Headphone amplifier circuit TDA1308

Single chip microcomputer STM32L151CCU6

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ) 7.5PF 10PPM 20PPM 30PPM

MOS power IC full range

Crystal oscillator

TDA1308 is a Class A and B earphone power amplifier integrated circuit introduced by Philips. Its excellent performance makes the previous "classic" amplifiers such as TDA2822, TDA7050 and LM386 unmatched.
The common data is basically powered by a single power supply (3 to 7V). In fact, the TDA1308 is also a dual op amp. The pin function is exactly the same as that of the NE5532. However, it is difficult to use it to directly replace the common NE5532 and other operational amplifiers, because its working voltage is very low (up to ±3.5V), and the size is only 5.8mm × 4.8mm × 1.75mm. And its "disadvantages" and its extremely low power consumption (about 3mA quiescent current, about 5mA when working) and operating voltage (can be as low as ±1.2V, the sound quality can not be heard at this time) is undoubtedly made The preferred choice for miniature low voltage circuits such as stereo players and radios. Another advantage of the TDA1308 is its extremely high signal-to-noise ratio (up to 100dB). The actual audition shows that the signal-to-noise ratio is much better than that of the NE5532 and LF353.
The following describes the Hi-Fi stereo player made with the TDA1308. The circuit is shown below. One channel is used for each channel, and the two amplifying units serve as the front and power amplifiers respectively, which improves the separation of the channels, and the stereoscopic effect is very good. There is a lot of room for the selection of the motor's steady-speed circuit. As long as the working voltage is suitable, such as AN6650, KA2201, etc., it will not be introduced here. It should be pointed out that the TDA1308 uses the MOSFET as the input stage and the output stage. The input bias current can be almost ignored, which prevents the bias current from being too large and makes the head magnetized. This is also the op amp that uses the transistor as the input stage such as the NE5532. Not too late.
The circuit operates from dual supplies and can be selected from ±1.5V to ±3V. Since the coupling capacitor is omitted and the high signal-to-noise ratio of the TDA1308 makes the background noise almost inaudible, the sound quality is very clear and clear.
It may be because the TDA1308 has a low operating voltage and a small current. It always feels that its strength is slightly smaller, and it is slightly thinner. It is also a bit of a feeling of power when driving a slightly larger headphone. But its refreshing tone is still worth a "burn".