Space & High Reliability Forum (Read Only) - Recent Threads

TLK2711-SP: Is there an EYE diagram mask definition available?

Jeroen van der Velden — Thu, 01 Mar 2018 07:08:28 GMT

Part Number: TLK2711-SP

Dear TI,

I would like to setup a mask test on my oscilloscope to verify the eye diagram of the TLK2711 chipsets on my board.

Is there a definition available of how the diamond shape mask should look like at e.g. minimum and maximum operating frequency?

I can try to define it myself by using the min/max voltage levels, rise/fall times and allowed jitter, but if that kind of information is already available I would really like to have it.

Many thanks and best regards,

Jeroen van der Velden

RE: TLK2711-SP: Is there an EYE diagram mask definition available?

Wade Vonbergen — Thu, 04 Apr 2019 10:35:38 GMT

It was noted that this eye was based on single ended, and not differential.

The correct estimated mask for the full differential pk pk input for receiver would be 2x in height.

TPS7A4501-SP: power up over voltage

assaf matia — Sun, 19 Aug 2018 12:52:36 GMT

Part Number: TPS7A4501-SP

hi,

feedback resistors are calculated to 3.3V, but when power up the device there is overshoot to 3.6V and then dropping to 3.3V. the time from overshoot until stable is about 20uS

1. is this normal behaviour?

2. can i do anything to fix this?

the resistors I am using are 5.32K, 3.01K and compensation capacitor of 220pF.

I tried to increase the compensation capacitor to 820pF but no change.

please advise.

Thanks

RE: TPS7A4501-SP: power up over voltage

Daniel Hartung — Thu, 13 Sep 2018 11:12:05 GMT

Hey Assaf,

Were you able to take measurements on the board?
Did the issue resolve itself?

Thanks,
Daniel

TPS73201-EP: The overcurrent limit is over spec

Cage Chen — Mon, 30 Jul 2018 02:38:38 GMT

Part Number: TPS73201-EP

Hi expert,

I got a feedback from customer talking about overcurrent limit of TPS73201-EP.

In the datasheet, there is a range of it, which is 250mA ~ 600mA.

You can see the waveform captured by customer, it is limited by 634mA which is over spec.

Can you explain how does it happen? It is a 5V to 3.3V design.

Thanks a lot.

Best regards, Cage.

RE: TPS73201-EP: The overcurrent limit is over spec

Daniel Hartung — Tue, 04 Sep 2018 07:45:42 GMT

Hey Cage,

Vin=3.3 V and Vout = 3 V satisfies (1) Minimum VIN = VOUT + VDO or 1.7 V.

The reason the customer is seeing it as higher is actually due to the test condition at the top of the table which says VIN = VOUT(nom) + 0.5 V.

This is at the top of the table 6.5 on page 6 of the datasheet.

Thanks,
Daniel

RE: TPS73201-EP: The overcurrent limit is over spec

Cage Chen — Mon, 03 Sep 2018 02:16:35 GMT

Hi Daniel,

Yes, Vin=3.3V, Vout=3V.

So the datasheet should need to add extra test conditions in the item of output current limit.

Because in datasheet, the test conditions is only showing Vout=0.9xVout(nom).

Thank you.

Best regards, Cage.

RE: TPS73201-EP: The overcurrent limit is over spec

Daniel Hartung — Mon, 03 Sep 2018 02:02:08 GMT

Hey Cage,

Please show the customer footnote one in the datasheet for the table.

(1) Minimum VIN = VOUT + VDO or 1.7 V, whichever is greater

Have their tests been with <1.7 V between Vout and Vin?

Thanks,

Daniel

RE: TPS73201-EP: The overcurrent limit is over spec

Cage Chen — Fri, 31 Aug 2018 20:01:57 GMT

Hi Daniel,

Yes, the current probe is very accurate, and even scope is very accurate.

After they removed output cap, the overcurrent limit is just slightly reduced from 624mA to 612mA.

Customer just needs a explanation why it is over spec.

Thank you.

Best regards, Cage.

ps, Customer also mentioned one thing, if the difference between Vin and Vout is small, the current limit will be easy to over 600mA, if it is big, the current limit will be about 580mA or smaller.

INA271-HT: INA271SHKQ

tom webb — Thu, 12 Jul 2018 21:18:11 GMT

Part Number: INA271-HT

i AM LOOKING FOR THE LEAD COMPOSITION AND THE LEAD FINISH FOR THIS PART AS IT IS NOT ON THE DATA SHEET

REF5025-HT: REF5025SHKQ

tom webb — Thu, 12 Jul 2018 21:20:35 GMT

Part Number: REF5025-HT

I AM LOOKING FOR THE LEAD COMPOSITION , THE LEAD FINISH AND THICKNESS FOR THIS PART

alternate device for SNJ55464JG

Aaron Spaete — Mon, 06 Aug 2018 17:53:59 GMT

Team,

My customer has the following inquiry.

My customer is requesting assistance with locating an alternate device for the discontinued SNJ55464JG - (NOR Gate Based Peripheral Driver, 2 Driver, 0.5A, BIPolar, CDIP8)

Thanks,

Aaron

SN74LVC1T45-EP: leakage in power domains

Emma Wang — Mon, 20 Aug 2018 10:01:37 GMT

Part Number: SN74LVC1T45-EP

There is leakage in the VCCA and VCCB power domains for SN74LVC1T45.

if the 74LVC1T45-EP chip has improved this problem, or it still exists?

If there is a buffer with no leakage models in the two power domains

TPS7A4501-SP: Powerup Overshoot

Itai Eden — Sun, 19 Aug 2018 12:59:47 GMT

Part Number: TPS7A4501-SP

Hello,

I'm designing a 3.35V LDO using the TOS7A4501-SP.

During powerup, I observe an overshoot to 3.55V. The overshoot stabalizs after ~20usec.

I tried different values on the compensation capacitor (C3 in figure 24 of the datasheet) from 220pF to 1000pF and no change was observed in the overshoot.

R1=3.01K

R2=5.33K

Do you have any recommendations on how to reduce the overshoot?

Regards,

Itai

RE: INA271-HT: INA271SHKQ

Kirby Kruckmeyer96848 — Fri, 31 Aug 2018 13:30:00 GMT

The Au plate thickness is 60 to 225 micro inches.

RE: REF5025-HT: REF5025SHKQ

Kirby Kruckmeyer96848 — Fri, 31 Aug 2018 13:28:15 GMT

TheAu plate thickness is 60 to 225 micro inches.

RE: alternate device for SNJ55464JG

Wade Vonbergen — Fri, 31 Aug 2018 10:42:29 GMT

Aaron, I did not get any additional information on alternate device.
Marking this post as closed.
Regards,
Wade

RE: SN74LVC1T45-EP: leakage in power domains

Wade Vonbergen — Fri, 31 Aug 2018 10:41:20 GMT

Let me know if you need further information. Marking this post as closed.
Regards,
Wade

RE: TPS73201-EP: The overcurrent limit is over spec

Daniel Hartung — Fri, 31 Aug 2018 10:27:05 GMT

Hey Cage,

Was the customer able to take these measurements?

Thanks,
Daniel

RE: TPS7A4501-SP: Powerup Overshoot

Daniel Hartung — Fri, 31 Aug 2018 10:25:18 GMT

Hello Itai,

Are there any updates on the previous questions?

If there are no updates I will close the thread.

Thanks,
Daniel

UC1845: how to pick RT/CT values

Yue Wei91 — Tue, 28 Aug 2018 20:28:55 GMT

Part Number: UC1845

Hi,

The UC1845 datasheet section 8.3.1.4 RT/CT provides a recommended range for timing resistor R_RT (5Kohm-100Kohm) and timing capacitor C_CT (1nF-100nF), so does it mean the recommended maximum oscillating frequency f_OSC is 1.72/(5Kohm*1nF) = 344KHz? If I want to obtain higher frequency, say 450KHz, is it recommended to keep 5Kohm RT and reduce CT, or keep 1nF CT and reduce RT? Thank you.

SM320F28335-EP: Need something with Higher Switching Frequency for SiC

David C — Tue, 28 Aug 2018 16:09:42 GMT

Part Number: SM320F28335-EP

Hello,

We have been using TI F2812 or TI F28335 in all our motor drive designs. Now the SiC power switch is the trend in the motor drive industry. SiC allows us to switch at much higher frequency (at least two times) . But this imposes more stringent requirement on the horse power (speed) of the micro-controller.

We would like to know what more powerful processors TI offers with -55 to 125C temperature rating. Otherwise we will be forced to switch to ARM or FPGA solutions.

Regards,

David

RE: UC1845: how to pick RT/CT values

Yue Wei91 — Tue, 28 Aug 2018 17:35:35 GMT

Okay, Thank you.

RE: UC1845: how to pick RT/CT values

Daniel Hartung — Tue, 28 Aug 2018 17:25:25 GMT

Hey Yue,

I believe that the comment in the pin functions table is simply referring to the 5k recommendation, but you can always be safe and use capacitance lower for now.

I believe the real issue lies in the fact the clock ramp signal will become somewhat non-linear due to being an RC curve with really small values used. This may cause problems the clock changing over temperature, but that is something that would need to be tested in circuit.

Thanks,
Daniel

AM26LV32E-EP: Can I run this at 24Vpp or is there a a better solution?

David C — Tue, 28 Aug 2018 16:06:24 GMT

Part Number: AM26LV32E-EP

Hello,

We are moving differential serial data busses into +3.3V single ended into the FPGA

Right now we've selected the AM26LV32E-EP.

This works perfectly for our 10Vpp bus however we have one bus that does 0 to 16V and another that can do 24Vpp. The legacy device a 26LS33 allowed for 30Vpp on the input voltage, the 26LV32 part recommends 14Vpp but does allow up to 28Vpp, however that is absolute max which increases risk of damaging the part.

So two fold question, how big a risk is it to be constantly running the device at 24Vpp, and is there any other solution that can allow for the high differential voltages?

I did try looking at some high speed comparators but the 24Vpp bus runs at a min of 1MHz, so couldn’t find anything quick enough that met the speed required.