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WICED Smart Bluetooth

Anonymous
Not applicable

How many volt (at VBAT) is the voltage condition of the attached current consumption table for BCM20737S?

And the sleep current 12uA (nominal)  is correct??

[20737S-DS100-R.pdf] page 13

QS_20150521-135605.png

Additionally, the above one [20737S-DS100-R.pdf] and the following document [WICED-Smart-DG100-R.pdf] has huge difference regarding sleep current. Which is correct for BCM20737S?

OR, WICED-Smart-DG100-R.pdf table 2 is not for BCM20737S?

I always confused about current consumption because BCM20737 related documents seem fragmented.

Please correct and keep it updated if the current data sheet (20737S-DS100-R.pdf) is obsoleted otherwise everyone must be confused.

[WICED-Smart-DG100-R.pdf] page 12

QS_20150521-140207.png12

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1 Solution
MichaelF_56
Moderator
Moderator

Forgive my initial response as I was not familiar with the current numbers published within the WICED Smart Sleep/Deep-Sleep Explanation and Techniques Design Guide

This is a newer document that I am not as familiar with...

I am checking with the author of that document now to confirm both the operating voltage used during those measurements and whether or not an external DC-DC was leveraged. At this point I am assuming these tests leveraged a different test setup as compared to the datasheet.

Related to this topic, it's important to understand the following about the current values provided in both datasheets (SoC and Module).

1.

All datasheet values apply to the SoC alone, which is implemented as raw die inside of the SIP module.  So in addition to chip current, there would also be some added current from the other internal components inside the SIP module (EEPROM, Xtal).

2.

As stated in the datasheets for both SoC and SIP module:

Note: With an optional DC-DC (90% efficient) converter at 3V, the current between the battery terminals (shown in Table 5) are about 50% lower than their nominal values at the default operating voltage (1.62V).

So both 3V and an external DC-DC are ideal circumstances.

No DC-DC, then expect higher current, up to 50% more than what's published.

Today, there is no SIP module with external DC-DC capabilites, but that will change with the BCM20737L, which will be released most likely in the upcoming quarter.

2a.

3V is also optimal for lower current since reductions in supply voltage yield increases in current.

3.

As boont mentions, the TAG3 is not an optimal tool to measure current for a variety of technical reasons (i.e. bad GND plane, lacks a means to minimize current seen from periperhals, etc.).  With that said, there is a new TAG board due to be released in Q3 that addresses these shortcomings and customers will be able to use it for accurate current measurements.

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12 Replies
MichaelF_56
Moderator
Moderator

The values shown in that table reflect the SoC current and assume an optional DC-DC (90% efficient) converter and operation at 3V.

The new 20737L SIP module will allow the use of an external DC-DC converter.

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Anonymous
Not applicable

Let me confirm it.

The current consumption table is measured with BCM20737 with an optinal DC-DC? Is the table not for BCM20737S?

Or, you mean the 3V is applied to VBAT of BCM20737S directly to use internal LDO?

Please clarify.

And the second question, which current value is correct for BCM20737S sleep mode?  12uA? or 30uA?

And please give me the data sheet of 20737L.

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MichaelF_56
Moderator
Moderator

Current values shown in module datasheet are for the SoC.

The 20737L will be released in Q315.

Picture1.png

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Anonymous
Not applicable

Thanks.

Is the difference between BCM20737S and BCM20737L only the LDO insertion?

Please answer the second question, which current value is correct for BCM20737S sleep mode?  12uA? or 30uA?

We measured 33uA@2.5V with TAG3 eval board using our high precision current monitor.

Does it sound like right value?

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Anonymous
Not applicable

Additionally, please give me the pin assignments of BCM20737L. I'll check the compatibility.

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Anonymous
Not applicable

mwf_mmfae
Please answer the second question, which current value is correct for BCM20737S sleep mode?  12uA? or 30uA?

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MichaelF_56
Moderator
Moderator

My understanding is that this value (Sleep) is between 12uA and 19.2uA.

This is what's noted in each of the SIP module and SoC datasheets.

I'm not familiar with the document you are referencing, so I have asked the local team dedicated to supporting your company to respond.

Unfortunately, I do not have access to the pinout for the new 20737L

nsankar joji

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Anonymous
Not applicable

Thanks a lot.

But we have measured 33uA@2.5V input to VBAT with BCM92073X_LE_KIT(=TAG3 Board; Broadcom official eval kit of BCM20737) in sleep mode, no advertisement.

It's far higher than 12uA.

And [WICED-Smart-DG100-R.pdf] shows the sleep current is 30uA.

The document is here.WICED Smart Sleep/Deep-Sleep Explanation and Techniques Design Guide


So I doubted that the 12uA is wrong or not for BCM20737S.


Do you know why the sleep currents are described differently as 12uA and 30uA???

mwf_mmfae

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BoonT_56
Employee

I wouldn't read too deep into the figures from the tag3 as it has not been a reliable platform for current measurement, although I agree that the 30uA reading in the sleep state has to be further elaborated in the new document.

BCM20736S Sleep Example Firmware - Current Seems High

joji

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MichaelF_56
Moderator
Moderator

Forgive my initial response as I was not familiar with the current numbers published within the WICED Smart Sleep/Deep-Sleep Explanation and Techniques Design Guide

This is a newer document that I am not as familiar with...

I am checking with the author of that document now to confirm both the operating voltage used during those measurements and whether or not an external DC-DC was leveraged. At this point I am assuming these tests leveraged a different test setup as compared to the datasheet.

Related to this topic, it's important to understand the following about the current values provided in both datasheets (SoC and Module).

1.

All datasheet values apply to the SoC alone, which is implemented as raw die inside of the SIP module.  So in addition to chip current, there would also be some added current from the other internal components inside the SIP module (EEPROM, Xtal).

2.

As stated in the datasheets for both SoC and SIP module:

Note: With an optional DC-DC (90% efficient) converter at 3V, the current between the battery terminals (shown in Table 5) are about 50% lower than their nominal values at the default operating voltage (1.62V).

So both 3V and an external DC-DC are ideal circumstances.

No DC-DC, then expect higher current, up to 50% more than what's published.

Today, there is no SIP module with external DC-DC capabilites, but that will change with the BCM20737L, which will be released most likely in the upcoming quarter.

2a.

3V is also optimal for lower current since reductions in supply voltage yield increases in current.

3.

As boont mentions, the TAG3 is not an optimal tool to measure current for a variety of technical reasons (i.e. bad GND plane, lacks a means to minimize current seen from periperhals, etc.).  With that said, there is a new TAG board due to be released in Q3 that addresses these shortcomings and customers will be able to use it for accurate current measurements.

View solution in original post

Anonymous
Not applicable

Thanks a lot for the clarification.

So, that means you have never measured BCM20737S (SiP) current consumption and you have no data about it, right?

Anyways, I'd like to know the 36uA in 2.5V@VBAT of our PCB with BCM20737S is possible value or not.

BTW, we have already made our PCB for BCM20737S and we have no option to remake it for BCM20737L because of our schedule.

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MichaelF_56
Moderator
Moderator

Your local Broadcom distributor will be contacting you to follow up on this topic.

nsankar

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