MIC2141 Micropower Boost Converter General Description Features The MIC2141 is a micropower boost switching regulator • Implements low-power boost, SEPIC, or flyback that can operate from 3- or 4-cell nickel-metal-hydride • 2.2V to 14V input voltage batteries or a single Li-ion cell. This regulator employs a • 330kHz switching frequency constant 330kHz, fixed 18% duty-cycle, gated-oscillator • <2µA shutdown current architecture. • 70µA quiescent current The MIC2141 can be used in applications where the • 1.24V bandgap reference output voltage must be dynamically adjusted. The device features a control signal input which is used to • Typical output current 1mA to 10mA proportionally adjust the output voltage. The control signal • SOT23-5 package input has a gain of 6, allowing a 0.8V to 3.6V control signal to vary a 4.8V to 22V output. Applications The MIC2141 requires only three external components to operate and is available in a tiny 5-pin SOT-23 package for • LCD bias supply space and power-sensitive portable applications. The • CCD digital camera supply MIC2141 draws only 70µA of quiescent current and can operate with an efficiency exceeding 85%. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. ___________________________________________________________________________________________________________ Typical Application Control Voltage vs. Output Voltage 10µH Variable VOUT VC* (from DAC) 4.0 3.5 MIC2141 1 3.0 5 3 VC (V) 2 4 10µF 2.5 2.0 1.5 1.0 0.5 0 0 5 10 15 VOUT (V) 20 25 DAC-Controlled LCD Bias Voltage Supply 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 2006 1 M9999-122006 Micrel, Inc. MIC2141 Ordering Information Part Number Marking* Standard Pb-Free Standard Pb-Free MIC2141BM5 MIC2141YM5 SAAA SAAA Voltage Ambient Temperature Range Package Adj. –40° to +85°C 5-Pin SOT23 * Under bar symbol (_) may not be to scale. Pin Configuration 5-Pin SOT23 (BM5) 5-Pin SOT23 (YM5) Pin Description Pin Number Pin Name 1 IN 2 GND 3 SW Switch Node (Input): Internal MOSFET drain; 22V maximum. 4 FB Feedback (Input): Output voltage sense node. Compared to VC control input voltage. 5 VC Control (Input): Output voltage control signal input. Input voltage of 0.8V to3.6V is proportional to 4.8V to 22V output voltage (gain of 6). If the pin is not connected, the output voltage will be VIN – 0.5V. December 2006 Pin Function Input: +2.5V to +14V supply for internal circuity. Ground: Return for internal circuitry and internal MOSFET (switch) source. 2 M9999-122006 Micrel, Inc. MIC2141 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) .......................................................18V Switch Voltage (VSW)......................................................24V Feedback Voltage (VFB) .................................................24V Control Input Voltage (VC)(3) ............ VIN – 200mV ≤ VC ≤ 4V ESD Rating(4) .................................................................. 2kV Supply Voltage (VIN).......................................... 2.5V to 14V Switch Voltage (VSW)............................................ 3V to 22V Ambient Temperature (TA) .......................... –40°C to +85°C Junction Temperature Range (TJ)............. –40°C to +125°C Package Thermal Impedance SOT23-5 (θJA) ..................................................220°C/W Electrical Characteristics VIN = 3.6V; VOUT = 5V; IOUT = 1mA; TJ = 25°C, bold values indicate –40°C< TA < +85°C, unless noted. Parameter Condition Min Input Voltage Quiescent Current Typ 2.5 Switch off, VIN = 3.6V 70 Comparator Hysteresis Max Units 14 V 100 10 µA mV Control Voltage Gain (VOUT/VC) 2.5V ≤ VIN ≤ 12V, VOUT = 15V Controlled Output Voltage, Note 3 VC = 0.8V; 2.5V ≤ VIN ≤ 4.2V 4.85 5 5.15 V VC = 2.5V; 2.7V ≤ VIN ≤ 12V 14.55 15 15.45 V VC = 3.4V; 3.6V ≤ VIN ≤ 12V 19.4 20 20.6 V 6 Load Regulation 100µA ≤ IOUT ≤ 1mA, VOUT = 15V 0.25 1 % Line Regulation 2.5V ≤ VIN ≤ 12V; IOUT ≤ 1mA 0.05 0.2 %/V Switch on Resistance ISW = 100mA, VIN = 3.6V 4 Ω ISW = 100mA, VIN = 12V 2.5 Ω Oscillator Frequency 300 330 Oscillator Duty Cycle 15 18 360 kHz % Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating 3. VC = 4V sets VOUT to 24V (absolute maximum level on VSW ); VC must be ≤ VIN – 200mV. 4. Devices are ESD sensitive. Handling precautions recommended. December 2006 3 M9999-122006 Micrel, Inc. MIC2141 Typical Characteristics December 2006 4 M9999-122006 Micrel, Inc. MIC2141 Typical Characteristics (cont.) December 2006 5 M9999-122006 Micrel, Inc. MIC2141 Functional Diagram IN Bandgap Reference SW Oscillator 330kHz FIXED DUTY CYCLE VC FB MIC2141 GND Functional Description Output The maximum output voltage is limited by the voltage capability of the output switch. Output voltages up to 22V can be achieved with a standard boost circuit. Higher output voltages require a flyback configuration. See “Applications Information” for component selection and pre-designed circuits. Overview This MIC2141 is a fixed-duty-cycle, constant-frequency, gated-oscillator, micropower, switch-mode power supply controller. Quiescent current for the MIC2141 is only 70µA in the switch off state, and since a MOSFET output switch is used, additional current needed for switch drive is minimized. Efficiencies above 85% throughout most operating conditions can be realized. Output Voltage Control The internal hysteretic comparator disables the output drive once the output voltage exceeds the nominal by 30mV. The drive is then enabled once the output voltage drops below the nominal by 30mV. The reference level, which actually programs the output voltage, is set by the VC control input. The output is 6 times the control voltage (VC) and the output ripple will be 6 times the comparator hystersis. Therefore, with 10mV of hystersis, there will be ±30mV variation in the output around the nominal value. See the “Typical Characteristics: Control Voltage vs. Output Voltage” for a graph of input-to-output behavior. The common-mode range of the comparator requires that the maximum control voltage (VC) be held to 200mV less than VIN. When programming for a 20V output, a minimum VIN of 3.5V will be required. See the “Typical Characteristics: Gain vs. Output Voltage” for a graph of gain behavior. To achieve 20V output at lower input voltages, the external resistive divider (R1 and R2) shown in Figure 2 can be added. This circuit will increase the control-to-output gain, while limiting the error introduced by the tolerance of the internal resistor feedback network. Regulation Regulation is performed by a hysteretic comparator which regulates the output voltage by gating the internal oscillator. The user applies a programming voltage to the VC pin. (For a fixed or adjustable output regulator, with an internal reference, use the MIC2142.) The output voltage is divided down internally and then compared to the VC, the control input voltage, forcing the output voltage to 6 times the VC. The comparator has hysteresis built into it, which determines the amount of low frequency ripple that will be present on the output. Once the feedback input to the comparator exceeds the control voltage by 10mV, the high-frequency oscillator drive is removed from the output switch. As the feedback input to the comparator returns to the control voltage level, the comparator is reset and the high-frequency oscillator is again gated to the output switch. Typically 10mV of hysteresis seen at the comparator will correspond to 60mV of low-frequency ripple at the output. Applications, which require continuous adjustment of the output voltage, can do so by adjustment of the VC control pin. December 2006 6 M9999-122006 Micrel, Inc. MIC2141 Application Information VOUT VIN(CCM) Pre-designed circuit information is at the end of this section. 3.3V 3.04V 5.0V 4.40V Component Selection Boost Inductor Maximum power is delivered to the load when the oscillator is gated on 100% of the time. Total output power and circuit efficiency must be considered when determining the maximum inductor. The largest inductor possible is preferable in order to minimize the peak current and output ripple. Efficiency can vary from 80% to 90% depending upon input voltage, output voltage, load current, inductor, and output diode. Equation 1 solves for the output current capability for a given inductor value and expected efficiency. Figures 5 through 9; graph estimates for maximum output current, assuming the minimum duty cycle, maximum frequency, and 85% efficiency. To determine the required inductance, find the intersection between the output voltage and current and select the value of the inductor curve just above the intersection. If the efficiency is expected to be other than the 85% used for the graph, Equation 1 can then be used to better determine the maximum output capability. (1) IO(max) = (VIN(min) t ON )2 2L MAX TS × IPK = (3) 10.0V 15.0V 12.4V 16.0V 13.2V 20.0V 16.4V 22.0V 18.0V VIN(ccm) = (VOUT + VFWD) + (1 – D) Table 2 lists common inductors suitable for most applications. Table 6 lists minimum inductor sizes versus input and output voltage. In low-cost, low-peak-current applications, RF-type leaded inductors may sufficient. All inductors listed in Table 4 can be found within the selection of CR32- or LQH4C-series inductors from either Sumida or muRata. 1 VO − VIN(min) eff Manufacturer Series Device Type MuRata LQH1C/C3/C4 surface mount Sumida CR32 surface mount J.W. Miller 78F axial leaded Coilcraft 90 axial leaded Table 2. Inductor Examples Boost Output Diode Speed, forward voltage, and reverse current are very important in selecting the output diode. In the boost configuration, the average diode current is the same as the average load current. (The peak current is the same as the peak inductor current and can be derived from Equation 2 or Figure 10.) Care must be take to make sure that the peak current is evaluated at the maximum input voltage. Diode 75°C VFWD at 100mA 25°C VFWD at 100mA Room Temp. Leakage at 15V 75°C Leakage at 15V Package MBR0530 0.275V 0.325V 2.5µA 90µA SOD123 SMT 1N4148 0.6V (175°C) 0.95V 25nA (20V) 0.2µA (20V) leaded and SMT BAT54 0.4V (85°C) 0.45V 10nA (25V) 1µA (20V) SMT BAT85 0.54V (85°C) 0.56V 0.4µA 2µA (85°C) DO-34 leaded t ON(max) VIN(max) L MIN DCM/CCM Boundary Equation 3 solves for the point at which the inductor current will transition from DCM (discontinuous conduction mode) to CCM (continuous conduction mode). As the input voltage is raised above this level the inductor has a potential for developing a dc component while the oscillator is gated on. Table 1 displays the input points at which the inductor current can possibly operate in the CCM region. Operation in this region can result in a peak current slightly higher than displayed on Table 4. December 2006 7.60V Table 1. DCM/CCM Boundary The peak inductor and switch current can be calculated from Equation 2 or read from the graph in Figure 10. The peak current shown in Figure 10 is derived assuming a maximum duty cycle and a minimum frequency. The selected inductor and diode peak current capability must exceed this value. The peak current seen by the inductor is calculated at the maximum input voltage. A wider input voltage range will result in a higher worst-case peak current in the inductor. This effect can be seen in Table 4 by comparing the difference between the peak current at VIN(min) and VIN(max). (2) 9.0V 12.0V Table 3. Diode Examples 7 M9999-122006 Micrel, Inc. MIC2141 As can be seen in the “Typical Characteristics: Efficiency” graph, the output diode type can have an effect on circuit efficiency. The BAT54- and BAT85series diodes are low-current Shottky diodes available from On Semiconductor and Phillips, respectively. They are suitable for peak repetitive currents of 300mA or less with good reverse current characteristics. For applications that are cost driven, the 1N4148, or equivalent, will provide sufficient switching speed with greater forward drop and reduced cost. Other acceptable diodes are On Semiconductor’s MBR0530 or Vishay’s B0530, although they can have reverse currents that exceed 1mA at very high junction temperatures. Table 3 summarizes some typical performance characteristics of various suitable diodes. IPEAK = Series Type = 0.767µs L MIN 4.8V 13.5µH IPEAK = 272mA Select a BAT54 diode and CR32 inductor. Always check the peak current to insure that it is within the limits specified in the load line shown in Figure 10 for all input and output voltages. Gain Boost Use Figure 2 to increase the voltage gain of the system. The typical gain can easily be increased from the nominal gain of 6 to a value of 8 or 10. Figure 2 shows a gain of 8 so that with 2.5V applied to VC, VOUT will be 20V. Output Capacitor If the availability of tantalum capacitors is limited, ceramic capacitors and inexpensive electrolyics may be necessary. Selection of the capacitor value will depend upon on the peak inductor current and inductor size. MuRata offers the GRM series with up to 10µF at 25V, with a Y5V temperature coefficient, in a 1210 surfacemount package. Low-cost applications can use M-series leaded electrolytic capacitors from Panasonic. In general, ceramic, electrolytic, or tantalum values ranging from 10µF to 47µF can be used for the output capacitor. Manufacturer t ON(max) ⋅ VIN(max) Bootstrap The bootstrap configuration is used to increase the maximum output current for a given input voltage. This is most effective when the input voltage is less than 5V. Output current can typically be tripled by using this technique. See Table 4a. for bootstrap-ready-built component values. L1 33µH VIN +2.7V to +12V C2 10µF 25V Package MuRata GRM ceramic Y5V surface mount VC Vishay 594 tantalum surface mount Return Panasonic M-series Electrolytic leaded CR1 BAT54HT1 VOUT +5V to +15V MIC2141 C4 0.1µF 1 SW FB 3 GND 2 IN 5 VC C1 10µF 25V 4 Return Figure 1. Basic Configuration Table 4. Capacitor Examples Design Example Given a design requirement of 12V output and 1mA load with a minimum input voltage of 2.5V, Equation 1 can be used to calculate to maximum inductance or it can be read from the graph in Figure 4. Once the maximum inductance has been determined, the peak current can be determined using Equation 2 or Figure 9. VOUT = 12V IOUT = 1mA VIN = 4.8V to 2.5V 2 VIN(min) ⋅ t ON(min) L MAX = IO(max) L1 22µH CR1 BAT54HT1 MIC2141 R1 34.8k VIN +2.7V to +12V C2 10µF 25V VC C4 0.1µF 4 5 IN VC SW 3 FB 2 GND 1 VOUT +5V to +20V C1 10µF 25V IFB R2 121k Return ⎛ R1⎞ VOUT = 6VC 1 + ⎟ + I - R1 ⎝ R2 ⎠ FB IFB(typ) = 15m A for VOUT = 15V Return Figure 2. Gain-Boost Configuration L1 4.7µH VIN +2.7V to +4.7V 2 VO − VIN(min) ⋅ 2 ⋅ TS(min) eff VC Return LMAX = 17µH CR2 C4 1N4148 0.1µF C2 10µF 25V CR1 MBR0530 CR3 1N4148 MIC2141 1 IN 5 VC VOUT +12V SW FB 3 GND 2 4 C1 10µF 25V Return Figure 3. Bootstrap Configuration Select 15µH ±10%. December 2006 8 M9999-122006 Micrel, Inc. MIC2141 Inductor Selection Guides Figure 4. Inductor Selection for VIN = 2.5V December 2006 Figure 5. Inductor Selection for VIN = 3.3V 9 M9999-122006 Micrel, Inc. MIC2141 Figure 6. Inductor Selection for VIN = 5V December 2006 Figure 7. Inductor Selection for VIN = 9V 10 M9999-122006 Micrel, Inc. MIC2141 Figure 8. Inductor Selection for VIN = 12V December 2006 11 M9999-122006 Micrel, Inc. MIC2141 Figure 9. Peak Inductor Current vs. Input Voltage December 2006 12 M9999-122006 Micrel, Inc. MIC2141 Pre-designed Circuit Values VIN(min) 2.5V VIN(max) 4.5V VOUT 5.0V 2.5V 11.5V 5V bootstrap 12V 2.5V 2.5V 2.5V 4.7V 4.7V 14V 12V bootstrap 12V bootstrap 15V 2.5V 14V 16V 2.5V 14V 22V 3.0V user for Li-ion battery range 4.5V 5V 3.0V user for Li-ion battery range 3.0V user for Li-ion battery range 3.0V user for Li-ion battery range 8.5V 5V bootstrap 9V 4.7V 9V bootstrap 11.5V 12V 4.7V 12V bootstrap 14V 15V 4.7V 15V bootstrap 14V 22V 3.0V user for Li-ion battery range 3.0V user for Li-ion battery range 3.0V user for Li-ion battery range 3.0V user for Li-ion battery range IOUT(max) 4mA 3mA 2mA 1mA 0.5mA 14.8mA 1mA 0.5mA 0.2mA 3.5mA 4.3mA 0.8mA 0.5mA 0.2mA 0.8mA 0.5mA 0.2mA 0.5mA 0.2mA 0.1mA 10mA 3.6mA 0.8mA 20mA 3mA 1.7mA 0.8mA 8mA L1 15µH 18µH 27µH 56µH 120µH 3.9µH 15µH 33µH 82µH 4.7µH 3.9µH 15µH 27µH 68µH 15µH 22µH 56µH 15µH 39µH 82µH 12µH 27µH 120µH 4.7µH 12µH 22µH 47µH 4.7µH CR1 BAT54 BAT54 BAT54 BAT54 BAT54 MBR0530 MBR0530 BAT54 BAT54 MBR0530 MBR0530 MBR0530 MBR0530 BAT54 MBR0530 MBR0530 BAT54 MBR0530 BAT54 BAT54 BAT54 BAT54 BAT54 MBR0530 MBR0530 MBR0530 MBR0530 MBR0530 IPEAK (VIN = VOUT – 0.5V) or 14V 230mA 192mA 128mA 62mA 29mA 890mA 588mA 267mA 108mA 750mA 900mA 741mA 412mA 163mA 710mA 456mA 190mA 590mA 247mA 130mA 288mA 128mA 29mA 730mA 652mA 296mA 139mA 750mA 2.1mA 1.7mA 1mA 0.45mA 5.4mA 12µH 15µH 27µH 56µH 4.7µH MBR0530 MBR0530 MBR0530 BAT54 MBR0530 882mA 588mA 327mA 157mA 750mA 190mA 156mA 85mA 40mA 450mA 1.6mA 0.87mA 0.41mA 4mA 12µH 22µH 47µH 4.7µH MBR0530 MBR0530 BAT54 MBR0530 926mA 505mA 237mA 750mA 190mA 103mA 49mA 450mA 1mA 0.8mA 0.46mA 0.2mA 10µH 15µH 27µH 68µH MBR0530 MBR0530 MBR0530 BAT54 1071mA 714mA 400mA 157mA 190mA 152mA 85mA 3.3mA IPEAK (VIN = VIN(MIN)) 128mA 106mA 71mA 34mA 16mA 500mA 128mA 58mA 23mA 500mA 500mA 128mA 71mA 28mA 128mA 87mA 34mA 128mA 49mA 23mA 190mA 85mA 19mA 450mA 190mA 103mA 49mA 450mA Table 4a. Typical Configurations for Wide-Range Inputs—2.5V to 3.0V Minimum Input December 2006 13 M9999-122006 Micrel, Inc. MIC2141 VIN(min) 5.0V VIN(max) 8.5V VOUT 9V 5.0V 11.5V 12V 5.0V 14V 15V 5.0V 14V 16V 5.0V 14V 22V 9.0V 11.5V 12V 9.0V 14V 15V 9.0V 14V 20V 9.0V 14V 22V 12V 14V 15V 12V 14V 20V 12V 21.5V 22V IOUT(max) 17mA 15mA 10mA 5mA 1mA 10mA 5mA 2mA 1mA 7mA 5mA 2mA 1mA 2.5mA 1mA 0.5mA 1.7mA 1.0mA 0.5mA 0.1mA 33mA 20mA 10mA 5mA 1mA 20mA 10mA 5mA 2mA 1mA 4.5mA 2mA 1mA 4mA 2mA 1mA 45mA 20mA 10mA 5mA 1.7mA 8mA 5mA 2mA 1mA 7mA 5mA 2mA 1mA L1 8.2µH 10µH 12µH 27µH 120µH 8.2µH 18µH 39µH 82µH 8.2µH 12µH 27µH 56µH 22µH 56µH 120µH 22µH 39µH 82µH 180µH 15µH 22µH 47µH 100µH 470µH 15µH 27µH 56µH 150µH 270µH 39µH 68µH 150µH 39µH 68µH 150µH 18µH 39µH 82µH 150µH 470µH 47µH 68µH 120µH 390µH 47µH 68µH 150µH 220µH CR1 MBR0530 MBR0530 MBR0530 BAT54 BAT54 MBR0530 MBR0530 BAT54 BAT54 MBR0530 MBR0530 MBR0530 BAT54 MBR0530 BAT54 BAT54 MBR0530 BAT54 BAT54 BAT54 MBR0530 MBR0530 BAT54 BAT54 BAT54 MBR0530 MBR0530 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 MBR0530 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 BAT54 IPEAK (VIN = VOUT – 0.5V) or 14V 795mA 652mA 643mA 241mA 54mA 1075mA 490mA 226mA 108mA 1356mA 926mA 412mA 199mA 986mA 190mA 90mA 486mA 274mA 130mA 60mA 588mA 401mA 188mA 88mA 19mA 741mA 412mA 199mA 74mA 41mA 215mA 131mA 72mA 275mA 157mA 72mA 618mA 285mA 136mA 74mA 24mA 230mA 158mA 90mA 27mA 228mA 157mA 69mA 47mA IPEAK (VIN = VIN(MIN)) 467mA 838mA 319mA 142mA 32mA 467mA 213mA 98mA 47mA 467mA 319mA 142mA 68mA 174mA 68mA 32mA 174mA 98mA 47mA 21mA 460mA 256mA 123mA 46mA 26mA 460mA 256mA 123mA 46mA 26mA 177mA 84mA 46mA 177mA 101mA 46mA 511mA 236mA 112mA 61mA 20mA 196mA 135mA 77mA 24mA 196mA 135mA 61mA 42mA Table 4b. Typical Configurations for Wide-Range Inputs—5V to 15V Minimum Input December 2006 14 M9999-122006 Micrel, Inc. MIC2141 VIN VOUT IOUT L1 CR1 3.3V±5% 5V 9V 12V 15V 20V 9V 12V 15V 20V 15V 20V 13mA 5mA 3mA 2.3mA 1.7mA 17mA 10.4mA 7.5mA 2.2mA 44mA 8.3mA 10µH 10µH 10µH 10µH 10µH 8.2µH 8.2µH 8.2µH 22µH 18µH 47µH BAT54 BAT54 BAT54 BAT54 BAT54 MBR0530 MBR0530 MBR0530 MBR0530 MBR0530 BAT54 5V±5% 12V±5% IPEAK (typical) 253mA 253mA 253mA 253mA 253mA 467mA 467mA 467mA 174mA 511mA 196mA Table 5. Typical Maximum Power Configurations for Regulated Inputs VIN 2.5V 3.0V 3.3V 3.5V 4.0V 4.5V 5.0V 6.0V 7.0V 8.0V 9.0V 10V 11V 12V 13V 14V 15V 16V Output Voltage 16V to 22V 4.5V to 15V 15µH 15µH 12µH 12µH 10µH 10µH 8.2µH 8.2µH 27µH 6.8µH 27µH 6.8µH 22µH 8.2µH 27µH 10µH 27µH 10µH 33µH 12µH 39µH 15µH 39µH 15µH 47µH 18µH 47µH 18µH 56µH 22µH 56µH 22µH 56µH 27µH 68µH 27µH Table 6. Minimum Inductance Manufacturer MuRata Sumida Coilcraft J.W. Miller Micrel Vishay Panasonic Web Address www.murata.com www.sumida.com www.coilcraft.com www.jwmiller.com www.micre.com www.vishay.com www.panasonic.com Table 7. Component Supplier Websites December 2006 15 M9999-122006 Micrel, Inc. MIC2141 Package Information 5-Pin SOT23 (M) 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. © 2000 Micrel, Incorporated. December 2006 16 M9999-122006