This part is a kind of semiconductor called RSN311W64B-P.

Function of this product has Power HIC.

Manufacturers : ETC

Image and pinout :

Some of the text within the PDF file :

IC501 RSN311W64B-P POWER HIC + + + + - POWER CONTROL CIRCUIT DISP HMUT POWER CONTROL/PROTECTION CIRCUIT -VCC LOW +DI SENS +VCC LOW 26 (25) 22 23 18 (19) 15 20 3 6 D501 1 (2) 8 12(11) 5 24 13 9 14 7 21 4 16 B B B B B Q506 INTERFACE SWITCH D502 TO MAIN BLOCK (JK2000) OF SA-HT720GCPS Q505 SWITCHING A SL(R) FILTER -DI SENS +VCC HI SL_O(R) FL_O(R) FLIN(R) IN GND SUB_O SUBIN AC IN C_O +VD -VD CIN -VCC HI SLIN(R) IH DET JK501(JK502) SURROUND SPEAKER C FILTER JK502 CENTRE SPEAKER FILTER SUBWOOFER FL(R) FILTER Q512 JK501 FRONT SPEAKER B Q501, Q502 DC_DET SWITCH D597 VOLTAGE REGULATOR T501 IC502 C0AABB000055 SW D508 Q513, Q514 DC DET SWITCH Q552~Q557 FAN MOTOR DRIVE B POWER TRANSFORMER S500 B DUAL LOW-NOISE OP AMP Q520 VOLTAGE SELECT [ ... ]

RSN311W64B-P PDF Datasheet Download