LM2773 Low-Ripple 1.8V/1.6V Spread-Spectrum Switched Capacitor Step-Down Regulator General Description Features The LM2773 is a switched capacitor step-down regulator that produces a selectable 1.8V or 1.6V output. It is capable of supplying loads up to 300mA. The LM2773 operates with an input voltage from 2.5V to 5.5V, accommodating 1-cell Li-Ion batteries and chargers. The LM2773 utilizes a regulated charge pump with gains of 2/3x and 1x. It has very low ripple and noise on both the input and output due to its pre-regulated 1.15MHz (typ.) switching frequency and spread spectrum operation. When output currents are low, the LM2773 automatically switches to a lowripple PFM regulation mode to maintain high efficiency over the entire load range. The LM2773 is available in National’s 0.5mm pitch 9-bump Micro-SMD (µSMD-9). ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Low-Noise Spread Spectrum Operation 1.8V/1.6V Selectable Output Voltage 2% Output Voltage Regulation > 75% Efficiency in 1.8V Mode Very Low Output Ripple: 10mV @ 300mA Output Currents up to 300mA 2.5V to 5.5V Input Voltage Range Shutdown Disconnects Load from VIN 1.15MHz Switching Frequency No Inductors…Small Solution Size Short Circuit and Thermal Protection 0.5mm pitch, µSMD-9 (1.511 × 1.511mm × 0.6mm) Applications ■ Power Supply for DSP's, Memory, and Microprocessors ■ Mobile Phones and Pagers ■ Digital Cameras, Portable Music Players, and Other Portable Electronic Devices Typical Application Circuit LM2773 Efficiency vs. Low-Dropout Linear Regulator (LDO) Efficiency 30047401 30047410 © 2008 National Semiconductor Corporation 300474 www.national.com LM2773 Low-Ripple 1.8V/1.6V Spread-Spectrum Switched Capacitor Step-Down Regulator January 22, 2008 LM2773 Connection Diagram and Package Mark Information 9-Bump Micro SMD (µSMD-9) NS Package Number TLA9ZZA, 0.5mm Pitch 1.511mm x 1.511mm x 0.6mm 30047402 Note 1: The actual physical placement of the package marking will vary from part to part. The package marking "X" designates the single digit date code. "V" is a NSC internal code for die traceability. Both will vary considerably. "DJ" identifies the device (part number, option, etc.). Pin Descriptions Pin # Name A1 C2- Flying Capacitor 2: Negative Terminal Description A2 VOUT Output Voltage A3 C1+ Flying Capacitor 1: Positive Terminal B1 GND Ground B2 EN Device Enable. Logic HIGH: Enabled, Logic LOW: Shutdown. B3 VIN Input Voltage. Recommended VIN Operating Range = 2.5V to 5.5V. C1 SEL Voltage Mode Select. Logic HIGH: VOUT = 1.6V, Logic LOW: VOUT = 1.8V C2 C1- Flying Capacitor 1: Negative Terminal C3 C2+ Flying Capacitor 2: Positive Terminal Order Information Output Voltages Order Number 1.8V/1.6V LM2773TL 1.8V/1.6V www.national.com LM2773TLX Package Mark ID XV DJ XV DJ 2 Package TLA9ZZA 9-Bump µSMD Supplied as: 1000 Units, Tape and Reel 4500 Units, Tape and Reel Operating Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. (Notes 2, 3) VIN Pin Voltage EN, SEL Pin Voltage Continuous Power Dissipation (Note 4) Junction Temperature (TJ-MAX) Storage Temperature Range Maximum Lead Temperature (Soldering, 10 sec.) ESD Rating (Note 5) Human Body Model: Input Voltage Range Recommended Load Current Range Junction Temperature (TJ) Range Ambient Temperature (TA) Range (Note 6) -0.3V to 6.0V -0.3V to (VIN+0.3V) w/ 6.0V max Internally Limited 2.5V to 5.5V 0mA to 300mA -30°C to +110°C -30°C to +85°C Thermal Properties 150°C -65°C to +150° C 265°C Electrical Characteristics LM2773 Absolute Maximum Ratings (Notes 2, 3) Junction-to-Ambient Thermal Resistance (θJA), µSMD-9 Package (Note 7) 75°C/W 2.5kV (Notes 3, 8) Limits in standard typeface are for TJ = 25°C. Limits in boldface type apply over the full operating junction temperature range (-30° C ≤ TJ ≤ +110°C) . Unless otherwise noted, specifications apply to the LM2773 Typical Application Circuit (pg. 1) with: VIN = 3.6V; V(EN) = 1.8V, V(SEL) = 0V, CIN = C1 = C2 = 1.0µF, COUT = 4.7µF. (Note 10) Symbol Parameter 1.8V Mode Output Voltage Regulation VOUT 1.6V Mode Output Voltage Regulation Condition 2.5V ≤ VIN ≤ 5.5V 0mA ≤ IOUT ≤ 300mA Min Typ Max 1.779 (−2%) 1.815 1.851 (+2%) 1.619 1.651 (+2%) Units V V(SEL) = 1.8V 2.5V ≤ VIN ≤ 5.5V 0mA ≤ IOUT ≤ 300mA 1.587 (−2%) 0mA ≤ IOUT ≤ 300mA VOUT/IOUT Output Load Regulation VOUT/VIN Output Line Regulation E Power Efficiency IOUT = 300mA IQ Quiescent Supply Current IOUT = 0mA (Note 11) 48 VR Fixed Frequency Output Ripple IOUT = 300mA 10 VR–PFM PFM–Mode Output Ripple IOUT < 40mA 12 ISD Shutdown Current V(EN) = 0V 0.1 0.625 µA FSW Switching Frequency 3.0V ≤ VIN ≤ 5.5V 1.15 1.50 MHz ROL Open-Loop Output Resistance IOUT = 300mA (Note 9) ICL Output Current Limit tON Turn-on Time 0.80 0.15 mV/mA 0.3 %/V 75 % 55 µA mV mV 1.0 Ω 500 mA 150 µs VIN = 5.5V 0V ≤ VOUT ≤ 0.2V (Note 13) EN, SEL Pins VIL Logic-low Input Voltage VIH Logic-high Input Voltage IIH Logic-high Input Current V(EN), V(SEL) = 1.8V (Note 12) IIL Logic-low Input Current V(EN), V(SEL) = 0V 2.5V ≤ VIN ≤ 5.5V EN, SEL Pins 2.5V ≤ VIN ≤ 5.5V 0 0.5 V 1.0 VIN V 5 µA 0.01 µA Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics tables. Note 3: All voltages are with respect to the potential at the GND pins. 3 www.national.com LM2773 Note 4: Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=150°C (typ.) and disengages at TJ=140°C (typ.). Note 5: The Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. MIL-STD-883 3015.7 Note 6: Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 110°C), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX). Note 7: Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists, special care must be paid to thermal dissipation issues. Note 8: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the most likely norm. Note 9: Open loop output resistance can be used to predict output voltage when, under low VIN and high IOUT conditions, VOUT falls out of regulation. VOUT = (Gain)VIN - (ROL x IOUT) Note 10: CIN, COUT, C1, C2: Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics. Note 11: VOUT is set to 1.9V during this test (Device is not switching). Note 12: There are 350kΩ pull-down resistors connected internally between the EN pin and GND and the SEL pin and GND. Note 13: Under the stated conditions, the maximum input current is equal to 2/3 the maximum output current. Block Diagram 30047403 www.national.com 4 Unless otherwise specified: VIN = 3.6V, CIN = C1 = C2 = 1.0µF, COUT = 4.7µF, V(EN) = 1.8V, V(SEL) = 0V, TA = 25°C. Capacitors are low-ESR multi-layer ceramic capacitors (MLCC's). Output Voltage vs. Input Voltage, 1.6V Mode Output Voltage vs. Input Voltage, 1.8V Mode 30047404 30047405 Output Voltage vs. Output Current, 1.8V Mode Output Voltage vs. Output Current, 1.6V Mode 30047406 30047407 5 www.national.com LM2773 Typical Performance Characteristics LM2773 Efficiency vs. Input Voltage, 1.8V Mode Efficiency vs. Input Voltage, 1.6V Mode 30047408 30047409 Shutdown Supply Current Operating Supply Current 30047412 30047411 Line Step 3.0V to 4.2V with Load = 300mA, 1.8V Mode Line Step 3.0V to 4.2V with Load = 300mA, 1.6V Mode 30047413 30047414 CH1: VIN; Scale: 1V/Div, DC Coupled CH2: VOUT; Scale: 20mV/Div, AC Coupled Time scale: 10ms/Div www.national.com CH1: VIN; Scale: 1V/Div, DC Coupled CH2: VOUT; Scale: 20mV/Div, AC Coupled Time scale: 10ms/Div 6 Load Step 300mA to 0mA, VIN = 3.6V, 1.8V Mode 30047415 30047416 CH2: VOUT; Scale: 100mV/Div, DC Coupled, Offset 1.834V CH4: IOUT; Scale: 100mA/Div Time scale: 4ms/Div CH2: VOUT; Scale: 100mV/Div, DC Coupled, Offset 1.834V CH4: IOUT; Scale: 100mA/Div Time scale: 4ms/Div Load Step 0mA to 300mA, VIN = 3.6V, 1.6V Mode Load Step 300mA to 0mA, VIN = 3.6V, 1.6V Mode 30047417 30047418 CH2: VOUT; Scale: 100mV/Div, DC Coupled, Offset 1.633V CH4: IOUT; Scale: 100mA/Div Time scale: 4ms/Div CH2: VOUT; Scale: 100mV/Div, DC Coupled, Offset 1.633V CH4: IOUT; Scale: 100mA/Div Time scale: 4ms/Div 1.8V Mode Startup, Load = 300mA 1.6V Mode Startup, Load = 300mA, VSEL = VIN 30047419 30047420 CH1: VEN; Scale: 5V/Div, DC Coupled CH2: VOUT; Scale: 500mV/Div, DC Coupled Time scale: 10µs/Div CH1: VEN; Scale: 5V/Div, DC Coupled CH2: VOUT; Scale: 500mV/Div, DC Coupled Time scale: 10µs/Div 7 www.national.com LM2773 Load Step 0mA to 300mA, VIN = 3.6V, 1.8V Mode LM2773 the efficiency graph in the Typical Performance Characteristics section for detailed efficiency data. The transition between the gain of 1x and 2/3x is clearly distinguished by the sharp discontinuity in the efficiency curve. Operation Description OVERVIEW The LM2773 is a switched capacitor converter that produces a selectable 1.8V or 1.6V regulated output. The core of the part is a highly efficient charge pump that utilizes fixed frequency pre-regulation, Pulse Frequency Modulation, and spread spectrum to minimize conducted noise and power losses over wide input voltage and output current ranges. A description of the principal operational characteristics of the LM2773 is detailed in the Circuit Description, and Efficiency Performance sections. These sections refer to details in the Block Diagram. SHUTDOWN AND VOLTAGE SELECT The LM2773 is in shutdown mode when the voltage on the enable pin (EN) is logic-low. In shutdown, the LM2773 draws virtually no supply current. When in shutdown, the output of the LM2773 is completely disconnected from the input. Internal feedback resistors pull the output voltage down to 0V during shutdown. The SEL pin sets the output voltage at either 1.8V or 1.6V. A logic-low voltage on the SEL pin will place the output of the LM2773 in the 1.6V mode, and a logic-high voltage on the SEL pin will place it into the 1.8V mode. There are 350kΩ pull-down resistors connected internally between the EN pin and GND and the SEL pin and GND. CIRCUIT DESCRIPTION The core of the LM2773 is a two-phase charge pump controlled by an internally generated non-overlapping clock. The charge pump operates by using external flying capacitors C1 and C2 to transfer charge from the input to the output. The LM2773 will operate in a 1x Gain, with the input current being equal to the load current, when the input voltage is at or below 3.5V (typ.) for 1.8V mode or 3.3V (typ.) for 1.6V mode. At input voltages above 3.5V (typ.) or 3.3V (typ.) for the respective voltage mode selected, the part utilizes a gain of 2/3x, resulting in an input current equal to 2/3 times the load current. The two phases of the switched capacitor switching cycle will be referred to as the "charge phase" and the "discharge phase". During the charge phase, the flying capacitor is charged by the input supply. After half of the switching cycle [ t = 1/(2×FSW) ], the LM2773 switches to the discharge phase. In this configuration, the charge that was stored on the flying capacitors in the charge phase is transferred to the output. The LM2773 uses fixed frequency pre-regulation to regulate the output voltage to 1.8V during moderate to high load currents. The input and output connections of the flying capacitors are made with internal MOS switches. Pre-regulation limits the gate drive of the MOS switch connected between the voltage input and the flying capacitors. Controlling the on resistance of this switch limits the amount of charge transferred into and out of each flying capacitor during the charge and discharge phases, and in turn helps to keep the output ripple very low. When output currents are low (<40mA typ.), the LM2773 automatically switches to a low-ripple Pulse Frequency Modulation (PFM) form of regulation. In PFM mode, the flying capacitors stay in the discharge phase until the output voltage drops below a predetermined trip point. When this occurs, the flying capacitors switch back to the charge phase. After being charged, the flying capacitors repeat the process of staying in the discharge phase and switching to the charge phase when necessary. The LM2773 utilizes spread spectrum operation to distrubute the peak radiated energy of the device over a wider frequency band, reducing electromagnetic interference (EMI). Spread spectrum is used during all modes of operation for the LM2773. SOFT START The LM2773 employs soft start circuitry to prevent excessive input inrush currents during startup. At startup, the output voltage gradually rises from 0V to the nominal output voltage. This occurs in 150µs (typ.). Soft-start is engaged when the part is enabled. THERMAL SHUTDOWN Protection from damage related to overheating is achieved with a thermal shutdown feature. When the junction temperature rises to 150°C (typ.), the part switches into shutdown mode. The LM2773 disengages thermal shutdown when the junction temperature of the part is reduced to 140°C (typ.). Due to the high efficiency of the LM2773, thermal shutdown and/or thermal cycling should not be encountered when the part is operated within specified input voltage, output current, and ambient temperature operating ratings. If thermal cycling is seen under these conditions, the most likely cause is an inadequate PCB layout that does not allow heat to be sufficiently dissipated out of the µSMD package. CURRENT LIMIT PROTECTION The LM2773 charge pump contains current limit protection circuitry that protects the device during VOUT fault conditions where excessive current is drawn. Output current is limited to 500mA (typ). Application Information RECOMMENDED CAPACITOR TYPES The LM2773 requires 4 external capacitors for proper operation. Surface-mount multi-layer ceramic capacitors are recommended. These capacitors are small, inexpensive and have very low equivalent series resistance (ESR, ≤ 15mΩ typ.). Tantalum capacitors, OS-CON capacitors, and aluminum electrolytic capacitors generally are not recommended for use with the LM2773 due to their high ESR, as compared to ceramic capacitors. For most applications, ceramic capacitors with an X7R or X5R temperature characteristic are preferred for use with the LM2773. These capacitors have tight capacitance tolerance (as good as ±10%) and hold their value over temperature (X7R: ±15% over -55°C to 125°C; X5R: ±15% over -55°C to 85°C). Capacitors with a Y5V or Z5U temperature characteristic are generally not recommended for use with the LM2773. These types of capacitors typically have wide capacitance tolerance EFFICIENCY PERFORMANCE Charge-pump efficiency is derived in the following two ideal equations (supply current and other losses are neglected for simplicity): IIN = G × IOUT E = (VOUT × IOUT) ÷ (VIN × IIN) = VOUT ÷ (G × VIN) In the equations, G represents the charge pump gain. Efficiency is at its highest as G×VIN approaches VOUT. Refer to www.national.com 8 Manufacturer INPUT CAPACITOR AND INPUT VOLTAGE RIPPLE The input capacitor (CIN) is a reservoir of charge that aids a quick transfer of charge from the supply to the flying capacitors during the charge phase of operation. The input capacitor helps to keep the input voltage from drooping at the start of the charge phase when the flying capacitors are connected to the input. It also filters noise on the input pin, keeping this noise out of sensitive internal analog circuitry that is biased off the input line. Much like the relationship between the output capacitance and output voltage ripple, input capacitance has a dominant, first-order effect on input ripple magnitude. Increasing (decreasing) the input capacitance will result in a proportional decrease (increase) in input voltage ripple. Input voltage, output current, and flying capacitance also will affect input ripple levels to some degree. In typical high-current applications, a 1µF low-ESR ceramic capacitor is recommended on the input. Different input capacitance values can be used to reduce ripple, shrink the solution size, and/or cut the cost of the solution. But changing the input capacitor may also require changing the flying capacitor and/or output capacitor to maintain good overall circuit performance. Performance of the LM2773 with different capacitor setups is discussed below in Recommended Capacitor Configurations. Contact Information AVX www.avx.com Murata www.murata.com Taiyo-Yuden www.t-yuden.com TDK www.component.tdk.com Vishay-Vitramon www.vishay.com FLYING CAPACITORS The flying capacitors (C1, C2) transfer charge from the input to the output. Flying capacitance can impact both output current capability and ripple magnitudes. If flying capacitance is too small, the LM2773 may not be able to regulate the output voltage when load currents are high. On the other hand, if the flying capacitance is too large, the flying capacitor might overwhelm the input and output capacitors, resulting in increased input and output ripple. In typical high-current applications, 1µF low-ESR ceramic capacitors are recommended for the flying capacitors. Polarized capacitors (tantalum, aluminum electrolytic, etc.) must not be used for the flying capacitor, as they could become reversebiased during LM2773 operation. OUTPUT CAPACITOR AND OUTPUT VOLTAGE RIPPLE The output capacitor in the LM2773 circuit (COUT) directly impacts the magnitude of output voltage ripple. Other prominent factors also affecting output voltage ripple include input voltage, output current and flying capacitance. Due to the complexity of the regulation topology, providing equations or models to approximate the magnitude of the ripple can not be easily accomplished. But one important generalization can be made: increasing (decreasing) the output capacitance will result in a proportional decrease (increase) in output voltage ripple. In typical high-current applications, a 4.7µF low-ESR ceramic output capacitor is recommended. Different output capacitance values can be used to reduce ripple, shrink the solution size, and/or cut the cost of the solution. But changing the output capacitor may also require changing the flying capacitor and/or input capacitor to maintain good overall circuit performance. Performance of the LM2773 with different capacitor setups in discussed in the section Recommended Capacitor Configurations. High ESR in the output capacitor increases output voltage ripple. If a ceramic capacitor is used at the output, this is usually not a concern because the ESR of a ceramic capacitor is typically very low and has only a minimal impact on ripple magnitudes. If a different capacitor type with higher ESR is used (tantalum, for example), the ESR could result in high ripple. To eliminate this effect, the net output ESR can be significantly reduced by placing a low-ESR ceramic capacitor in RECOMMENDED CAPACITOR CONFIGURATIONS The data in Table 1 can be used to assist in the selection of capacitance configurations that best balances solution size and cost with the electrical requirements of the application. As previously discussed, input and output ripple voltages will vary with output current and input voltage. The numbers provided show expected ripple voltage with VIN = 3.6V and a load current of 300mA. The table offers a first look at approximate ripple levels and provides a comparison of different capacitor configurations, but is not intended to be a guarantee of performance. With any capacitance configuration chosen, always verify that the performance of the ripple waveforms are suitable for the intended application. The same capacitance value must be used for all the flying capacitors. 9 www.national.com LM2773 parallel with the primary output capacitor. The low ESR of the ceramic capacitor will be in parallel with the higher ESR, resulting in a low net ESR based on the principles of parallel resistance reduction. (+80%, -20%) and vary significantly over temperature (Y5V: +22%, -82% over -30°C to +85°C range; Z5U: +22%, -56% over +10°C to +85°C range). Under some conditions, a 1µFrated Y5V or Z5U capacitor could have a capacitance as low as 0.1µF. Such detrimental deviation is likely to cause Y5V and Z5U capacitors to fail to meet the minimum capacitance requirements of the LM2773. Net capacitance of a ceramic capacitor decreases with increased DC bias. This degradation can result in lower capacitance than expected on the input and/or output, resulting in higher ripple voltages and currents. Using capacitors at DC bias voltages significantly below the capacitor voltage rating will usually minimize DC bias effects. Consult capacitor manufacturers for information on capacitor DC bias characteristics. Capacitance characteristics can vary quite dramatically with different application conditions, capacitor types, and capacitor manufacturers. It is strongly recommended that the LM2773 circuit be thoroughly evaluated early in the design-in process with the mass-production capacitors of choice. This will help ensure that any such variability in capacitance does not negatively impact circuit performance. The table below lists some leading ceramic capacitor manufacturers. LM2773 TABLE 1. LM2773 Performance with Different Capacitor Configurations, 1.8V Mode (Note 14) Note 14: Refer to the text in the Recommended Capacitor Configurations section for detailed information on the data in this table CAPACITOR CONFIGURATION (VIN = 3.6V) Layout Guidelines TYPICAL OUTPUT RIPPLE CIN = 1µF, COUT = 4.7µF, C1, C2 = 1µF 10mV CIN = 1µF, COUT = 2.2µF, C1, C2 = 1µF 16mV CIN = 0.47µF, COUT = 4.7µF, C1, C2 = 1µF 12mV CIN = 0.47µF, COUT = 3.3µF, C1, C2 = 1µF 12mV CIN = 0.47µF, COUT = 3.3µF, C1, C2 = 0.47µF 13mV www.national.com Proper board layout will help to ensure optimal performance of the LM2773 circuit. The following guidelines are recommended: • Place capacitors as close to the LM2773 as possible, and preferably on the same side of the board as the IC. • Use short, wide traces to connect the external capacitors to the LM2773 to minimize trace resistance and inductance. • Use a low resistance connection between ground and the GND pin of the LM2773. Using wide traces and/or multiple vias to connect GND to a ground plane on the board is most advantageous. 10 LM2773 Physical Dimensions inches (millimeters) unless otherwise noted TLA09ZZA: 9-Bump Micro-SMD Package x1: 1.511mm x2: 1.511mm x3: 0.6mm 11 www.national.com LM2773 Low-Ripple 1.8V/1.6V Spread-Spectrum Switched Capacitor Step-Down Regulator Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS, IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS. EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. Copyright© 2008 National Semiconductor Corporation For the most current product information visit us at www.national.com National Semiconductor Americas Technical Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Technical Support Center Email: [email protected] German Tel: +49 (0) 180 5010 771 English Tel: +44 (0) 870 850 4288 National Semiconductor Asia Pacific Technical Support Center Email: [email protected] National Semiconductor Japan Technical Support Center Email: [email protected]