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In this video we're going to learn about the RF power amplifier chips
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The RF power amplifier chip, also known as the power amplifier chip,
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will be identified as PA in the drawings
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The main purpose of the RF power amplifier chip
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is to amplify the signal received or transmitted by the mobile phone
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when we make and receive a call
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For example, when we climb the mountain,
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the signal is weak,
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but the mobile phone can still receive the phone signal
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If the amplifier is damaged,
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we might not get a signal,
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and we might not be able to make or receive calls
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In Apple's machines, there are many power amplifier chips
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Why?
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Because Apple's machines support more frequency bands
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What is a frequency band?
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When you make and receive calls,
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the lines you use are called frequency bands,
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such as China Mobile, China Unicom and China Telecom,
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which have 2G, 3G and 4G lines
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Every line has a receiving signal and a transmitting signal,
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a line belongs to a frequency band
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There are many countries in the world,
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the total carrier frequency band will be about 30 bands
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Apple's machine is a global machine,
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it will be more than 30 frequency bands into the phone
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But some frequencies overlap
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A line might go through one or two chips
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So in Apple mainboards, there are a lot of these power amplifier chips
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These power amplifier chips are divided into low-frequency power amplifier,
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mainly responsible for 2G calls
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The other one is an intermediate frequency amplifier, like 3G
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Another is the high frequency power amplifier, such as 4G, 5G
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Different circuits pass through different power amplifier chips
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So there are a lot of power amplifier chips in Apple mainboards
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Like this xr mainboard, there will be 6 power amplifier chips,
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and these chips that I marked are all power amplifier chips
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In Android, there are fewer power amplifier chips
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Why?
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Because Android phone is sold in the domestic machine,
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it only does the domestic China Mobile, China Unicom, and China Telecom operators lines
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There are only a few lines in all
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So sometimes a power amplifier chip is all you need
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The main function of power amplifier chip is to play the role of signal amplification when receiving phone calls
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If it is damaged, it will result in no service, poor signal
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When the power amplifier chip is damaged and replaced,
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we need the same model to replace it
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Power amplifier chip surface for silver, rectangular mostly
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Like these chips we just saw,
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the surface is silver white, and rectangular
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These are all power amplifier chips
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Let's go to the mainboard to know the power amplifier chip
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The mainboard is an iPhone 7 mainboard,
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and its power amplifier chip is usually in the lower half
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We have three here, and we'll have two or three more on the opposite side
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There will be two more at the top of the mainboard
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Like this one with a silver surface,
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we can consider it as a power amplifier chip
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Because power amplifier is divided into low frequency,
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medium frequency and high frequency power amplifier
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This mainboard is an iPhone 8p Qualcomm baseband
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There are three power amplifier chips under the SIM card slot
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All three are power amplifier chips
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There is also a small power amplifier on the reverse side of the mainboard
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and two power amplifier chips on the top
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This is the mainboard of the iPhone 11
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The power amplifier chip of the dual-layer mainboard is usually located in the lower layer of the mainboard
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The upper layer will also have a few chips
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And when we layer it,
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we can see that there are two of them on top
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These two chips are called the power amplifier chips
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On the lower layer we can see that there are three of them here
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These chips are power amplifier chips
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So that's all for this lesson
