description the PAM8202 is a 2 watt per channel, 8-pin, stereo class d audio amplifier, which offers low thd+n (0.10%), allowing it to produce high-quality sound reproduction. the PAM8202 runs off of a 5 volt supply at much higher efficiencies than their class ab cousins, making it ideal for many portable applications. the PAM8202 only requires very few external components (as few as three tiny capacitors), results in significant cost and board space savings. the PAM8202 is available in a sop8 package. typical application circuit 1 features applications 2 watts @ 10% thd per channel output into a 4 ohm load at 5v support speakers or earphone (4 to 32 ). superior low noise without input. supply voltage from 2.5v to 5.5 v. 85% efficiency above. short circuit protection. less output capacitor and inductor to save the space and cost. low thd+n low quiescent current < 10 ma notebook computers. pdas/gps navigator/e-dictionary portable dvd players, game machines. cellular phones,voip phones,screen phones mp3 or pmp players. portable speaker systme,portable amplifier lcd monitor / tv. bluetooth car-kit input input 10k 10k r l vdd 33 h 33 h 33 h 33 h 0.47 f speaker speaker 0.47 f 0.47 f 0.47 f 0.47 f 0.47 f in_l -out_l +out_l +out_r -out_r in_r gnd vdd power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
2 top marking & pin configuration sop8 ordering information assembly location year weekly a y ww package shipping ordering number sop-8 2,500 units/ reel pa m8202s8r absolute maximum ratings: supply voltage: 6v (without input signal) input voltage: -0.3v to vdd +0.3v oo operation temperature range: -40 c to 85 c oo operation junction temperature: -40 c to 125 c oo storage temperature: -65 c to 150 c o maximum junction temperature: 150 c o soldering temperature: 250 c, 10 secretary recommended operating conditions: supply voltage range: 2.5v to 5.5v oo operation temperature range: -40 c to 85 c oo junction temperature range: -40 c to 125 c thermal information: thermal resistance ( ): jc o sop8: 90 c/w ja o dip8: c/w 1 2 3 4 5 6 7 8 pin description left channel audio input. inverted output, left channel. non-inverted output, left channel non-inverted output, right channel. inverted output, right channel. 4 5 6 7 8 in_l -out_l +out_l +out_r - out_r right channel audio input. gndchip ground. supply voltage, need a 1uf ceramic decouple capacitor very close between this pin to gnd pin. pin no. pin name description 1 2 3 in_r gnd vdd electronic specifications parameter min typ max units v condition vdd range 2.5 5 5.5 vdd quiescent current each channel 10 ma sw on resistance vdd = 5v 0.4 sw frequency no input signal 500 khz psrr vdd = 2. 5v to 5.5v -45 db gain 10 v/v vdd = 2.5v to 5.5v, 0 input resistor snr 60 db vdd = 5v, po = 1.5w, 8 load input impedance 100 k ayww power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
3 block diagram input signal left right input signal c1 c2 1 f 1 f c3 1 f vdd vdd 1 bit controller 1 bit controller over current over current left speaker right speaker test circuit for graphs ap system one generator input gnd vdd -out +out PAM8202 demo board load power supply ap system one analyzer ap low pass filter aux-0025 notes: 1. the ap aux-0025 low pass filter is necessary for every class d amplifier measurement done by ap analyzer. 2. a 33uh inductor is used in series with load resistor to emulate the small speaker for efficiency measurement. power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
4 thd+n vs. output power 8 , 1khz, vdd = 5v (%) 100 50 20 10 5 2 1 0.5 0.2 0.1 0.05 0.02 0.01 6 0 0 u 1 m 2 m 5 m 1 0 m 2 0 m 5 0 m 1 0 0 m 2 0 0 m 5 0 0 m 1 2 3 (w) ap thd+n vs. output power 4 , 1khz, vdd = 5v (%) 100 50 20 10 5 2 1 0.5 0.2 0.1 0.05 0.02 0.01 6 0 0 u 1 m 2 m 5 m 1 0 m 2 0 m 5 0 m 1 0 0 m 2 0 0 m 5 0 0 m 1 2 3 (w) ap (%) 100 50 20 10 5 2 1 0.5 0.2 0.1 0.05 0.02 0.01 20 50 100 200 500 1k 2k 5k 10k 20k (hz) 1 ap thd+n vs. frequency 8 , 500mw output, vdd = 5v 100% 80%60% 40% 20% 0% 0 1 2 3 efficiency vs output power e f f i c i e n c y power power dissipation vs. output power 4 , 1khz, vdd = 5v 1.4 1.21.0 0.8 0.6 0.4 0.2 0.0 0 0.5 1 1.5 2 p o w e r d i s s i p a t i o n - w output power -w power dissipation vs. output power 8 , 1khz, vdd = 5v +0 -10-20 -30 -40 -50 -60 -70 -80 -90 -100-110 -120 -130 -140 -150 20 50 100 200 500 1k 2k 5k 10k 20k (dbr) fft noise floor (16k fft) (hz) power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
5 operation information calculating output power of btl amplifier vpk-pk vsupply vsat vsat vsupply output power is related to supply voltage and the saturation voltage (vsat). the maximum peak-to-peak output voltage on one side of btl amplifier output is vp-p = ( vsupply 2 x vsat ) vrms = one side maximum output power of a btl amplifier with 1% thd is 2 pout (1%) = 4 x vrms / rload maximum output power of a btl amplifier with 10% thd is pout (10%) = pout (1%) x 1.25 vp-p 2 2 output power vs. vp-p 5.0 4.03.0 2.0 1.0 0.0 0 1 2 3 4 5 6 btl output power o u t p u t p o w e r @ t h d 1 0 % vdd - vast (v) 8 4 power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
6 input input 10k 10k r l vdd speaker speaker 0.47 f 0.47 f c1 c2 cin cin rin rin 0.47 f c 0.47 f c 0.47 f c 0.47 f c 33 h l 33 h l 33 h l 33 h l setting amplifier voltage gain it is very important to know the maximum output level (0db) of the signal source connected to a power amplifier in order to prevent hard clipping during operation. gain (max) = vsupply/ vin (p-p) insufficient voltage gain will cause low output level and maybe not enough to drive speaker properly. on the other hand, the distortion will be very high if the voltage gain is too high in an audio system. there is a 10k input resistor integrated in side in (input) node, and since the integrated feedback resistor is 100k , so the maximum voltage gain of PAM8202 is limited at 10v/v (100k/10k, one output). with an external input resistor (rin) placed between signal source & input node, the voltage gain will be gain = 100k/ (10k + rin) = vsupply/ vin (p-p) actual voltage gain is two times of this calculation because of btl connection. decouple capacitor PAM8202 is a high performance, high speed class d amplifier, and it requires a 1uf, x7r ceramic decouple capacitor (c1) placed very close between vdd & gnd pins to ensure the total harmonic distortion plus noise (thd+n) performance is as designed. this is also very important for efficiency and lowering noise floor. another 100 f to 1000 f main decouple capacitor (c2) should be placed close to supply pin for low frequency ecoupling. input capacitor input capacitor (cin) blocks the dc voltage between signal source & amplifier to ensure the dc balancing will not be broken between two systems. it also form a high-pass-filter (hpf) with input resistors (rin + 10k), the lower corner frequency (fcl) is determine by equation below. fig. 1 in_l -out_l +out_l +out_r -out_r in_r gnd vdd power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
7 fcl = 1/ [2 x cin x (rin + 10k)] fcl is the lower corner on frequency response curve. cin is very important consider to the lower frequency performance. the cin should not be too large with small speakers as the load, because such small speakers usually can not response with lower frequency, delivering too much low frequency energy into a small speaker which usually got resonant frequency (fs) around 150hz is meaningless and dangerous. this will easily over drive the small speakers. the movement of speaker cone will be too much under such condition and this also creates unnecessary distortion on mid-to high frequency range because the speaker is now operating in non-linear area. speakers can only generate heat but not low frequency sound when it is over driven, the will cause speaker or amplifier failure in some cases. cin should have 10% tolerance or less because the tolerance can cause the input impedance mismatch at fcl and below. output filter the l and c on each output node of PAM8202 form the low-pass-filter (lpf), the higher corner frequency (fch) is determine by equation below. fch = 1/ [2 x sqr (l x c)] fch is the higher corner on frequency response curve. important notice the l-c filters (-12db/oct) gives twice much attenuation and lower impedance (means lower insertion loss) compare to those r-c filters (-6db), but remember, the fch above is also the resonant frequency of this lc network. the quality factor (q) of this resonant network can be very high, depended on the q of l and c. the high resonant q which is usually caused by open-load can generate a very high voltage on speaker terminal, and the impedance of the l-c network can be very low, thus induces large amount of current flows from output stage of PAM8202. this always causes part failure. so do not test open-load on any class d amplifier with output filters. lc filter calculator with output load impedance and cut-off frequency f = , x = 2 fl , x = lc 1 2 lc 1 2 fc power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
8 outline dimension sop8 5.80 - 6.20 1.27 typ. 0.35 - 0.49 4.80 - 5.00 3.80 - 4.00 1.35 - 1.75 45 0.19 - 0.25 0.40 - 0.90 0 - 0.15 0 ~ 8 note: package outline exclusive of mold flash and metal burr. power analog microelectronics, inc. confidential. do not distribute or reproduce without permission from p.a.m. PAM8202 rev. 1.1 prelimiary datasheet PAM8202 tiny package 2 w att class-d stereo audio amplifier
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