Emitter-coupled Logic
INEL4207 - Spring 2011
Figure 15.25 The basic element of ECL is the differential pair. Here, VR is a reference voltage.
Find VR if vD1 = vD2
= vBE = 0.75V.
Neglect iB.
Figure E15.12
Figure 15.26 Basic circuit of the ECL 10K logic-gate family.
For previous circuit, find IE through RE if A and
B are left open.Also find vC,QR and vCA,B. Use VR
= -1.32V, VBE=0.75V and a very large β.
Figure 15.27 The proper way to connect high-speed logic gates such as ECL. Properly terminating the transmission line connecting the two
gates eliminates the “ringing” that would otherwise corrupt the logic signals. (See Section 15.4.6.)
Figure 15.28 Simplified version of the ECL gate for the purpose of finding transfer characteristics.
Find VOL (negecting iC)
and VOH if β=100. Then
find NMH and NML if VIL
and VIH are defined as the
conditions for which
IE, QR/IE, QA = 99 and
viceversa.
Figure 15.30 Circuit for determining VOH.
Figure 15.31
15.28
Figure 15.32
δ = -2mV/℃
Figure 15.33 Equivalent circuit for determining the temperature coefficient of the reference voltage VR.
∆VOL = -0.43 δ
Figure 15.34 Equivalent circuit for determining the temperature coefficient of VOL
∆VOH = -0.93 δ
Figure 15.35 Equivalent circuit for determining the temperature coefficient of VOH.
Figure 15.36 The wired-OR capability of ECL.