AMC1351EVM: AMC1351 has gain error 1.7%

Swatej Chauhan

Part Number: AMC1351EVM
Other Parts Discussed in Thread: AMC1351

Tool/software:

Hi,

I am using AMC1351. I am using a power supply from 0-30Vdc and using a voltage divider in my scaling it down to 0-5Vdc. While calculating gain error its always 1.4-1.8%. i am not sure how to correct it.
VDD1 is 5Vdc, Vdd2 is 3.3Vdc, input voltage is 0-5VDc. I am collecting value of output using Data logger DAQ970A. Please help.

5 months ago

0 Swatej Chauhan 5 months ago

Prodigy 10 points

this is wiring diagram

0 Saleh Ahmad 5 months ago in reply to Swatej Chauhan

TI__Expert 5950 points

Hi Swatej,

Can you provide some details into your application?

Do you have measurement data you can share?

Have you measured at the inputs and outputs of the device to determine where the gain error is occurring?

Thanks.

0 Swatej Chauhan 5 months ago in reply to Saleh Ahmad

Prodigy 10 points

I am just trying to measure the voltage and see the accuracy of AMC1351.
I have measured input and output of the device and then compared actual and measured gain to determine the error.

Please see the data below.

Do you think its something related to VDD1 and VDD2 power supplied. I am using EC Buying 3PCS Mini Step Down Power Supply Intelligent Home Switch DC Power Module AC DC Voltage Regulator 220V to 5V 5W AC DC Converter HLK-5M05 : Amazon.ca: Electronics

Input Supply Voltage from Power Supply	Input Divider Voltage to AMC	Expected Output Voltage	Output Voltage from AMC measured	Error of Output %
10.0424325	1.65407303	0.661629212	0.672834425	1.6936%
12.0661002	1.98493205	0.79397282	0.808264621	1.8000%
14.0881319	2.31733779	0.926935116	0.943601582	1.7980%
16.0469568	2.63917736	1.055670944	1.07469356	1.8019%
18.0772607	2.97256177	1.189024708	1.21055108	1.8104%
20.0203307	3.29155303	1.316621212	1.34061246	1.8222%

0 Saleh Ahmad 5 months ago in reply to Swatej Chauhan

TI__Expert 5950 points

Hi Swatej,

Are the 'Input Divider Voltage to AMC' measurements calculated based on the resistor divider or actually measured with a scope or dmm?

One way to account for any gain and offset errors would be through the software.

Thanks.

0 Swatej Chauhan 5 months ago in reply to Saleh Ahmad

Prodigy 10 points

except for "Expected Output Voltage" all the other values are measured using DAQ Module.
I used a power supply directly to provide the 0-5V and then error drops down to 0.06% which is amazing, can you tell me what i need to do different with voltage divider because this 1.7% error occurs because of voltage divider.

0 Saleh Ahmad 5 months ago in reply to Swatej Chauhan

TI__Expert 5950 points

Hi Swatej,

The best way to account for this is to do an offset/gain calibration and account for the error in software.

You could use lower tolerance resistors, but they will be more expensive and still have some additional error.

Thanks.

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AMC1351EVM: AMC1351 has gain error 1.7%