dp8421a National Semiconductor Corporation, dp8421a Datasheet - Page 45

• Manufacturer Part Number: dp8421a
• Description: Microcmos Programmable 256k/1m/4m Dynamic Ram Controller/drivers
• Manufacturer: National Semiconductor Corporation

Number
13 0 AC Timing Parameters
Unless otherwise stated V
per bank including trace capacitance (Note 2)
Two different loads are specified
C
C
50
51
52
53
54
55
56
L
L
e
e
50 pF loads on all outputs except
150 pF loads on Q0 – 8 9 10 and WE or
Symbol
tD1
tD2
tD3a
tD3b
tD4
tD5
tD6
(AREQ or AREQB Negated to RAS
Negated) Minus (CLK High to RAS
Asserted)
(CLK High to Refresh RAS Negated)
Minus (CLK High to RAS Asserted)
(ADS Asserted to RAS Asserted
(Mode 1)) Minus (AREQ Negated
to RAS Negated)
(CLK High to RAS Asserted (Mode 0))
Minus (AREQ Negated to RAS Negated)
(ECAS Asserted to CAS Asserted)
Minus (ECAS Negated to CAS Negated)
(CLK to Refresh RAS Asserted) Minus
(CLK to Refresh RAS Negated)
(AREQ Negated to RAS Negated)
Minus (ADS Asserted to RAS
Asserted (Mode 1))
CC
Parameter Description
e
5 0V
Difference
g
10% 0 C
(Continued)
k
T
A k
70 C the output load capacitance is typical for 4 banks of 18 DRAMs
45
Min
b
7
C
C
C
H
H
H
8420A 21A 22A-20
C
e
e
e
L
Max
16
13
12
50 pF loads on all outputs except
125 pF loads on RAS0 – 3 and CAS0 – 3 and
380 pF loads on Q0 – 8 9 10 and WE
4
4
7
6
Min
b
7
C
H
Max
16
13
12
4
4
7
6
Min
b
7
8420A 21A 22A-25
C
L
Max
14
11
10
4
4
7
6
Min
b
7
C
H
Max
14
11
10
4
4
7
6