Hi Team,
Does BUF16821 have the spec of re-power on time? or any spec that acceptable initial voltage.
I mean if I plug on/off the power supply quickly, does IC fail start up?
Regards,
Roy
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Hi Roy,
I have notified our expert regarding this topic. Please expect a response by 5/25/20.
Thanks,
Costin
Hi Costin,
Thank you for your help. Could you help notice the expert today again. Customer schedule is urgent.
Regards,
Roy
Hi Roy,
BUF1681 will not "failed" the power on/off, the output response will follow the control power on sequence.
BUF16821 has two internal power-up threshold:
1) 2V threshold, up tp this threshold the output voltage is same as Vs, above 2V output voltage is Vs/2
2) 5V threshold- at Vs=5V, the device automatically updates the non-volatile stored values into the DAC output. After Vs reaches 5V for ~1mS
output will be be Vs/2 until the automatic read finish this update. This timing is a critical in the system if Vs ramp is fast and output non-volatile store value is different from Vs/2.
For example: Vout set Vs/3, Vs=12V and Vs ramp up time = 1mS.( datasheet fig23 with a faster Vs)
a) up to 2V Vout=Vs
b) 2V<Vs<5V, output = Vs/3
c) Vs>5V, output = Vs/2 for 1mS. Since Vs ramp is 1mS, output will get to 6V before switching to the programed output voltage =4V. This may look like a device malfunction due to fast Vs ramp up.
Another potential issue during Vs On/Off is the risk to damage the internal ESD diode. If the output capacitance is large,for short time Vout > Vs+diode vollage..In this condition the internal ESD protection diode will turn on, a series resistor at the output is needed to protect The ESD diode.
Regards,
Costin