MIC23250 4MHz Dual 400mA Synchronous Buck Regulator with HYPER LIGHT LOAD™ General Description Features The MIC23250 is a high efficiency 4MHz dual 400mA synchronous buck regulator with Hyper Light Load™. Hyper Light Load™ provides all the advantages of standard light load modes, such as low quiescent current and high efficiency but also allows the use of very small output capacitors to maintain low output ripple voltage throughout the entire load range. This benefit is not possible with other light load mode types as they trade off control speed for low standby currents. With Hyper Light Load™, the output capacitor can be reduced by up to a factor of 20 saving cost and valuable board space. The tiny package (2mm x 2mm Thin MLF®) of MIC23250 also saves crucial board space by using only six external components while regulating two independent outputs up to 400mA each. The device is designed for use with a 1µH inductor and a 4.7µF output capacitor that enables a sub-1mm height. The MIC23250 has a very low quiescent current of 35µA and can achieve over 85% efficiency at 1mA. At higher loads the MIC23250 provides a constant switching frequency around 4MHz while providing peak efficiencies up to 94%. The MIC23250 fixed output voltage option is available in a 10-pin 2mm x 2mm Thin MLF® with a junction operating range from –40°C to +125°C. The adjustable output voltage option will soon be available in Q2/Q3 2008. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • Input voltage range: 2.7V to 5.5V • Dual output current 400mA/400mA • Hyper Light Load™ mode – 35µA dual quiescent current – 1µH inductor with a 4.7µF capacitor • 4MHz in PWM operation • Ultra fast transient response • Low voltage output ripple – 20mVpp in Hyper Light Load™ mode – 3mV output voltage ripple in full PWM mode • Up to 94% peak efficiency and 85% efficiency at 1mA • Fully integrated MOSFET switches • Micropower shutdown • Thermal shutdown and current limit protection • Fixed output:10-pin 2mm x 2mm Thin MLF® • Adjustable output:12-pin 2.5mm x 2.5mm Thin MLF® (Available in Q2/Q3 2008) • –40°C to +125°C junction temperature range Applications • Mobile handsets • Portable media players • Portable navigation devices (GPS) • WiFi/WiMax/WiBro modules • Digital cameras • Wireless LAN cards • USB Powered Devices ___________________________________________________________________________________________________________ Typical Application Efficiency VOUT = 1.8V 100 VIN = 3.0V 90 VIN = 2.7V 80 70 VIN = 4.2V 60 VIN = 3.6V 50 40 30 20 10 0 1 L = 1µH COUT = 4.7µF 10 100 LOAD (mA) 1000 Hyper Light Load is a trademark of Micrel, Inc. MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com December 2007 M9999-121707-A Micrel, Inc. MIC23250 Ordering Information Part Number Marking Nominal Output Voltage 1 Nominal Output Voltage 2 Junction Temp. Range Package Lead Finish MIC23250-GFHYMT WV1 1.575V 1.8V –40° to +125°C 10-Pin 2mm x 2mm Thin MLF® Pb-Free MIC23250-G4YMT WV5 1.8V 1.2V –40° to +125°C 10-Pin 2mm x 2mm Thin MLF® Pb-Free MIC23250-C4YMT WV2 1.0V 1.2V –40° to +125°C 10-Pin 2mm x 2mm Thin MLF® Pb-Free MIC23250-3BYMT WV3 1.1V 0.9V –40° to +125°C 10-Pin 2mm x 2mm Thin MLF® Pb-Free MIC23250-W4YMT WV4 1.6V 1.2V –40° to +125°C 10-Pin 2mm x 2mm Thin MLF® Pb-Free MIC23250-Adj* TBD ADJ ADJ –40° to +125°C 12-Pin 2.5mm x 2.5mm Thin MLF® Pb-Free Note: * Available Q2/Q3 2008 Pin Configuration SNS1 1 10 SNS2 EN1 2 9 EN2 AGND 3 8 AVIN SW1 4 7 SW2 PGND 5 6 VIN 10-Pin 2mm x 2mm Thin MLF® (MT) (Top View) Pin Description Pin Number Pin Name 1 SNS1 2 EN1 3 AGND 4 SW1 5 PGND 6 VIN Pin Name Sense 1 (Input): Error amplifier input. Connect to feedback resistor network to set output 1 voltage. Enable 1 (Input): Logic low will shut down output 1. Logic high powers up output 1. Do not leave unconnected. Analog Ground. Must be connected externally to PGND. Switch Node 1 (Output): Internal power MOSFET output. Power Ground. Supply Voltage (Power Input): Requires close bypass capacitor to PGND. 7 SW2 Switch Node 2 (Output): Internal power MOSFET output. 8 AVIN Supply Voltage (Power Input): Analog control circuitry. Connect to VIN. 9 EN2 Enable 2 (Input): Logic low will shut down output 2. Logic high powers up output 2. Do not leave unconnected. 10 SNS2 December 2007 Sense 2 (Input): Error amplifier input. Connect to feedback resistor network to set output 2 voltage. 2 M9999-121707-A Micrel, Inc. MIC23250 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) .........................................................6V Output Switch Voltage (VSW) ............................................6V Logic Input Voltage (VEN) .................................. –0.3V to VIN Storage Temperature Range (Ts)..............–65°C to +150°C ESD Rating(3) .................................................................. 2kV Supply Voltage (VIN)......................................... 2.7V to 5.5V Logic Input Voltage (VEN) .................................. –0.3V to VIN Junction Temperature (TJ) ..................–40°C ≤ TJ ≤ +125°C Thermal Resistance 2mm x 2mm Thin MLF®-10 (θJA)........................70°C/W Electrical Characteristics(4) TA = 25°C with VIN = VEN = 3.6V; L = 1µH; COUT = 4.7µF; IOUT = 20mA; only one channel power is enabled, unless otherwise specified. Bold values indicate –40°C< TJ < +125°C. Parameter Supply Voltage Range Under-Voltage Lockout Threshold UVLO Hysteresis Quiescent Current, Hyper LL mode Shutdown Current Output Voltage Accuracy Current Limit in PWM Mode Output Voltage Line Regulation Output Voltage Load Regulation Maximum Duty Cycle PWM Switch ON-Resistance Frequency Soft Start Time Enable Threshold Enable Input Current Over-temperature Shutdown Over-temperature Shutdown Hysteresis Condition Min (turn-on) 2.7 2.45 Typ Max Units 2.55 5.5 2.65 V V 60 VOUT1, 2 (both Enabled), IOUT1, 2 = 0mA , SNS1, 2 >1.2 * VOUT1, 2 Nominal VEN1, 2 = 0V; VIN = 5.5V VIN = 3.6V, ILOAD = 20mA SNS = 0.9*VOUT NOM VIN = 3.0V to 5.5V, ILOAD = 20mA 20mA < ILOAD < 400mA, VIN = 3.6V SNS ≤ VNOM, VOUT = 1.8V, VIN = 2.7V ISW = 100mA PMOS ISW = -100mA NMOS ILOAD = 120mA VOUT = 90% –2.5 0.410 80 3.4 0.5 mV 35 50 µA 0.01 4 +2.5 1 µA % A %/V % 0.65 0.4 0.5 86 0.6 0.8 4 260 0.8 0.1 160 40 4.6 1.2 2 % Ω Ω MHz µs V µA °C °C Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model: 1.5kΩ in series with 100pF. 4. Specification for packaged product only. December 2007 3 M9999-121707-A Micrel, Inc. MIC23250 Typical Characteristics 50 45 Quiescent Current vs. Input Voltage 10 L = 1µH COUT = 4.7µF 0 2.7 3.2 3.7 4.2 4.7 5.2 5.7 INPUT VOLTAGE (V) Frequency vs. Temperature 0.01 1 1.90 1.88 1.86 1.84 4.5 1.82 1.80 4.0 3.5 L = 1µH COUT = 4.7µF Load = 120mA 20 40 60 80 TEMPERATURE (°C) Output Voltage vs. Temperature 1.72 1.70 1 1.2 L = 1µH COUT = 4.7µF Load = 120mA VIN = 3.6V 10 100 1000 OUTPUT CURRENT (mA) Output Voltage vs. Output Current 700 1.82 1.80 1.78 Load = 300mA 1.76 Load = 50mA Load = 400mA 1.74 VIN = 3.6V 10 100 1000 OUTPUT CURRENT (mA) Enable Threshold vs. Temperature Current Limit vs. Input Voltage 1.000 0.950 0.925 0.6 0.900 L = 1µH COUT = 4.7µF 20 40 60 80 TEMPERATURE (°C) VIN = 3.0V 90 VIN = 2.7V 80 VIN = 3.6V 70 VIN = 4.2V 60 50 L = 1µH COUT = 4.7µF 5.7 40 30 20 10 0 1 Enable ON Enable OFF 0.875 0.4 100 600 Enable Threshold vs. Input Voltage 0.975 VIN = 5.5V 0.825 VIN = 3.6V VOUT = 1.8V Load = 150mA 0.800 2.7 3.2 3.7 4.2 4.7 5.2 5.7 INPUT VOLTAGE (V) Efficiency VOUT = 1.8V Efficiency VOUT = 1.8V 650 December 2007 1.72 1.70 2.7 3.2 3.7 4.2 4.7 5.2 5.7 INPUT VOLTAGE (V) 0.8 VIN = 2.7V 0 Load = 1mA Load = 10mA Load = 150mA VIN = 4.2V 0.850 20 40 60 80 TEMPERATURE (°C) 10 100 1000 OUTPUT CURRENT (mA) 1.90 L = 1µH 1.88 COUT = 4.7µF 1.86 1.84 VOUT1 = 1.575V 550 2.7 3.2 3.7 4.2 4.7 5.2 INPUT VOLTAGE (V) 0.01 1 VIN = 3.6V VOUT = 1.8V COUT = 4.7µF Output Voltage vs. Input Voltage VIN = 3.0V 0.2 1.5 0.1 VOUT = 1.8V L = 1µH COUT = 4.7µF 1.0 VIN = 3.6V VOUT2 = 1.8V 1.7 1.78 1.76 1.74 L = 2.2µH VIN = 4.2V 0.1 10 5 1.6 1 L = 1µH 15 1.8 L = 4.7µH 4MHz 1 25 20 1.9 Switching Frequency vs. Output Current VIN = 3.0V 35 30 3.0 10 4MHz 40 5.0 Switching Frequency vs. Output Current 100 90 L = 1.5µH 80 70 L = 1.0µH 60 50 L = 0.47µH 40 30 L = 1µH COUT = 4.7µF 10 100 LOAD (mA) 4 1000 20 10 0 1 VIN = 3.6V COUT = 4.7µF 10 100 LOAD (mA) 1000 M9999-121707-A Micrel, Inc. MIC23250 Typical Characteristics (Continued) Efficiency VOUT = 1.575V 100 VIN = 3.0V 90 VIN = 2.7V 100 90 80 VIN = 3.3V 80 70 VIN = 4.2V 60 30 20 10 L = 1µH COUT = 4.7µF 10 100 LOAD (mA) December 2007 VIN = 4.2V 70 VIN = 3.6V 60 VIN = 3.6V 50 40 0 1 Dual Output Efficiency 1000 50 40 VOUT1 = 1.575V 30 VOUT2 = 1.8V 20 Load1 = Load2 L1 = L2 = 1µH 10 COUT1 = COUT2 = 4.7µF 0 1 10 100 LOAD (mA) 5 1000 M9999-121707-A Micrel, Inc. MIC23250 Functional Characteristics December 2007 6 M9999-121707-A Micrel, Inc. MIC23250 Functional Characteristics (Continued) December 2007 7 M9999-121707-A Micrel, Inc. MIC23250 Functional Characteristics (Continued) December 2007 8 M9999-121707-A Micrel, Inc. MIC23250 Functional Diagram MIC23250 Simplified Block Diagram December 2007 9 M9999-121707-A Micrel, Inc. MIC23250 Functional Description VIN The VIN provides power to the internal MOSFETs for the switch mode regulator along with the current limit sensing. The VIN operating range is 2.7V to 5.5V so an input capacitor with a minimum of 6.3V voltage rating is recommended. Due to the high switching speed, a minimum of 2.2µF bypass capacitor placed close to VIN and the power ground (PGND) pin is required. Based upon size, performance and cost, a TDK C1608X5R0J476K, size 0603, 4.7µF ceramic capacitor is highly recommended for most applications. Refer to the layout recommendations for details. SNS1/SNS2 The SNS pin (SNS1 or SNS2) is connected to the output of the device to provide feedback to the control circuitry. A minimum of 2.2µF bypass capacitor should be connected in shunt with each output. Based upon size, performance and cost, a TDK C1608X5R0J476K, size 0603, 4.7µF ceramic capacitor is highly recommended for most applications. In order to reduce parasitic inductance, it is good practice to place the output bypass capacitor as close to the inductor as possible. The SNS connection should be placed close to the output bypass capacitor. Refer to the layout recommendations for more details. AVIN The analog VIN (AVIN) provides power to the analog supply circuitry. AVIN and VIN must be tied together. Careful layout should be considered to ensure high frequency switching noise caused by VIN is reduced before reaching AVIN. A 0.01µF bypass capacitor placed as close to AVIN as possible is recommended. See layout recommendations for details. PGND The power ground (PGND) is the ground path for the high current in PWM mode. The current loop for the power ground should be as small as possible and separate from the Analog ground (AGND) loop. Refer to the layout recommendations for more details. EN1/EN2 The enable pins (EN1 and EN2) control the on and off states of outputs 1 and 2, respectively. A logic high signal on the enable pin activates the output voltage of the device. A logic low signal on each enable pin deactivates the output. MIC23250 features built-in soft-start circuitry that reduces in-rush current and prevents the output voltage from overshooting at start up. AGND The signal ground (AGND) is the ground path for the biasing and control circuitry. The current loop for the signal ground should be separate from the Power ground (PGND) loop. Refer to the layout recommendations for more details. SW1/SW2 The switching pin (SW1 or SW2) connects directly to one end of the inductor (L1 or L2) and provides the current path during switching cycles. The other end of the inductor is connected to the load and SNS pin. Due to the high speed switching on this pin, the switch node should be routed away from sensitive nodes. December 2007 10 M9999-121707-A Micrel, Inc. Applications Information The MIC23250 is designed for high performance with a small solution size. With a dual 400mA output inside a tiny 2mm x 2mm Thin MLF® package and requiring only six external components, the MIC23250 meets today’s miniature portable electronic device needs. While small solution size is one of its advantages, the MIC23250 is big in performance. Using the Hyper Light Load™ switching scheme, the MIC23250 is able to maintain high efficiency throughout the entire load range while providing ultra-fast load transient response. Even with all the given benefits, the MIC23250 can be as easy to use as linear regulators. The following sections provide an over view of implementing MIC23250 into related applications Input Capacitor A minimum of 2.2µF ceramic capacitor should be placed close to the VIN pin and PGND pin for bypassing. A TDK C1608X5R0J476K, size 0603, 4.7µF ceramic capacitor is recommended based upon performance, size and cost. A X5R or X7R temperature rating is recommended for the input capacitor. Y5V temperature rating capacitors, aside from losing most of their capacitance over temperature, can also become resistive at high frequencies. This reduces their ability to filter out high frequency noise. Output Capacitor The MIC23250 was designed for use with a 2.2µF or greater ceramic output capacitor. Increasing the output capacitance will lower output ripple and improve load transient response but could increase solution size or cost. A low equivalent series resistance (ESR) ceramic output capacitor such as the TDK C1608X5R0J476K, size 0603, 4.7µF ceramic capacitor is recommended based upon performance, size and cost. Either the X7R or X5R temperature rating capacitors are recommended. The Y5V and Z5U temperature rating capacitors, aside from the undesirable effect of their wide variation in capacitance over temperature, become resistive at high frequencies. Inductor Selection Inductor selection will be determined by the following (not necessarily in the order of importance); • Inductance • Rated current value • Size requirements • DC resistance (DCR) The MIC23250 was designed for use with an inductance range from 0.47µH to 4.7µH. Typically, a 1µH inductor is recommended for a balance of transient response, efficiency and output ripple. For faster transient response a 0.47µH inductor may be used. For lower output ripple, a 4.7µH is recommended. Maximum current ratings of the inductor are generally December 2007 MIC23250 given in two methods; permissible DC current and saturation current. Permissible DC current can be rated either for a 40°C temperature rise or a 10% to 20% loss in inductance. Ensure the inductor selected can handle the maximum operating current. When saturation current is specified, make sure that there is enough margin so that the peak current of the inductor does not cause it to saturate. Peak current can be calculated as follows: ⎡ ⎛ 1 − VOUT / VIN I PEAK = ⎢I OUT + VOUT ⎜⎜ ⎝ 2×f ×L ⎣ ⎞⎤ ⎟⎟⎥ ⎠⎦ As shown by the previous calculation, the peak inductor current is inversely proportional to the switching frequency and the inductance; the lower the switching frequency or the inductance the higher the peak current. As input voltage increases the peak current also increases. The size of the inductor depends on the requirements of the application. Refer to the Application Circuit and Bill of Material for details. DC resistance (DCR) is also important. While DCR is inversely proportional to size, DCR can represent a significant efficiency loss. Refer to the Efficiency Considerations. Compensation The MIC23250 is designed to be stable with a 0.47µH to 4.7µH inductor with a minimum of 2.2µF ceramic (X5R) output capacitor. Efficiency Considerations Efficiency is defined as the amount of useful output power, divided by the amount of power supplied. ⎛V ×I Efficiency _ % = ⎜⎜ OUT OUT ⎝ VIN × I IN ⎞ ⎟⎟ × 100 ⎠ Maintaining high efficiency serves two purposes. It reduces power dissipation in the power supply, reducing the need for heat sinks and thermal design considerations and it reduces consumption of current for battery powered applications. Reduced current draw from a battery increases the devices operating time and is critical in hand held devices. There are two types of losses in switching converters; DC losses and switching losses. DC losses are simply the power dissipation of I2R. Power is dissipated in the high side switch during the on cycle. Power loss is equal to the high side MOSFET RDSON multiplied by the Switch Current squared. During the off cycle, the low side N-channel MOSFET conducts, also dissipating power. Device operating current also reduces efficiency. The product of the quiescent (operating) current and the supply voltage is another DC loss. The current required driving the gates on and off at a constant 4MHz frequency and the switching transitions make up the switching losses. 11 M9999-121707-A Micrel, Inc. MIC23250 Efficiency V OUT = 1.8V 100 VIN = 2.7V 80 60 VIN = 3.6V VIN = 3.3V 40 20 0 0.1 VOUT = 1.8V L = 1µH 1 10 100 LOAD (mA) 1000 The Figure above shows an efficiency curve. From no load to 100mA, efficiency losses are dominated by quiescent current losses, gate drive and transition losses. By using the Hyper Light Load™ mode the MIC23250 is able to maintain high efficiency at low output currents. Over 100mA, efficiency loss is dominated by MOSFET RDSON and inductor losses. Higher input supply voltages will increase the Gate-to-Source threshold on the internal MOSFETs, thereby reducing the internal RDSON. This improves efficiency by reducing DC losses in the device. All but the inductor losses are inherent to the device. In which case, inductor selection becomes increasingly critical in efficiency calculations. As the inductors are reduced in size, the DC resistance (DCR) can become quite significant. The DCR losses can be calculated as follows: L_Pd = IOUT2 × DCR From that, the loss in efficiency due to inductor resistance can be calculated as follows: ⎡ ⎛ VOUT × I OUT Efficiency _ Loss = ⎢1 − ⎜⎜ V ⎣⎢ ⎝ OUT × I OUT + L _ PD ⎞⎤ ⎟⎥ × 100 ⎟ ⎠⎦⎥ Efficiency loss due to DCR is minimal at light loads and gains significance as the load is increased. Inductor selection becomes a trade-off between efficiency and size in this case. comparator turns the PMOS off for a minimum-off-time until the output drops below the threshold. The NMOS acts as an ideal rectifier that conducts when the PMOS is off. Using a NMOS switch instead of a diode allows for lower voltage drop across the switching device when it is on. The asynchronous switching combination between the PMOS and the NMOS allows the control loop to work in discontinuous mode for light load operations. In discontinuous mode, the MIC23250 works in pulse frequency modulation (PFM) to regulate the output. As the output current increases, the off-time decreases, thus providing more energy to the output. This switching scheme improves the efficiency of MIC23250 during light load currents by only switching when it is needed. As the load current increases, the MIC23250 goes into continuous conduction mode (CCM) and switches at a frequency centered at 4MHz. The equation to calculate the load when the MIC23250 goes into continuous conduction mode may be approximated by the following formula: ⎛ V − VOUT × D ⎞ ⎟⎟ I LOAD = ⎜⎜ IN 2L × f ⎠ ⎝ As shown in the previous equation, the load at which MIC23250 transitions from Hyper Light Load™ mode to PWM mode is a function of the input voltage (VIN), output voltage (VOUT), duty cycle (D), inductance (L) and frequency (f). This is illustrated in the graph below. Since the inductance range of MIC23250 is from 0.47µH to 4.7µH, the device may then be tailored to enter Hyper Light Load™ mode or PWM mode at a specific load current by selecting the appropriate inductance. For example, in the graph below, when the inductance is 4.7µH the MIC23250 will transition into PWM mode at a load of approximately 4mA. Under the same condition, when the inductance is 1µH, the MIC23250 will transition into PWM mode at approximately 70mA. 10 Switching Frequency vs. Output Current L = 4.7µH 4MHz Hyper Light Load Mode™ The MIC23250 uses a minimum on and off time proprietary control loop (patented by Micrel). When the output voltage falls below the regulation threshold, the error comparator begins a switching cycle that turns the PMOS on and keeps it on for the duration of the minimumon-time. This increases the output voltage. If the output voltage is over the regulation threshold, then the error December 2007 1 L = 1µH L = 2.2µH 0.1 0.01 1 12 VIN = 3.6V VOUT = 1.8V COUT = 4.7µF 10 100 1000 OUTPUT CURRENT (mA) M9999-121707-A Micrel, Inc. MIC23250 MIC23250 Typical Application Circuit (Fixed 1.575V, 1.8V) Bill of Materials Item Part Number Manufacturer Description Qty C1, C2, C3 C1608X5R0J476K TDK(1) 4.7µF Ceramic Capacitor, 6.3V, X5R, Size 0603 3 (2) 0.01µF Ceramic Capacitor, 25V, X7R, Size 0603 1 Murata (3) 1µH, 0.8A, 190mΩ, L2mm x W1.25mm x H0.5mm Murata (3) C4 VJ0603Y103KXXAT LQM21PN1R0M00 LQH32CNR1R0M33 L1, L2 U1 Vishay 1µH, 1A, 60mΩ, L3.2mm x W2.5mm x H2.0mm LQM31P1R0M00 Murata(3) 1µH, 1.2A, 120mΩ, L3.2mm x W1.6mm x H0.95mm GFL251812T TDK(1) 1µH, 0.8A, 100mΩ, L2.5mm x W1.8mm x H1.35mm LQM31PNR47M00 Murata(3) 0.47µH, 1.4A, 80mΩ, L3.2mm x W1.6mm x H0.85mm (4) MIPF2520D1R5 FDK MIC23250-GFHYMT Micrel, Inc. 2 1.5µH, 1.5A, 70mΩ, L2.5mm x W2mm x H1.0mm 4MHz Dual 400mA Buck Regulator with Hyper Light Load™ Mode (5) 1 Notes: 1. TDK: www.tdk.com 2. Vishay: www.vishay.com 3. Murata: www.murata.com 4. FDK: www.fdk.co.jp 5. Micrel, Inc: www.micrel.com December 2007 13 M9999-121707-A Micrel, Inc. MIC23250 PCB Layout Recommendations Top Layer Bottom Layer December 2007 14 M9999-121707-A Micrel, Inc. MIC23250 Package Information ® 10-Pin 2mm x 2mm Thin MLF (MT) MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, 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. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2007 Micrel, Incorporated. December 2007 15 M9999-121707-A