Aluminum electrolytic or ceramic capacitors for linear regulator input and output?












1












$begingroup$


I am using this linear voltage regulator. The datasheet indicates the input and output values for the capacitance to use, 1uF and 10uF respectively.



Should these capacitors be or a particular type, or does it not matter?










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$endgroup$












  • $begingroup$
    This answer is related: electronics.stackexchange.com/a/426181/202270
    $endgroup$
    – Edgar Brown
    1 hour ago






  • 2




    $begingroup$
    I agree with the general consensus. Another option is to use ceramic caps but put a resistor in series to insure stability. Another option is to contact ST micro and just ask them.
    $endgroup$
    – mkeith
    26 mins ago
















1












$begingroup$


I am using this linear voltage regulator. The datasheet indicates the input and output values for the capacitance to use, 1uF and 10uF respectively.



Should these capacitors be or a particular type, or does it not matter?










share|improve this question









$endgroup$












  • $begingroup$
    This answer is related: electronics.stackexchange.com/a/426181/202270
    $endgroup$
    – Edgar Brown
    1 hour ago






  • 2




    $begingroup$
    I agree with the general consensus. Another option is to use ceramic caps but put a resistor in series to insure stability. Another option is to contact ST micro and just ask them.
    $endgroup$
    – mkeith
    26 mins ago














1












1








1





$begingroup$


I am using this linear voltage regulator. The datasheet indicates the input and output values for the capacitance to use, 1uF and 10uF respectively.



Should these capacitors be or a particular type, or does it not matter?










share|improve this question









$endgroup$




I am using this linear voltage regulator. The datasheet indicates the input and output values for the capacitance to use, 1uF and 10uF respectively.



Should these capacitors be or a particular type, or does it not matter?







capacitor linear-regulator






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked 2 hours ago









A.S.A.S.

436214




436214












  • $begingroup$
    This answer is related: electronics.stackexchange.com/a/426181/202270
    $endgroup$
    – Edgar Brown
    1 hour ago






  • 2




    $begingroup$
    I agree with the general consensus. Another option is to use ceramic caps but put a resistor in series to insure stability. Another option is to contact ST micro and just ask them.
    $endgroup$
    – mkeith
    26 mins ago


















  • $begingroup$
    This answer is related: electronics.stackexchange.com/a/426181/202270
    $endgroup$
    – Edgar Brown
    1 hour ago






  • 2




    $begingroup$
    I agree with the general consensus. Another option is to use ceramic caps but put a resistor in series to insure stability. Another option is to contact ST micro and just ask them.
    $endgroup$
    – mkeith
    26 mins ago
















$begingroup$
This answer is related: electronics.stackexchange.com/a/426181/202270
$endgroup$
– Edgar Brown
1 hour ago




$begingroup$
This answer is related: electronics.stackexchange.com/a/426181/202270
$endgroup$
– Edgar Brown
1 hour ago




2




2




$begingroup$
I agree with the general consensus. Another option is to use ceramic caps but put a resistor in series to insure stability. Another option is to contact ST micro and just ask them.
$endgroup$
– mkeith
26 mins ago




$begingroup$
I agree with the general consensus. Another option is to use ceramic caps but put a resistor in series to insure stability. Another option is to contact ST micro and just ask them.
$endgroup$
– mkeith
26 mins ago










2 Answers
2






active

oldest

votes


















3












$begingroup$

It doesn't usually matter, but be aware that some linear regulators--the popular LM2940 series, for example--may be unstable if the output capacitor's ESR is too high or too low. As the datasheet for your regulator doesn't seem to say anything about that at a glance, it should be fine with any capacitors you pick, but see the edit below for a warning.



Non-polarized capacitors more than about a microfarad used to be rare and expensive, which is probably why the datasheet shows polarized capacitors being used. Today, you can get 10μF ceramic capacitors for less than $0.30 each.





Edit: As @ThePhoton points out, this regulator may be so old that multi-microfarad ceramic capacitors, with their inherent low ESR, may have been a far-off pipe dream to the engineers writing the datasheet. So this may still be unstable with too low an ESR on its output, so unless you want to test its stability under different operating conditions with the ceramic caps, it may be best to stick to aluminum electrolytics. After all, that's probably what the IC's designers had in mind.






share|improve this answer











$endgroup$









  • 3




    $begingroup$
    The chip might just be so old that when they wrote the datasheet, they didn't consider the possibility that someone would want to use a low-ESR ceramic capacitor for such high values (1 and 10 uF). I'd stick with electrolytic unless I had time to experiment and make sure it stays stable with ceramic over all operating conditions (temperature, input voltage, etc).
    $endgroup$
    – The Photon
    1 hour ago






  • 1




    $begingroup$
    That's a good point, @ThePhoton. Then again, MLCCs are relatively high ESR as ceramics go, and you can get pretty low ESR electrolytics--I'm not sure how they compare, but you do make a good point and I'll add a note to that effect in the answer.
    $endgroup$
    – Hearth
    1 hour ago



















0












$begingroup$

The datasheet application circuit example schematic shows a 1 microfarad polarized capacitor on the input and a 10 microfarad polarized capacitor on the output. Since the values are in the 1 plus microfarad range and the capacitors are shown as polarized, I would guess that the manufacturer (ST) wants you to use electrolytic caps. I guess you could use a tantalum caps, but unless the datasheet specifies tantalum, that would be a needless expense.



The polarized caps shown on the datasheet circuit lead me to believe that electrolytic caps are what are intended. Very few ceramic caps are over 1 microfarad and very few are polarized.






share|improve this answer









$endgroup$









  • 1




    $begingroup$
    Actually, ceramic capacitors of up to hundreds of μF are, while not common, certainly readily available. They're not terribly expensive, either. Ceramic capacitor technology has improved dramatically in the past decade or so.
    $endgroup$
    – Hearth
    1 hour ago






  • 2




    $begingroup$
    I agree with Hearth that you're wrong to say 1 uF and up are rare as ceramics. But I'd still advise OP to stick with electrolytics since older regulator designs depend on a reasonably high ESR in the capacitor to maintain stability. If the datasheet doesn't promise the regulator is stable with low-ESR or ceramic output capacitors, it's not wise to assume it will be.
    $endgroup$
    – The Photon
    1 hour ago











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









3












$begingroup$

It doesn't usually matter, but be aware that some linear regulators--the popular LM2940 series, for example--may be unstable if the output capacitor's ESR is too high or too low. As the datasheet for your regulator doesn't seem to say anything about that at a glance, it should be fine with any capacitors you pick, but see the edit below for a warning.



Non-polarized capacitors more than about a microfarad used to be rare and expensive, which is probably why the datasheet shows polarized capacitors being used. Today, you can get 10μF ceramic capacitors for less than $0.30 each.





Edit: As @ThePhoton points out, this regulator may be so old that multi-microfarad ceramic capacitors, with their inherent low ESR, may have been a far-off pipe dream to the engineers writing the datasheet. So this may still be unstable with too low an ESR on its output, so unless you want to test its stability under different operating conditions with the ceramic caps, it may be best to stick to aluminum electrolytics. After all, that's probably what the IC's designers had in mind.






share|improve this answer











$endgroup$









  • 3




    $begingroup$
    The chip might just be so old that when they wrote the datasheet, they didn't consider the possibility that someone would want to use a low-ESR ceramic capacitor for such high values (1 and 10 uF). I'd stick with electrolytic unless I had time to experiment and make sure it stays stable with ceramic over all operating conditions (temperature, input voltage, etc).
    $endgroup$
    – The Photon
    1 hour ago






  • 1




    $begingroup$
    That's a good point, @ThePhoton. Then again, MLCCs are relatively high ESR as ceramics go, and you can get pretty low ESR electrolytics--I'm not sure how they compare, but you do make a good point and I'll add a note to that effect in the answer.
    $endgroup$
    – Hearth
    1 hour ago
















3












$begingroup$

It doesn't usually matter, but be aware that some linear regulators--the popular LM2940 series, for example--may be unstable if the output capacitor's ESR is too high or too low. As the datasheet for your regulator doesn't seem to say anything about that at a glance, it should be fine with any capacitors you pick, but see the edit below for a warning.



Non-polarized capacitors more than about a microfarad used to be rare and expensive, which is probably why the datasheet shows polarized capacitors being used. Today, you can get 10μF ceramic capacitors for less than $0.30 each.





Edit: As @ThePhoton points out, this regulator may be so old that multi-microfarad ceramic capacitors, with their inherent low ESR, may have been a far-off pipe dream to the engineers writing the datasheet. So this may still be unstable with too low an ESR on its output, so unless you want to test its stability under different operating conditions with the ceramic caps, it may be best to stick to aluminum electrolytics. After all, that's probably what the IC's designers had in mind.






share|improve this answer











$endgroup$









  • 3




    $begingroup$
    The chip might just be so old that when they wrote the datasheet, they didn't consider the possibility that someone would want to use a low-ESR ceramic capacitor for such high values (1 and 10 uF). I'd stick with electrolytic unless I had time to experiment and make sure it stays stable with ceramic over all operating conditions (temperature, input voltage, etc).
    $endgroup$
    – The Photon
    1 hour ago






  • 1




    $begingroup$
    That's a good point, @ThePhoton. Then again, MLCCs are relatively high ESR as ceramics go, and you can get pretty low ESR electrolytics--I'm not sure how they compare, but you do make a good point and I'll add a note to that effect in the answer.
    $endgroup$
    – Hearth
    1 hour ago














3












3








3





$begingroup$

It doesn't usually matter, but be aware that some linear regulators--the popular LM2940 series, for example--may be unstable if the output capacitor's ESR is too high or too low. As the datasheet for your regulator doesn't seem to say anything about that at a glance, it should be fine with any capacitors you pick, but see the edit below for a warning.



Non-polarized capacitors more than about a microfarad used to be rare and expensive, which is probably why the datasheet shows polarized capacitors being used. Today, you can get 10μF ceramic capacitors for less than $0.30 each.





Edit: As @ThePhoton points out, this regulator may be so old that multi-microfarad ceramic capacitors, with their inherent low ESR, may have been a far-off pipe dream to the engineers writing the datasheet. So this may still be unstable with too low an ESR on its output, so unless you want to test its stability under different operating conditions with the ceramic caps, it may be best to stick to aluminum electrolytics. After all, that's probably what the IC's designers had in mind.






share|improve this answer











$endgroup$



It doesn't usually matter, but be aware that some linear regulators--the popular LM2940 series, for example--may be unstable if the output capacitor's ESR is too high or too low. As the datasheet for your regulator doesn't seem to say anything about that at a glance, it should be fine with any capacitors you pick, but see the edit below for a warning.



Non-polarized capacitors more than about a microfarad used to be rare and expensive, which is probably why the datasheet shows polarized capacitors being used. Today, you can get 10μF ceramic capacitors for less than $0.30 each.





Edit: As @ThePhoton points out, this regulator may be so old that multi-microfarad ceramic capacitors, with their inherent low ESR, may have been a far-off pipe dream to the engineers writing the datasheet. So this may still be unstable with too low an ESR on its output, so unless you want to test its stability under different operating conditions with the ceramic caps, it may be best to stick to aluminum electrolytics. After all, that's probably what the IC's designers had in mind.







share|improve this answer














share|improve this answer



share|improve this answer








edited 53 mins ago

























answered 1 hour ago









HearthHearth

4,5151136




4,5151136








  • 3




    $begingroup$
    The chip might just be so old that when they wrote the datasheet, they didn't consider the possibility that someone would want to use a low-ESR ceramic capacitor for such high values (1 and 10 uF). I'd stick with electrolytic unless I had time to experiment and make sure it stays stable with ceramic over all operating conditions (temperature, input voltage, etc).
    $endgroup$
    – The Photon
    1 hour ago






  • 1




    $begingroup$
    That's a good point, @ThePhoton. Then again, MLCCs are relatively high ESR as ceramics go, and you can get pretty low ESR electrolytics--I'm not sure how they compare, but you do make a good point and I'll add a note to that effect in the answer.
    $endgroup$
    – Hearth
    1 hour ago














  • 3




    $begingroup$
    The chip might just be so old that when they wrote the datasheet, they didn't consider the possibility that someone would want to use a low-ESR ceramic capacitor for such high values (1 and 10 uF). I'd stick with electrolytic unless I had time to experiment and make sure it stays stable with ceramic over all operating conditions (temperature, input voltage, etc).
    $endgroup$
    – The Photon
    1 hour ago






  • 1




    $begingroup$
    That's a good point, @ThePhoton. Then again, MLCCs are relatively high ESR as ceramics go, and you can get pretty low ESR electrolytics--I'm not sure how they compare, but you do make a good point and I'll add a note to that effect in the answer.
    $endgroup$
    – Hearth
    1 hour ago








3




3




$begingroup$
The chip might just be so old that when they wrote the datasheet, they didn't consider the possibility that someone would want to use a low-ESR ceramic capacitor for such high values (1 and 10 uF). I'd stick with electrolytic unless I had time to experiment and make sure it stays stable with ceramic over all operating conditions (temperature, input voltage, etc).
$endgroup$
– The Photon
1 hour ago




$begingroup$
The chip might just be so old that when they wrote the datasheet, they didn't consider the possibility that someone would want to use a low-ESR ceramic capacitor for such high values (1 and 10 uF). I'd stick with electrolytic unless I had time to experiment and make sure it stays stable with ceramic over all operating conditions (temperature, input voltage, etc).
$endgroup$
– The Photon
1 hour ago




1




1




$begingroup$
That's a good point, @ThePhoton. Then again, MLCCs are relatively high ESR as ceramics go, and you can get pretty low ESR electrolytics--I'm not sure how they compare, but you do make a good point and I'll add a note to that effect in the answer.
$endgroup$
– Hearth
1 hour ago




$begingroup$
That's a good point, @ThePhoton. Then again, MLCCs are relatively high ESR as ceramics go, and you can get pretty low ESR electrolytics--I'm not sure how they compare, but you do make a good point and I'll add a note to that effect in the answer.
$endgroup$
– Hearth
1 hour ago













0












$begingroup$

The datasheet application circuit example schematic shows a 1 microfarad polarized capacitor on the input and a 10 microfarad polarized capacitor on the output. Since the values are in the 1 plus microfarad range and the capacitors are shown as polarized, I would guess that the manufacturer (ST) wants you to use electrolytic caps. I guess you could use a tantalum caps, but unless the datasheet specifies tantalum, that would be a needless expense.



The polarized caps shown on the datasheet circuit lead me to believe that electrolytic caps are what are intended. Very few ceramic caps are over 1 microfarad and very few are polarized.






share|improve this answer









$endgroup$









  • 1




    $begingroup$
    Actually, ceramic capacitors of up to hundreds of μF are, while not common, certainly readily available. They're not terribly expensive, either. Ceramic capacitor technology has improved dramatically in the past decade or so.
    $endgroup$
    – Hearth
    1 hour ago






  • 2




    $begingroup$
    I agree with Hearth that you're wrong to say 1 uF and up are rare as ceramics. But I'd still advise OP to stick with electrolytics since older regulator designs depend on a reasonably high ESR in the capacitor to maintain stability. If the datasheet doesn't promise the regulator is stable with low-ESR or ceramic output capacitors, it's not wise to assume it will be.
    $endgroup$
    – The Photon
    1 hour ago
















0












$begingroup$

The datasheet application circuit example schematic shows a 1 microfarad polarized capacitor on the input and a 10 microfarad polarized capacitor on the output. Since the values are in the 1 plus microfarad range and the capacitors are shown as polarized, I would guess that the manufacturer (ST) wants you to use electrolytic caps. I guess you could use a tantalum caps, but unless the datasheet specifies tantalum, that would be a needless expense.



The polarized caps shown on the datasheet circuit lead me to believe that electrolytic caps are what are intended. Very few ceramic caps are over 1 microfarad and very few are polarized.






share|improve this answer









$endgroup$









  • 1




    $begingroup$
    Actually, ceramic capacitors of up to hundreds of μF are, while not common, certainly readily available. They're not terribly expensive, either. Ceramic capacitor technology has improved dramatically in the past decade or so.
    $endgroup$
    – Hearth
    1 hour ago






  • 2




    $begingroup$
    I agree with Hearth that you're wrong to say 1 uF and up are rare as ceramics. But I'd still advise OP to stick with electrolytics since older regulator designs depend on a reasonably high ESR in the capacitor to maintain stability. If the datasheet doesn't promise the regulator is stable with low-ESR or ceramic output capacitors, it's not wise to assume it will be.
    $endgroup$
    – The Photon
    1 hour ago














0












0








0





$begingroup$

The datasheet application circuit example schematic shows a 1 microfarad polarized capacitor on the input and a 10 microfarad polarized capacitor on the output. Since the values are in the 1 plus microfarad range and the capacitors are shown as polarized, I would guess that the manufacturer (ST) wants you to use electrolytic caps. I guess you could use a tantalum caps, but unless the datasheet specifies tantalum, that would be a needless expense.



The polarized caps shown on the datasheet circuit lead me to believe that electrolytic caps are what are intended. Very few ceramic caps are over 1 microfarad and very few are polarized.






share|improve this answer









$endgroup$



The datasheet application circuit example schematic shows a 1 microfarad polarized capacitor on the input and a 10 microfarad polarized capacitor on the output. Since the values are in the 1 plus microfarad range and the capacitors are shown as polarized, I would guess that the manufacturer (ST) wants you to use electrolytic caps. I guess you could use a tantalum caps, but unless the datasheet specifies tantalum, that would be a needless expense.



The polarized caps shown on the datasheet circuit lead me to believe that electrolytic caps are what are intended. Very few ceramic caps are over 1 microfarad and very few are polarized.







share|improve this answer












share|improve this answer



share|improve this answer










answered 2 hours ago









user193589user193589

388




388








  • 1




    $begingroup$
    Actually, ceramic capacitors of up to hundreds of μF are, while not common, certainly readily available. They're not terribly expensive, either. Ceramic capacitor technology has improved dramatically in the past decade or so.
    $endgroup$
    – Hearth
    1 hour ago






  • 2




    $begingroup$
    I agree with Hearth that you're wrong to say 1 uF and up are rare as ceramics. But I'd still advise OP to stick with electrolytics since older regulator designs depend on a reasonably high ESR in the capacitor to maintain stability. If the datasheet doesn't promise the regulator is stable with low-ESR or ceramic output capacitors, it's not wise to assume it will be.
    $endgroup$
    – The Photon
    1 hour ago














  • 1




    $begingroup$
    Actually, ceramic capacitors of up to hundreds of μF are, while not common, certainly readily available. They're not terribly expensive, either. Ceramic capacitor technology has improved dramatically in the past decade or so.
    $endgroup$
    – Hearth
    1 hour ago






  • 2




    $begingroup$
    I agree with Hearth that you're wrong to say 1 uF and up are rare as ceramics. But I'd still advise OP to stick with electrolytics since older regulator designs depend on a reasonably high ESR in the capacitor to maintain stability. If the datasheet doesn't promise the regulator is stable with low-ESR or ceramic output capacitors, it's not wise to assume it will be.
    $endgroup$
    – The Photon
    1 hour ago








1




1




$begingroup$
Actually, ceramic capacitors of up to hundreds of μF are, while not common, certainly readily available. They're not terribly expensive, either. Ceramic capacitor technology has improved dramatically in the past decade or so.
$endgroup$
– Hearth
1 hour ago




$begingroup$
Actually, ceramic capacitors of up to hundreds of μF are, while not common, certainly readily available. They're not terribly expensive, either. Ceramic capacitor technology has improved dramatically in the past decade or so.
$endgroup$
– Hearth
1 hour ago




2




2




$begingroup$
I agree with Hearth that you're wrong to say 1 uF and up are rare as ceramics. But I'd still advise OP to stick with electrolytics since older regulator designs depend on a reasonably high ESR in the capacitor to maintain stability. If the datasheet doesn't promise the regulator is stable with low-ESR or ceramic output capacitors, it's not wise to assume it will be.
$endgroup$
– The Photon
1 hour ago




$begingroup$
I agree with Hearth that you're wrong to say 1 uF and up are rare as ceramics. But I'd still advise OP to stick with electrolytics since older regulator designs depend on a reasonably high ESR in the capacitor to maintain stability. If the datasheet doesn't promise the regulator is stable with low-ESR or ceramic output capacitors, it's not wise to assume it will be.
$endgroup$
– The Photon
1 hour ago


















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