AMC3330 datasheet(21/36 Pages) TI

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7.3.4 Isolated DC/DC Converter

The AMC3330 offers a fully integrated isolated DC/DC converter that includes the following components

illustrated in the Functional Block Diagram:

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

the DC/DC converter

• Low-side full-bridge inverter and drivers

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

• High-side full-bridge rectifier

• High-side 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 synchronous to the operation of the ΔΣ modulator to

minimize 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 AMC3330 and can

source up to 1 mA of additional current (IH) for an optional auxiliary circuit such as an active filter, pre-amplifier,

or comparator.

7.3.5 Diagnostic Output and Fail-Safe Behavior

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. 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). 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 VDCDCUV and VHLDOUV as sepecified in the Electrical

Characteristics table. 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 pull-up supply

through a resistor or leave open if not used.

7.4 Device Functional Modes

The AMC3330 is operational when the power supply VDD is applied, as specified in the Recommended

Operating Conditions table.

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AMC3330

SBASA34A – JUNE 2020 – REVISED OCTOBER 2020

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AMC3330 Datasheet(PDF) 21 Page - Texas Instruments