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THS7372: Typical application questions

February 15, 2019, 4:19 am
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Part Number:THS7372

Hi Team,

Please kindly help on below questions. Thanks

1. Data sheet Figure84 has pull low resistor 37.4ohm on buffer input termination, but EVM show 75ohm. What value should we follow? (We already control the RGB trace impedance are 75ohm).

2. Data sheet Figure84 has series 75ohm on output termination. Do we still need these resistors if we already control the RGB trace 75ohm impedance?

3. We add a Pi-filter, is the sch OK? The pull down resistors should be 75ohm or 150ohm?

Thanks

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XTR111: XTR111

February 15, 2019, 7:11 am
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Part Number:XTR111

When using the XTR111 to get a 0-3V output (schematic in Figure 48 of the datasheet), I get an oscillation at the output of about 100mV at 250kHz at the top of the useful signal.

Any idea to avoid that?

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LMV341: Regarding input voltage

February 15, 2019, 10:01 am
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Part Number:LMV341

Hi Team,

Customer changed from LMV 342 to LMV 341.

The input terminal (+) potential was 200 mV and the input terminal (-) was 150 mV.

In the case of LMV 342, the input terminal (-) was also 200 mV.

I would like to know the cause.

(Please visit the site to view this file)

Best Regards,

Kenji

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LM321LV: LM321LV

February 15, 2019, 8:12 pm
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Part Number:LM321LV

Hi


Can you please help to address below queries from my customer?

We are using an LM321LVIDBVR and our parts are marked as 1SPF and they are in the SOT-23-5 package.  According to the TI datasheet the pinout for the DBV package is shown on the left side of the attached scan.  The datasheet is SBOS944A revised Jan 2019.  Our board PCB footprint was designed for that footprint.  However, the parts we have received are actually pinned out like the DCK SC-70 package shown on the right side of the datasheet, even though they are in the SOT-23-5 package.  We discovered this because our simple differential amp circuit did not work.  Once I reworked the pinout for the SC-70 package into our board the diff amp worked fine.

 

So, what has happened here?  Am I missing something?  We have the SOT-23-5 package but it is bonded out like the SC-70.  Can you please help us understand if the datasheet is wrong or the bonding is in error?

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OPA552: Can I make 0V amplified output when feeding 0 V input?

February 15, 2019, 9:12 pm
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Part Number:OPA552

Hi, guys. I'm using Arduino DUE's DAC and a high pass filter to create the above pulse.

I'm using OPA552PA supplying + - 30 V and the aforementioned pulse is the V_in (positive input).

R1 = 150k, R2 = 10k Ohm

When my input signal becomes 0V, I want the output voltage to become 0 V as well.

What type of extra circuit should I add to make this feasible?

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XTR117: We require two 4-20mA outputs at a time, how it is possible?

February 15, 2019, 9:17 pm
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Part Number:XTR117

With XTR117 IC, we tried for two outputs, but due to command return path, current mismatching occurred .

At each output channel we should get proper & accurate current .

What will be the solution over this ?

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LM301A: Test circuit for testing OP AMP

February 15, 2019, 11:47 am
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Part Number:LM301A

Is there a simple generic test circuit that TI uses to test if OP-AMP LM301AH is functioning properly ? 

Thanks

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INA226: Output current reporting issue

February 15, 2019, 10:18 pm
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Part Number:INA226

Hi,

We are encountering an intermittent issue with an INA where it just keep reporting zero on the current although there is current through the shunt resistor, it reports the output voltage correctly.We have monitored the I2C waveforms to confirm that we have send the right command to read the output current and the output voltage.

The issue is intermittent,  sometime it is good upon start-up and sometimes it is bad.   Are there any conditions where the INA226 will stop/latch the output current reporting but will maintain the output voltage reporting?  Is there any power sequencing on the Vcc, SDA, SCL, and Alert that could trigger this condition?

Regards,

Oliver

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LM258: LM258 To be 20mA output

February 17, 2019, 6:31 am
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HI Sir

I use the LM258 to be a 4-20mA Output, I find the output current from 20mA down to 19.985mA, it's out of spec,

do you have any suggestion? thanks

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ONET8501PB: Questions for ONET8501PB Application

February 18, 2019, 12:36 am
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Part Number:ONET8501PB

Hi Experts,

Our customer wants to use ONET8501PB connected to ROSA with reversed differential input due to some layout optimizing issues, can you help to check is it OK for such using?

ROSA D- output connected to ONET8501PB DIN+

ROSA D+ output connected to ONET8501PB DIN-

Thanks a lot!

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TINA/Spice/OPA188: OPA188 OPAmp TINA model

February 18, 2019, 12:37 am
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Part Number:OPA188

Tool/software:TINA-TI or Spice Models

OPA188 website's link is dead. I wanna use TINA model to simulate circuit.

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OPA2677: any high output current high speed opamp could drive 5 ohms loads

February 18, 2019, 12:50 am
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Part Number:OPA2677

Hi team,

I am looking for a high output current amplifier for my mobile phone customer. They are requiring the amp:

1. Output 300mA current on 5 ohms load;

2. The bandwidth need to be over 100mA;

3. The package need to be BGA or QFN, small enough to fit in the phone.

4. Power supply better to be  <5V, lower is better.

They said they could accept the two channels paralleled solution, but not accept to add a big in serial resistor. Since the swing. Could you suggest?

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Cross Reference Type (Q: Same Functionality & Pinout)

February 18, 2019, 2:11 am
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I have a question about cross reference solution:

This Analog PN “AMP03GS-REEL” has cross part INA105KU/2K5 with code (Q: Same Functionality & Pinout) and according to the description of Q type it is not exact equivalent, I compared many of the electrical characteristics between the two parts and found they are similar, could you please clarify what are the used factors/parameters that are different between the both parts and you depend on to determine the cross type as Q (not exact equivalent).

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INA333: Output oscillating at around 1Hz in my circuit

February 18, 2019, 2:12 am
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Part Number:INA333

Hi,

I am using the circuit shown below. The problem that I have is it is unstable. With no input signal it begins to oscillate at the output of the IA at around 1Hz, Do you have any idea why it would do this?

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INA105: Cross Reference (Q Type)

February 18, 2019, 2:31 am
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Part Number:INA105

I have a question about cross reference solution:

This Analog PN “AMP03GS-REEL” has cross part INA105KU/2K5 with code (Q: Same Functionality & Pinout) and according to the description of Q type it is not exact equivalent, I compared many of the electrical characteristics between the two parts and found they are similar, could you please clarify what are the used factors/parameters that are different between the both parts and you depend on to determine the cross type as Q (not exact equivalent).

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LMV342: LMV342

February 18, 2019, 2:31 am
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Part Number:LMV342

Hi,

I am designing a precision rectifier circuit for one of my design. Here the input is from current sense transformer and this using differential amplifier it will be converted to single ended. 

I am using an precision rectifier to convert that AC to dc. Please find the attached circuit. The part used is LMV342IDGKR. I have see that " Input voltage (either input) –0.3     5.5 V  " in the datasheet. Can you tell me the attached circuit will work without any issue.(Simulation is working fine)

If not can you suggest a part which suits for rectifier application with the package of  "2 Circuit Rail-to-Rail 8-VSSOP"

Regards

Anuraj NK

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OPA27: Allowable max junction temperature

February 18, 2019, 6:58 am
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Part Number:OPA27

What is the absolute max allowable junction temperature of OPA27GU?

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INA226EVM: Accuracy of INA226

February 18, 2019, 7:33 am
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Part Number:INA226EVM

Hello,

I'm contacting you about the INA226EVM KIT and the INA226EVM software.

In mode "shunt and bus continuous" (and others) We cannot read accurate current values (+/- 10%) when we vary the POWER SUPPLY voltage on a fixed load resistor (12ohms). Our shunt resistance is 80mohms (mounting "High - Side Shunt"). We take a calibration register for a current of 1A maximum. We calculated a register value at 2097 with the formulas given in the datasheets. Can you explain where the problem may come from?

Thanks.

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INA219: Bus voltage offset - not a constant value?

February 18, 2019, 7:43 am
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Part Number:INA219

I am developing an application that uses the INA219B and noticed the bus voltage offset mentioned in other threads already. I am not using a filter, the shunt is 0.1 Ohm and I connected a DMM to Vin- to directly compare with the INA219 reading. BRNG = 1 (32V), no load applied.

I read in a thread that the INA219 bus  voltage offset is (more or less) constant and could be corrected. In my measurements, the offset is not constant but it seems to follow a linear function and, with regression analysis, a correction function can be applied (as in the last three columns).  My question: is the bus offset supposed to be constant or is the observed behaviour correct?

Thanks.

Slope-0.001005742100229
Intercept0.028764918466064
DMM Vin-INA219DiffErr%CorrectedCorr. DiffCorr Err%
1.00460.9760.02862.85%1.003754549952170.0008454500478260.08%
2.00271.9760.02671.33%2.00275071876194-5.07187619360749E-050.00%
3.00382.980.02380.79%3.0057438703454-0.001943870345397-0.06%
4.00153.9760.02550.64%4.0007404414520.0007595585480020.02%
5.00344.980.02340.47%5.00373278844178-0.000332788441779-0.01%
6.00515.980.0250999999999990.42%6.002725336579980.002374663420020.04%
7.00776.9880.01970.28%7.00971697955029-0.00201697955029-0.03%
8.00767.9880.0196000000000010.24%8.00871133802427-0.001111338024272-0.01%
9.00428.9840.0202000000000010.22%9.003709015447180.0004909845528170.01%
10.00329.9840.01920.19%10.00270427908910.0004957209109440.00%
11.000910.9840.01690.15%11.0017008501957-0.000800850195658-0.01%
12.005211.9880.0172000000000010.14%12.00469078340440.0005092165956030.00%
13.009712.9920.01770.14%13.00768051546470.0020194845352820.02%
14.001313.9880.0133000000000010.09%14.0026832215981-0.001383221598129-0.01%
15.002914.9880.0149000000000010.10%15.00167587031050.001224129689460.01%
16.003915.9920.0119000000000010.07%16.0046691224682-0.000769122468210.00%
17.003116.9920.0110999999999990.07%17.0036641849617-0.0005641849616640.00%
18.007917.9960.0119000000000010.07%18.00665361529930.001246384700650.01%
19.0098190.0097999999999980.05%19.00964596228910.0001540377108680.00%
20.003519.9960.00750.04%20.0046465563641-0.001146556364134-0.01%

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INA219: Are bus voltage and shunt voltage LSBs achieved by oversampling and averaging

February 18, 2019, 2:04 pm
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Part Number:INA219

I am somewhat confused about the resolution (LSB) of bus voltage and shunt voltage. For example the bus voltage LSB is 4 mV (data sheet) but a 12-bit ADC measuring a 32V should have 7.8 mV LSB. The same applies to the shunt voltage with a data sheet resolution of 10 uV, but  +/-40 mV measured by a 12 bit ADC gives a LSB of 19.5 uV? 

I am aware that oversampling with averaging of the readings can increase the resolution of an ADC (if there is uncorrelated noise in the signal). The data sheet states that a 12-bit conversion takes 532 uS, On the other hand the filter section of the data sheet states that the ADC is running at typically 500 Khz  (2 uS) sampling rate. Such a high sampling rate would allow plenty of averaging to take place to get the extra resolution beyond the 12-bit even if  SADC and BADC in the configuration register are left at the default of 1 sample.  Is this what you are doing? Or are you expecting the user to set BADC and SADC to be set to at least 4 samples to boost the resolution to "13-bit" ?

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