november 2006 rev 3 1/5 AN1766 application note ts4990 low voltage audio power amplifier evaluation board user guidelines ts4990 features ts4990 low voltage audio power amplifier with active low standby mode operating from v cc =2.2v to 5.5v 1.2w output power @ v cc =5v, thd=1%, f=1khz, with 8 load ultra low power consumption in standby mode (10na) 62db psrr @ 217hz in grounded mode (av=2v/v) near zero pop & click ultra low distortion (0.1%) module gain set at 2v/v thermal and short circuit protection description the demo ts4990 is an evaluation board designed for the ts4990 low power audio amplifier. the micropackage dfn8 (dual flat non leaded 8 pins) allows space saving and good thermal dissipation. the btl gain is set at 2v/v and can be adapted if necessary with a modification of r1 or r2 values. on the board, r3 and c3 component locations are empty to allow you to modify the input configuration from single ended to differential. for differential mode, r4 must be modified. the c1 component location is also empty so that you can add a low pass filter if required. more information about component calculations is available in the ts4990 datasheet. www.st.com
connector configuration AN1766 2/5 connector configuration caution: when you apply power supply through cn1, do not invert the polarity because it would destroy the amplifier u1. figure 1. schematic diagram connector description cn1 power connector (v cc and gnd). power supply voltage from 2.2v to 5.5v. cn2 and cn3 input signal connector (gnd and active input signal). cn4 output signal connector (v out1 and v out2 ). cn5 standby control connector (v cc , standby, gnd). a short-circuit between v cc and standby puts u1 in operation mode. a short-circuit between gnd and standby puts u1 in standby mode.
AN1766 component list for the demo ts4990/dfn 3/5 component list for the demo ts4990/dfn designation quantity description c1 0 unconnected, ceramic capacitors, 0603 c2 1 100nf/16v, ceramic capacitors, 0603 c3 0 unconnected, ceramic capacitors, 0603 c4 1 1 f/50v, electrolytic capacitor c5 1 100nf/16v, ceramic capacitors, 0603 c6 1 1 f/50v, electrolytic capacitor cn1 1 2 pins header 2.54mm pitch cn2 1 2 pins header 2.54mm pitch cn3 1 2 pins header 2.54mm pitch cn4 1 2 pins header 2.54mm pitch cn5 1 3 pins header 2.54mm pitch j1 1 jumper, 2.54mm pitch r1 1 22k, 1/16w 1% resistor, 0603 r2 1 22k, 1/16w 1% resistor, 0603 r3 0 unconnected, 1/16w 1% resistor, 0603 r4 1 0r, 1/16w 1% resistor, 0603 u1 1 ts4990iq (dfn8 package)
evaluation board layout AN1766 4/5 evaluation board layout the following schematics show the different layers and the top view of the evaluation board. figure 2. pcb top layer view figure 3. pcb bottom layer view figure 4. top view of demo board
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