View MAX4364-11_9063523.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

general description the max4364/max4365 are bridged audio power amplifiers intended for portable audio devices with internal speakers. the max4364 is capable of deliver- ing 1.4w from a single 5v supply and 500mw from a single 3v supply into an 8 ? load. the max4365 is capable of delivering 1w from a single 5v supply and 450mw from a single 3v supply into an 8 ? load. the max4364/max4365 feature 0.04% thd+n at 1khz, 68db psrr at 217hz, and only 10na of supply current in shutdown mode. the max4364/max4365 bridged outputs eliminate the need for output-coupling capacitors, minimizing exter- nal component count. the max4364/max4365 also include internal dc bias generation, clickless operation, short-circuit and thermal-overload protection. both devices are unity-gain stable, with the gain set by two external resistors. the max4364 is available in a small 8-pin so package. the max4365 is available in tiny 8-pin tdfn (3mm 3mm 0.8mm) and ?ax packages. applications cellular phones pdas two-way radios general-purpose audio features 1.4w into 8? load (max4364) 1w into 8? load (max4365) 0.04% thd+n at 1khz 68db psrr at 217hz 2.7v to 5.5v single-supply operation 5ma supply current low-power, 10na shutdown mode pin compatible with the lm4861/lm4862/lm4864 (max4364) clickless power-up and shutdown thermal-overload and short-circuit protection available in tdfn, max, and so packages max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown ________________________________________________________________ maxim integrated products 1 ordering information 19-2387; rev 4; 5/11 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. part temp range pin-package top mark max4364 esa+ -40? to +85? 8 so max4365 eua+ -40? to +85? 8 ?ax max4365eta+ -40? to +85? 8 tdfn-ep* acd v cc v cc 6 2 3 4 1 8 5 7 out- in- in+ bias c bias c in r in r f 50k ? 50k ? 10k ? 10k ? audio input clickless/popless shutdown control gnd shdn out+ max4364 typical application circuit/functional diagram pin configurations appear at end of data sheet. * ep = exposed pad. + denotes a lead(pb)-free/rohs-compliant package. ?ax is a registered trademark of maxim integrated products, inc.
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown 2 _______________________________________________________________________________________ absolute maximum ratings stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. v cc , out_ to gnd...................................................-0.3v to +6v in+, in-, bias, shdn to gnd....................-0.3v to (v cc + 0.3v) output short circuit (out+ to out-) (note 1)...........continuous continuous power dissipation (t a = +70?) 8-pin ?ax (derate 4.8mw/? above +70?) ..............388mw 8-pin tdfn (derate 24.4mw/? above +70?) ..........1951mw 8-pin so (derate 7.8mw/? above +70?)...................623mw junction temperature ......................................................+150? operating temperature range ...........................-40? to +85? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) .......................................+260? electrical characteristics?v (v cc = 5v, r l = , c bias = 1? to gnd, v shdn = v gnd , t a = +25?, unless otherwise noted.) (note 3) parameter symbol conditions min typ max units supply voltage range v cc inferred from psrr test 2.7 5.5 v max4364 7 13 m ax 4364, t a = t m in to t m ax 17 m ax 4365 5 8 supply current i cc (note 4) m ax 4365, t a = t m in to t m ax 11 ma shutdown supply current i shdn v shdn = v cc 0.01 4 a t a = +25? v cc x 0.7 v ih t a = -40? to +85? (note 5) v cc x 0.7 t a = +25? v cc x 0.3 shdn threshold v il t a = -40? to +85? (note 5) v cc x 0.3 v common-mode bias voltage v bias (note 6) v cc /2 - 5% v cc /2 v cc /2 + 5% v output offset voltage v os in- = out+, in+ = bias (note 7) 1 10 mv v cc = 2.7v to 5.5v dc 55 75 217hz 68 power-supply rejection ratio psrr v ripple = 200mv p-p , r l = 8 ? 1khz 58 db max4364 1200 1400 output power p out r l = 8 ? , thd+n = 1%, f in = 1khz (note 8) max4365 800 1000 mw note 1: continuous power dissipation must also be observed. package thermal characteristics (note 2) note 2: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a four- layer board. for detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial . ?ax junction-to-ambient thermal resistance ( ja ) ......206.3?/w junction-to-case thermal resistance ( jc )................42?/w tdfn junction-to-ambient thermal resistance ( ja ) ...........41?/w junction-to-case thermal resistance ( jc )..................8?/w so junction-to-ambient thermal resistance ( ja ) ......128.4?/w junction-to-case thermal resistance ( jc )................36?/w
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown _______________________________________________________________________________________ 3 electrical characteristics?v (v cc = 3v, r l = , c bias = 1? to gnd, v shdn = v gnd , t a = +25?, unless otherwise noted.) (note 3) parameter symbol conditions min typ max units max4364 6 supply current i cc (note 4) max4365 4.5 ma shutdown supply current i shdn v shdn = v cc 10 na max4364 400 500 output power p out r l = 8 ? , thd+n = 1%, f in = 1khz (note 8) max4365 350 450 mw max4364, p out = 400mw 0.05 total harmonic distortion plus noise thd + n a v = -2v/v, r l = 8 ? , f in = 1khz (notes 5, 9) max4365, p out = 400mw 0.08 % note 3: all specifications are 100% tested at t a = +25?. note 4: quiescent power-supply current is specified and tested with no load on the outputs. quiescent power-supply current depends on the offset voltage when a practical load is connected to the amplifier. note 5: guaranteed by design, not production tested. note 6: common-mode bias voltage is the voltage on bias and is nominally v cc /2. note 7: maximum differential-output offset voltage is tested in a unity-gain configuration. v os = v out+ - v out- . note 8: output power is specified by a combination of a functional output-current test, and characterization analysis. note 9: measurement bandwidth for thd+n is 22hz to 22khz. note 10: extended short-circuit conditions result in a pulsed output. electrical characteristics?v (continued) (v cc = 5v, r l = , c bias = 1? to gnd, v shdn = v gnd , t a = +25?, unless otherwise noted.) (note 3) parameter symbol conditions min typ max units max4364, p out = 1w 0.04 total harmonic distortion plus noise thd+n a v = -2v/v, r l = 8 ? , f in = 1khz (notes 5, 9) max4365, p out = 750mw 0.1 % noise f in = 10khz, bw = 22hz to 22khz 12 ? rms short-circuit current i sc out+ to out- (note 10) 600 ma thermal shutdown threshold 160 o c thermal shutdown hysteresis 15 o c t a = +25? 50 power-up time t pu c bias = 0.22?, t a = -40? to +85? (note 5) 14 35 ms shutdown time t shdn 10 ? t a = +25? 50 enable time from shutdown t enable c bias = 0.22?, t a = -40? to +85? (note 5) 12 35 ms
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown 4 _______________________________________________________________________________________ 1700 1000 525 190 20 0.01 0.1 1 10 100 0.001 0 2500 max4364 toc09 output power (mw) thd+n (%) v cc = 3v a v = 2v/v r l = 8 ? 20khz 20hz 1khz max4364 total harmonic distortion plus noise vs. output power 1650 1000 520 200 40 0.01 0.1 1 10 100 0.001 0 2450 max4364 toc08 output power (mw) thd+n (%) v cc = 5v a v = 4v/v r l = 8 ? 20hz 20khz 1khz max4364 total harmonic distortion plus noise vs. output power 1650 1000 520 200 40 0.01 0.1 1 10 100 0.001 02450 max4364 total harmonic distortion plus noise vs. output power max4364 toc07 output power (mw) thd+n (%) v cc = 5v a v = 2v/v r l = 8 ? 20khz 1khz 20hz max4364 toc06 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 3v a v = 20v/v r l = 8 ? 0.25w 0.4w max4364 total harmonic distortion plus noise vs. frequency max4364 toc05 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 3v a v = 4v/v r l = 8 ? 0.25w 0.4w max4364 total harmonic distortion plus noise vs. frequency max4364 toc04 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 3v a v = 2v/v r l = 8 ? 0.25w 0.4w max4364 total harmonic distortion plus noise vs. frequency max4364 total harmonic distortion plus noise vs. frequency max4364 toc01 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 5v a v = 2v/v r l = 8 ? 0.25w 0.5w 1w max4364 toc02 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 5v a v = 4v/v r l = 8 ? 0.25w 0.5w 1w max4364 total harmonic distortion plus noise vs. frequency max4364 toc03 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 5v a v = 20v/v r l = 8 ? 0.25w 0.5w 1w max4364 total harmonic distortion plus noise vs. frequency typical operating characteristics (v cc = 5v, thd+n measurement bandwidth = 22hz to 22khz, t a = +25?, unless otherwise noted.)
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown _______________________________________________________________________________________ 5 typical operating characteristics (continued) (v cc = 5v, thd+n measurement bandwidth = 22hz to 22khz, t a = +25?, unless otherwise noted.) max4364 shutdown supply current vs. supply voltage max4364 toc18 supply voltage (v) supply current (na) 4.8 4.1 3.4 2 4 6 8 12 0 2.7 5.5 10 max4364 supply current vs. temperature max4364 toc17 temperature ( c) supply current (ma) 35 10 -15 6 7 8 9 10 5 -40 85 60 v cc = 5v max4364 supply current vs. supply voltage max4364 toc16 supply voltage (v) supply current (ma) 4.8 4.1 3.4 6.5 7.0 7.5 8.0 9.0 6.0 2.7 5.5 8.5 max4364 power dissipation vs. output power max4364 toc15 output power (mw) power dissipation (mw) 300 200 100 30 90 210 270 300 0 0500 400 v cc = 3v f in = 1khz r l = 8 ? 150 60 120 240 180 max4364 power dissipation vs. output power max4364 toc14 output power (mw) power dissipation (mw) 900 600 300 70 210 490 630 700 0 0 1500 1200 v cc = 5v f in = 1khz r l = 8 ? 350 140 280 560 420 max4364 output power vs. load resistance max4364 toc13 load resistance ( ? ) output power (mw) 30 20 10 200 400 800 1000 1200 0 050 40 600 v cc = 3v f in = 1khz 10% thd+n 1% thd+n max4364 output power vs. load resistance max4364 toc12 load resistance ( ? ) output power (mw) 30 20 10 600 1200 1800 2400 3000 0 050 40 v cc = 5v f in = 1khz 10% thd+n 1% thd+n max4364 output power vs. supply voltage max4364 toc11 supply voltage (v) output power (mw) 4.8 4.1 3.4 500 1000 1500 2000 2500 0 2.7 5.5 r l = 8 ? f in = 1khz 1% thd+n 10% thd+n 1650 1000 520 200 40 0.01 0.1 1 10 100 0.001 02440 max4364 toc10 output power (mw) thd+n (%) v cc = 3v a v = 4v/v r l = 8 ? 20khz 20hz 1khz max4364 total harmonic distortion plus noise vs. output power
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown 6 _______________________________________________________________________________________ typical operating characteristics (continued) (v cc = 5v, thd+n measurement bandwidth = 22hz to 22khz, t a = +25?, unless otherwise noted.) max4364 toc27 output power (mw) thd+n (%) 2000 1600 1300 1000 750 500 0.01 0.1 1 10 100 0.001 2400 v cc = 5v a v = 4v/v r l = 8 ? 20khz 20hz 1khz max4365 total harmonic distortion plus noise vs. output power max4364 toc24 max4365 total harmonic distortion plus noise vs. frequency frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 3v a v = 4v/v r l = 8 ? 0.25w 0.4w max4365 total harmonic distortion plus noise vs. frequency max4364 toc23 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 3v a v = 2v/v r l = 8 ? 0.25w 0.4w max4364 toc22 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 5v a v = 20v/v r l = 8 ? 0.25w 0.5w 0.75w max4365 total harmonic distortion plus noise vs. frequency max4364 toc26 output power (mw) thd+n (%) 2000 1600 1300 1000 700 500 300 200 0.01 0.1 1 10 100 0.001 0 2400 v cc = 5v a v = 2v/v r l = 8 ? 20khz 20hz 1khz max4365 total harmonic distortion plus noise vs. output power max4364 toc25 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 3v a v = 20v/v r l = 8 ? 0.25w 0.4w max4365 total harmonic distortion plus noise vs. frequency max4364 toc21 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 5v a v = 4v/v r l = 8 ? 0.25w 0.5w 0.75w max4365 total harmonic distortion plus noise vs. frequency max4365 total harmonic distortion plus noise vs. frequency max4364 toc20 frequency (hz) thd+n (%) 100 1k 0.1 1 10 0.01 010k v cc = 5v a v = 2v/v r l = 8 ? 0.25w 0.5w 0.75w max4364 shutdown supply current vs. temperature max4364 toc19 temperature ( c) supply current (na) 35 10 -15 20 40 60 80 100 0 -40 85 60 v cc = 5v
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown _______________________________________________________________________________________ 7 typical operating characteristics (continued) (v cc = 5v, thd+n measurement bandwidth = 22hz to 22khz, t a = +25?, unless otherwise noted.) max4365 supply current vs. supply voltage max4364 toc35 supply voltage (v) supply current (ma) 4.1 3.4 4 5 6 7 3 2.7 5.5 4.8 max4365 power dissipation vs. output power max4364 toc34 output power (mw) power dissipation (mw) 300 200 100 50 100 150 200 250 0 0500 400 v cc = 3v r l = 8 ? f in = 1khz max4365 power dissipation vs. output power max4364 toc33 output power (mw) power dissipation (mw) 900 600 300 200 400 600 800 0 0 1500 1200 v cc = 5v r l = 8 ? f in = 1khz max4365 output power vs. load resistance max4364 toc32 load resistance ( ? ) output power (mw) 30 20 10 400 600 800 1000 1200 0 050 10% thd+n 1% thd+n 40 v cc = 3v f in = 1khz 200 max4365 output power vs. load resistance max4364 toc31 load resistance ( ? ) output power (mw) 30 20 10 200 400 600 800 1000 1200 0 050 40 v cc = 5v f in = 1khz max4365 supply current vs. temperature max4364 toc36 temperature ( c) supply current (ma) 35 10 -15 4 5 6 7 3 -40 85 60 v cc = 5v max4365 output power vs. supply voltage max4364 toc30 supply voltage (v) output power (mw) 4.8 4.1 3.4 500 1000 1500 2000 2500 0 2.7 5.5 r l = 8 ? f in = 1khz 1% thd+n 10% thd+n max4364 toc29 output power (mw) thd+n (%) 725 600 500 400 325 250 200 125 0.01 0.1 1 10 100 0.001 0 850 1000 v cc = 3v a v = 4v/v r l = 8 ? 20khz 20hz 1khz max4365 total harmonic distortion plus noise vs. output power max4364 toc28 output power (mw) thd+n (%) 725 600 500 400 325 250 200 125 0.01 0.1 1 10 100 0.001 0 800 1000 v cc = 3v a v = 2v/v r l = 8 ? 20khz 20hz 1khz max4365 total harmonic distortion plus noise vs. output power
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown 8 _______________________________________________________________________________________ typical operating characteristics (continued) (v cc = 5v, thd+n measurement bandwidth = 22hz to 22khz, t a = +25?, unless otherwise noted.) gain and phase vs. frequency max4364 toc39 frequency (hz) gain/phase (db/degrees) 1m 100k 10k 1k 100 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 -180 10 10m a v = 1000v/v power-supply rejection ratio vs. frequency max4364 toc40 frequency (hz) psrr (db) 10k 1k 100 -70 -60 -50 -40 -30 -20 -80 10 100k r l = 8 ? v ripple = 200mv p-p pin description pin max4364 max4365 so ?ax/tdfn name function 1 7 shdn active-high shutdown. connect shdn to gnd for normal operation. 2 1 bias dc bias bypass. see bias capacitor section for capacitor selection. connect c bias capacitor from bias to gnd. 3 2 in+ noninverting input 4 4 in- inverting input 5 5 out+ bridged amplifier positive output 66v cc power supply 7 3 gnd ground 8 8 out- bridged amplifier negative output ep exposed pad (tdfn only). internally connected to gnd. connect to a large ground plane to maximize thermal performance. not intended as an electrical connection point. max4365 shutdown supply current vs. temperature max4364 toc38 temperature ( c) supply current (na) 35 10 -15 20 30 10 40 50 60 70 80 0 -40 85 60 v cc = 5v max4365 shutdown supply current vs. supply voltage max4364 toc37 supply voltage (v) supply current (na) 4.8 4.1 3.4 2 4 6 8 12 0 2.7 5.5 10
detailed description the max4364/max4365 bridged audio power ampli- fiers can deliver 1.4w into 8 ? (max4364) or 1w into 8 ? (max4365) while operating from a single 5v supply. these devices consist of two high-output-current op amps configured as a bridge-tied load (btl) amplifier (see typical application circuit/functional diagram ). the gain of the device is set by the closed-loop gain of the input op amp. the output of the first amplifier serves as the input to the second amplifier, which is configured as an inverting unity-gain follower in both devices. this results in two outputs, identical in magni- tude, but 180 out of phase. bias the max4364/max4365 feature an internally generated common-mode bias voltage of v cc /2 referenced to gnd. bias provides both click-and-pop suppression and the dc bias level for the audio signal. bias is inter- nally connected to the noninverting input of one amplifi- er, and should be connected to the noninverting input of the other amplifier for proper signal biasing (see typical application circuit/functional diagram ). choose the value of the bypass capacitor as described in the bias capacitor section. shutdown the max4364/max4365 feature a 10na, low-power shutdown mode that reduces quiescent current con- sumption. pulling shdn high disables the device? bias circuitry, the amplifier outputs go high impedance, and bias is driven to gnd. connect shdn to gnd for nor- mal operation. current limit the max4364/max4365 feature a current limit that pro- tects the device during output short circuit and over- load conditions. when both amplifier outputs are shorted to either v cc or gnd, the short-circuit protec- tion is enabled and the amplifier enters a pulsing mode, reducing the average output current to a safe level. the amplifier remains in this mode until the overload or short-circuit condition is removed. applications information bridge-tied load the max4364/max4365 are designed to drive a load differentially in a btl configuration. the btl configura- tion (figure 1) offers advantages over the single-ended configuration, where one side of the load is connected to ground. driving the load differentially doubles the output voltage compared to a single-ended amplifier under similar conditions. thus, the differential gain of the device is twice the closed-loop gain of the input amplifier. the effective gain is given by: substituting 2 v out(p-p) into the following equations yields four times the output power due to doubling of the output voltage. since the differential outputs are biased at midsupply, there is no net dc voltage across the load. this elimi- nates the need for dc-blocking capacitors required for single-ended amplifiers. these capacitors can be large, expensive, consume board space, and degrade low-frequency performance. power dissipation under normal operating conditions, the max4364/ max4365 can dissipate a significant amount of power. the maximum power dissipation for each package is given in the absolute maximum ratings section under continuous power dissipation or can be calculated by the following equation: where t j(max) is +150?, t a is the ambient temperature and ja is the reciprocal of the derating factor in ?/w as specified in the package thermal characteristics section. for example, ja of the ?ax package is 206.3?/w. p tt disspkg max j max a ja () () = ? v v p v r rms out p p out rms l = = ? () 22 2 a r r vd f in = 2 max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown _______________________________________________________________________________________ 9 +1 v out(p-p) 2 x v out(p-p) v out(p-p) -1 figure 1. bridge-tied load configuration
max4364/max4365 the increase in power delivered by the btl configura- tion directly results in an increase in internal power dis- sipation over the single-ended configuration. the maximum power dissipation for a given v cc and load is given by the following equation: if the power dissipation for a given application exceeds the maximum allowed for a given package, reduce v cc , increase load impedance, decrease the ambient temperature or add heat sinking to the device. large output, supply, and ground pc board traces improve the maximum power dissipation in the package. thermal-overload protection limits total power dissipa- tion in the max4364/max4365. when the junction tem- perature exceeds +160?, the thermal protection circuitry disables the amplifier output stage. the ampli- fiers are enabled once the junction temperature cools by 15?. this results in a pulsing output under continu- ous thermal overload conditions as the device heats and cools. the max4365 tdfn package features an exposed thermal pad on its underside. this pad lowers the ther- mal resistance of the package by providing a direct heat conduction path from the die to the pc board. connect the exposed thermal pad to circuit ground by using a large pad, ground plane, or multiple vias to the ground plane. efficiency the efficiency of the max4364/max4365 is calculated by taking the ratio of the power delivered to the load to the power consumed from the power supply. output power is calculated by the following equations: where v peak is half the peak-to-peak output voltage. in btl amplifiers, the supply current waveform is a full- wave rectified sinusoid with the magnitude proportional to the peak output voltage and load. calculate the sup- ply current and power drawn from the power supply by the following: the efficiency of the max4364/max4365 is: the device efficiency values in table 1 are calculated based on the previous equation and do include the effects of quiescent current. note that efficiency is low at low output-power levels, but remains relatively con- stant at normal operating, output-power levels. component selection gain-setting resistors external feedback components set the gain of both devices. resistors r f and r in (see typical application circuit/functional diagram ) set the gain of the amplifier as follows: optimum output offset is achieved when r f = 20k ? . vary the gain by changing the value of r in . when using the max4364/max4365 in a high-gain configuration (greater than 8v/v), a feedback capacitor may be required to maintain stability (see figure 2). c f and r f limit the bandwidth of the device, preventing high-fre- quency oscillations. ensure that the pole created by c f and r f is not within the frequency band of interest. input filter the input capacitor (c in ), in conjunction with r in forms a highpass filter that removes the dc bias from an incoming signal. the ac-coupling capacitor allows the amplifier to bias the signal to an optimum dc level. assuming zero source impedance, the -3db point of the highpass filter is given by: choose r in according to the gain-setting resistors section. choose c in such that f -3db is well below the lowest frequency of interest. setting f -3db too high affects the low-frequency response of the amplifier. use capacitors whose dielectrics have low-voltage coeffi- ?= ? 3 1 2 db in in rc a r r vd f in = 2 == p p pr v out in out l cc 2 2 pv v r in cc peak l = ? ? ? ? ? ? 2 i v r cc peak l = 2 p v r out peak l = 2 2 p v r diss max cc l () = 2 2 2 1.4w and 1w, ultra-small, audio power amplifiers with shutdown 10 ______________________________________________________________________________________
cients, such as tantalum or aluminum electrolytic. capacitors with high-voltage coefficients, such as ceramics, may result in an increase distortion at low frequencies. other considerations when designing the input filter include the constraints of the overall system, the actual frequency band of interest and click-and-pop suppres- sion. although high-fidelity audio calls for a flat gain response between 20hz and 20khz, portable voice- reproduction devices such as cellular phones and two- way radios need only concentrate on the frequency range of the spoken human voice (typically 300hz to 3.5khz). in addition, speakers used in portable devices typically have a poor response below 150hz. taking these two factors into consideration, the input filter may not need to be designed for a 20hz to 20khz response, saving both board space and cost due to the use of smaller capacitors. bias capacitor the bias bypass capacitor, c bias , improves psrr and thd+n by reducing power-supply noise at the common- mode bias node, and serves as the primary click-and- pop suppression mechanism. c bias is fed from an internal 25k ? source, and controls the rate at which the common-mode bias voltage rises at startup and falls during shutdown. for optimum click-and-pop suppres- sion, ensure that the input capacitor (c in ) is fully charged (ten time constants) before c bias . the value of c bias for best click-and-pop suppression is given by: in addition, a larger c bias value yields higher psrr. c cr k bias in in ? ? ? ? ? ? 10 25 ? max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown ______________________________________________________________________________________ 11 output power (w) internal power dissipation (w) efficiency (%) 0.25 0.55 31.4 0.50 0.63 44.4 0.75 0.63 54.4 1.00 0.59 62.8 1.25 0.53 70.2 1.40 0.48 74.3 v cc v cc c in r in r f c f c bias 6 out- in+ bias audio input 3 2 clickless/ popless shutdown control gnd shdn 8 out+ 5 7 1 max4364 max4365 50k ? 50k ? 10k ? 10k ? in- 4 figure 2. high-gain configuration table 1. efficiency in a 5v, 8? btl system
max4364/max4365 clickless/popless operation proper selection of ac-coupling capacitors (c in ) and c bias achieves clickless/popless shutdown and startup. the value of c bias determines the rate at which the midrail bias voltage rises on startup and falls when enter- ing shutdown. the size of the input capacitor also affects clickless/popless operation. on startup, c in is charged to its quiescent dc voltage through the feedback resistor (r f ) from the output. this current creates a voltage tran- sient at the amplifier? output, which can result in an audible pop. minimizing the size of c in reduces this effect, optimizing click-and-pop suppression. supply bypassing proper supply bypassing ensures low-noise, low-distor- tion performance. place a 0.1? ceramic capacitor in parallel with a 10? ceramic capacitor from v cc to gnd. locate the bypass capacitors as close to the device as possible. adding volume control the addition of a digital potentiometer provides simple volume control. figure 3 shows the max4364/max4365 with the max5407 log taper digital potentiometer used as an input attenuator. connect the high terminal of the max5407 to the audio input, the low terminal to ground and the wiper to c in . setting the wiper to the top posi- tion passes the audio signal unattenuated. setting the wiper to the lowest position fully attenuates the input. layout considerations good layout improves performance by decreasing the amount of stray capacitance and noise at the amplifier? inputs and outputs. decrease stray capacitance by min- imizing pc board trace lengths, using surface-mount components and placing external components as close to the device as possible. also refer to the power dissipation section for heatsinking considerations. 1.4w and 1w, ultra-small, audio power amplifiers with shutdown 12 ______________________________________________________________________________________ out+ audio input out- in- 1h w3 c in r f r in 4l max4364 max4365 max5407 figure 3. max4364/max4365 and max5160 volume control circuit chip information process: bicmos max tdfn 2 7 shdn in+ 8 out- 1 1234 8765 bias + v cc gnd 3 6 out+ shdn out- v cc out+ in- in+ bias gnd in- ep* *connect ep to gnd. + 45 max4365 max4364 max4365 v cc out+ in- 1 2 8 7 out- + gnd bias in+ shdn so top view 3 4 6 5 max4364 pin configurations
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown ______________________________________________________________________________________ 13 package information for the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages . note that a ?? ?? or ??in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing per - tains to the package regardless of rohs status. package type package code outline no. land pattern no. 8 so s8+5 21-0041 90-0096 8 ?ax u8+1 21-0036 90-0092 8 tdfn t833+2 21-0137 90-0059
max4364/max4365 1.4w and 1w, ultra-small, audio power amplifiers with shutdown maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 14 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 4 5/11 added ep information to pin description ; updated ordering information and pin configurations for lead-free parts; updated specifications in absolute maximum ratings , package thermal characteristics and electrical characteristics sections 1, 2, 3, 8, 9, 12, 13

▲Up To Search▲

Price & Availability of MAX4364-11

	To Download MAX4364-11 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .