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I'm not following too well.. what is the exact motivation for including FM chips that are going to be disabled in the first place? What series of events lead t

I'm not following too well.. what is the exact motivation for including FM chips that are going to be disabled in the first place? What series of events lead to FM capable hardware being incidentally included, but disabled in modern smartphones?

mikepavone 9y ago
Pretty sure there's not a separate chip so much as it's built into one of the chips that's already used. Presumably it's built into those chips for markets in which FM radio support is considered important and it doesn't take up enough die space to be worth making an FM-less version.
ungzd 9y ago
Probably there are no separate "chips", but functionality built in into the same integrated circuit as CPU and other things (SoC). The reason to include it into SoC is that the same SoC is used in various devices, not only phones, and it's not so complicated thing, just heterodyne and ADC. Mainstream media loves the word "chip" and uses it in any context they like.
cesarb 9y ago
> what is the exact motivation for including FM chips that are going to be disabled in the first place? A single chip can do multiple things (WiFi, Bluetooth, FM, etc). For the chip manufacturer, it's simpler and cheaper to provide a single version of the chip with everything, and let the device manufacturer simply disable the unused parts, than to provide several different versions of the chip, some with FM and some without FM. That is, the phone manufacturer decides "I want Bluetooth and WiFi", and the chip they chose for that happened to also have FM. Since they won't use the FM part of the chip, they don't even have to connect the "FM antenna input" pin, saving the space on the board that would be used for the corresponding trace(s) and passive components (which they also don't have to install, reducing the costs).
phkahler 9y ago
You may want to read about software defined radio. It's quite possible that it's not even extra circuitry going unused. As the others say, it's so small the die area savings isn't even worth making a different variant of the chip.

mikepavone 9y ago

Pretty sure there's not a separate chip so much as it's built into one of the chips that's already used. Presumably it's built into those chips for markets in which FM radio support is considered important and it doesn't take up enough die space to be worth making an FM-less version.

ungzd 9y ago

Probably there are no separate "chips", but functionality built in into the same integrated circuit as CPU and other things (SoC). The reason to include it into SoC is that the same SoC is used in various devices, not only phones, and it's not so complicated thing, just heterodyne and ADC. Mainstream media loves the word "chip" and uses it in any context they like.

cesarb 9y ago

> what is the exact motivation for including FM chips that are going to be disabled in the first place? A single chip can do multiple things (WiFi, Bluetooth, FM, etc). For the chip manufacturer, it's simpler and cheaper to provide a single version of the chip with everything, and let the device manufacturer simply disable the unused parts, than to provide several different versions of the chip, some with FM and some without FM. That is, the phone manufacturer decides "I want Bluetooth and WiFi", and the chip they chose for that happened to also have FM. Since they won't use the FM part of the chip, they don't even have to connect the "FM antenna input" pin, saving the space on the board that would be used for the corresponding trace(s) and passive components (which they also don't have to install, reducing the costs).

phkahler 9y ago

You may want to read about software defined radio. It's quite possible that it's not even extra circuitry going unused. As the others say, it's so small the die area savings isn't even worth making a different variant of the chip.