26/03/2020

Semiconductor Memories Interview Question Answer - 2


16
Write the full form of RWM, RAM, ROM, PROM, EPROM, EAROM, EAPROM, EEROM and MROM


RWM : Read / write memory
RAM : Random access memory
ROM : Read only memory
PROM : Programmable read only memory
EPROM : Erasable programmable read only memory
EAROM : Electrically alterable read only memory
EAPROM : Electrically alterable programmable read only memory
EEROM : Electrically erasable read only memory
MROM : Mask programmable read only memory

17
Describe the three features of the RAM and ROM.


Feature of RAM
  • It is volatile.
  • High speed of operation.
  • All the unsaved data lost if the sudden power cut off.
  • There are basic two types of RAM : Static RAM and Dynamic RAM.

Features of ROM
  • It is non – volatile.
  • It cannot be used as read / write memory.
  • It stores data permanently.
  • There are following types of ROM : PROM, EPROM, EEPROM and MROM


18
Why the ROM is called as factory programmed ROM?


The contents in the ROM are permanently stored by the manufacturer at the time of fabrication therefore it is called as factory programmed ROM.

19
Describe the three features of PROM and EPROM.


Features of PROM
  • The programming in the PROM is done by the programmer.
  • Once the programming is done in the PROM, it cannot be altered.

Features of EPROM
  • The contents of the EPROM can be erased and also new contents can be stored in it.
  • It is non – volatile.
  • The contents of the EPROM can be erased either by certain electrical voltages or ultraviolet light exposing on them
  • Same device is used repeatedly.


20
How the data in the EPROM can be erased?


EPROM
  • The data in the EPROM can be erased either by ultra violet light exposing on them or certain electrical voltage.


21
Describe at least three features of FET based ICs and BJT based ICs.


Features of FET ICs ( Unipolar ICs )
  • It occupies less space as compared to BJT ICs.
  • It is easily manufactured.
  • It has large storage capacity as compared to BJT ICs.
  • The logic families MOS and CMOS use FET as main circuit element.

Features of BJT ICs ( Bipolar ICs )
  • It is faster than FET ICs.
  • It is applicable where high speed is prime consideration.
  • The logic families TTL, ECL, IIL use bipolar transistor as main circuit element.


22
Write the full form of SRAM and DRAM.


SRAM
  • Static random access memory

DRAM
  • Dynamic random access memory


23
Describe the three features of the DRAM.


Features of the DRAM
  • It consists of large number of memory cells in a single circuit.
  • Very low power consumption
  • It is only available in MOSFET circuits.
  • The DRAM based circuit must be refreshing periodically.


24
What is meaning of 32 × 8 ROM?


32 × 8 ROM
  • The ROM can store 32 bytes of data and it contains 32 possible addresses.
  • As there are 8 data outputs, each word contains 8 bits


25
Describe the function of the control input in the ROM.


The function of the control input in the ROM is to enable or disable the control outputs.

26
Which type of signal the ROM consists of?


The ROM consists of three set of signals
  • Address input
  • Control input
  • Data output


27
Why the read / write input is not available in the ROM?


The read / write input are not available in the ROM because the data cannot be written in the ROM during its normal state.

28
Define : Access time of memory


Access time
  • The propagation delay time between ROM input and appearance of data output is called as access time of memory.


29
What is significance of access time of memory?


Significance of access time
  • The access time measured the operating speed of the ROM.


30
Describe the different types of ROM. 


Different types of ROM
  • Programmable read only memory ( PROM )
  • Mask programmed read only memory ( MROM )
  • Erasable programmable read only memory ( EPROM )
  • Electrically erasable programmable read only memory                ( EEPROM )



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