APPENDIX A <REFERENCE> EXTERNAL DEVICE INTERFACE TIMINGS

A.1 DRAM (70ns)

DRAM interface setup examples – 70ns

Operating

RAS precharge

RAS cycle

CAS cycle

Refresh RAS pulse

Refresh RPC delay

frequency

cycle

width

 

 

 

20MHz

2

1

2

2

1

25MHz

2

1

2

2

1

33MHz

2

2

3

3

1

DRAM interface timing – 70ns

DRAM interface

 

Unit: ns

 

33MHz

25MHz

20MHz

Parameter

Symbol

Min.

Max.

Cycle

Time

Cycle

Time

Cycle

Time

<Common parameters>

Random read/random write cycle time

tRC

130

7

210

5

200

5

250

#RAS precharge time

tRP

50

2

60

2

80

2

100

#RAS pulse width

tRAS

70

10000

5

150

3

120

3

150

#CAS pulse width

tCAS

20

10000

2.5

75

1.5

60

1.5

75

Row address setup time

tASR

0

0.5

15

0.5

20

0.5

25

Row address hold time

tRAH

10

1.5

45

0.5

20

0.5

25

Column address setup time

tASC

0

0.5

15

0.5

20

0.5

25

#RAS#CAS delay time

tRCD

20

2.0

60

1.0

40

1.0

50

#RAScolumn address delay time

tRAD

15

1.5

45

0.5

20

0.5

25

<Read-cycle parameters>

 

 

 

 

 

 

 

 

 

#RAS access time

tRAC

70

4.5

135

2.5

100

2.5

125

#CAS access time

tCAC

20

2.5

75

1.5

60

1.5

75

Address access time

tAA

35

3.0

90

2.0

80

2.0

100

#OE access time

tOAC

20

4.5

135

2.5

100

2.5

125

Output buffer turn-off time

tOFF

0

20

2

60

2

80

2

100

<Write-cycle parameters>

 

 

 

 

 

 

 

 

 

Data input hold time

tDH

15

2.5

75

1.5

60

1.5

75

<Fast-page mode>

 

 

 

 

 

 

 

 

 

Fast-page mode cycle time

tPC

45

3.0

90

2.0

80

2.0

100

Fast-page mode #CAS precharge time

tCP

10

0.5

15

0.5

20

0.5

25

Access time after #CAS precharge

tACP

40

3.0

90

2.0

80

2.0

100

<Refresh cycle>

 

 

 

 

 

 

 

 

 

#CAS setup time

tCSR

10

1.0

30

1.0

40

1.0

50

#CAS hold time

tCHR

10

2.5

75

1.5

60

1.5

75

#RAS precharge#CAS hold time

tPPC

10

1.0

30

1.0

40

1.0

50

#RAS pulse width (only in refresh cycle)

tRAS

70

10000

3.0

90

2.0

80

2.0

100

A-114

EPSON

S1C33L03 PRODUCT PART