MIC2196 400kHz SO-8 Boost Control IC General Description Features Micrel’s MIC2196 is a high efficiency PWM boost control IC housed in a SO-8 package. The MIC2196 is optimized for low input voltage applications. With its wide input voltage range of 2.9V to 14V, the MIC2196 can be used to efficiently boost voltages in 3.3V, 5V, and 12V systems, as well as 1- or 2-cell Li Ion battery powered applications. Its powerful 2Ω output driver allows the MIC2196 to drive large external MOSFETs. The MIC2196 is ideal for space-sensitive applications. The device is housed in the space-saving SO-8 package, whose low pin-count minimizes external components. Its 400kHz PWM operation allows a small inductor and small output capacitors to be used. The MIC2196 can implement all ceramic capacitor solutions. Efficiencies over 90% are achievable over a wide range of load conditions with the MIC2196’s PWM boost control scheme. Its fixed frequency PWM architecture also makes the MIC2196 is ideal for noise-sensitive telecommunications applications. MIC2196 features a low current shutdown mode of 1μA and programmable undervoltage lockout. The MIC2196 is available in an 8-pin SOIC package with a junction temperature range from –40°C to +125°C. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • • • • • • • • • • • 2.9V to 14V input voltage range >90% efficiency 2Ω output driver 400kHz oscillator frequency PWM current mode control 0.5μA micro power shutdown Programmable UVLO Front edge blanking Cycle-by-cycle current limiting Frequency foldback short-circuit protection 8-pin SOIC package Applications • • • • • • • • • Step-up conversion in telecom/datacom systems SLIC power supplies SEPIC power supplies Low input voltage flyback and forward converters Wireless modems Cable modems ADSL line cards Base stations 1-and 2-cell Li Ion battery operated equipment _________________________________________________________________________________________________________ Typical Application VIN 5V 4.7µH 47µF 16V MIC2196BM Si4884 (x2) B530 VOUT 12V, 3A MIC2196 5V to 12V Efficiency 100 10k 1µF COMP 10k 1.15k FB 10nF Adjustable Output Boost Converter 120µF 20V (x3) 95 90 EFFICIENCY (%) VIN OUTN EN/ CS UVLO GND VDD 85 80 75 70 65 60 55 VIN = 5V 50 0 0.5 1 1.5 2 2.5 3 3.5 4 OUTPUT CURRENT (A) Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com September 2008 M9999-092908 Micrel, Inc. MIC2196 Ordering Information Part Number Voltage Frequency Temperature Range Package Lead Finish MIC2196BM Adj. 400kHz –40°C to +125°C 8-Pin SOIC Standard MIC2196YM Adj. 400kHz –40°C to +125°C 8-Pin SOIC Pb-Free Pin Configuration COMP 1 8 VIN FB 2 7 OUTN EN/UVLO 3 6 GND CS 4 5 VDD 8-Pin SOIC (M) Pin Description Pin Number Pin Name 1 COMP 2 FB 3 EN/UVLO Enable/Undervoltage Lockout (input): A low level on this pin will power down the device, reducing the quiescent current to under 0.5μA. This pin has two separate thresholds, below 1.5V the output switching is disabled, and below 0.9V the device is forced into a complete micropower shutdown. The 1.5V threshold functions as an accurate undervoltage lockout (UVLO) with 100mV hysteresis. 4 CS The (+) input to the current limit comparator. A built in offset of 100mV between CS and GND in conjunction with the current sense resistor sets the current limit threshold level. This is also the (+) input to the current amplifier. 5 VDD 3V internal linear-regulator output. VDD is also the supply voltage bus for the chip. Bypass to GND with 1μF. 6 GND Ground. 7 OUTN 8 VIN September 2008 Pin Function Compensation (Output): Internal error amplifier output. Connect to a capacitor or series RC network to compensate the regulator’s control loop. Feedback (Input): Regulates FB to 1.245V. High current drive for N-Channel MOSFET. Voltage swing is from ground to VIN. RON is typically 3Ω @ 5VIN. Input voltage to the control IC. This pin also supplies power to the gate drive circuit. 2 M9999-092908 Micrel, Inc. MIC2196 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) .......................................................15V Digital Supply Voltage (VDD).............................................7V Comp Pin Voltage (VCOMP) .............................. –0.3V to +3V Feedback Pin Voltage (VFB) ............................ –0.3V to +3V Enable Pin Voltage (VEN/UVLO) ....................... –0.3V to +15V Current Sense Voltage (VCS)........................... –0.3V to +1V Power Dissipation (PD) ....................... 285mW @ TA = 85°C Ambient Storage Temperature (Ts) ...........–65°C to +150°C ESD Rating(3) .................................................................. 2kV Supply Voltage (VIN)...................................... +2.9V to +14V Junction Temperature .........................–40°C ≤ TJ ≤ +125°C Package Thermal Resistance SOIC-8 (θJA).....................................................140°C/W Electrical Characteristics VIN = 5V; VOUT = 12V; TA = 25°C. Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted. Parameter Condition Min Typ Max Units (±1%) 1.233 1.245 1.258 V (±2%) 1.220 1.245 1.270 V Regulation Feedback Voltage Reference Feedback Bias Current Output Voltage Line Regulation 3V ≤ VIN ≤ 9V Output Voltage Load Regulation 0mV ≤ VCS ≤ 75mV Output Voltage Total Regulation 3V ≤ VIN ≤ 9V; 0mV ≤ VCS ≤ 75mV (±3%) 50 nA +0.08 %/V -1.2 % 1.208 1.282 V 1 2 mA 0.5 5 µA 3.0 3.18 V Input & VDD Supply VIN Input Current (IQ) (excluding external MOSFET gate current) Shutdown Quiescent Current VEN/UVLO = 0V Digital Supply Voltage (VDD) IL = 0 Digital Supply Load Regulation IL = 0 to 5mA 0.1 V Undervoltage Lockout VDD upper threshold (turn on threshold) 2.65 V 100 mV 2.82 UVLO Hysteresis Enable/UVLO Enable Input Threshold 0.6 0.9 1.2 V UVLO Threshold 1.4 1.5 1.6 V 0.2 5 µA 110 130 mV Enable Input Current VEN/UVLO = 5V Current Limit Current Limit Threshold Voltage (Voltage on CS to trip current limit) 90 Error Amplifier Error Amplifier Gain 20 V/V 3.7 V/V Current Amplifier Current Amplifier Gain Oscillator Section Oscillator Frequency (fO) Maximum Duty Cycle 360 400 440 kHz VFB = 1.0V 85 % Minimum On Time VFB = 1.5V 165 ns Frequency Foldback Threshold Measured on FB 0.3 V 90 kHz Frequency Foldback Frequency September 2008 3 M9999-092908 Micrel, Inc. Parameter MIC2196 Condition Min Typ Max Units Gate Drivers Rise/Fall Time Output Driver Impedance CL = 3300pF 25 ns Source, VIN = 12V 2 6 Ω Sink, VIN = 12V 2 6 Ω Source, VIN = 5V 3 7 Ω Sink, VIN = 5V 3 7 Ω Notes: 1. Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(Max), the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. 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. September 2008 4 M9999-092908 Micrel, Inc. MIC2196 Typical Characteristics 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.0 0 Standby 2 4 6 8 10 12 14 INPUT VOLTAGE (V) V 3.00 1.2 1.0 0.8 2.95 2.85 0.2 0 -60 -40 -20 0 20 40 60 80 100120 TEMPERATURE (°C) 3.5 VIN = 5V 3.4 3.3 3.2 3.1 3 2.9 2.8 2.7 2.6 2.5 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) VIN = 3.3V 0.2 0.4 0.6 0.8 1.0 LOAD CURRENT (mA) 1.2 Reference Voltage vs. Temperature 1.27 1.26 1.25 1.24 1.23 1.22 1.21 130.0 THRESHOLD (mV) 125.0 120.0 115.0 110.0 105.0 100.0 95.0 90.0 0 2 4 6 8 10 12 14 INPUT VOLTAGE (V) September 2008 1.244 1.243 1.242 1.241 1.24 1.239 1.238 0 2 4 6 8 10 12 14 16 INPUT VOLTAGE (VINA) Frequency vs. Temperature 450 440 -0.5 -1.0 -1.5 -2.0 -2.5 0 CURRENT LIMIT THRESHOLD (mV) 1.20 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Overcurrent Threshold vs. Input Voltage 1.245 0.5 0.0 4 6 8 10 12 14 16 INPUT VOLTAGE (V) 1.246 Switching Frequency vs. Input Voltage FREQUENCY VARIATION (%) REFERENCE VOLTAGE (V) VIN = 5V 1.29 1.28 2 Reference Voltage vs. Input Voltage FREQUENCY (kHz) VIN = 12V 1.30 2.80 0 VDD vs. Temperature VDD (V) VDD (V) 2.92 0 2.90 0.6 0.4 VIN = 5V 2.97 2.96 2.95 2.94 2.93 VDD vs. Input Voltage 3.05 = 5V 1.6 1.4 VDD vs. Load 3.02 3.01 3.00 2.99 2.98 IN REFERENCE VOLTAGE (V) 0.5 2.0 1.8 VDD (V) Switching Quiescent Current vs. Temprerature VIN = 5V 430 420 410 400 390 380 370 360 2 4 6 8 10 12 14 INPUT VOLTAGE (V) 350 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Current Limit vs. Temperature 120 VIN = 5V 115 110 105 100 95 90 85 80 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 5 Enable Pin vs. Input Voltage 200 ENABLE PIN CURRENT (µA) 4.5 QUIESCENT CURRENT (mA) QUIESCENT CURRENT (mA) 5.0 Quiescent Current vs. Supply Voltage 150 100 50 0 -50 0 2 4 6 8 10 12 14 INPUT VOLTAGE (V) M9999-092908 Micrel, Inc. MIC2196 Functional Diagram VIN CIN CDECOUP L1 VIN 8 VREF Bias EN/UVLO 3 VDD D1 VOUT On Control COUT fs/4 OUTN 7 Reset Overcurrent Reset Osc PWM Comparator 0.11V Corrective Ramp Overcurrent Comparator CS 4 Gain = 3.7 RSENSE Error Amplifier VREF COMP gm = 0.0002 Gain = 20 2 100k 0.3V fs/4 R1 Vfb 2 VDD 5 Frequency Foldback VDD R2 GND GND 6 Figure 1. MIC2196 Block Diagram September 2008 6 M9999-092908 Micrel, Inc. MIC2196 Functional Description The MIC2196 is a BiCMOS, switched-mode multitopology controller. It will operate most low-side drive topologies including boost, SEPIC, flyback and forward. The controller has a low impedance driver capable of switching large N-Channel MOSFETs. It features multiple frequency and duty cycle settings. Current mode control is used to achieve superior transient line and load regulation. An internal corrective ramp provides slope compensation for stable operation above a 50% duty cycle. The controller is optimized for high efficiency, high-performance DC-DC converter applications. Figure 1 shows a block diagram of the MIC2196 configured as a PWM boost converter. The switching cycle starts when OUTN goes high and turns on the low-side, N-Channel MOSFET, Q1. The VGS of the MOSFET is equal to VIN. This forces current to ramp up in the inductor. The inductor current flows through the current sense resistor, RSENSE. The voltage across the resistor is amplified and combined with an internal ramp for stability. This signal is compared with the error voltage signal from the error amplifier. When the current signal equals the error voltage signal, the low-side MOSFET is turned off. The inductor current then flows through the diode, D1, to the output. The MOSFET remains off until the beginning of the next switching cycle. The description of the MIC2196 controller is broken down into several functions: • Control Loop • PWM Operation • Current Limit • MOSFET gate drive • Reference, enable & UVLO • Oscillator Figure 2. PWM Mode Waveforms The MIC2196 uses current mode control to improve output regulation and simplify compensation of the control loop. Current mode control senses both the output voltage (outer loop) and the inductor current (inner loop). It uses the inductor current and output voltage to determine the duty cycle (D) of the buck converter. Sampling the inductor current effectively removes the inductor from the control loop, which simplifies compensation. A simplified current mode control diagram is shown in Figure 3. I_inductor VIN Voltage Divider I_inductor Gate Driver I_inductor Control Loop The MIC2196 operates in PWM (pulse-width modulated) mode. VREF I_inductor VCOMP PWM Operation Figure 2 shows typical waveforms for PWM mode of operation. The gate drive signal turns on the external MOSFET which allows the inductor current to ramp up. When the MOSFET turns off, the inductor forces the MOSFET drain voltage to rise until the boost diode turns on and the voltage is clamped at approximately the output voltage. September 2008 Gate Drive at OUTN TON TPER Figure 3. PWM Control Loop 7 M9999-092908 Micrel, Inc. MIC2196 A block diagram of the MIC2196 PWM current mode control loop is shown in Figure 1. The inductor current is sensed by measuring the voltage across a resistor, RSENSE. The current sense amplifier buffers and amplifies this signal. A ramp is added to this signal to provide slope compensation, which is required in current mode control to prevent unstable operation at duty cycles greater than 50%. A transconductance amplifier is used as an error amplifier, which compares an attenuated output voltage with a reference voltage. The output of the error amplifier is compared to the current sense waveform in the PWM block. When the current signal rises above the error voltage, the comparator turns off the low-side drive. The error signal is brought out to the COMP pin (pin 1) to provide access to the output of the error amplifier. This allows the use of external components to stabilize the voltage loop. VIN is the minimum input voltage L is the value of the boost inductor fs is the switching frequency VO is the output voltage Maximum Peak Current in Discontinuous Mode: The peak inductor current is: where: IO is the maximum output current VO is the output voltage VIN is the minimum input voltage L is the value of the boost inductor fs is the switching frequency η is the efficiency of the boost converter The maximum value of current sense resistor is: Current Sensing and Overcurrent Protection The inductor current is sensed during the switch on time by a current sense resistor located between the source of the MOSFET and ground (RSENSE in Figure 1). Exceeding the current limit threshold will immediately terminate the gate drive of the N-Channel MOSFET, Q1. This forces the Q1 to operate at a reduced duty cycle, which lowers the output voltage. In a boost converter, the overcurrent limit will not protect the power supply or load during a severe overcurrent condition or short circuit condition. If the output is shortcircuited to ground, current will flow from the input, through the inductor and output diode to ground. Only the impedance of the source and components limits the current. The mode of operation (continuous or discontinuous), the minimum input voltage, maximum output power and the minimum value of the current limit threshold determine the value of the current sense resistor. Discontinuous mode is where all the energy in the inductor is delivered to the output at each switching cycle. Continuous mode of operation occurs when current always flows in the inductor, during both the lowside MOSFET on and off times. The equations below will help to determine the current sense resistor value for each operating mode. The critical value of output current in a boost converter is calculated below. The operating mode is discontinuous if the output current is below this value and is continuous if above this value. R SENSE = V is the minimum current sense threshold of the CS pin. Maximum Peak Current in Continuous Mode: The peak inductor current is equal to the average inductor current plus one half of the peak to peak inductor current. The peak inductor current is: IIND(pk) = IIND(ave) + IIND(pk) = 1 × IIND(pp) 2 VO × IO VL × (VO − VIN × η) + VIN × η 2 × VO × fs × L where: IO is the maximum output current VO is the output voltage VIN is the minimum input voltage L is the value of the boost inductor fs is the switching frequency η is the efficiency of the boost converter VL is the voltage across the inductor VL may be approximated as VIN for higher input voltage. However, the voltage drop across the inductor winding resistance and low-side MOSFET on-resistance must be accounted for at the lower input voltages that the MIC2196 operates at: VIN × (VO − VIN ) × η 2 × fs × L × VO VSENSE IIND(pk) where: 2 ICRIT = 2 × IO × (VO − η × VIN ) L × fs IIND(pk) = 2 where: η is the efficiency of the boost converter September 2008 8 M9999-092908 Micrel, Inc. MIC2196 VL = VIN − VO × IO × (R WINDING + R DSON ) VIN × η where: Q_gate is the total gate charge of the external MOSFET The graph in Figure 4 shows the total gate charge which can be driven by the MIC2196 over the input voltage range. Higher gate charge will slow down the turn-on and turn-off times of the MOSFET, which increases switching losses. where: RWINDING is the winding resistance of the inductor RDSON is the on resistance of the low side switching MOSFET The maximum value of current sense resistor is: VSENSE IIND(pk) Max. Gate Charge MAXIMUM GATE CHARGE (nC) R SENSE = where: VSENSE is the minimum current sense threshold of the CS pin. The current sense pin, CS, is noise sensitive due to the low signal level. The current sense voltage measurement is referenced to the signal ground pin of the MIC2196. The current sense resistor ground should be located close to the IC ground. Make sure there are no high currents flowing in this trace. The PCB trace between the high side of the current sense resistor and the CS pin should also be short and routed close to the ground connection. The input to the internal current sense amplifier has a 30ns dead time at the beginning of each switching cycle. This dead time prevents leading edge current spikes from prematurely terminating the switching cycle. A small RC filter between the current sense pin and current sense resistor may help to attenuate larger switching spikes or high frequency switching noise. Adding the filter slows down the current sense signal, which has the effect of slightly raising the overcurrent limit threshold. 200 150 100 50 0 0 2 4 6 8 10 12 14 INPUT VOLTAGE (V) Figure 4. MIC2196 Frequency vs. Gate Charge External Schottky Diode In a boost converter topology, the boost diode, D1 must be rated to handle the peak and average current. The average current through the diode is equal to the average output current of the boost converter. The peak current is calculated in the current limit section of this specification. For the MIC2196, Schottky diodes are recommended when they can be used. They have a lower forward voltage drop than ultra-fast rectifier diodes, which lowers power dissipation and improves efficiency. They also do not have a recovery time mechanism, which results in less ringing and noise when the diode turns off. If the output voltage of the circuit prevents the use of a Schottky diode, then only ultra-fast recovery diodes should be used. Slower diodes will dissipate more power in both the MOSFET and the diode. The will also cause excessive ringing and noise when the diode turns off. MOSFET Gate Drive The MIC2196 converter drives a low-side N-Channel MOSFET. The driver for the OUTN pin has a 2Ω typical source and sink impedance. The VIN pin is the supply pin for the gate drive circuit. The maximum supply voltage to the VIN pin is 14V. MOSFET Selection In a boost converter, the VDS of the MOSFET is approximately equal to the output voltage. The maximum VDS rating of the MOSFET must be high enough to allow for ringing and spikes in addition to the output voltage. The VIN pin supplies the N-Channel gate drive voltage. The VGS threshold voltage of the N-channel MOSFET must be low enough to operate at the minimum VIN voltage to guarantee the boost converter will start up. The maximum amount of MOSFET gate charge that can be driven is limited by the power dissipation in the MIC2196. The power dissipated by the gate drive circuitry is calculated below: Reference, Enable and UVLO Circuits The output drivers are enabled when the following conditions are satisfied: • The VDD voltage (pin 5) is greater than its undervoltage threshold. • The voltage on the enable pin is greater than the enable UVLO threshold. The internal bias circuitry generates a 1.245V bandgap reference for the voltage error amplifier and a 3V VDD voltage for the internal supply bus. The VDD pin must be decoupled to ground with a 1μF ceramic capacitor. P_gate_dri ve = Q_gate × VIN × fs September 2008 250 9 M9999-092908 Micrel, Inc. MIC2196 The enable pin (pin 3) has two threshold levels, allowing the MIC2196 to shut down in a micro-current mode, or turn-off output switching in standby mode. Below 0.9V, the device is forced into a micro power shutdown. If the enable pin is between 0.9V and 1.5V the output gate drive is disabled but the internal circuitry is powered on and the soft start pin voltage is forced low. There is typically 135mV of hysteresis below the 1.5V threshold to insure the part does not oscillate on and off due to ripple voltage on the input. Raising the enable voltage above the UVLO threshold of 1.5V enables the output drivers and allows the soft start capacitor to charge. The enable pin may be pulled up to VINA. Decoupling Capacitor Selection A 1μF decoupling capacitor is used to stabilize the internal regulator and minimize noise on the VDD pin. Placement of this capacitor is critical to the proper operation of the MIC2196. It must be next to the VDD and signal ground pins and routed with wide etch. The capacitor should be a good quality ceramic. Incorrect placement of the VDD decoupling capacitor will cause jitter and/or oscillations in the switching waveform as well as variations in the overcurrent limit. A minimum 1μF ceramic capacitor is required to decouple the VIN. The capacitor should be placed near the IC and connected directly between pins 8 (VCC) and 6 (GND). For VIN greater than 8V, use a 4.7μF or a 10μF ceramic capacitor to decouple the VDD pin. Oscillator and Sync The internal oscillator is self-contained and requires no external components. The maximum duty cycle of the MIC2196 is 85%. Minimum duty cycle becomes important in a boost converter as the input voltage approaches the output voltage. At lower duty cycles, the input voltage can be closer to the output voltage without the output rising out of regulation. Minimum duty cycle is typically 7%. A frequency foldback mode is enabled if the voltage on the feedback pin (pin 2) is less than 0.3V. In frequency foldback the oscillator frequency is reduced by approximately a factor of 4. Efficiency Calculation and Considerations Efficiency is the ratio of output power to input power. The difference is dissipated as heat in the boost converter. The significant contributors at light output loads are: • • Core losses in the inductor. To maximize efficiency at light loads: • Voltage Setting Components The MIC2196 requires two resistors to set the output voltage as shown in Figure 5. Use a ferrite material for the inductor core, which has less core loss than an MPP or iron power core. The significant contributors to power loss at higher output loads are (in approximate order of magnitude): R1 Pin 6 R2 VREF 1.245V • Resistive on-time losses in the MOSFET • Switching transition losses in the MOSFET • Inductor resistive losses • Current sense resistor losses • Output capacitor resistive losses (due to the capacitor’s ESR) To minimize power loss under heavy loads: Figure 5. Voltage Setting Components The output voltage is determined by the equation below: R1 R2 Where: VREF for the MIC2196 is nominally 1.245V. Lower values of resistance are preferred to prevent noise from appearing on the VFB pin. A typically recommended value for R1 is 10K. • Use logic level, low on resistance MOSFETs. Multiplying the gate charge by the on-resistance gives a figure of merit, providing a good balance between switching and resistive power dissipation. • Slow transition times and oscillations on the voltage and current waveforms dissipate more power during the turn-on and turn-off of the low side MOSFET. A clean layout will minimize parasitic inductance and capacitance in the gate drive and high current paths. This will allow the VO = VREF × 1 + September 2008 Use a low gate charge MOSFET or use the smallest MOSFET, which is still adequate for the maximum output current. • MIC2196 Voltage Amplifier The VIN pin supply current which includes the current required to switch the external MOSFETs. 10 M9999-092908 Micrel, Inc. MIC2196 fastest transition times and waveforms without oscillations. Low gate charge MOSFETs will switch faster than those with higher gate charge specifications. • For the same size inductor, a lower value will have fewer turns and therefore, lower winding resistance. However, using too small of a value will increase the inductor current and therefore require more output capacitors to filter the output ripple. September 2008 11 • Lowering the current sense resistor value will decrease the power dissipated in the resistor. However, it will also increase the overcurrent limit and may require larger MOSFETs and inductor components to handle the higher currents. • Use low ESR output capacitors to minimize the power dissipated in the capacitor’s ESR. M9999-092908 Micrel, Inc. MIC2196 Package Information 8-Pin SOIC (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. © 2004 Micrel, Incorporated. September 2008 12 M9999-092908