CD3217 and T2 Power on Sequence

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If a CD3217 does not have the LDO outputs, test the lines for shorts, otherwise the chip is missing power or bad. Data sheet of closest Ti chip.

A bad CD3217 can often cause a loop at step 10. All of the CD3217s need to be fully functional and communicate with the SMC before the CD3217 connected to the charger will request 20V

These documents are for specific boards, but will likely apply to most T2 Mac. Any net names and designators will be specific to the board it is from.







T2 Power rails resistances (820-01700)


PP0V82_SLPDDR 30-40 Ohm


PP1V1_SLPS2R 1-2 kOhm


PP1V8_SLPS2R 4 kOhm

820-001700 CD3217 Compatibility issues

CD3217s from 2020/M1 boards will not work.

Symptoms of compatibility issue: PPBUS ~12.30, all ports are switching to 19V with T2 boot/or one side will turn 19v, another stays on 5v (19v 0.05-0.1A) there will be a visible heat spot on T2 1st pin corner (inner side since T2 itself is approx 2 smaller than IC)

Device will start from charged battery, there will be no issue with usb devices but charger wont be recognized.

To solve you need full set of compatible CD3217, just pair wont help as well as tbt rom swap, DFU Recovery, etc.

Generally 001700 behaviour is very inconsistent. some boards might start with only one cd3217 present on board (should be the one connected to tbt rom of course), some will stuck in 5V 0.2A, some will stuck in 19v 0.1A(basically same power consumption).

Probably there are multiple revisions of the board, images pending. If you can add some more info, please report your revision / cd3217 behaviour below.

T2 PMIC 001700 revision 1(black dot inductors)

Revision 2 (white dots)

820-001700 CD3217 revisions list

Case 1: MacBook Pro 16" 2019 With CD3217 rev. 9AP0NVQ No power with one side of newer 12P1FXQ(took from 2020 board), Symptoms: quick T2 boot, 19V mode + hot T2 Corner on original side, 5v 0.2A on another. PPBUS 12.3V


CD3217 B12 09P09CQ

Possibly alternative revision with TI logo on chip, CD3217 B12 02P04ES


CD3217 B12 97P146Q

Small T2 top side diode measurements

There are more power lines than 1v1slps2r, they just somewhat got lost in the process of uploading. Maybe I'll fix that later. Those are in case you wonder if you have a broken line between T2 and it's RAM, or have some pins torn.


T2 types

А2159 А2289 Big T2 Package (PMU is also different!)

А1932, А2179, А1989, А1990, А2141 small T2 Package

There are also 2 types of DDR used on T2 chips: 1GB and 2GB. This is critical if you upgrade SSD from <TB to > 1TB. 1TB and above requires 2GB DDR since it is used as SSD cache.

Known types of RAM + APL number: APL1027 with h9hknnn8kumuvr Hynix Chip.

There is also BOM table in schematics, but it listed apple part number(339Sxxxxx) does not seem to correlate (based on 5 boards). However, it lists 2 different Ram manufacturers, Hynix and Micron.