SMPS Capacitors SMPS Capacitors Performance Foreword Output Filter Capacitor High speed switch mode power supplies place high demands on the capacitors used in the input or output filters of Resonant DC-DC or Pulse Modulated DC-DC converters. Olean Advanced Products, a division of AVX Corporation has developed two multilayer ceramic (MLC) capacitor series (SM and SK) for these switcher applications. These capacitors have been extensively tested and characterized and found to have almost ideal performances to meet the stringent requirements of these applications. The output from the switching circuit of a Switcher consists of current on and off. From an elevated DC reference, this current is an AC ripple additive on the DC. In order to smooth this ripple effect, a filter circuit (usually inductive input) is built to allow a storage of energy to take place during the rising ripple portion and to allow a discharge of energy during the falling ripple portion. The ESR and ESL of the capacitor contribute to the net ripple effect. The output filter capacitor is chosen for ESR, and with previous types of capacitors, multiples were used in an attempt to lower the net ESR. The MLC offers ESRs well below the minimum allowable to lower noise levels, thus eliminating the need for multiple units. Input Filter Capacitor The Input Filter capacitor is required to perform two functions: To supply an unrestricted burst of current to the power supply switch circuitry and to not only do it without generating any noise, but to help suppress noise generated in the switch circuitry. It is, in effect, a very large decoupling capacitor. It must have very low ESL, capabilities for very high dv/dt, as well as di/dt and it must have a very low ESR to eliminate power loss. The distance from the primary DC source, as well as the type of capacitor used in this source (usually electrolytics), presents a very high inductance to the input of the Switcher. The MLC input capacitor, with its excellent ESL and ESR characteristics, is located physically close to the switch circuitry. Repetitive peak currents, inherent with the Switcher design, require a high ripple capability, as well as high surge capability for transients, both induced and conducted from other sources. MLCs have both these capabilities. Other MLC Capacitors for SMPS Applications Advanced Products also manufactures line filter, coupling, decoupling, resonant and snubber capacitors for SMPS applications. Contact OLEAN ADVANCED PRODUCTS for Application Specific S.M.P.S. capacitor requirements (716-372-6611). 4 SMPS Capacitors SM & SK Series/SMPS Capacitors Capacitor Performance SMPS Design Information (SM and SK Series) Absolute Maximum Output Capacitance Absolute Maximum Capacitance ESL Assuming no ESR - Capacitive Induced Ripple Assuming no ESL and no ESR 2 MHz 25 25 SM Series 20 Load Current - Amps Load Current - Amps 1 MHz 15 500 KHz 10 5 250 KHz 0 SK Series 20 15 50 mv Noise Due to ESL 10 250 Khz 500 KHz 5 1 MHz 2 MHz 0 0 5 10 15 Maximum Output Filter Capacitance ( mF) 20 0 5 10 15 Maximum Output Filter Capacitance ESL (nH) 20 Absolute Maximum Capacitance ESR Assuming no ESL - Capacitive Induced Ripple 50 mv Noise Due to ESR 20 15 5 SK Series 10 SM Series Load Current - Amps 25 0 0 10 20 30 40 Maximum Output Filter Capacitance ESR (mOhm) Capacitance as Measured from dv/dt Slope 200 mA/nS Current Pulse Measurement starts after Inductive Ring Decay 16 14 AI Electrolytic 15 m F 12 Capacitance ( mF) MLC SM02 10 m F 10 Wet Ta 10 m F 8 Solid Ta 5.6 m F 6 4 MLC SM04 4.7 m F 2 0 10 -9 10 -8 10 -7 Time (Seconds) 5 10 -6 10 -5 SMPS Capacitors Capacitor Performance AC Ripple Capability (SM_, SK_, SV_ and High Voltage Chip Capacitors) CALCI program will provide answers to most of the design engineers' questions on critical parameters for their specific applications: Due to the wide range of product offering in this catalog, the AC ripple capabilities for switch mode power supply capacitors (SM_ & SK_) and high voltage capacitors (SV_ & SMD) are provided in the form of IBM compatible software package called CALCI. The 3.5" diskette with a compiled, executable file can be obtained by filling out and mailing the form enclosed in this catalog. * Equivalent Series Resistance - function of frequency and temperature * Equivalent Series Inductance - function of design * Self Resonant Frequency f = 1/ (2 x L x C) I * Thermal Characteristics - function of design * AC Ripple Capabilities - function of frequency, temperature and design TYPICAL ESR -vs- Frequency MAXIMUM RMS CURRENT FOR 50 WVDC, SM - Z5U @ 100 KHz & 258C Ambient ASSUMING MAX. CAP. FOR SINGLE CHIP CONSTRUCTION FOR SM04 STYLE CAPACITORS 4.7uF 9uF 1uF 50 10.000 45 40 100 KHz ARMS ESR (Ohms) 1.000 0.100 35 30 25 20 15 0.010 10 5 0.001 1.0 10.0 100.0 Frequency (kHz) 0 1000.0 30.9 SM01 16.0 SM03 STYLE 6.0 SM04 3.3 SM05 40.1 SM06 MAXIMUM RMS CURRENT FOR 25 WVDC, SK - Z5U MAXIMUM RMS CURRENT FOR 50 WVDC, SM - X7R @ 100 KHz & 258C Ambient ASSUMING MAX. CAP. FOR EACH STYLE @ 100 KHz & 258C Ambient ASSUMING MAX. CAP. FOR SINGLE CHIP CONSTRUCTION 50 20 45 18 40 16 35 14 100 KHz ARMS 100 KHz ARMS 29.3 SM02 30 25 20 12 10 8 6 15 10 4 5 2 0 0 28.6 SM01 29.1 SM02 15.4 6.3 SM03 SM04 STYLE 3.5 SM05 1.4 SK01 42.7 SM06 6 1.9 SK02 3.2 SK03 4.6 6.6 SK04 SK05 STYLE 11.1 SK06 12.1 SK07 17.8 SK08 SMPS Capacitors SK Series/SMPS Capacitors Product Offering - C0G, X7R and Z5U Olean Advanced Products' SK series are conformally coated MLC capacitors for input or output filtering in switch mode power supplies. They are specially processed to handle high currents and are low enough in cost for commercial SMPS application. How to Order: SK 01 3 E Style Size See chart below Voltage 25V = 3 50V = 5 100V = 1 200V = 2 500V = 7 Temperature Coefficient Z5U = E X7R = C C0G = A 125 Z Capacitance Code (2 significant digits + no. of zeros) 22 nF = 223 220 nF = 224 1 F = 105 100 F = 107 Capacitance Tolerance Z5U: Z = +80, -20% P = GMV X7R: K = 10% M = 20% Z = +80, -20% C0G: J = 5% K = 10% M = 20% Maximum Capacitance Values (C0G), Fd Style 50 WVDC A A Failure Leads Rate A = Does not A = Does apply not apply Maximum Capacitance Values (X7R), Fd 100 WVDC 200 WVDC 500 WVDC Style 50 WVDC .010 .0056 .0018 SK01 0.27 0.15 .022 .0068 SK03 1.0 0.56 0.39 0.15 .047 .015 SK04 2.2 1.2 0.68 0.27 .068 .022 SK05 3.3 1.8 1.2 0.39 .22 .068 SK06 10 5.6 3.9 1.2 .47 .27 .082 SK07 14 8.2 4.7 1.8 .82 .47 .15 SK08 22 15 8.2 3.3 SK01 .012 SK03 .047 .039 SK04 .10 .082 SK05 .15 .12 SK06 .47 .39 SK07 .56 SK08 1.10 100 WVDC Maximum Capacitance Values (Z5U), Fd Style 25 WVDC SK01 1.2 50 WVDC 0.82 100 WVDC 0.47 200 WVDC 0.33 SK03 5.6 3.30 2.20 1.50 SK04 10.0 8.20 4.70 3.90 SK05 18.0 10.00 6.80 4.70 SK06 47.0 39.00 22.00 15.00 SK07 68.0 47.00 27.00 18.00 SK08 120.0 100.00 47.00 33.00 14 200 WVDC 0.082 500 WVDC 0.033 SK Series/SMPS Capacitors Product Offering - C0G, X7R and Z5U L L H T H M LD M LL LD LL LS LS SK01 SK03 - SK08 DIMENSION CHART Style L (max.) H (max.) T (max.) LS (nom.) LD (nom.) SK01 0.200 0.200 0.200 0.200 0.020 SK03 0.300 0.300 0.200 0.200 0.020 SK04 0.400 0.400 0.200 0.200 0.020 SK05 0.500 0.500 0.200 0.400 0.025 SK06 0.870 0.600 0.200 0.790 0.032 SK07 1.100 0.600 0.200 0.980 0.032 SK08 1.100 0.600 0.350 0.980 0.032 L -= Length H = Height T = Thickness M = Meniscus (0.060 max.) 15 LS = Lead Spacing (Nominal 0.031) LL = Lead Length (2" max./1" min.) LD = Lead Diameter (Nominal 0.002)