Shown in Fig. P5.25 is a voltage comparator that allows for VOL and VOH to be set independently of the supplies VCC and VEE. The circuit consists of the differential pair Q1-Q2, the current mirrors...

Shown in Fig. P5.25 is a voltage comparator that allows for VOL and VOH to be set independently of the supplies VCC and VEE. The circuit consists of the differential pair Q1-Q2, the current mirrors Q3-Q4, Q5-Q6, and Q7-Q8, the open-collector output stage Q9, and the external pull-up resistor RPU.

(a) Let VCC 5 2VEE 5 10 V, IEE 5 0.2 mA, VH 5 5 V, VL 5 0 V, F9 5 200, VCE9(sat) 5 0.2 V, and RPU 5 10 kV. Assuming ro @ r for simplicity, fi nd VOH, VOL, and the gain a for vO 5 1 ⁄2(VOL 1 VOH). Hence, estimate the difference VIH 2 VIL. (b) If vN 5 0, fi nd vP for vO 5 1 ⁄2(VOL 1 VOH).