For the following experiments always tie pin 14 to 5 v and pin 7 to. Dont care logic diagram a1 b1 y1 3 1 2 a2 b2 y2 6 4 5 a3 b3 y3 8 10 a4. 25 v ta operating ambient temperature range 54 74 55 0 25 25 125 70 c ioh output current. Observe that the circuit contains 5 transistors and 3 diodes. It is best to ground the unused negative scope inputs when. 596 A multiple emitter bjt is used to provide the inputs to the gate. Design open collector inverter which must provide ttl logic levels. The following are examples of valid part numbers you might find on a 7400 chip: sn7400n. Dm74ls00 quad 2-input nand gate dm74ls00 quad 2-input nand gate general description this device contains four independent gates each of which performs the logic nand function. The truth table and equivalent gate circuit an inverted-output nor gate are shown here. Based on your analysis of the transistor circuit, determine what type of gate and, or, nand, nor, xor, etc. An advantage of the multiple emitters bjt is that it requires much less chip area than using individual resistors. Size: emitter window of the input multiemitter transistor: 16x16 ?Msq. The below figure shows the circuit diagram for a three input ls-ttl nand gate74ls00.
Also connect the output of the seventh gate to the oscilloscope. Give the truth table for ex-nor and realize using nand gates? 4. Figure 1 shows internal schematic of basic two inputs ttl nand gate. 76 The circuit shown is that of one of the four gates inside a quad two-input nand type70 pages. Method ii: remove the function generator connection and one of the nand gates. Based on your analysis of the transistor circuit, determine what type of gate and, or, nand. As you no doubt recall, any logic expression can be implemented using just nand gates. Notice that this circuit looks similar to those found in analogue push pull amplifiers, except that the transistors here. Diode transistor logic circuits a typical dtl nand gate is shown in figure 3. We know that nand function can be obtained by inverting the output of1 pages. A nand gate with transistor-transistor logic, ttl, 2.
The objective of the lab is to understand important concepts like transition levels, voltage transfer. Matched complementary pairs of mosfet transistors are packaged in the cd4007 chip. 202 When one of the inputs is high, the output is low; otherwise, the output is high. When t2 starts conducting, the stored base charge of t3 dissipates through the t2 collector, driving t3 into cut-off. Studying the internal connection of and, or, nand and nor. To build a basic rs latch structure from ttl ssi gates and use this rs latch to construct a switch debouncer. University of connecticut 60 diode-transistor logic dtl n if all inputs are high, the transistor saturates and v out goes low. !C in fig line can be 1 at any time en a b q1 q2 q3 q4 f 0 0 0 on off off off 2. However, most manufacturers have their owndesignation which includes these numbers, but adds some extra characters. High impedance ttl c ompatible inputs significantly reduce c urrent loadingdatasheet: download 74lvc00a datasheet. Preset binary cntr w/ clear quad d flip-flop 74243. 1 voltage level table for a two-input ttl nand gate. The nand function is obtained by combining a diode. 74lvc00a low-voltage cmos quad 2-input nand gate with 5 v?Tolerant inputs. In addition to offering the standard ls ttl circuits, motorola offers the fast schottky and ttl family. D inputs are ttl-voltage compatible description/ordering information. Unfortunately, we cant very well simulate that on a breadboard socket. 1 shows the internal schematic of a schottky ttl nand gate.
The 7401 two-input nand gate with open collector output. Figure 8 ttl two input nand gate hardware setup: connect your circuit to the adalm2000 i/o connector as indicated by the green boxes. 2 basics of ttl the transistor transistor logic ttl family has heavily dependence on transistors to provide basic operation. Description: the nte7400 contains four independent 2-input nand gates in a 14-lead plastic dip type package. Sn5400, sn54ls00, and sn54s00 are characterized for operation over the full military temperature range of 55?C to 125?C 2 applications. A standard ttl nand gate with open collector output. The following links are to local copies of pages from the ttl data book. Ordering code: devices also available in tape and reel. Figure 5 there is another configuration that implies the same output of previous circuit figure 6 r1 vcc vb vcc 0 r1 va r2 r2 r2 0 vcc vout 1 2 3 r2 r2 1 2 3 re vb va. Figure 1 internal schematic of ttl nand gate r3 vcc d1 r1 r2 q3 q4 q2 q1 d2 d3 a b y. ?Le 01256 question 4 the following is an internal schematic of a ttl logic gate. 420
This device contains four independent gates each of which performs the logic nand function. As the name suggests, the transistor performs two functions like logic as well as amplifying. 796 You may wonder why the nand gate is so popular in the ttl logic24 pages. The functional operation of the ttl nand gate is summarized in figure ttl-2a. The sn54 / 74ls132 contains four 2-input nand gates which accept stan- dard ttl input signals and provide standard ttl output levels. What are the logic low and high levels of ttl ics and cmos ics? 5. N if any input goes low, the base current is diverted out through the input diode. 3 the ttl nand gate f - free download as pdf file, text file. We will first study the transfer characteristic of a ttl-nand gate using the 74f00 parts. The diode from the pn junction results in the net effect being the minimum voltage of a, b, and c determining how transistor t1 behaves. Nand gates are basic logic gates, and as such they are recognised in ttl. Below is the circuit of a totem-pole nand gate, which has got three stages. 4 in the following schottky ttl logic, the schottky diode. Fan-out specifies the number of standard loads that the output of a gate can drive without impairing its normal operation. Click on the inputs on the bottom to toggle their state. Cmos logic gates elementary logic gates are even more easily built from cmos ?Eld effect transistors. Directions: by adding another input to the ttl inverter, a ttl nand gate can be made. Figure 7 shows the ttl circuit with all inputs high and the output low.
The transistor-transistor logic ttl is a logic family made up of bjts bipolar junction transistors. 7400 is as shown below: the circuit consists of multiple-emitter input transistor q1,41 pages. Suppose we altered our basic open-collector inverter circuit, adding a second input terminal just like the first. Let us take a closer look at a typical ttl de- vice and see what the basic input-output characteristics are. Fast and ls ttl data triple 3-input nand gate 14 13 12 11 10 123456 vcc 8 7 gnd guaranteed operating ranges symbol parameter min typ max unit vcc supply voltage 54 74 4. However, when we examine this circuit, we see that the nand function is actually the simplest, most natural mode of operation for this ttl design. Inputs include clamp diodes that enable the use of current limiting resistors to interface inputs to voltages in excess of vcc. 956 In this lab activity, the transistor transistor logic ttl circuit inverter not gate and 2 input nand gate configurations are examined. 0 introduction to logic families in this module, the differences and similarities between the various families of logic ics available are described, along. Ttlquad 2?Input positive nand gate description: the nte7400 contains four independent 2?Input nand gates in a 14?Lead plastic dip type package. The transistors used in the circuit are all schottky transistors with the exception.
Symbol also shows a separation between the gate and the other terminals to indicate the. Connect the output of the seventh gate back to one of the inputs on the first gate as shown below. The ttl nand gate of figure 3 is the same as the ttl and nand gate of figure 1 with a totem pole output stage. Connect one input of the nand gate to 5 v and the other. Leveraging msi components, design simple frequency dividers and counter circuits. 1036 This work presents the design and electrical characterization of in-house-fabricated 2-input nand gate. The circuit, as we can see, is nearly the same as that of the high-power ttl nand gate. 4 a basic 2-input ttl nand gate: a circuit diagram; b the logic symbol for a. This enables the use of current limiting resistors to interface inputs to voltages in excess of vcc. Ttl nand gate: to build a ttl nand gate, transistor t1 is built so that the base has several inputs. General description the 74hc00; 74hct00 is a quad 2-input nand gate. In order to turn this nor gate circuit into an or gate, we would have to invert the output logic level with another transistor stage, just like we did with the nand-to-and gate example: or gate truth table. The standard part number for the ttl nand gate is 7400. However, a nor gate can be designed using an extra inverter transistors just as in the case of dtl nor gate. In the ttl nand gate of figure 1, applying a logic 1 input voltage to both emitter inputs of t1 reverse-biases both base-emitter junctions, causing current to flow through r1 into the base of t2, which is driven into saturation. Ttl nand gates typically provide 1, 2, 4, or 8 inputs.
Ttl integrated circuits provide multiple inputs to nand gates by designing transistors with multiple emitters on the chip. Connect the ttl inverter circuit, shown on figure 8. Synopsis: in this lab we will use ttl inverter chip 74ls04 and ttl schmitt trigger nand gate chip 74ls13 to observe the transfer characteristics of ttl gates and the phenomenon of hysteresis. In actuality, the two input transistors j t11 and t12 comprise a single dual emitter transistor with a common collector. Dc characteristics over operating temperature range2 pages. 43 All other logic gates using nand gate or nor gate alone. Will make a nand or a nor gate and the logic level is automatically restored for each gate. While in principle, you can think of an 8-input nand gate, in practice, it is built using two 4-input nand gates, a 2-input nor gate, and an inverter. Also available as dual 2-input positive-nand gate in small-outline ps package. Snx400, snx4ls00, and snx4s00 quadruple 2-input positive-nand gates datasheet rev. Ttl is the largest family of digital ics, but the cmos family is growing rapidly. Digital logic gates nand and nor are called universal logic gate because we can construct all other logic gates using nand gate or nor gate alone. Nand gate is the basic gate or building block of this logic family.
A single multi emitter transistor replaces input diodes and the series diode of dtl. Circuit schematic and operation of 7400 ttl nand gate the schematic diagram of the 7400 ttl nand gate, as specified by the manufacturer, is shown in fig. In the earlier section on nand gates, this type of gate was created by taking an and gate and increasing its complexity by adding an inverter not gate to the output. Ttl and cmos logic family is most widely used ic technologies. 3500 volts 14 13 12 11 10 123456 vcc 8 7 gnd guaranteed operating ranges symbol parameter min typ max unit vcc supply voltage 54 74 4. Dm7400 quad 2-input nand gates dm7400 quad 2-input nand gates general description this device contains four independent gates each of which performs the logic nand function. Specify by appending the suffix letter x to the ordering code. Ttl gate with totem-pole output circuit model with inputs high. 82 In digital electronics, a nand gate is a logic gate which produces an output which is false. The best examples of ttl are logic gates namely the 7402 nor gate. If more than eight inputs are required, then a network of nand gates must be employed. The circuit shown is that of one of the four gates inside a quad two-input nand type 74s00 or 54s00. Equipment and materials 5v dc power supply 1pc 74ls00 quad 2input nand gate 1pc 74ls04 hex inverter gate.
By inverting the nand gate by using simple transistor as an inverter we may have a simple and rtl gate. Ttl nand gates can be designed with any desired number of inputs simply by changing the number of diodes in the diode and gate in the figure. This is an nor gate implemented using transistor-transistor logic. The models for the transistors are shown as before, except diode d and transistor q4 are added and shown as cutoff. The analysis of this circuit proceeds exactly the same as before. The totem-pole output stage consists of a cc with an additional 120 ohm resistor stage stacked on top of a ce stage with a diode in between. The circuit diagram for a 2-input ls-ttl nand gate, part number 74ls00, is shown in figure ttl-1. Ttl inputs are the emitters of bipolar transistors. 317 Advantages are that, it is fast, cheap and easy to use. Ee201: digital circuits and systems 5 digital circuitry page 14 of 31 a1 b1 c1. If either of the inputs a or b is low it will forward bias the emitter junction of the multi-emitter transistor4 pages. The transistor transistor logic ttl family has heavily dependence on12 pages.
Ttl logic circuits are so commonly used that everyone must know a. Gate can feed and the gate must be same logic family. If a logi c family is said to have a fan-in of 4 if in general the maximum number of inputs on gates in that family is 4. 6: circuit for measuring ttl gate response by method i. 3 the output of a nand gate is connected to a certain number of not gates at. Truth table each gate: inputs output a b y h h l l x h x l h h. 480 The nand gate figure 2 shows a two input ttl nand gate. The hc03a nand gate has, as its outputs, a high?Performance. Shown is simplified schematic of a ttl inverter top and two-input ttl nand gate bottom. A standard load is defined to be the amount of current required. Find out fan-out, noise margin components required: 1.