1. Information Storage and Spintronics 11
Atsufumi Hirohata
Department of Electronic Engineering
15:00 Monday, 05/November/2018 (J/Q 004)

2. Quick Review over the Last Lecture
DRAM :
Read-out operation of 1C1T :
Data stored in a capacitor.
“1”-data :
1 V + ΔV = 2 V
 Electric charge needs to be refreshed.
 DRAM requires large power consumption.
3.6 V ON
2 V = 1 V + ΔV
Refresh operation of 1C1T :
“0”-data :
1 V – ΔV = 0 V
3.6 V ON
0 V = 1 V – ΔV * *

3. 11 Static Random Access Memory
Volatile memory developmement
6T-SRAM architecture
Read / write operation
1T-SRAM
Various ROMs

4. Memory Types Rewritable Volatile Dynamic DRAM Static SRAM Non-volatile
MRAM
FeRAM
PRAM
Read only
Non-volatile
Static
PROM
Mask ROM
Read majority
(Writable)
Non-volatile
Static
Flash
EPROM * 4

5. Manchester Automatic Digital Machine
In 1949, Frederic C. Williams and Tom Kilburn developed Manchester Mark 1 :
One of the earliest
stored-programme computers * ** 5

6. Williams-Kilburn Tube
Cathode-ray tube to store data :
Utilise a minor change of electron charges
at a fluorescent screen when an electron
hit it. * 6

7. Delay Line Memory
In 1947, John P. Eckart invented a mercury delay line memory :
Utilise an ultrasonic wave
generated by a transducer
to store a data. * 7

8. An array of cathode-ray tubes is used to store data electrostatically.
Selectron Tube
In 1953, Jan A. Rajchman (RCA) invented a selectron tube :
An array of cathode-ray tubes is used to store data electrostatically. * ** 8

9. Static Random Access Memory (SRAM)
No need to dynamically refresh data.
 Even so, the data is lost once the power is off.
Flip flop is used to store data.
 Low power consumption * 9

10. 6T-SRAM Read Operation A standard SRAM cell :* 10

11. 6T-SRAM Write Operation* 11

12. 1T-SRAM Pseudo SRAM developed by MoSys :
By comparing with the conventional 6T-SRAM,
< 1/3 area
< 1/2 power consumption
Easy to be embeded
Simple interface
Similar to SRAM performance
Lower latency as compared with DRAM
High fidelity (< 1 FIT / Mbit, FIT : failure in time of 10 9 hours) * ** 12

13. Advantages of 1T-SRAM
Comparison between 1T-SRAM, embedded SRAM (eSRAM) and 6T-SRAM : * 13

14. Mask ROM Read-only memory made by a photo-mask : Cheap
Simple structure
Ideal for integration
Initial mask fabrication cost
Lead time for mask fabrication
No design change without mask replacement * 14

15. Programmable ROM (PROM)
PROM bipolar cell : * 15

16. PROM Architecture PROM architecture :* 16

17. Erasable PROM UV-light can erase stored data :* * 17

18. Electrically EPROM (EEPROM)
In 1978, George Perlegos (Intel) developed electrical erasing mechanism :
Similar to flash memory
Individual bits are erasable.
Rewritable by simply writing a new data
Rewritability > 100k times
Small capacity (~ a few 10 bytes)
More complicated architecture as compared with flash memory
Higher cost for fabrication as compared with flash memory * 18

19. EEPROM Usages EEPROM is used in various applications :* 19

20. Connections between the Components
Connections between CPU, in/outputs and storages : *