A8481EEJTR-T

A8481 Dual Output Boost Regulator Using Single Inductor Features and Benefits ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ Two independently controlled channels for dual display Output voltage up to 23 V 2.7 to 9 V input Output disconnect allows less than 1 μA supply current during shutdown Single-pin dimming control for WLED 1.2 MHz switching frequency 1.5 A switch current limit OVP, Pulse-by-Pulse OCP, OTP, and Soft Start Description The A8481 is a step-up dc-to-dc converter in a thermallyenhanced MLP package. A constant 1.2 MHz switching frequency, with current-mode control scheme, provides stable low-noise operation at high load conditions. The A8481 is a dual output OLED + WLED driver. This device is suitable for driving OLED bias supply as well as WLEDs for backlight. For OLED it is capable of delivering 80 mA at 18 V, and can drive five WLEDs at 20 mA. Independent output control and output disconnect make this IC ideally suited for battery operated, dual display portable applications. The IC disconnects input from the output path during shutdown, allowing shutdown currents less than 1 μA. Package: 10 pin MLP/DFN (suffix EJ) with exposed thermal pad The A8481 is available in a 10-pin 3 mm × 3 mm MLP package that has a nominal height of only 0.75 mm. Applications include: ▪ Dual-panel cellular phone with OLED and WLED backlight ▪ Personal Digital Assistant (PDA) ▪ Camcorder, personal stereo, MP3 player, camera Approximate Scale 1:1 Typical Applications Additional applications on page 11 VOUT L1 1 CIN VSUPPLY 2 3 4 5 GND FB1 VIN SW CAP 10 9 8 7 6 R1 OLED VSUPPLY D1 COUT CIN 1 2 3 4 5 GND FB1 VIN L1 SW CAP 10 9 8 7 6 R1 OLED PWM Q1 RP RSET R2 D1 COUT VOUT A8481 OUT1 ISET ON1 A8481 OUT1 ISET ON1 OUT2 ON2 OUT2 ON2 RSET R2 Figure 1a. Typical application circuit for A8481 driving OLED and three WLEDs 8481-DS, Rev. 2 Figure 1b. OUT2 current dimming with PWM on ISET pin, with parallel resistor A8481 Dual Output Boost Regulator Using Single Inductor Functional Block Diagram SW VIN S1 0.6 V C5 FB1 0.3 V C3 Select MIN and Error Amplifier Soft Start C4 R S Q Driver ∑ Ramp Oscillator Clock C1 OUT2 FB1 CAP VCAP Fault Protection C2 VREF1 On/Off Logic ISET Decoder UVLO ON1 Temp S2 OUT1 0.6 V ON2 Current Regulator IREF S3 OUT2 ISET GND Absolute Maximum Ratings Input or Output Voltage SW, CAP, OUT1, OUT2 pins ..................................–0.3 to 26 V VIN pin, VIN ............................................................–0.3 to 9.5 V All other pins, Vx ....................... –0.3 to VIN + 0.3 V (7 V max.) Operating Ambient Temperature, TA ................................ –40°C to 85°C Maximum Junction Temperature, TJ(max) ...................................... 150°C Storage Temperature, TS .............................................. –55°C to 150°C Package Thermal Characteristics RθJA = 45 °C/W, on a 4-layer board. Additional information is available on the Allegro Web site. Ordering Information Use the following complete part numbers when ordering: Part Number A8481EEJTR-Tb aContact Allegro bLead Packinga 7-in. reel, 1500 pieces/reel Description EJ package, MLP/DFN(SON) leadless surface mount with exposed thermal pad for additional packing options. (Pb) free, with leadframe plating 100% matte tin. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 A8481 Dual Output Boost Regulator Using Single Inductor Pin-out Diagram GND FB1 VIN OUT2 ON2 1 2 3 4 5 PAD 10 9 8 7 6 SW CAP OUT1 ISET ON1 (Top View) Number 1 2 3 4 5 6 7 8 9 10 – Name GND FB1 VIN OUT2 ON2 ON1 ISET OUT1 CAP SW Pad Description Power ground and signal ground reference; connect directly to the ground plane. This is the feedback pin for controlling voltage on the OUT1 pin. The nominal reference voltage on this pin is 600 mV. In order to minimize noise, connect the feedback resistor network close to this pin. This is the power input supply connection to the circuit. A bypass capacitor tying this pin to GND must be connected close to this pin. This is the current sink pin for the WLED supply. The load current through this pin can be controlled through the ISET pin or the ON2 pin. This is the enable pin for OUT2. This pin is also used for the serial input interface to control the OUT2 current. This is the enable pin for OUT1. This pin is used to set load current through the OUT2 pin. This is the voltage-controlled pin for the OLED drive. An internal switch disconnects the OLED during shutdown. This is the connection to the output capacitor for the boost regulator output. This is the connection between the internal boost switch and the external inductor. Because rapid changes of current occur at this pin, the board traces connected to this pin should be minimized and the inductor and diode should be connected as close to this pin as possible. Exposed thermal pad. Connect to GND plane for enhanced thermal performance. Operation State Control Truth Table Pin ON1 0 0 1 1 ON2 0 1 0 1 State Description IC shutdown. Total input current from VIN is < 1 μA. OUT2 on, OUT1 off. Boost stage is controlled to regulate OUT2 current with switch S2 off. OUT1 on, OUT2 off. Boost stage is controlled to regulate OUT1 voltage and to turn switch S3 off. OUT2 and OUT1 on. Boost stage is controlled such that voltage on the CAP pin is sufficient to bias OUT1 and OUT2. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A8481 Dual Output Boost Regulator Using Single Inductor ELECTRICAL CHARACTERISTICS at TA = 25°C, VIN = ON1 = ON2 = 3.0 V, RSET = 30 kΩ (unless noted otherwise) Characteristics Input Voltage Range Undervoltage Lockout Threshold Feedback Reference Voltage Feedback Voltage Line Regulation Feedback Input Current Switch Current Limit Switch Frequency Switch Maximum Duty Cycle* Switch S1 On Resistance Switch Leakage Current Quiescent Input Current ON1, ON2 Logic Input Levels Input Threshold Low Input Threshold High Input Leakage Overvoltage Protection Output Overvoltage Rising Limit ISET to IOUT2 Current Gain ISET Pin Voltage ISET Current Range ON2 Serial Pulse Timing ON2 Pulse Low Time ON2 Pulse High Time Initial ON2 Pulse High Time Shut Down Delay Thermal Shutdown Threshold Thermal Shutdown Hysteresis Soft-Start Period *Guaranteed by design. tLO tHI tHII tSHDN TSHDN TSHDNhys tSS VOUT = 10 V First ON2 pulse after shutdown Falling edge on ON2 0.5 0.5 1 – – – – – – – 1 160 10 2 20 – – 2 – – – μs μs ms ms (°) (°) ms VOVPR ASET VSET ISET ISET = 10 μA – 890 – 1 24.5 1000 0.6 – 25.5 1110 – 20 V A/A V μA VIL VIH IL – 1.5 – – – 65 0.4 – – V V μA IFB ISWLim fSW DC RDS1(on) ILSW IIN(Q) ISW = 0.5 A VSW = 5 V ON1 = ON2 = 0 V Symbol VIN VUVLO VFB 2.7 V ≤ VIN ≤ 9 V VIN rising Test Conditions Min. 2.7 2.25 584 – – – 1 85 – – – Typ. – 2.45 610 0.1 45 1.5 1.2 90 225 – – Max. 9 2.60 636 – 100 – 1.4 – – 1 1 Units V V mV %/V nA A MHz % mΩ μA μA Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 A8481 Dual Output Boost Regulator Using Single Inductor Tests performed using application circuit shown in figure 1(a) L1 = 4.7 μH, CIN = COUT = 1 μF, TA = 25°C, VIN = 3 V (unless otherwise noted) Performance Characteristics Efficiency with OUT1 off, OUT2 on, 5 WLEDs Over range of dimming levels, LED voltage drop at 20 mA = 16.3 V 85 80 20 mA (Full Brightness) 75 12 mA 70 η (%) 65 60 55 50 45 2 4 4 mA Dimming Level (mA) 6 VIN (V) 8 10 Efficiency with OUT2 on, OUT1 off, 3 WLEDs Over range of dimming levels, LED voltage drop at 20 mA = 9 V 85 80 75 70 20 mA (Full Brightness) 12 mA η (%) 4 mA 65 60 55 50 45 2 4 6 VIN (V) Dimming Level (mA) 8 10 Efficiency with OUT1 on, OUT2 off VOUT1= 16 V 85 80 mA 60 mA 80 40 mA 20 mA 75 10 mA η (%) 70 Dimming Level 80 mA = Full Brightness 65 3 mA 60 55 2 4 6 VIN (V) 8 10 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 A8481 Dual Output Boost Regulator Using Single Inductor Tests performed using application circuit shown in figure 1(a) L1 = 4.7 μH, CIN = COUT = 1 μF, TA = 25°C, VIN = 3 V (unless otherwise noted) Performance Characteristics OLED Line Regulation VOUT1= 16 V 16.25 16.20 16.15 16.25 16.20 OLED Load Regulation VOUT1= 16 V Dimming Level 80 mA = Full Brightness 16.15 16.10 80 mA VOUT (V) 60 mA 16.05 16.00 15.95 15.90 15.85 2 4 6 VIN (V) 8 10 VOUT (V) 16.10 8.5 V 7V 16.05 16.00 15.95 15.90 40 mA 20 mA 1 mA 10 mA 3 mA 5V 4V 3.6 V 3V 2.7 V Supply Level, VIN 15.85 0 20 40 IOUT (mA) 60 80 WLED Startup, 5 LEDs, 20 mA VON2 C1 C1 OLED Startup, 18 V, 80 mA VON1 C2 ILED C2 VOUT1 C3 IIN C3 IIN t t Symbol C1 C2 C3 t Parameter VON2 ILED IIN time Units/Division 5V 10.0 mA 50 mA 5 ms Symbol C1 C2 C3 t Parameter VON1 VOUT1 IIN time Units/Division 5V 5V 500 mA 5 ms Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 A8481 Dual Output Boost Regulator Using Single Inductor Tests performed using application circuit shown in figure 1(a) L1 = 4.7 μH, CIN = COUT = 1 μF, TA = 25°C, VIN = 3 V (unless otherwise noted) Performance Characteristics OLED (18 V, 80 mA) and WLED (5 LEDs, 20 mA) Simultaneous startup and shutdown Symbol C1 C2 C3 C4 t Parameter VOUT1 VCAP VOUT2 IIN time Units/Division 3V 3V 3V 200 mA 5 ms VOUT1 VCAP IIN IIN C4 VOUT2 VCAP VOUT1 , VOUT2 C1, C3 C2 t Serial Dimming Using ON2 20 VON2 18 16 14 IOUT2 (mA) C1 12 10 8 6 4 2 IOUT2 C2 t 0 0 1 2 3 4 5 6 7 Step Sequence on Pin ON2 Symbol C1 C2 t Parameter VON2 IOUT2 time Units/Division 1V 10 mA 5 ms Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 A8481 Dual Output Boost Regulator Using Single Inductor Functional Description The A8481 is a dual output converter with two-stage architecture. The first stage is a boost stage, which boosts input battery voltage to a sufficient level to drive an OLED or a set of series-connected WLEDs. This stage uses 1.2 MHz constant frequency, current mode control. Typical application circuits are shown in figures 1 and 4. The constant voltage drive for OLED is provided through the OUT1 pin. The internal switch S2, connected between the CAP and OUT1 pins, acts as either a switch or as a linear regulator when OUT1 is on. Switch S2 disconnects the OLED when OUT1 is disabled. For driving OLEDs, output voltage is sensed by the FB1 pin through a voltage divider network. Output voltage (V) is set as: R1 + R2 VOUT1 = 0.6 × (1) R 2 During normal operation, if both outputs are enabled and one output is out of regulation, that output will control the boost loop. The corresponding output switch will completely turn on and the other output switch will linearly regulate. For example: • Case A. If the current through the OUT2 pin falls below 95% of the set value (ISET multiplied by internal gain), the boost stage will be controlled by OUT2, such that current through OUT2 is same as the set value. OUT1 will be regulated through S2 working as an LDO linear regulator. • Case B. If the voltage across the FB pin falls below 95% of the set value, the boost stage will be controlled by OUT1. The current through OUT2 will be controlled through S3 working as current sink. WLED Dimming Control In the A8481, WLED brightness can be controlled by the follwing variety of methods: • External resistance on the ISET pin Dimming level can be set by controlling the resistance between the ISET pin and ground. The resistance between the ISET pin and ground can be dynamically controlled by switching a parallel resistor, RP , as shown in figure 1b. • Serial programming through the ON2 pin The OUT2 pin current can be adjusted by clocking the ON2 pin to 8 different levels, ranging from 8% to 100% of the level determined by RSET. An internal digital circuit decodes the clock signal and sets the current of the OUT2 pin. Figure 2 illustrates the timing definition of the clock at the ON2 pin. The 8 levels of serial dimming are shown in the following table. Pulse Count 0 1 2 3 IOUT2 100% 87% 74% 61% Pulse Count 4 5 6 7 8 IOUT2 47% 34% 21% 8% 100% The OUT2 pin provides a constant-current sink for a set of series-connected WLEDs. It is capable of sinking 20 mA current. Switch S3 is the current regulator. Current through S3 can be adjusted by controlling resistor connected to the ISET pin. It can also be programmed through the ON2 pin. The IC provides protections against output overvoltage on the CAP pin, overload, and over temperature. Also, it has an input undervoltage lockout to avoid malfunction and battery drain. At light loads, instantaneous inductor current drops to zero. This is known as discontinuous mode operation and will result in some low frequency ripple. In discontinuous mode, the voltage at the SW pin will ring, due to the resonant LC circuit formed by the inductor and the switch and diode capacitance. This ringing is low frequency and is not harmful. It can be damped with a resistor across the inductor, but this will reduce efficiency and is not recommended. Start-up Sequence When either or both outputs, OUT1 and OUT2, are enabled and VIN is greater than VIN (min), the boost stage is ramped-up with soft start. If only OUT1 is enabled, it controls the boost stage soft start. OUT2 controls soft start if only OUT2 is enabled. When only one output is enabled, the corresponding output switch, S2 or S3, completely turns on. If ON1 and ON2 are both enabled at start-up, the boost stage is controlled by the channel that requires greater voltage than the other channel. Both outputs turn on simultaneously. When both enable signals are low, the A8481 enters shutdown mode. The default setting is 100% , which is the OUT2 level when no clock pulse has been applied. The OUT2 current level is decreased in steps as each pulse is applied. After the minimum level is reached, the counter rolls over to 100% again. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 A8481 Dual Output Boost Regulator Using Single Inductor Dimming with serial programming is disabled during startup, for the initialization period, tHII . When ON2 is pulled low for time longer than tSHDN, the counter resets. When changing from one specific dimming level to another, the user may not want to have to store the latest dimming level. A simpler method is to program a memory reset and apply the required number of pulses, from 100% to the target dimming level. The total “LED off” time during shutdown, reenable, and dimming level programming can be kept sufficiently short, such that no delay is discernable to the human eye. • PWM Control through the ON2 pin The average current for the LEDs can be determined by controlling the duty cycle of the LED current using external PWM on ON2 pin. When the ON2 pin is high, current at the 100% level flows through the LEDs. When ON2 is low, the LED current is less than 1 μA. PWM can be applied only after the tHII period. The duty cycle and frequency range will be limited due to tSHDN. Typically, PWM control through the range of 0 to 80% can be achieved at 100 Hz PWM frequency. • PWM Control through the ISET pin The average current for the LEDs can be controlled with external PWM on the ISET pin, as shown in figure 4a. PWM dimming accuracy is shown in figure 3. The PWM source used had a high level of 3 V and low level of 0 V. Also, RSET =30 kΩ and RP =100 Ω. LED Supply Current versus Duty Cycle PWM control via ISET pin 25 20 fPWM (Hz) 200 400 1000 ILED (mA) 15 10 5 0 0 20 40 DC (%) 60 80 100 Figure 3. Accuracy of External PWM on ISET Initial tHII 0 VON2 tSS 100% 1 2 3 4 5 6 7 0 1 2 tLO 87% 74% 61% 47% 34% tHI 100% 21% 8% 87% 74% tSHDN Memory Reset IOUT2 SHDN Figure 2. ON2 Clock Timing Definition Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 A8481 Dual Output Boost Regulator Using Single Inductor Applications Information Component Selection The component values shown in the application circuits (figures 1 and 4) will be sufficient for most applications. To reduce the output ripple, the output inductor may be increased in value, but in most cases this will result in excessive board area and cost. Inductor Selection The inductor is the most important component in the power supply design because it affects the steady-state performance, transient response, and loop stability. The inductance value, dc resistance, and the saturation current should be considered when choosing the inductor. The dc current of the inductor can be calculated by: VOUT IOUT VIN η and the inductance value can be calculated by: IL_DC = Lmin = Vimin ∆i η (2) rent rating above the circuit maximum. The diode RMS current rating should be: ⎯⎯ IDIODE(RMS) = IOUT = IIN √ 1–D . (4) Diode PIV should be higher than the output voltage on the CAP pin. Capacitor Selection The input capacitor selection is based on the input voltage ripple. It can be calculated as: CIN(min) = 8 f ∆i VIN(ripple) (5) where VIN(ripple) is the input ripple. The output capacitor selection is based on the output ripple requirement. It can be calculated by: COUT = VOUT –VIN VOUT 1 f IOUT (6) ⎛ ⎞ V 1 ⎜1 – imin ⎟ (3) ⎜ VOUT ⎟ f ⎝ ⎠ where ∆i = (20% to 40%) × IL_DC is the peak-to-peak ripple current. Smaller inductance values force the converter into discontinuous mode, which will reduce the maximum output current. Larger inductance values reduce the gain and phase margin, which will result in instability of the loop. The inductor should have low winding resistance, typically < 0.2 Ω and low 1.2 MHz core loss for better efficiency. The inductor should have a saturation current higher than 1.5 A, in order to provide 20 V at the OUTx pins, and 100 mA at 2.7 VIN. For high temperature operation, a suitable derating factor should be considered. Several inductor manufacturers, including: Coilcraft, Murata, Panasonic, Sumida, Taiyo Yuden, and TDK, have and are developing suitable small-size inductors. Diode Selection The diode should have a low forward voltage to reduce conduction losses and a low capacitance to reduce switching losses. Schottky diodes can provide both of these features, if carefully selected. The forward voltage drop is a natural advantage for Schottky diodes and decreases as the current rating increases. However, as the current rating increases, the diode capacitance also increases, so the optimum selection is usually the lowest cur- Vripple(pp) where Vripple is the peak-to-peak output ripple. In addition, the ESR-related output ripple can be calculated by: Vripple(ESR) = IOUT ESR . (7) If a ceramic capacitor is selected, the ESR-related ripple can be neglected, due to the low ESR. If a tantalum electrolytic capacitor is selected, this portion of ripple voltage has to be considered. During load transient response, a larger output capacitance always helps to supply or absorb additional current, which results in lower overshoot and undershoot voltage. Because the capacitor values are low, ceramic capacitors are the best choice for this application. To reduce performance variation over temperature, low drift types such as X7R and X5R should be used. Recommended specifications are shown in the table below. Suitable capacitors are available from TDK, Taiyo Yuden, Murata, Kemet, and AVX. The output capacitor is placed on the CAP pin only. An additional capacitor can be added on the OUT1 pin, but it is not needed for proper operation and it cannot replace the capacitor on the CAP pin. Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 10 A8481 Dual Output Boost Regulator Using Single Inductor VOUT L1 1 CIN VSUPPLY 2 3 4 5 GND FB1 VIN SW CAP 10 9 8 7 6 R1 OLED VSUPPLY D1 COUT CIN 1 2 3 4 5 GND FB1 VIN L1 SW CAP 10 9 8 7 D1 VOUT COUT A8481 OUT1 ISET ON1 A8481 OUT1 ISET ON1 OUT2 ON2 OUT2 ON2 RP PWM RSET R2 RSET R2 Figure 4a. OUT2 current dimming with PWM on ISET pin VOUT L1 10 μH 1 2 Li+ Battery 2.7 to 5.5 V CIN 1 μF 16 V 3 4 5 GND FB1 VIN L2 10 μH SW CAP 10 9 8 7 6 D9 D10 D0 D1 D2 Figure 4b. Three WLED and OLED driver Efficiency versus Input Voltage 77 76 75 74 A8481 η (%) OUT1 ISET ON1 OUT2 ON2 COUT 1 μF 50 V 73 72 71 70 69 68 2.5 3.0 3.5 4.0 4.5 5.0 5.5 R1 30 kΩ VIN (V) Figure 4c. Ten WLED driver VOUT L1 1 CIN VSUPPLY 2 3 4 5 GND FB1 VIN SW CAP 10 9 8 7 6 D5 D6 D7 Flash D0 D1 D2 D3 D4 COUT VSUPPLY Backlight CIN 1 2 3 4 5 GND FB1 VIN L1 SW CAP 10 D0 D1 VOUT Main 9 8 7 6 Dz Dy Sub Dx COUT A8481 OUT1 ISET ON1 A8481 OUT1 ISET ON1 OUT2 ON2 OUT2 ON2 RSET R2 RSET R2 Figure 4d. Four WLED backlight and three 100 mA WLED flash driver Figure 4e. WLED Main and WLED sub driver Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com OLED 6 R1 11 A8481 Dual Output Boost Regulator Using Single Inductor Package EJ, 10-Pin MLP/DFN 0.30 3.00 10 0.85 0.50 10 3.00 A 1 D 0.08 C 0.25 0.50 2 1 11X 0.75 C PCB Layout Reference View 2.38 1.65 3.10 1 2 0.40 1.65 B All dimensions nominal, not for tooling use (reference JEDEC MO-229WEED) Dimensions in millimeters Exact case and lead configuration at supplier discretion within limits shown A Terminal #1 mark area B Exposed thermal pad (reference only, terminal #1 identifier appearance at supplier discretion) C Reference land pattern layout (reference IPC7351 SON50P300X300X80-11WEED3M); All pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary to meet application process requirements and PCB layout tolerances; when mounting on a multilayer PCB, thermal vias at the exposed thermal pad land can improve thermal dissipation (reference EIA/JEDEC Standard JESD51-5) D Coplanarity includes exposed thermal pad and terminals 10 2.38 Copyright ©2006, 2007, Allegro MicroSystems, Inc. The products described here are manufactured under one or more U.S. patents or U.S. 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. Allegro’s products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system. 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. For the latest version of this document, visit our website: www.allegromicro.com Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12