In Fig. 6.31b, resistive loads were used to extend the common-mode input range to include V EE . Fig. 6.62 shows another circuit with this

In Fig. 6.31b, resistive loads were used to extend the common-mode input range to include ˆ’V_EE. Fig. 6.62 shows another circuit with this characteristic. Find the common-mode range of this circuit. Assume that V_BE(on)= 0.7 V and V_CE(sat)= 0.1 V for the npn transistors. Also, assume that V_BE(on)= ˆ’ 0.7 V and V_CE(sat)= ˆ’0.1 V for the pnp transistors. Ignore base currents for simplicity.

Fig. 6.31 b:

Fig. 6.62:

Vcc Bias, Qs IBIAS Q2 Q1 Vod VR2 R2 R1 VR1 -VEE = 0 Vcc Bias, Qs Q9 Q2 -o+ Q3 Q4 Q7 -VEE = 0