Logic forum - Recent Threads

SN74LVC138A: Electrical connection for center pad?

Ronnie Gaensli — Fri, 23 Apr 2021 13:05:29 GMT

Part Number: SN74LVC138A

For the RGY package, the datasheet doesn't clearly specify which electrical net the center / thermal pad shall be connector to. I'd assume GND but is this correct?

Student Software license

Arley Celis — Fri, 23 Apr 2021 12:45:55 GMT

I need help about this matter:

In 2015, I bought the product TI-Nspire CX II CAS but I forgot my license number. The problem is that I don't have the packing product and I lost the bill.

I need to have the TI-Nspire CX CAS Student Software for teaching maths to my students using the desktop sharing option on my computer.

Thank you for your attention
Kind regards.
Arley David Celis Vargas

SN74AXC4T774EVM: B2 line not functioning as expected in RSV package whicle works fine with PW

Adarsh Chengot Poonthottathil — Fri, 23 Apr 2021 10:51:46 GMT

Part Number: SN74AXC4T774EVM

Hallo,

1. Very recently I started using SN74AXC4T774EVM for SPI lines between a microcontroller (3V) and a sensor(1.8V). I am receiving proper signals as expected from PW package but not from RSV package. I was not able to find any difference in configuration of the two package in the user guide. DIR1, DIR2 and DIR3 are connected to VCCA using pull up (A->B), while DIR4 is grounded (B->A).

My connection is accordingly.

VCCA = 3V

VCCB = 1.8V

A1-> Chip select

A2-> MOSI

A3->CLOCK

A4->MISO

When I am using RSV package, I am only able to receive proper signal from B1,B3 and B4. While the B2 signal line is corrupted with some noise of ground issue, which I am not able to identify. When using PW package with the same configuration, all signal lines looks good.

Here are the screenshots from my scope.

This is the MOSI line from A2.

This is the MOSI line from B2. as you can see the signal is not restored.

What could be the reason for such a behavior? The PW package is working properly.

Thank you for your time.

with regards,

Adarsh

SN74LV14A: what is the input transition rate of SN74LV14A?

Hung Ching Hsu — Fri, 23 Apr 2021 07:55:30 GMT

Part Number: SN74LV14A
Other Parts Discussed in Thread: SN74LV540A

Hi Team

My customer wants to know the input transition rate of SN74LV14A. It is not shown in datasheet.

I found following material showing LV family have 100ns/V(max) input transition rate.

https://www.ti.com/lit/wp/slla364a/slla364a.pdf#page=2

Is this still true for SN74LV14A? I am asking because it has schmitt trigger, customer wonders if there's any difference for input transition rate with and without schmitt trigger.

For example, SN74LV540A, which have no schmitt trigger, shows 100ns/V input transition rate at Vcc=3V to 3.6V condition.

Thanks.

Regards,

LSF0204: Questions for LSF0204

Max Guan — Thu, 22 Apr 2021 15:27:20 GMT

Part Number: LSF0204

Hi team,

Some questions from my customer evaluating LSF0204 in the design as I2C level shifter (also isolation).

1. As the EN follow the logic of VrefA, will there be leakage from An to Bn if we only pull-high Vrefn (and leave VrefB 0V)?

2. If customer also plans to use LSF0204 as the GPIO level shifter, where the GPIOs are push-pull outputs, do we need the external pull-high voltage rail any more? Or we need pull-high on the Bn side only when An side is push pull GPIO output?

Thanks

Max

TXS0108E: Level translator for MII interface

Abhishek — Thu, 22 Apr 2021 11:21:02 GMT

Part Number: TXS0108E
Other Parts Discussed in Thread: DP83848J, , SN74LVC8T245, SN74AXC8T245

Hello,

I am using DP83848J for Ethernet application. Microcontroller works at 1.8V and need to use level translator for the MII interface.

Is TXS0108E a good choice for MII interface or any other application specific level translators are available from TI.

Thank you,

Abhi

SN74AVC8T245: is that 3.3V to 5.5V used

vasanth kumar78 — Thu, 22 Apr 2021 05:08:07 GMT

Part Number: SN74AVC8T245
Other Parts Discussed in Thread: SN74LXC8T245

HI,

can i use SN74AVC8T245 IC for 3.3V to 5V voltage logic level translator ?. since datasheet mentioned that allows for universal low-voltage bidirectional translation betweenany of the 1.2-V,1.5-V,1.8-V,2.5-V,and3.3-Vvoltage nodes.

Please clarify to me , whether i can use for bidirectional 3.3V 3.3V to 5V voltage logic level translator.

SN74ALS642A-1: a question regarding the interpretation of the data sheet of SN 74 ALS 642 A.

Terao Terao — Thu, 22 Apr 2021 04:11:24 GMT

Part Number: SN74ALS642A-1

Is the IOL low-level output current of SN 74 ALS 642 A -1 NSR and SN 74 ALS 642 A -1 DW 24 mA or 48 mA?

Is this current per pin of the IC or the whole IC?

SN74AHC245: Vin(signal) operating voltage

Roy Chou1 — Thu, 22 Apr 2021 01:45:28 GMT

Part Number: SN74AHC245
Other Parts Discussed in Thread: SN74AHC541

Hi Team,

In datasheet, I only find the recommended operating voltage(OE/DIR) is 0-5.5?

May I know the recommended operating Vin(signal)? 0V-7V? or it's the same as 0-5.5 like OE/DIR?

Roy

SN74AXC4T245: Confirmation needed for using SN74AXC4T245 for 2 pairs of UART and take SN74AVC4T245 as alternative

Tim Chu — Wed, 21 Apr 2021 06:53:41 GMT

Part Number: SN74AXC4T245
Other Parts Discussed in Thread: SN74AVC4T245

Hi there,

Currently I'm studying multiple pairs of 3.3V to 1.8V UART level shift option for my design, so far my plan is use SN74AXC4T245 for each two pairs of UART, and take SN74AVC4T245 as the alternative part in my BOM since both these two specification should meet my design request.

But since I don't have the experience of using these two product, can anyone help reviewing this kind of design is feasible? Especially of taking the SN74AXC4T245 and SN74AVC4T245 as the alternative for each other.

Here's the block diagram, please kindly help review it if there's anything should be modified, thanks in advance!

Tim

SN74AXC8T245: Level translator for SPI interface

Abhishek — Wed, 21 Apr 2021 06:39:57 GMT

Part Number: SN74AXC8T245
Other Parts Discussed in Thread: SN74AXC4T774

Hello,

Can I use SN74AXC8T245 part for SPI interface.

Thank you,

Abhi

MAX14591ETA+T P-P solution from TI

Sean Liao (Yu-Sheng) — Wed, 21 Apr 2021 02:10:39 GMT

Other Parts Discussed in Thread: TXS0102, LSF0102

Hi team,

Pls knidly suggest TI P-P solution to replace MAX14591ETA+T, thanks a lot!

SN74F38: ESD HBM

Mark Philip Felipe — Tue, 20 Apr 2021 23:11:34 GMT

Part Number: SN74F38

Hi Team, do we have a specific value for the HBM?

Thank you.

-Mark

SN74LVCH32373A: I need help on reading date code off the IC marking.

Eric Burgos — Tue, 20 Apr 2021 22:03:22 GMT

Part Number: SN74LVCH32373A

I have this P/N SN74LVCH32373AZKER and I need to know how to decode the date code out of the markings on the IC.

Below is what on the IC:

CH373A

02W

A232 G1

Thank you.

LSF0102: Schematic review

Navin Narayanan1 — Tue, 20 Apr 2021 12:09:51 GMT

Part Number: LSF0102
Other Parts Discussed in Thread: SN65DSI83, SN74AUC1G125, TXS0102, LSF0101, LSF0108,

Hi,

This is a follow-on question from this post (link) regarding a level shifter to use for a DSI REFCLK input to the SN65DSI83.

Could you please review schematic below and please let me know if I have connected the level shifter correctly

Thank you very much in advance

Kind regards

Navin

SN74LV1T34: dv/dt Range for SN74LV1T34

Xing He — Tue, 20 Apr 2021 09:23:59 GMT

Part Number: SN74LV1T34
Other Parts Discussed in Thread: SN74AUP1T17

Hi Experts,

My input signal with a low 17V/s slew rate for SN74LV1T34, does it will work normal?

Thanks!

Best Regards,

Xing

SN74LVC3G34: do we have pin to pin solution schmitt trigger support SPI interface

user4979989 — Tue, 20 Apr 2021 08:57:21 GMT

Part Number: SN74LVC3G34
Other Parts Discussed in Thread: SN74LVC3G17

Hi Sir,

Do we have schmitt trigger which is pin to pin compatible with SN74LVC3G34DCTR?

And the schmitt trigger can support SPI interface.

Thank you.

SN74LVC2G07: VIH tolerance

gz wu — Tue, 20 Apr 2021 07:20:20 GMT

Part Number: SN74LVC2G07

Hi All,

Usually, we can only find min VIH in datasheet.

How can I know the tolerance of VIH?

Thanks very much!

TXS02612: Alternate part

Dennis McGlumphy — Mon, 19 Apr 2021 20:31:33 GMT

Part Number: TXS02612
Other Parts Discussed in Thread: TXS0206

Dear Sirs

The TXS01612 is used in a reference design where both voltage translation and multiplexing is required. In My design, (a SD card interface), in need only voltage translation. Please recommend an alterative. Thank you.

SN74LVC1G34: SN74LVC1G34 and SN74LV1T125

LM — Mon, 19 Apr 2021 15:07:18 GMT

Part Number: SN74LVC1G34
Other Parts Discussed in Thread: SN74LV1T125, SN74AHC1G125

Hi there,

I would like to use the SN74LVC1G34 between 2 devices which communicate via UART (3.3V).

The devices will be separated by a long cable of 5 - 10 m and the max speed is 115200 bps.

My concern is the fast edges of this device. Does the device generate fast edges even for a low current drive?

Do you advise this device for this application?

How can I reduce the slew rate? Should I add a capacitor to the output or/and a ferrite?

Is the part SN74LV1T125 more suitable since the driving capability is just 8 mA which helps to reduce line reflections, overshoot and undershoot?

Kind regards,

Laura

SN74AUP1T34: TINA-TI model

Shubha Rai — Mon, 19 Apr 2021 08:52:27 GMT

Part Number: SN74AUP1T34
Other Parts Discussed in Thread: TINA-TI

I am planning to use this part in one of the designs where we need to drive clock for six devices with 1.8V level(19 MHZ). There is only a IBIS model available in the product page. Is there anyway to get a TINA-TI model for this part?

SN74LVT16245B: HU07 GrassValley Part GC114-00018-01 alternative part suggestion

Li Chen92 — Mon, 19 Apr 2021 08:46:42 GMT

Part Number: SN74LVT16245B

Hi TI expert

As i have been received info that this MPN#SN74LVT16245BZRDR have already obsolete , kindly advise if have any other alternative MPN to support for this part to order in future?

Best regards,

Thomas

TXB0102: bi-directional level shift for MDIO / SMI

[FAE] Andrew Wang — Mon, 19 Apr 2021 02:47:14 GMT

Part Number: TXB0102
Other Parts Discussed in Thread: TXS0102, LSF0102

Hi Team,

As title, customer needs 2 channel bi-directional level shift for MDIO / SMI, and wants to double check if TXB0102 or TXB0102 is more fit, any suggestion?

Thanks!

Andrew

Best Device for Inrush Current?

bkmtech — Sat, 17 Apr 2021 04:50:28 GMT

Greetings

Very simply, I have a 12V solenoid that can operate effectively at 250 ma but can draw much more than that?

How do I effectively achieve a current plateau of 250 ma.

The circuit pulses at most for .025 seconds, repeating at most every 2 seconds.

The polarity switches every pulse but one side of the solenoid will disconnect after every pulse.

What is the best "type" of device for this application?

SN55462: Datasheet Parameters

Michael David — Fri, 16 Apr 2021 19:45:11 GMT

Part Number: SN55462

Hello,

I need some help figuring out some parameters that I was not able to determine.

1. What is the output sink and source resistance?

2. Is this just a low side driver?

3. What is the steady state and pk output current?

4. What is the propagation delay?