MIC3202/MIC3202-1 High-Brightness LED Driver with Integrated MOSFET and High-Side Current Sense General Description Features The MIC3202 is a hysteretic, step-down, constant-current, High-Brightness LED (HB LED) driver. It provides an ideal solution for interior/exterior lighting, architectural and ambient lighting, LED bulbs, and other general illumination applications. The MIC3202 is well suited for lighting applications requiring a wide-input voltage range. The hysteretic control gives good supply rejection and fast response during load transients and PWM dimming. The high-side current sensing and on-chip current-sense amplifier delivers LED current with ±5% accuracy. An external high-side currentsense resistor is used to set the output current. The MIC3202 offers a dedicated PWM input (DIM) which enables a wide range of pulsed dimming. High-frequency switching operation of up to 1MHz allows the use of smaller external components, minimizing space and cost. The MIC3202 offers a frequency dither feature for low-EMI applications. The MIC3202 operates over a junction temperature from −40°C to +125°C and is available in an 8-pin e-PAD SOIC package. A dither disabled version MIC3202-1 is also available in the same package as the MIC3202. • • • • • • • • • • • • Datasheets and support documentation can be found on Micrel’s web site at: www.micrel.com. 6V to 37V input voltage range High efficiency (>90%) ±5% LED current accuracy MIC3202: Dither enabled for low EMI MIC3202-1: Dither disabled High-side current sense (up to 1A) Dedicated dimming control input Hysteretic control (no compensation required) Up to 1MHz switching frequency Adjustable constant LED current Over-temperature protection −40°C to +125°C junction temperature range Applications • • • • • • Architectural, industrial, and ambient lighting LED bulbs Indicators and emergency lighting Street lighting Channel letters 12V lighting systems (MR-16 bulbs, under-cabinet lighting, garden/pathway lighting) _________________________________________________________________________________________________________________________ Typical Application Efficiency vs. Input Voltage 100 6LED 8LED EFFICIENCY (% ) 4LED 95 2LED 90 85 ILED = 1A L = 47uH 80 6 14 22 30 38 INPUT VOLTAGE (V) MIC3202 Step-Down LED Driver 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 2010 M9999-091710-A Micrel, Inc. MIC3202/MIC3202-1 Ordering Information (1) Part Number Marking Junction Temperature Range Package PWM MIC3202YME MIC3202YME −40°C to +125°C 8-Pin SOIC Dither MIC3202-1YME −40°C to +125°C 8-Pin SOIC Non-Dither MIC3202-1YME Note: 1. ® YM is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration 8-Pin ePAD SOIC MIC3202/MIC3202-1 Pin Description Pin Number Pin Name 1 VCC 2 CS Current-Sense Input. The CS pin provides the high-side current sense to set the LED current using an external sense resistor. 3 VIN Input Power Supply. The VIN pin is the input supply pin to the internal circuitry and the positive input to the current sense comparator. Due to the high frequency switching noise, a 1µF ceramic capacitor is recommended to be placed as close as possible to VIN pin and the power ground (PGND) pin for bypassing. Please refer to layout recommendations. 4 AGND Pin Function Voltage Regulator Output. The VCC pin supplies the power to the internal circuitry. The VCC is the output of a linear regulator which is powered from VIN. A 1µF ceramic capacitor is recommended for bypassing and should be placed as close as possible to the VCC and AGND pins. Ground pin for analog circuitry. Internal signal ground for all low power sections. 5 EN Enable Input. The EN pin provides a logic level control of the output. The voltage has to be 2.0V or higher to enable the current regulator. The output stage is also gated by the DIM input. When the EN pin is pulled low, the regulator goes to off state and the supply current of the device is greatly reduced (below 1µA). 6 DIM PWM Dimming Input. The DIM pin provides the control for brightness of the LED. A PWM input can be used to control the brightness of LED. DIM high enables the output and its voltage has to be at least 2.0V or higher. DIM low disables the output, regardless of EN “high” state. 7 PGND Power Ground pin for Internal Power FET. Power Ground (PGND) is the ground path for the high current. 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. 8 LX Drain of Internal Power MOSFET. The LX pin connects directly to the inductor and provides the switching current necessary to operate in hysteretic mode. Due to the high frequency switching and high voltage associated with this pin, the switch node should be routed away from sensitive nodes. EP GND September 2010 Connect to PGND. 2 M9999-091710-A Micrel, Inc. MIC3202 Absolute Maximum Ratings (1, 2) Operating Ratings (3) VIN to PGND .................................................. −0.3V to +42V VLX to PGND........................................ −0.3V to (VIN + 0.6V) VCS to PGND ....................................... −0.3V to (VIN + 0.3V) VEN to AGND ....................................... −0.3V to (VIN + 0.3V) VDIM to AGND ...................................... −0.3V to (VIN + 0.3V) VCC to PGND ................................................ −0.3V to +6.0V PGND to AGND .......................................... −0.3V to + 0.3V Junction Temperature ................................................ 150°C Storage Temperature Range .................... −60°C to +150°C Lead Temperature (Soldering, 10sec) ....................... 260°C Supply Voltage (VIN).......................................... 6.0V to 37V Enable Voltage (VEN) .............................................. 0V to VIN Dimming Voltage (VDIM)................................................................. 0V to VIN Junction Temperature (TJ) ........................ −40°C to +125°C Junction Thermal Resistance SOIC (θJA) ..........................................................41°C/W SOIC (θJC).......................................................14.7°C/W Electrical Characteristics (4) VIN = VEN = VDIM = 12V; CVCC = 1.0µF; TJ = 25°C, bold values indicate −40°C ≤ TJ ≤ +125°C; unless noted. Symbol Parameter Condition Min. Typ. Max. Units Input Supply 6.0 VIN Input Voltage Range (VIN) IS Supply Current LX Pin = open ISD Shut Down Current VEN = 0V; TJ = from -40ºC to 85ºC UVLO VIN UVLO Threshold UVLOHYS VIN UVLO Hysteresis VIN Rinsing 37.0 V 1.75 mA 0.05 5 µA 4 4.5 1.2 3.2 500 V mV VCC Supply VCC VCC Output Voltage VCS = VIN = 12V, ICC = 10mA 4.5 5 5.5 V Current Limit VCS(MAX) Current-Sense Upper Threshold VCS(MAX ) = VIN − VCS 199 212 225 mV VCS(MIN) Current-Sense Lower Threshold VCS(MIN ) = VIN − VCS 165 177 189 mV VCS Hysteresis VCSHYS 35 Current-Sense Response Time Current-Sense Input Current VCS Rising 60 VCS Falling 40 VIN - VCS = 200mV mV ns 3 µA 1 MHz Frequency FMAX Maximum Switching Frequency Dithering (MIC3202) VDITH FDITHER VCS Hysteresis Dithering Range(5) Frequency Dithering Range (5) % of Switching Frequency ±6 mV ±12 % Enable Input ENHI 2.0 EN Logic Level High V 0.4 EN Logic Level Low ENLO EN Bias Current Start-up Time September 2010 VEN = 12V 30 60 VEN = 0V 0.1 1 From EN Pin going high to LX going low 30 3 V µA µs M9999-091710-A Micrel, Inc. MIC3202 Electrical Characteristics (4) VIN = VEN = VDIM = 12V; CVCC = 1.0µF; TJ = 25°C, bold values indicate −40°C ≤ TJ ≤ +125°C; unless noted. Symbol Parameter Condition Min. Typ. Max. Units Dimming Input DIMHI 2.0 DIM Logic Level High V 0.4 DIM Logic Level Low DIMLO fDIM DIM Bias Current VDIM = 12V 20 35 VDIM = 0V 0.1 1 Maximum Dimming Frequency V µA 20 kHz 275 625 mΩ 5 50 µA Internal MOSFET RDS(ON) MOSFET RDS(ON) ILX = 200mA LX Leakage Current VEN = 0V; VIN = VLX = 37V Thermal Protection TLIM Over-Temperature Shutdown TLIMHYS Over-Temperature Shutdown Hysteresis TJ Rising 160 20 °C Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 3. The device is not guaranteed to function outside its operating rating. 4. Specification for packaged product only. 5. Guaranteed by design. September 2010 4 M9999-091710-A Micrel, Inc. MIC3202 Typical Characteristics Efficiency vs. Input Voltage LED Current Normalized vs. Input Voltage 100 95 2LED 90 1LED 85 80 ILED = 1A L = 47uH 75 ILED = 1A L = 47uH ILED = 1A L = 47uH 1.01 2LED 4LED 0.99 1LED 14 22 30 6 14 22 100% 30 38 500 1LED 250 6LED 22 14 50% 1LED 25% 30 ILED = 1A L = 47uH 0% 38 30 38 2.5 2.0 1.5 1.0 VOUT = OPEN 0.5 VCC = 5V NO-SWITCHING 0.0 6 14 INPUT VOLTAGE (V) 22 30 6 38 VIN Shutdown Current vs. Input Voltage 14 22 30 38 INPUT VOLTAGE (V) INPUT VOLTAGE (V) VCC Voltage vs. Input Voltage 0.5 22 3.0 8LED 75% 8LED 0 8LED 1LED 6 SUPPLY CURRENT (mA) DUTY CYCLE (%) 750 6LED INPUT VOLTAGE (V) 2LED 4LED 4LED VIN Supply Current vs. Input Voltage 6LED 4LED ILED = 1A L = 47uH 14 -1.0% Duty Cycle vs. Input Voltage 1000 2LED 2LED 0.0% INPUT VOLTAGE (V) Switching Frequency vs. Input Voltage 6 1.0% -2.0% 38 INPUT VOLTAGE (V) CS Voltage vs. Input Voltage 5.050 250 VLED =3.5V ILED =1A 0.3 0.2 0.1 5.025 CS VOLTAGE (mV) V CC VOLTAGE (V) 0.4 5.000 4.975 4.950 14 22 30 38 Enable Bias Current vs. Enable Voltage 125 14 22 30 38 6 DIMMING BIAS CURRENT (µA) 100 75 50 VIN = VEN VLED =OPEN ILED = 0A 14 22 30 ENABLE VOLTAGE (V) September 2010 38 22 30 INPUT VOLTAGE (V) Dimming Bias Current vs. Dimming Voltage Switch RDSON vs. Input Voltage 38 425 75 50 VIN = VDIM 25 375 325 275 VLED =OPEN VLED = 3.5V ILED = 0A ILED = 1A 225 0 0 14 INPUT VOLTAGE (V) 100 6 VCS MIN 175 150 6 INPUT VOLTAGE (V) 25 200 ILED = 0A 0.0 6 VCS MAX 225 VLED = OPEN V EN = 0V SWITCH RDSON (mΩ) SWITCHING FREQUENCY (kHz) 8LED 0.98 6 SHUTDOWN CURRENT (µA) 6LED 1.00 LED CURRENT (%) 8LED LED CURRENT NORM (A) EFFICIENCY (% ) 2.0% 1.02 6LED 4LED ENABLE BIAS CURRENT (µA) LED Current Accuracy vs. Input Voltage 6 14 22 30 DIMMING VOLTAGE (V) 5 38 6 14 22 30 38 INPUT VOLTAGE (V) M9999-091710-A Micrel, Inc. MIC3202 Typical Characteristics (Continued)` SHUTDOWN CURRENT (µA) ILED = 0A 1.0 0.5 0.3 0.2 0.1 -20 10 40 70 100 130 -50 -20 10 40 70 100 TEMPERATURE (°C) TEMPERATURE (°C) Switching Frequency vs. Temperature Enable Bias Current vs. Temperature 40 ENABLE BIAS CURRENT (µA) 340 VIN = 12V VLED = 3.5V 330 ILED = 1A L = 47uH 320 310 300 -20 10 40 70 100 130 ILED = 1A L = 47uH -20 10 40 70 100 VCC Voltage vs. Temperature 5.20 ILED = 0A 35 30 25 5.10 5.00 4.90 VIN = 12V VLED = OPEN ILED = 0A 4.80 -20 10 40 70 100 130 -50 -20 10 40 70 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) CS Voltage vs. Temperature Switch RDSON vs. Temperature Case Temperature vs. Input Voltage CASE TEMPERATURE (º C) SWITCH RDSON (Ω) VCS MAX VIN = 12V 200 VLED = 3.5V ILED = 1A L = 47uH VCS MIN 175 350 300 VIN = 12V 250 150 200 10 40 70 100 -20 10 Switch Voltage vs. Switch Current 40 70 100 130 SWITCH RDSON (mΩ) 250 200 150 100 VLED = 3.5V 270 0.8 SWITCH CURRENT (A) September 2010 1.0 0.0 0.3 0.5 0.8 SWITCH CURRENT (A) 6 30 38 300 275 VIN = 12V 22 Switch Voltage vs. Switch Current 280 VLED = 3.5V 14 INPUT VOLTAGE (V) 285 VIN = 12V 0 0.5 VLED = 3.5V ILED = 1A L = 47uH 1oz/3.5 Sq Inch 6 Switch RDSON vs. Switch Current 290 300 0.3 30 TEMPERATURE (°C) TEMPERATURE (°C) 50 40 20 -50 130 SWITCH VOLTAGE (mV) -20 130 50 400 225 130 TEMPERATURE (°C) ISW = 0.2A SWITCH VOLTAGE (mV) VLED = 3.5V VLED = OPEN 450 0.0 VIN = 12V Falling -50 VIN =VEN = 12V -50 250 -50 3.5 130 20 -50 Rising 4.0 3.0 0 -50 SWITCHING FREQUENCY (kHz) VIN = 12V VEN = 0V V CC VOLTAGE (V) 0.0 CS VOLTAGE (mV) 4.5 0.4 VIN =VIN = 12V VLED = OPEN 1.5 VIN UVLO Threshold vs. Temperature VIN UVLO THRESHOLD (V) 2.0 VIN SUPPLY CURRENT (mA) Shutdown Current vs. Temperature VIN Supply Current vs. Temperature 1.0 250 200 150 100 VLED = 3.5V 50 VIN = 12V 0 0.0 0.3 0.5 0.8 1.0 SWITCH CURRENT (A) M9999-091710-A Micrel, Inc. MIC3202 Functional Characteristics September 2010 7 M9999-091710-A Micrel, Inc. MIC3202 Functional Characteristics (Continued) September 2010 8 M9999-091710-A Micrel, Inc. MIC3202 Functional Diagram Figure 1. MIC3202/MIC3202-1 Functional Block Diagram Functional Description The MIC3202 is a hysteretic step-down driver which regulates the LED current over wide input voltage range and capable of driving up to eight 1A LEDs in series. The device operates from a 6V to 37V input. When the input voltage reaches 6V, the internal 5V VCC is regulated and the LX pin is pulled low if the EN pin and DIM pin are high. The inductor current builds up linearly. When the CS pin voltage hits VCS(MAX) with respect to VIN, the MOSFET turns off and the Schottky diode takes over and returns the current to VIN. Then the current through inductor and LEDs starts decreasing. When CS pin hits VCS(MIN), the MOSFET turns on and the cycle repeats. September 2010 The frequency of operation depends upon the input voltage, total LED voltage drop, LED current and temperature. The calculation for frequency of operation is given in the Application Information section. The MIC3202 has an EN pin which gives the flexibility to enable and disable the output with logic high and low signals. The MIC3202 also has a DIM pin which can turn on and off the LEDs if EN is in HIGH state. This DIM pin controls the brightness of the LED by varying the duty cycle of DIM pin from 1% to 99%. 9 M9999-091710-A Micrel, Inc. MIC3202 Application Information The internal block diagram of the MIC3202 is shown in Figure 1. The MIC3202 is composed of a current-sense comparator, voltage and current reference, 5V regulator and MOSFET. Hysteretic mode control, also called bang-bang control, is a topology that does not employ an error amplifier, using an error comparator instead. The inductor current is controlled within a hysteretic window. If the inductor current is too small, the power MOSFET is turned on; if the inductor current is large enough, the power MOSFET is turned off. It is a simple control scheme with no oscillator and no loop compensation. Since the control scheme does not need loop compensation, it simplifies design and avoids problems of instability. Transient response to load and line variation is very fast and only depends on propagation delay. This makes the control scheme very popular to achieve low dimming duty cycles. LED Current and RCS The main function of the MIC3202 is to control the LED current accurately within ±5% of the set current. A highside RCS resistor sets LED current. The following equation gives the RCS value: Frequency of Operation To calculate the frequency spread across input supply: VL = L ΔIL Δt L is the inductance, ∆IL is fixed (the value of the hysteresis): ΔIL = VCS(MAX ) - VCS(MIN) RCS VL is the voltage across inductor L which varies by supply. For current rising (MOSFET is ON): tr = L ΔIL VL _ RISE where: VL_RISE = VIN − ILED × RCS − VLED. For current falling (MOSFET is OFF): RCS = 1 x( 2 VCS(MAX ) + VCS(MIN) ILED ) tf = L RCS (Ω) ILED (A) I2R (W) Size (SMD) 1.33 0.15 0.03 0603 0.56 0.35 0.07 0805 0.4 0.5 0.1 0805 0.28 0.7 0.137 0805 0.2 1.0 0.2 1206 ΔI L VL _ FALL where: VL_FALL = VD + ILED × RCS + VLED 1 T = t r + t f , f SW = T (V + I ×R + V ) × (V - I ×R - V ) fSW = D LED CS LED IN LED CS LED L × ΔIL × (VD + VIN) Table 1. RCS Values for Various LED Currents For VCS(MAX) and VCS(MIN), refer to the Electrical Characteristic table. September 2010 where: VD is Schottky diode forward drop. VLED is total LEDs voltage drop. VIN is input voltage. ILED is average LED current. 10 M9999-091710-A Micrel, Inc. MIC3202 Inductor According to the above equation, choose the inductor to make the operating frequency no higher than 1.0MHz. Tables 2, 3, and 4 give a reference inductor value and corresponding frequency for a given LED current. For space-sensitive applications, smaller inductor with higher switching frequency could be used but the efficiency of the regular will be reduced. RCS (Ω) ILED (A) L (µH) FSW (kHz) 1.33 0.15 220 474 0.56 0.35 100 439 0.4 0.5 68 461 0.28 0.7 47 467 0.2 1.0 33 475 Table 2. Inductor for VIN = 12V, 1 LED RCS (Ω) ILED (A) L (µH) FSW (kHz) 1.33 0.15 470 474 0.56 0.35 220 426 0.4 0.5 150 447 0.28 0.7 100 470 0.2 1.0 68 493 where: IL is inductor average current. Select an inductor with saturation current rating at least 30% higher than the peak current. Free-Wheeling Diode The free-wheeling diode should have the reverse voltage rating to accommodate the maximum input voltage. The forward voltage drop should be small to get the lowest conduction dissipation for high efficiency. The forward current rating has to be at least equal to LED current. A Schottky diode is recommended for highest efficiency. Input Capacitor The ceramic input capacitor is selected by voltage rating and ripple current rating. To determine the input current ripple rating, the RMS value of the input capacitor can be found by: ICIN(RMS) = ILED × D × (1 - D) The power loss in the input capacitor is: 2 PLOSS(CIN) = I Table 3. Inductor for VIN = 24V, 4 LEDs RCS (Ω) ILED (A) L (µH) FSW (kHz) 1.33 0.15 470 495 0.56 0.35 220 446 0.4 0.5 150 467 0.28 0.7 100 490 0.2 1.0 68 515 Table 4. Inductor for VIN = 36V, 8 LEDs Given an inductor value, the size of the inductor can be determined by its RMS and peak current rating. VCS(MAX ) - VCS(MIN) ΔIL = 2× = 0.18 IL VCS(MAX ) + VCS(MIN) IL(RMS ) = IL2 + IL(PK ) = IL + September 2010 1 2 ΔI ≈ I 12 L L 1 ΔI = 1.09IL 2 L CIN(RMS) × CIN ESR The input capacitor current rating can be considered as ILED/2 under the worst condition D = 50%. LED Ripple Current The LED current is the same as inductor current. If LED ripple current needs to be reduced then place a 4.7µF/50V ceramic capacitor across LED. Frequency Dithering The MIC3202 is designed to reduce EMI by dithering the switching frequency ±12% in order to spread the noise spectrum over a wider range. This lowers the EMI noise peaks generated by the switching regulator. Switching regulators generate noise by their nature and they are the main EMI source to interference with nearby circuits. If the switching frequency of a regulator is modulated via frequency dithering, the energy of the EMI is spread among many frequencies instead of concentrated at fundamental switching frequency and its harmonics. The MIC3202 modulates the VCS(MAX) with amplitude ±6mV by a pseudo random generator to generate the ±12% of the switching frequency dithering to reduce the EMI noise peaks. 11 M9999-091710-A Micrel, Inc. MIC3202 PCB Layout Guidelines Warning!!! To minimize EMI and output noise, follow these layout recommendations. PCB Layout is critical to achieve reliable, stable and efficient performance. A ground plane is required to control EMI and minimize the inductance in power, signal and return paths. The following guidelines should be followed to insure proper operation of the MIC3202 regulator. IC Use thick traces to route the input and output power lines. Signal and power grounds should be kept separate and connected at only one location. Input Capacitor Place the input capacitors on the same side of the board and as close to the IC as possible. Keep both the VIN and PGND traces as short as possible. Place several vias to the ground plane close to the input capacitor ground terminal, but not between the input capacitors and IC pins. Use either X7R or X5R dielectric input capacitors. Do not use Y5V or Z5U type capacitors. Do not replace the ceramic input capacitor with any other type of capacitor. Any type of capacitor can be placed in parallel with the input capacitor. If a Tantalum input capacitor is placed in parallel with the input capacitor, it must be recommended for switching regulator applications and the operating voltage must be derated by 50%. In “Hot-Plug” applications, a Tantalum or Electrolytic bypass capacitor must be placed in parallel to ceramic capacitor to limit the over-voltage spike seen on the input supply with power is suddenly applied. In this case an additional Tantalum or Electrolytic bypass input capacitor of 22µF or higher is required at the input power connection if necessary. Output Capacitor If LED ripple current needs to be reduced then place a 4.7µF/50V capacitor across LED. The capacitor must be placed as close to the LED as possible. Diode Place the Schottky diode on the same side of the board as the IC and input capacitor. The connection from the Schottky diode’s Anode to the switching node must be as short as possible. The diode’s Cathode connection to the RCS must be keep as short as possible. RC Snubber Place the RC snubber on the same side of the board and as close to the Schottky diode as possible. Also the snubber closest to LX pin and PGND pin. RCS (Current-Sense Resistor) Make a Kelvin connection to the VIN and CS pins respectively for current sensing. Trace Routing Recommendation Keep the power traces as short and wide as possible. One current flowing loop is during the internal MOSFET ON time, the traces connecting the input capacitor CIN, RCS, LEDs, Inductor, the LX pin, PGND and back to CIN. The other current flowing loop is during the internal MOSFET OFF time, the traces connecting RCS, LED, inductor, free wheeling diode and back to RCS. These two loop areas should kept as small as possible to minimize the noise interference, Keep all analog signal traces away from the switching node and its connecting traces. Inductor Keep the inductor connection to the switch node (LX Pin) short. Do not route any digital lines underneath or close to the inductor. To minimize noise, place a ground plane underneath the inductor. September 2010 12 M9999-091710-A Micrel, Inc. MIC3202 Ripple Measurements To properly measure ripple on either input or output of a switching regulator, a proper ring in tip measurement is required. Standard oscilloscope probes come with a grounding clip, or a long wire with an alligator clip. Unfortunately, for high-frequency measurements, this ground clip can pick-up high-frequency noise and erroneously inject it into the measured output ripple. The standard evaluation board accommodates a home made version by providing probe points for both the input and output supplies and their respective grounds. This requires the removing of the oscilloscope probe sheath and ground clip from a standard oscilloscope probe and wrapping a non-shielded bus wire around the oscilloscope probe. If there does not happen to be any non-shielded bus wire immediately available, the leads from axial resistors will work. By maintaining the shortest possible ground lengths on the oscilloscope probe, true ripple measurements can be obtained. September 2010 Figure 2. Low-Noise Measurement 13 M9999-091710-A Micrel, Inc. MIC3202 Evaluation Board Schematic Figure 3. MIC3202 Application Circuit (R9 is for test purposes only) September 2010 14 M9999-091710-A Micrel, Inc. MIC3202 Bill of Materials Item C1, C2, C8 Part Number 12105C475KAZ2A GRM32ER71H475KA88L 08053D105KAT2A C3, C9 C4, C7 GRM21BR71E105KA99L D1 AVX (2) Murata AVX(1) Murata (3) 06035C271KAT2A AVX(1) GRM188R71H104KA93D (2) Murata 4.7µF/50V, Ceramic Capacitor, X7R, Size 1210 2 1µF/25V, Ceramic Capacitor, X5R, Size 0805 1 1µF/25V, Ceramic Capacitor, X7R, Size 0805 1 270pF/50V, Ceramic Capacitor NPO, Size 0603 2 0.1µF/50V, Ceramic Capacitor, X7R, Size 0603 2 60V, 2A, SMA, Schottky Diode 1 AVX(1) Murata(2) C1608X7R1H104K TDK(3) SS24-TP MCC(4) SS24 Qty. (2) TDK GRM188R71H271KA01D Description (1) C2012X7R1E105K 06035C104MAT C5, C6 Manufacturer Fairchild(5) D2, D3 B0530WS-TP MCC(4) 30V, 200mA, Schottky diode, SOD-323 2 L1 SLF10145T-470M1R4 TDK(3) 47µH, 1.4A, SMT, Power Inductor 1 R1 CSR 1/2 0.2 1% I 0.2Ω Resistor, 1/2W, 1%, Size 1206 1 R2, R3 CRCW06031003FKEA Vishay(8) 100kΩ Resistor, 1%, Size 0603 2 R4 CRCW08052R20FKEA (8) Vishay 2.2Ω Resistor, 1%, Size 0805 1 R5 CRCW080510R0FKEA Vishay(8) 10Ω Resistor, 1%, Size 0805 1 R6 CRCW060310K0FKEA Vishay(8) 10kΩ Resistor, 1%, Size 0603 1 R7, R8 CRCW06030000FKEA (8) Vishay 0Ω Resistor, 1%, Size 0603 2 R9 CRCW060349R9FKEA Vishay(8) 49.9Ω Resistor, 1%, Size 0603 1 RV1 U1 U2 3386P-1-104TLF MIC3202YM MIC1557YM5 Stackpole Electronics, Inc(7) (9) POT 100kΩ 3/8" SQ CERM SL ST 1 Micrel, Inc. (10) High Brightness LED Driver with High-Side Current Sense 1 Micrel, Inc. (10) RC Time/Oscillator (SOT-23-5) 1 Bourns Notes: 1. AVX: www.avx.com. 2. Murata: www.murata.com. 3. TDK: www.tdk.com. 4. MCC: www.mccsemi.com. 5. Fairchild: www.fairchildsemi.com. 6. Diodes Inc. : www.diodes.com. 7. Stackpole Electronics: www.seielect.com. 8. Vishay: www.vishay.com. 9. Bourns Inc : www.bourns.com. 10. Micrel, Inc.: www.micrel.com. September 2010 15 M9999-091710-A Micrel, Inc. MIC3202 PCB Layout Recommendation Top Assembly Top Layer September 2010 16 M9999-091710-A Micrel, Inc. MIC3202 PCB Layout Recommendation (Continued) Bottom Layer September 2010 17 M9999-091710-A Micrel, Inc. MIC3202 Package Information 8-Pin ePAD SOIC (ME) September 2010 18 M9999-091710-A Micrel, Inc. MIC3202 Recommended Landing Pattern 8-Pin ePAD SOIC (ME) 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 Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right 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. © 2010 Micrel, Incorporated. September 2010 19 M9999-091710-A