LM393B: High output current Comparator Recommendation

Yang Wu

Expert 3360 points

Part Number: LM393B
Other Parts Discussed in Thread: UCC27517

Hi team,

Do we have high output current Comparator (>=110mA)? Single or dual should be OK.

My customer needs it for high current hall sensing product.

Thanks a lot.

Best regards,

Yang

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 317480 points

This sounds like that post: High output current Comparator

To repeat the unanswered questions from there: Why do you need such a high output current? Does the output need to sink high current source high current or both? What is the output voltage range?

0 Yang Wu over 4 years ago in reply to Clemens Ladisch

TI__Expert 3360 points

Hi Clemens,

I don't get detailed info from customer about the reason of such a high output current.

The output only needs source current with voltage level < 5V.

Thanks a lot.

Best regards,

Yang

0 Clemens Ladisch over 4 years ago in reply to Yang Wu

Guru 317480 points

I still recommend any suitable comparator combined with the UCC27517 (whose minimum V_CC is 4.5 V).

0 Yang Wu over 4 years ago in reply to Clemens Ladisch

TI__Expert 3360 points

Hi Clemens,

Thanks a lot. Let me check with customer.

Best regards,

Yang

+1 Paul Grohe over 4 years ago in reply to Yang Wu

TI__Guru 61356 points

Hi Yang,

As Clemens stated, we do not have any comparators capable of sourcing >100mA.

All our comparators are low power, typically in the 5-20mA sourcing range. No "Power" comparators.

Because they are low power, they are in small (and very small) packages that limit the power dissipation.

Typically an external discrete pass transistor (BJT or MOSFET) is used when high currents must be switched.

If below 5V, then a simple high-side P-Channel MOSFET can be used (just watch the MOSFET Vgs max).

0 Yang Wu over 4 years ago in reply to Paul Grohe

TI__Expert 3360 points

Hi Paul，

thanks for your reply. I also suggest customer to have a BJT solution and wait customer's feedback.

Best regards,

Yang

0 kai klaas69 over 4 years ago in reply to Yang Wu

Guru 140200 points

Hi Yang,

high switching output currents can make trouble when considering ground bounce within the package. Across the bondwire resistance and especially inductance high dynamic voltage drops can occur during the switching which can severely shift the threshold voltage. Instability can be the consequence.

So it's not wise to have the comparator section and switching section in the same package unless the switched output currents are only rather modest. The far better way is to use two separate packages.

Kai

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LM393B: High output current Comparator Recommendation