Continuous-Time Switch Family

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Features and Benefits Continuous-time operation Fast power-on time Low noise Stable operation over full operating temperature range Reverse battery protection Solid-state reliability

1 Features and Benefits 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 (suffix LH), and 3-pin SIP (suffix UA) Description The Allegro A-A4 and A6 Hall-effect switches are next generation replacements for the popular Allegro 32x and 34x lines of unipolar switches. The Ax family, produced with BiCMOS technology, consists of 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 lowoffset amplifiers help to minimize noise and to reduce the residual offset voltage normally caused by device overmolding, temperature excursions, and thermal stress. The A-A4 and A6 Hall-effect 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 ±3 V absolute maximum voltage rating for superior protection in automotive and industrial motor commutation applications, without adding LH: A, A2, A3, Not to scale UA: A, A2, A3, and A4 UA: A6 Continued on the next page Functional Block Diagram VCC Regulator To all subcircuits VOUT Amp Gain Offset Trim Control GND A-DS, Rev. 5

2 Description (continued) external components. All devices in the family are identical except for magnetic switchpoint levels. 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 an SOT23W, a miniature low-profile surface-mount package, while package UA is a three-lead ultramini SIP for throughhole mounting. Each package is lead (Pb) free, with % matte tin plated leadframes. Selection Guide Part Number Packing * Mounting Ambient, T A B RP (Min) B OP (Max) AELHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount AEUA-T Bulk, 5 pieces/bag 3-pin SIP through hole 4ºC to 85ºC ALLHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount ALUA-T Bulk, 5 pieces/bag 3-pin SIP through hole 4ºC to 5ºC 75 A2ELHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount A2EUA-T Bulk, 5 pieces/bag 3-pin SIP through hole 4ºC to 85ºC A2LLHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount A2LUA-T Bulk, 5 pieces/bag 3-pin SIP through hole 4ºC to 5ºC A3ELHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount 4ºC to 85ºC A3LLHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount ºC to 5ºC A3LUA-T Bulk, 5 pieces/bag 3-pin SIP through hole A4EUA-T Bulk, 5 pieces/bag 3-pin SIP through hole 4ºC to 85ºC A4LLHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount ºC to 5ºC A4LUA-T Bulk, 5 pieces/bag 3-pin SIP through hole A6EUA-T Bulk, 5 pieces/bag 3-pin SIP through hole 4ºC to 85ºC A6LLHLT-T 7-in. reel, 3 pieces/reel 3-pin SOT23W surface mount ºC to 5ºC A6LUA-T Bulk, 5 pieces/bag 3-pin SIP through hole *Contact Allegro for additional packing options. Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage V CC 3 V Reverse Supply Voltage V RCC 3 V Output Off Voltage V OUT 3 V Reverse Output Voltage V ROUT.5 V Output Current I OUTSINK 25 ma Magnetic Flux Density B Unlimited G Operating Ambient Temperature T A Range E 4 to 85 ºC Range L 4 to 5 ºC Maximum Junction Temperature T J (max) 65 ºC Storage Temperature T stg 65 to 7 ºC 2

3 ELECTRICAL OPERATING CHARACTERISTICS over full operating voltage and ambient temperature ranges, unless otherwise noted Characteristic Symbol Test Conditions Min. Typ. Max. Units Supply Voltage V CC Operating, T J < 65 C V Output Leakage Current I OUTOFF V OUT = 24 V, B < B RP µa Output On Voltage V OUT(SAT) I OUT = 2 ma, B > B OP 25 4 mv Power-On Time 2 t PO Slew rate (dv CC /dt) < 2.5 V/μs, B > B OP + 5 G or B < B RP 5 G 4 µs Output Rise Time 3 t r V CC = 2 V, R LOAD = 82 Ω, C S = 2 pf 4 ns Output Fall Time 3 t f V CC = 2 V, R LOAD = 82 Ω, C S = 2 pf 4 ns Supply Current I CCON B > B OP ma I CCOFF B < B RP ma Reverse Battery Current I RCC V RCC = 3 V ma Supply Zener Clamp Voltage V Z I CC =.5 ma; T A = 25 C 32 V Supply Zener Current 4 I Z V Z = 32 V; T A = 25 C.5 ma Maximum voltage must be adjusted for power dissipation and junction temperature, see Power Derating section. 2 For V CC slew rates greater than 25 V/μs, and T A = 5 C, the Power-On Time can reach its maximum value. 3 C S =oscilloscope probe capacitance. 4 Maximum current limit is equal to the maximum I CC(max) + 3 ma. DEVICE QUALIFICATION PROGRAM Contact Allegro for information. EMC (Electromagnetic Compatibility) REQUIREMENTS Contact Allegro for information. Package LH Package UA, 3-pin SIP VCC VCC GND VOUT GND VOUT Terminal List Name Description Number Package LH Package UA VCC Connects power supply to chip VOUT Output from circuit 2 3 GND Ground 3 2 3

4 MAGNETIC OPERATING CHARACTERISTICS over full operating voltage and ambient temperature ranges, unless otherwise noted Characteristic Symbol Test Conditions Min. Typ. Max. Units Operate Point Release Point Hysteresis B OP B RP B HYS A A2 A3 A4 A6 A A2 A3 A4 A6 A A2 A3 A4 A6 T A = 25 C 5 6 G Operating Temperature Range 3 75 G T A = 25 C G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C 7 35 G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C 45 3 G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C 5 33 G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C G Operating Temperature Range G T A = 25 C 2 55 G Operating Temperature Range 2 55 G T A = 25 C G Operating Temperature Range G 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 G field and a G field have equivalent strength, but opposite polarity). 4

5 Characteristic Symbol Test Conditions Value Units Package Thermal Resistance R θja Package LH, -layer PCB with copper limited to solder pads 228 ºC/W Package LH, 2-layer PCB with.463 in. 2 of copper area each side connected by thermal vias ºC/W Package UA, -layer PCB with copper limited to solder pads 65 ºC/W Maximum Allowable V CC (V) Power Derating Curve T J(max) = 65ºC; I CC = I CC(max) Package LH, 2-layer PCB (R θja = ºC/W) Package UA, -layer PCB (R θja = 65 ºC/W) Package LH, -layer PCB (R θja = 228 ºC/W) V CC(max) V CC(min) Power Dissipation, PD (mw) Power Dissipation versus Ambient Temperature Package LH, 2-layer PCB (R θja = ºC/W) Package UA, -layer PCB (R θja = 65 ºC/W) Package LH, -layer PCB (R θja = 228 ºC/W) Temperature ( C) 5

6 Characteristic Data Supply Current (On) versus Ambient Temperature (A/2/3/4/6) Supply Current (On) versus Supply Voltage (A/2/3/4/6) ICCON (ma) V CC (V) T A ( C) V CC (V) ICCON (ma) T A ( C) Supply Current (Off) versus Ambient Temperature (A/2/3/4/6) Supply Current (Off) versus Supply Voltage (A/2/3/4/6) ICCOFF (ma) V CC (V) 6. T A ( C) T A ( C) V CC (V) ICCOFF (ma) Output Voltage (On) versus Ambient Temperature (A/2/3/4/6) 4 4 Output Voltage (On) versus Supply Voltage (A/2/3/4/6) V OUT(SAT) (mv) V CC (V) VOUT(SAT) (mv) T A ( C) T A ( C) V CC (V) 6

7 Functional Description OPERATION The output of these devices switches low (turns on) when a magnetic field (south polarity) perpendicular to the Hall element exceeds the operate point threshold, B OP. After turn-on, the output is capable of sinking 25 ma and the output voltage is V OUT(SAT). When the magnetic field is reduced below the release point, B RP, the device output goes high (turns off). The difference in the magnetic operate and release points is the hysteresis, B hys, 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 region, less than B OP and higher than B RP, allows an indeterminate output state. The correct state is attained after the first excursion beyond B OP or B RP. CONTINUOUS-TIME BENEFITS Continuous-time devices, such as the Ax 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. 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, V CC 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, t PO, 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 the chopper stabilization technique, refer to Technical Paper STP 97-, Monolithic Magnetic Hall Sensing Using Dynamic Quadrature Offset Cancellation and Technical Paper STP 99-, Chopper-Stabilized Amplifiers with a Track-and-Hold Signal Demodulator. (A) (B) V OUT V+ B Switch to High B RP B OP Switch to Low B+ V CC V OUT(SAT) V S VCC Ax VOUT GND R L Output B HYS Figure. Switching Behavior of Unipolar 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). This behavior can be exhibited when using a circuit such as that shown in Panel B. 7

8 ADDITIONAL APPLICATIONS INFORMATION Extensive applications information for Hall-effect devices is available in: Hall-Effect IC Applications Guide, Application Note 277 Hall-Effect Devices: Gluing, Potting, Encapsulating, Lead Welding and Lead Forming, Application Note Soldering Methods for Allegro s Products SMT and Through- Hole, Application Note 269 All are provided in Allegro Electronic Data Book, AMS-72, and the Allegro Web site, V CC t V OUT t t PO(max) Output Sampled Figure 2. Continuous-Time Application, B < B RP.. This figure illustrates the use of a quick cycle for chopping V CC in order to conserve battery power. Position, power is applied to the device. Position 2, the output assumes the correct state at a time prior to the maximum Power-On Time, t PO(max). The case shown is where the correct output state is HIGH. Position 3, t PO(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. 8

9 Power Derating Power Derating The device must be operated below the maximum junction temperature of the device, T J(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 T J. (Thermal data is also available on the Allegro MicroSystems Web site.) The Package Thermal Resistance, R θja, 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, R θjc, is relatively small component of R θja. Ambient air temperature, T A, and air motion are significant external factors, damped by overmolding. The effect of varying power levels (Power Dissipation, P D ), can be estimated. The following formulas represent the fundamental relationships used to estimate T J, at P D. P D = V IN I IN () ΔT = P D R θja (2) Example: Reliability for V CC at T A = 5 C, package UA, using minimum-k PCB. Observe the worst-case ratings for the device, specifically: R θja = 65 C/W, T J(max) = 65 C, V CC(max) = 24 V, and I CC(max) = 7.5 ma. Calculate the maximum allowable power level, P D(max). First, invert equation 3: ΔT max = T J(max) T A = 65 C 5 C = 5 C This provides the allowable increase to T J resulting from internal power dissipation. Then, invert equation 2: P D(max) = ΔT max R θja = 5 C 65 C/W = 9 mw Finally, invert equation with respect to voltage: V CC(est) = P D(max) I CC(max) = 9 mw 7.5 ma = 2. V The result indicates that, at T A, the application and device can dissipate adequate amounts of heat at voltages V CC(est). Compare V CC(est) to V CC(max). If V CC(est) V CC(max), then reliable operation between V CC(est) and V CC(max) requires enhanced R θja. If V CC(est) V CC(max), then operation between V CC(est) and V CC(max) is reliable under these conditions. T J = T A + ΔT (3) For example, given common conditions such as: T A = 25 C, V CC = 2 V, I CC = 4 ma, and R θja = 4 C/W, then: P D = V CC I CC = 2 V 4 ma = 48 mw ΔT = P D R θja = 48 mw 4 C/W = 7 C T J = T A + ΔT = 25 C + 7 C = 32 C A worst-case estimate, P D(max), represents the maximum allowable power level (V CC(max), I CC(max) ), without exceeding T J(max), at a selected R θja and T A. 9

10 Package LH, 3-Pin (SOT-23W) D A 4 ± D D MIN REF.25 BSC Seating Plane Gauge Plane B.95 PCB Layout Reference View 8X REF Branded Face. ±.3 C Standard Branding Reference View A B C D.95 BSC Active Area Depth,.28 mm REF.4 ± For Reference Only; not for tooling use (reference dwg. 8284) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown Reference land pattern layout All pads a minimum of.2 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances Branding scale and appearance at supplier discretion Hall element, not to scale NNT N = Last two digits of device part number T = Temperature code (letter) NNN N = Last three digits of device part number

11 Package UA, 3-Pin SIP (A, A2, A3. and A4) B E 2.4 C.52 ± MAX.5 REF E A E Branded Face.79 REF 45 Mold Ejector Pin Indent NNT D Standard Branding Reference View = Supplier emblem N = Last two digits of device part number T = Temperature code 5.75 ± For Reference Only; not for tooling use (reference DWG-949) 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 B C D E Dambar removal protrusion (6X) Gate burr area Active Area Depth,.5 mm REF Branding scale and appearance at supplier discretion Hall element, not to scale NOM

12 Package UA, 3-Pin SIP (A6) B E 2.4 C.52 ± MAX.44 E E A Branded Face.79 REF 45 Mold Ejector Pin Indent NNT D Standard Branding Reference View = Supplier emblem N = Last two digits of device part number T = Temperature code 2 3 For Reference Only; not for tooling use (reference DWG-965) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 4.99 ± A Dambar removal protrusion (6X) B Gate and tie bar burr area C Active Area Depth,.5 mm REF D E Branding scale and appearance at supplier discretion Hall element (not to scale).27 NOM 2

13 Revision History Revision Revision Date Description of Revision Rev. 4 January 2, 24 Removed P/Ns from LH package drwg. Copyright 26-24, 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, 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: 3

Continuous-Time Switch Family

Continuous-Time Switch Family Features and enefits Continuous-time operation Fast power-on time Low noise Stable operation over full operating temperature range Reverse battery protection Solid-state reliability Factory-programmed