64 mV

64 mV

50 mV

50 mV

0

Common mode output voltage

±

±

Clipping output voltage

Figure 7-3. AMC3302 Output Behavior

7.3.4 Isolated DC/DC Converter

The AMC3302 offers a fully integrated isolated DC/DC converter stage that includes following components

illustrated in Section 7.2:

• Low-dropout regulator (LDO) on the primary side to stabilize the supply voltage VDD that drives the primary

side of the converter

• Primary full-bridge inverter and drivers

• Laminate-based, air-core transformer for high immunity to magnetic fields

• Secondary full-bridge rectifier

• Secondary LDO to stabilize the output voltage of the DC/DC converter for high analog performance of the

signal path

The DC/DC converter uses a spread-spectrum clock generation technique to reduce the spectral density of the

electromagnetic radiation. The resonator frequency is synchronized to the operation of the ΔΣ modulator to

minimize the interference with data transmission and support the high analog performance of the device.

The architecture of the DC/DC converter is optimized to drive the high-side circuitry of the AMC3302 and can

7.3.5 Diagnostic Output

The open-drain DIAG pin can be monitored to confirm the device is operational and the output voltage is valid.

During power-up, the DIAG pin is actively held low until the high-side supply is in regulation and the device

operates properly. During normal operation, the DIAG pin is in high-impedance (HiZ) state and is pulled high

through an external pullup resistor. The DIAG pin is actively pulled low if:

• The low-side does not receive data from the high-side (for example, because of a loss of power on the high

side). In this case, the amplifier outputs are driven to negative full scale.

• The high-side DC/DC output voltage (DCDC_OUT) or the high-side LDO output voltage (HLDO_OUT) drop

below their respective undervoltage detection thresholds (brown-out). In this case, the low-side may still

receive data from the high-side but the data may not be valid. The amplifier outputs are driven to negative

full-scale.

During normal operation, the DIAG pin is in a high-impedance state. Connect the DIAG pin to a pullup supply

through a resistor or leave open if not used.

7.4 Device Functional Modes

The AMC3302 is operational when the power supply VDD is applied, as specified in the Recommended

Operating Conditions table in Section 6.

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AMC3302

SBASA11 – AUGUST 2020

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