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

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
Other Parts Discussed in Thread: TMS320F28377D-EP, TMS320C28346

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

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.

Single Event Latchup information for TI devices

marilingaiah nl — Mon, 27 Aug 2018 20:04:06 GMT

Hi,

I have list of TI devices for which i am look for Single Event Latchup information.

Could anyone route me to right channel or concern person, from where i can get SEL infromation.

Regards

Maril

TPS7H1101A-SP: Power Dissipation Calculation Using RθJC

LALIT VERMA — Mon, 27 Aug 2018 06:52:26 GMT

Part Number: TPS7H1101A-SP

Hi All,

We are planning to use TPS7H1101A-SP for our project with below specifications:

Vin = 5V

Vout= 3.5V

Iout = 2.376A

With these specifications total power dissipation comes out to be 3.564W.

In TPS7H1101A-SP datasheet RθJC = 0.6°C/W but RθJA is not given. Generally power disspation is calculated using RθJA.

So my question is how to calculate maximum power dissipation of TPS7H1101A-SP using RθJC.?

And can we use TPS7H1101A-SP with specifications mentioned above.

SN54LS374: Difference in SN54LS374J and SNJ54LS374J

KONDAMMA Nakkireddy — Mon, 27 Aug 2018 06:21:06 GMT

Part Number: SN54LS374

We have procured the IC SN54LS374J. However we have received item SNJ54LS374J

As per datasheet both specifications are same. I need clarification

a) what is the significance of letter 'J"?

b) What is the difference between these two parts SN54LS374J and SNJ54LS374J

Regards

Kotresh Kumar DS

TPS76901-HT: Start-Up; ramp rate; LDO

Kenneth Lee — Mon, 27 Aug 2018 02:49:57 GMT

Part Number: TPS76901-HT

Hello Team,

My customer is asking y-axis scale of below start-up waveform.

The requirement of ramp rate is between 0.165 ~ 33 V/ms.

Customer will use this LDO for making 2.5V from 3.3V input.

Can this meet the requirement? Thank you in advance.

DS26F31MQML-SP: DS26F31MQML-SP

user5350535 — Sat, 25 Aug 2018 09:28:26 GMT

Part Number: DS26F31MQML-SP
Other Parts Discussed in Thread: AM26LS31, DS96F172MQML, DS96F174MQML

Can you tell me the output current for OUT PINS. I am using AM26LS31, the output current 20mA is lower for our application , we want to use the IC with high output driver,can you give us some suggest?

TKS

Unitrode Bridge Diode 679-2

Marvin Tennison — Fri, 24 Aug 2018 15:44:03 GMT

Request availability of Unitrode Bridge Diode PN 679-2 or PN 127889. The Unitrode Corp. page indicates that TI purchased them.

CD4023B: Difference between CD4023BF and CD4023BF3A

Athun Siva — Fri, 24 Aug 2018 07:33:21 GMT

Part Number: CD4023B

Can somebody tell the differences between CD4023BF and CD4023BF3A ? Is there any change in Package or electrical spec?

Also can we use this part (CD4023BF/CD4023BF3A ) as a replacement for old Motorolla part # M38510/05003BCA (discarding the fact that it is Milgrade version). Is it compatible?

TPS50601-SP: Master-Slave Mode performed right or not and Purpose of Schottky Diodes in EVAL Board.

LALIT VERMA — Thu, 23 Aug 2018 17:02:22 GMT

Part Number: TPS50601-SP
Other Parts Discussed in Thread: TPS54620, TPS50601A-SP

Hi All,

We are using TPS50601-SP in Master-Slave Mode.

Vin=5v , Vout=1V , Iout= 6A

For this we are following below steps:-e2e.ti.com/.../TPS50601_2D00_PARALLEL.pdf

The RT pin of the master device is left floating.
The RT pin on slave device is connected to a 95.3k resistor so that the frequency of the slave device is 500kHz.
Only a single feedback network is connected to the VSENSE pin of the master device. No resistor divider is connected to slave VSENSE pin. Although both VSENSE pins are shorted.
SYNC pin of the master is connected to the SYNC pin of the slave device.
Only a single compensation network is connected to the COMP pin of the master device. Both COMP pins are shorted.
Only a single soft start capacitor is connected to the SS pin of the master device Both SS pins are shorted.
Only a single enable resistor divider is connected to the EN pin of the master device. Both EN pins are shorted.
Master device controls the compensation, soft start and enable networks, the factor of 2 is taken into account when calculating the components associated with these pins.

These points are from application note "TPS54620 Parallel Operation".

Are these steps right or do we need to use separate feedback divider for output at both TPS50601-SP and same for COMP,EN etc and then shorted these pins.

Also in EVAL board of TPS50601-SP Schottky diodes are used from Vin to Boot and PH to Gnd. Are schottky diodes compulsory or we can ignore them?

Attached is the schematic please review it and share your comments.

Early response will be highly appreciated.

Thanks

LMH5401-SP: commercial and space die the same?

Brian Antheunisse — Thu, 23 Aug 2018 16:31:09 GMT

Part Number: LMH5401-SP
Other Parts Discussed in Thread: LMH5401

Hi guys,

My customer is currently using the LMH5401 in a commercial grade lab prototype design, and the plan is now to build a space grade board. Is the LMH5401-SP the same die with the package powering the gain bandwidth product?

Thanks,

Brian

MC1558M: MC1558JG and MC1558JGB

Errol Leon6 — Wed, 22 Aug 2018 17:31:36 GMT

Part Number: MC1558M

Hello,

My customer was wondering what the difference is between MC1558JG vs. MC1558JGB. Is there a difference testing between the two ?

Thank you!

Errol Leon

Texas Instruments

Field Application Engineer

UC2854B-EP: How to calculate Rsp resistor using current transformer with positive output

Ricardo Cervantez — Wed, 22 Aug 2018 15:06:46 GMT

Part Number: UC2854B-EP

In this document on page 16 figure 11.
I'm not able to find how to calculate the value Rsp?

Is the resistor Rsp the same value as Rs?

UC2625-EP: UC2625ep EV board application

user5034529 — Tue, 21 Aug 2018 10:59:20 GMT

Part Number: UC2625-EP
Other Parts Discussed in Thread: UC3625,

This is Max.koh in korea

we will use to Motor driver ic for BG65X50CI with Motor.

So we are under review UC2625ep for them.

Could you please sent me the UC2625ep EV board Application (included sehematic for EV board)

thanks,

Max.koh

ADS5444-SP: Gerber files

Bonzai — Mon, 20 Aug 2018 17:29:57 GMT

Part Number: ADS5444-SP

Hi,

does anyone have the geber files or board files of the eval module for ADS5444-SP?

Thanks,

Thien

DP83848-EP: Tx Differential pair short circuit behavior

Benjamin EYMARD — Mon, 20 Aug 2018 10:28:29 GMT

Part Number: DP83848-EP

Hello,

For robustness validation, I have to prove that the power supply of our equipment will not be perturbed if a short circuit happens between the pins of the Tx pair. The harm would be that if such a short-circuit occurs, the DP83848-EP disrupts the behavior of the others chips by lowering the power supply voltage while trying to drive the Tx pair correctly.

From the datasheet, I've learned that the maximal current for 100Base-TX is 81 mA, so I'm guessing that if a short-circuit occurs, the current would overpass this limit and the port would be damaged. But is there a way to be absolutely certain that the damaged port would generate an open-circuit instead of a short -circuit ?

Also, does the DP83848-EP have any protection on its outputs pins ?

Thanks.

Best Regards.

Benjamin

SN74LVC1T45-EP: leakage in power domains

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

Part Number: SN74LVC1T45-EP
Other Parts Discussed in Thread: SN74LVC1T45

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

OPA549-HIREL: Request the Lead Forming Data & Recommend the Thermal Pad.

Louis Han15 — Mon, 20 Aug 2018 08:04:01 GMT

Part Number: OPA549-HIREL

hello

Please Can you Recommend the Lead Forming for using SMD Type?

or Can you tell me the values of a, b, c in the figure?

Also Can you Recommend the Thermal Pad Spec?(Meterial, Manufacture)

Regards.

TPS7H1201-HT: TPS7H120

john kelly — Mon, 20 Aug 2018 06:01:08 GMT

Part Number: TPS7H1201-HT

Hello, I am looking for an alternative for the TPS7H1201SHKS. for ttesting I can use a 125C part

Thanks

John

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

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

TPS76825-EP: TPS76825-EP

munir shoga — Sat, 18 Aug 2018 04:09:03 GMT

Part Number: TPS76825-EP

Hi Is this made with CMOS or bipolar technology

Is there radiation data on this part

TPS76801-EP: TPS76801-EP

munir shoga — Sat, 18 Aug 2018 04:04:47 GMT

Part Number: TPS76801-EP

Hi,

Is this designed with CMOS or bipolar technology

Is there any radiation data on this part

TPS7A4501-SP: Single Event Effects

Hugh ODonnell — Fri, 17 Aug 2018 22:17:39 GMT

Part Number: TPS7A4501-SP

Forum indicates you have tested for single event effects but report is not posted online. Can I get a copy?