I am using a 100nF ceramic and 10uF tantalum for bypassing ADC , DAC and VRef.
Is that enough?
Do you mean you have one 100nF ceramic and one 10uF tantalum for all 3 or that they have a pair each?
A pair of 100n and 10uF for 3 of those.
No, you want at least one 100nF per chip as close to the pins as possible, if the chips are all close you may get away with a single 10µF capacitor.
Is adding a TVS diode to the input and output a good idea?
Input of what?
input of psu
If you are powering it off a mains transformer it should not be neccessary. No harm in using one if you want to. Be sure to understand all the specs of the TVS, they don't trigger on/off at a single threshold.
I am using a AC to DC adapter 19 V 2 A
I am using a 100nF ceramic and 10uF tantalum for bypassing ADC , DAC and VRef.
Is that enough?
Do you mean you have one 100nF ceramic and one 10uF tantalum for all 3 or that they have a pair each?
A pair of 100n and 10uF for 3 of those.
No, you want at least one 100nF per chip as close to the pins as possible, if the chips are all close you may get away with a single 10µF capacitor.
Yes, I am using 100nF for every chips.
Here is the
TVS diode I am going to use. I have read the full datasheet.
It has a breakdown voltage of 22.2 to 24.5V. Max. reverse leakage current of 1µA. Max. clamping voltage of 32.4V. And maximum peak pulse surge current of 12.3A.
That will be good enough for my purpose.
Here is the TVS diode I am going to use. I have read the full datasheet.
It has a breakdown voltage of 22.2 to 24.5V. Max. reverse leakage current of 1µA. Max. clamping voltage of 32.4V. And maximum peak pulse surge current of 12.3A.
That will be good enough for my purpose.
No it won't, check the reverse standoff voltage. it will turn on at 22.2-24.5V but will not turn off again until 2-3 volts lower, if this is near the peak voltage of the supply you can get it triggered permanently.
Here is the TVS diode I am going to use. I have read the full datasheet.
It has a breakdown voltage of 22.2 to 24.5V. Max. reverse leakage current of 1µA. Max. clamping voltage of 32.4V. And maximum peak pulse surge current of 12.3A.
That will be good enough for my purpose.
No it won't, check the reverse standoff voltage. it will turn on at 22.2-24.5V but will not turn off again until 2-3 volts lower, if this is near the peak voltage of the supply you can get it triggered permanently.
its 20V(standoff voltage)
there is no tvs diode with low standoff voltage with min breakdown voltage more than 20V in RS components. I might abandone the idea of tvs diode.
Really? usually the reverse standoff in a few volts less than the breakdown voltage.
Really? usually the reverse standoff in a few volts less than the breakdown voltage.
I mean that the value in the datasheet says 20V.
where? remember hat one datasheet will over many parts
wait i forgot the part number
I think it will turn off at 20.5V
Is that ok?
I will choose one with higher standoff voltage.
I chose
this one.
It has a maximum reverse standoff voltage of 24V. Minimum breakdown voltage of 26.5V and maximum clamping voltage of 70V.
This will be okay.
I chose this one.
It has a maximum reverse standoff voltage of 24V. Minimum breakdown voltage of 26.5V and maximum clamping voltage of 70V.
This will be okay.
Its differential resistance is too high
Ok, final decision.
I am going to use this TVS diode sm15t30ca
https://in.rsdelivers.com/product/stmicroelectronics/sm15t30ca/stmicroelectronics-sm15t30ca-bi-directional-tvs/4861253 Diode Configuration
Single
Maximum Operating Temperature
+150 °C
Number of Elements per Chip
1
Length
7.15mm
Maximum Clamping Voltage
53.5V
Minimum Breakdown Voltage
28.5V
Brand
STMicroelectronics
Maximum Peak Pulse Current
187A
Package Type
SMC
Mounting Type
Surface Mount
Minimum Operating Temperature
-55 °C
Width
6.25mm
Test Current
1mA
Maximum Reverse Stand-off Voltage
25.6V
Maximum Reverse Leakage Current
1µA
Height
2.45mm
Pin Count
2
Dimensions
7.15 x 6.25 x 2.45mm
Direction Type
Bi-Directional
Peak Pulse Power Dissipation
1500W
Can I use 6.3V tantalum capacitor to bypass 5V supply?
Just google tantalum capacitors, there will be lots of information. I don't know as i don't use them.
This is what it says on "Voltage Derating Rules for Solid Tantalum and Niobium Capacitors" by AVX.
You can probably run closer to maximum with a stable voltage, if you are smoothing a fluctuating voltage you may want more headroom for surges/spikes.
Hi, the LDO i am using (LT3080) needs a minimum output curent of 1mA.I was going to use lm334z as a constant current source.But it is only available in higher quantities.
Can i use a electronic potentiometer as a constant current source?
Or is there any simple circuits i can use as constant current source?