Positive emitter-coupled logic

In the field of digital technology, the term "positive emitter-coupled logic" means a signal standard for representing a binary signal as a logic level. The designation is derived from the designation emitter-coupled logic (ECL) and comes in contrast to ECL with only one positive supply voltage.

Due to the high switching speeds which can be achieved with PECL, it is primarily used to transmit a clock signal. Like LVDS, PECL is a differential signaling, which is why a pair of conductors (referred to as _n and _p) is required for transmission. The two logic states are encoded by the sign of the potential difference. Correspondingly, the current direction changes through the termination required at the line end. While PECL is used for 5 V systems, LVPECL (low-voltage PECL) is developed for 3.3 V developed circuit families.

The logic levels for PECL and LVPECL are summarized in the following table. Weblinks Edit sourcetext Single-level Edit source text

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