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1/28 n operating from v cc = 2.5v to 5.5v n 1w rail to rail output power @ vcc=5v, thd=1%, f=1khz, with 8 w load n ultra low consumption in standby mode (10na) n 75db psrr @ 217hz from 5v to 2.6v n ultra low pop & click n ultra low distortion (0.1%) n unity gain stable n available in so8, miniso8 & dfn8 3x3mm description the ts4871 is an audio power amplifier capable of delivering 1w of continuous rms ouput power into 8 w load @ 5v. this audio amplifier is exhibiting 0.1% distortion level (thd) from a 5v supply for a pout = 250mw rms. an external standby mode control reduces the supply current to less than 10na. an internal thermal shutdown protection is also provided. the ts4871 has been designed for high quality audio applications such as mobile phones and to minimize the number of external components. the unity-gain stable amplifier can be configured by external gain setting resistors. applications n mobile phones (cellular / cordless) n laptop / notebook computers n pdas n portable audio devices order code miniso & dfn only available in tape & reel with t suffix(ist & iqt) d = small outline package (so) - also available in tape & reel (dt) pin connections (top view) part number temperature range: i package marking ds q ts4871 -40, +85c 4871i 4871 standby bypass v+ in v in- v2 out gnd v cc v out1 1 2 3 4 8 7 6 5 rin cin rstb cb rfeed 4 3 2 1 5 8 vin- vin+ - + - + bypass standby bias 6 vout1 vout2 av=-1 ts4871 rl 8 ohms vcc gnd audio input vcc vcc cfeed cs 7 typical application schematic TS4871IST - miniso8 ts4871id-ts4871idt - so8 standby bypass v+ in v in- v2 out gnd v cc v out1 1 2 3 4 8 7 6 5 1 2 3 4 5 8 7 6 standby bypass v out 2 v in- v in+ vcc v out 1 gnd 1 2 3 4 5 8 7 6 standby bypass v out 2 v in- v in+ vcc v out 1 gnd ts4871iqt - dfn8 ts4871 output rail to rail 1w audio power amplifier with standby mode june 2003
ts4871 2/28 absolute maximum ratings operating conditions symbol parameter value unit v cc supply voltage 1) 6v v i input voltage 2) g nd to v cc v t oper operating free air temperature range -40 to + 85 c t stg storage temperature -65 to +150 c t j maximum junction temperature 150 c r thja thermal resistance junction to ambient 3) so8 miniso8 qnf8 175 215 70 c/w pd power dissipation internally limited 4) esd human body model 2 kv esd machine model 200 v latch-up latch-up immunity class a lead temperature (soldering, 10sec) 260 c 1. all voltages values are measured with respect to the ground pin. 2. the magnitude of input signal must never exceed v cc + 0.3v / g nd - 0.3v 3. device is protected in case of over temperature by a thermal shutdown active @ 150c. 4. exceeding the power derating curves during a long period, involves abnormal operating condition. symbol parameter value unit v cc supply voltage 2.5 to 5.5 v v icm common mode input voltage range g nd to v cc - 1.2v v v stb standby voltage input : device on device off g nd v stb 0.5v v cc - 0.5v v stb v cc v r l load resistor 4 - 32 w r thja thermal resistance junction to ambient 1) so8 miniso8 dfn8 2) 150 190 41 c/w 1. this thermal resistance can be reduced with a suitable pcb layout (see power derating curves fig. 20) 2. when mounted on a 4 layers pcb
ts4871 3/28 electrical characteristics v cc = +5v , gnd = 0v , t amb = 25c (unless otherwise specified) v cc = +3.3v , gnd = 0v , t amb = 25c (unless otherwise specified) 3) symbol parameter min. typ. max. unit i cc supply current no input signal, no load 68ma i standby standby current 1) no input signal, vstdby = vcc, rl = 8 w 1. standby mode is actived when vstdby is tied to vcc 10 1000 na voo output offset voltage no input signal, rl = 8 w 520mv po output power thd = 1% max, f = 1khz, rl = 8 w 1w thd + n total harmonic distortion + noise po = 250mw rms, gv = 2, 20hz < f < 20khz, rl = 8 w 0.15 % psrr power supply rejection ratio 2) f = 217hz, rl = 8 w, rfeed = 22k w, vripple = 200mv rms 2. dynamic measurements - 20*log(rms(vout)/rms(vripple)). vripple is the surimposed sinus signal to vcc @ f = 217hz 75 db f m phase margin at unity gain r l = 8 w , c l = 500pf 70 degrees gm gain margin r l = 8 w , c l = 500pf 20 db gbp gain bandwidth product r l = 8 w 2mhz symbol parameter min. typ. max. unit i cc supply current no input signal, no load 5.5 8 ma i standby standby current 1) no input signal, vstdby = vcc, rl = 8 w 1. standby mode is actived when vstdby is tied to vcc 10 1000 na voo output offset voltage no input signal, rl = 8 w 520mv po output power thd = 1% max, f = 1khz, rl = 8 w 450 mw thd + n total harmonic distortion + noise po = 250mw rms, gv = 2, 20hz < f < 20khz, rl = 8 w 0.15 % psrr power supply rejection ratio 2) f = 217hz, rl = 8 w, rfeed = 22k w, vripple = 200mv rms 2. dynamic measurements - 20*log(rms(vout)/rms(vripple)). vripple is the surimposed sinus signal to vcc @ f = 217hz 3. all electrical values are made by correlation between 2.6v and 5v measurements 75 db f m phase margin at unity gain r l = 8 w , c l = 500pf 70 degrees gm gain margin r l = 8 w , c l = 500pf 20 db gbp gain bandwidth product r l = 8 w 2mhz
ts4871 4/28 electrical characteristics v cc = 2.6v , gnd = 0v , t amb = 25c (unless otherwise specified) remarks 1. all measurements, except psrr measurements, are made with a supply bypass capacitor cs = 100f. 2. external resistors are not needed for having better stability when supply @ vcc down to 3v. by the way, the quiescent current remains the same. 3. the standby response time is about 1s. symbol parameter min. typ. max. unit i cc supply current no input signal, no load 5.5 8 ma i standby standby current 1) no input signal, vstdby = vcc, rl = 8 w 1. standby mode is actived when vstdby is tied to vcc 10 1000 na voo output offset voltage no input signal, rl = 8 w 520mv po output power thd = 1% max, f = 1khz, rl = 8 w 260 mw thd + n total harmonic distortion + noise po = 200mw rms, gv = 2, 20hz < f < 20khz, rl = 8 w 0.15 % psrr power supply rejection ratio 2) f = 217hz, rl = 8 w, rfeed = 22k w, vripple = 200mv rms 2. dynamic measurements - 20*log(rms(vout)/rms(vripple)). vripple is the surimposed sinus signal to vcc @ f = 217hz 75 db f m phase margin at unity gain r l = 8 w , c l = 500pf 70 degrees gm gain margin r l = 8 w , c l = 500pf 20 db gbp gain bandwidth product r l = 8 w 2mhz components functional description rin inverting input resistor which sets the closed loop gain in conjunction with rfeed. this resistor also forms a high pass filter with cin (fc = 1 / (2 x pi x rin x cin)) cin input coupling capacitor which blocks the dc voltage at the amplifier input terminal rfeed feed back resistor which sets the closed loop gain in conjunction with rin cs supply bypass capacitor which provides power supply filtering cb bypass pin capacitor which provides half supply filtering cfeed low pass filter capacitor allowing to cut the high frequency (low pass filter cut-off frequency 1 / (2 x pi x rfeed x cfeed)) rstb pull-up resistor which fixes the right supply level on the standby pin gv closed loop gain in btl configuration = 2 x (rfeed / rin)
ts4871 5/28 fig. 1 : open loop frequency response fig. 3 : open loop frequency response fig. 5 : open loop frequency response fig. 2 : open loop frequency response fig. 4 : open loop frequency response fig. 6 : open loop frequency response 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 vcc = 5v rl = 8 w tamb = 25 c gain (db) frequency (khz) gain phase phase (deg) 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 80 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 gain (db) frequency (khz) vcc = 3.3v rl = 8 w tamb = 25 c gain phase phase (deg) 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 80 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 gain (db) frequency (khz) vcc = 2.6v rl = 8 w tamb = 25 c gain phase phase (deg) 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 gain (db) frequency (khz) vcc = 5v zl = 8 w + 560pf tamb = 25 c gain phase phase (deg) 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 80 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 gain (db) frequency (khz) vcc = 3.3v zl = 8 w + 560pf tamb = 25 c gain phase phase (deg) 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 80 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 gain (db) frequency (khz) vcc = 2.6v zl = 8 w + 560pf tamb = 25 c gain phase phase (deg)
ts4871 6/28 fig. 7 : open loop frequency response fig. 9 : open loop frequency response fig. 8 : open loop frequency response 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 80 100 -220 -200 -180 -160 -140 -120 -100 -80 gain (db) frequency (khz) vcc = 5v cl = 560pf tamb = 25 c gain phase phase (deg) 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 80 100 -240 -220 -200 -180 -160 -140 -120 -100 -80 gain (db) frequency (khz) vcc = 2.6v cl = 560pf tamb = 25 c gain phase phase (deg) 0.3 1 10 100 1000 10000 -40 -20 0 20 40 60 80 100 -240 -220 -200 -180 -160 -140 -120 -100 -80 gain (db) frequency (khz) vcc = 3.3v cl = 560pf tamb = 25 c gain phase phase (deg)
ts4871 7/28 fig. 10 : power supply rejection ratio (psrr) vs power supply fig. 12 : power supply rejection ratio (psrr) vs bypass capacitor fig. 14 : power supply rejection ratio (psrr) vs feedback resistor fig. 11 : power supply rejection ratio (psrr) vs feedback capacitor fig. 13 : power supply rejection ratio (psrr) vs input capacitor 10 100 1000 10000 100000 -80 -70 -60 -50 -40 -30 vcc = 5v, 3.3v & 2.6v cb = 1 m f & 0.1 m f vripple = 200mvrms rfeed = 22 w input = floating rl = 8 w tamb = 25 c psrr (db) frequency (hz) 10 100 1000 10000 100000 -80 -70 -60 -50 -40 -30 -20 -10 cb=100 m f cb=10 m f cb=47 m f cb=1 m f vcc = 5, 3.3 & 2.6v rfeed = 22k rin = 22k, cin = 1 m f rg = 100 w , rl = 8 w tamb = 25 c psrr (db) frequency (hz) 10 100 1000 10000 100000 -80 -70 -60 -50 -40 -30 -20 -10 rfeed=10k w rfeed=22k w rfeed=47k w rfeed=110k w vcc = 5, 3.3 & 2.6v cb = 1 m f & 0.1 m f vripple = 200mvrms input = floating rl = 8 w tamb = 25 c psrr (db) frequency (hz) 10 100 1000 10000 100000 -80 -70 -60 -50 -40 -30 -20 -10 cfeed=680pf cfeed=330pf cfeed=150pf cfeed=0 vcc = 5, 3.3 & 2.6v cb = 1 m f & 0.1 m f rfeed = 22k w vripple = 200mvrms input = floating rl = 8 w tamb = 25 c psrr (db) frequency (hz) 10 100 1000 10000 100000 -60 -50 -40 -30 -20 -10 vcc = 5, 3.3 & 2.6v rfeed = 22k w , rin = 22k cb = 1 m f rg = 100 w , rl = 8 w tamb = 25 c cin=22nf cin=100nf cin=220nf cin=330nf cin=1 m f psrr (db) frequency (hz)
ts4871 8/28 fig. 15 : pout @ thd + n = 1% vs supply voltage vs rl fig. 17 : power dissipation vs pout fig. 19 : power dissipation vs pout fig. 16 : pout @ thd + n = 10% vs supply voltage vs rl fig. 18 : power dissipation vs pout fig. 20 : power derating curves 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 32 w 16 w 4 w 6 w gv = 2 & 10 cb = 1 m f f = 1khz bw < 125khz tamb = 25 c 8 w output power @ 1% thd + n (w) vcc (v) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 rl=16 w rl=8 w vcc=5v f=1khz thd+n<1% rl=4 w power dissipation (w) output power (w) 0.0 0.1 0.2 0.3 0.4 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 rl=4 w rl=8 w vcc=2.6v f=1khz thd+n<1% rl=16 w power dissipation (w) output power (w) 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 4 w 6 w 8 w 16 w 32 w gv = 2 & 10 cb = 1 m f f = 1khz bw < 125khz tamb = 25 c output power @ 10% thd + n (w) vcc (v) 0.0 0.2 0.4 0.6 0.8 0.0 0.1 0.2 0.3 0.4 0.5 0.6 rl=4 w rl=8 w vcc=3.3v f=1khz thd+n<1% rl=16 w power dissipation (w) output power (w) 0 25 50 75 100 125 150 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 so8 miniso8 qfn8 power dissipation (w) ambiant temperature (c)
ts4871 9/28 fig. 21 : thd + n vs output power fig. 23 : thd + n vs output power fig. 25 : thd + n vs output power fig. 22 : thd + n vs output power fig. 24 : thd + n vs output power fig. 26 : thd + n vs output power 1e-3 0.01 0.1 1 0.1 1 10 rl = 4 w vcc = 5v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 4 w , vcc = 3.3v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.1 1 10 rl = 4 w , vcc = 2.6v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 4 w , vcc = 5v gv = 10 cb = cin = 1 m f bw < 125khz, tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 4 w , vcc = 3.3v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.1 1 10 rl = 4 w , vcc = 2.6v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w)
ts4871 10/28 fig. 27 : thd + n vs output power fig. 29 : thd + n vs output power fig. 31 : thd + n vs output power fig. 28 : thd + n vs output power fig. 30 : thd + n vs output power fig. 32 : thd + n vs output power 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w vcc = 5v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w , vcc = 3.3v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.1 1 10 rl = 8 w , vcc = 2.6v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w vcc = 5v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w , vcc = 3.3v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.1 1 10 rl = 8 w , vcc = 2.6v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w)
ts4871 11/28 fig. 33 : thd + n vs output power fig. 35 : thd + n vs output power fig. 37 : thd + n vs output power fig. 34 : thd + n vs output power fig. 36 : thd + n vs output power fig. 38 : thd + n vs output power 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w vcc = 5v gv = 2 cb = 0.1 m f, cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w , vcc = 3.3v gv = 2 cb = 0.1 m f, cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.1 1 10 rl = 8 w , vcc = 2.6v gv = 2 cb = 0.1 m f, cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w , vcc = 5v, gv = 10 cb = 0.1 m f, cin = 1 m f bw < 125khz, tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.1 1 10 rl = 8 w , vcc = 3.3v, gv = 10 cb = 0.1 m f, cin = 1 m f bw < 125khz, tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.1 1 10 rl = 8 w , vcc = 2.6v, gv = 10 cb = 0.1 m f, cin = 1 m f bw < 125khz, tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w)
ts4871 12/28 fig. 39 : thd + n vs output power fig. 41 : thd + n vs output power fig. 43 : thd + n vs output power fig. 40 : thd + n vs output power fig. 42 : thd + n vs output power fig. 44 : thd + n vs output power 1e-3 0.01 0.1 1 0.01 0.1 1 10 rl = 16 w , vcc = 5v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.01 0.1 1 10 rl = 16 w , vcc = 3.3v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.01 0.1 1 10 rl = 16 w vcc = 2.6v gv = 2 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz, 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 1 0.01 0.1 1 10 rl = 16 w , vcc = 5v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.01 0.1 1 10 rl = 16 w vcc = 3.3v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w) 1e-3 0.01 0.1 0.01 0.1 1 10 rl = 16 w vcc = 2.6v gv = 10 cb = cin = 1 m f bw < 125khz tamb = 25 c 20khz 20hz 1khz thd + n (%) output power (w)
ts4871 13/28 fig. 45 : thd + n vs frequency fig. 47 : thd + n vs frequency fig. 49 : thd + n vs frequency fig. 46 : thd + n vs frequency fig. 48 : thd + n vs frequency fig. 50 : thd + n vs frequency 20 100 1000 10000 0.1 1 pout = 600mw pout = 1.2w rl = 4 w , vcc = 5v gv = 2 cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 pout = 270mw pout = 540mw rl = 4 w , vcc = 3.3v gv = 2 cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 pout = 120mw pout = 240mw rl = 4 w , vcc = 2.6v gv = 2 cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.01 0.1 1 pout = 600mw pout = 1.2w rl = 4 w , vcc = 5v gv = 10 cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 pout = 270mw pout = 540mw rl = 4 w , vcc = 3.3v gv = 10 cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 pout = 240 & 120mw rl = 4 w , vcc = 2.6v gv = 10 cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz)
ts4871 14/28 fig. 51 : thd + n vs frequency fig. 53 : thd + n vs frequency fig. 55 : thd + n vs frequency fig. 52 : thd + n vs frequency fig. 54 : thd + n vs frequency fig. 56 : thd + n vs frequency 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w vcc = 5v gv = 2 pout = 900mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 5v gv = 10 pout = 900mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 3.3v gv = 2 pout = 400mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w vcc = 5v gv = 2 pout = 450mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 5v gv = 10 pout = 450mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 3.3v gv = 2 pout = 200mw bw < 125khz tamb = 25c thd + n (%) frequency (hz)
ts4871 15/28 fig. 57 : thd + n vs frequency fig. 59 : thd + n vs frequency fig. 61 : thd + n vs frequency fig. 58 : thd + n vs frequency fig. 60 : thd + n vs frequency fig. 62 : thd + n vs frequency 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 3.3v gv = 10 pout = 400mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 2.6v gv = 2 pout = 220mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 2.6v gv = 10 pout = 220mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 3.3v gv = 10 pout = 200mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 2.6v gv = 2 pout = 110mw bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 cb = 0.1f cb = 1f rl = 8 w , vcc = 2.6v gv = 10 pout = 110mw bw < 125khz tamb = 25c thd + n (%) frequency (hz)
ts4871 16/28 fig. 63 : thd + n vs frequency fig. 65 : thd + n vs frequency fig. 67 : thd + n vs frequency fig. 64 : thd + n vs frequency fig. 66 : thd + n vs frequency fig. 68 : thd + n vs frequency 20 100 1000 10000 0.01 0.1 1 pout = 310mw pout = 620mw rl = 16 w , vcc = 5v gv = 2, cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.01 0.1 1 pout = 135mw pout = 270mw rl = 16 w , vcc = 3.3v gv = 2, cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.01 0.1 1 pout = 80mw pout = 160mw rl = 16 w , vcc = 2.6v gv = 2, cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.01 0.1 1 pout = 310mw pout = 620mw rl = 16 w , vcc = 5v gv = 10, cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.1 1 pout = 135mw pout = 270mw rl = 16 w , vcc = 3.3v gv = 10 cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz) 20 100 1000 10000 0.01 0.1 1 pout = 80mw pout = 160mw rl = 16 w , vcc = 2.6v gv = 10, cb = 1f bw < 125khz tamb = 25c thd + n (%) frequency (hz)
ts4871 17/28 fig. 69 : signal to noise ratio vs power supply with unweighted filter (20hz to 20khz) fig. 71 : signal to noise ratio vs power supply with weighted filter type a fig. 73 : signal to noise ratio vs power supply with unweighted filter (20hz to 20khz) fig. 70 : signal to noise ratio vs power supply with weighted filter type a fig. 72 : current consumption vs power supply voltage fig. 74 : current consumption vs standby voltage @ vcc = 5v 2.5 3.0 3.5 4.0 4.5 5.0 50 60 70 80 90 100 rl=8 w rl=4 w rl=16 w gv = 2 cb = cin = 1f thd+n < 0.4% tamb = 25c snr (db) vcc (v) 2.5 3.0 3.5 4.0 4.5 5.0 60 70 80 90 100 110 rl=8 w rl=4 w rl=16 w gv = 2 cb = cin = 1f thd+n < 0.4% tamb = 25c snr (db) vcc (v) 2.5 3.0 3.5 4.0 4.5 5.0 50 60 70 80 90 rl=16 w rl=4 w rl=8 w gv = 10 cb = cin = 1f thd+n < 0.7% tamb = 25c snr (db) vcc (v) 2.5 3.0 3.5 4.0 4.5 5.0 60 70 80 90 100 rl=16 w rl=4 w rl=8 w gv = 10 cb = cin = 1f thd+n < 0.7% tamb = 25c snr (db) vcc (v) 012345 0 1 2 3 4 5 6 7 vstandby = 0v tamb = 25c icc (ma) vcc (v) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0 1 2 3 4 5 6 7 vcc = 5v tamb = 25c icc (ma) vstandby (v)
ts4871 18/28 fig. 75 : current consumption vs standby voltage @ vcc = 2.6v fig. 77 : clipping voltage vs power supply voltage and load resistor fig. 79 : vout1+vout2 unweighted noise floor fig. 76 : current consumption vs standby voltage @ vcc = 3.3v fig. 78 : clipping voltage vs power supply voltage and load resistor fig. 80 : vout1+vout2 a-weighted noise floor 0.0 0.5 1.0 1.5 2.0 2.5 0 1 2 3 4 5 6 vcc = 2.6v tamb = 25c icc (ma) vstandby (v) 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 tamb = 25 c rl = 16 w rl = 8 w rl = 4 w vout1 & vout2 clipping voltage high side (v) power supply voltage (v) 100 1000 10000 0 20 40 60 80 100 120 av = 10 av = 2 standby mode vcc = 2.5v to 5v, tamb = 25 c cb = cin = 1 f input grounded bw = 20hz to 20khz (unweighted) 20 output noise voltage ( v) frequency (hz) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0 1 2 3 4 5 6 vcc = 3.3v tamb = 25c icc (ma) vstandby (v) 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 tamb = 25 c rl = 16 w rl = 8 w rl = 4 w vout1 & vout2 clipping voltage low side (v) power supply voltage (v) 100 1000 10000 0 20 40 60 80 100 120 av = 10 av = 2 standby mode vcc = 2.5v to 5v, tamb = 25 c cb = cin = 1 f input grounded bw = 20hz to 20khz (a-weighted) 20 output noise voltage ( v) frequency (hz)
ts4871 19/28 application information fig. 81 : demoboard schematic fig. 82 : so8 & miniso8 demoboard components side 4 3 2 1 5 8 vin- vin+ - + - + bypass standby bias 6 vout1 vout2 av=-1 ts4871 vcc gnd vcc 7 + 470 s6 out1 s3 gnd s4 gnd s7 c10 + 470 c9 c7 100n c6 100 + r1 r2 c2 c1 c8 c12 1u c11 vcc r7 330k s8 standby d1 pw on r8 vcc s5 positive input mode r6 pos input p2 neg. input p1 c4 r5 r4 c5 r3 c3 gnd s2 vcc s1 vcc +
ts4871 20/28 fig. 83 : so8 & miniso8 demoboard top solder layer fig. 84 : so8 & miniso8 demoboard bottom solder layer n btl configuration principle the ts4871 is a monolithic power amplifier with a btl output type. btl (bridge tied load) means that each end of the load is connected to two single ended output amplifiers. thus, we have : single ended output 1 = vout1 = vout (v) single ended output 2 = vout2 = -vout (v) and vout1 - vout2 = 2vout (v) the output power is: for the same power supply voltage, the output power in btl configuration is four times higher than the output power in single ended configuration. n gain in typical application schematic (see page 1) in flat region (no effect of cin), the output voltage of the first stage is: for the second stage : vout2 = -vout1 (v) the differential output voltage is: the differential gain named gain (gv) for more convenient usage is: remark : vout2 is in phase with vin and vout1 is 180 phased with vin. it means that the positive terminal of the loudspeaker should be connected to vout2 and the negative to vout1. n low and high frequency response in low frequency region, the effect of cin starts. cin with rin forms a high pass filter with a -3db cut off frequency. in high frequency region, you can limit the bandwidth by adding a capacitor (cfeed) in parallel on rfeed. its form a low pass filter with a -3db cut off frequency. ) w ( r ) vout 2 ( pout l 2 rms = vout1 = vin C rfeed rin ------------------- - (v) vout2 vout1 = 2vin C rfeed rin ------------------- - (v) gv = vout2 vou t1 C vin -------------------------------------- - = 2 rfeed rin ------------------- - f cl = 1 2 p rin cin ------------------------------- - hz () f ch = 1 2 p rfeed cfeed ---------------------------------------------- - hz ()
ts4871 21/28 n power dissipation and efficiency hypothesis : ? voltage and current in the load are sinusoidal (vout and iout) ? supply voltage is a pure dc source (vcc) regarding the load we have: and and then, the average current delivered by the supply voltage is: the power delivered by the supply voltage is psupply = vcc icc avg (w) then, the power dissipated by the amplifier is pdiss = psupply - pout (w) and the maximum value is obtained when: and its value is: remark : this maximum value is only depending on power supply voltage and load values. the efficiency is the ratio between the output power and the power supply the maximum theoretical value is reached when vpeak = vcc, so n decoupling of the circuit two capacitors are needed to bypass properly the ts4871, a power supply bypass capacitor cs and a bias voltage bypass capacitor cb. cs has especially an influence on the thd+n in high frequency (above 7khz) and indirectly on the power supply disturbances. with 100f, you can expect similar thd+n performances like shown in the datasheet. if cs is lower than 100f, in high frequency increases, thd+n and disturbances on the power supply rail are less filtered. to the contrary, if cs is higher than 100f, those disturbances on the power supply rail are more filtered. cb has an influence on thd+n in lower frequency, but its function is critical on the final result of psrr with input grounded in lower frequency. if cb is lower than 1f, thd+n increase in lower frequency (see thd+n vs frequency curves) and the psrr worsens up if cb is higher than 1f, the benefit on thd+n in lower frequency is small but the benefit on psrr is substantial (see psrr vs. cb curve : fig.12). note that cin has a non-negligible effect on psrr in lower frequency. lower is its value, higher is the psrr (see fig. 13). n pop and click performance pop and click performance is intimately linked with the size of the input capacitor cin and the bias voltage bypass capacitor cb. size of cin is due to the lower cut-off frequency and psrr value requested. size of cb is due to thd+n and psrr requested always in lower frequency. moreover, cb determines the speed that the amplifier turns on. the slower the speed is, the softer the turn on noise is. the charge time of cb is directly proportional to v out = v peak sin w t (v) i out = v out r l ---------------- - (a) p out = v peak 2 2r l ---------------------- ( w ) i cc avg = 2 v peak p r l ------------------- - (a) p diss = 22vcc p r l ---------------------- p out p out (w) C ? pdiss ? p out --------------------- - = 0 ) w ( r vcc 2 max pdiss l 2 2 p = h = p out psupply ----------------------- - = p v peak 4v cc ----------------------- p 4 ---- - = 78.5%
ts4871 22/28 the internal generator resistance 50k w . then, the charge time constant for cb is t b = 50k w xcb (s) as cb is directly connected to the non-inverting input (pin 2 & 3) and if we want to minimize, in amplitude and duration, the output spike on vout1 (pin 5), cin must be charged faster than cb. the charge time constant of cin is t in = (rin+rfeed)xcin (s) thus we have the relation t in << t b (s) the respect of this relation permits to minimize the pop and click noise. remark : minimize cin and cb has a benefit on pop and click phenomena but also on cost and size of the application. example : your target for the -3db cut off frequency is 100 hz. with rin=rfeed=22 k w , cin=72nf (in fact 82nf or 100nf). with cb=1f, if you choose the one of the latest two values of cin, the pop and click phenomena at power supply on or standby function on/off will be very small 50 k w x1f >> 44k w x100nf (50ms >> 4.4ms). increasing cin value increases the pop and click phenomena to an unpleasant sound at power supply on and standby function on/off. why cs is not important in pop and click consideration ? hypothesis : ? cs = 100f ? supply voltage = 5v ? supply voltage internal resistor = 0.1 w ? supply current of the amplifier icc = 6ma at power on of the supply, the supply capacitor is charged through the internal power supply resistor. so, to reach 5v you need about five to ten times the charging time constant of cs ( t s = 0.1xcs (s)). then, this time equal 50s to 100s << t b in the majority of application. at power off of the supply, cs is discharged by a constant current icc. the discharge time from 5v to 0v of cs is: now, we must consider the discharge time of cb. at power off or standby on, cb is discharged by a 100k w resistor. so the discharge time is about t b disch ? 3xcbx100k w (s). in the majority of application, cb=1f, then t b disch ? 300ms >> t dischcs . n power amplifier design examples given : ? load impedance : 8 w ? output power @ 1% thd+n : 0.5w ? input impedance : 10k w min. ? input voltage peak to peak : 1vpp ? bandwidth frequency : 20hz to 20khz (0, -3db) ? ambient temperature max = 50c ? so8 package first of all, we must calculate the minimum power supply voltage to obtain 0.5w into 8 w . with curves in fig. 15, we can read 3.5v. thus, the power supply voltage value min. will be 3.5v. following the maximum power dissipation equation with 3.5v we have pdissmax=0.31w. refer to power derating curves (fig. 20), with 0.31w the maximum ambient temperature will be 100c. this last value could be higher if you follow the example layout shown on the demoboard (better dissipation). the gain of the amplifier in flat region will be: we have rin > 10k w . let's take rin = 10k w , then rfeed = 28.25k w . we could use for rfeed = 30k w in normalized value and the gain will be gv = 6. in lower frequency we want 20 hz (-3db cut off frequency). then: so, we could use for cin a 1f capacitor value t dischcs = 5cs icc ------------- - = 83 ms ) w ( r vcc 2 max pdiss l 2 2 p = g v = v outpp v inpp --------------------- = 22r l p out v inpp ----------------------------------- - = 5.65
ts4871 23/28 which gives 16hz. in higher frequency we want 20khz (-3db cut off frequency). the gain bandwidth product of the ts4871 is 2mhz typical and doesn't change when the amplifier delivers power into the load. the first amplifier has a gain of: and the theoretical value of the -3db cut-off higher frequency is 2mhz/3 = 660khz. we can keep this value or limit the bandwidth by adding a capacitor cfeed, in parallel on rfeed. then: so, we could use for cfeed a 220pf capacitor value that gives 24khz. now, we can calculate the value of cb with the formula t b = 50k w xcb >> t in = (rin+rfeed)xcin which permits to reduce the pop and click effects. then cb >> 0.8f. we can choose for cb a normalized value of 2.2f that gives good results in thd+n and psrr. in the following tables, you could find three another examples with values required for the demoboard. remark : components with (*) marking are optional. application n1 : 20hz to 20khz bandwidth and 6db gain btl power amplifier. components : application n2 : 20hz to 20khz bandwidth and 20db gain btl power amplifier. components : c in = 1 2 p rinf cl ------------------------------ = 795nf rfeed rin ----------------- = 3 c feed = 1 2 p r feed f ch -------------------------------------- - = 265pf designator part type r1 22k / 0.125w r4 22k / 0.125w r6 short cicuit r7 330k / 0.125w r8* (vcc-vf_led)/if_led c5 470nf c6 100f c7 100nf c9 short circuit c10 short circuit c12 1f s1, s2, s6, s7 2mm insulated plug 10.16mm pitch s8 3 pts connector 2.54mm pitch p1 pcb phono jack d1* led 3mm u1 ts4871id or ts4871is designator part type r1 110k / 0.125w r4 22k / 0.125w r6 short cicuit r7 330k / 0.125w r8* (vcc-vf_led)/if_led c5 470nf c6 100f c7 100nf
ts4871 24/28 application n3 : 50hz to 10khz bandwidth and 10db gain btl power amplifier. components : application n4 : differential inputs btl power amplifier. in this configuration, we need to place these components : r1, r4, r5, r6, r7, c4, c5, c12. we have also : r4 = r5, r1 = r6, c4 = c5. the gain of the amplifier is: for vcc=5v, a 20hz to 20khz bandwidth and 20db gain btl power amplifier you could follow the bill of material below. components : c9 short circuit c10 short circuit c12 1f s1, s2, s6, s7 2mm insulated plug 10.16mm pitch s8 3 pts connector 2.54mm pitch p1 pcb phono jack d1* led 3mm u1 ts4871id or ts4871is designator part type r1 33k / 0.125w r2 short circuit r4 22k / 0.125w r6 short cicuit r7 330k / 0.125w r8* (vcc-vf_led)/if_led c2 470pf c5 150nf c6 100f c7 100nf c9 short circuit c10 short circuit c12 1f s1, s2, s6, s7 2mm insulated plug 10.16mm pitch s8 3 pts connector 2.54mm pitch p1 pcb phono jack d1* led 3mm u1 ts4871id or ts4871is designator part type designator part type r1 110k / 0.125w r4 22k / 0.125w r5 22k / 0.125w r6 110k / 0.125w r7 330k / 0.125w r8* (vcc-vf_led)/if_led c4 470nf c5 470nf c6 100f c7 100nf c9 short circuit c10 short circuit c12 1f d1* led 3mm s1, s2, s6, s7 2mm insulated plug 10.16mm pitch s8 3 pts connector 2.54mm pitch p1, p2 pcb phono jack u1 ts4871id or ts4871is g vdiff = 2 r1 r4 ------- -
ts4871 25/28 n note on how to use the psrr curves (page 7) we have finished a design and we have chosen the components values : ? rin=rfeed=22k w ? cin=100nf ? cb=1f now, on fig. 13, we can see the psrr (input grounded) vs frequency curves. at 217hz we have a psrr value of -36db. in reality we want a value about -70db. so, we need a gain of 34db ! now, on fig. 12 we can see the effect of cb on the psrr (input grounded) vs. frequency. with cb=100f, we can reach the -70db value. the process to obtain the final curve (cb=100f, cin=100nf, rin=rfeed=22k w ) is a simple transfer point by point on each frequency of the curve on fig. 13 to the curve on fig. 12. the measurement result is shown on the next figure. fig. 85 : psrr changes with cb what is the psrr ? the psrr is the power supply rejection ratio. it's a kind of svr in a determined frequency range. the psrr of a device, is the ratio between a power supply disturbance and the result on the output. we can say that the psrr is the ability of a device to minimize the impact of power supply disturbances to the output. how do we measure the psrr ? fig. 86 : psrr measurement schematic n principle of operation ? we fixed the dc voltage supply (vcc), the ac sinusoidal ripple voltage (vripple) and no supply capacitor cs is used the psrr value for each frequency is: remark : the measure of the rms voltage is not a rms selective measure but a full range (2 hz to 125 khz) rms measure. it means that we measure the effective rms signal + the noise. n high/low cut-off frequencies for their calculation, please check this "frequency response gain vs cin, & cfeed" graph: 10 100 1000 10000 100000 -70 -60 -50 -40 -30 cin=100nf cb=100 m f cin=100nf cb=1 m f vcc = 5, 3.3 & 2.6v rfeed = 22k, rin = 22k rg = 100 w , rl = 8 w tamb = 25 c psrr (db) frequency (hz) vripple vcc rin cin rg 100 ohms cb rfeed 4 3 2 1 5 8 vin- vin+ - + - + bypass standby bias 6 vout1 vout2 av=-1 ts4871 vs- vs+ rl vcc gnd 7 psrr db () = 20 x log 10 rms v ripple () rms vs + - vs - () -------------------------------------------- - 10 100 1000 10000 -25 -20 -15 -10 -5 0 5 10 rin = rfeed = 22k w tamb = 25 c cfeed = 2.2nf cfeed = 680pf cfeed = 330pf cin = 470nf cin = 82nf cin = 22nf gain (db) frequency (hz)
ts4871 26/28 package mechanical data dim. mm. inch min. typ max. min. typ. max. a 1.35 1.75 0.053 0.069 a1 0.10 0.25 0.04 0.010 a2 1.10 1.65 0.043 0.065 b 0.33 0.51 0.013 0.020 c 0.19 0.25 0.007 0.010 d 4.80 5.00 0.189 0.197 e 3.80 4.00 0.150 0.157 e 1.27 0.050 h 5.80 6.20 0.228 0.244 h 0.25 0.50 0.010 0.020 l 0.40 1.27 0.016 0.050 k ? (max.) ddd 0.1 0.04 so-8 mechanical data 0016023/c 8
ts4871 27/28 package mechanical data
ts4871 28/28 package mechanical data information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result f rom its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specificati ons mentioned in this publication are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of stmicroelectronics. ? the st logo is a registered trademark of stmicroelectronics ? 2003 stmicroelectronics - printed in italy - all rights reserved stmicroelectronics group of companies australia - brazil - canada - china - finland - france - germany - hong kong - india - israel - italy - japan - malaysia malta - morocco - singapore - spain - sweden - switzerland - united kingdom - united states ? http://www.st.com

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