MIC2605/6 0.5A, 1.2MHz / 2MHz Wide Input Range Boost Regulator with Integrated Switch and Schottky Diode General Description Features The MIC2605/6 is a 1.2MHz/2MHz, PWM DC/DC boost switching regulator available in a 2mm x 2mm MLF® package. High power density is achieved with the MIC2605/6’s internal 40V/0.5A switch and schottky diode, allowing it to power large loads in a tiny footprint. The MIC2605/6 implements constant frequency 1.2MHz/2MHz PWM current mode control. The MIC2605/6 offers internal compensation that offers excellent transient response and output regulation performance. The high frequency operation saves board space by allowing small, low-profile external components. The fixed frequency PWM scheme also reduces spurious switching noise and ripple to the input power source. The MIC2605/6 is available in an 8-pin 2mm x 2mm MLF® leadless package. This package has an output overvoltage protection feature. The MIC2605/6 has an operating junction temperature range of –40°C to +125°C. Data sheets and support documentation can be found on Micrel’s web site at www.micrel.com. • • • • • • • • • • • • • • Wide input voltage range: 4.5V to 20V Output voltage adjustable to 40V 0.5A switch current and schottky diode MIC2605 operates at 1.2MHz MIC2606 operates at 2MHz Programmable soft start Stable with small size ceramic capacitors High efficiency Low input and output ripple <10µA shutdown current UVLO Output over-voltage and over-temperature protection 8-pin 2mm x 2mm MLF® package –40°C to +125°C junction temperature range Applications • TV-tuners • Broadband communications • TFT-LCD bias supplies • Bias supply • Positive output regulators • SEPIC converters • DSL applications • Local boost regulators ___________________________________________________________________________________________________________ Typical Application 10µH 32VOUT Efficiency VOUT 32V, 30mA MIC2605/6 VIN VIN = 12V EN 1µF 0.1µF VDD SS SW OUT FB 80 12.4K 70 60 50 1µF PGND 90 499 0.1µF 40 30 20 10 0 20 VIN = 12V 40 60 80 100 120 LOAD CURRENT (mA) 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 August 2008 M9999-080108-B Micrel, Inc. MIC2605/6 Ordering Information (2) Part Number Marking Code(1) Frequency Output Over Voltage Protection Temperature Range MIC2605YML WZ5 1.2MHz 40V –40° to +125°C 8-Pin 2mm x 2mm MLF® Pb-Free –40° to +125°C ® Pb-Free MIC2606YML WZ6 2MHz 40V Package Lead Finish 8-Pin 2mm x 2mm MLF Notes 1. Overbar ( 2. MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. ) symbol my not be to scale. ® Pin Configuration VOUT 1 8 PGND VIN 2 7 SW VDD 3 6 FB EN 4 5 SS 8-Pin 2mm x 2mm MLF® (ML) Pin Description Pin Number Pin Name 1 VOUT 2 VIN Supply (Input): 4.5V to 20V input voltage. 3 VDD Internal regulated supply. VDD should be connected to VIN when VIN ≤ 7V. 4 EN Enable (Input): Logic high enables regulator. Logic low shuts down regulator. 5 SS Soft start 6 FB Feedback (Input): 1.25V output voltage sense node. VOUT = 1.25V (1 + R1/R2). 7 SW Switch Node (Input): Internal power BIPOLAR collector. 8 PGND Power ground EP EPAD Exposed backside pad for thermal cooling. August 2008 Pin Function Output Pin: Connect to the output capacitor. 2 M9999-080108-B Micrel, Inc. MIC2605/6 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) .......................................................22V Switch Voltage (VSW)....................................... –0.3V to 40V Enable Voltage (VEN)......................................... –0.3V to VIN FB Voltage (VFB)............................................................. VDD Ambient Storage Temperature (Ts) ...........–65°C to +150°C ESD Rating(3) (MIC2605)................................................ 2kV ESD Rating(3) (MIC2606)............................................. 1.5kV Supply Voltage (VIN).......................................... 4.5V to 20V Junction Temperature (TJ) ........................ –40°C to +125°C Junction Thermal Resistance 2mm x 2mm MLF-8 (θJC) ...................................90°C/W Electrical Characteristics(4) TA = 25°C, VIN = VEN = 12V; unless otherwise noted. Bold values indicate –40°C ≤ TJ ≤ +125°C. Symbol Parameter VIN Input Voltage Range Condition VDD Internal Regulated Voltage Note 5 VULVO Under-voltage Lockout For VDD Min Typ 4.5 Max Units 20 V 2.4 V 5.8 1.8 2.1 V IQ Quiescent Current VFB = 2V (not switching) 4.2 6 mA ISD Shutdown Current VEN = 0V, Note 6 0.1 10 µA VFB Feedback Voltage 1.25 1.275 V 1.288 V IFB (±2%) 1.225 (±3%) (over temperature) 1.212 Feedback Input Current VFB = 1.25V –550 Line Regulation 8V ≤ VIN ≤ 14V, VOUT = 18V 0.04 Load Regulation 5mA ≤ IOUT ≤ 40mA, VOUT = 18V, Note 7 DMAX Maximum Duty Cycle MIC2605 MIC2606 85 80 ISW Switch Current Limit Note 7 0.5 nA 1 % 1.5 % % % 0.8 VSW Switch Saturation Voltage ISW = 0.5A 600 ISW Switch Leakage Current VEN = 0V, VSW = 18V 0.01 VEN Enable Threshold Turn ON Turn OFF A mV 5 µA 0.3 V V 1.5 IEN Enable Pin Current 20 40 µA fSW Oscillator Frequency (MIC2605) VEN = 12V 1.02 1.2 1.38 MHz Oscillator Frequency (MIC2606) 1.7 2 2.3 MHz VD Schottky Forward Drop ID = 1mA ID = 150mA 450 850 IRD Schottky Leakage Current VR = 30V VOVP Output Over-voltage Protection 15% Over programmed VOUT TJ Over-temperature Threshold Shutdown Hysteresis 10 mV mV 0.1 4 µA 15 20 % 150 °C 10 °C 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, θ JA, and the ambient temperature, TA. The maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. 2. The device is not guaranteed to function outside its operating rating. 3. IC devices are inherently ESD sensitive. Handling precautions required. Human body model rating: 1.5k in series with 100pF. 4. Specification for packaged product only. 5. Connect VDD pin to VIN pin when VIN ≤ 7V. 6. ISD = IVIN. 7. Guaranteed by design. August 2008 3 M9999-080108-B Micrel, Inc. MIC2605/6 Typical Characteristics Frequency vs. Input Voltage 2.0 Quiescent Current vs. Input Voltage 7 97 6 96 5 95 1.6 4 94 1.4 3 93 2 92 MIC2606 1.8 1.2 1.0 4 6 8 10 12 14 16 INPUT VOLTAGE (V) 18 Switch Saturation Voltage vs. Input Voltage 1100 1000 900 800 700 600 500 400 300 200 100 0 4 –50mA –0.25A –0.45A –0.65A –0.85A 6 –0.1A –0.3A –0.5A –0.7A 91 1 MIC2605 –0.15A –0.35A –0.55A –0.75A –0.2A –0.4A –0.6A –0.8A 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 0 1 1100 1000 900 800 700 600 500 400 300 200 100 0 5 7 9 11 13 15 17 19 INPUT VOLTAGE (V) –4.5V –5V –6V –7V –8V –9V –10V –11V –12V –15V –20 32.9 Load = 40mA 6 8 10 12 14 16 18 INPUT VOLTAGE (V) Feedback Voltage vs. Temperature 0.75 0.70 0.65 0.60 4 32VOUT Efficiency 12VIN 1.264 1.258 1.256 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 90 80 70 4.5VIN 60 50 40 40 30 30 20 20 10 10 8 12 16 20 24 28 32 36 40 LOAD CURRENT (mA) Switch Current Limit vs. Temperature 0 20 1000 0.95 VIN = 12V 40 60 80 100 120 LOAD CURRENT (mA) VSAT vs. Temperature ISW=750mA 1.262 1.260 EN = VIN 6 32VOUT Efficiency 50 1.00 Switch Current Limit vs. Input Voltage 0.85 SWITCH CURRENT (mA) 0 4 EN = VIN 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 0.80 60 33.0 1.00 6 0.95 70 33.1 90 4 0.90 80 33.2 1.266 3 90 33.3 32.8 4 No Switching FB Pin @ 2V Switch Saturation Voltage vs. Switch Current Line Regulation 33.4 Max Duty Cycle vs. Input Voltage 0.90 ISW=400mA 0.85 100 0.80 1.254 VIN = 12V Load = 100mA 1.250 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 1.252 August 2008 0.75 VIN = 12V 0.70 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 4 ISW=100mA 10 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) M9999-080108-B Micrel, Inc. MIC2605/6 Typical Characteristics (continued) 1.270 Enable Threshold ON vs. Temperature 1.265 100 98 Max Duty Cycle vs. Temperature 2.0 MIC2606 96 1.8 1.260 94 92 1.6 1.255 90 88 1.4 1.250 86 1.245 VIN = 12V 1.240 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 25 24 Frequency vs. Temperature Enable Current vs. Temperature 1.2 84 82 1.0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Shutdown Current vs. Temperature Quiescent Current vs. Temperature 0.100 0.090 22 21 4.22 4.20 0.085 20 19 0.080 18 0.075 17 16 0.070 VIN = 12V 15 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 4.30 4.28 4.26 4.24 0.095 23 MIC2605 VIN = 12V 80 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 4.18 4.16 4.14 VIN = 12V 0.065 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 4.12 VIN = 12V 4.10 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Thermal Derating 400 350 300 250 200 150 100 50 VIN = 12V VOUT = 18V 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) August 2008 5 M9999-080108-B Micrel, Inc. MIC2605/6 Functional Characteristics August 2008 6 M9999-080108-B Micrel, Inc. MIC2605/6 Functional Diagram VIN VDD FB VOUT OVP CMP Regulator EN OVP CL THERMAL UVLO BANDGAP 5.8V Bandgap SW OSC EA 1.25V S PWM CMP R SS + 1.2/2MHz Oscillator OSC + Ramp Generator CA PGND Figure 1. MIC2605/6 Block Diagram August 2008 7 M9999-080108-B Micrel, Inc. MIC2605/6 Functional Description EN The enable pin provides a logic level control of the output. In the off state, supply current of the device is greatly reduced (typically <0.1µA). Also, in the off state, the output drive is placed in a "tri-stated" condition, where bipolar output transistor is in an “off” or nonconducting state. Do not drive the enable pin above the supply voltage. The MIC2605/6 is a constant frequency, PWM current mode boost regulator. The block diagram is shown in Figure 1. The MIC2605/6 is composed of an oscillator, slope compensation ramp generator, current amplifier, gm error amplifier, PWM generator, and a 0.5A bipolar output transistor. The oscillator generates a 1.2MHz/ 2MHz clock. The clock’s two functions are to trigger the PWM generator that turns on the output transistor and to reset the slope compensation ramp generator. The current amplifier is used to measure the switch current by amplifying the voltage signal from the internal sense resistor. The output of the current amplifier is summed with the output of the slope compensation ramp generator. This summed current-loop signal is fed to one of the inputs of the PWM generator. The gm error amplifier measures the feedback voltage through the external feedback resistors and amplifies the error between the detected signal and the 1.25V reference voltage. The output of the gm error amplifier provides the voltage-loop signal that is fed to the other input of the PWM generator. When the current-loop signal exceeds the voltage-loop signal, the PWM generator turns off the bipolar output transistor. The next clock period initiates the next switching cycle, maintaining the constant frequency current-mode PWM control. SS The SS pin is the soft start pin which allows the monotonic buildup of output when the MIC2605/6 comes up during turn on. The SS pin gives the designer the flexibility to have a desired soft start by placing a capacitor SS to ground. A 0.1µF capacitor is used for in the circuit. FB The feedback pin (FB) provides the control path to control the output. For fixed output controller output is directly connected to feedback (FB) pin. SW The switch (SW) pin connects directly to the inductor and provides the switching current necessary to operate in PWM mode. Due to the high speed switching and high voltage associated with this pin, the switch node should be routed away from sensitive nodes. Pin Description PGND Power ground (PGND) is the ground path for the high current PWM mode. The current loop for the power ground should be as small as possible and separate from the Analog ground (AGND) loop. Refer to the layout considerations for more details. VIN VIN provides power to the MOSFETs for the switch mode regulator section. Due to the high switching speeds, a 1µF capacitor is recommended close to VIN and the power ground (PGND) pin for bypassing. Please refer to layout recommendations. VOUT VOUT pin is the cathode of pin of internal schottky diode. This pin is connected to output cap. At least 1µF cap is recommended very close to the VOUT pin and PGND. VDD The VDD pin supplies the power to the internal power to the control and reference circuitry. The VDD is powered from VIN. A small 0.1µF capacitor is recommended for bypassing. August 2008 8 M9999-080108-B Micrel, Inc. MIC2605/6 Component Selection Inductor Inductor selection is a balance between efficiency, stability, cost, size, and rated current. For most applications, a 10µH is the recommended inductor value; it is usually a good balance between these considerations. Large inductance values reduce the peak-to-peak ripple current, affecting efficiency. This has an effect of reducing both the DC losses and the transition losses. There is also a secondary effect of an inductor’s DC resistance (DCR). The DCR of an inductor will be higher for more inductance in the same package size. This is due to the longer windings required for an increase in inductance. Since the majority of input current (minus the MIC2605/6 operating current) is passed through the inductor, higher DCR inductors will reduce efficiency. To maintain stability, increasing inductor size will have to be met with an increase in output capacitance. This is due to the unavoidable “right half plane zero” effect for the continuous current boost converter topology. The frequency at which the right half plane zero occurs can be calculated as follows: Application Information DC-to-DC PWM Boost Conversion The MIC2605/6 is a constant frequency boost converter. It operates by taking a DC input voltage and regulating a higher DC output voltage. Figure 2 shows a typical circuit. Boost regulation is achieved by turning on an internal switch, which draws current through the inductor (L1). When the switch turns off, the inductor’s magnetic field collapses, causing the current to be discharged into the output capacitor through an internal Schottky diode. Voltage regulation is achieved through pulse-width modulation (PWM). 10µH VOUT 32V, 30mA MIC2605/6 VIN VIN = 12V EN 1µF 0.1µF VDD SS SW OUT FB 12.4K 1µF PGND 499 0.1µF FRHPZ = Figure 2. Typical Application Circuit Duty Cycle Considerations Duty cycle refers to the switch on-to-off time ratio and can be calculated as follows for a boost regulator: D = 1− 2 ⋅ π ⋅ L ⋅ IO The right half plane zero has the undesirable effect of increasing gain, while decreasing phase. This requires that the loop gain is rolled off before this has significant effect on the total loop response. This can be accomplished by either reducing inductance (increasing RHPZ frequency) or increasing the output capacitor value (decreasing loop gain). VIN VOUT The duty cycle required for voltage conversion should be less than the maximum duty cycle of 85%. Also, in light load conditions where the input voltage is close to the output voltage, the minimum duty cycle can cause pulse skipping. This is due to the energy stored in the inductor causing the output to overshoot slightly over the regulated output voltage. During the next cycle, the error amplifier detects the output as being high and skips the following pulse. This effect can be reduced by increasing the minimum load or by increasing the inductor value. Increasing the inductor value reduces peak current, which in turn reduces energy transfer in each cycle. Output Capacitor Output capacitor selection is also a trade-off between performance, size, and cost. Increasing output capacitance will lead to an improved transient response, but also an increase in size and cost. X5R or X7R dielectric ceramic capacitors are recommended for designs with the MIC2605/6. Y5V values may be used, but to offset their tolerance over temperature, more capacitance is required. Input capacitor A minimum 1μF ceramic capacitor is recommended for designing with the MIC2605/6. Increasing input capacitance will improve performance and greater noise immunity on the source. The input capacitor should be as close as possible to the inductor and the MIC2605/6, with short traces for good noise performance. Overvoltage Protection For the MIC2605/6 there is an over voltage protection function. If the output voltage overshoots the set voltage by 15% when feedback is high during input higher than output, turn on, load transients, line transients, load disconnection etc. the MIC2605/6 OVP ckt will shut the switch off saving itself and other sensitive circuitry downstream. August 2008 (D )2 ⋅ VO 9 M9999-080108-B Micrel, Inc. MIC2605/6 Feedback Resistors The MIC2605/6 utilizes a feedback pin to compare the output to an internal reference. The output voltage is adjusted by selecting the appropriate feedback resistor network values. The R2 resistor value must be less than or equal to 1kΩ (R2 ≤ 1kΩ). The desired output voltage can be calculated as follows: August 2008 ⎛ R1 ⎞ VOUT = VREF ⋅ ⎜ + 1⎟ R 2 ⎝ ⎠ where VREF is equal to 1.25V. 10 M9999-080108-B Micrel, Inc. MIC2605/6 L1 10µH 1 2 U1 MIC2605/6-YML J1 VIN 4.5V to 12V 2 C1 1µF/25V J2 GND J3 EN SW FB VDD SS PGND 3 J4 VOUT 32V R1 12.4k EN 6 C4 1µF/50V C5 N.U. 5 C3 0.1µF/50V R2 J5 GND 8 C2 0.1µF/50V 7 1 VOUT 4 R3 10k VIN Bill of Materials Item Part Number C1608X5R1E105K 06033D105MAT C1 08055D105MAT VJ0603Y104KXAAT C2 06035C104MAT GRM188R71C104KA01D VJ0603Y104KXAAT C3 06035C104MAT GRM188R71C104KA01D C4 08055D105MAT C5 N.U. L1 LQH43CN100K03 Manufacturer Description (1) Capacitor, 1µF, 25V, X5R, Size 0603 (2) Capacitor, 1µF, 25V, X5R, Size 0603 (2) Capacitor, 1µF, 50V, X5R, Size 0805 TDK AVX AVX (3) Vishay Qty. 1 Capacitor, 0.1µF, 50V, X7R, 0603 AVX(2) 1 Capacitor, 0.1µF, 50V, X7R, 0603 (4) Capacitor, 0.1µF, 16V, X7R, 0603 (3) Capacitor, 0.1µF, 50V, X7R, 0603 Murata Vishay (2) AVX 1 Capacitor, 0.1µF, 50V, X7R, 0603 (4) Capacitor, 0.1µF, 16V, X7R, 0603 Murata (2) AVX ----(4) Murata Capacitor, 1µF, 50V, X5R, Size 0805 1 ----- 1 10µH, 0.65mA, DCR 240mΩ 1 VLCF4020T-100MR85 TDK(1) 10uH, 0.85A-1.22A, DCR 120mΩ R1 CRCW06031242FKEA Vishay Dale(3) Resistor, 12.4k, 1%, 1/16W, Size 0603 1 R2 CRCW06034990FKEA Vishay Dale(3) Resistor, 499Ω, 1%, 1/16W, Size 0603 1 R3 CRCW060310K0FKEA (3) Resistor, 10k, 1%, 1/16W, Size 0603 1 U1 MIC2605/6-YML 0.5A, 1.2MHz/2MHz Wide Input Range Integrated Switch Boost Regulator 1 Vishay Dale Micrel, Inc.(5) Notes: 1. TDK: www.tdk.com 2. AVX: www.avx.com 3. Vishay: www.vishay.com 4. Murata: www.murata.com 6. Micrel, Inc.: www.micrel.com August 2008 11 M9999-080108-B Micrel, Inc. MIC2605/6 PCB Layout Recommendations Top Layer Bottom Layer August 2008 12 M9999-080108-B Micrel, Inc. MIC2605/6 Package Information 8-Pin 2mm x 2mm 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. © 2008 Micrel, Incorporated. August 2008 13 M9999-080108-B