Vdc2

Vdc2 is a designation used in electronic schematics and documentation to label a secondary direct-current (DC) power rail. The term is not standardized across manufacturers; the actual voltage and purpose of Vdc2 are defined by the specific device or circuit in which it appears. In many designs, a first rail is labeled Vdc1 or similar, with Vdc2 representing a different voltage level or a derived supply used by a particular subsystem such as analog circuitry, memory, or peripheral interfaces.

In practice, Vdc2 can carry a wide range of voltages depending on the design requirements. It may be a positive or negative rail, and its voltage could be as common as +3.3 V, +5 V, or others specified by the design. The rail is typically generated by a regulator stage and is accompanied by filtering, decoupling capacitors, and protection components. Proper isolation and layout practices are important to minimize noise coupling between Vdc2 and other rails, especially in mixed-signal or high-speed circuits.

Testing and validation involve measuring the rail with respect to the system ground, both under no-load and typical operating load conditions. It is essential to follow the device’s documentation to confirm the intended voltage, tolerance, and power budget for Vdc2. Any changes to the rail require updating schematics and BOMs to maintain traceability and safety.

See also: Vcc, Vdd, power rail, decoupling, voltage regulator.