The ac schematic of a wideband MOS current amplifier is shown in Fig. 7.45. The W/L of M₂is four times that of M₁and corresponding bias currents are I_D1= 1 mA and I_D2= 4 mA. Calculate the low-frequency, small-signal current gain i_o/i_iand use the zero-value time-constant method to estimate the ˆ’3-dB frequency. Calculate the 10 to 90 percent rise time for a small step input. Data at the operating point: M₁: C_gd= 0.05 pF, C_gs= 0.2 pF, C_sb= C_db= 0.09 pF, V_ov= 0.3 V, and r_o= ˆž. M₂: C_gd= 0.2 pF, C_gs= 0.8 pF, C_sb= C_db= 0.36 pF, V_ov= 0.3 V, and r_o= ˆž.

Fig. 7.45:

Transcribed Image Text:

M2 M1