AAT3237 300mA MicroPower™ LDO with PowerOK General Description Features The AAT3237 MicroPower low dropout (LDO) linear regulator is ideally suited for portable applications where low noise, extended battery life, and small size are critical. The AAT3237 has been specifically designed for low output noise performance, fast transient response, and high power supply rejection ratio (PSRR). • • • • • • • • • • Other features include low quiescent current, typically 70µA, and low dropout voltage, typically less than 400mV at full output current. The device is output short-circuit protected and has a thermal shutdown circuit for additional protection under extreme conditions. The AAT3237 also features a low-power shutdown mode for extended battery life. A Power-OK opendrain output signals when VOUT is in regulation. The AAT3237 is available in a Pb-free, space-saving 6-pin SOT23 or 8-pin SC70JW package in 13 factory-programmed voltages: 1.2V, 1.5V, 1.8V, 2.0V, 2.3V, 2.5V, 2.7V, 2.8V, 2.85V, 2.9V, 3.0V, 3.3V, or 3.5V. • • • • PowerLinear™™ SmartSwitch Low Dropout: 400mV at 300mA Guaranteed 300mA Output High Accuracy ±1.5% 70µA Quiescent Current High Power Supply Ripple Rejection Power-OK (POK) Output Fast Line and Load Transient Response Short-Circuit Protection Over-Temperature Protection Uses Low Equivalent Series Resistance (ESR) Ceramic Capacitors Shutdown Mode for Longer Battery Life Low Temperature Coefficient 13 Factory-Programmed Output Voltages SOT23 6-Pin or SC70JW 8-Pin Package Applications • • • • • • Cellular Phones Desktop Computers Digital Cameras Notebook Computers Personal Portable Electronics Portable Communication Devices Typical Application VIN VOUT IN OUT AAT3237 ON/OFF POK EN POK GND 1µF GND 3237.2006.01.1.4 2.2µF GND 1 AAT3237 300mA MicroPower™ LDO with PowerOK 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 POK Power-OK output. This open-drain output is low when OUT is out of regulation. Connect a pull-up resistor from POK to OUT. 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 GND EN 2 1 2 3 SC70JW-8 (Top View) 6 5 4 OUT GND POK POK OUT OUT OUT 1 8 2 7 3 6 4 5 GND EN IN IN 3237.2006.01.1.4 AAT3237 300mA MicroPower™ LDO with PowerOK Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol Description VIN, POK VENIN(MAX) IOUT TJ TLEAD Input Voltage, POK Maximum EN to Input Voltage DC Output Current Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units 6 0.3 PD/(VIN - VO) -40 to 150 300 V V mA °C °C Rating Units 150 667 °C/W mW Thermal Information2 Symbol ΘJA PD Description Maximum Thermal Resistance (SOT23-6, SC70JW-8) Maximum Power Dissipation (SOT23-6, SC70JW-8) Recommended Operating Conditions Symbol VIN T Description Input Voltage3 Ambient Temperature Range Rating Units (VOUT + VDO) to 5.5 -40 to +85 V °C 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. 3237.2006.01.1.4 3 AAT3237 300mA MicroPower™ LDO with PowerOK Electrical Characteristics 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 ∆VOUT/ VOUT*∆VIN Description Conditions Output Voltage Tolerance IOUT = 1mA to 300mA Output Current Dropout Voltage 1, 2 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 3 VIN = VOUT + 1 to 5.0V ∆VOUT(line) Dynamic Line Regulation ∆VOUT(load) VEN(L) VEN(H) IEN VPOK VPOKHYS VPOK(OL) IPOK Dynamic Load Regulation Enable Threshold Low Enable Threshold High Leakage Current on Enable Pin POK Trip Threshold POK Hysteresis POK Output Voltage Low POK Output Leakage Current PSRR TSD THYS eN TC Power Supply Rejection Ratio Min Typ Max TA = 25°C TA = -40 to 85°C -1.5 -2.5 300 1.5 2.5 400 600 70 VIN = VOUT + 1V to VOUT + 2V, IOUT = 300mA, TR/TF = 2µs IOUT = 1mA to 300mA, TR <5µs 125 1 0.09 %/V 5 mV 60 1.5 ISINK = 1mA VPOK < 5.5V, VOUT in Regulation 1kHz IOUT = 10mA 10kHz 1MHz Over-Temperature Shutdown Threshold Over-Temperature Shutdown Hysteresis Output Noise Output Voltage Temperature Coefficient 90 94 1 % mA mV mA µA µA 600 0.6 VEN = 5V VOUT Rising, TA = 25°C Units 1 98 0.4 1 mV V V µA % of VOUT % of VOUT V µA 65 45 42 dB 145 °C 12 °C 250 µVrms 22 ppm/°C 1. VDO is defined as VIN - VOUT when VOUT is 98% of nominal. 2. For VOUT < 2.1V, VDO = 2.5V - VOUT. 3. CIN = 10µF. 4 3237.2006.01.1.4 AAT3237 300mA MicroPower™ LDO with PowerOK Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Dropout Characteristics Dropout Voltage vs. Temperature 3.20 Output Voltage (V) Dropout Voltage (mV) 540 IL = 300mA 480 420 360 300 IL = 100mA IL = 150mA 240 180 120 IOUT = 0mA 3.00 2.80 IOUT = 300mA IOUT = 150mA 2.60 2.40 2.20 60 IL = 50mA 0 -40 -30 -20 -10 0 IOUT = 10mA 2.00 2.70 10 20 30 40 50 60 70 80 90 100 110 120 2.80 IOUT = 100mA IOUT = 50mA 2.90 3.00 3.10 3.20 3.30 Input Voltage (V) Temperature (°C) Ground Current vs. Input Voltage Dropout Voltage vs. Output Current 90.00 500 80.00 Ground Current (µA) Dropout Voltage (mV) 450 400 350 300 85°C 250 200 25°C 150 -40°C 100 50 70.00 60.00 IOUT = 300mA 50.00 IOUT = 150mA IOUT = 50mA 40.00 IOUT = 0mA 30.00 IOUT = 10mA 20.00 10.00 0 0.00 0 50 100 150 200 250 300 2 2.5 3 4 4.5 5 Output Voltage vs. Temperature Quiescent Current vs. Temperature 1.203 100 90 1.202 80 Output Voltage (V) Quiescent Current (µA) 3.5 Input Voltage (V) Output Current (mA) 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) 3237.2006.01.1.4 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 AAT3237 300mA MicroPower™ LDO with PowerOK Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Turn-Off Time with POK Delay Turn-On Time and POK Delay VENABLE (2V/div) VEN (2V/div) VOUT (500mV/div) VPOK (2V/div) VPOK (500mV/div) VOUT (2V/div) Time (200µs/div) Time (10µs/div) Line Transient Response POK Output Response VIN (2V/div) 6 VIN 3.20 4 3.15 3 3.10 2 3.05 1 0 3.00 VOUT 2.95 -1 Output Voltage (V) Input Voltage (V) 5 3.25 VOUT (2V/div) VPOK (1V/div) 2.90 -2 2.85 Time (200µs/div) Time (100µs/div) Load Transient Response 300mA Load Transient Response 2.80 300 2.75 200 2.70 2.65 100 IOUT 0 Output Voltage (V) 400 VOUT 3.00 800 2.90 700 2.80 600 VOUT 2.70 500 2.60 400 2.50 300 2.40 200 2.30 100 IOUT 2.20 2.60 -100 Time (100µs/div) 6 Output Current (mA) 2.85 500 Output Current (mA) Output Voltage (V) 2.90 0 2.10 -100 Time (10µs/div) 3237.2006.01.1.4 AAT3237 300mA MicroPower™ LDO with PowerOK Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Over-Current Protection AAT3237 Self Noise Noise Amplitude (µV/rtHz) Output Current (mA) 1200 1000 800 600 400 200 0 10 1 0.1 0.01 0.01 -200 Time (20ms/div) 0.1 1 10 100 1000 Frequency (kHz) VEN(H) and V EN(L) vs. VIN 1.250 1.225 VEN (V) 1.200 1.175 VEN(H) 1.150 1.125 VEN(L) 1.100 1.075 1.050 2.5 3.0 3.5 4.0 4.5 5.0 5.5 VIN (V) 3237.2006.01.1.4 7 AAT3237 300mA MicroPower™ LDO with PowerOK Functional Block Diagram IN OUT Over-Current Protection Over-Temperature Protection Error Amplifier EN POK Voltage Reference 94% GND Functional Description The AAT3237 is intended for LDO regulator applications where output current load requirements range from no load to 300mA. The advanced circuit design of the AAT3237 provides excellent transient response and fast turn-on ability. 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. The AAT3237 has an integrated Power-OK comparator which indicates when the output is out of regulation. 8 The device enable circuit is provided to shut down the LDO regulator for power conservation in portable products. The enable circuit has an additional output capacitor discharge circuit to assure sharp application circuit turn-off upon device shutdown. This LDO regulator has complete short-circuit and thermal protection. The integral combination of these two internal protection circuits gives the AAT3237 a comprehensive safety system during 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. 3237.2006.01.1.4 AAT3237 300mA MicroPower™ LDO with PowerOK Applications Information To assure the maximum possible performance is obtained from the AAT3237, 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 AAT3237 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 AAT3237 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 AAT3237 should use 2.2µF or greater for COUT. If desired, COUT may be increased without limit. Capacitor Characteristics Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT3237. Ceramic capacitors offer many advantages over their tantalum and aluminum electrolytic counterparts. A ceramic capacitor typically 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. In low output current applications where output load is less than 10mA, the minimum value for COUT can be as low as 0.47µF. 3237.2006.01.1.4 9 AAT3237 300mA MicroPower™ LDO with PowerOK POK Output The AAT3237 features an integrated Power-OK comparator which can be used as an error flag. The POK open-drain output goes low when OUT is 6% below its nominal regulation voltage. Connect a pull-up resistor from POK to OUT. Enable Function The AAT3237 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 2.0V. 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 AAT3237 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 LDO regulator package power dissipation exceeds the device thermal limit. Thermal Protection The AAT3237 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 10 pass device to prevent the possibility of over-temperature 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 allows the LDO regulator to withstand indefinite short-circuit conditions without sustaining permanent damage. No-Load Stability The AAT3237 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 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. 3237.2006.01.1.4 AAT3237 300mA MicroPower™ LDO with PowerOK Ordering Information Output Voltage Package 1.2V 1.5V 1.8V 2.0V 2.3V 2.5V 2.7V 2.8V 2.85V 2.9V 3.0V 3.3V 3.5V 1.2V 1.5V 1.8V 2.0V 2.3V 2.5V 2.7V 2.8V 2.85V 2.9V 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 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 Marking1 FBXYY GRXYY GSXYY GMXYY HRXYY Part Number (Tape and Reel)2 AAT3237IGU-1.2-T1 AAT3237IGU-1.5-T1 AAT3237IGU-1.8-T1 AAT3237IGU-2.0-T1 AAT3237IGU-2.3-T1 AAT3237IGU-2.5-T1 AAT3237IGU-2.7-T1 AAT3237IGU-2.8-T1 AAT3237IGU-2.85-T1 AAT3237IGU-2.9-T1 AAT3237IGU-3.0-T1 AAT3237IGU-3.3-T1 AAT3237IGU-3.5-T1 AAT3237IJS-1.2-T1 AAT3237IJS-1.5-T1 AAT3237IJS-1.8-T1 AAT3237IJS-2.0-T1 AAT3237IJS-2.3-T1 AAT3237IJS-2.5-T1 AAT3237IJS-2.7-T1 AAT3237IJS-2.8-T1 AAT3237IJS-2.85-T1 AAT3237IJS-2.9-T1 AAT3237IJS-3.0-T1 AAT3237IJS-3.3-T1 AAT3237IJS-3.5-T1 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 all part numbers listed in BOLD. 3237.2006.01.1.4 11 AAT3237 300mA MicroPower™ LDO with PowerOK Package Information SOT23-6 2.85 ± 0.15 1.90 BSC 2.80 ± 0.20 1.20 ± 0.25 0.15 ± 0.07 4° ± 4° 1.10 ± 0.20 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 All dimensions in millimeters. 12 3237.2006.01.1.4 AAT3237 300mA MicroPower™ LDO with PowerOK 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. © 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 3237.2006.01.1.4 13