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# SN6505B: What is Ron @ TA=125℃?

Part Number: SN6505B

Hello team,

Could you tell me typical value about the Ron @ TA=125℃?

Best regards,
Ochi

• Hi Ochi-san,

R(ON) of SN6505 output switch has dependency on multiple factors like voltage, current, temperature & process. Hence, to quote a value at TA = 125C the values of other parameters would also be required.

We expect the value of R(ON) to be the lowest at TA = 125C. If customer is interested in finding out the lowest R(ON) value then I can say that the lowest R(ON) value can be <0.16Ω. Let me know if this answers your question, thank you.

Regards,
Koteshwar Rao

• In reply to Koteshwar Rao:

Hi Rao-san,

Do you mean that the minimum value of  R(ON) @ Ta=125℃ can be <0.16Ω? Or, do you mean that the minimum value of  R(ON) in all recommended operation range can be <0.16Ω?

The customer considers the typical value of Ron @ TA=125℃.
Could you tell me what values of other parameters are required to know Ron typ. @ TA=125℃? If it is possible to know them, I will send email to you after asking them to the customer.

Best regards,
Ochi

• In reply to Yoshiki Ochi:

Hi Ochi-san,

The overall minimum value of R(ON) is going to happen when TA = 125C, hence the minimum value of R(ON) for TA = 125C and TA = -40C to 125C is going to be <0.16Ω.

Like I mentioned earlier, this value also depends on supply voltage, drain current and temperature. We do not have characterization data for all voltage, current temperature values and hence it may not be possible to quote exact R(ON) value range for customer test conditions. I would recommend to use 0.16Ω as the value for TA = 125C assuming drain current of 1A.

Do you know why does customer need this data? I do not think a small variation in this value is going to impact anything significantly. Let me know, thanks.

Regards,
Koteshwar Rao

• In reply to Koteshwar Rao:

Hello Rao-san,

Could you tell me the reason why SN6505-Q1 has lower Ron if it is higher temperature?
I refer to another kind device (HSS) and it has different characteristics from that of SN6505-Q1. That is, higher temperature is, higher Ron is.

Could you tell me that reason and how to operate so?

Best regards,
Ochi

• In reply to Yoshiki Ochi:

Hi Ochi-san,

Thanks for your inputs. The behavior of R(ON) actually depends on the design and the transistors used in the design. It can vary differently for different devices, hence it is normal to see that R(ON) variation of other devices can be very different from SN6505.

I had an internal discussion with the design team and reviewed some internal data. The usual observation is that BJT transistors have negative temperature co-efficient, due to which the R(ON) will go lower with increasing temperature. While the MOSFETs usually have positive temperature co-efficient and the R(ON) of MOSFETs will go higher with higher temperature.

SN6505 uses MOSFETs and the internal design is also such that the R(ON) of these MOSFETs goes higher with higher temperature, just like the TPS1H000. Apologies for giving out incorrect information in my earlier posts, please ignore the information I have shared in my earlier posts.

To conclude, R(ON) max of SN6505 at TA = 125C will be 0.25Ω with VCC = 4.5V and will be 0.45Ω with VCC = 2.25V. This I have verified with the design team and the test data, hence this is accurate. Thanks.

Regards,
Koteshwar Rao

• In reply to Koteshwar Rao:

Hello Rao-san,

Thank you for your help! I could understand and learn the characteristics of BJT transistors and MOSFETs!

Best regards,
Ochi

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