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ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 1 ? features ? 2.0v~5.5v power supply. ? thermal shutdown protection. ? low current shutdown mode ? no output capacitors and networks or bootstrap capacitors required ? low noise during turn-on and turn-off transitions ? lead free and green package available. (rohs compliant) ? space saving package -- 8-pin msop package. application ? portable electronic devices ? mobile phones ? pdas general description the ly8891 is a 2.0w audio power amplifier. it is capable of driving 4 speaker load at a continuous average output of 2.0w with less than 10% distortion (thd+n) from a 5.5v power supply and 8 speaker load at a conti nuous average output of 1.4w with less than 10% distortion (thd+n) from a 5.0v power supply. the ly8891 primarily designed for high quality application in other portable communication device. and the ly8891 audio amplifier features low power consumption shutdown mode. it is achieved by driving the shutdown pin with logic low. and the ly8891 has an internal thermal shutdown protection feature. the ly8891 audio amplifier was designed specifically to provide high quality output power with a minimal amount of external components. the ly8891 does not require output capacitors, and the ly8891 is ideally suited for other low voltage applications or portable electronic devices where minimal power consumption is a primary requirement. pin configuration msop8
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 2 ? pin description symbol pin no. description msop8 shutdown 1 shutdown the device. (when low level is shutdown mode) bypass 2 bypass pin +in 3 positive input -in 4 negative input vo1 5 negative output v dd 6 power supply gnd 7 ground vo2 8 positive output ordering information ordering code packing type speaker channels pin/ package output power (thd+n=10%) input type output type ly8891ult tape & reel mono msop8 2.0w/4 ? @5.5v_btl 1.8w/4 ? @5.0v_btl 1.7w/8 ? @5.5v_btl 1.4w/8 ? @5.0v_btl se/ df btl
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 3 ? application circuit figure 1. ly8891 a pplication schematic wi th single ?ended input figure 2. ly8891 a pplication schematic wi th differential input
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 4 ? absolute maximum ratings parameter symbol rating unit supply voltage v dd 6.0 v operating temperature t a -40 to 85 (i grade) input voltage v i -0.3v to v dd +0.3v v storage temperature t stg -65 to 150 power dissipation p d internally limited w esd susceptibility v esd 2000 v junction temperature t jmax 150 soldering temperature (under 10 sec) t solder 260 dc electrical characteristics (v dd =5.0v, t a =25 ) parameter symbol test condition min. typ. *1 max. unit power supply current i dd v i n = 0v, i o = 0a, 8 load - 5.0 15.0 ma shutdown current i sd v shutdow n = 0v - 0.1 2.0 a shutdown voltage input high v sdih v sd mode = v dd 1.2 - - v shutdown voltage input low v sdil v sd mode = gnd - - 0.4 output offse t voltage v os - 7.0 50.0 mv resistor output to gnd r out-gnd - 9.5 - k output power po thd = 10% , f = 1 khz r l =4 ? (at 5.5v) - 2.0 - w thd = 10% , f = 1 khz r l =4 ? (at 5.0v) - 1.8 - thd = 1% , f = 1 khz r l =4 ? (at 5.0v) - 1.4 - thd = 10% , f = 1 khz r l =8 ? (at 5.5v) - 1.7 - thd = 10% , f = 1 khz r l =8 ? (at 5.0v) - 1.4 - thd = 1% , f = 1 khz r l =8 ? (at 5.0v) - 1.0 - total harmonic distortion+ noise thd+n po = 635 mwrms; f = 1khz - 0.1 % power supply rejection ratio psrr vripple = 200mv sine p-p, input with floating. - 66 (f = 217hz) 66 (f = 1khz) - db wake-up time t wu bypass cap.=1.0uf, 5.0v - 145 ms thermal shutdown temperature t sd 150 170 190 shut down time t sdt 8 ? load 1.0 ms (*1)typical values are included for reference only and are not guaranteed or tested. typical values are measured at vcc = vcc(typ.) and ta = 25
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 5 ? dc electrical characteristics (v dd =3.6v, t a =25 ) parameter symbol test condition min. typ. *1 max. unit power supply current i dd v i n = 0v, i o = 0a, 8 load - 4.5 14.0 ma shutdown current i sd v shutdow n = = 0v - 0.1 2.0 a shutdown voltage input high v sdih v sd mode = v dd 1.2 - - v shutdown voltage input low v sdil v sd mode = gnd - - 0.4 output offse t voltage v os - 7.0 50.0 mv resistor output to gnd r out-gnd 7.0 8.5 9.7 k output power po thd = 10% , f = 1 khz r l =4 ? - 900 - mw thd = 1% , f = 1 khz r l =4 ? - 700 - thd = 10% , f = 1 khz r l =8 ? - 700 - thd = 1% , f = 1 khz r l =8 ? - 550 - total harmonic distortion+ noise thd+n po = 280 mw rms , f = 1khz - 0.11 - % power supply rejection ratio psrr v ripple = 200mv sine p-p, input with floating. - 62 (f = 217hz) 62 (f = 1khz) - db wake-up time t wu -82 ms thermal shutdown temperature t sd 150 170 190 (*1)typical values are included for reference only and are not guaranteed or tested. typical values are measured at vcc = vcc(typ.) and ta = 25
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 6 ? typical performanc e characteristics figure 3 thd+n vs frequency (at rl=8 ? , av=2) figure 4 thd+n vs frequency (at rl=4 ? , av=2)
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 7 ? figure 5 thd+n vs power out (@ rl=8 ? , f=1khz, a v =2) figure 6 thd+n vs power out (@ rl=4 ? , f=1khz, a v =2)
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 8 ? figure 7 power supply rejection ratio (psrr) (@ rl=8 ? , av=2, vripple = 200mvp-p, rin = floating)
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 9 ? application information bridged configu ration explanation as shown in figure 1, the ly8891 has two operational amplifiers internally, allowing for a few different amplifier configurations. the first amplifier?s gain is externally configurable, while the second amplifier is internally fixed in a unity-gain, inverting configuratio n. the closed-loop gain of the first amplifier is set by selecting the ratio of rf to rin while the second amplifier?s gain is fixed by the two internal 20k ? resistors. figure 1 shows that the output of amplifier one serves as the input to amplifier two which results in both amplifiers producing signals identical in magnitude, but out of phase by 180. consequently, the differential gain for the ic is avd= 2 x ( r f / r in ) ????????????????????????(1) by driving the load differentially through outputs vo1 and vo2, an amplifier configuration commonly referred to as ?bridged mode? is established. bridged mode oper ation is different from the classical single-ended amplifier configuration where one side of the load is connected to ground. a bridge amplifier design has a few distinct advantages ov er the single-ended configur ation, as it provides differential drive to the load, thus doubling output swin g for a specified supply voltage. four times the output power is possible as compared to a single-ended amplifier under the same conditions. this increase in attainable output power assumes that the amplifier is not current limited or clipped. in order to choose an amplifier?s closed-loop gain without causing ex cessive clipping, please refer to the audio power amplifier design section. a bridge configuration, such as the one used in the ly8891, also creates a second advantage over single -ended amplifiers. since the differential outputs, vo1 and vo2, are biased at half-supply, no net dc voltage exists across the load. this eliminates the need for an output coupling capacitor which is required in a single supply, single-ended amplifier configuration. without an output coupling capacitor, the half-supply bias across the load would result in both increased internal ic power dissipation and also possible loudspeaker damage. input capacitors (ci) the ly8891 input capacitors and input resistors form a high-pass filter with the corner frequency, f c , determined in equation equation 2. 1 fc = -------- --------????????????????????????(2) 2 rici equation 3 is reconfigured to solve for the input coupling capacitance. 1 ci = ---------- -------???????????????????????.(3) 2 rifc for example in the table 1 shows the external components. rin in connect with cin to create a high-pass filter. table 1. typical component values reference description note ri 20k ? 1% tolerance resistors ci 0.39uf 80%/?20%
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 10 ? ci = 1 / ( 2 rifc) ci = 1 / ( 2 x20k ? x20hz)=0.397uf use 0.39uf power supply bypassing as with any amplifier, proper supply bypassing is cr itical for low noise performance and high power supply rejection. the capacitor location on both the bypass and power supply pins should be as close to the device as possible.
ly8891 rev. 1.8 2.0 watt audio power amplifier lyontek inc. reserves the rights to change the specifications and products without notice. 2f, no. 17, lndustry e . rd. ii, science-bas ed industrial park, hsinchu 300, taiwan tel: 886-3-6668838 fax: 886-3-6668836 11 ? package outline dimension 8 pin msop package outline dimension

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