Published on October 17th, 2017 | by Alan Cross2
Explaining the Confusion Surrounding the (Phantom) FM Chip in iPhones
In the aftermath of two horrible hurricanes that knocked out power, Internet and cell service to millions of people, the one communications medium that kept running was old-fashioned radio. Without AM and FM station broadcasting on their emergency power supplies, vast swaths of the population would be have been left in the dark. Literary.
Once the storm passed, there were once again calls for telcos and handset manufacturers to turn on the FM chip that’s embedded in every mobile phone. Allegedly embedded. This included Ajit Pai, the head of the FCC.
“Apple is the one major phone manufacturer that has resisted [activating the chips]. But I hope the company will reconsider its position, given the devastation wrought by Hurricanes Harvey, Irma, and Maria.”
Fantastic. All for it except that not all handsets have FM chips, including late model, have that capability. Apple had to point out that iPhone 7s and 8s don’t have FM chips nor do they have any antennae to support reception of FM broadcasts.
“Apple cares deeply about the safety of our users, especially during times of crisis and that’s why we have engineered modern safety solutions into our products. Users can dial emergency services and access Medical ID card information directly from the Lock Screen, and we enable government emergency notifications, ranging from Weather Advisories to AMBER alerts. iPhone 7 and iPhone 8 models do not have FM radio chips in them nor do they have antennas designed to support FM signals, so it is not possible to enable FM reception in these products.”
First of all, there isn’t really a physical chip in any of these phones. It’s a software-defined radio. The antenna on phones that do have FM radios are the headphones. (Oops. Apple has done away with the headphone jack, so that’s out…)
Previously, just about everyone in the industry–including Apple–bought Broadcom chips that included radios (i.e. broadcasting and receiving devices) for Bluetooth, WiFi and FM baked into a block on the chip. Just about anyone can download a spec sheet for the LTE modem chips that are in pretty much every phone and you will see a reference to FM radio. For example, the Qualcomm spec sheet is very clear about having FM abilities.
However, Apple no longer buys “commodity” chips–generic chips sold to everyone–and instead has chips made to their specs. They buy so many of these things that it’s able to ask for very specific things across a whole range the iPhone parts they source from suppliers. Pre-7 iPhones have the FM radio”taped off,” turned into “dark atoms.” There’s no physical connection between it and the rest of the phone that would allow for any kind of FM reception. That means you can’t just flip a switch with those phones and turn them into a usable FM receiver.
Looking at the iPhone 7 and beyond, FM radio has been left off the chip entirely in favour of things like power management and better battery life.
Still, this doesn’t mean that FM received is mobile phones isn’t a good thing. It is. We’ve just seen examples where natural disasters have hit and radio is the only form of communication. Ask those folks in the middle of the California wildfires how their Internet and cell reception is doing.
And FM radio is very important to cell phone users in other parts of the world. In countries where data is too expensive relative to income–think India and Pakistan–this is how people get their cricket scores and other news.
So while Ajit Pai might have got it slightly wrong with his understanding of FM chips in iPhones, he’s not wrong. Apple should get with the program. Free the FM chip!
UPDATE: This email has some additional detail.
Sorry dude, it’s on die, just not bonded out. When we spun the die we actually put it back in. Spent $90k to do it. The die is sold to more than 1 customer. We offer smaller packages with less pins for some customers. The earlier Apple phones just didn’t connect the antenna pin through a capacitor to the headphone jack.
We knew the ITU-R [the International Telecommunications Sector, an organization in charge of standards for radio communication frequencies] was changing the requirements to offering a public radio.
Now Apple is smart, they will find a way out of this tight spot. They now scrambling with no good options, all for one pin and a $0.002 capacitor and a headphone jack. They don’t have the room, they could use a disconnected power cord as an antenna, or add a headphone jack. I don’t know how they fix this without a redesign, a place for a bigger package and antennas or headphone or a leash antenna. It is sort of a self-inflicted marketing mess.
The EU may require a public radio in all GSM phones by 2020 or 2021. It can be AM or FM under the proposal, but AM antennae are big.
The EU is thinking phones without public radio can’t be resold after mandate.
Regulatory EU effort is still sausage, ideas still being considered
Well, that just confuses things more, doesn’t it? Another email came in today with more elaborations.
Please consider the process of how we got here, with no public broadcast radio on Apple, and is because of insecurity, and could this mess with their marketing?
Why was Apple concerned about FM radio? When can they give us this life-saving feature? Is regulatory going to happen? Can they add additional features, perhaps a public service radio scanner?
Also, I had to correct your assumptions. Sometimes, it’s more work to yank a function out of a complex circuit. You have to retest everything, and how much room did you just save? It’s on the die, uses no power, and you only loose time if you mess with it.
The circuits are on the die but nothing is connected to the AFE. Bringing the AFE to the outside world requires a new bigger package, another pin, a pcb re-design, an antenna of some kind, a non-connected wire like a headphone. So why would it matter if the circuit is on the die, it might as well be on Pluto. The registers can be written to and the phones current jumps about 61 microamps on the I7. Have not seen an I8. But it doesn’t matter, just because a silicon mask set doesn’t change, everything else product downstream to the customer does change.
Why not AM radio instead using the human as the antenna. Did you know the FM radio design has RDS and stereo? A silicon spin could implement a more advanced radio, turn the phone into an emergency police radio receiver at 135-150 Mhz narrow band FM. We could get FM stereo and a police scanner in a tiny function for emergency use. AM radio could be possible if a human was in contact with the phone.
My old Lumia 950 allowed me to listen to Sacramento’s Capital Public Radio during the Nevada County Lobo fire last week in California. I almost forgot the phone could work as a radio. We had no power, no cell phone access because the batteries died at the cell tower without utilities. At 3 AM on Monday morning I awaken to my UPSes singing. My FM radio on my phone allowed me to know at 6 AM where the fire was and that it was advancing away from my house. I felt safe to start the generator, no utility power, and make coffee at 7 AM and not run for my life. I couldn’t see more than 50 feet outside. If I didn’t have the FM radio I would have spent a week evacuated from my home with my horses at the fairgrounds. Cause in California, once you leave an evacuation area, you can’t return, but they can’t force a landowner to evacuate.
Apple was fearful that free FM radio would interfere with Apple sales. Wireless operators were concerned they couldn’t sell data. The FM radio started as an interesting way to use white space on a die we designed for Nokia. The part was pad limited when it was just 802.11b, Bluetooth and FM in 1998. Silicon guys hate white space. The public radio has always been there but it’s not used very often.
There was always been an emergency use function intended but Apple never got that.