22721 chip " Probably the TLC22721 chip. The TLC22721 is a dual-channel low-noise rail-to-rail operational amplifier chip manufactured by Texas Instruments. It is an operational amplifier (operational amplifier) used in circuits for signal amplification and processing. Regarding its power supply, the TLC22721 chip is usually powered by a dual power supply, that is, a positive power supply and a negative power supply. The positive power supply is generally connected to the V pin of the chip, and the negative power supply is connected to the V- pin. The specific power supply voltage range and operating conditions can be referred to the data manual or specifications of the chip.
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The 22721 chip is a variable frequency power supply