8.2.1 Design Requirements

Table 8-1 lists the parameters for this typical application.

Table 8-1. Design Requirements

PARAMETER

VALUE

Supply voltage

3.3 V or 5 V

±250 mV (maximum)

8.2.2 Detailed Design Procedure

The AMC3301-Q1 requires a single 3.3-V or 5-V supply on its low-side. The high-side supply is internally

generated by an integrated DC/DC converter as explained in Section 7.3.4.

The ground reference (HGND) is derived from the terminal of the shunt resistor that is connected to the negative

input of the AMC3301-Q1 (INN). If a four-pin shunt is used, the inputs of the AMC3301-Q1 are connected to the

inner leads and HGND is connected to one of the outer shunt leads. To minimize offset and improve accuracy,

set the ground connection to a separate trace that connects directly to the shunt resistor rather than shorting

HGND to INN directly at the input to the device. See Section 10 for more details.

8.2.2.1 Shunt Resistor Sizing

• The voltage drop caused by the nominal current range must not exceed the recommended differential input

• The voltage drop caused by the maximum allowed overcurrent must not exceed the input voltage that causes

8.2.3 Input Filter Design

TI recommends placing an RC filter in front of the isolated amplifier to improve signal-to-noise performance of

the signal path. Design the input filter such that:

• The cutoff frequency of the filter is at least one order of magnitude lower than the sampling frequency (20

MHz) of the ΔΣ modulator

• The input bias current does not generate significant voltage drop across the DC impedance of the input filter

• The impedances measured from the analog inputs are equal

For most applications the structure shown in Figure 8-2 achieves excellent performance.

10 Ÿ

10 Ÿ

8.2 nF

INP

INN

AMC3301-Q1

HGND

Figure 8-2. Differential Input Filter

AMC3301-Q1

SBASA73 – JULY 2020

www.ti.com

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