Analogue LM4861 Audio amplifier and interface PCB
Budget: $15 – $25 AUD
PIC18F14K22 provides interface logic
The version LVC TV Interface 1711ver4 had problems of stability apparently due to the PTC thermal fuse.
So it was decided to revert to LM4861 audio and supplied by 5VDC.
1. Change U4 to 7808 same footprint L7805CDT-TR v1.5A 2V@(1A) Fixed 5V~5V Positive 1 35V TO-252-3 Linear Voltage Regulators (LDO)
2. Add 3.3V regulator type LP2981-33DBVR 100mA 375mV@(100mA) Fixed 3.3V~3.3V Positive 1 16V SOT-23-5 Linear Voltage Regulators (LDO):
3.3V is fir PIC and logic supply
5V DC is ONLY for the Audio amplifier.
3. Remove U2 (BA3121F-E2) and associated components
4. Remove U3 (TDA2822D) and associated components
5. Add LM4861 audio amplifier 8-Lead package D SOIC in place of TD2822D
5. Remove FB1 and net AGND
The version LVC TV Interface 1711ver4 had problems of stability apparently due to the PTC thermal fuse.
So it was decided to revert to LM4861 audio and supplied by 5VDC.
1. Change U4 to 7808 same footprint L7805CDT-TR v1.5A 2V@(1A) Fixed 5V~5V Positive 1 35V TO-252-3 Linear Voltage Regulators (LDO)
2. Add 3.3V regulator type LP2981-33DBVR 100mA 375mV@(100mA) Fixed 3.3V~3.3V Positive 1 16V SOT-23-5 Linear Voltage Regulators (LDO):
3.3V is fir PIC and logic supply
5V DC is ONLY for the Audio amplifier.
3. Remove U2 (BA3121F-E2) and associated components
4. Remove U3 (TDA2822D) and associated components
5. Add LM4861 audio amplifier 8-Lead package D SOIC in place of TD2822D
5. Remove FB1 and net AGND