13本习题6

6-1. Judge the type of each single-stage amplifier shown in Figure 6.1, and calculate the

small-signal gain of each circuit, assuming γ=0.

out

V in

V

b

out

V b V

out

(a)(b)

(c)

V

Figure 6.1

6-2. Consider the circuit of Figure 6.2 with (W/L)1=20/0.5, I1=1mA, and I S =0.75mA. Assuming

V DD =3V , and λ=0, calculate the ratio of (W/L)2 that places M1 at the edge of the triode region .What is the small-signal gain under this condition? The device parameters are given in

Tab. 6.1.

DD

V in

S

Figure 6.2

6-3. Assume that W/L ratios of Figure 6.3 are (W/L)1 = 2μm/1μm and (W/L)2 = (W/L)3 = (W/L)4

=1μm/1μm. Find the dc value of v IN that will give a dc current in M1 of 110μA. Calculate the small signal voltage gain and output resistance using the parameters of Table 6.2. Assume λ=γ=0.

V 100μA

Figure 6.3

6-4. Calculate the differential transconductance g md and the differential voltage gain A v

of an

n-channel input differential amplifier shown in Figure 6.4 , with the parameters shown in table 6.2. Consider I ss =100μA , and W 1/L 1=W 2/L 2=W 3/L 3=W 4/L 4=1. Assuming all the channel lengths are equal to 1μm, and V DD =5V. If W 1/L 1=W 2/L 2=10W 3/L 3=10W 4/L 4=10, repeat the calculation

V G2

Fig 5.1

Figure 6.4

6-5. Calculate the maximum(V IC (max)) and the minimum input common-mode voltages

(V IC (min)), and the input common mode voltage range (ICMR) of an n-channel input differential amplifier shown in Figure 6.4, with the parameters shown in table 6.2. Assume all MOSFETs are in saturation, all the (W/L)s are equal to 10μm/1μm, I SS =10μA, and V DD =5V .

6-6. Find the value of the unloaded differential-transconductance, g md , and the unloaded

differential-voltage gain, A v , for the p-channel input differential amplifier of Figure 6.5 when I SS =10μA and I SS =1μA . What is the slew rate of the differential amplifier if a 100 pF capacitor is attached to the output? Assuming W1/L1=W2/L2=W3/L3=W4/L4=1, and all the channel lengths are equal to 1μm. Use the transistor parameters of Table 6.2.

V G2

Figure 6.5

6-7. The circuit shown in Figure 6.6 called a folded-current mirror differential amplifier and is

useful for low values of power supply. Assume that all W/L values of each transistor is 100. Using the parameters shown in table 6.2,

a) Find the maximum input common mode voltage, V IC (max) and the minimum input common mode voltage, V

IC (min). Keep all transistors in saturation for this problem. b) What is the input common mode voltage range, ICMR? c) Find the small signal voltage gain, v out /v in , if v in = v 1 - v 2.

Figure 6.6

Table 6.1

NMOS模型

LEVEL=1 VTO=0.7 GAMMA=0.45 PHI=0.9

PSUB=9e+14 LD=0.08e-6 UO=350 LAMBDA=0.1

TOX=9e-9 PB=0.9 CJ=0.56e-3 CJSW=0.35e-11

MJ=0.45 MJSW=0.2 CGDO=0.4e-9 JS=1.0e-8

PMOS模型

LEVEL=1 VTO=-0.8 GAMMA=0.4 PHI=0.8

PSUB=5e+14 LD=0.09e-6 UO=100 LAMBDA=0.2

TOX=9e-9 PB=0.9 CJ=0.94e-3 CJSW=0.32e-11

MJ=0.5 MJSW=0.3 CGDO=0.3e-9 JS=0.5e-8

上表给出的是0.5μm工艺level 1 MOS SPICE 模型参数的典型值，其中的参数定义如下：VTO: VSB=0时的阈值电压（单位：V）GAMMA: 体效应系数（单位：V1/2）PHI: 2ФF（单位：V）TOX: 栅氧厚度（单位：m）NSUB: 衬底掺杂浓度（单位：cm-3）LD: 源/漏侧扩散长度（单位：m）UO: 沟道迁移率（单位：cm2/(v/s)）LAMBDA: 沟道长度调制系数（单位：V-1）CJ: 单位面积的源/漏结电容（单位：F/m2）CJSW: 单位长度的源/漏侧壁结电容（单位：F/m）PB: 源/漏结内建电势（单位：V）

MJ: CJ公式中的幂指数（无单位）MJSW: CJSW等式中的幂指数（无单位）CGDO: 单位宽度的栅/漏交叠电容（单位：F/m）CGSO: 单位宽度的栅/源交叠电容（单位：F/m）JS: 源/漏结单位面积的漏电流（单位：A/m2）

Table 6.2