A4481 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection FEATURES AND BENEFITS • • • • • Automotive AEC-Q100 qualified 5.25 to 40 VIN operating range, 50 V load dump rating 5 V ±1% internal LDO regulator Foldback short-circuit protection Short-to-battery protection (to 32 V, independent of VIN) for harness faults • Power OK (POK) flag • High-voltage logic level enable input (ENB) for microprocessor control or connection directly to battery • Pin-to-pin and pin-to-ground tolerant at every pin Package: 8-pin SOIC with exposed thermal pad (suffix LJ) DESCRIPTION The A4481 is a single low-dropout linear regulator with complete control, diagnostics, and protection features that address many requirements of automotive applications. It regulates input voltages from 5.25 to 40 V, down to 5 V ±1% output voltage and is able to supply up to 50 mA of load current. Diagnostic output from the A4481 includes Power OK (POK) output to alert the microprocessor that a fault has occurred. Protection features include input undervoltage lockout (UVLO), foldback overcurrent protection, output undervoltage and overvoltage protections (UV/OVP), and thermal shutdown (TSD). In addition, the output is protected from a short-tobattery event up to 32 V. The A4481 device is available in an 8-pin SOIC package with exposed pad for enhanced thermal dissipation. It is lead (Pb) free, with 100% matte-tin leadframe plating. APPLICATIONS Power supplies for: • Microcontrollers • Transceivers (CAN, LIN, etc.) • Sensors Not to scale Typical Application Circuit VIN VIN VOUT A4481 Enable A4481-DS POK ENB GND VOUT = 5 V, IOUT = 50 mA VCC 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 SELECTION GUIDE Part Number Temperature Range (ºC) Package Packing* A4481KLJTR-T –40 to 150 8-pin eSOIC with exposed thermal pad 3000 pieces per 7-in. reel *Contact Allegro for additional packing options. ABSOLUTE MAXIMUM RATINGS* Characteristic Symbol VIN, ENB Pins Notes VIN, VENB VOUT Pin VOUT Independent of VIN All other pins Rating Unit –0.3 to 50 V –0.3 to 32 V –0.3 to 7 V Junction Temperature Range TJ(max) –40 to 165 °C Storage Temperature Range Tstg –40 to 150 °C *Stresses beyond those listed in this table may cause permanent damage to the device. The absolute maximum ratings are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the Electrical Characteristics table is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability THERMAL CHARACTERISTICS:* May require derating at maximum conditions; see application section for optimization Characteristic Package Thermal Resistance (Junction to Ambient) Symbol RθJA Test Conditions* eSOIC-8 (LJ) package Value Unit 35 ºC/W *Additional thermal information available on the Allegro website. Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 Functional Block Diagram Foldback Short to VBAT Protection 5V LDO VIN LDO VOUT VCC ENB POK VOUT UV/OV OCP TSD Pin-Out Diagram GND Terminal List Table Number Name Function VIN 1 8 VOUT 1 VIN Input voltage pin VIN 2 7 GND 2 VIN Input voltage pin 3 NC No connect 4 ENB Logic enable input from a microcontroller or DSP 5 POK Open-drain regulator fault detection output 6 GND Ground 7 GND Ground 8 VOUT 5 V regulator output NC 3 ENB 4 PAD 6 GND 5 POK Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 ELECTRICAL CHARACTERISTICS1: Valid at 5.25 V ≤ VINx ≤ 40 V, −40ºC ≤ TA = TJ ≤ 150ºC, unless otherwise specified Characteristics Symbol Test Conditions Min. Typ. Max. Units ENB high 5.25 5.35 40 V Input Voltage Operating Input Voltage VIN VIN UVLO Start Voltage VIN(START) VIN rising, ENB high 4.75 – 5.2 V VIN UVLO Stop Voltage VIN(STOP) VIN falling, ENB high 4.55 – 5 V VIN UVLO Hysteresis VIN(HYS) VIN(START) – VIN(STOP) – 0.2 – V IQ VIN = 5.25 V, ENB high – 3.4 – mA IQ(SLEEP) VIN = 5.25 V, ENB low – 1 10 µA 4.95 5 5.05 V –1 – +1 % 3 4.7 10 µF 0.7 1.5 2.3 ms Input Current Input Quiescent Current1 Input Sleep Supply Current1 5 V Linear Regulator Accuracy VOUT Load Regulation IOUT = 25 mA, VIN = 5.25 V 5 mA < IOUT < 50 mA, VIN = 5.25 V Output Capacitance Range2 COUT Startup Time2 tSTART COUT ≤ 4.7 µF, Load = 100 Ω ±5% (50 mA) VENB(H) VENB rising – – 2 V VENB(L) VENB falling 0.8 – – V RENB – 100 – kΩ td(EN,FILT) 10 15 25 µs Login Enable (ENB) Input ENB Threshold ENB Resistance ENB Filter/Deglitch Time Overcurrent Protection (OCP) Current Limit1 ILIM VOUT = 5 V −55 −80 −140 mA IFBK VOUT = 0 V −3 −15 −27 mA Thermal Shutdown Threshold2 TTSD TJ rising 165 − − ºC Hysteresis2 THYS − 15 − ºC Foldback Current1 Thermal Protection (TSD) Thermal Shutdown VOUT OV/UV Protections VOUT OV Thresholds VOUT OV Hysteresis VOUT UV Thresholds VOUT UV Hysteresis VOUT Output Disconnect Threshold VOV(H) VOUT rising 5.15 5.33 5.5 V VOV(L) VOUT falling – 5.3 – V VOV(HYS) VOV(H) – VOV(L) 15 30 50 mV VUV(H) VOUT rising – 4.71 – V VUV(L) VOUT falling 4.5 4.68 4.85 V VUV(H) – VUV(L) 15 30 50 mV VOUT rising – 7.2 – V ENB high, VIN ≥ 5.25 V, IPOK = 4 mA – 150 400 mV VUV(HYS) VDISC POK Outputs POK Output Low Voltage POK Leakage Current1 OV and UV Filter/Deglitch Times2 VPOK(L) IPOK(LKG) td(FILT) VPOK = 3.3 V – – 2 µA Applies to undervoltage of the VOUT voltages 10 15 20 µs For input and output current specifications, negative current is defined as coming out of the node or pin (sourcing), positive current is defined as going into the node or pin (sinking). 2 Ensured by design and characterization, not production tested. 1 Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 4 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 5.05 5.04 5.03 5.02 5.01 5 4.99 4.98 4.97 4.96 4.95 Input/Output Differential (mV) Output Voltage (V) TYPICAL PERFORMANCE CHARACTERISTICS -50 -25 0 25 50 75 Temperature (°C) 100 125 160 140 120 100 80 60 40 20 0 0 150 6.00 80 5.00 70 3.00 2.00 50 50 40 30 20 1.00 10 0 0 10 20 30 40 50 60 Output Current (mA) 70 80 90 102 300 400 500 600 Time (µs) 700 105 106 107 800 900 1000 Load Transient Response (VIN = 12 V, IOUT = 5 mA to 50 mA, COUT = 4.7 µF) VOUT (20 mV/div) 5V VIN (20 V/div) VOUT (20 mV/div) IOUT (20 mA/div) 0A 200 104 Ripple Rejection 5V 100 103 Frequency (Hz) Foldback Current Limit 0 40 60 4.00 0.00 20 30 Output Current (mA) Dropout Voltage vs. Output Current PSRR (dB) Output Voltage (V) Output Voltage vs. Temperature 10 0 0V 100 200 300 400 500 600 700 800 900 1000 Time (ms) Load Dump Characteristics (VIN = 12 to 50 V, IOUT = 50 mA, COUT = 4.7 µF) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 5 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 FUNCTIONAL DESCRIPTION Enable (ENB) Input Power OK (POK) Output The A4481 has an enable (ENB) logic level input pin. To get the A4481 to operate, the ENB pin must be a logic high (>2 V). The ENB pin is rated to 50 V, allowing the ENB pin to be connected directly to VIN if there is no suitable logic signal available to wake up the A4481. When ENB transitions low, the A4481 waits approximately 15 µs before shutting down. This delay provides plenty of filtering to prevent the A4481 from prematurely shutting down because of any small glitch coupling onto the PCB trace or ENB pin. The Power OK (POK) output is an open-drain output, so an external pull-up resistor must be connected. An internal comparator monitors the voltage at the VOUT pin and controls the opendrain device at the POK pin. POK remains low until the voltage at the VOUT pin is within 10% of the final regulation voltage. The POK output is pulled low if: (1) the ENB pin transitions low, (2) UVLO occurs, (3) TSD occurs, or (4) UV/OVP occurs. VIN The following timing diagram shows the basic operation and fault handling of the A4481: VIN(START) VIN(STOP) VENB(H) ENB td(EN,FILT) VENB(L) VDISC VOV(H) VUV(H) VOV(L) VUV(L) VOUT POK POK undefined in this region POK undefined in this region td(FILT) td(FILT) VOUT UV/ Overload at Output td(FILT) td(FILT) Enable glitch POK undefined in this region UVLO Stop UVLO Start td(FILT) td(FILT) VOUT OV Figure 1: Timing Diagram (not to scale) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 6 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 APPLICATION INFORMATION Capacitor Selection Output Capacitor (COUT): The A4481 is designed to be stable with all types of output capacitors, but it must meet the minimum and maximum capacitance requirement of 3 μF and 10 μF at the intended operating temperature and working voltage. For a ceramic capacitor, X5R or X7R dielectrics with 10 V or higher voltage rating are recommended. However, if the part needs to survive short-to-battery events (e.g. to supply off-board sensors), then 50 to 100 V voltage-rated capacitors are recommended. Input Capacitor (CIN): A 2.2 μF or larger capacitor is recommended for an input bypass capacitor. Similarly, choose a capacitor that offers plenty of safety margins for known input voltage applications. rent cannot be ensured for all combinations of ambient temperature and input voltage. The maximum allowable power dissipation in the IC is as follows: PMAX = (TJ(MAX ) − TA ) R θ JA where TJ(MAX) = maximum junction temperature, TA = ambient air temperature, and RθJA thermal = resistance from junction to ambient. (35°C/W for the 8-pin eSOIC). The power dissipated by the IC can be calculated according to the following equation: PDISS = (VIN – VOUT) × IOUT + VIN × IQ Thermal Considerations where VIN = input voltage, VOUT = output voltage, IOUT = output current, and IQ = input quiescent current (3.4 mA typical). The A4481 remains fully operational to 40 V. However, owing to power dissipation characteristics of the package, full output cur- Figure 2 shows current de-rating plot at selected input voltages based on the above calculations. 60 Output Current – mA 50 40 30 20 10 0 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 Ambient Temperature – °C VIN = 5.35 V VIN = 10 V VIN = 14 V VIN = 20 V VIN = 32 V VIN = 40 V Figure 2: Output Current De-Rating vs. Input Voltage Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 7 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 PCB LAYOUT GUIDELINES Place the input and output capacitors as close as possible and on the same side of the PCB and IC. Place thermal vias directly under the device in a tight pattern, as shown in Figure 4, to improve dissipation. Ground Input Capacitor VIN Tie directly to VIN to automatically enable the A4481 µP Enable Output Capacitor VIN 1 8 VOUT VIN 2 7 GND VOUT PAD NC 3 6 GND ENB 4 5 POK PowerOK Output Figure 3: A4481 Layout Example Signal traces LJ package footprint 0.7 mm 0.7 mm LJ package exposed thermal pad Top-layer exposed copper Ø0.3 mm via Figure 4: Suggested PCB layout for thermal optimization (maximum available bottom-layer copper recommended) Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 8 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection A4481 PACKAGE OUTLINE DRAWING 4.90 ±0.10 0.65 8° 0° 8 B A 1 3.90 ±0.10 6.00 ±0.20 0.25 BSC SEATING PLANE GAUGE PLANE Branded Face SEATING PLANE 0.10 C 1.27 BSC 1 1.27 0.40 3.30 NOM 0.51 0.31 2.41 1.04 REF 2 8X C 5.60 2 3.30 C PCB Layout Reference View For Reference Only; not for tooling use (reference MS-012BA) Dimensions in millimeters Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown 1.70 MAX 0.15 0.00 1.27 1.75 0.25 0.17 2.41 NOM 8 A Terminal #1 mark area B Exposed thermal pad (bottom surface); dimensions may vary with device C Reference land pattern layout (reference IPC7351 SOIC127P600X175-9AM); 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) Figure 5: Package LJ, 8-Pin eSOIC Allegro MicroSystems, LLC 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 9 A4481 5 VOUT, 50 mA Automotive Linear Regulator with 50 V Load Dump and Short-to-Battery Protection Revision History Revision Revision Date – October 9, 2015 Description of Revision Initial Release 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. 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 10