the AMIS-14935 (former msc-lx1792) offers a patent pending, low-voltage, low-power and high efficiency amplifier for driving a high impedance speaker such as a hearing aid receiver or a headset. the AMIS-14935 consists of a pre-amplifier followed by a fixed gain class d amplifier. the input resistor and feedback resistor is external in the AMIS-14935 making it possible to set the gain arbitrarily, up to approximately 40db. the feedback resistor can also be potentiometer to facilitate volume control. AMIS-14935 audio amplifier description ?low operating current: 120? typical ?low operating voltage: 0.9v minimum ?gain set by external resistors ?3 output switch resistance settings: 48, 24 & 16 ? ?5?rms input referred noise key features ?hearing aid applications ?high impedance speaker/transducer applications important: for the most current data, consult ami semiconductor? website: http://www.amis.com. applications product highlight package order info ami semiconductor 1 www.amis.com note for hearing aid applications are covered by knowles patents numbers us 4,592,087 & 4,689,819: ami semiconductor policy is not to sell the AMIS-14935 into hearing aid applications unless a patent license exist between customer and knowles corporation. please contact amis for assistance with this. t j (?): 10?5 j: ceramic dip 14-pin nqfp: plastic mlpm 8-pin bd: bare die
input logic supply voltage (v dd )-0. 3v to +3.0v operating temperature range 10? to 55? note: exceeding these ratings could cause damage to the device. all voltages are with respect to ground. currents are positive into, negative out of specified terminal. AMIS-14935 audio amplifier absolute maxium ratings package pin out settings functional pin description ami semiconductor 2 www.amis.com package (top view) package (top view) pin imp sel =v ss imp sel =v dd imp sel =floating imp sel 16 ? 24 ? 48 ? pin name pin no pin no description 14 pin j 8 pin (evaluation samples) v dd 13 8 supply voltage v ss 21 ground in 8 5 analog audio input out p 14 7 positive output voltage out n 12 negative output voltage preout 9 6 pre-amplifier output imp sel 63 output resistance select. see settings table below for selections.
AMIS-14935 audio amplifier recommended operating conditions electrical characteristics ami semiconductor 3 www.amis.com unless otherwise specified, the following specifications apply over the operating ambient temperature t a =25? except where otherwise noted. test conditions: v dd =1.3v, v ss =0v, circuit connected as application schematic on page 5, output loaded with 200ohm in series with 60mh. parameter symbol test conditions AMIS-14935 units min typ max operating conditions supply voltage v dd 0.9 1.5 v ground v ss 0v parameter symbol test conditions AMIS-14935 units min typ max switch output resistance @ low drive r out-l 48 switch output resistance @ med drive r out-m 24 ? switch output resistance @ high drive r out-hi 16 19 quiescent current @ low drive iddq l 110 quiescent current @ med drive iddq m no load 120 ? quiescent current @ high drive iddq h 130 3db bandwidth ? min frequency f min r1=50k, r2=1000k, fin=1khz 40 100 hz 3db bandwidth ? max frequency f max 10 khz output switching frequency f clk 200 khz gain1 a 1 r1=50k, r2=500k 32 r1=25k, r2=500k 37 db power supply input reference rejection ratio psrr r1=50k, r2=500k 45 db total harmonic distortion thd1 r1=50k, r2=500k, vin=5mvrms, fin=1khz 0.3 r1=25k, r2=500k, vin=5mvrms, fin=1khz 0.5 % r1=50k, r2=500k, 100hz-10khz, no weighting 4 input referred noise v n-20 r1=25k, r2=500k, 100hz-10khz, ?rms no weighting 3 output clock frequency f clk 140 200 300 khz max absolute dc offset outn-outp v off-np no input signal 0 0.5 5 mv
AMIS-14935 audio amplifier charts ami semiconductor 4 www.amis.com note: graphs show distortion with no load outputs.
AMIS-14935 audio amplifier ami semiconductor 5 www.amis.com figure 2 ?h-bridge impedance vs. supply voltage (lowest impedance setting).
AMIS-14935 audio amplifier mechanicals - 8 pin mlpq package outline ami semiconductor 6 www.amis.com lm 8-pin plastic mlp-micro exposed pad j 14-pin ceramic dip note: 1. dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm (.006? on any side. lead dimension shall not include solder coverage. dim millimeters inches min max min max a 2.90 3.10 0.114 0.122 b 2.90 3.10 0.114 0.122 c 0.65 0.75 0.025 0.029 d 0.15 0.25 0.005 0.009 e 1.841 bsc 0.075 bsc f 0.27 0.43 0.010 0.016 g 0.65 bsc 0.025 bsc h 1.22 bsc 0.048 bsc i0 0.10 0 0.003 j 0.21 0.37 0.008 0.014 k0 0.10 0 0.003 dim millimeters inches min max min max a 19.30 19.94 0.760 0.785 b 5.59 7.11 0.220 0.280 c- 5.08 - 0.200 d 0.38 0.51 0.015 0.020 f 1.02 1.77 0.040 0.070 g 2.54 bsc 0.100 bsc h- 2.03 - 0.080 j 0.20 0.38 0.008 0.015 k 3.18 5.08 0.125 0.200 l 7.37 7.87 0.290 0.310 m-15 - 15
AMIS-14935 audio amplifier ami semiconductor 7 www.amis.com mechanicals - 7 pin bare die note: 1. dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm (.006? on any side. lead dimension shall not include solder coverage. dim millimeters inches min max min max x 1.15 0.045 y 1.78 0.070
AMIS-14935 audio amplifier using AMIS-14935 in hearing assist applications ami semiconductor 8 www.amis.com notes: 1. when using volume control potentiometer, keep input resistor between 25kohm to 50kohm for optimum performance. using lower than 25k may cause higher distortion and using higher than 50k may cause output noise to increase. 2. input coupling capacitor (c2) must be present. forms a high pass filter together with resistor r1 with an approximate corner frequency of 1/(2*3.14*r1*c2). 3. r2 and c3 facilitate supply filtering for microphone. the suggested values are indications only and are dependent on microphone characteristic, quality of supply and supply rejection needed. 4. bypass capacitor may or may not be needed. shall be kept low (less than 1?) since a high value capacitance supply to ground may cause audible noise at power down. 5. impsel pin (impedance select) should generally be tied to ground for minimum switch impedance and maximum drive capability. AMIS-14935
AMIS-14935 audio amplifier using AMIS-14935 as receiver driver in h-aid ultra low power audio system notes: 1. for optimum noise and distortion performance a 50k input resistor is recommended. 2. input coupling capacitor (c2) must be present. forms a high pass filter together with resistor r1 with an approximate corner frequency of 1/(2*3.14*r1*c2). 3. bypass capacitor (c1) may or may not be needed dependent on the supply quality. this capacitor shall have a low value (less than 1?) since a high value capacitance supply to ground may cause audible noise at power down. if other parts of the system requires a higher capacitor value this capacitor can be placed on the battery side of the switch making the total stored charge on the supply line small when system is powered down (switch is opened). ?copyright 2003 ami semiconductor ?all rights reserved. information furnished is believed to be accurate and reliable. howeve r, ami semiconductor assumes no responsibility for errors or omissions in the information and for the consequences of use of such information. ami semiconductor reserves the right to change the information contained herein at any time without notice. this information is provided ?s is?without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability, fitness for a particular purpose, or non-infringement of intellectual property. all title and intellectual property rights including, without limitation, copyrights, trademarks, in and to this information an d products are owned by ami semiconductor, and are protected by applicable laws. no license under any patent or other intellectual property of ami semiconductor is granted, by implication, estoppel or otherwise. ami semiconductor www.amis.com AMIS-14935
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