A Quick Look At USB Power Delivery Support of the Apple 87W USB-C Power Adapter

The Apple 87W USB-C Power Adapter ships with the Apple 15" MacBook Pro (2018) to provide USB Power Delivery 2.0 rapid charging to the Mac. Click here to see how well the 87W adapter delivers USB Power Delivery fast charging to the Mac through the Thunderbolt 3 port while connected using the supplied Apple USB-C Charge Cable (2m).

We can view more details on how the Apple 87W USB-C Power Adapter supports power using the USB Power Test App from Granite River Labs with the Granite River Labs USB Power Delivery Compliance C2 Tester to produce the following test results.

The USB Power Test App first negotiates a power contract for every PDO supported by the 87W adapter, and increases the load gradually to find the threshold where over current protection (OCP) kicks in and voltage and current start to drop for safety reasons.  

The USB Power Test App reports out all the PDO's supported by the 87W adapter and their OCP thresholds. OCP thresholds for the 87W adapter are set at about 6-54% above the maximum current levels for the fixed PDO's.

PDO	OCP (A)
PDO#1 Fixed: 5V 2.4A	3.39
PDO#2 Fixed: 9V 3A	3.47
PDO#3 Fixed: 20V 4.35A	4.63

The USB Power Test App from Granite River Labs also produces an I-V curve which graphically shows the relationship between voltage and current for each PDO. We can see the voltage immediately shuts off once the current increases beyond the OCP threshold.

The USB Power Test App can also use the Granite River Labs USB Power Delivery Compliance C2 Tester integrated with the GW Instek APS-7100 programmable AC power supply to compare the charger's power output vs power input so that power efficiency can be measured and compared to regulatory limits from United States of Energy (DOE) Level VI or European Union's CoC Tier 2 requirements. We can repeat the power efficiency tests for different PDO's, current load conditions, and different AC input ranges, allowing us to get a complete picture of power efficiency ranges across all different usage scenarios.

Using the USB Power Test App and FLIR thermal imaging tools, we measured the heat emitted by the Apple 87W USB-C Power Adapter as seen in the following temperature readings and traces for the highest 20V, 4.35A PDO, where we observed a max temperature of 66.35 degree Celsius. Note the 87W charger runs cooler than the Insignia 90W Type-C Wall Adapter (click here for review).

Using the USB Power Delivery Compliance C2 Tester from Granite River Labs to run just a subset of the full USB Power Delivery compliance test suite, some compliance failures were observed for the Apple 87W USB-C Power Adapter.

USB-IF High Level Mapping Summary

Sl No	Test Category	Test Group Description	Test Result
1	PHY_PRIMARY_TX	BMC Physical Layer Transmitter	PASS
2	PHY_PRIMARY_RX	BMC Physical Layer Receiver	PASS
3	PHY_PRIMARY_MISC	BMC Physical Layer Miscellaneous	PASS
4	PROT_PRIMARY	Protocol Specific Primary	FAIL
5	POWER_PRIMARY	Power Source/Sink Primary	FAIL

Result Summary

Sl No	Test ID	Test Name	Test Result
1	TDA.2.1.1.1	TDA.2.1.1.1 BMC PHY TX EYE	PASS
2	TDA.2.1.1.2	TDA.2.1.1.2 BMC PHY TX BIT	PASS
3	TDA.2.1.2.2	TDA.2.1.2.2 BMC PHY RX INT REJ	PASS
4	TDA.2.1.2.1	TDA.2.1.2.1 BMC PHY RX BUSIDL	PASS
5	TDA.2.1.3.1	TDA.2.1.3.1 BMC PHY TERM	PASS
7	TDA.2.2.1	TDA.2.2.1 BMC PROT SEQ GETCAPS	PASS
8	TDA.2.2.2.1	TDA.2.2.2.1 BMC PROT SEQ CHKCAP P PC	PASS
9	TDA.2.2.2.2	TDA.2.2.2.2 BMC PROT SEQ CHKCAP NOMARK P PC	PASS
13	TDA.2.2.7	TDA.2.2.7 BMC PROT BIST NOT 5V SRC	PASS
15	TDA.2.2.9	TDA.2.2.9 BMC PROT GSC REC	FAIL
16	TDA.2.3.1.1	TDA.2.3.1.1 POW SRC LOAD P PC	FAIL
17	TDA.2.3.2.1	TDA.2.3.2.1 POW SRC TRANS P PC	PASS

BMC Eye Diagram