CD3215 Bootup Sequence

Getting 20V on the charger

If a CD3215 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 CD3215 can often cause a loop at step 10. All of the CD3215s need to be fully functional and communicate with the SMC before the CD3215 connected to the charger will request 20V.

The TBT ROM is required to get to 20V. It is powered by the CD3215 on the opposite side. It will not boot unless it can communicate. It seems with liquid in that area, the trace between the LDO of the CD3215 and TBT ROM gets damaged at the test point.

Please note, the chip designations and net names are from an A1706.

Steps Before 20V on Charger

Step	Source	Name of Net	Voltage
1	J3300	PP20V_USBC_XB_VBUS	5V
2	U3200	PP3V3_UPC_XB_LDO	3.3V
		PP1V8_UPC_XB_LDOA	1.8V
		PP1V8_UPC_XB_LDOD	1.8V
		PP1V1_UPC_XB_BMC	1.1V
3	U3200	HV_GATE1	High(5v, later 20V)
	U3200	HV_GATE2	High(5v, later 20V)
4	Q3200	PPDCIN_G3H	5V
5	U7000	TBA_VDDA	5V
6	U7000	PM_EN_P3V3_G3H	3.3V (5V on many boards)
7	U6903	PP3V3_G3H	3.3V
8	U5000	PP1V2_G3H_SMC_VDDC	1.2V
9	U5165	PP3V0_G3H_AVREF_SMC	3.0V
10	U5000	SMBUS_SMC_4_G3H_SCL	3.3V (clock)
	U5000	SMBUS_SMC_4_G3H_SDA	3.3V (data)
11	U3200	USB_XB_CC1	0.8V (data) (verify)
	U3200	USB_XB_CC2	0.8V (data) (verify)
12	J3300	PP20V_USBC_XB_VBUS	20V
	J3300	PP20V_USBC_XB_VBUS	20V
13	J3300	HV_GATE1	>20V
	J3300	HV_GATE2	>20V
14	Q3200	PPDCIN_G3H	20V
15	R7015	TBA_AUX_DET	5V
16	U7000	SMC_RST_L	3.3 (verify)
17	U7000	Q7030 Q7040 opening	Unknown (low maybe)

Booting fully

Thunderbolt is required to get 20V.

If you get a message saying Critical Update Required there may be a problem with the logic board.