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5.10 U17/U18
The RC4558 is dual general-purpose operational amplifiers with each half electrically similar to
the uA741 except that offset null capability is not provided.
Block Diagram (each amplifier)
5.11 U16
YDA138 is a high efficient digital audio power amplifier IC that operates with a single 12V
power supply. An audio power amplifier with a maximum output of 10W (RL=8ohm)*2ch or
20W(RL=4ohm)*1ch can be configured with one chip.
YDA138 has a”Pure Pulse Direct Speaker Drive Circuit” which directly drives speakers while
reducing distortion of pulse output signal and reducing noise on the signal.and realizes the highest
standard low distortion rate characteristics and low noise characteristics as 10W-class of output
digital amplifier IC.
YDA138 has 20mW(RL=32ohm)*2ch class AB headphone amplifiers.
YDA138 provides Over-current protection function for speaker output terminals,IC thermal
protection function,POP noise reduction function,and AM interference measures function as well
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