I have some Adafruit neopixels that only run on 5v and will not run on 3.3v. In the ring I tested, it will work with 5v power, and 3.3v signals. I also have neopixels that will not function correctly if given 5v power and 3.3v signals. I have read about other ws2812/ws2812b’s that needed both 5v power and signals. So, I want to make sure the new design will work with any ws2812 led, hence doing level shifting to 5v.
This article looked at several level shifters on the market at the time, and found most of them did not work all of the time, but the TXS-0102 did for small number of ws2812’s and the 74HCT245 did the job perfectly. http://happyinmotion.com/?p=1247
However, I’m running out of room in the perfboards/breadboards I’m using, and I’m looking for something smaller than a pair of TXS-0102’s (I also need 5v i2c for a lcd screen). So, I ordered your unit, in hopes that it would work with an extra pull-up resistor on each side. My other thought is to mount a pair of TXS-0102’s vertically, sharing the OE/power/ground pins if I can’t get your unit to work.
If I still have problems, I have an backup plan to not use the Teensy for neopixel projects, and stick with 5v processors. To that end, I bought 2 pololu A-star LV’s during the recent sale that just expired, and they just arrived (I expect the level shifters on Monday). Given it has a built-in step-up/step-down voltage converter that can go up to 1a, it looks like it will run my ws2812’s fine. However, there are some things that the ATmega32u4 doesn’t have that the Teensy has (multiple uarts, touch reading, DAC), so I would prefer to stick with the Teensy.
In terms of needing more power due to using the higher resistors, I’m not going to worry about that. I suspect it won’t be noticeable when I’m running ws2812 leds, since they will draw much more power.
In terms of PWM, I was just wondering if the normal analogWrite (PWM) worked through the level converters. Off hand, I don't recall what the frequencies are for PWM on Teensy.