Novena PVT2 ECO List

This is a list of all the changes applied to the board from PVT1 to PVT2 (Crowd Supply initial campaign) release. If it's not on this list, it didn't happen.

Each change has the format of issue summary/resolution, and specific change

ECO1: Improve HPD margin

HPD on i.MX6 has a low impedance (10k). This causes marginal HPD performance on some boards. Make R29L stronger.

PVT1	PVT2	Notes
R29L 10k, 1% / REC1005N	R29L 1k, 1%	HDMI HPD perforance

ECO2: EOL issue U11D

STMPE610 is EOL. Switch to STMPE811, pin-compatible and not EOL.

PVT1	PVT2	Notes
U11D STMPE610	U11D STMPE811QTR	resolve EOL issue

ECO3: EOL issue audio amplifier

NS4890 is EOL. Replace with compatible NS4890B in two places.

PVT1	PVT2	Notes
U10A, U12A NS4890	U10A, U12A NS4890B	resolve EOL issue

ECO4: Improve kernel panic logging

U10S is too small for good kernel panic logging. Replace with larger capacity I2C EEPROM to store several crashes worth of logs.

PVT1	PVT2	Notes
U10S 24LC32A-I/ST	U10S FT24C512AUTR-T	improve KP logging

ECO5: 47uF 1206 capacitor is wrong AGAIN

The wrong package type (1210) is being ordered for this 1206 part. This was supposed to be corrected on PVT1. Please double-confirm that instruction is understood that this part cannot be substituted with a 1210 footprint.

DVT and PVT1	PVT2	Notes
C43M 47uF, 6.3V, 20% X5R	47uF, 6.3V, 20% X5R (CL31A476MQHNNNE)	double-confirm this change is understood!
C44M 47uF, 6.3V, 20% X5R	47uF, 6.3V, 20% X5R (CL31A476MQHNNNE)
C45M 47uF, 6.3V, 20% X5R	47uF, 6.3V, 20% X5R (CL31A476MQHNNNE)
C18M 47uF, 6.3V, 20% X5R	47uF, 6.3V, 20% X5R (CL31A476MQHNNNE)
C52C 47uF, 6.3V, 20% X5R	47uF, 6.3V, 20% X5R (CL31A476MQHNNNE)

ECO6: Upgrade accelerometer

Old accelerometer is probably approaching EOL.

MMA8452Q is stocked at 3mm+ levels in the factory and has existing Linux drivers in main-line. A little more expensive than MMA8653FC, but twenty cents is not going to kill this product. So, we go with MMA8452Q.

PVT1	PVT2	Notes
U10D MMA7455L	U10D MMA8452Q	improve accelerometer, avoid EOL
R17D 20k, 1%	removed	INT output is now push/pull

ECO7: Upgrade FAN53540UCX

FAN53540UCX marked as not recommended for new designs.

FAN53541UCX is a pin-compatible upgrade. Difference between the two is that the enable and mode input no longer need 1k ballast resistors. However, leaving them in place causes no harm and allows for downgrade compatibility in case parts are in short supply.

PVT1	PVT2	Notes
U13N FAN533540UCX	U13N FAN53541UCX

ECO8: Update i.MX6 P/N

Previously schematic listed the 1.0GHz P/N as the default. Updated to reflect the plan to only produce with the 1.2GHz P/N.

PVT1	PVT2	Notes
U100 iMX6Q - PCIMX6Q5EVT10AD	U100 iMX6Q - MCIMX6Q5EYM12AC

ECO9: Confirm change of D10C

Measurements on diode leakage indicate D10C was not properly updated on BOM at last ECO. Confirm factory received ECO update.

DVT/PVT1	PVT2	Notes
D10C NSR0320	D10C RB751V40,115	Reduce leakage from 1mA max to 0.0005mA max; peak If = 120mA, but max current on stby line is ~1mA

ECO10: U12N is EOL

U12N, the lower synchronous switch of the 5V converter, has gone EOL. Replace with recommended substitute by On Semi.

The recommended substitute NTMFS4C35NT1G is pin-compatible. It has a slightly lower power rating due to a higher Tj to the case, but the RdsON is the same. The converter is actually highly over-spec'd for the measured loads, so this substitution is not a problem. In fact, the substitute may improve efficiency slightly as the gate charge and other parasitics of the new device are lower.

PVT1	PVT2	Notes
U12N NTMFS4935NT1G	U12N NTMFS4C35NT1G

ECO11: Remove AW-NU137 option

AW-NU137 is EOL and also, we're just never going to use it. It was originally included as an option for wifi in devices that needed to be cheap and where it was acceptable to not have PCIe and also binary blobs are acceptable. There has been zero demand for this configuration option.

PVT1	PVT2	Notes
P12U 2mm 5-pin male header	remove
C30U 0.1uF, 25V, X5R	remove
C29U 10uF, 10V, X5R, 20%	remove
D13U RSA5M	remove
U12U RT9706	remove
C26U 1.0uF, 25V, 20% X5R	remove
R23U 10k, 1%	remove
R26U 0 ohm	remove	replace with permanent traces
R27U 0 ohm	remove	replace with permanent traces

ECO12: Fix CDP issue on USB port EXT2

USB port EXT2 has 1.5A-capable limits but does not configure itself as CDP. Fix this by swapping Port4 (EXT2 on PVT1) for Port 1 (USB_VID on PVT1). Amber1/Green4 NC (as currently configured) sets only Downstream Port 1 as CDP-capable.

This is purely a wire fix, no BOM-visible ECO required.

ECO13: Improve inductor profile

The ferrite MSS1260 used as the primary power inductor is a bit too tall and large. Use a composite molded core XAL7030 which is a bit more compact.

Pros/cons: XAL7030 has a better rated Irms than MSS1260, but seems mostly due to better heat conduction out of the package, not due to better electrical performance. The DCR of XAL7030 is 19.5mOhm, MSS1260 is 12.60mOhm, so conduction losses are greater. Isat of the XAL7030 is better due to soft-saturating characteristic of the composite core. Overall, I expect there to be very little change in practical circuit performance, perhaps a 1-2% max loss in battery life with this change under Ipeak conditions.

The MSS1260 isn't removed from the PCB layout. Instead, XAL7030 shall be fitted inside the footprint of the MSS1260. This allows for going back to the original inductor in case there is a design issue with the XAL7030.

This change is coordinated onto Senoko BOM as well.

PVT1	PVT2	Notes
L10N 3.3uH, MSS1260-332NL	L10N 3.3uH, MSS1260-332NL (DNP)	remove from BOM but leave footprint
add	L10NB 3.3uH, XAL7030-332MEC	add inductor within old footprint