626
6 Reverse Engineering of Microcircuits
Fig. 6.97 (continued)
Fig. 6.97b. The time t i is determined by the time of activation of the horizontal p-n-p
PCS transistor and the switching time of the n-p-n transistor.
Principle difficulties in implementation of the PCS were down to two aspects: (a)
finding the circuitry-based method of PCS power circuit implementation (1
E ); (b)
implementation of the conjunction circuit from the values of supply voltages (&
E ).
Figure 6.97c shows the draft of the structure and the equivalent electrical circuit of
the I
2 L gate with two injectors connected to different power sources. The use of such
I
2 L gates for implementation of all PCS elements helps ensure reliable operation of
the PCS if supply voltage is supplied to at least one power input of the LSIC injectors.