7.3.3 Analog Output

The AMC1301 offers a differential analog output comprised of the OUTP and OUTN pins. For differential input

voltages (VINP – VINN) in the range from –250 mV to 250 mV, the device provides a linear response with a

nominal gain of 8.2. For example, for a differential input voltage of 250 mV, the differential output voltage (VOUTP

– VOUTN) is 2.05 V. At zero input (INP shorted to INN), both pins output the same common-mode output voltage

VCMout, as specified in the Electrical Characteristics table. For absolute differential input voltages greater than

250 mV but less than 320 mV, the differential output voltage continues to increase in magnitude but with reduced

linearity performance. The outputs saturate at a differential output voltage of VCLIPout, as shown in Figure 7-2, if

the differential input voltage exceeds the VClipping value.

Linear input range (VFSR)

Maximum input range before clipping (VClipping)

320 mV

320 mV

250 mV

250 mV

0

VOUTP

VOUTN

Differential Input Voltage (VINP ± VINN)

VCMout

±

±

VCLIPout

VFAILSAFE

Figure 7-2. Output Behavior of the AMC1301

The AMC1301 offers a fail-safe feature that simplifies diagnostics on a system level. Figure 7-2 shows the

fail-safe mode, in which the AMC1301 outputs a negative differential output voltage that does not occur under

normal operating conditions. The fail-safe output is active in two cases:

• When the high-side supply is missing or below the VDD1UV threshold

• When the common-mode input voltage, that is VCM = (VINP + VINN) / 2, exceeds the common-mode

overvoltage detection level VCMov

Use the maximum VFAILSAFE voltage specified in the Electrical Characteristics table as a reference value for

fail-safe detection on a system level.

7.4 Device Functional Modes

The AMC1301 assumes normal operation as soon as VDD1, VDD2, and the input common-mode voltage (VCM)

are within the operational ranges, as specified in Electrical Characteristics table. In this mode, the output voltage

is proportional to the input voltage.

The AMC1301 enters fail-safe mode whenever the high-side supply (VDD1) is missing or the input common-

mode voltage (VCM) exceeds the specified input-overvoltage detection level VCMov. In this mode, the differential

output voltage is a fixed, negative value (VFAILSAFE). See the Analog Output section for details.

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AMC1301

SBAS667G – APRIL 2016 – REVISED APRIL 2023

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