CLKIN

DOUT

VIN ” ±320 mV (AMC1306x05: ±64 mV)

DOUT

VIN • 320 mV (AMC1306x05: 64 mV)

...

...

...

...

...

...

127 CLKIN Cycles

127 CLKIN Cycles

VCM

CLKIN

AVDD GOOD

Missing AVDD

DOUT

VCM • 9CMov

1

AVDD

VCM < VCMov

Valid Bit Stream

AVDD GOOD

VCM < VCMov

0

1

Valid Bit Stream

...

Test Pattern

tISTART

tASTART

Bit Stream Not Valid

26

AMC1306E05, AMC1306E25, AMC1306M05, AMC1306M25

SBAS734C – MARCH 2017 – REVISED JANAURY 2020

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Product Folder Links: AMC1306E05 AMC1306E25 AMC1306M05 AMC1306M25

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8.4 Device Functional Modes

8.4.1 Fail-Safe Output

In the case of a missing high-side supply voltage AVDD, the output of a ΔΣ modulator is not defined and can

cause a system malfunction. In systems with high safety requirements, this behavior is not acceptable.

Therefore, the AMC1306 implements a fail-safe output function that ensures that the output DOUT of the device

offers a steady-state bitstream of logic 0's in case of a missing AVDD, as shown in Figure 53.

Additionally, if the common-mode voltage of the input reaches or exceeds the specified common-mode

overvoltage detection level VCMov as defined in the Electrical Characteristics table, the AMC1306 offers a steady-

state bitstream of logic 1's at the output DOUT, as also shown in Figure 53.

Figure 53. Fail-Safe Output of the AMC1306

8.4.2 Output Behavior in Case of a Full-Scale Input

If a full-scale input signal is applied to the AMC1306 (that is, VIN ≥ VClipping), the device generates a single one or

zero every 128 bits at DOUT, depending on the actual polarity of the signal being sensed, as shown in Figure 54.

In this way, differentiating between a missing AVDD and a full-scale input signal is possible on the system level.

Figure 54. Overrange Output of the AMC1306