unisonic technologies co.,ltd. tea2025a linear integrated circuit www.unisonic.com.tw 1 of 8 copyright ? 2014 unisonic technologies co.,ltd. qw-r107-012.c stereo audio amplifier ? description the utc tea2025a is a monolithic integrated circuit, consisting of a 2-channel power am plifier. it is suitable for stereo and bridge amplifier application of radio cassette tape recorders. ? features * high output power stereo: po=2.3w (typ) at vcc=9v, r l =4 ? bridge: po=4.7w (typ) at vcc=9v, r l =8 ? * low switching distortion at high frequency * small shock noise at the time of power on/off dur to a built-in muting circuit * good ripple rejection due to a built-in ripple filter * good channel separation * soft tone at the time of output straiten * closed loop voltage gain fixed 45db (bridge: 51db) but availability with external resistor added * minimum number of external parts required * easy to design radiator fin ? ordering information order number package packing tea2025ag-d12-h-t dip-12h tube ? marking
tea2025a linear integrated circuit unisonic technologies co., ltd 2 of 8 www.unisonic.com.tw qw-r107-012.c ? pin configuration btl out out 2 b.s.2 nf2 in 2 dc v cc out 1 b.s.1 nf1 in 1 pre gnd 1 2 3 4 5 6 7 11 12 8 9 10 ? block diagram
tea2025a linear integrated circuit unisonic technologies co., ltd 3 of 8 www.unisonic.com.tw qw-r107-012.c ? absolute maximum ratings (t a =25c, unless otherwise specified) parameter symbol ratings unit supply voltage v s 15 v power dissipation p d 4 w operating temperature t opr -20~+70 ? c storage temperature t stg -40~+150 ? c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? electrical characteristics (t a =25c, r g =600v, stereo, unless otherwise specified.) parameter symbol test conditions min typ max unit operating supply voltage v cc 3 12 v quiescent current i cc vi=0, stereo 40 50 ma closed loop voltage gain a v stereo, vi=-45dbm 43 45 47 db bridge, vi=-45dbm 49 51 53 db channel balance c b stereo -1 0 +1 db output power p o stereo, r l =4 ? , thd=10% 1.7 2.3 w stereo, r l =8 ? , thd=10% 1.3 w bridge, r l =8 ? , thd=10% 4.7 w total harmonic distortion t hd stereo, po=250mw, r l =4 ? 0.3 1.5 % bridge, po=250mw, r l =4 ? 0.5 % input resistance r i 21 30 k ? rijpple rejection r r stereo, rg=0 ? , vr=150mv, f=100hz 40 46 db output noise voltage v no stereo, rg=0 ? 1.5 3 mv stereo, rg=10k ? 3 6 mv cross-talk c t stereo, rg=10k ? , vo=0dbm 40 55 db
tea2025a linear integrated circuit unisonic technologies co., ltd 4 of 8 www.unisonic.com.tw qw-r107-012.c ? application in formation stereo amplifier bridge amplifier input 789 654 10 11 12 321 + 100/16v c1 + + + + + + + + + c2 470/16v c4 c3 0.15 c5 100/16v 100f r l vcc c7 0.15 c6 470/16v polyester film capacitor c8 100/16v c9 100/16v c10 100/16v fin fin utc tea2025a 0.22 f
tea2025a linear integrated circuit unisonic technologies co., ltd 5 of 8 www.unisonic.com.tw qw-r107-012.c ? application information input capacitor input capacitor is pnp type allowing source to be referenced to ground. in this way no input coupling capacitor is required. however, a series capacitor (0.22 uf)to the input side can be useful in case of noise due to variable resistor contact. bootstrap the bootstrap connection allows to in crease the output swing. the suggest ed value for the bootstrap capacitors (100uf) avoids a reduction of the output signal also at low frequencies and low supply voltages. voltage gain adjust stereo mode (figure 1) the voltage gain is determined by on-chip resistors r1 and r2 together with the extern al rfc1 series connected between pin 6 (11) and ground. the frequency response is given approximated by: with r f =0, c 1 =100 f, the gain results 46 db with pole at f=32 hz. the purpose of rf is to reduce the gain. it is recommended to not reduce it under 36 db. c1 r f 6 (11) r 2 r 1 2 (15) figure 1 bridge mode (figure 2) the bridge configuration is realized very easily thanks to an internal voltage divider which provides (at pin 1) the ch 1 output signal after reduction. it is enough to connect pin 6 (i nverting input of ch 2) with a capacitor to pin 1 and to connect to ground the pin 7. the total gain of the bridge is given by: and with the suggested values (c1 = c2 = 100 uf, r f = 0) means: gv = 52 db with first pole at f = 32 hz
tea2025a linear integrated circuit unisonic technologies co., ltd 6 of 8 www.unisonic.com.tw qw-r107-012.c ? application information(cont.) out in r1 r1 r2 r2 r4 r3 out figure 2 output capacitors the low cut off frequency due to output capacitor depending on the load is given by: with c out 470uf and r l = 4 ohm it means f l = 80hz. pop noise (figure 3) most amplifiers similar to utc tea2025a need external resistors between dc outputs and ground in order to optimize the pop on/off performance and crossover distortion. out 800 figure 3 the utc tea2025a solution allows to save components because of such resistors (800 ohm) are included into the chip. stability a good layout is recommended in order to avoid oscillation s. generally the designer must pay attention on the following points: - short wires of components and short connections. - no ground loops. - bypass of supply voltage with capacitors as nearest as po ssible to the supply i. c. pin. the low value (poliester) capacitors must have good temperat ure and frequency characteristics. - no sockets. the heatsink can have a smaller factor of safety compared with that of a conventiona l circuit. there is no device damage in the case of excessive junction temperature: all that happens is that p o (and therefore p tot ) and id are reduced.
tea2025a linear integrated circuit unisonic technologies co., ltd 7 of 8 www.unisonic.com.tw qw-r107-012.c ? typical characteristics utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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