NXP’s 1610A3 “TRISTAR2” IC (commonly known as “U2”) handles protocol negotiation for the 8 Pin Lightning Port.
The 1610Ax is mostly responsible for detecting what is connected to the device and assigning it the appropriate functions. Technically, the 1610A3 is the 6th revision of the Tristar IC, and is therefore less failure prone than prior versions.
The 1610A3 Tristar provides 2x power outputs (PP_E75_TO_TRISTAR), for powering external accessories, as well as 2x data pairs which can be assigned to various functions.
Depending on the accessory connected, available functions can be up to 2 of any of the following:
- MIKEYBUS (Digital Audio Codec Output, eg. iPhone 7> Headphones).
- ACCESSORY UART (UART/Serial Interface for HIDs ect).
- SOC USB (USB Communication with CPU when connected to computer, else identifies charger type to determine available current).
- BB DEBUG USB** (Baseband Debugging USB interface).
- DEBUG UART** (UART/Serial Debugging for the SOC/CPU).
- WRT SOC** (UART Interface for Baseband CPU Programming/Debugging).
**Primarily used by manufacturer. (Apple, Foxconn)
Symptoms of Failure
Due to the complexity of the Tristar IC, and the many connections it has, symptoms of failure can vary in each case. Here are some of the most notable ones:
- Rapid Discharge of Battery.
- No Charging, or no current draw.
- No USB connection to computer.
- “Accessory Unsupported” messages in iOS.
- Blue Screen of Death (BSOD).
- Red Screen of Death (RSOD).
- Kernel Panic/Bootloop.
- No Digital Audio Output.
- Failure to work with certain accessories.
- Error 9, 4005, 4013, 4014 during Update/Restore.
- Sudden Death (Device has no signs of life at all).
The 1610A3 is backwards compatible with the 1610A2, and 1610A1, and can be used in the following devices:
- iPad Mini 2 (U1300)
- iPad Mini 3 (U1300)
- iPad Mini 4 (U1300)
- iPad Air (U6000)
- iPad Air 2 (U3500)
- iPhone 5C (U2)
iPhone 5C (U2)
- iPhone 5S (U2)
iPhone 5S (U2)
- iPhone 6 (U1700)
iPhone 6 (U1700)
- iPhone 6 Plus (U1700)
iPhone 6 Plus (U1700)
- iPhone 6S (U4500)
iPhone 6S (U4500)
- iPhone 6S Plus (U4500)
iPhone 6S Plus (U4500)
- iPhone SE (U4500)
iPhone SE (U4500)
Here’s a video of our experienced technician replacing a 1610A1 Tristar, with a 1610A3 in an iPad Air 2. He performs what is known as a “clean pull”, where the Balls under the IC are split evenly.
This enables him to place a new Tristar, without first preparing the pads with a soldering iron. Doing so allows the pads to keep their original structural integrity, consequently resulting in a more robust repair for the customer.