When a digital output pin is at logic LOW and absorbs current from an external load into the device, this LOW-state output current is commonly called the ________ current.

Introduction / Context:
Correctly naming current directions at digital outputs is essential for interpreting datasheets and ensuring loads are driven within ratings. Outputs can source or sink current depending on their logic state and topology.

Given Data / Assumptions:

• Output is in the LOW state.
• Current flows from the load into the output pin and then to ground.
• We are using standard digital terminology.

Concept / Approach:
“Sink current” refers to current flowing into the output (the device “sinks” it) when the pin is LOW. TTL traditionally provides strong sink capability (I_OL) and more limited source capability (I_OH). Datasheets specify maximum sink current along with the guaranteed V_OL level.

Step-by-Step Solution:
Identify current direction: into the output at LOW.Match to terminology: sink current.Confirm with datasheet symbols: I_OL (output low current) corresponds to sinking.

Verification / Alternative check:
Vendor I/O specs list I_OL and the corresponding maximum V_OL to guarantee a valid logic LOW under load.

Why Other Options Are Wrong:
“Ground current” and “return current” are vague and not the formal term for this rating. “Exit current” is nonstandard. “Fan-out” counts loads and is unrelated to current naming.

Common Pitfalls:
Swapping source and sink definitions; remember that at LOW, the pin usually sinks current.

Final Answer:
sink current