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Fig. 13.2 Typical voltage transfer characteristic (VTC) of a logic inverter, illustrating the definition of the critical points.

Fig . 13.3 Definitions of propagation delays and switching times of the logic inverter

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Fig . 13 . 2 Typical voltage transfer characteristic (VTC) of a logic inverter, illustrating the definition of the critical points. Fig . 13.3 Definitions of propagation delays and switching times of the logic inverter. - PowerPoint PPT Presentation

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Page 1: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.2 Typical voltage transfer characteristic (VTC) of a logic inverter, illustrating the definition of the critical points.

Page 2: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.3 Definitions of propagation delays and switching times of the logic inverter.

Page 3: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.4 (a) The CMOS inverter and (b) its representation as a pair of switches operated in a complementary fashion.

Page 4: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.5 The voltage transfer characteristic (VTC) of the CMOS inverter when QN and QP are matched.

Page 5: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.12 A two-input CMOS NOR gate.

Page 6: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.13 A two-input CMOS NAND gate.

Page 7: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.16 Proper transistor sizing for a four-input NOR gate. Note that n and p denote the (W/L) rations of QN and QP, respectively,

of the basic inverter.

Page 8: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.17 Proper transistor sizing for a four-input NAND gate. Note that n and p denote the (W/L) rations of QN and QP, respectively,

of the basic inverter.

Page 9: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.21 VTC for the pseudo-NMOS inverter. This curve is plotted for VDD = 5, Vtn = -Vtp = 1 V, and r = 9.

Page 10: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.33 (a) basic structure of dynamic-MOS logic circuits; (b) waveform of the clock needed to operate the dynamic-logic circuit; and (c) an example circuit.

Page 11: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.34 (a) Charge sharing. (b) Adding a permanently turned-on transistor QL solves the charge-sharing problem at the expense of static-power dissipation.

Page 12: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.35 Two single-input dynamic-logic gates connected in cascade. With the input A high, during the evaluation phase CL2 will

partially discharge and the output at Y2 will fall lower than VDD, which can cause logic malfunction.

Page 13: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.37 (a) Two single-input DOMINO CMOS logic gates connected in cascade. (b) Waveforms during the evaluation phase.

Page 14: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.38 (a) Basic latch. (b) The latch with the feedback loop opened. (c) Determining the operating point of the latch.

Page 15: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.40 CMOS implementation of a clocked SR flip-flop. The clock signal is denoted by .

Page 16: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.42 A simpler CMOS implementation of the clocked SR flip-flop. This circuit is popular as the basic cell in the design of static random-access memory chips.

Page 17: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.44 A simple implementation of the D flip-flop. The circuit in (a) utilizes the two-phase nonoverlapping clock whose waveforms are shown in (b).

Page 18: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.45 (a) A master-slave D flip-flop. Note that the switches can be, and usually are, implemented with CMOS transmission gates. (b) Waveforms of the two-phase nonoverlapping clock required.

Page 19: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.47 Monostable circuit using CMOS NOR gates. Signal source vI supplies the trigger pulses.

Page 20: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.50 Timing diagram for the monostable circuit in Fig. 13.47.

Page 21: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.52 (a) A simple astable multivibrator circuit using CMOS gates. (b) Waveforms for the astable circuit in (a). The diodes at the gate input are assumed ideal and thus limit the voltage vI1 to 0 and VDD.

Page 22: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.53 (a) A ring oscillator formed by connecting three inverters in cascade. (Normally at least five inverters are used.) (b) The resulting waveform. Observe that the circuit oscillates with frequency 1/(6tp).

Page 23: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.54 A 2M+N-bit memory chip organized as an array of 2M rows x 2N columns.

Page 24: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.55 A CMOS SRAM memory cell.

Page 25: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.60 A differential sense amplifier connected to the bit lines of a particular column. This arrangement can be used directly for SRAMs (which can utilize both B and B lines). DRAMs can be turned into differential circuits by using the “dummy cell” arrangement shown in Fig. 13.61.

Page 26: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.61 Waveforms of vB before and after activating the sense amplifier. In a read-1 operation, the sense amplifier causes the

initial small increment V(1) to grow exponentially to VDD. In a read-0 operation, the negative V(0) grows to 0. Complementary

signal waveforms develop on the B line.

Page 27: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.62 Arrangement for obtaining differential operation from the single-ended DRAM cell. Note the dummy cells at the far right and far left.

Page 28: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.63 A NOR address decoder in array form. One out of eight lines (row lines) is selected using a 3-bit address.

Page 29: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.64 A column decoder realized by a combination of a NOR decoder and a pass-transistor multiplexer.

Page 30: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.65 A free column decoder. Note that the colored path shows the transistors that are conducting when A0 = 1, A1 = 0, and A2 =

1, the address that results in connecting B5 to the data line.

Page 31: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.66 A simple MOS ROM organized as 8 words x 4 bits.

Page 32: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.67 (a) Cross section and (b) circuit symbol of the floating-gate transistor used as an EPROM cell.

Page 33: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.68 Illustrating the shift in the iD-vGS characteristic of a floating-gate transistor as a result of programming.

Page 34: Fig .  13.3   Definitions of propagation delays and switching times of the logic inverter

Fig. 13.69 The floating-gate transistor during programming.