained after the first excursion beyond BOP or BRP . CBYP 0.1 µF Output GND B+ (C) Figure 1. Device switching behavior. In panels A and B, on the horizontal axis, the B+ direction indicates increasing south polarity magnetic field strength. This behavior can be exhibited when using an electrical circuit such as that shown in panel C. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Chopper Stabilization Technique When using Hall effect technology, a limiting factor for switchpoint accuracy is the small signal voltage developed across the Hall element. This voltage is disproportionally small relative to the offset that can be produced at the output of the Hall element. This makes it difficult to process the signal while maintaining an accurate, reliable output over the specified operating temperature and voltage ranges. Chopper stabilization is a unique approach used to minimize Hall offset on the chip. The patented Allegro technique, namely Dynamic Quadrature Offset Cancellation, removes key sources of the output drift induced by thermal and mechanical stresses. This offset reduction technique is based on a signal modulationdemodulation process. The undesired offset signal is separated from the magnetic field-induced signal in the frequency domain, through modulation. The subsequent demodulation acts as a modulation process for the offset, causing the magnetic field induced signal to recover its original spectrum at baseband, while the dc offset becomes a high-frequency signal. The magnetic sourced signal then can pass through a low-pass filter, while the modulated DC offset is suppressed. This configuration is illustrated in figure 2. The chopper stabilization technique uses a 400 kHz high frequency clock. For demodulation process, a sample and hold technique is used, where the sampling is performed at twice the chopper frequency (800 kHz). This high-frequency operation allows a greater sampling rate, which results in higher accuracy and faster signal-processing capability. This approach desensitizes the chip to the effects of thermal and mechanical stresses, and produces devices that have extremely stable quiescent Hall output voltages and precise recoverability after temperature cycling. This technique is made possible through the use of a BiCMOS process, which allows the use of low-offset, low-noise amplifiers in combination with high-density logic integration and sample-and-hold circuits. The repeatability of magnetic field-induced switching is affected slightly by a chopper technique. However, the Allegro high frequency chopping approach minimizes the affect of jitter and makes it imperceptible in most applications. Applications that are more likely to be sensitive to such degradation are those requiring precise sensing of alternating magnetic fields; for example, speed sensing of ring-magnet targets. For such applications, Allegro recommends its digital device families with lower sensitivity to jitter. For more information on those devices, contact your Allegro sales representative. Regulator Hall Element Amp Sample and Hold Clock/Logic Low-Pass Filter Figure 2. Model of chopper stabilization technique Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 13 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches 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 website.) 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 = 1.6 mA, and RθJA = 165 °C/W, then: 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 LH, using a minimum-K PCB. Observe the worst-case ratings for the device, specifically: RθJA = 228°C/W, TJ(max) = 165°C, VCC(max) = 24 V, and ICC(max) = 4 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 ÷ 228 °C/W = 66 mW Finally, invert equation 1 with respect to voltage: VCC(est) = PD(max) ÷ ICC(max) = 66 mW ÷ 4 mA = 16.5 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. PD = VCC × ICC = 12 V × 1.6 mA = 19 mW ΔT = PD × RθJA = 19 mW × 165 °C/W = 3°C TJ = TA + ΔT = 25°C + 3°C = 28°C Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 14 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Package LH, 3-Pin (SOT-23W) +0.12 2.98 –0.08 1.49 D 4°±4° 3 A +0.020 0.180–0.053 0.96 D +0.10 2.90 –0.20 +0.19 1.91 –0.06 2.40 0.70 D 0.25 MIN 1.00 2 1 0.55 REF 0.25 BSC 0.95 Seating Plane Gauge Plane 8X 10° REF B PCB Layout Reference View C Standard Branding Reference View Branded Face 1.00 ±0.13 0.95 BSC 0.40 ±0.10 For Reference Only; not for tooling use (reference dwg. 802840) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Active Area Depth, 0.28 mm REF 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 C Branding scale and appearance at supplier discretion D Hall element, not to scale NNT +0.10 0.05 –0.05 1 N = Last two digits of device part number T = Temperature code (letter) NNN 1 N = Last three digits of device part number Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 15 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Package UA, 3-Pin SIP (A1120) +0.08 4.09 –0.05 45° B C E 2.04 1.52 ±0.05 1.44 E Mold Ejector Pin Indent +0.08 3.02 –0.05 E Branded Face 45° 1 2.16 MAX D Standard Branding Reference View = Supplier emblem N = Last two digits of device part number T = Temperature code 0.79 REF 0.51 REF NNT A 1 2 3 +0.03 0.41 –0.06 15.75 ±0.51 For Reference Only; not for tooling use (reference DWG-9049) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown A Dambar removal protrusion (6X) B Gate burr area C Active Area Depth, 0.50 mm REF +0.05 0.43 –0.07 D Branding scale and appearance at supplier discretion E Hall element, not to scale 1.27 NOM Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 16 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Package UA, 3-Pin SIP (A1121, A1122, A1123, and A1125) +0.08 4.09 –0.05 45° B E C 2.04 1.52 ±0.05 +0.08 3.02 –0.05 1.44 E 10° Mold Ejector Pin Indent E Branded Face A 1.02 MAX 45° 0.79 REF NNN 1 1 2 D Standard Branding Reference View 3 = Supplier emblem N = Last three digits of device part number +0.03 0.41 –0.06 14.99 ±0.25 +0.05 0.43 –0.07 For Reference Only; not for tooling use (reference DWG-9065) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 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) 1.27 NOM Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 17 A1120, A1121, A1122, A1123, and A1125 Chopper-Stabilized Precision Hall-Effect Switches Revision History Revision Revision Date Description of Revision 15 September 3, 2013 Update product offerings Update UA package drawing 16 September 16, 2015 Added AEC-Q100 qualification under Features and Benefits Copyright ©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. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 18