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MIC22600 1mhz, 6a integrated switch synchronous buck regulator not recommended for new designs see mic22705 95131 ? us 408 ramp control is a trademark of micrel, inc. mlf and micro leadframe are registered trademarks of amkor tec micrel inc. ? 2180 fortune drive ? san jose, ca hnology, inc. a ? tel +1 ( 408 ) 944-0800 ? fax + 1 ( ) 474-1000 ? http://www.micrel.com june 2011 m9999-062411-d general description the micrel MIC22600 is a high-efficiency, 6a, integrated switch, synchronous buck (step-down) regulator. the MIC22600 is optimized for highest efficiency and achieves more than 90% efficiency, while still switching at 1mhz over a broad load range with only 1h inductor and down to 47f output capacitor. the ultra-high-speed control loop keeps the output voltage within regulation even under extreme transient load swings commonly found in fpgas and low voltage asics. the output voltage can be adjusted down to 0.7v to address all low voltage power needs. the MIC22600 offers a full range of sequencing and tracking options. the en/dly pin combined with the power good/power-on-reset (pg/por) pin allows multiple outputs to be sequenced in any way during turn- on and turn-off. the rc (ramp control?) pin allows the device to be connected to another product in the mic22xxx and/or mic68xxx family, to keep the output voltages within a certain ? v on start-up. the MIC22600 is available in a 24-pin 4mm x 4mm mlf ? and thermally-enhanced 24-pin epad tssop with a junction operating range from ?40 c to +125 c. data sheets and support documentation can be found on micrel?s web site at: www.micrel.com . features ? input voltage range: 2.6v to 5.5v ? output voltage adjustable down to 0.7v ? output current up to 6a ? full sequencing and tracking ability ? power-on-reset/power good ? efficiency > 90% across a broad load range ? ultra-fast transient res ponse, easy rc compensation ? 100% maximum duty cycle ? fully-integrated mosfet switches ? micropower shutdown ? thermal-shutdown and cu rrent-limit protection ? 24-pin 4mm x 4mm mlf ? ? 24-pin epad tssop ? ?40 c to +125 c junction temperature range applications ? high power density point-of-load conversion ? servers and routers ? dvd recorders ? computing peripherals ? base stations ? fpgas, dsp and low-voltage asic power typical application MIC22600 6a 1mhz synchronous output converter sequencing & tracking note: 1. using a free-wheeling schottk y diode improves efficiency.
micrel, inc. MIC22600 june 2011 2 m9999-062411-d ordering information part number voltage junction temperature range package lead finish MIC22600yml adjustable ?40 to +125c 24-pin 4mm x 4mm mlf ? pb-free MIC22600ytse adjustable ?40 to +125c 24-pin epad tssop pb-free note: mlf ? is a green rohs-compliant package. lead fini sh is nipdau. mold compound is halogen free. pin configuration pvin en/dly delay rc por/pg pvin pvin svin sgnd comp fb pvin sw sw sw pgnd sw pgnd sw sw sw pgnd sw pgnd ep 24-pin 4mm x 4mm mlf (ml) 24-pin epad tssop
micrel, inc. MIC22600 june 2011 3 m9999-062411-d pin description pin number mlf-24 pin number tssop-24 pin name description 1, 6, 13, 18 3, 10, 15, 22 pvin power supply voltage (input): r equires bypass capacitor to gnd. 17 2 svin signal power supply voltage (input ): requires bypass capacitor to gnd. 2 11 en/dly en/dly (input): when this pin is pulled higher than the enable threshold, the part will start up. below this voltage t he device is in its low quiescent current mode. the pin has a 1a current source charging it to vin. by adding a capacitor to this pin a delay may easily be generated. the enable function will not operate with an input voltage lowe r than the min specified voltage. 4 13 rc ramp control: capacitor to ground from this pin determines slew rate of output voltage during start-up. this can be used for tracking capability as well as soft start. rc pin cannot be left floating. use a minimum capacitor value of 220pf or larger. 14 23 fb feedback: input to the error amplifier, connect to the external resistor divider network to set the output voltage. 15 24 comp compensation pin (input): place a rc network to gnd to compensate the device, see applications section. 5 14 por/pg power on reset (output): open-drain output device indicates when the output is out of regulation and is active after the delay set by the delay pin. 7, 12, 19, 24 4, 9, 16, 21 pg nd power ground (signal): ground 16 1 sgnd signal ground (signal): ground 3 12 delay delay (input): capacitor to ground sets internal delay timer. timer delays power-on reset (por) output at turn -on and ramp down at turn-off. 8, 9, 10, 11, 20, 21, 22, 23 5, 6, 7, 8, 17, 18 19, 20 sw switch (output): internal power mosfet output switches. ep ep gnd exposed pad (power): must make a fu ll connection to a gnd plane for full output power to be realized.
micrel, inc. MIC22600 june 2011 4 m9999-062411-d absolute maximum ratings (1) supply voltage (pvin, svin)............................ ?0.3v to 6v output switch voltage (sw) ............................. ?0.3v to 6v output switch current (i sw ).......................internally limited logic input voltage (en, por, delay) ........... ?0.3v to v in control voltage (rc, co mp, fb) ..................... ?0.3v to v in lead temperature (solde ring 10sec. ) ........................ 260c storage temperature (t s ) .........................?65c to +150c esd rating (3) .................................................................. 2kv operating ratings (2) supply voltage (v in )......................................... 2.6v to 5.5v junction temperature (t j ) ..................?40c t j +125c thermal resistance 4x4 mlf-24 ( jc ) ...............................................14c/w 4x4 mlf-24 ( ja ) ...............................................40c/w 24-pin epad tssop ( jc )...............................12.9c/w 24-pin epad tssop ( ja ) ...............................32.2c/w electrical characteristics (4) t a = 25c with v in = v en = 3.3v; v out = 1.8v, unless otherwise specified. bold values indicate ?40c < t j < +125c. parameter condition min. typ. max. units supply voltage range 2.6 5.5 v v in turn-on voltage threshold v in rising 2.4 2.5 2.6 v uvlo hysteresis 280 mv quiescent current, pwm mode v en 1.34v; v fb = 0.9v (not switching) 850 1300 a shutdown current v en = 0v 5 10 a feedback voltage 1% 2% (over temperature) 0.693 0.686 0.7 0.707 0.714 v fb pin input current 1 100 na current limit in pwm mode v fb = 0.5*v nom 6.5 9 11.5 a output voltage line regulation v out 1.8v, v in = 2.6 to 5.5v, i load = 100ma 0.2 % output voltage load regulation 100ma < i load < 6000ma, v in = 3.3v 0.2 % maximum duty cycle v fb 0.5v 100 % switch on-resistance pfet switch on-resistance nfet i sw = 1000ma; v fb =0.5v i sw = 1000ma; v fb =0.9v 0.03 0.025 ? oscillator frequency 0.8 1 1.2 mhz en/dly threshold voltage 1.14 1.24 1.34 v en/dly source current v in = 2.6 to v in = 5.5v 0.7 1 1.3 a rc pin i ramp ramp control current 0.7 1 1.3 a power-on-reset i pg(leak) v porh = 5.5v; por = high 1 2 a power-on-reset v pg(lo) output logic-low voltage (undervoltage condition), i por = 5ma 130 mv threshold, % of v out below nominal 7.5 10 12.5 % power-on-reset v pg hysteresis 2 % over-temperature shutdown 160 c over-temperature shutdown hysteresis 20 c notes: 1. exceeding the absolute maximum rating may damage the device. 2. the device is not guaranteed to function outside its operating rating. 3. devices are esd sensitive. handling precautions recommended. 4. specification for packaged product only.
micrel, inc. MIC22600 typical characteristics june 2011 5 m9999-062411-d
micrel, inc. MIC22600 typical characteristics (continued) june 2011 6 m9999-062411-d
micrel, inc. MIC22600 june 2011 7 m9999-062411-d functional characteristics start-up/shutdown ( c rc = 10nf ) enable vo ltage (2mv/div) outpu t curren t (2a/div) time (2ms/div) ramp contro l voltage (500mv/div) v in = 3v v o = 1.8v r o outpu t voltage (1v/div) transient response t voltage (500mv/div) outpu t curren t (2a/div) inpu time (200s/div) outpu t voltage (50mv/div) v in = 3v v o = 1.8v i o = 0.6a to 6a transient response outpu t curren t (2a/div) input voltage (1v/div) time (200s/div) high dc operation switch vo ltage (2v/div) time (200ns/div) v in = 5v v o = 1.8v i o = 0.6a to 6a outpu t voltage (50mv/div) outpu t voltage (10mv/div) v in = 5v i o = 1a output noise & ripple switch vo ltage (2v/div) time (400ns/div) start-up (c rc = 0nf) enable vo ltage (1v/div) outpu t curren t (2a/div) time (20s/div) ramp contro l voltage (500mv/div) v in = 5v v o = 3.3v i o = 6a outpu t voltage (10mv/div) outpu t voltage (500mv/div) v in = 3v v o = 1v i o = 6a
micrel, inc. MIC22600 june 2011 8 m9999-062411-d functional characteristics (continued) start-up into short enable vo ltage (2v/div) switch vo ltage (2v/div) time (20s/div) v in = 3v input curren t (2a/div) outpu t voltage (100mv/div) current limit behavior outpu t voltage (500mv/div) outpu t curren t (2a/div) time (200s/div) inpu t voltage (500mv/div) v in = 3v v o = 1.8v i oset = 12a
micrel, inc. MIC22600 june 2011 9 m9999-062411-d typical circuits and waveforms sequencing circuit and waveform tracking circuit and waveform
micrel, inc. MIC22600 june 2011 10 m9999-062411-d functional diagram figure 1. MIC22600 block diagram
micrel, inc. MIC22600 june 2011 11 m9999-062411-d functional description pvin, svin pvin is the input supply to the internal 30m ? p-channel power mosfet. this should be connected externally to the svin pin. the supply voltage range is from 2.6v to 5.5v. a 10f ceramic is recommended for bypassing each pvin supply. en/dly this pin is internally fed with a 1a current source from vin. a delayed turn on is implemented by adding a capacitor to this pin. the delay is proportional to the capacitor value. the internal circuits are held off until en/dly reaches the enable threshold of 1.24v. rc rc allows the slew rate of the output voltage to be programmed by the addition of a capacitor from rc to ground. rc is internally fed with a 1a current source and vout slew rate is proportional to the capacitor and the 1a source. rc pin cannot be left floating. use a minimum capacitor value of 220pf or larger. delay adding a capacitor to this pin allows the delay of the por signal. when vout reaches 90% of its nominal voltage, the delay pin current source (1a) starts to charge the external capacitor. at 1.24v , por is asserted high. comp the MIC22600 uses an internal compensation network containing a fixed frequency zero (phase lead response) and pole (phase lag response) which allows the external compensation network to be mu ch simplified for stability. the addition of a single capacitor and resistor will add the necessary pole and zero for voltage mode loop stability using low value, lo w esr ceramic capacitors. fb the feedback pin provides the control path to control the output. a resistor divider connecting the feedback to the output is used to adjust the desired output voltage. refer to the feedback section in t he ?applications information? for more detail. por this is an open drain output. a 47k resistor can be used for a pull up to this pin. por is asserted high when output voltage reaches 90% of nominal set voltage and after the delay set by c delay . por is asserted low without delay when enable is set low or when the output goes below the -10% threshold. for a power good (pg) function, the delay can be set to a minimum. this can be done by removing the delay capacitor. sw this is the connection to the source of the internal p- channel mosfet and drain of the n-channel mosfet. this is a high frequency high power connection; therefore traces should be k ept as short and as wide as practical. sgnd internal signal ground for all low power sections. pgnd internal ground connection to the source of the internal n-channel mosfets.
micrel, inc. MIC22600 june 2011 12 m9999-062411-d application information the MIC22600 is a 6a synchr onous step down regulator ic with a fixed 1 mhz, voltage mode pwm control scheme. the other features include tracking and sequencing control for controlling multiple output power systems, power on reset. component selection input capacitor a minimum 10f ceramic is recommended on each of the pvin pins for bypassing. x5r or x7r dielectrics are recommended for the input capacitor. y5v dielectrics is not recommended. output capacitor the MIC22600 was designed spec ifically for the use of ceramic output capacitors and 22f is optimum output capacitor. 22f can be increased to 100f to improve transient performance. since the MIC22600 is a voltage mode controller, the control loop relies on the inductor and output capacitor for compensation. for this reason, do not use excessively large output capacitors. the output capacitor requires either an x7r or x5r dielectric. y5v and z5u dielectric capacitors, aside from the undesirable effect of their wide variation in capacitance over temperature, become resistive at high frequencies. using y5v or z5u capacitors can cause instability in the MIC22600. inductor selection inductor selection is determined by the following (not necessarily in the order of importance): ? inductance ? rated current value ? size requirements ? dc resistance (dcr) the MIC22600 is designed to use a 0.47h to 4.7h inductor. 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 40c temperature rise or a 10% loss in inductance. ensure the inductor selected can handle the maximum operating current. when saturation current is specified, make sure that there is enough margin that the peak current will not saturate the inductor. the ripple can add as much as 1.2a to the output current level. the rms rating should be chosen to be equal or greater than the current limit of the MIC22600 to prevent overheating in a fault condition. for best electrical performance, the inductor should be placed very close to the sw nodes of the ic. it is important to test all operating limits before settling on the final inductor choice. the size requirements refer to the area and height requirements that are necessary to fit a particular design. please refer to the inductor dimensions on their datasheet. dcr is inversely proportional to size and can represent a significant efficiency loss. refer to the ?efficiency considerations? below for a more detailed description. en/dly capacitor en/dly sources 1a out of the ic to allow a startup delay to be implemented. the delay time is simply the time it takes 1a to charge cdly to 1.25v. therefore: 6 dly dly 1.10 c1.24 t ? = efficiency considerations efficiency is defined as the amount of useful output power, divided by the amount of power consumed. efficiency % = 100 iv iv inin out out ? ? ? ? ? ? ? ? maintaining high efficiency serves two purposes. it decreases power dissipation in the power supply, reducing the need for heat sinks and thermal design considerations and it decreas es consumption of current for battery powered applicat ions. reduced current drawn from a battery increases the devices operating time, particularly in hand held devices. there are mainly two loss terms in switching converters: conduction losses and switching losses. conduction losses are simply the power losses due to vi or i 2 r. for example, power is dissipat ed in the high side switch during the on cycle. the power loss is equal to the high side mosfet rds (on) multiplied by the rms switch current squared (i sw 2 ). during the off cycle, the low side n-channel mosfet conducts, also dissipating power. similarly, the inductor?s dcr and capacitor?s esr also contribute to the i 2 r losses. device operating current also reduces efficiency by the product of the quiescent (operating) current and the supply voltage. the power consumed at 1mhz frequency and power loss due to switching transitions add up to switching losses. a free wheeling schottky diode is recommended to use in parallel with synchronous n-mosfet to improve the efficiency.
micrel, inc. MIC22600 june 2011 13 m9999-062411-d figure 2 shows an efficiency curve. the portion, from 0a to 1a, efficiency losses are dominated by quiescent current losses, gate drive and transition losses. in this case, lower supply voltages yield greater efficiency in that they require less current to drive the mosfets and have reduced input power consumption. 50 55 60 65 70 75 80 85 90 95 0 200 400 600 800 output current (ma) vs. inductance efficiency l = 1h figure 2. efficiency curve the region, 1a to 6a, efficiency loss is dominated by mosfet rds (on) and inductor dc losses. higher input supply voltages will increase the gate-to-source voltage on the internal mosfets, reducing the internal rds (on) . this improves efficiency by decreasing conduction loss in the device but the inductor dcr loss is inherent to the device. so inductor selection becomes increasingly critical in efficiency calculations. as the inductors are reduced in size, the dc resistance (dcr) can become quite significant. the dcr losses can be calculated as follows: l pd = i out 2 dcr from that, the loss in efficiency due to inductor resistance can be calculated as follows: efficiency loss = () 100 liv iv 1 pd out out out out ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? + ? l = 4.7h figure 3. efficiency vs. inductance efficiency loss due to dcr is minimal at light loads and gains significance as the load is increased. inductor selection becomes a trade-off between efficiency and size in this case. alternatively, under lighter loads, the ripple current becomes a significant factor. when light load efficiencies become more critical, a larger inductor value maybe desired. larger inductance reduces the peak-to-peak inductor ripple current, which minimize losses. the graph in figure 3 illustrates the effects of inductance value at light load. compensation the MIC22600 has a combination of internal and external stability compensation to simplify the circuit for small, high efficiency designs. in such designs, voltage mode conversion is often the optimum solution. voltage mode is achieved by creating an internal 1mhz ramp signal and using the output of the error amplifier to modulate the pulse width of the switch node, thereby maintaining output voltage regulation. with a typical gain bandwidth of 100-200khz, the MIC22600 is capable of extremely fast transient responses. the MIC22600 is designed to be stable with a typical application using a 1h inductor and a 47f ceramic (x5r) output capacitor. these values can be varied dependant upon the tradeoff between size, cost and efficiency, keeping the lc natural frequency ( c ? l 2 1 ) ideally less than 26 khz to ensure stability can be achieved. the minimum recommended inductor value is 0.47h and minimum recommended output capacitor value is 22f. with a larger inductor, there is a reduced peak-to-peak current which yields a greater efficiency at lighter loads. a larger output capacitor will improve transient response by providing a larger hold up reservoir of energy to the output.
micrel, inc. MIC22600 june 2011 14 m9999-062411-d the integration of one pole-zero pair within the control loop greatly simplifies compensation. the optimum values for c comp (in series with a 20k resistor) are shown below. c l 22-47f 47f- 100f 100f- 470f 0.47h 0*-10pf 22pf 33pf 1h 0 ? -15pf 15-22pf 33pf 2.2h 15-33pf 33-47pf 100-220pf * vout > 1.2v, ? vout > 1v table1. compensation capacitor selection feedback the MIC22600 provides a feedback pin to adjust the output voltage to the desired level. this pin connects internally to an error amplifier. the error amplifier then compares the voltage at the feedback to the internal 0.7v reference voltage and adjusts the output voltage to maintain regulation. the resistor divider network for a desired v out is given by: ? ? ? ? ? ? ? ? ? = 1 v v r1 r2 ref out where v ref is 0.7v and v out is the desired output voltage. a 10k ? or lower resistor value from the output to the feedback is reco mmended since large feedback resistor values increase the impedance at the feedback pin, making the feedback node more susceptible to noise pick-up. a small capacitor (50pf ? 100pf) across the lower resistor can reduce noise pick-up by providing a low impedance path to ground. pwm operation the MIC22600 is a voltage mode, pulse width modulation (pwm) controller. by controlling the duty cycle, a regulated dc output voltage is achieved. as load or supply voltage changes, so does the duty cycle to maintain a constant output voltage. in cases where the input supply runs into a dropout condition, the MIC22600 will run at 100% duty cycle. the MIC22600 provides constant switching at 1mhz with synchronous internal mosfets. the internal mosfets include a high-side p-channel mosfet from the input supply to the switch pin and an n-channel mosfet from the switch pin-to-ground. since the low-side n- channel mosfet provides the current during the off cycle, a freewheeling schottky diode from the switch node-to-ground is not required. pwm control provides fixed-frequency operation. by maintaining a constant switching frequency, predictable fundamental and harmonic frequencies are achieved. sequencing and tracking the MIC22600 provides additional pins to provide up/down sequencing and tracking capability for connecting multiple voltage regulators together. en/dly pin the en pin contains a trimmed, 1a current source which can be used with a capacitor to implement a fixed desired delay in some sequenced power systems. the threshold level for power on is 1.24v with a hysteresis of 20mv. delay pin the delay pin also has a 1a trimmed current source and a 1a current sink which acts with an external capacitor to delay the operation of the power on reset (por) output. this can be used also in sequencing outputs in a sequenced system, but with the addition of a conditional delay between supplies; allowing a first up, last down power sequence. after en is driven high, v out will start to rise (rate determined by rc capacitor). as the fb voltage goes above 90% of its nominal set voltage, delay begins to rise as the 1a source charges the external capacitor. when the threshold of 1.24v is crossed, por is asserted high and delay continues to charge to a voltage sv in . when fb falls below 90% of nominal, por is asserted low immediately. however, if en is driven low, por will fall immediately to the low state and delay will begin to fall as the external capacitor is discharged by the 1a current sink. when the threshold of ((v tp +1.24v)-1.24v) is crossed (v tp is the internal voltage clamp, v tp -=0.9v), v out will begin to fall at a rate determined by the rc capacitor. as the voltage change in both cases is 1.24v, both rising and falling delays are matched at 6 dly por 1.10 c1.24 ? = t rc pin the rc pin provides a trimmed 1a current source/sink similar to the delay pin for accurate ramp up (soft start) and ramp down control. this allows the MIC22600 to be used in systems requiring voltage tracking or ratio- metric voltage tracking at startup. there are two ways of using the rc pin: 1. externally driven from a voltage source 2. externally attached capacitor sets output ramp up/down rate
micrel, inc. MIC22600 june 2011 15 m9999-062411-d in the first case, driving rc with a voltage from 0v to v ref programs the output voltage between 0 and 100% of the nominal set voltage. in the second case, the external capacitor sets the ramp up and ramp down time of the output voltage. the time is given by 6 10.1 7.0 ? = rc ramp c ? t where t ramp is the time from 0 to 100% nominal output voltage. rc pin cannot be left floating. use a minimum capacitor value of 220pf or larger. sequencing and tracking examples there are four distinct variations which are easily implemented using the MIC22600. the two sequencing variations are delayed and windowed. the two tracking variants are normal and ratio metric. the following diagrams illustrate methods for connecting two MIC22600?s to achieve these requirements.
micrel, inc. MIC22600 june 2011 16 m9999-062411-d sequencing: figure 4. sequencing MIC22600 circuit figure 5. window sequencing example figure 6. delayed sequencing example normal tracking: figure 7. normal tracking circuit figure 8. normal tracking example
micrel, inc. MIC22600 june 2011 17 m9999-062411-d ratio metric tracking: figure 9. ratio metric tracking circuit figure 10. ratio metric tracking example an alternative method here shows an example of a v ddq & v tt solution for a ddr memory power supply. note that por is taken from vo1 as por 2 will not go high. this is because por is set high when fb > 0.9 ? v ref . in this example, fb 2 is regulated to ? ? v ref . ddr memory vdd and vtt tracking figure 11. ddr memory tracking circuit figure 12. ddr memory tracking example
micrel, inc. MIC22600 june 2011 18 m9999-062411-d where current limit ? p diss is the power dissipated within the mlf ? package and is typically 1. 5w at 6a load. this has been calculated for a 1h inductor and details can be found in table 1 below for reference. the MIC22600 is protected against overload in two stages. the first is to limit the current in the p-channel switch; the second is by over temperature shutdown. current is limited by measuring the current through the high-side mosfet during its power stroke and immediately switching off the driver when the preset limit is exceeded. ? r ja is a combination of junction to case thermal resistance (r jc ) and case-to-ambient thermal resistance (r ca ), since thermal resistance of the solder connection from the epad to the pcb is negligible; r ca is the thermal resistance of the ground plane to ambient, so r ja = r jc + r ca . the circuit in figure 4 describes the operation of the current-limit circuit. since the actual rds on of the p- channel mosfet varies part-to-part, over temperature and with input voltage, simple ir voltage detection is not employed. instead, a smaller copy of the power mosfet (reference fet) is fed with a constant current which is a directly proportional to the factory set current limit. this sets the current limit as a current ratio and thus, is not dependant upon the rds on value. ? current limit is set to 9a nominal. variations in the scale factor k between the power pfet and the reference pfet used to generate the limit threshold account for a relatively small inaccuracy. ? t amb is the operating ambient temperature. example: the evaluation board has two copper planes contributing to an r ja of approximately 25c/w. the worst case r jc of the mlf 4x4 is 14 o c/w. r ja = r jc + r ca r ja = 14 + 25 = 39 o c/w to calculate the junction temperature for a 50c ambient: t j = t amb +p diss . r ja t j = 50 + (1.5 x 39) t j = 109c figure 13. current-limit detail this is below the maximum of 125c. thermal considerations the MIC22600 is packaged in the mlf ? 4mm x 4mm, a package that has excellent thermal performance equaling that of the larger tssop packages. this maximizes heat transfer from the junction to the exposed pad (epad) which connects to the ground plane. the size of the ground plane attached to the exposed pad determines the overall thermal resistance from the junction to the ambient air surrounding the printed circuit board. the junction temperature for a given ambient temperature can be calculated using: v in v out @6a 3 3.5 4 4.5 5 1 1.47 1.50 1. 52 1.54 1.56 1.2 1.45 1.47 1.49 1.51 1.54 1.8 1.46 1.45 1.45 1.47 1.48 2.5 1.61 1.53 1.49 1.47 1.47 3.3 ? 1.70 1.62 1.56 1.53 table 2. power dissipation (w) for 6a output t j = t amb + p diss r ja
micrel, inc. MIC22600 june 2011 19 m9999-062411-d ripple measurements to properly measure ripple on ei ther 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 fr om 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.
micrel, inc. MIC22600 june 2011 20 m9999-062411-d pcb layout guideline 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 mic22602 converter. ic ? place the ic close to the point of load (pol). ? use fat traces to route the input and output power lines. ? the exposed pad (ep) on the bottom of the ic must be connected to the ground. ? use several vias to connect the ep to the ground plane, layer 2. ? signal and power grounds should be kept separate and connected at only one location. input capacitor ? place the input capacitor next. ? place the input capacitors on the same side of the board and as close to the ic as possible. ? place a 22f/6.3v ceramic bypass capacitor next to each of the 4 pvin pins. ? keep both the vin and pgnd connections short. ? 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 used to limit the over- voltage spike seen on the input supply with power is suddenly applied. inductor ? keep the inductor connection to the switch node (sw) short. ? do not route any digital lines underneath or close to the inductor. ? keep the switch node (sw) away from the feedback (fb) pin. ? to minimize noise, place a ground plane underneath the inductor. output capacitor ? use a wide trace to connect the output capacitor ground terminal to the input capacitor ground terminal. ? phase margin will change as the output capacitor value and esr changes. contact the factory if the output capacitor is different from what is shown in the bom. ? the feedback trace should be separate from the power trace and connected as close as possible to the output capacitor. sensing a long high current load trace can degrade the dc load regulation. 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 input capacitors ground terminal must be as short as possible. ? the diode?s cathode connection to the switch node (sw) must be keep as short as possible.
micrel, inc. MIC22600 june 2011 21 m9999-062411-d MIC22600yml schematic bill of materials item part number manufacturer description qty. c2012x5r0j226m tdk (1) 08056d2226mat avx (2) c1, c2, c3, c4, c5 grm21br60j226me39l murata (3) 22f/6.3v, 0805 ceramic capacitor 5 c6 open open, 0603 ceramic capacitor 1 grm188r71h221ka01d murata (3) vj0603y221kxacw1bc vishay (4) c7 c1608x7r1h221k tdk (1) 220pf, 0603 ceramic capacitor 1 open (vj0603y102kqcw1bc) vishay (4) c8 open (grm188r71h102ka01d) murata (3) 1nf, 0603 ceramic capacitor 1 grm1555c1h390jz01d murata (3) c9 vj0402a390kxqcw1bc vishay (4) 39pf, 0402 ceramic capacitor 1 c3216x5r0j476m tdk (1) 12066d476kat avx (2) c10, c11 grm31cc80g476me19l murata (3) 47f/6v, 1206 ceramic capacitor 2 vj0402a101kxqcw1bc vishay (4) c12 grm15551h101jz01d murata (3) 100pf, 0402 ceramic capacitor 1 d1 dfls220l-7 diodes inc (5) 2a, 20v schottky diode 1 cdrh8d43np-1r2nc sumida (6) fp3-1r0-r coiltronics (7) l1 spm6530t-1r0m120 tdk (1) 1h, 6a inductor 1
micrel, inc. MIC22600 june 2011 22 m9999-062411-d bill of materials (continued) item part number manufacturer description qty. r1 crcw06031101fkeye3. vishay (4) 1.1k, 0603 resistor 1 r2 crcw04026980fkeye3. vishay (4) 698? , 0402 resistor 1 r3 crcw06034752fkeye3. vishay (4) 47.5k, 0603 resistor 1 r4 crcw04022002fkeye3. vishay (4) 20k, 0402 resistor 1 rx open open, 0603 resistor 1 q1 open sot-23 1 u1 MIC22600yml micrel (8) integrated 6a synchronous buck regulator 1 notes: 1. tdk: www.tdk.com . 2. avx: www.avx.com . 3. murata: www.murata.com . 4. vishay: www.vishay.com . 5. diodes inc.: www.diodes.com . 6. sumida: www.sumida.com . 7. coiltronics: www.mouser.com/coiltronics . 8. micrel: www.micrel.com .
micrel, inc. MIC22600 june 2011 23 m9999-062411-d pcb layout recommendations ? yml package top layer
micrel, inc. MIC22600 june 2011 24 m9999-062411-d MIC22600ytse schematic bill of materials item part number manufacturer description qty c2012x5r0j226m tdk (1) 08056d2226mat avx (2) c1, c2, c3, c4, c5 grm21br60j226me39l murata (3) 22f/6.3v, 0805 ceramic capacitor 5 c6 open open, 0603 ceramic capacitor 1 grm188r71h221ka01d murata (3) vj0603y221kxacw1bc vishay (4) c7 c1608x7r1h221k tdk (1) 220pf, 0603 ceramic capacitor 1 open (vj0603y102kqcw1bc) vishay (4) c8 open (grm188r71h102ka01d) murata (3) 1nf, 0603 ceramic capacitor 1 grm1555c1h390jz01d murata (3) c9 vj0402a390kxqcw1bc vishay (4) 39pf, 0402 ceramic capacitor 1 c3216x5r0j476m tdk (1) 12066d476kat avx (2) c10, c11 grm31cc80g476me19l murata (3) 47f/6v, 1206 ceramic capacitor 2 vj0402a101kxqcw1bc vishay (4) c12 grm15551h101jz01d murata (3) 100pf, 0402 ceramic capacitor 1 d1 dfls220l-7 diodes inc (5) 2a, 20v schottky diode 1 cdrh8d43np-1r2nc sumida (6) fp3-1r0-r coiltronics (7) l1 spm6530t-1r0m120 tdk (1) 1h, 6a inductor 1
micrel, inc. MIC22600 june 2011 25 m9999-062411-d bill of materials (continued) item part number manufacturer description qty r1 crcw06031101fkeye3. vishay (4) 1.1k, 0603 resistor 1 r2 crcw04026980fkeye3. vishay (4) 698? , 0402 resistor 1 r3 crcw06034752fkeye3. vishay (4) 47.5k, 0603 resistor 1 r4 crcw04022002fkeye3. vishay (4) 20k, 0402 resistor 1 rx open open, 0603 resistor 1 q1 open sot-23 1 u1 MIC22600ytse micrel (8) integrated 6a synchronous buck regulator 1 notes: 1. tdk: www.tdk.com . 2. avx: www.avx.com . 3. murata: www.murata.com . 4. vishay: www.vishay.com . 5. diodes inc.: www.diodes.com . 6. sumida: www.sumida.com . 7. coiltronics : www.mouser.com/coiltronics . 8. micrel: www.micrel.com .
micrel, inc. MIC22600 june 2011 26 m9999-062411-d pcb layout recommendations ? ytse package top layer mid layer 1
micrel, inc. MIC22600 june 2011 27 m9999-062411-d pcb layout recommendations ? ytse package (continued) mid layer 2 bottom layer
micrel, inc. MIC22600 june 2011 28 m9999-062411-d package information 24-pin 4mm x 4mm mlf ? (ml)
micrel, inc. MIC22600 june 2011 29 m9999-062411-d package information (continued) 24-pin epad tssop
micrel, inc. MIC22600 june 2011 30 m9999-062411-d recommended landing pattern
micrel, inc. MIC22600 june 2011 31 m9999-062411-d recommended landing pattern (continued)
micrel, inc. MIC22600 june 2011 32 m9999-062411-d 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 it s 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 other wise, to any intellectual property rights is granted by this document. except as provided in micrel?s terms and conditions of sale for such products, mi crel assumes no liability whatsoever, and micrel disclaims any express or implied warranty relating to the sale and/or use of micrel products including l iability or warranties relating to fitness for a particular purpose, merchantability, or infringement of an y patent, copyright or other intellectual p roperty right. micrel products are not designed or authori zed for use as components in life support app liances, devices or systems where malfu nction of a product can reasonably be expected to result in pers onal injury. life support devices or system s are devices or systems that (a) are in tended 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 significan t injury to the user. a purchaser?s use or sale of micrel produc ts for use in life support app liances, 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. ? 2007 micrel, incorporated.

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