Help Understanding Glucose Meter Schematic in AN4364

[Nikunj_Solanki]

Dear NXP Team,

I am working on a glucose meter and referring to Document AN4364. However, I am having trouble understanding the schematic, especially the following part:

"The output generated by the test strip is a current that represents the glucose concentration. This current must be converted to voltage so that it can be properly filtered and treated. This conversion is performed using a current-to-voltage converter that has a single supply, low-input offset voltage, low-input offset and bias current TRIAMP embedded on the K53, and an external feedback resistance."

I understand that the K53 MCU has a built-in TRIAMP, but I need to use an external glucose meter amplifier circuit. Could you please provide a reference design or guidance on how to implement this?

Thank you for your support!

Best regards,
Nikunj

[Pablo_Ramos]

Hi @Nikunj_Solanki 

You can take as reference the circuit shown in the section 3.1.4 Amplification and filtered of the AN4364.

The amplifier (green) uses the following equation.

The filter (red) uses the following equation.

You can find more information regarding operational amplifiers in the following link:
Operational Amplifier (OPAMP) Usage on

[Nikunj_Solanki]

Hi, I would like to confirm whether the amplifier is built into the K53 or if an external amplifier is required. If an external amplifier is used, could you please recommend the appropriate part number?

Best regards

[Pablo_Ramos]

Hi @Nikunj_Solanki,

The amplification section is built into the K53.

The TRIAMP0 output is driven to external pin, TRI0_OUT, and is shared with the OP1_DM2 analog input.

See section 3.7.5.1 TRIAMP signals of K53 Sub-Family Reference Manual

Also, I recommend you checking the following links for more information regarding glucose meters.

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