ADAU1701 reset pin
Thread Summary
The user asked if the reset pin of the ADAU1701 can be directly connected to 3.3V for a self-boot device. The final answer indicates that a delay circuit is necessary to ensure the voltage supplies settle before the chip starts. An RC circuit with hysteresis is suggested, but the user experienced a chip failure. The user is advised to send the schematic for further debugging.AI Generated Content
I am building a self boot device using the ADAU1701 and would like to know if I need to use a delay circuit to pull the the reset pin high or can it just be connected direct to 3.3Vsupply
Audio Signal Processors
processors and dsp
SigmaDSP Audio Processors
Processors and Microcontrollers
adau1701
No, you cannot connect reset to 3.3V. The purpose is to allow for the voltage supplies to settle (and be valid) before the chip starts. The specs don't say if the input is a schmitt trigger type, to allow a RC.
If you have a uC on board, I would use it to drive reset. The reference design shows a reset generator. You could use a buffer for an RC maybe. If this is a high volume design, probably a reset generator would be best.
Thanks for the quick reply
The circuit i was looking to use is.
Do you think this is ok. I have used this with over micro controllers
Yes, I think that circuit should work. For me, rather than all those components, I would use two inverters.
But, it's possible a direct RC (and diode) might be ok. Maybe the moderator can chime in on that.
I will look at the using two inverters
The reset input does have some hysteresis, so an RC circuit should be fine. If you use this you will need to be careful that the voltage on the reset pin does not rise above Vil (0.8 V) before the IC has been properly powered-up. This will ensure that the IC boots with the reset pin held low, holding the IC in reset until the voltage rises from below Vil to above Vih.
I built the self boot circuit including the reset circuit above. I checked that all the pins had the currect voltage on them before I pulled the reset high (3.3V)
and the chip pulled alot of current and burnt out.
The chip clock was ok with reset open circuit
Pins 18,34,36,48 (3.3V)
Pins 13,24 (1.8V)
Please help
Could you either post the schematic of your design here or send it to sigmadsp@analog.com? It'll be easier for us to debug what's going on if we can look at the entire system.
This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.
Thank you,
EZ Admin
Please log in to reply.