sram (2)
TRANSCRIPT
-
7/29/2019 sram (2)
1/19
-
7/29/2019 sram (2)
2/19
-
7/29/2019 sram (2)
3/19
-
7/29/2019 sram (2)
4/19
-
7/29/2019 sram (2)
5/19
-
7/29/2019 sram (2)
6/19
1/23/2006 HY220: 6
Static RAM (SRAM)
Latch.
+ .
+ refreshing.+ .
- DRAM.
Dynamic RAM (DRAM)
dynamic node.
+ .
-! refreshing "leakage. # SRAM.
-# (noise).
data
write/read
data
write/read
C
storage cellstorage cell
-
7/29/2019 sram (2)
7/19
-
7/29/2019 sram (2)
8/19
-
7/29/2019 sram (2)
9/19
1/23/2006 HY220: 9
RowDeco
der
Row Address
Storage cell
Word line
Bit line
Sense amplifiers(read)/Drivers (write)
Column decoderColumn Address
Data I/O
Read: select desired bitsWrite: do not write unwanted bi
-
7/29/2019 sram (2)
10/19
1/23/2006 HY220: 10
Inside the RAM Device
Address inputs gointo decoder
Only one
output activeWord line selects a
row of bits (word)
Data passes
through OR gateEach binary cell
(BC) stores one bit
Input data stored if
Read/Write is 0
Output data drivenif Read/Write is 1
-
7/29/2019 sram (2)
11/19
1/23/2006 HY220: 11
Inside the SRAM Device
Note: delay primarilydepends on the numberof words
Delay not effected bysize of words
How many addressbits would I need for16 words?
Word
-
7/29/2019 sram (2)
12/19
1/23/2006 HY220: 12
Array Architecture
-
7/29/2019 sram (2)
13/19
1/23/2006 HY220: 13
Six transistor CMOS SRAM cell.Six transistor CMOS SRAM cell.
word
line
bit bit
$ word line (VDD) Latch bit bit Latch bit bit .
-
7/29/2019 sram (2)
14/19
1/23/2006 HY220: 14
SRAM BanksSRAM Banks
-
7/29/2019 sram (2)
15/19
1/23/2006 HY220: 15
Read OperationRead Operation
-
7/29/2019 sram (2)
16/19
1/23/2006 HY220: 16
Write Operation
-
7/29/2019 sram (2)
17/19
1/23/2006 HY220: 17
Example 1 : Combination of Read/Write
-
7/29/2019 sram (2)
18/19
-
7/29/2019 sram (2)
19/19
1/23/2006 HY220: 19
Summary
Memories provide storage for computers
Memories are organized in words
Selected by addresses
SRAMs store data in latches
Accessed by surrounding circuitry
RAM waveforms indicate the control signals needed for
access
Words in SRAMs are accessed with decoders
Only one word selected at a time