without notice. ISSI assumes no liability arising out of the application or use of any information, products or services described herein. Customers are advised to
obtain the latest version of this device specification before relying on any published information and before placing orders for products.
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. B
04/18/05
1
IS41LV16105B
FUNCTIONAL BLOCK DIAGRAM
ISSI
®
OE
WE
LCAS
UCAS
CAS
CLOCK
GENERATOR
WE
CONTROL
LOGICS
OE
CONTROL
LOGIC
OE
CAS
WE
RAS
RAS
CLOCK
GENERATOR
DATA I/O BUS
REFRESH
COUNTER
DATA I/O BUFFERS
ROW DECODER
RAS
COLUMN DECODERS
SENSE AMPLIFIERS
I/O0-I/O15
MEMORY ARRAY
1,048,576 x 16
ADDRESS
BUFFERS
A0-A9
2
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. B
04/18/05
IS41LV16105B
TRUTH TABLE
Function
Standby
Read: Word
Read: Lower Byte
Read: Upper Byte
Write: Word (Early Write)
Write: Lower Byte (Early Write)
Write: Upper Byte (Early Write)
Read-Write
(1,2)
Hidden Refresh
RAS-Only
Refresh
CBR Refresh
(4)
Read
(2)
Write
(1,3)
RAS
H
L
L
L
L
L
L
L
L→H→L
L→H→L
L
H→L
LCAS
H
L
L
H
L
L
H
L
L
L
H
L
UCAS
H
L
H
L
L
H
L
L
L
L
H
L
WE
X
H
H
H
L
L
L
H→L
H
L
X
X
OE
X
L
L
L
X
X
X
L→H
L
X
X
X
Address t
R
/t
C
X
ROW/COL
ROW/COL
ROW/COL
ROW/COL
ROW/COL
ROW/COL
ROW/COL
ROW/COL
ROW/COL
ROW/NA
X
I/O
ISSI
High-Z
D
OUT
Lower Byte, D
OUT
Upper Byte, High-Z
Lower Byte, High-Z
Upper Byte, D
OUT
D
IN
Lower Byte, D
IN
Upper Byte, High-Z
Lower Byte, High-Z
Upper Byte, D
IN
D
OUT
, D
IN
D
OUT
D
OUT
High-Z
High-Z
®
Notes:
1. These WRITE cycles may also be BYTE WRITE cycles (either
LCAS
or
UCAS
active).
2. These READ cycles may also be BYTE READ cycles (either
LCAS
or
UCAS
active).
3. EARLY WRITE only.
4. At least one of the two
CAS
signals must be active (LCAS or
UCAS).
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. B
04/18/05
3
IS41LV16105B
Functional Description
The IS41LV16105B is a CMOS DRAM optimized for high-
speed bandwidth, low power applications. During READ or
WRITE cycles, each bit is uniquely addressed through the
16 address bits. These are entered ten bits (A0-A9) at a
time. The row address is latched by the Row Address
Strobe (RAS). The column address is latched by the
Column Address Strobe (CAS).
RAS
is used to latch the
first nine bits and
CAS
is used the latter nine bits.
The IS41LV16105B has two
CAS
controls,
LCAS
and
UCAS.
The
LCAS
and
UCAS
inputs internally generates a
CAS
signal functioning in an identical manner to the single
CAS
input on the other 1M x 16 DRAMs. The key difference
is that each
CAS
controls its corresponding I/O tristate
logic (in conjunction with
OE
and
WE
and
RAS). LCAS
controls I/O0 through I/O7 and
UCAS
controls I/O8 through
I/O15.
The IS41LV16105B
CAS
function is determined by the first
CAS
(LCAS or
UCAS)
transitioning LOW and the last
transitioning back HIGH. The two
CAS
controls give the
IS41LV16105B both BYTE READ and BYTE WRITE cycle
capabilities.
ISSI
Write Cycle
®
A write cycle is initiated by the falling edge of
CAS
and
WE,
whichever occurs last. The input data must be valid at or
before the falling edge of
CAS
or
WE,
whichever occurs
last.
Refresh Cycle
To retain data, 1,024 refresh cycles are required in each
16 ms period. There are two ways to refresh the memory.
1. By clocking each of the 1,024 row addresses (A0
through A9) with
RAS
at least once every 16 ms. Any
read, write, read-modify-write or
RAS-only
cycle re-
freshes the addressed row.
2. Using a
CAS-before-RAS
refresh cycle.
CAS-before-
RAS
refresh is activated by the falling edge of
RAS,
while holding
CAS
LOW. In
CAS-before-RAS
refresh
cycle, an internal 9-bit counter provides the row ad-
dresses and the external address inputs are ignored.
CAS-before-RAS
is a refresh-only mode and no data
access or device selection is allowed. Thus, the output
remains in the High-Z state during the cycle.
Memory Cycle
A memory cycle is initiated by bring
RAS
LOW and it is
terminated by returning both
RAS
and
CAS
HIGH. To
ensures proper device operation and data integrity any
memory cycle, once initiated, must not be ended or
aborted before the minimum t
RAS
time has expired. A new
cycle must not be initiated until the minimum precharge
time t
RP
, t
CP
has elapsed.
Power-On
After application of the V
DD
supply, an initial pause of
200 µs is required followed by a minimum of eight
initialization cycles (any combination of cycles contain-
ing a
RAS
signal).
During power-on, it is recommended that
RAS
track with
V
DD
or be held at a valid V
IH
to avoid current surges.
Read Cycle
A read cycle is initiated by the falling edge of
CAS
or
OE,
whichever occurs last, while holding
WE
HIGH. The
column address must be held for a minimum time speci-
fied by t
AR
. Data Out becomes valid only when t
RAC
, t
AA
,
t
CAC
and t
OEA
are all satisfied. As a result, the access time
is dependent on the timing relationships between these
parameters.
4
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. B
04/18/05
IS41LV16105B
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
T
V
DD
I
OUT
P
D
T
A
Parameters
Voltage on Any Pin Relative to GND
Supply Voltage
Output Current
Power Dissipation
Commercial Operation Temperature
Extended Temperature
Industrial Temperature
Storage Temperature
3.3V
3.3V
Rating
–0.5 to +4.6
–0.5 to +4.6
50
1
0 to +70
–30 to +85
–40 to +85
–55 to +125
Unit
V
V
mA
W
°C
°C
°C
°C
ISSI
®
T
STG
Note:
1. Stress greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent
damage to the device. This is a stress rating only and functional operation of the device at these
or any other conditions above those indicated in the operational sections of this specification is not
implied. Exposure to absolute maximum rating conditions for extended periods may affect
reliability.
RECOMMENDED OPERATING CONDITIONS
(Voltages are referenced to GND.)
Symbol
V
DD
V
IH
V
IL
T
A
Parameter
Supply Voltage
Input High Voltage
Input Low Voltage
Commercial Ambient Temperature
Extended Ambient Temperature
Industrial Ambient Temperature
3.3V
3.3V
3.3V
Min.
3.0
2.0
–0.3
0
–30
–40
Typ.
3.3
—
—
—
—
—
Max.
3.6
V
DD
+ 0.3
0.8
+70
+85
+85
Unit
V
V
V
°C
°C
°C
CAPACITANCE
(1,2)
Symbol
C
IN
1
C
IN
2
C
IO
Parameter
Input Capacitance: A0-A9
Input Capacitance:
RAS, UCAS, LCAS, WE, OE
Data Input/Output Capacitance: I/O0-I/O15
Max.
5
7
7
Unit
pF
pF
pF
Notes:
1. Tested initially and after any design or process changes that may affect these parameters.
2. Test conditions: T
A
= 25°C, f = 1 MHz,
Integrated Silicon Solution, Inc. — 1-800-379-4774
京公网安备 11010802033920号
EEWORLD
