AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator General Description Features The AAT3238 MicroPower low dropout (LDO) linear regulator is ideally suited for portable applications where very fast transient response, extended battery life, and small size are critical. The AAT3238 has been specifically designed for high-speed turn-on and turn-off performance, fast transient response, good power supply ripple rejection (PSRR), and is reasonably low noise, making it ideal for powering sensitive circuits with fast switching requirements. • • • • • • • • • • • Other features include low quiescent current, typically 70µA, and low dropout voltage, typically less than 400mV at the maximum output current level of 300mA. The device is output short-circuit protected and has a thermal shutdown circuit for additional protection under extreme operating conditions. The AAT3238 also features a low-power shutdown mode for extended battery life. A reference bypass pin has been provided to improve PSRR performance and output noise by connecting a small external capacitor from the AAT3238's reference output to ground. The AAT3238 is available in a Pb-free, space-saving 6-pin SOT23 or 8-pin SC70JW package in factoryprogrammed voltages. • • • • • PowerLinear™ Low Dropout: 400mV at 300mA Guaranteed 300mA Output High Accuracy: ±1.5% 70µA Quiescent Current Fast Line and Load Transient Response High-Speed Device Turn-On and Shutdown High Power Supply Ripple Rejection Low Self Noise Short-Circuit Protection Over-Temperature Protection Uses Low Equivalent Series Resistance (ESR) Ceramic Capacitors Noise Reduction Bypass Capacitor Shutdown Mode for Longer Battery Life Low Temperature Coefficient Factory-Programmed Output Voltages SOT23 6-Pin or SC70JW 8-Pin Package Applications • • • • • Cellular Phones Digital Cameras Notebook Computers Personal Portable Electronics Portable Communication Devices Typical Application VOUT VIN IN OUT AAT3238 ON/OFF BYP EN GND 1μF GND 3238.2006.11.1.6 10nF 2.2μF GND 1 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Pin Descriptions Pin # Symbol Function SOT23-6 SC70JW-8 1 5, 6 IN 2, 5 8 GND 3 7 EN Enable pin; this pin should not be left floating. When pulled low, the PMOS pass transistor turns off and all internal circuitry enters low-power mode, consuming less than 1µA. 4 1 BYP Bypass capacitor connection; to improve AC ripple rejection, connect a 10nF capacitor to GND. This will also provide a softstart function. 6 2, 3, 4 OUT Output pin; should be decoupled with 2.2µF ceramic capacitor. Input voltage pin; should be decoupled with 1µF or greater capacitor. Ground connection pin. Pin Configuration SOT23-6 (Top View) IN 2 1 GND 2 EN 3 SC70JW-8 (Top View) 6 5 4 OUT GND BYP BYP OUT OUT OUT 1 8 2 7 3 6 4 5 GND EN IN IN 3238.2006.11.1.6 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol Description VIN VENIN(MAX) IOUT TJ Input Voltage Maximum EN to Input Voltage DC Output Current Operating Junction Temperature Range Value Units 6 0.3 PD/(VIN - VO) -40 to 150 V V mA °C Recommended Operating Conditions Symbol VIN T Description Input Voltage Ambient Temperature Range2 Rating Units (VOUT + VDO) to 5.5 -40 to +85 V °C Thermal Information3 Symbol ΘJA PD Description Maximum Thermal Resistance Maximum Power Dissipation Rating Units 150 667 °C/W mW 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on a demo board. 3. To calculate minimum input voltage, use the following equation: VIN(MIN) = VOUT(MAX) + VDO(MAX) as long as VIN ≥ 2.5V. 3238.2006.11.1.6 3 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Electrical Characteristics1 VIN = VOUT(NOM) + 1V for VOUT options greater than 1.5V. VIN = 2.5V for VOUT ≤ 1.5V. IOUT = 1mA, COUT = 2.2µF, CIN = 1µF, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C. Symbol VOUT IOUT VDO ISC IQ ISD ΔVOUT/ VOUT*ΔVIN Description Conditions Output Voltage Tolerance IOUT = 1mA to 300mA Output Current Dropout Voltage2, 3 Short-Circuit Current Ground Current Shutdown Current VOUT > 1.2V IOUT = 300mA VOUT < 0.4V VIN = 5V, No Load, EN = VIN VIN = 5V, EN = 0V Line Regulation VIN = VOUT + 1 to 5.0V Dynamic Line Regulation ΔVOUT(load) tENDLY VEN(L) VEN(H) IEN Dynamic Load Regulation Enable Delay Time Enable Threshold Low Enable Threshold High Leakage Current on Enable Pin VEN = 5V TSD THYS eN TC Power Supply Rejection Ratio Over-Temperature Shutdown Threshold Over-Temperature Shutdown Hysteresis Output Noise Output Voltage Temperature Coefficient TA = 25°C TA = -40 to 85°C -1.5 -2.5 300 1kHz IOUT = 10mA, CBYP = 10nF 10kHz 1MHz 1.5 2.5 400 600 70 VIN = VOUT + 1V to VOUT + 2V, IOUT = 300mA, TR/TF = 2µs IOUT = 1mA to 300mA, TR < 5µs BYP = Open ΔVOUT(line) PSRR Min Typ Max Units % 125 1 mA mV mA µA µA 0.09 %/V 600 2.5 mV 60 15 mV µs V V µA 0.6 1.5 1 67 47 45 dB 145 °C 12 °C 50 µVrms 22 ppm/°C 1. The AAT3238 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 2. VDO is defined as VIN - VOUT when VOUT is 98% of nominal. 3. For VOUT < 2.1V, VDO = 2.5V - VOUT. 4 3238.2006.11.1.6 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Dropout Voltage vs. Temperature Dropout Characteristics 3.20 IL = 300mA 480 420 360 300 IL = 100mA IL = 150mA 240 180 120 60 IL = 50mA 0 -40 -30 -20 -10 0 IOUT = 0mA 3.00 Output Voltage (V) Dropout Voltage (mV) 540 2.80 IOUT = 300mA IOUT = 150mA 2.60 2.40 IOUT = 10mA 2.20 2.00 2.70 10 20 30 40 50 60 70 80 90 100 110 120 2.80 Temperature (°C) 2.90 3.10 3.20 3.30 Ground Current vs. Input Voltage 90.00 500 80.00 Ground Current (μA) 450 400 350 300 85°C 250 200 25°C 150 -40°C 100 50 70.00 60.00 0 50 100 150 200 250 IOUT = 300mA 50.00 IOUT = 150mA IOUT = 50mA 40.00 IOUT = 0mA 30.00 IOUT = 10mA 20.00 10.00 0 0.00 300 2 2.5 3 3.5 4 4.5 5 Input Voltage (V) Output Current (mA) Quiescent Current vs. Temperature Output Voltage vs. Temperature 100 1.203 90 1.202 80 Output Voltage (V) Quiescent Current (μA) 3.00 Input Voltage (V) Dropout Voltage vs. Output Current Dropout Voltage (mV) IOUT = 100mA IOUT = 50mA 70 60 50 40 30 20 10 0 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 Temperature (°C) 3238.2006.11.1.6 1.201 1.200 1.199 1.198 1.197 1.196 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 Temperature (°C) 5 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Initial Power-Up Response Time Turn-Off Response Time (CBYP = 10nF) (CBYP = 10nF) VEN (5V/div) VEN (5V/div) VOUT (1V/div) VOUT (1V/div) Time (50µs/div) Time (400µs/div) Line Transient Response Turn-On Time From Enable (VIN present) (CBYP = 10nF) 6 3.04 VEN = 5V/div Input Voltage (V) VIN = 4V VOUT = 1V/div 3.03 VIN 4 3.02 3 3.01 2 3.00 VOUT 1 2.99 0 2.98 Time (5µs/div) Time (100µs/div) 500 2.85 400 2.80 300 2.75 200 2.70 100 2.65 0 IOUT 2.60 -100 Time (100µs/div) 6 3.00 800 2.90 700 2.80 2.70 600 VOUT 500 2.60 400 2.50 300 2.40 2.30 200 100 IOUT 2.20 Output Current (mA) 2.90 Output Voltage (V) Load Transient Response 300mA Output Current (mA) Output Voltage (V) Load Transient Response VOUT Output Voltage (V) 5 0 2.10 -100 Time (10µs/div) 3238.2006.11.1.6 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Over-Current Protection AAT3238 Self Noise 1200 Output Current (mA) Noise Amplitude (μV/rtHz) (COUT = 10μF, Ceramic) 10 1 0.1 0.01 Band Power: 300Hz to 50kHz = 44.6μVrms/rtHz 100Hz to 100kHz = 56.3μVrms/rtHz 1000 800 600 400 200 0 -200 0.001 0.01 0.1 1 10 100 1000 10000 5.0 5.5 Time (20ms/div) Frequency (kHz) VIH and VIL vs. VIN 1.250 1.225 1.200 VIH 1.175 1.150 1.125 VIL 1.100 1.075 1.050 2.5 3.0 3.5 4.0 4.5 VIN (V) 3238.2006.11.1.6 7 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Functional Block Diagram OUT IN Active Feedback Control Over-Current Protection OverTemperature Protection + Error Amplifier - EN Fast Start Control Voltage Reference BYP Functional Description The AAT3238 is intended for LDO regulator applications where output current load requirements range from no load to 300mA. The advanced circuit design of the AAT3238 has been specifically optimized for very fast start-up and shutdown timing. This proprietary CMOS LDO has also been tailored for superior transient response characteristics. These traits are particularly important for applications that require fast power supply timing, such as GSM cellular telephone handsets. The high-speed turn-on capability of the AAT3238 is enabled through the implementation of a fast start control circuit, which accelerates the power-up behavior of fundamental control and feedback circuits within the LDO regulator. Fast turn-off response time is achieved by an active output pull-down circuit, which is enabled when the LDO regulator is placed in the shutdown mode. This active fast shutdown circuit has no adverse effect on normal device operation. The AAT3238 has very fast transient response characteristics, which is an important feature for applications where fast line and load transient response is 8 GND required. This rapid transient response behavior is accomplished through the implementation of an active error amplifier feedback control. This proprietary circuit design is unique to this MicroPower LDO regulator. The LDO regulator output has been specifically optimized to function with low-cost, low-ESR ceramic capacitors. However, the design will allow for operation over a wide range of capacitor types. A bypass pin has been provided to allow the addition of an optional voltage reference bypass capacitor to reduce output self noise and increase power supply ripple rejection. Device self noise and PSRR will be improved by the addition of a small ceramic capacitor in this pin. However, increased values of CBYPASS may slow down the LDO regulator turn-on time. This LDO regulator has complete short-circuit and thermal protection. The integral combination of these two internal protection circuits gives the AAT3238 a comprehensive safety system to guard against extreme adverse operating conditions. Device power dissipation is limited to the package type and thermal dissipation properties. Refer to the Thermal Considerations section of this datasheet for details on device operation at maximum output current loads. 3238.2006.11.1.6 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Applications Information To assure the maximum possible performance is obtained from the AAT3238, please refer to the following application recommendations. Input Capacitor Typically, a 1µF or larger capacitor is recommended for CIN in most applications. A CIN capacitor is not required for basic LDO regulator operation. However, if the AAT3238 is physically located more than three centimeters from an input power source, a CIN capacitor will be needed for stable operation. CIN should be located as closely to the device VIN pin as practically possible. CIN values greater than 1µF will offer superior input line transient response and will assist in maximizing the highest possible power supply ripple rejection. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for CIN. There is no specific capacitor ESR requirement for CIN. However, for 300mA LDO regulator output operation, ceramic capacitors are recommended for CIN due to their inherent capability over tantalum capacitors to withstand input current surges from low impedance sources such as batteries in portable devices. Output Capacitor For proper load voltage regulation and operational stability, a capacitor is required between pins VOUT and GND. The COUT capacitor connection to the LDO regulator ground pin should be made as direct as practically possible for maximum device performance. The AAT3238 has been specifically designed to function with very low ESR ceramic capacitors. For best performance, ceramic capacitors are recommended. Typical output capacitor values for maximum output current conditions range from 1µF to 10µF. Applications utilizing the exceptionally low output noise and optimum power supply ripple rejection characteristics of the AAT3238 should use 2.2µF or greater for COUT. If desired, COUT may be increased without limit. 3238.2006.11.1.6 In low output current applications where output load is less than 10mA, the minimum value for COUT can be as low as 0.47µF. Bypass Capacitor and Low Noise Applications A bypass capacitor pin is provided to enhance the low noise characteristics of the AAT3238 LDO regulator. The bypass capacitor is not necessary for operation of the AAT3238. However, for best device performance, a small ceramic capacitor should be placed between the bypass pin (BYP) and the device ground pin (GND). The value of CBYP may range from 470pF to 10nF. For lowest noise and best possible power supply ripple rejection performance, a 10nF capacitor should be used. To practically realize the highest power supply ripple rejection and lowest output noise performance, it is critical that the capacitor connection between the BYP pin and GND pin be direct and PCB traces should be as short as possible. Refer to the PCB Layout Recommendations section of this document for examples. There is a relationship between the bypass capacitor value and the LDO regulator turn-on and turnoff time. In applications where fast device turn-on and turn-off time are desired, the value of CBYP should be reduced. In applications where low noise performance and/ or ripple rejection are less of a concern, the bypass capacitor may be omitted. The fastest device turnon time will be realized when no bypass capacitor is used. DC leakage on this pin can affect the LDO regulator output noise and voltage regulation performance. For this reason, the use of a low leakage, high quality ceramic (NPO or C0G type) or film capacitor is highly recommended. Capacitor Characteristics Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT3238. Ceramic capacitors offer many advantages over their tantalum and aluminum electrolytic counterparts. A ceramic capacitor typically 9 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator has very low ESR, is lower cost, has a smaller PCB footprint, and is non-polarized. Line and load transient response of the LDO regulator is improved by using low-ESR ceramic capacitors. Since ceramic capacitors are non-polarized, they are not prone to incorrect connection damage. Equivalent Series Resistance: ESR is a very important characteristic to consider when selecting a capacitor. ESR is the internal series resistance associated with a capacitor that includes lead resistance, internal connections, size and area, material composition, and ambient temperature. Typically, capacitor ESR is measured in milliohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors. Ceramic Capacitor Materials: Ceramic capacitors less than 0.1µF are typically made from NPO or C0G materials. NPO and C0G materials generally have tight tolerance and are very stable over temperature. Larger capacitor values are usually composed of X7R, X5R, Z5U, or Y5V dielectric materials. These two material types are not recommended for use with LDO regulators since the capacitor tolerance can vary more than ±50% over the operating temperature range of the device. A 2.2µF Y5V capacitor could be reduced to 1µF over temperature; this could cause problems for circuit operation. X7R and X5R dielectrics are much more desirable. The temperature tolerance of X7R dielectric is better than ±15%. Capacitor area is another contributor to ESR. Capacitors that are physically large in size will have a lower ESR when compared to a smaller sized capacitor of an equivalent material and capacitance value. These larger devices can improve circuit transient response when compared to an equal value capacitor in a smaller package size. Consult capacitor vendor datasheets carefully when selecting capacitors for LDO regulators. 10 Enable Function The AAT3238 features an LDO regulator enable/ disable function. This pin (EN) is active high and is compatible with CMOS logic. To assure the LDO regulator will switch on, the EN turn-on control level must be greater than 1.5V. The LDO regulator will go into the disable shutdown mode when the voltage on the EN pin falls below 0.6V. If the enable function is not needed in a specific application, it may be tied to VIN to keep the LDO regulator in a continuously on state. When the LDO regulator is in shutdown mode, an internal 1.5kΩ resistor is connected between VOUT and GND. This is intended to discharge COUT when the LDO regulator is disabled. The internal 1.5kΩ has no adverse effect on device turn-on time. Short-Circuit Protection The AAT3238 contains an internal short-circuit protection circuit that will trigger when the output load current exceeds the internal threshold limit. Under short-circuit conditions, the output of the LDO regulator will be current limited until the short-circuit condition is removed from the output or the LDO regulator package power dissipation exceeds the device thermal limit. Thermal Protection The AAT3238 has an internal thermal protection circuit which will turn on when the device die temperature exceeds 145°C. The internal thermal protection circuit will actively turn off the LDO regulator output pass device to prevent the possibility of overtemperature damage. The LDO regulator output will remain in a shutdown state until the internal die temperature falls back below the 145°C trip point. The combination and interaction between the shortcircuit and thermal protection systems allow the LDO regulator to withstand indefinite short-circuit conditions without sustaining permanent damage. 3238.2006.11.1.6 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator No-Load Stability The AAT3238 is designed to maintain output voltage regulation and stability under operational noload conditions. This is an important characteristic for applications where the output current may drop to zero. Reverse Output-to-Input Voltage Conditions and Protection Under normal operating conditions, a parasitic diode exists between the output and input of the LDO regulator. The input voltage should always remain greater than the output load voltage, maintaining a reverse bias on the internal parasitic diode. Conditions where VOUT might exceed VIN 3238.2006.11.1.6 should be avoided since this would forward bias the internal parasitic diode and allow excessive current flow into the VOUT pin, possibly damaging the LDO regulator. In applications where there is a possibility of VOUT exceeding VIN for brief amounts of time during normal operation, the use of a larger value CIN capacitor is highly recommended. A larger value of CIN with respect to COUT will effect a slower CIN decay rate during shutdown, thus preventing VOUT from exceeding VIN. In applications where there is a greater danger of VOUT exceeding VIN for extended periods of time, it is recommended to place a Schottky diode across VIN to VOUT (connecting the cathode to VIN and anode to VOUT). The Schottky diode forward voltage should be less than 0.45V. 11 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Ordering Information Output Voltage Package Marking1 Part Number (Tape and Reel)2 1.2V 1.5V 1.6V 1.8V 1.85V 2.0V 2.3V 2.5V 2.7V 2.8V 2.85 3.0V 3.3V 3.5V 1.2V 1.45V 1.5V 1.8V 2.0V 2.3V 2.5V 2.7V 2.8V 2.85 3.0V 3.3V 3.5V SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 KIXYY JGXYY JSXYY JRXYY JFXYY AAT3238IGU-1.2-T1 AAT3238IGU-1.5-T1 AAT3238IGU-1.6-T1 AAT3238IGU-1.8-T1 AAT3238IGU-1.85-T1 AAT3238IGU-2.0-T1 AAT3238IGU-2.3-T1 AAT3238IGU-2.5-T1 AAT3238IGU-2.7-T1 AAT3238IGU-2.8-T1 AAT3238IGU-2.85-T1 AAT3238IGU-3.0-T1 AAT3238IGU-3.3-T1 AAT3238IGU-3.5-T1 AAT3238IJS-1.2-T1 AAT3238IJS-1.45-T1 AAT3238IJS-1.5-T1 AAT3238IJS-1.8-T1 AAT3238IJS-2.0-T1 AAT3238IJS-2.3-T1 AAT3238IJS-2.5-T1 AAT3238IJS-2.7-T1 AAT3238IJS-2.8-T1 AAT3238IJS-2.85-T1 AAT3238IJS-3.0-T1 AAT3238IJS-3.3-T1 AAT3238IJS-3.5-T1 KUXYY QGXYY JGXYY FCXYY VOXYY All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 12 3238.2006.11.1.6 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator Package Information SOT23-6 2.85 ± 0.15 1.90 BSC 2.80 ± 0.20 0.15 ± 0.07 4° ± 4° 1.10 ± 0.20 1.20 ± 0.25 0.075 ± 0.075 1.575 ± 0.125 0.95 BSC 10° ± 5° 0.40 ± 0.10 × 6 0.60 REF 0.45 ± 0.15 GAUGE PLANE 0.10 BSC SC70JW-8 2.20 ± 0.20 1.75 ± 0.10 0.50 BSC 0.50 BSC 0.50 BSC 0.225 ± 0.075 2.00 ± 0.20 0.100 7° ± 3° 0.45 ± 0.10 4° ± 4° 0.05 ± 0.05 0.15 ± 0.05 1.10 MAX 0.85 ± 0.15 0.048REF 2.10 ± 0.30 All dimensions in millimeters. 3238.2006.11.1.6 13 AAT3238 300mA MicroPower™ High Performance LDO Linear Regulator © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 14 3238.2006.11.1.6