dp8421a National Semiconductor Corporation, dp8421a Datasheet - Page 49

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

300
301a
301b
302
303
304
305
306
307
308a
308b
308c
308d
309
310
311
312
313
314
315
316
Number
13 0 AC Timing Parameters
Unless otherwise stated V
per bank including trace capacitance (Note 2)
Two different loads are specified
C
C
L
L
e
e
50 pF loads on all outputs except
150 pF loads on Q0 – 8 9 10 and WE or
tSCSCK
tSALECKNL
tSALECKL
tWALE
tSBADDCK
tSADDCK
tHASRCB
tSRCBAS
tPCKRL
tPCKCL0
tPCKCL1
tPCKCL2
tPCKCL3
tHCKALE
tSWINCK
tPCSWL
tPCSWH
tPCLKDL1
tPALEWL
tPCKCV0
Symbol
CS Asserted to CLK High
ALE Asserted Setup to CLK High
Not Using On-Chip Latches or
if Using On-Chip Latches and
B0 B1 Are Constant Only 1 Bank
ALE Asserted Setup to CLK High
if Using On-Chip Latches if B0 B1
Can Change More Than One Bank
ALE Pulse Width
Bank Address Valid Setup to CLK High
Row Column Valid Setup to
CLK High to Guarantee
tASR
Row Column Bank Address
Held from ALE Negated
(Using On-Chip Latches)
Row Column Bank Address
Setup to ALE Negated
(Using On-Chip Latches)
CLK High to RAS Asserted
CLK High to CAS Asserted
(t
CLK High to CAS Asserted
(t
CLK High to CAS Asserted
(t
CLK High to CAS Asserted
(t
ALE Negated Hold from CLK High
WIN Asserted Setup to CLK High
to Guarantee CAS is Delayed
CS Asserted to WAIT Asserted
CS Negated to WAIT Negated
CLK High to DTACK Asserted
(Programmed as DTACK0)
ALE Asserted to WAIT Asserted
(CS is Already Asserted)
AREQ Negated to CLK High That Starts
Access RAS to Guarantee tASR
(Non-Interleaved Mode Only)
CLK High to Column
Address Valid
(t
RAH
RAH
RAH
RAH
RAH
CC
e
e
e
e
e
e
e
Parameter Description
5 0V
0 ns
15 ns t
15 ns t
25 ns t
25 ns t
15 ns t
Mode 0 Access
g
10% 0 C
ASC
ASC
ASC
ASC
ASC
e
e
e
e
e
(Continued)
0 ns)
10 ns)
0 ns)
10 ns)
0 ns)
k
T
A k
e
70 C the output load capacitance is typical for 4 banks of 18 DRAMs
0 ns
49
b
Min
C
C
C
14
16
29
18
20
11
10
41
3
0
21
H
H
H
8420A 21A 22A-20
e
e
e
C
L
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
Max
101
27
81
91
91
26
30
40
35
78
b
Min
14
16
29
18
20
15
10
45
3
0
21
C
H
Max
109
32
89
99
99
26
30
40
35
87
b
Min
13
15
29
13
18
11
34
8
2
0
16
8420A 21A 22A-25
C
L
Max
22
72
82
82
92
22
25
32
29
66
b
Min
13
15
29
13
18
16
39
8
2
0
16
C
H
Max
26
79
89
89
99
22
25
32
29
75