A420616 Series
Preliminary
Features
n
Organization: 1,048,576 words X 16 bits
n
Part Identification
- A420616 (1K Ref.)
n
Single 5.0V power supply/built-in VBB generator
n
Low power consumption
- Operating: 120mA (-45 max)
-
Standby: 1.0mA (TTL), 1.0mA (CMOS)
1.5mA (Self-refresh current)
n
High speed
- 45/50 ns RAS access time
- 20/22 ns column address access time
-
12/13 ns CAS access time
-
18/20 ns EDO Page Mode Cycle Time
n
Industrial operating temperature range: -40°C to 85°C
for -U
n
Fast Page Mode with Extended Data Out
n
Separate
CAS
(
UCAS
,
LCAS
) for byte selection
n
1K Refresh Cycle in 16ms
n
Read-modify-write, RAS -only, CAS -before- RAS ,
Hidden refresh capability
n
TTL-compatible, three-state I/O
n
JEDEC standard packages
-
400mil, 42-pin SOJ
-
400mil, 44/50 TSOP type II package
1M X 16 CMOS DYNAMIC RAM WITH EDO PAGE MODE
General Description
The A420616 is a new generation randomly accessed
memory for graphics, organized in a 1,048,576-word by
16-bit configuration. This product can execute Byte Write
and Byte Read operation via two
CAS
pins.
The A420616 offers an accelerated Fast Page Mode
This allow random access of up to 1024 words within a
row at a 56/50 MHz EDO cycle, making the A420616
ideally suited for graphics, digital signal processing and
high performance computing systems.
Pin Descriptions
Symbol
Description
Address Inputs
Data Input/Output
Row Address Strobe
Column Address Strobe for Lower Byte
(I/O
0
– I/O
7
)
Column Address Strobe for Upper Byte
(I/O
8
– I/O
15
)
WE
OE
VCC
VSS
NC
Write Enable
Output Enable
5.0V Power Supply
Ground
No Connection
Pin Configuration
n
SOJ
VCC
I/O
0
I/O
1
I/O
2
I/O
3
VCC
I/O
4
I/O
5
I/O
6
I/O
7
NC
NC
WE
RAS
NC
NC
A0
A1
A2
A3
VCC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
VSS
I/O
15
I/O
14
I/O
13
I/O
12
VSS
I/O
11
I/O
10
I/O
9
I/O
8
NC
LCAS
UCAS
OE
A9
A8
A7
A6
A5
A4
VSS
n
TSOP
VCC
I/O
0
I/O
1
I/O
2
I/O
3
VCC
I/O
4
I/O
5
I/O
6
I/O
7
NC
NC
NC
WE
RAS
NC
NC
A0
A1
A2
A3
VCC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
VSS
I/O
15
I/O
14
I/O
13
I/O
12
VSS
I/O
11
I/O
10
I/O
9
I/O
8
NC
NC
LCAS
UCAS
OE
A9
A8
A7
A6
A5
A4
VSS
A0 – A9
I/O
0
- I/O
15
RAS
LCAS
UCAS
cycle with a feature called Extended Data Out (EDO).
PRELIMINARY
A420616S
A420616V
(June, 2002, Version 0.2)
1
AMIC Technology, Inc.
A420616 Series
Selection Guide
Symbol
t
RAC
t
AA
t
CAC
t
OEA
t
RC
t
PC
Description
Maximum RAS Access Time
Maximum Column Address Access Time
Maximum CAS Access Time
Maximum Output Enable ( OE ) Access Time
Minimum Read or Write Cycle Time
Minimum EDO Cycle Time
-45
45
20
12
12
76
18
-50
50
22
13
13
84
20
Unit
ns
ns
ns
ns
ns
ns
Functional Description
The A420616 reads and writes data by multiplexing an 20-
bit address into a 10-bit row and 10-bit column address.
RAS
and
CAS
are used to strobe the row address and the
column address, respectively.
The A420616 has two
CAS
inputs:
LCAS
controls I/O
0
-
I/O
7
, and
UCAS
controls I/O
8
- I/O
15
,
UCAS
and
LCAS
function in an identical manner to
CAS
in that either will
generate an internal
CAS
signal. The
CAS
function and
timing are determined by the first
CAS
(
UCAS
or
LCAS
) to transition low and by the last to transition high.
Byte Read and Byte Write are controlled by using
LCAS
and
UCAS
separately.
A Read cycle is performed by holding the WE signal high
during RAS /
CAS
operation. A Write cycle is executed by
holding the WE signal low during RAS /
CAS
operation;
the input data is latched by the falling edge of WE or
CAS
, whichever occurs later. The data inputs and outputs
are routed through 16 common I/O pins, with RAS ,
CAS
,
WE and OE controlling the in direction.
EDO Page Mode operation all 1024(1K) columns within a
selected row to be randomly accessed at a high data rate.
A EDO Page Mode cycle is initiated with a row address
latched by RAS followed by a column address latched by
CAS
. While holding RAS low,
CAS
can be toggled to
strobe changing column addresses, thus achieving shorter
cycle times.
The A420616 offers an accelerated Fast Page Mode cycle
through a feature called Extended Data Out, which keeps
the output drivers on during the
CAS
precharge time (t
cp
).
Since data can be output after
CAS
goes high, the user is
not required to wait for valid data to appear before starting
the next access cycle. Data-out will remain valid as long as
RAS and OE are low, and WE is high; this is the only
characteristic which differentiates Extended Data Out
operation from a standard Read or Fast Page Read.
A memory cycle is terminated by returning both RAS and
CAS
high. Memory cell data will retain its correct state by
maintaining power and accessing all 1024(1K)
combinations of the 10-bit row addresses, regardless of
sequence, at least once every 16ms through any RAS
cycle (Read, Write) or RAS Refresh cycle ( RAS -only,
CBR, or Hidden). The CBR Refresh cycle automatically
controls the row addresses by invoking the refresh counter
and controller.
Power-On
The initial application of the VCC supply requires a 200 µs
wait followed by a minimum of any eight initialization cycles
containing a RAS clock. During Power-On, the VCC
current is dependent on the input levels of RAS and
CAS
.
It is recommended that RAS and
CAS
track with VCC or
be held at a valid V
IH
during Power-On to avoid current
surges.
PRELIMINARY
(June, 2002, Version 0.2)
2
AMIC Technology, Inc.
嵌入式系统
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
