1. Jazan University, Jazan KSA
Chapter 5
Lecture 11
Faheem
Lecturer, CNET Dept.,
Jazan University, Jazan KSA
Internal Memory

2. Topics in this chapter Semi Conductor Main Memory.
Dynamic Random Access Memory [DRAM].
Static Random Access Memory [SRAM] and
Read Only Memory [ROM]

3. Semiconductor Main Memory
In old computers, the most common form of random-access memory was an array of ferromagnetic material referred as cores. Hence, main memory was also called as core. Today due to development of microelectronics magnetic core memory is vanished, and the use of semiconductor chips for main memory is universal for all computers.
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4. Main Memory Organization
The basic element of a semiconductor memory is the memory cell, all semiconductor memory cells share certain properties:
They exhibit two stable (or semi-stable) states, which can be used to represent binary 1 and 0.
They are capable to write into, to set the state.
They are capable of being read to sense the state.
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5. Set and sense state

6. Main Memory Cell
The cell has three functional terminals for carrying an electrical signal.
The select terminal, selects a memory cell for a read or write operation.
The control terminal indicates read or write.
For writing, data terminal provides an electrical signal that sets the state of the cell to 1 or 0.
For reading, this terminal is used for output of the cell’s state,
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7. Semiconductor Memory Types
The table shows all Semiconductor Memory Types
The most common is Random Access Memory.
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8. Random Access Memory [RAM]
The memory is accessed in random manner that’s why it is called as random access memory.
It is Read/Write memory
It is Volatile memory
It is a Temporary storage
Its of two type Static or dynamic.

9. Dynamic RAM Bits stored as charge in capacitors Charges leak
Need refreshing even when powered
Simpler construction
Smaller per bit
Less expensive
Need refresh circuits
Slower
Main memory
Analogue
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10. Dynamic RAM Structure
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11. DRAM Operation Write Address line active when bit read or written
Transistor switch closed (current flows)
Write
Voltage to bit line
High for 1 low for 0
Then signal address line
Transfers charge to capacitor.
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12. DRAM Operation Read Read Address line selected
transistor turns on
Charge from capacitor fed via bit line to sense amplifier
Compares with reference value to determine 0 or 1
Capacitor charge must be restored
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13. Thank you!!!

14. On 20th of April 2016 Wednesday [12 to 01] On Chapter 3 and 4.
Exam 2
On 20th of April 2016
Wednesday [12 to 01]
On Chapter 3 and 4.