As the same causes tend to have the same effects, following the announcement of the Yocto-IO-V2 a few months ago, this week we present the Yocto-Maxi-IO-V3. Its internal design is a little different from the previous version, but from a functional point of view, it's exactly the same product as the Yocto-Maxi-IO-V2.
The new Yocto-Maxi-IO-V3
The Yocto-Maxi-IO-V2 is based on a rather unusual chip: ON SemiConductor's NCV7608, which was normally intended for use as a half-bridge controller. But by exploiting a technical peculiarity of this chip, it could be used as a 4-channel I/O controller. Unfortunately, in 2021, ON SemiConductor announced that it was discontinuing production of the NCV7608. We obviously reacted by buying a large stock of NCV7608s. This stock has kept us going until now, and given us enough time to find a more or less equivalent component in the form of Texas Instruments' DRV8908-Q1.
Versions 2 and 3 are equivalent
As usual, we've fought hard to ensure that version 3 is at least equivalent to version 2:
- Eight input/output channels independently configurable as input or output, open drain or not
- Channels voltage can be configured as 3V, 5V or 5 to 28V via an external power supply
- All eight channels are electrically isolated from the USB part, but share a common ground
- Same physical size, same connector location.
Version V2 and V3 side by side, differences are subtle
Somewhat more powerful...
The Yocto-Maxi-IO-V2 was limited to 250mA output power, whereas version V3 theoretically allows up to one amp per channel, provided you take care to avoid overheating and use an external power supply: don't expect to get such power from a simple USB port. The Yocto-Maxi-IO-V3, for example, can drive small stepper motors, which is more than respectable for a module normally intended to manage electrical signals.
The Yocto-Maxi-IO-V3 lets you drive small motors
...but more expensive
The bad news is that version 3 is a little more expensive than version 2, for two reasons:
- The new DRV8908-Q1 chip and the additional electronics needed to control it cost a little more than the old version,
- The unit price of a Yoctopuce module is calculated at the design stage as three times the cost of the components used to build it. This selling price is usually not changed thereafter, except in exceptional cases. The price in Swiss Francs (CHF) of the Yocto-Maxi-IO-V2 has in fact not moved since its introduction in 2017. As the Yocto-Maxi-IO-V3 price is based on the current price of the components that make it up, there is a catch-up effect.
Why aYocto-Maxi-IO-V3 but a Yocto-IO-V2?
You may be wondering why the Yocto-IO based on the DRV8908-Q1 is called V2, while the Maxi version, based on the same chip, is called V3. This little inconsistency stems from the fact that the V1 version of the Maxi-IO, which was based on discrete components, had no 4-channel equivalent.
Conclusion
We successfully managed the disappearance of the NCV7608 by migrating to the DRV8908-Q1 without any dramatic consequences for our customers. This did not seem to be a foregone conclusion when ON SemiConductor announced the disappearance of its chip without proposing a replacement. So we're pretty happy, because the Yocto-IO and the Yocto-Maxi-IO are pretty popular products.
Both versions are available in our online shop. At first sight, we still have enough Yocto-Maxi-IO-V2 left for a few more weeks, after which it will no longer be possible to order it and you will have to use the Yocto-Maxi-IO-V3, but once again, from a hardware and software point of view, the change should be totally transparent for you.
