ISSI IS41C16256, IS41LV16256 User Manual

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IS41C16256

IS41LV16256 ISSI

256K x 16 (4-MBIT) DYNAMIC RAM JUNE 2000
WITH EDO PAGE MODE

®

FEATURES

• TTL compatible inputs and outputs

• Refresh Interval: 512 cycles/8 ms

• Refresh Mode : RAS-Only, CAS-before-RAS
(CBR), and Hidden

• JEDEC standard pinout

• Single power supply
5V ± 10% (IS41C16256)

3.3V ± 10% (IS41LV16256)

• Byte Write and Byte Read operation via two CAS

• Extended Temperature Range -30oC to 85oC

• Industrail Temperature Range -40oC to 85oC

DESCRIPTION

The

ISSI

IS41C16256 and IS41LV16256 are 262,144 x 16-bit
high-performance CMOS Dynamic Random Access Memory. Both
products offer accelerated cycle access EDO Page Mode. EDO
Page Mode allows 512 random accesses within a single row with
access cycle time as short as 10ns per 16-bit word. The Byte Write
control, of upper and lower byte, makes the IS41C16256 and
IS41LV16256 ideal for use in 16 and 32-bit wide data bus systems.

These features make the IS41C16256 and IS41LV1626 ideally
suited for high
high-performance computing systems, and peripheral applications.

The IS41C16256 and IS41LV16256 are packaged in 40-pin
400-mil SOJ and TSOP (Type II).

band-width

graphics,

KEY TIMING PARAMETERS

Parameter -35 -50 -60 Unit

Max. RAS Access Time (tRAC) 355060ns
Max. CAS Access Time (tCAC) 101415ns
Max. Column Address Access Time (tAA)182530ns
Min. EDO Page Mode Cycle Time (tPC)122025ns
Min. Read/Write Cycle Time (tRC) 60 90 110 ns

digital signal processing,

PIN CONFIGURATIONS

40-Pin TSOP (Type II) 40-Pin SOJ

1

VCC

2

I/O0

3

I/O1

4

I/O2

5

I/O3

6

VCC

7

I/O4

8

I/O5

9

I/O6

10

I/O7

11

NC

12

NC

13

WE

14

RAS

15

NC

16

A0

17

A1

18

A2

19

A3

20

VCC

ISSI reserves the right to make changes to its products at any time without notice in order to improve design and supply the best possible product. We assume no responsibility for any
errors which may appear in this publication. © Copyright 2000, Integrated Silicon Solution, Inc.

40

GND

39

I/O15

38

I/O14

37

I/O13

36

I/O12

35

GND

34

I/O11

33

I/O10

32

I/O9

31

I/O8

30

NC

29

LCAS

28

UCAS

27

OE

26

A8

25

A7

24

A6

23

A5

22

A4

21

GND

VCC

I/O0
I/O1
I/O2
I/O3

VCC

I/O4
I/O5
I/O6
I/O7

NC
NC

WE

RAS

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

40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21

GND
I/O15
I/O14
I/O13
I/O12
GND
I/O11
I/O10
I/O9
I/O8
NC
LCAS
UCAS
OE
A8
A7
A6
A5
A4
GND

PIN DESCRIPTIONS

A0-A8 Address Inputs
I/O0-15

WE Write Enable
OE Output Enable
RAS Row Address Strobe
UCAS
LCAS

Vcc Power
GND Ground
NC No Connection

Data Inputs/Outputs

Upper Column Address Strobe
Lower Column Address Strobe

Integrated Silicon Solution, Inc. — 1-800-379-4774

Rev. J

06/29/00

1

IS41C16256

IS41LV16256 ISSI

FUNCTIONAL BLOCK DIAGRAM

OE
WE

®

LCAS

UCAS

RAS

A0-A8

CAS

CLOCK

GENERATOR

RAS

CLOCK

GENERATOR

REFRESH
COUNTER

ADDRESS
BUFFERS

WE

CAS WE

RAS

CONTROL

LOGICS

DATA I/O BUS

COLUMN DECODERS

SENSE AMPLIFIERS

MEMORY ARRAY

262,144 x 16

ROW DECODER

OE

CONTROL

LOGIC

OE

I/O0-I/O15

DATA I/O BUFFERS

2

Integrated Silicon Solution, Inc. — 1-800-379-4774

Rev. J

06/29/00

IS41C16256

IS41LV16256 ISSI

TRUTH TABLE

Function RAS LCAS UCAS WE OE Address tR/tC I/O

Standby H H H X X X High-Z
Read: Word L L L H L ROW/COL DOUT
Read: Lower Byte L L H H L ROW/COL Lower Byte, DOUT

Upper Byte, High-Z

Read: Upper Byte L H L H L ROW/COL Lower Byte, High-Z

Upper Byte, DOUT
Write: Word (Early Write) L L L L X ROW/COL DIN
Write: Lower Byte (Early Write) L L H L X ROW/COL Lower Byte, DIN

Upper Byte, High-Z
Write: Upper Byte (Early Write) L H L L X ROW/COL Lower Byte, High-Z

Upper Byte, DIN
Read-Write
EDO Page-Mode Read

EDO Page-Mode Write

(1,2)

LLLH→LL→H ROW/COL DOUT, DIN

(2)

1st Cycle: L H→ LH→L H L ROW/COL DOUT

2nd Cycle: L H→LH→L H L NA/COL DOUT

Any Cycle: L L→ HL→ H H L NA/NA DOUT

(1)

1st Cycle: L H→ LH→L L X ROW/COL DIN

2nd Cycle: L H→LH→L L X NA/COL DIN

®

EDO Page-Mode 1st Cycle: L H→LH→LH→LL→ H ROW/COL DOUT, DIN
Read-Write

Hidden Refresh

(1,2)

2nd Cycle: L H→LH→LH→ LL→H NA/COL DOUT, DIN

2)

Read L→H→ L L L H L ROW/COL DOUT

Write L→H→L L L L X ROW/COL DOUT
RAS-Only Refresh L H H X X ROW/NA High-Z
CBR Refresh

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. At least one of the two CAS signals must be active (LCAS or UCAS).

(3)

H→ L L L X X X High-Z

Integrated Silicon Solution, Inc. — 1-800-379-4774

Rev. J

06/29/00

3

IS41C16256

IS41LV16256 ISSI

®

Functional Description

The IS41C16256 and IS41LV16256 is a CMOS DRAM
optimized for high-speed bandwidth, low power applica­tions. During READ or WRITE cycles, each bit is uniquely
addressed through the 18 address bits. These are en­tered nine bits (A0-A8) 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 IS41C16256 and IS41LV16256 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 256K 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 IS41C16256 and IS41LV16256 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 IS41C16256 both BYTE READ and
BYTE WRITE cycle capabilities.

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 tRAS time has expired. A new
cycle must not be initiated until the minimum precharge
time tRP, tCP has elapsed.

Refresh Cycle

To retain data, 512 refresh cycles are required in each
8 ms period. There are two ways to refresh the memory.

1. By clocking each of the 512 row addresses (A0 through
A8) with RAS at least once every 8 ms. Any read, write,
read-modify-write or RAS-only cycle refreshes 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 ad­dresses 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.

Extended Data Out Page Mode

EDO page mode operation permits all 512 columns within
a selected row to be randomly accessed at a high data
rate.

In EDO page mode read cycle, the data-out is held to the
next CAS cycle’s falling edge, instead of the rising edge.
For this reason, the valid data output time in EDO page
mode is extended compared with the fast page mode. In
the fast page mode, the valid data output time becomes
shorter as the CAS cycle time becomes shorter. There­fore, in EDO page mode, the timing margin in read cycle
is larger than that of the fast page mode even if the CAS
cycle time becomes shorter.

In EDO page mode, due to the extended data function, the
CAS cycle time can be shorter than in the fast page mode
if the timing margin is the same.

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 speci­fied by tAR. Data Out becomes valid only when tRAC, tAA,
tCAC and tOEA are all satisfied. As a result, the access time
is dependent on the timing relationships between these
parameters.

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.

4

The EDO page mode allows both read and write opera­tions during one RAS cycle, but the performance is
equivalent to that of the fast page mode in that case.

Power-On

After application of the VCC supply, an initial pause of
200 µs is required followed by a minimum of eight initial­ization cycles (any combination of cycles containing a
RAS signal).

During power-on, it is recommended that RAS track with
VCC or be held at a valid VIH to avoid current surges.

Integrated Silicon Solution, Inc. — 1-800-379-4774

Rev. J

06/29/00

IS41C16256

IS41LV16256 ISSI

®

ABSOLUTE MAXIMUM RATINGS

(1)

Symbol Parameters Rating Unit

VT Voltage on Any Pin Relative to GND 5V –1.0 to +7.0 V

3.3V -0.5 to 4.6 V

CC Supply Voltage 5V –1.0 to +7.0 V

V

3.3V -0.5 to 4.6 V
IOUT Output Current 50 mA
PD Power Dissipation 1 W

A Commercial Operation Temperature 0 to +70 °C

T

Extended Temperature –30 to +85 °C
Industrail Temperature –40 to +85 °C

TSTG Storage Temperature –55 to +125 °C

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 Parameter Min. Typ. Max. Unit

VCC Supply Voltage 5V 4.5 5.0 5.5 V

3.3V 3.0 3.3 3.6

VIH Input High Voltage 5V 2.4 — VCC + 1.0 V

3.3V 2.0 — VCC + 0.3

VIL Input Low Voltage 5V –1.0 — 0.8 V

3.3V –0.3 — 0.8

TA Commercial Ambient Temperature 0 — 70 °C

Extended Ambient Temperature –30 — 85 °C
Industrail Ambient Temperature –40 — 85 °C

CAPACITANCE

(1,2)

Symbol Parameter Max. Unit

CIN1 Input Capacitance: A0-A8 5 pF
CIN2 Input Capacitance: RAS, UCAS, LCAS, WE, OE 7pF
CIO Data Input/Output Capacitance: I/O0-I/O15 7 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

Rev. J

06/29/00

5

IS41C16256

IS41LV16256 ISSI

®

ELECTRICAL CHARACTERISTICS

(1)

(Recommended Operation Conditions unless otherwise noted.)

Symbol Parameter Test Condition Speed Min. Max. Unit

IL Input Leakage Current Any input 0V ≤ VIN ≤ Vcc –10 10 µA

I

Other inputs not under test = 0V

I

IO Output Leakage Current Output is disabled (Hi-Z) –10 10 µA

0V ≤ VOUT ≤ Vcc
VOH Output High Voltage Level IOH = –2.5 mA 2.4 — V
VOL Output Low Voltage Level IOL = +2.1 mA — 0.4 V
I

CC1 Stand-by Current: TTL RAS, LCAS, UCAS ≥ VIH Commercial 5V — 3mA

Industrial 5V — 4
Commercial 3V — 2
Industrial 3V — 3

ICC2 Stand-by Current: CMOS RAS, LCAS, UCAS ≥ VCC – 0.2V 5V — 2mA

3V — 1

ICC3 Operating Current: RAS, LCAS, UCAS, -35 — 230 mA

Random Read/Write
Average Power Supply Current

ICC4 Operating Current: RAS = VIL, LCAS, UCAS, -35 — 220 mA

EDO Page Mode
Average Power Supply Current

(2,3,4)

(2,3,4)

Address Cycling, tRC = tRC (min.) -50 — 180

-60 — 170

Cycling tPC = tPC (min.) -50 — 170

-60 — 160

ICC5 Refresh Current: RAS Cycling, LCAS, UCAS ≥ VIH -35 — 230 mA

RAS-Only
Average Power Supply Current

(2,3)

tRC = tRC (min.) -50 — 180

-60 — 170

ICC6 Refresh Current: RAS, LCAS, UCAS Cycling -35 — 230 mA

(2,3,5)

CBR

tRC = tRC (min.) -50 — 180

Average Power Supply Current -60 — 170

Notes:

1. An initial pause of 200 µs is required after power-up followed by eight RAS refresh cycles (RAS-Only or CBR) before proper device
operation is assured. The eight RAS cycles wake-up should be repeated any time the t

2. Dependent on cycle rates.

3. Specified values are obtained with minimum cycle time and the output open.

4. Column-address is changed once each EDO page cycle.

5. Enables on-chip refresh and address counters.

REF refresh requirement is exceeded.

6

Integrated Silicon Solution, Inc. — 1-800-379-4774

Rev. J

06/29/00