WorksheetsDIGITAL LOGIC FAMILIES
Total questions: 56
Worksheet time: 28mins
(RTL) RTL is the earliest form of logic circuit that primarily uses:
Diodes only
Transistors and resistors
MOSFETs and capacitors
BJTs and op-amps
(RTL) The most common RTL gate is:
NAND
NOR
AND
OR
(RTL) Typical supply voltage for RTL is around:
5V
3.6V
12V
15V
(RTL) RTL circuits were used in:
Early computers like Apollo Guidance Computer
Smart sensors
CMOS VLSI chips
Fiber optic links
(RTL) RTL suffers mainly from:
Low power dissipation
High speed
High power consumption
Infinite fan-out
(RTL) The logic operation in RTL is mainly:
NAND
NOR
EX-OR
AND
(RTL) In RTL, the output HIGH voltage depends on:
Base resistance
Number of driven gates (fan-out)
Emitter resistor
Temperature
(RTL) RTL was replaced by:
TTL
CMOS
DTL
I²L
(DTL) DTL was developed to replace:
TTL
RTL
CMOS
I²L
(DTL) The basic logic gate implemented by DTL is:
AND
NOR
NAND
XOR
(DTL) The diodes in DTL are used for:
Amplification
Logical decision (ANDing)
Bias stabilization
Oscillation
(DTL) When both inputs are LOW, output is:
HIGH
LOW
Undefined
Floating
(DTL) DTL improves over RTL mainly by:
Using capacitors
Improving noise immunity
Reducing propagation delay
Increasing fan-out
(DTL) Typical propagation delay of DTL is:
5–10 ns
30–80 ns
1 ns
150 ns
(DTL) The transistor in DTL acts as:
OR gate
NOT gate
Amplifier
Comparator
(DTL) DTL was replaced by:
CMOS
TTL
ECL
HTL
(TTL) TTL stands for:
Transistor–Tunneling Logic
Transistor–Transistor Logic
Two-Transistor Logic
Triple Transistor Logic
(TTL) Basic logic gate in TTL:
NOR
AND
NAND
OR
(TTL) Typical supply voltage of TTL:
3V
5V
15V
9V
(TTL) TTL operates with propagation delay around:
100 ns
10–30 ns
1 ns
200 ns
(TTL) TTL IC series labeled as:
54xx and 74xx
40xx
60xx
80xx
(TTL) Fan-out refers to:
Voltage regulation
Number of loads an output can drive
Heat dissipation
Power factor
(TTL) Wired-AND logic uses:
Open-collector outputs
Pull-down resistor
Feedback capacitor
Coupled transformer
(TTL) Typical fan-out of standard TTL:
5
10
50
100
(Schottky TTL) Schottky TTL uses:
MOSFETs
Schottky diodes across transistor junctions
Varactors
Tunnel diodes
(Schottky TTL) The purpose of Schottky diode is to:
Increase saturation
Prevent deep saturation
Reduce base current
Increase leakage current
(Schottky TTL) Propagation delay of Schottky TTL is:
10 ns
2–4 ns
30 ns
100 ns
(Schottky TTL) Schottky TTL operates on:
3.3V
5V
12V
15V
(Schottky TTL) 5400 series TTL is for:
Consumer electronics
Military use
Automotive
Education
(Schottky TTL) 7400 series TTL is for:
Industrial
Military
Commercial
Aerospace
(Schottky TTL) Low Power Schottky TTL represented as:
74S
74LS
54F
54AS
(Schottky TTL) Advanced Schottky TTL provides:
Slow operation
Higher speed with more power
Low voltage
Higher impedance
(DCTL) DCTL stands for:
Differential Capacitive Transistor Logic
Direct-Coupled Transistor Logic
Double-Collector Transistor Logic
Diode-Coupled Transistor Logic
(DCTL) DCTL eliminates:
Diodes
Biasing resistors
Inductors
Capacitors
(DCTL) DCTL gates are based on:
NAND
NOR
XOR
AND
(DCTL) Current hogging occurs when:
Voltage exceeds breakdown
One transistor draws excess current
Supply voltage drops
All transistors switch together
(DCTL) DCTL circuits are prone to:
High noise margin
Low noise margin (~0.1–0.2V)
High input impedance
High power loss
(DCTL) DCTL’s major advantage is:
Low speed
Compactness and simplicity
Expensive fabrication
Large power dissipation
(DCTL) Common application of DCTL:
Large computers
Analog amplifiers
Filters
Communication systems
(DCTL) DCTL evolved into:
TTL
I²L
DTL
CMOS
(I²L) I²L is derived from:
ECL
DCTL
TTL
CMOS
(I²L) Key concept of I²L is:
Voltage injection
Current injection
Capacitive coupling
Transformer feedback
(I²L) I²L uses:
Multi-collector NPN transistors and PNP current injectors
Diodes and resistors
FETs and capacitors
Relays
(I²L) I²L best suited for:
Low-speed circuits
LSI and MSI applications
Power amplifiers
Analog converters
(I²L) I²L power dissipation is:
High
Moderate
Low
Variable
(I²L) I²L inverter uses:
Bipolar junction transistors
MOSFETs
Vacuum tubes
SCRs
(I²L) I²L used in:
Microcontrollers and memory circuits
Radio frequency amplifiers
LED drivers
AC regulators
(I²L) Main advantage of I²L fabrication:
Complex process
Simple, low-cost, high-density design
Requires many resistors
Needs large die area
(ECL) ECL is known for being:
Slowest
Fastest logic family
Lowest power
Most economical
(ECL) Transistors in ECL operate in:
Saturation
Active region (never saturate)
Cutoff
Breakdown
(ECL) Typical propagation delay of ECL:
10
Zero
Very high (>10)
(ECL) ECL uses emitters that are:
Coupled together
Isolated
Bypassed
Grounded individually
(ECL) ECL avoids saturation to:
Save power
Eliminate storage delay
Increase voltage margin
Reduce temperature effects
(HTL) HTL operates at higher voltages (~):
3.6V
5V
15V
1.8V
(HTL) HTL’s main advantage is:
Speed
High noise immunity
Small size
Low voltage operation
(HTL) HTL uses ______ instead of diodes for thresholding:
LEDs
Zener diodes
Schottky diodes
Varactors
