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| AQ1117 Low Dropout 1 Amp Voltage Regulator Product Specification Revision 1.5 September 19, 2005 General Description The AQ1117 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. AQ1117 is offered in SOT-89 which has a lower thermal resistance and fits in smaller foot print than a standard SOT-223. With a dropout voltage of less than one volt, the AQ1117 can be used in applications where drop out voltage and size are an issue. To assure accuracy within 1.5% over temperature the heart of the AQ1117 is a selfcorrecting AcuRefTM 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. Applications * Graphic cards * PC motherboards * Switching power supply post-regulation * Telecom equipment * DVD video player Features * Featured in small SOT- 89 package * Vout tolerance 1.5% over temperature * 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 complaint available Typical Application www.acutechnology.com AQ1117 Acutechnology Semiconductor Inc. AQ1117 Pin Configuration SOT-89 Pin Descriptions Pin Name VIN VOUT Ground/Adjust Function Accepts + VCC Regulated Output - VCC for fixed option / Adjust pin for adjustable option Functional Block Diagram www.acutechnology.com 2 Rev. 1.5 September 20, 2005 Acutechnology Semiconductor Inc. AQ1117 Ordering Information Device AQ1117 AQ1117 AQ1117 AQ1117 AQ1117 AQ1117 AQ1117 AQ1117 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-89-3 SOT-89-3 SOT-89-3 SOT-89-3 SOT-89-3 SOT-89-3 SOT-89-3 SOT-89-3 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 AQ1117CY-M1-18-TR AQ1117CY-M1-18-TRL AQ1117CY-M1-25-TR AQ1117CY-M1-25-TRL AQ1117CY-M1-33-TR AQ1117CY-M1-33-TRL AQ1117CY-M1-AJ-TR AQ1117CY-M1-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 Power Dissipation (Internally limited) Maximum Junction Temperature Operating Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering, 4sec.) SOT packages 150 0 to 125 -65 to 150 300 C C C C Value 18 Units Volts Thermal Management Thermal Resistance (Junction to Tab) SOT-89 Typical Value 10 Units C/W Thermal Resistance (Junction to Ambient) SOT-89 (tab soldered to 1 in2 1 oz. copper PCB) Typical Value 30 Units C/W www.acutechnology.com 3 Rev. 1.5 September 20, 2005 Acutechnology Semiconductor Inc. AQ1117 Electrical Specifications Electrical characteristics are guaranteed over the full temperature range 0C Reference Voltage Adjust Pin Current (5) Adjust Pin Current (5) Change Minimum Load Current (5) Temperature Coefficient Temperature Stability RMS Output Noise (3) Ripple Rejection Ratio (4) Thermal Shutdown TSD Hysteresis Notes: (1) Low duty cycle pulse testing with Kelvin connections required. (2) Measure (VIN - VOUT) when VOUT, OR VREF = 1% (3) Bandwidth of 10Hz to 10kHz (4) 120Hz input ripple (5) Adjustable version only www.acutechnology.com 4 Rev. 1.5 September 20, 2005 Acutechnology Semiconductor Inc. AQ1117 Application Notes 1. Typical Application Notes: 1. Output voltage is 1.22V * (R2 +R1)/R1 2. Input and output capacitors should be located close to the device. 3. The AQ1117 will remain stable with C1 and C2 as low as 1.0F. Overall transient performance is improved with increased capacitance. 2. Stability An input capacitor is recommended. A 1.0F capacitor on the input is a suitable input bypassing for almost all applications. A larger capacitor is also suitable. In the adjustable version the "adjust" terminal can be bypassed to ground with a bypass capacitor (CADJ) to improve ripple rejection. This bypass capacitor prevents ripple from being amplified as the output voltage is increased. At any ripple frequency, the impedance of the CADJ should be less than R1 (being R1 the resistor between the output and the adjust pin) to prevent the ripple from being amplified: Z = 1/(2*fRIPPLE* CADJ) < R1 R1 is normally in the range of 1K. The output capacitor is critical in maintaining regular stability. The AQ1117 is stable with an output capacitor greater than. Of course any increase of the output capacitor will merely improve the loop stability and the load transient response. In the case of the adjustable regulator, when the CADJ is used, a larger output capacitance may be required. Tantalum Capacitors exhibit the best stability over a wide range of loads and are recommended. 3. Output Voltage The AQ1117 adjustable version develops a 1.22V reference voltage between the output and the adjust pin terminal. This voltage is applied across the resistor R1 to generate a constant current (I1). The current from the adjust terminal could introduce error to the output, but since it is very small (< 20A) compared with the current I1 and very constant with line and load changes, the error can be ignored. The constant current I1 then flows through resistor R2 and sets the output voltage to the desired level. www.acutechnology.com 5 Rev. 1.5 September 20, 2005 Acutechnology Semiconductor Inc. For fixed voltages the resistor R1 and R2 are integrated inside the devices. AQ1117 The AQ1117 regulates the voltage that appears between its output and ground pins or between its output and adjust pins. In some cases, line resistances can introduce errors to the voltage across the load. To obtain the best load regulation a few precautions are needed. For example it is important to minimize the line resistances to the load, so the load itself should be tied directly to the output terminal on the positive side and directly to the ground terminal on the negative side. When the adjustable regulator is used, the best performance is obtained with the positive side of the resistor R1 tied directly to the output terminal of the regulator rather than near the load. This will eliminate line drops from appearing effectively in series with the reference and degrading regulation. In addition the ground side of the resistor R2 can be returned near the ground of the load to provide remote ground sensing and improve load regulation. A capacitor (470pF) between the ADJ pin and system ground will enhance stability. 4. Protection Diodes Unlike older regulators, the AQ1117 family does not need any protection diodes between the adjustment pin and output or from the output to the input to prevent over-stressing the die. Internal resistors are limiting the internal current paths on the adjustment pin. Therefore, even with capacitors on the adjustment pin, no protection diode is needed to ensure device safety under short circuit conditions. External diodes between the input and output are not usually needed. Only if high value output capacitors are used (> 1000uF) and the input is instantaneously shorted to ground, can damage occur. 5. 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 AQ1117 regulators have internal thermal shutdown to protect the device from overheating. Under all possible operating conditions, the junction temperature of the AQ1117 must be lower than 125C. 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 (125C), 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 (JA) can be calculated: JA=T(max)/ PD If the maximum allowable value for JA 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 6 Rev. 1.5 September 20, 2005 Acutechnology Semiconductor Inc. AQ1117 Package Dimensions SOT-89 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. AcuRef is a trademark of Acutechnology Semiconductor Inc www.acutechnology.com 7 Rev. 1.5 September 20, 2005 |
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