AQ1541

AQ1541 Low Dropout 1 Amp Voltage Regulator with Enable Function Product Specification Revision 2.2 September 13, 2006 General Description The AQ1541 is a low dropout three terminal voltage regulator, offered in popular fixed options or an adjustable version that can set a precise voltage from 1.22V to 12V with two external resistors. It drops into the footprint of the popular LM1117 SOT-223 and provides a true fourth pin separated from the output tab. The extra pin allows for an enable function that provides a remote turn-off for low power consumption. It draws virtually zero current in shutdown mode. The Enable pin implements Sequential, Ratiometric, or Simultaneous sequencing schemes. To assure accuracy within 1.5% over temperature the heart of the AQ1541 is a selfcorrecting AcuRef™ bandgap reference. On-chip current limit and thermal shutdown with hysteresis protects against any combination of overload and ambient temperature that might cause the junction temperature to exceed safe limits. The AQ1541 is featured in the new SOT223 4-lead TetraPackTM package. Applications • Graphic cards • PC motherboards • Switching power supply post-regulation • Telecom equipment • DVD video player Features • Enable pin implements sequencing in • • • • • • • • SOT223-3 footprint Vout tolerance 1.5% over temperature Eliminates expensive components Stable with low cost 1uF capacitor Low dropout voltage (1V at 1 Amp) Thermal protection with hysteresis Short circuit protection Offered with 1.8V, 2.5V, and 3.3V fixed or adjustable output RoHS compliant available Typical Application www.acutechnology.com AQ1541 Acutechnology Semiconductor Inc. AQ1541 Pin Configuration Pin Descriptions Pin Name VIN VOUT Ground/Adjust ENABLE Function Accepts + VCC Regulated Output - VCC for fixed option / Adjust pin for adjustable option Active high, ENABLE > (0.5V + VOUT). Connect to VIN when not in use. Functional Block Diagram www.acutechnology.com 2 Rev. 2.2 September 13, 2005 Acutechnology Semiconductor Inc. AQ1541 Ordering Information Device AQ1541 AQ1541 AQ1541 AQ1541 AQ1541 AQ1541 AQ1541 AQ1541 Note: The Operating Tj 0C˚ ≤ 125C˚ 0C˚ ≤ 125C˚ 0C˚ ≤ 125C˚ 0C˚ ≤ 125C˚ 0C˚ ≤ 125C˚ 0C˚ ≤ 125C˚ 0C˚ ≤ 125C˚ 0C˚ ≤ 125C˚ %Tol 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 PKG Type SOT-223-4 SOT-223-4 SOT-223-4 SOT-223-4 SOT-223-4 SOT-223-4 SOT-223-4 SOT-223-4 VOUT 1.8V 1.8V 2.5V 2.5V 3.3V 3.3V ADJ ADJ Wrap T&R T&R T&R T&R T&R T&R T&R T&R Ordering Number AQ1541CY-S4-18-TR AQ1541CY-S4-18-TRL AQ1541CY-S4-25-TR AQ1541CY-S4-25-TRL AQ1541CY-S4-33-TR AQ1541CY-S4-33-TRL AQ1541CY-S4-AJ-TR AQ1541CY-S4-AJ-TRL TRL parts are Lead Free and RoHS compliant. Absolute Maximum Ratings Stress greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These stress ratings only, and functional operation of the device at these or any conditions beyond those indicated under recommended Operating Conditions is not implied. Exposure to “Absolute Maximum Rating” for extended periods may affect device reliability. Use of standard ESD handling precautions is required. Parameter Maximum VIN Maximum VEN Maximum IEN Power Dissipation (Internally limited) Maximum Junction Temperature Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering, 10 sec.) TO packages Lead Temperature (Soldering, 4sec.) SOT- 223 package 150 0 to 125 -65 to 150 300 300 °C °C °C °C °C Value 18 18 10 Units Volts Volts mA Thermal Management Thermal Resistance (Junction to TAB) SOT-223 Thermal Resistance (Junction to Ambient) SOT-223 (tab soldered to 1 in2 1 oz. copper PCB) www.acutechnology.com 3 Typical Value 15 Typical Value 46 Rev. 2.2 Units °C/W Units °C/W September 13, 2005 Acutechnology Semiconductor Inc. AQ1541 Electrical Specifications Electrical characteristics are guaranteed over the full temperature range 0ºC 1000uF) and the input is instantaneously shorted to ground, can damage occur. 6. Thermal Considerations When an integrated circuit operates with an appreciable current, its junction temperature is elevated. It is important to quantify its thermal limits in order to achieve acceptable performance and reliability. This limit is determined by summing the individual parts consisting of a series of temperature rises from the semiconductor junction to the operating environment. The heat generated at the device junction flows through the die to the die attach pad, through the lead frame to the surrounding case material, to the printed circuit board, and eventually to the ambient environment. The AQ1541 regulators have internal thermal shutdown to protect the device from overheating. Under all possible operating conditions, the junction temperature of the AQ1541 must be lower than 125°C. A heatsink may be required depending on the maximum power dissipation and maximum ambient temperature of the application. To determine if a heatsink is needed, the power dissipated by the regulator, PD, must be calculated: PD= (VIN-VOUT) IL where the IL is the load current. The next parameter which must be calculated is the maximum allowable temperature rise, T(max): T(max)=TJ(max)-TA(max) where TJ(max) is the maximum allowable junction temperature (125°C), and TA(max) is the maximum ambient temperature which will be encountered in the application. Using the calculated values for T(max) and PD, the maximum allowable value for the junction to ambient thermal resistance (θJA) can be calculated: θJA=T(max)/ PD If the maximum allowable value for θJA is found to be greater than the junction to ambient thermal resistance for the package used, no heatsink is needed since the package alone will dissipate enough heat to satisfy these requirements. www.acutechnology.com 9 Rev. 2.2 September 13, 2005 Acutechnology Semiconductor Inc. AQ1541 Package Dimensions SOT223-4 TetraPackTM Contact Information Acutechnology Semiconductor Inc. 3487 McKee Rd. Suite 52 San Jose CA , USA 95127 Disclaimer The information furnished by Acutechnology in this data sheet is believed to be accurate and reliable. However, Acutechnology assumes no responsibility for its use. Acutechnology reserves the right to change circuitry and specifications at any time without notification to the customer. TEL: FAX: website: (408) 259-2300 (408) 259-9160 www.acutechnology.com Life Support Policy Acutechnology Products are not designed or authorized for use as components in life support devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. TetraPack and AcuRef are trademarks of Acutechnology Semiconductor Inc www.acutechnology.com 10 Rev. 2.2 September 13, 2005