MIC2807 RF PA Power Management IC 2MHz, 600mA DC/DC w/DAC Input and Bypass Switch, Dual Low Noise 200mA/30mA LDO Regulators General Description Features The MIC2807 integrates a high performance 600mA DC/DC converter intended for powering a power amplifier (PA) in a mobile phone with dual low noise low dropout (LDO) regulators for the rest of the RF section. Optimized for low noise performance, the MIC2807 improves efficiency in the handset without compromising quality. The MIC2807 has a 2MHz, constant frequency pulse width modulated (PWM) DC/DC converter designed for low noise operation and high efficiency. The output voltage (VOUT) is variable from 0.3V to the input voltage (VIN), adjustable from 0.3V to 3.6V through a DAC input when VIN > VOUT. The converter will work in a 100% duty cycle mode to offer maximum power and efficiency in the application. In addition to 100% duty cycle, the DC/DC converter has a bypass mode of operation where the input voltage node (PVIN pin) is shorted to the output voltage node (OUT pin) through a 95mΩ switch. The integrated dual low noise low dropout regulators are optimized for high PSRR capability and fast turn-on times. The constant frequency DC/DC converter along with dual low noise LDO regulators enables a very quiet and efficient solution for mobile applications. The MIC2807 is a µCap design, operating with small ceramic output capacitors and inductors for stability, reducing required board space and component cost and it is available in the tiny 2.5mm x 2.8mm MLF® package. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • • • • • 2.7V to 5.5V input voltage range Stable with ceramic output capacitors Tiny 17-pin 2.5mm x 2.8mm MLF® Package Thermal shutdown protection Current limit protection RF PA Power Supply DC/DC Converter • Adjustable output power supply – DAC controlled – VOUT = VDAC x 3 • Bypass mode operation – Internal 95mΩ switch between PVIN and OUT pins – VDAC > 1.2V • Up to 600mA output current in PWM mode • 100% duty cycle operation for maximum efficiency • Tiny 4.7µH, 1µF output inductor and capacitor • Low-noise 2MHz PWM operation • >90% efficiency Dual Low Noise Low Dropout Regulators • High accuracy – ±2% over temperature • High PSRR – greater than 70dB • Very low output noise – 32µVrms • LDO1 – 200mA output current capability • LDO2 – 30mA output current capability Applications • • • • • CDMA2000 mobile phones UMTS/WCDMA mobile phones Wibro modules WiFi modules Power amplifier modules (PAMs) with linear PAs Typical Application 4.5 DC/DC Output Voltage vs. DAC Voltage VIN = 4.2V 4.0 IOUT = 100mA 3 x V D AC 2.5 T O U V 1.5 = 2.0 Bypass Mode 3.5 3.0 1.0 0.5 CDMA2000/WCDMA RF Power Supply Circuit 0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 DAC VOLTAGE (V) 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 February 2008 M9999-022008-B Micrel, Inc. MIC2807 Ordering Information Part Number Marking Code* MIC2807-JJYML MIC2807-MMYML MIC2807-NNYML MIC2807-OOYML YJJJ YJMM YJNN YJOO LDO1/LDO2 Voltage** 2.5V/2.5V 2.8V/2.8V 2.85V/2.85V 2.9V/2.9V Junction Temp. Range –40°C to +125°C –40°C to +125°C –40°C to +125°C –40°C to +125°C Package Lead Finish 17-Pin 2.5mm x 2.8mm MLF ® Pb-Free 17-Pin 2.5mm x 2.8mm MLF ® Pb-Free 17-Pin 2.5mm x 2.8mm MLF ® Pb-Free 17-Pin 2.5mm x 2.8mm MLF ® Pb-Free Notes: MLF® is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. * Over bar ( ) symbol may not be to scale. ** Other voltage options available. Please contact Micrel for details. Pin Configuration 17-Pin 2.5mm x 2.8mm MLF® (ML) (Top View) February 2008 2 M9999-022008-B Micrel, Inc. MIC2807 Pin Description Pin Number Pin Name 1 DAC DAC Control Input (Analog Voltage Input). Provides control of output voltage of DC/DC converter. The output voltage is 3x’s the DAC voltage (Ex. 0.5VDAC = 1.5VOUT) when VIN > VOUT. Bypass mode is enabled when the DAC voltage exceeds 1.2V or VIN ≤ VOUT. VOUT = VDAC x 3. 2 BYP Filter capacitor for LDO1 and LDO2 internal voltage reference, connect capacitor to ground. 3 AGND 4 EN2 Enables the LDO2 regulator. 5 VIN LDO1 and LDO2 Supply Voltage. Must be connected to PIN 15. 6 LDO1 Output of the LDO1. 7 LDO2 Output of the LDO2. 8, 9 OUT Drain of internal bypass switch, also serves as feedback for the internal regulator. 10 PGND 11 SW 12 PVIN Supply Voltage: Requires bypass capacitor to ground. 13 EN1 Enables LDO1 Regulator. 14 EN 15 AVIN 16, 17 NC February 2008 Pin Function Signal ground of chip. Power ground. Switch: Internal power MOSFET output switches of DC/DC converter. Enables the DC/DC Converter. Supply voltage for DC/DC converter control circuitry and reference voltage circuit. Must be connected to PIN 5. No Connect. 3 M9999-022008-B Micrel, Inc. MIC2807 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (PVIN, AVIN, VIN) ............................ 0V to 6V Output Switch Voltage (VSW). ...........................................6V DAC Input Voltage (VDAC)....................................... 0V to VIN Logic Input Voltage (VEN, VEN1, VEN2) ..................... 0V to VIN Power Dissipation(3)...................................Internally Limited Storage Temperature (Ts) .........................–65°C to +150°C ESD Rating(4) ................................................................ ±2kV Supply Voltage (PVIN, AVIN, VIN) ...................... 2.7V to 5.5V Output Voltage (VOUT) ............................................ 0V to VIN Enable Voltage (VEN, VEN1, VEN2)............................ 0V to VIN DAC Input Voltage (VDAC).................................... 0.1V to VIN Junction Temperature (TJ) ........................ –40°C to +125°C Thermal Resistance 2.5x2.8mm MLF-17 (θJA) ...................................70°C/W Electrical Characteristics(5) DC/DC Converter VIN = PVIN = AVIN = VEN = 3.6V; VDAC = 0.6V; VEN1 = VEN2 = 0V; L = 4.7µH; COUT = 1µF; TA = 25°C, bold values indicate –40°C< TJ < +125°C, unless noted. LDO1/LDO2 VIN = VEN1 = VEN2 = 3.6V; COUTLDO1 = 2.2µF; VEN = 0V; COUTLDO2 = 1µF; IOUT = 100µA; TA = 25°C, bold values indicate –40°C< TJ < +125°C, unless noted. Parameter Condition Min Typ Max Units 5.5 V MIC2807 Supply Voltage Range Total Quiescent Current Enable Pin Threshold 2.7 VEN = VEN1 = VEN2 = 3.6V VDAC = 0.6V (DC/DC: not switching) Logic Low Logic High 480 0.4 1.3 Enable Pin Hysteresis Enable Pin Input Current Under-Voltage Lockout Threshold UVLO Hysteresis Shutdown Temperature 30 0.01 2.6 (turn-on) Shutdown Temperature Hysteresis Total Shutdown Current VEN = VEN1 = VEN2 = 0V DC/DC Converter [VEN1 = VEN2 = 0V] Output Voltage Line Regulation Output Voltage Load Regulation Switch On-Resistance 85 160 mV ºC 20 ºC 5 µA 490 650 µA 360 1.8 0.05 450 1.854 0.5 µA V %/V 0mA < IOUT < 400mA 0.2 1 % ISW = -100mA, High-Side Switch ISW = 100mA, Low-Side Switch 0.65 0.55 0.6 0.85 0.75 0.85 1.6 Ω Ω A 1.8 2 2.2 MHz 100 VDAC = 1.3V VDAC = 0.6V (regulator on, not switching) VDAC = 0.6V, ILOAD = 0mA 3.0V< VIN < 4.5, ILOAD = 10mA Current Limit (Peak SW Current) Frequency February 2008 1 2.7 V V mV µA V 1 Maximum Duty Cycle Bypass Quiescent Current Quiescent Current Output Voltage µA 4 1.746 % M9999-022008-B Micrel, Inc. MIC2807 Parameter Condition Turn-On Time DAC Input Current Output Voltage/ DAC Voltage Bypass Switch Threshold Bypass Switch Hysteresis Bypass Transition Time Bypass Switch On-Resistance Bypass Switch Leakage Min Typ Max Units IOUT = 100µA 25 0.15 50 2 µs µA (internally set) 3 DAC Voltage required to enable bypass mode Line Regulation Load Regulation(6) Dropout Voltage(7) Ground Pin Current(8) Ripple Rejection Current Limit Output Voltage Noise LDO2 [VEN = 0V] Output Voltage Accuracy Line Regulation Load Regulation(6) Dropout Voltage(7) Ground Pin Current(8) Ripple Rejection Current Limit Output Voltage Noise February 2008 1.2 1.224 35 Delay from VDAC = 1.3V to VOUT = 0.90VIN VIN = 3.0V, IBYPASS = 100mA Bypass Over-Current Limit Current Limit Retry Time Current Limit Retry Duty Cycle LDO1/LDO2 [VEN = 0V] Total Ground Current(8) Turn-on Time LDO1 [VEN = 0V] Output Voltage Accuracy 1.176 V/V 10 95 1 VEN1 = VEN2 = 3.6V LDO1 or LDO2; CBYP = 0.1µF 1.4 Variation from nominal VOUT –40°C to +125°C VIN = VOUT +1V to 5.5V IOUT = 100µA to 30mA IOUT = 10mA; VOUT > 2.8V IOUT = 30mA; VOUT > 2.8V IOUT = 0mA; EN1 = GND f = up to 1kHz; CBYP = 0.1µF f = 1kHz – 20kHz; CBYP = 0.1µF VOUT = 0V CBYP = 0.1µF, 10Hz to 100kHz 5 µs mΩ 5 µA 2.5 A 40 12.5 % 0.02 0.2 20 55 70 190 70 45 300 32 –1 –2 40 150 µs –1 –2 225 mV 32 220 30 Variation from nominal VOUT –40°C to +125°C VIN = VOUT +1V to 5.5V IOUT = 100µA to 200mA IOUT = 50mA; VOUT > 2.8V IOUT = 150mA; VOUT > 2.8V IOUT = 200mA; VOUT > 2.8V IOUT = 0mA; EN2 = GND f = up to 1kHz; CBYP = 0.1µF f = 1kHz – 20kHz; CBYP = 0.1µF VOUT = 0V CBYP=0.1µF, 10Hz to 100kHz V 0.02 0.2 10 30 190 65 40 60 32 100 +1 +2 0.3 0.5 120 300 700 +1 +2 0.3 0.5 70 300 150 µA µs % % %/V % mV mV mV µA dB dB mA µVRMS % % %/V % mV mV µA dB dB mA µVRMS M9999-022008-B Micrel, Inc. MIC2807 Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) - TA) / θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. 4. Devices are ESD sensitive. Handling precautions recommended. 5. Specification for packaged product only. 6. Regulation is measured at constant junction temperature using low duty cycle pulse testing, changes in output voltage due to heating effects are covered by the thermal regulation specification. 7. Dropout voltage is defined as the input-to-output differential at which the output voltage drops 2% below its nominal value measured at 1V differential. 8. Ground pin current is the regulator quiescent current. February 2008 6 M9999-022008-B Micrel, Inc. MIC2807 Typical Characteristics (DC/DC) 1.2V OUT DC/DC Efficiency 100 90 100 90 80 80 VIN = 4.2V VIN = 3.6V VIN = 3V 50 40 30 20 10 20 10 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 0.5 100 90 0.5 2.5V OUT DC/DC Efficiency 100 90 80 70 VIN = 4.2V VIN = 3.6V VIN = 3V 60 50 40 30 40 30 20 20 10 0 0 10 0 0 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 0.5 DC/DC Switching Frequency vs. Input Voltage 2.8 1.5 VIN = 4.2V VIN = 3.6V VIN = 3V DC/DC Line Regulation 1.215 1.210 1.205 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 0.5 DC/DC Current Limit vs. Input Voltage 1.3 VOUT = 1.2V IOUT = 100mA VDAC = 0.4V 1.200 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) DC/DC Output Voltage vs. DAC Voltage 4.5 VIN = 4.2V 4.0 IOUT = 100mA 3.5 VDAC = 0.5V VOUT = 1.5V IOUT = 300mA 1.6 1.4 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) DC/DC Load Regulation x D V 2.0 1.5 1.8 AC 2.5 1.1 2.0 3 3.0 2.2 0.5 1.220 2.6 2.4 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 0.9 = 60 50 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 10 0 0 T 80 70 60 50 40 30 20 0 0 1.8V OUT DC/DC Efficiency VIN = 4.2V VIN = 3.6V VIN = 3V U 0 0 VIN = 4.2V VIN = 3.6V VIN = 3V 70 60 30 90 80 70 O 50 40 100 V 70 60 1.5VOUT DC/DC Efficiency Bypass Mode 1V OUT DC/DC Efficiency 1.0 0.5 0.7 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) 0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 DAC VOLTAGE (V) DC/DC Switching Frequency vs. Temperature 1.825 3.5 1.823 3.0 2.5 1.821 2.0 1.819 1.5 1.817 1.815 0 VIN = 3.6V VDAC = 0.5V VOUT = 1.5V IOUT = 300mA 1.0 VIN = 3.6V 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) February 2008 0.5 0.5 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 7 M9999-022008-B Micrel, Inc. MIC2807 Typical Characteristics (LDO1/LDO2) LDO2 Dropout Voltage vs. Output Current 35 LDO2 Load Regulation LDO2 Line Regulation 2.808 2.810 2.806 2.805 2.804 2.800 30 25 20 15 10 2.802 5 VOUT = 2.8V 0 3 90 6 9 12 15 18 21 24 27 30 OUTPUT CURRENT (mA) Power Supply Rejection Ratio LDO2 [IOUT=20mA] 80 70 2.800 0 100 90 80 5 10 15 20 25 30 OUTPUT CURRENT (mA) Power Supply Rejection Ratio LDO2 [IOUT=1mA] 50 30 VIN = 3.6V 20 VOUT = 2.8V 10 IOUT = 20mA COUT = 1µF 0 0.01 0.1 1 10 100 FREQUENCY (kHz) 1000 LDO1 Ground Current vs. Output Current 30 VIN = 3.6V 20 VOUT = 2.8V IOUT = 1mA 10 C OUT = 1µF 0 0.01 0.1 1 10 100 FREQUENCY (kHz) 310 2.790 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) 65 LDO1 Dropout Voltage vs. Temperature 55 50 40 40 IOUT = 15mA COUT = 1µF 60 70 60 60 250 2.795 VIN = 3.6V COUT = 1µF 50 1000 LDO1 Ground Current vs. Temperature VIN = 3.6V VOUT = 2.8V IOUT = 150mA 45 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) LDO1 Line Regulation 2.81 290 240 2.80 270 250 230 2.79 230 220 190 210 200 0 90 2.78 210 VIN = 3.6V VOUT = 2.8V 30 60 90 120 150 OUTPUT CURRENT (mA) Power Supply Rejection Ratio LDO1 [IOUT=5mA] 150 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 80 100 90 70 80 60 70 60 50 30 February 2008 Power Supply Rejection Ratio LDO1 [IOUT=100mA] IOUT = 100mA COUT = 2.2µF 2.76 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) 80 LDO1 Dropout Voltage vs. Output Current 60 50 40 30 30 1000 2.77 70 50 40 40 VIN = 3.6V 20 VOUT = 2.8V 10 IOUT = 5mA COUT = 2.2µF 0 0.01 0.1 1 10 100 FREQUENCY (kHz) VIN = 3.6V VOUT = 2.8V IOUT = 150mA 170 20 VIN = 3.6V V = 2.8V 10 COUT = 2.2µF OUT 0 0.1 1 10 100 FREQUENCY (kHz) 8 20 10 1000 0 5 VOUT = 2.8V 45 85 125 165 205 OUTPUT CURRENT (mA) M9999-022008-B Micrel, Inc. MIC2807 Typical Characteristics (LDO1/LDO2 cont.) 10 LDO1/LDO2 Output Noise Spectral Density 1 0.1 0.01 VIN = 4.2V VOUT = 2.8V COUT = 1µF 0.001 0.01 0.1 1 10 100 1000 10000 FREQUENCY (kHz) February 2008 9 M9999-022008-B Micrel, Inc. MIC2807 Functional Characteristics DC/DC PWM Waveforms VIN = 3.6V IOUT = 100mA VOUT = 1.8V L = 4.7µH VIN = 3.6V Output Voltage DC Coupled (1V/div) Inductor Current DC Coupled (100mA/div) Output Voltage AC Coupled (50mV/div) Enable Voltage DC Coupled (1V/div) Switch Voltage DC Coupled (2V/div) DC/DC Start-Up Waveforms COUT = 1µF Time (400ns/div) VOUT = 1.8V IOUT = 300mA L = 4.7µH COUT = 1µF Time (10µs/div) Output Voltage AC Coupled (200mV/div) DC/DC Load Transient 300mA VIN = 3.6V Output Current DC Coupled (100mA/div) VOUT = 1.8V L = 4.7µH COUT = 1µF 10mA Time (20µs/div) February 2008 10 M9999-022008-B Micrel, Inc. MIC2807 Functional Characteristics (cont.) LDO1 Start-Up Waveforms Output Current DC Coupled (200mV/div) Output Voltage DC Coupled (2V/div) Enable Voltage DC Coupled (2V/div) Output Voltage AC Coupled (50mV/div) LDO1 Load Transient VIN = 3.6V VOUT = 2.8V IOUT = 200mA COUT = 2.2µF 200mA 10mA VIN = 3.6V VOUT = 2.8V COUT = 2.2µF Time (10µs/div) February 2008 Time (20µs/div) 11 M9999-022008-B Micrel, Inc. MIC2807 Functional Diagram MIC2807 Block Diagram February 2008 12 M9999-022008-B Micrel, Inc. MIC2807 VIN VIN provides power to the LDO1 and the LDO2 control sections of the MIC2807. A minimum 1µF capacitor, 2.2µF recommended, should be placed as close as possible between the VIN and AGND pins. VIN must have the same voltage as AVIN*. Device Functional Description The MIC2807 is a power management IC with a single integrated step-down regulator and two low dropout regulators. LDO1 is a 200mA low dropout regulator and LDO2 is a 30mA low dropout regulator. The 500mA pulse-width-modulated (PWM) step-down regulator utilizes a dynamically adjustable output voltage for powering RF power amplifiers. By dynamically adjusting the output power as necessary, battery life can be dramatically improved in battery powered RF power amplifier applications. Also where high power is required, the step-down PWM regulator has a bypass mode where an internal 95mΩ switch shorts the OUT and PVIN pins together. OUT The OUT pin connects the internal bypass drain and the feedback signal to the output. The bypass applies the input voltage through a low resistance (95mΩ typical) PChannel MOSFET switch. The feedback signal provides the control path to set the output at 3 times the DAC voltage. SW The SW pin connects directly to the inductor and provides the switching current necessary to operate in PWM mode. Due to the high speed switching on this pin, the switch node should be routed away from sensitive nodes. Pin Functional Description PVIN PVIN (Power VIN) provides power to the MOSFETs for the step-down switching regulator section of the MIC2807, along with the current limit sensing circuitry. Due to the high switching speeds, a minimum 1µF capacitor is recommended close to PVIN and the power ground (PGND) pin for bypassing*. PGND PGND (Power GND) is the ground path for the MOSFETs in the step-down regulator section. The current loop for the power ground should be as small as possible and separate from the analog ground (AGND) loop*. AVIN AVIN (Analog VIN) provides power to the internal reference and control section of the step-down regulator. AVIN, VIN, and PVIN must all be tied together. Careful layout should be considered to ensure high frequency switching noise caused by PVIN is reduced before reaching AVIN*. AGND AGND (Analog GND) 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*. DAC The DAC pin is the control pin that sets the output voltage of the step-down regulator. The Output voltage is 3X the voltage set on the DAC pin (VOUT = VDAC x 3). When 1.2V or greater is applied to the DAC pin, the MIC2807’s step-down regulator enters bypass mode. In bypass mode, the input supply is connected to the output through a 95mΩ P-Channel MOSFET. LDO1 Regulated output voltage of the LDO1. Power is provided by VIN. Recommended output capacitance is 2.2µF. LDO2 Regulated output voltage of the LDO2. Power is provided by VIN. Recommended output capacitance is 1µF. EN/EN1/EN2 The EN pin provides a logic level control of the stepdown regulator output. In the off state, supply current of the device is greatly reduced (typically ≤1µA). Also, in the off state, the output drive and bypass switch are placed in a "tri-stated" condition, where both the high side P-channel MOSFET and the low-side N-channel are in an off or non-conducting state. EN1 provides logic control for LDO1, and EN2 provides logic control for LDO2. Placing a logic high voltage on any one of the respective enable pins (EN, EN1 or EN2) will turn-on (powering up the bias and control circuitry) that respective regulator (DC/DC, LDO1 or LDO2). Do not drive the enable pins above the supply voltage (AVIN and VIN). February 2008 BYP Filter capacitor for the voltage reference for the LDO1 and the LDO2. A 100nF capacitor is recommended from the BYP pin to ground. * Refer to PCB layout section of this data sheet for optimal layout principles. 13 M9999-022008-B Micrel, Inc. MIC2807 Inductor Selection The MIC2807 is designed for use with a 4.7µH inductor. Proper selection should ensure that the inductor can handle the maximum average and peak currents required by the load. Maximum current ratings of the inductor are generally 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 that 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 will not saturate the inductor. Peak inductor current can be calculated as follows: Component Selection Output Capacitor LDO1 output requires a 2.2µF ceramic capacitor, while the LDO2 and DC/DC regulator outputs require a 1µF ceramic capacitor. All output capacitor values can be increased to improve transient response, but performance has been optimized for a 2.2µF ceramic capacitor for LDO1 and 1µF ceramic capacitors for both the DC/DC regulator and LDO2. X7R/X5R dielectric-type ceramic capacitors are recommended because of their temperature performance. X5R/X7R-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 50% to 60% respectively over their operating temperature ranges. Input Capacitor For optimal bypassing a minimum 1µF ceramic, 2.2µF recommended, should be placed as close as possible to the VIN pin. X5R or X7R dielectrics are recommended for the input capacitor. Y5V dielectrics lose most of their capacitance over temperature and are therefore, not recommended. For high frequency filtering a minimum 1µF is recommended close to the VIN and PGND pins. Smaller case size capacitors are recommended due to their lower ESR and ESL. Please refer to the PCB layout section for an example of an appropriate circuit layout. February 2008 IPK: IOUT: VIN: VOUT: f: L: 14 ⎛ ⎞ V VOUT ⎜⎜1 − OUT ⎟⎟ VIN ⎠ ⎝ IPK = IOUT + 2× f ×L Peak Inductor Current Output/Load Current Input Voltage Output Voltage Switching Frequency of PWM Regulator Inductor Value M9999-022008-B Micrel, Inc. MIC2807 PCB Layout Layout Schematic February 2008 15 M9999-022008-B Micrel, Inc. MIC2807 Top Layer February 2008 16 M9999-022008-B Micrel, Inc. MIC2807 Bottom Layer February 2008 17 M9999-022008-B Micrel, Inc. MIC2807 Package Information ® 17-Pin 2.5mm x 2.8mm MLF (ML) 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. © 2006 Micrel, Incorporated. February 2008 18 M9999-022008-B