MIC2808 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 MIC2808 integrates a high performance 600mA DC/DC step down regulator 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 MIC2808 improves efficiency in the handset without compromising quality. The MIC2808 has a 2MHz, constant frequency pulse width modulated (PWM) DC/DC regulator 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 regulator 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 regulator 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 regulator along with dual low noise LDO regulators enables a very quiet and efficient solution for mobile applications. The MIC2808 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 2.0mm x 2.5mm TMLF 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 16-pin 2.0mm x 2.5mm TMLF® Package Thermal shutdown protection Current limit protection RF PA Power Supply DC/DC Regulator • 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 WiMAX/Wibro modules WiFi modules Power amplifier modules (PAMs) with linear PAs Typical Application 4.5 DC/DC Output Voltage vs. DAC Voltage x 3 3.0 V D AC 2.5 T O U V 1.5 = 2.0 Bypass Mode VIN = 4.2V 4.0 IOUT = 100mA 3.5 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 July 2009 M9999-071709-A Micrel, Inc. MIC2808 Ordering Information Marking Code Part Number MIC2808-NNYFT NNYJ LDO1/LDO2 Voltage(3) Junction Temp. Range 2.85V/2.85V –40°C to +125°C Package(1) 16-Pin 2.0mm x 2.5mm Thin MLF Lead Finish(2) ® Pb-Free Note: ® 1. Thin MLF = Pin 1 identifier. ® 2. Thin MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is halogen free. 3. Contact Micrel for other output voltages. OUT OUT LDO2 Pin Configuration LDO1 PGND PVIN BYP EN1 DAC AVIN EN EN2 NC SW AGND VIN 16-Pin 2.0mm x 2.5mm Thin MLF® (FT) (Top View) July 2009 2 M9999-071709-A Micrel, Inc. MIC2808 Pin Description Pin Number Pin Name 1 LDO1 2 VIN LDO1 and LDO2 Supply Voltage. Must be connected to PIN 9 (AVIN). 3 EN2 Enables the LDO2 regulator. Do not leave floating. 4 BYP Filter capacitor for LDO1 and LDO2 internal voltage reference. Connect a 0.1µF capacitor-to-ground. 5 DAC DAC Control Input (Analog Voltage Input). Provides control of output voltage of DC/DC regulator. 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. 6 AGND 7 NC 8 EN 9 AVIN Pin Function Output of the LDO1. Signal ground. No Connect. Enables the DC/DC Regulator. Do not leave floating. Supply voltage for DC/DC regulator control circuitry and reference voltage circuit. Must be connected to PIN 2 (VIN). 10 EN1 Enables LDO1 Regulator. Do not leave floating. 11 PVIN Supply Voltage: Requires bypass capacitor to ground. 12 SW Switch: Internal power MOSFET output switches of DC/DC regulator. 13 PGND 14, 15 OUT Drain of internal bypass switch, also serves as feedback for the internal regulator. 16 LDO2 Output of the LDO2. July 2009 Power ground. 3 M9999-071709-A Micrel, Inc. MIC2808 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 2.0mmx2.5mm TMLF-16 (θJA)...........................96°C/W Electrical Characteristics(5) DC/DC Regulator 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 Supply Voltage Range Total Quiescent Current Enable Pin Threshold Condition Min 2.7 VEN = VEN1 = VEN2 = 3.6V VDAC = 0.6V (DC/DC: not switching) Logic Low Logic High (turn-on) V µA 70 0.01 1 V V mV µA 2.6 2.7 V 85 160 20 mV ºC ºC 1 5 µA 490 650 µA 360 1.8 0.05 450 1.854 µA V %/V 100 VDAC = 1.3V VDAC = 0.6V (regulator on, not switching) VDAC = 0.6V, ILOAD = 0mA 3.0V< VIN < 4.5, ILOAD = 10mA 1.746 % 0.5 0mA < IOUT < 400mA 0.2 ISW = -100mA, High-Side Switch ISW = 100mA, Low-Side Switch 0.65 0.55 0.59 0.85 0.7 0.8 1.6 Ω Ω A 1.8 2 2.2 MHz Current Limit (Peak SW Current) Frequency July 2009 5.5 0.4 Maximum Duty Cycle Output Voltage Line Regulation Output Voltage Load Regulation Switch On-Resistance Units 1.3 Shutdown Temperature Hysteresis Total Shutdown Current VEN = VEN1 = VEN2 = 0V DC/DC Regulator [VEN1 = VEN2 = 0V] Bypass Quiescent Current Quiescent Current Output Voltage Max 480 Enable Pin Hysteresis Enable Pin Input Current Under-Voltage Lockout Threshold UVLO Hysteresis Shutdown Temperature Typ 4 % M9999-071709-A Micrel, Inc. MIC2808 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 July 2009 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 0.5 100 300 700 +1 +2 0.3 0.5 60 300 150 µA µs % % %/V % mV mV mV µA dB dB mA µVRMS % % %/V % mV mV µA dB dB mA µVRMS M9999-071709-A Micrel, Inc. MIC2808 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. July 2009 6 M9999-071709-A Micrel, Inc. MIC2808 Typical Characteristics (DC/DC) 1.2V OUT DC/DC Efficiency 100 90 100 90 80 80 VIN = 4.2V VIN = 3.6V VIN = 3V 70 60 50 40 20 10 20 10 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 0.5 100 90 60 50 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 0.5 80 70 VIN = 4.2V VIN = 3.6V VIN = 3V 60 50 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 0.1 0.2 0.3 0.4 OUTPUT CURRENT (A) 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 x D V T U O V 0.9 = 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 10 0 0 2.5V OUT DC/DC Efficiency 100 90 80 70 VIN = 4.2V VIN = 3.6V VIN = 3V 40 30 20 0 0 1.8V OUT DC/DC Efficiency 90 80 70 VIN = 4.2V VIN = 3.6V VIN = 3V 50 40 30 0 0 100 70 60 30 1.5V OUT DC/DC Efficiency Bypass Mode 1V OUT DC/DC Efficiency 1.0 0.5 1.4 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) 0.7 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) DC/DC Load Regulation DC/DC Switching Frequency vs. Temperature 0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 DAC VOLTAGE (V) 3.5 1.825 3.0 1.823 2.5 1.821 2.0 1.819 1.5 1.817 1.815 0 July 2009 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) 0.5 0.5 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 7 M9999-071709-A Micrel, Inc. MIC2808 Typical Characteristics (LDO1/LDO2) LDO2 Dropout Voltage vs. Output Current 35 LDO2 Line Regulation LDO2 Load Regulation 2.854 2.860 2.852 2.855 2.850 2.850 30 25 20 15 10 2.848 5 VOUT = 2.85V 0 36 90 2.845 VIN = 3.6V COUT = 1µF 91 21 51 82 12 42 73 0 OUTPUT CURRENT (mA) Power Supply Rejection Ratio LDO2 [I OUT =20mA] 80 70 60 50 40 30 VIN = 3.6V 20 VOUT = 2.85V I = 20mA 10 OUT COUT = 1µF 0 0.01 0.1 11 0 100 FREQUENCY (kHz) 1000 LDO1 Ground Current vs. Output Current 250 2.846 05 100 90 10 15 20 25 30 OUTPUT CURRENT (mA) Power Supply Rejection Ratio LDO2 [I OUT =1mA] 80 70 60 50 40 30 VIN = 3.6V 20 VOUT = 2.85V I = 1mA 10 COUT = 1µF OUT 0 0.01 0.1 11 0 100 FREQUENCY (kHz) 310 IOUT = 15mA COUT = 1µF 2.840 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 60 55 50 1000 LDO1 Ground Current vs. Temperature VOUT = 2.85V IOUT = 150mA 45 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) LDO1 Line Regulation 2.86 290 240 2.85 270 250 230 2.84 230 220 190 210 200 03 90 2.83 210 VIN = 3.6V VOUT = 2.85V 06 09 0 120 150 OUTPUT CURRENT (mA) Power Supply Rejection Ratio LDO1 [I OUT =5mA] 150 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 100 80 90 70 80 60 70 50 40 30 VIN = 3.6V 20 VOUT = 2.85V IOUT = 5mA 10 COUT = 2.2µF 0 0.01 0.1 11 0 100 FREQUENCY (kHz) July 2009 VIN = 3.6V VOUT = 2.85V IOUT = 150mA 170 Power Supply Rejection Ratio LDO1 [I OUT =100mA] IOUT = 100mA COUT = 2.2µF 2.81 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 70 60 60 50 50 40 40 30 30 1000 2.82 20 VIN = 3.6V = 2.85V V 10 COUT = 2.2µF OUT 0 0.1 1 10 100 FREQUENCY (kHz) 8 20 10 1000 0 5 VOUT = 2.85V 45 85 125 165 205 OUTPUT CURRENT (mA) M9999-071709-A Micrel, Inc. MIC2808 Typical Characteristics (LDO1/LDO2 cont.) 10 LDO1/LDO2 Output Noise Spectral Density 1 0.1 0.01 VIN = 4.2V VOUT = 2.85V COUT = 1µF 0.001 0.01 0.1 July 2009 1 10 100 1000 10000 FREQUENCY (kHz) 9 M9999-071709-A Micrel, Inc. MIC2808 Functional Characteristics DC/DC PWM Waveforms VIN = 3.6V IOUT = 100mA VOUT = 1.8V L = 4.7µH VIN = 3.6V Output Voltag e DC Coupled (1V/div) Inductor Current DC Coupled (100mA/div) Output Voltage AC Coupled (10mV/div) Enable Voltag e DC Coupled (1V/div) Switch Voltage DC Coupled (2V/div) DC/DC Start-Up Waveforms COUT = 1µF VOUT = 1.8V IOUT = 300mA L = 4.7µH COUT = 1µF Time (10µs/div ) Time (400ns/div) Output Voltag e 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 ) July 2009 10 M9999-071709-A Micrel, Inc. MIC2808 Functional Characteristics (continued) LDO1 Load Transient Enable Voltage DC Coupled (2V/div) Output Voltage AC Coupled (50mV/div) LDO1 Start-Up Waveforms Output Current DC Coupled (200mV/div) Output Voltage DC Coupled (2V/div) 200mA VIN = 3.6V VOUT = 2.85V IOUT = 200mA COUT = 2.2µF VIN = 3.6V VOUT = 2.85V COUT = 2.2µF Time (10µs/div) July 2009 10mA Time (20µs/div) 11 M9999-071709-A Micrel, Inc. MIC2808 Functional Diagram MIC2808 Block Diagram July 2009 12 M9999-071709-A Micrel, Inc. MIC2808 VIN VIN provides power to the LDO1 and the LDO2 control sections of the MIC2808. 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 MIC2808 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 connects 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 three 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 MIC2808, 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 MIC2808’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). July 2009 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 M9999-071709-A Micrel, Inc. MIC2808 Inductor Selection The MIC2808 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. IPK = IOUT 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. July 2009 IPK: IOUT: VIN: VOUT: f: L: 14 ⎛ ⎞ V VOUT ⎜⎜1 − OUT ⎟⎟ VIN ⎠ ⎝ + 2× f ×L Peak Inductor Current Output/Load Current Input Voltage Output Voltage Switching Frequency of PWM Regulator Inductor Value M9999-071709-A Micrel, Inc. MIC2808 Typical Application Circuit LDO2 GND C3 1µF 6.3V OUT LDO2 OUT VIN VIN VIN GND EN2 DAC PVIN C8 2.2µF 6.3V AVIN C6 1µF 6.3V VIN EN2 C2 1µF 6.3V VOUT SW C1 2.2µF 6.3V LDO1 L1 4.7µH/1A LDO1 MIC2808-xxYFT BYP C4 0.1µF 6.3V C7 1µF 6.3V EN EN EN1 EN1 DAC C5 1µF 6.3V NC AGND PGND Bill of Materials Item Part Number Manufacturer (1) Description Qty. C1, C8 C1608X5R0J225K TDK 2.2µF Ceramic Capacitor, 6.3V, X5R, Size 0603 2 C2, C3, C5-C7 C1608X5R0J105K TDK(1) 1µF Ceramic Capacitor, 6.3V, X5R, Size 0603 5 C4 C1608X5R0J104K TDK(1) 0.1µF Ceramic Capacitor, 6.3V, X5R, Size 0603 1 VLS3012T-4R7M1R0 L1 4.7µH, 1.2A, 130mΩ, L3.0mm x W3.0mm x H1.2mm (3) CDH3D13-4R7NC Sumida ME3220-472MLB Coilcraft(4) LQH32CN4R7M53 MIPF2520D4R7 U1 TDK (1) MIC2808-xxYFT (5) Murata FDK (6) Micrel, Inc.(7) 4.7µH, 1.15A, 175mΩ, L3.0mm x W3.0mm x H1.4mm 1 4.7µH, 1.4A, 190mΩ, L3.2mm x W2.5mm x H2.0mm 4.7µH, 650mA, 150mΩ, L3.2mm x W2.5mm x H1.55mm 4.7µH, 1.1A, 110mΩ, L2.5mm x W2.0mm x H1.0mm 2MHz 600mA Buck with DAC Input, Bypass Switch and Dual Low Noise 200mA/30mA LDOs 1 Notes: 1. TDK: www.tdk.com 2. Vishay: www.vishay.com 3. Sumida: www.sumida.com 4. Coilcraft: www.coilcraft.com 5. Murata: www.murata.com 6. FDK: www.fdk.co.jp 7. Micrel, Inc.: www.micrel.com July 2009 15 M9999-071709-A Micrel, Inc. MIC2808 Top Layer July 2009 16 M9999-071709-A Micrel, Inc. MIC2808 Bottom Layer July 2009 17 M9999-071709-A Micrel, Inc. MIC2808 Package Information ® 16-Pin 2.0mm x 2.5mm FC-TMLF (FT) 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. © 2009 Micrel, Incorporated. July 2009 18 M9999-071709-A