Editing Emitter-coupled logic (section)

===PECL===
{| class="wikitable" style="float:right; margin-left: 1em;
|+Logic levels for Motorolla ECL/PEC comparison<ref>{{cite web |last=Holland |first=Nick |date=December 2002 |title=Interfacing Between LVPECL, VML, CML and LVDS Levels |url=http://focus.ti.com/lit/an/slla120/slla120.pdf |work=Application Report |publisher=Texas Instruments |id=SLLA120}}</ref>{{r|TND309|p=5}}{{anchor|logic_levels_comparison}}
! Type
! V<sub>ee</sub>
! {{Abbr|V<sub>low</sub>|Logic level LOW (0)}}
! {{Abbr|V<sub>high</sub>|Logic level HIGH (1)}}
!{{Abbr|V<sub>swing</sub>|Logic level swing - difference between V_high and V_low}}
! V<sub>cc</sub>
!{{Abbr|V<sub>cm</sub>|cm - common mode voltage range.}}
|-
!ECL
|–5.2 V
|–1.75 V
|–0.9 V
|–0.85 V
|GND
|
|-
! PECL
| GND
| 3.4 V
| 4.2 V
|0.8 V
| 5.0 V
|
|-
! LVPECL
| GND
| 1.6 V
| 2.4 V
|0.8 V
| 3.3 V
| 2.0 V
|}

'''Positive emitter-coupled logic''', also called '''pseudo-ECL''', (PECL) is a further development of ECL using a positive 5&nbsp;V supply instead of a negative 5.2&nbsp;V supply.<ref>{{cite web |work=EE Times |first=John |last=Goldie |url=http://www.eetimes.com/document.asp?doc_id=1225744 |title=LVDS, CML, ECL – differential interfaces with odd voltages |date=January 21, 2003}}</ref>  Low-voltage positive emitter-coupled logic (LVPECL) is a power-optimized version of PECL, using a positive 3.3&nbsp;V instead of 5&nbsp;V supply. PECL and LVPECL are differential-signaling systems and are mainly used in high-speed and clock-distribution circuits.

A common misconception is that PECL devices are slightly different from ECL devices.
In fact, every ECL device is also a PECL device.<ref>
{{cite web |first1=Cleon |last1=Petty |first2=Todd |last2=Pearson
|url=https://www.onsemi.com/pub/Collateral/AN1406-D.PDF |title=Designing with PECL (ECL at +5.0 V) |id=AN1406-D
|page=3}}
</ref>