ISSI IS42S16128-8T, IS42S16128-12T, IS42S16128-10T Datasheet

IS42S16128 ISSI

128K Words x 16 Bits x 2 Banks (4-MBIT)

®

SYNCHRONOUS DYNAMIC RAM

FEATURES

• Clock frequency: 125 MHz, 100 MHz, 83 MHz

• Two banks can be operated simultaneously and
independently

• Single 3.3V power supply

• LVTTL interface

• Programmable burst length
– (1, 2, 4, 8, full page)

• Programmable burst sequence:
Sequential/Interleave

• Auto refresh, self refresh

• 1K refresh cycles every 16 ms

• Random column address every clock cycle

• Programmable CAS latency (2, 3 clocks)

• Burst read/write and burst read/single write
operations capability

• Byte controlled by LDQM and UDQM

• Package 400-mil 50-pin TSOP II

PIN CONFIGURATIONS

50-Pin TSOP (Type II)

VCC

I/O0
I/O1

GNDQ

I/O2
I/O3

VCCQ

I/O4
I/O5

GNDQ

I/O6

I/O7
VCCQ
LDQM

WE
CAS
RAS

CS

A9
A8
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
23
24
25

50

GND

49

I/O15

48

I/O14

47

GNDQ

46

I/O13

45

I/O12

44

VCCQ

43

I/O11

42

I/O10

41

GNDQ

40

I/O9

39

I/O8

38

VCCQ

37

NC

36

UDQM

35

CLK

34

CKE

33

NC

32

NC

31

NC

30

A7

29

A6

28

A5

27

A4

26

GND

ORDERING INFORMATION
Commercial Range: 0

Frequency Speed (ns) Order Part No. Package

125 MHz 8 IS42S16128-8T 400-mil TSOP II
100 MHz 10 IS42S16128-10T 400-mil TSOP II

DESCRIPTION

ISSI's 4Mb Synchronous DRAM IS42S16128 is organized as
a 131072-word x 16-bit x 2-bank for improved performance.
The synchronous DRAMs achieve high-speed data transfer
using pipeline architecture. All inputs and outputs signals refer
to the rising edge of the clock input.

PIN DESCRIPTIONS

83 MHz 12 IS42S16128-12T 400-mil TSOP II

FEBRUARY 2000

A0-A9 Address Input

A0-A8 Row Address Input

A9 Bank Select Address

A0-A7 Column Address Input

I/O0 to I/O15 Data I/O
CLK System Clock Input
CKE Clock Enable

CS Chip Select

RAS Row Address Strobe Command

CAS Column Address Strobe Command
WE Write Enable

LDQM Lower Bye, Input/Output Mask

UDQM Upper Bye, Input/Output Mask

Vcc Power

GND Ground

VccQ Power Supply for I/O Pin

GNDQ Ground for I/O Pin

NC No Connection

⋅⋅

⋅C to 70

⋅⋅

⋅⋅

⋅C

⋅⋅

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.

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

Rev. A

03/13/00

1

®

IS42S16128 ISSI

PIN FUNCTIONS

Pin No. Symbol Type Function (In Detail)

20 to 24, A0-A8 Input Pin A0 to A8 are address inputs. A0-A8 are used as row address inputs during active

27 to 30 command input and A0-A7 as column address inputs during read or write command

input. A8 is also used to determine the precharge mode during other commands. If
A8 is LOW during precharge command, the bank selected by A9 is precharged, but
if A8 is HIGH, both banks will be precharged.
When A8 is HIGH in read or write command cycle, the precharge starts automati­cally after the burst access.
These signals become part of the OP CODE during mode register set command
input.

19 A9 Input Pin A9 is the bank selection signal. When A9 is LOW, bank 0 is selected and when high,

bank 1 is selected. This signal becomes part of the OP CODE during mode register
set command input.

16 CAS Input Pin CAS, in conjunction with the RAS and WE, forms the device command. See the

"Command Truth Table" item for details on device commands.

34 CKE Input Pin The CKE input determines whether the CLK input is enabled within the device.

When is CKE HIGH, the next rising edge of the CLK signal will be valid, and when
LOW, invalid. When CKE is LOW, the device will be in either the power-down mode,
the clock suspend mode, or the self refresh mode.

35 CLK Input Pin CLK is the master clock input for this device. Except for CKE, all inputs to this device

are acquired in synchronization with the rising edge of this pin.

18 CS Input Pin The CS input determines whether command input is enabled within the device.

Command input is enabled when CS is LOW, and disabled with CS is HIGH. The
device remains in the previous state when CS is HIGH.

2, 3, 5, 6, 8, 9, 11 I/O0 to I/O Pin I/O0 to I/O15 are I/O pins. I/O through these pins can be controlled in byte units
12, 39, 40, 42, 43, I/O15 using the LDQM and UDQM pins.
45, 46, 48, 49

14, 36 LDQM, Input Pin LDQM and UDQM control the lower and upper bytes of the I/O buffers. In read

UDQM mode, LDQM and UDQM control the output buffer. When LDQM or UDQM is LOW,

the corresponding buffer byte is enabled, and when HIGH, disabled. The outputs go
to the HIGH impedance state when LDQM/UDQM is HIGH. This function corre­sponds to OE in conventional DRAMs. In write mode, LDQM and UDQM control the
input buffer. When LDQM or UDQM is LOW, the corresponding buffer byte is
enabled, and data can be written to the device. When LDQM or UDQM is HIGH,
input data is masked and cannot be written to the device.

17 RAS Input Pin RAS, in conjunction with CAS and WE, forms the device command. See the

"Command Truth Table" item for details on device commands.

15 WE Input Pin WE, in conjunction with RAS and CAS, forms the device command. See the

"Command Truth Table" item for details on device commands.

7, 13, 38, 44 VCCQ Power Supply Pin VCCQ is the output buffer power supply.

1, 25 VCC Power Supply Pin VCC is the device internal power supply.

4, 10, 41, 47 GNDQ Power Supply Pin GNDQ is the output buffer ground.

26, 50 GND Power Supply Pin GND is the device internal ground.

The CKE is an asynchronous i

nput.

2

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

Rev. A

03/13/00

IS42S16128 ISSI

FUNCTIONAL BLOCK DIAGRAM

CLK

CKE

CS
RAS
CAS

WE

A9

COMMAND

DECODER

&

CLOCK

GENERATOR

MODE

REGISTER

ADDRESS

BUFFER

9

ROW

MEMORY CELL

512

9

ARRAY

BANK 0

DQM

®

A8

A7
A6
A5
A4
A3
A2
A1
A0

REFRESH

CONTROLLER

REFRESH

COUNTER

ROW

ADDRESS

LATCH

9

9

SELF

REFRESH

CONTROLLER

MULTIPLEXER

8

COLUMN

ADDRESS

9

BUFFER

ADDRESS LATCH

ROW

COLUMN

BURST COUNTER

ADDRESS BUFFER

512

9

ROW DECODER ROW DECODER

SENSE AMP I/O GATE

256x16

COLUMN DECODER

8

256x16

SENSE AMP I/O GATE

MEMORY CELL

ARRAY

BANK 1

DATA I N

BUFFER

16

DATA OUT

BUFFER

16 16

16

I/O 0-15

Vcc/VccQ
GND/GNDQ

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Rev. A

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3

IS42S16128 ISSI

®

ABSOLUTE MAXIMUM RATINGS

(1)

Symbol Parameters Rating Unit

VCC MAX Maximum Supply Voltage –1.0 to +4.6 V
VccQ

MAX Maximum Supply Voltage for Output Buffer –1.0 to +4.6 V

VIN Input Voltage –1.0 to +5.5 V
VOUT Output Voltage –1.0 to +4.6 V
PD MAX Allowable Power Dissipation 1 W
ICS Output Shorted Current 50 mA
TOPR Operating Temperature 0 to +70 °C
TSTG Storage Temperature –55 to +150 °C

DC RECOMMENDED OPERATING CONDITIONS

At TA = 0 to +70°C

Symbol Parameter Min. Typ. Max. Unit

VCC, VCCQ Supply Voltage 3.0 3.3 3.6 V

VIH Input High Voltage 2.0 — 5.5 V
VIL Input Low Voltage –0.3 — +0.8 V

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.

2. All voltages are referenced to GND.

IH (max) = 5.5V for pulse width - 5 ns.

3. V

3. VIL (min) = –1.0V for pulse width - 5 ns.

(2)

CAPACITANCE CHARACTERISTICS

At TA = 0 to +25°C, Vcc = VccQ = 3.3 ± 0.3V, f = 1 MHz

Symbol Parameter Typ. Max. Unit

CIN1 Input Capacitance: A0-A9 — 5pF
CIN2 Input Capacitance: (CLK, CKE, CS, RAS, CAS, WE, LDQM, UDQM) — 5pF
CI/O Data Input/Output Capacitance: I/O0-I/O15 — 7pF

4

(1,2)

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

Rev. A

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IS42S16128 ISSI

DC ELECTRICAL CHARACTERISTICS

(Recommended Operation Conditions unless otherwise noted.)

Symbol Parameter Test Condition Speed Min. Max. Unit

I

IL Input Leakage Current 0V ≤ VIN ≤ VCC, with pins other than –10 10 µA

the tested pin at 0V

IOL Output Leakage Current Output is disabled –10 10 µA

0V ≤ VOUT ≤ VCC
VOH Output High Voltage Level IOUT = –2 mA 2.4 — V
VOL Output Low Voltage Level IOUT = +2 mA — 0.4 V

ICC1 Operating Current

CC2P Precharge Standby Current CKE ≤ VIL (MAX)tCK = tCK (MIN) —— 3mA

I
ICC2PS (In Power-Down Mode) tCK = ×——2mA

I

CC2N Precharge Standby Current CKE ≥ VIH (MIN)tCK = tCK (MIN) ——30 mA

ICC2NS (In Non Power-Down Mode) tCK = ×——15 mA
ICC3P Active Standby Current CKE ≤ VIL (MAX)tCK = tCK (MIN) —— 3mA

ICC3PS (In Power-Down Mode) tCK = ×——2mA
ICC3N Active Standby Current CKE ≥ VIH (MIN)tCK = tCK (MIN) ——30 mA

ICC3NS (In Non Power-Down Mode) tCK = ×——15 mA
ICC4 Operating Current tCK = tCK (MIN) CAS latency = 3 -8 — 160 mA

(In Burst Mode)

ICC5 Auto-Refresh Current tRC = tRC (MIN)-8— 100 mA

ICC6 Self-Refresh Current CKE ≤ 0.2V —— 2mA

Notes:

1. These are the values at the minimum cycle time. Since the currents are transient, these values decrease as the cycle time increases.
Also note that a bypass capacitor of at least 0.01 µF should be inserted between Vcc and GND for each memory chip to suppress
power supply voltage noise (voltage drops) due to these transient currents.

2. Icc1 and Icc4 depend on the output load. The maximum values for Icc1 and Icc4 are obtained with the output open state.

(1,2)

One Bank Operation, Burst Length=1 — 100 mA
tRC ≥ tRC (min.), IOUT = 0mA

(1)

IOUT = 0mA -10 — 160 mA

-12 — 120 mA

CAS latency = 2 -8 — 120 mA

-10 — 120 mA

-12 — 110 mA

-10 — 100 mA

-12 — 80 mA

®

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

Rev. A

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5

IS42S16128 ISSI

®

AC CHARACTERISTICS

(1,2,3)

-8 -10 -12

Symbol Parameter Min. Max. Min. Max. Min. Max. Units

CK3 Clock Cycle Time CAS Latency = 3 8 — 10 — 12 — ns

t
tCK2 CAS Latency = 2 13 — 15 — 17 — ns

t

AC3 Access Time From CLK

(4)

CAS Latency = 3 — 6 — 8 — 10 ns

tAC2 CAS Latency = 2 — 10 — 13 — 15 ns
tCHI CLK HIGH Level Width 3 — 4 — 4.5 — ns
tCL CLK LOW Level Width 3 — 4 — 4.5 — ns
t

OH3 Output Data Hold Time CAS Latency = 3 3 — 4 — 4 — ns

tOH2 CAS Latency = 2 3 — 4 — 4 — ns
tLZ Output LOW Impedance Time 0 — 0 — 0 — ns

HZ3 Output HIGH Impedance Time

t

(5)

CAS Latency = 3 3648410ns

tHZ2 CAS Latency = 2 3 10 4 12 4 14 ns
tDS Input Data Setup Time 2 — 3 — 3 — ns
tDH Input Data Hold Time 1 — 1.5 — 2 — ns
tAS Address Setup Time 2 — 3 — 3 — ns
tAH Address Hold Time 1 — 1.5 — 2 — ns
tCKS CKE Setup Time 2 — 3 — 3 — ns
tCKH CKE Hold Time 1 — 1.5 — 2 — ns
tCKA CKE to CLK Recovery Delay Time 1CLK+3 — 1CLK+3 — 1CLK+3 — ns
tCS Command Setup Time (CS, RAS, CAS, WE, DQM) 2 — 3 — 3 — ns
tCH Command Hold Time (CS, RAS, CAS, WE, DQM) 1 — 1.5 — 2 — ns
tRC Command Period (REF to REF / ACT to ACT) 80 — 90 — 108 — ns
tRAS Command Period (ACT to PRE) 54 12,000 60 12,000 72 12,000 ns
tRP Command Period (PRE to ACT) 24 — 30 — 34 — ns
tRCD Active Command To Read / Write Command Delay Time 24 — 30 — 34 — ns
tRRD Command Period (ACT [0] to ACT[1]) 24 — 30 — 34 — ns
tDPL3 Input Data To Precharge CAS Latency = 3 1CLK+8 — 1CLK+10 — 1CLK+12 — ns

Command Delay time

tDPL2 CAS Latency = 2 8 — 10 — 12 — ns
tDAL3 Input Data To Active / Refresh CAS Latency = 3 2CLK+24 — 2CLK+30 — 2CLK+34 — ns

Command Delay time (During Auto-Precharge)

tDAL2 CAS Latency = 2 1CLK+24 — 1CLK+30 — 1CLK+34 — ns
tT Transition Time 1 30 1 30 1 30 ns
tREF Refresh Cycle Time — 16 — 16 — 16 ms

Notes:

1. When power is first applied, memory operation should be started 100 µs after Vcc and VccQ reach their stipulated voltages. Also
note that the power-on sequence must be executed before starting memory operation.

2. Measured with t

3. The reference level is 1.4 V when measuring input signal timing. Rise and fall times are measured between V

4. Access time is measured at 1.4V with the load shown in the figure below.

5. The time t
when the output is in the high impedance state.

6

T = 1 ns.

IH (min.) and VIL (max.).

HZ (max.) is defined as the time required for the output voltage to transition by ± 200 mV from VOH (min.) or VOL (max.)

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

Rev. A

03/13/00

IS42S16128 ISSI

OPERATING FREQUENCY / LATENCY RELATIONSHIPS

-8 -10 -12

Symbol Parameter Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Units

— Clock Cycle Time 8 10 25 10 15 30 12 17 34 ns
— Operating Frequency 125 100 40 100 65 33 83 58 29 MHz

tCAC CAS Latency 3 2 1 3 2 1 3 2 1 cycle
tRCD Active Command To Read/Write Command Delay Time 3 2 1 3 2 1 3 2 1 cycle
tRAC RAS Latency (tRCD + tCAC) 6 4 2 6 4 2 6 4 2 cycle
tRC Command Period (REF to REF / ACT to ACT) 9 5 2 9 6 3 9 7 4 cycle
tRAS Command Period (ACT to PRE) 6 3 1 6 4 2 6 5 3 cycle
tRP Command Period (PRE to ACT) 3 2 1 3 2 1 3 2 1 cycle
tRRD Command Period (ACT[0] to ACT [1]) 3 2 1 3 2 1 3 2 1 cycle

CCD Column Command Delay Time 1 1 1 1 1 1 1 1 1 cycle

t

(READ, READA, WRIT, WRITA)
tDPL Input Data To Precharge Command Delay Time 1 1 1 1 1 1 1 1 1 cycle
tDAL Input Data To Active/Refresh Command Delay Time 4 3 2 4 3 2 4 3 2 cycle

(During Auto-Precharge)
tRBD Burst Stop Command To Output in HIGH-Z Delay Time 3 2 1 3 2 1 3 2 1 cycle

(Read)
tWBD Burst Stop Command To Input in Invalid Delay Time 0 0 0 0 0 0 0 0 0 cycle

(Write)
tRQL Precharge Command To Output in HIGH-Z Delay Time 3 2 1 3 2 1 3 2 1 cycle

(Read)
tWDL Precharge Command To Input in Invalid Delay Time 0 0 0 0 0 0 0 0 0 cycle

(Write)
tPQL Last Output To Auto-Precharge Start Time (Read) –2 –10 –2 –10 –2 –1 0 cycle
tQMD DQM To Output Delay Time (Read) 2 2 2 2 2 2 2 2 2 cycle
tDMD DQM To Input Delay Time (Write) 0 0 0 0 0 0 0 0 0 cycle
tMCD Mode Register Set To Command Delay Time 2 2 2 2 2 2 2 2 2 cycle

®

AC TEST CONDITIONS (Input/Output Reference Level: 1.4V)

t

Input

2.0V

1.4V

CLK

INPUT

OUTPUT

0.8V

2.0V

1.4V

0.8V

t

CS

t

OH

1.4V 1.4V

Output Load

I/O

50 pF

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

Rev. A

03/13/00

CK

t

CHI

t

CH

t

AC

500 Ω

t

CL

+1.4V

7

IS42S16128 ISSI

COMMANDS

Active Command Read Command

®

CLK

CKE

CS

RAS

CAS

WE

A0-A7

CLK

CKE

CS

RAS

CLK

HIGH

ROW

A8

A9

ROW

BANK 1

BANK 0

CKE

CS

RAS

CAS

WE

A0-A7

HIGH

COLUMN

AUTO PRECHARGE

A8

A9

NO PRECHARGE

BANK 1

BANK 0

Write Command Precharge Command

CLK

HIGH

CKE

CS

RAS

HIGH

CAS

WE

A0-A7

A8

A9

COLUMN

AUTO PRECHARGE

BANK 1

BANK 0

CAS

WE

A0-A7

A8

A9

BANK 0 AND BANK 1

BANK 0 OR BANK 1NO PRECHARGE

BANK 1

BANK 0

No-Operation Command Device Deselect Command

CLK

CKE

CS

RAS

CAS

WE

A0-A7

A8

HIGH

CLK

CKE

CS

RAS

CAS

WE

A0-A7

HIGH

A8

A9

8

A9

Don't Care

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IS42S16128 ISSI

COMMANDS (cont.)

Mode Register Set Command Auto-Refresh Command

®

CLK

CKE

CS

RAS

CAS

WE

A0-A7

A8

A9

HIGH

OP-CODE

OP-CODE

OP-CODE

CLK

CKE

CS

RAS

CAS

WE

A0-A7

A8

A9

HIGH

Self-Refresh Command Power Down Command

CLK

CKE

CS

RAS

CLK

CKE

CS

RAS

ALL BANKS IDLE

NOP

NOP

CAS

WE

A0-A7

CAS

WE

A0-A7

A8

A9

A8

A9

NOP

NOP

Clock Suspend Command Burst Stop Command

CLK

CKE

CS

RAS

CAS

WE

A0-A7

A8

BANK(S) ACTIVE

NOP

NOP

NOP

NOP

CLK

CKE

CS

RAS

CAS

WE

A0-A7

HIGH

A8

A9

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

Rev. A

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A9

Don't Care

9

IS42S16128 ISSI

®

Mode Register Set Command

(CS, RAS, CAS, WE = LOW)
The IS42S16128 product incorporates a register that

defines the device operating mode. This command func­tions as a data input pin that loads this register from the
pins A0 to A9. When power is first applied, the stipulated
power-on sequence should be executed and then the
IS42S16128 should be initialized by executing a mode
register set command.

Note that the mode register set command can be ex­ecuted only when both banks are in the idle state, i.e..,
deactivated.

Another command cannot be executed after a mode
register set command until after the passage of the period
tMCD, which is the period required for mode register set
command execution.

Active Command

(CS, RAS = LOW, CAS, WE= HIGH)
The IS42S16128 includes two banks of 512 rows each.

This command selects one of the two banks according to
the A9 pin and activates the row selected by the pins A0
to A8.

Read Command (cont.)

When the A8 pin is HIGH, this command functions as a
read with auto-precharge command. After the burst read
completes, the bank selected by pin A9 is precharged.
When the A8 pin is LOW, the bank selected by the A9 pin
remains in the activated state after the burst read com­pletes.

Write Command

(CS, CAS, WE = LOW, RAS = HIGH)
When burst write mode has been selected with the mode

register set command, this command selects the bank
specified by the A9 pin and starts a burst write operation
at the start address specified by pins A0 to A7. This first
data must be input to the I/O pins in the cycle in which this
command.

The selected bank must be activated before executing
this command.

When A8 pin is HIGH, this command functions as a write
with auto-precharge command. After the burst write com­pletes, the bank selected by pin A9 is precharged. When
the A8 pin is low, the bank selected by the A9 pin remains
in the activated state after the burst write completes.

This command corresponds to the fall of the RAS signal
from HIGH to LOW in conventional DRAMs.

Precharge Command

(CS, RAS, WE = LOW, CAS = HIGH)
This command starts precharging the bank selected by

pins A8 and A9. When A8 is HIGH, both banks are
precharged at the same time. When A8 is LOW, the bank
selected by A9 is precharged. After executing this com­mand, the next command for the selected bank(s) is
executed after passage of the period tRP, which is the
period required for bank precharging.

This command corresponds to the RAS signal from LOW
to HIGH in conventional DRAMs

Read Command

(CS, CAS = LOW, RAS, WE = HIGH)
This command selects the bank specified by the A9 pin

and starts a burst read operation at the start address
specified by pins A0 to A7. Data is output following CAS
latency.

After the input of the last burst write data, the application
must wait for the write recovery period (t
elapse according to CAS latency.

DPL, tDAL) to

Auto-Refresh Command

(CS, RAS, CAS = LOW, WE, CKE = HIGH)
This command executes the auto-refresh operation. The

row address and bank to be refreshed are automatically
generated during this operation.

Both banks must be placed in the idle state before
executing this command.

The stipulated period (tRC) is required for a single refresh
operation, and no other commands can be executed
during this period.

The device goes to the idle state after the internal refresh
operation completes.

This command must be executed at least 1024 times
every 16 ms.

This command corresponds to CBR auto-refresh in con­ventional DRAMs.

The selected bank must be activated before executing
this command.

10

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IS42S16128 ISSI

®

Self-Refresh Command

(CS, RAS, CAS, CKE = LOW, WE = HIGH)
This command executes the self-refresh operation. The

row address to be refreshed, the bank, and the refresh
interval are generated automatically internally during this
operation. The self-refresh operation is started by drop­ping the CKE pin from HIGH to LOW. The self-refresh
operation continues as long as the CKE pin remains LOW
and there is no need for external control of any other pins.
The self-refresh operation is terminated by raising the
CKE pin from LOW to HIGH. The next command cannot
be executed until the device internal recovery period (tRC)
has elapsed. After the self-refresh, since it is impossible
to determine the address of the last row to be refreshed,
an auto-refresh should immediately be performed for all
addresses (1024 cycles).

Both banks must be placed in the idle state before
executing this command.

Burst Stop Command

(CS, WE, = LOW, RAS, CAS = HIGH)
The command forcibly terminates burst read and write

operations. When this command is executed during a
burst read operation, data output stops after the CAS
latency period has elapsed.

Power-Down Command (cont.)

All pins other than the CKE pin are invalid and none of the
other commands can be executed in this mode. The
power-down operation is terminated by raising the CKE
pin from LOW to HIGH. The next command cannot be
executed until the recovery period (tCKA) has elapsed.

Since this command differs from the self-refresh com­mand described above in that the refresh operation is not
performed automatically internally, the refresh operation
must be performed within the refresh period (tREF). Thus
the maximum time that power-down mode can be held is
just under the refresh cycle time.

Clock Suspend

(CKE = LOW)
This command can be used to stop the device internal

clock temporarily during a read or write cycle. Clock
suspend mode is started by dropping the CKE pin from
HIGH to LOW. Clock suspend mode continues as long as
the CKE pin is held LOW. All input pins other than the CKE
pin are invalid and none of the other commands can be
executed in this mode. Also note that the device internal
state is maintained. Clock suspend mode is terminated by
raising the CKE pin from LOW to HIGH, at which point
device operation restarts. The next command cannot be
executed until the recovery period (tCKA) has elapsed.

No Operation

(CS, = LOW, RAS, CAS, WE = HIGH)
This command has no effect on the device.

Device Deselect Command

(CS = HIGH)
This command does not select the device for an object of

operation. In other words, it performs no operation with
respect to the device.

Power-Down Command

(CKE = LOW)
When both banks are in the idle (inactive) state, or when

at least one of the banks is not in the idle (inactive) state,
this command can be used to suppress device power
dissipation by reducing device internal operations to the
absolute minimum. Power-down mode is started by drop­ping the CKE pin from HIGH to LOW. Power-down mode
continues as long as the CKE pin is held low.

Since this command differs from the self-refresh com­mand described above in that the refresh operation is not
performed automatically internally, the refresh operation
must be performed within the refresh period (tREF). Thus
the maximum time that clock suspend mode can be held
is just under the refresh cycle time.

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

Rev. A

03/13/00

11

IS42S16128 ISSI

®

COMMAND TRUTH TABLE

(1,2)

CKE

Symbol Command n-1 n CS RAS CAS W E DQM A0 A8 A7-A0 I/On

(5)

(5,6)

(3,4)

HXLLLLX OP CODE X
H H L L L H X X X X HIGH-Z
HLLLLHXX X XHIGH-Z

MRS Mode Register Set
REF Auto-Refresh
SREF Self-Refresh
PRE Precharge Selected Bank H X L L H L X BS L X X
PALL Precharge Both Banks H X L L H L X X H X X
ACT Bank Activate

(7)

H X L L H H X BS Row Row X
WRIT Write H X L H L L X BS L Column X
WRITA Write With Auto-Precharge
READ Read

(8)

READA Read With Auto-Precharge
BST Burst Stop

(9)

(8)

H X L H L L X BS H Column X

H X L H L H X BS L Column X

(8)

H X L H L H X BS H Column X

HXLHHLXXXX X
NOP No Operation H X L H H H X X X X X
DESL Device Deselect H X H XXXXX X X X
SBY Clock Suspend / Standby Mode L XXXXXXX X X X
ENB Data Write / Output Enable H XXXXXLX X X Active
MASK Data Mask / Output Disable H XXXXXHX X XHIGH-Z

DQM TRUTH TABLE

(1,2)

CKE DQM

Symbol Command n-1 n UPPER LOWER

ENB Data Write / Output Enable H X L L
MASK Data Mask / Output Disable H X H H
ENBU Upper Byte Data Write / Output Enable H X L X
ENBL Lower Byte Data Write / Output Enable H X X L
MASKU Upper Byte Data Mask / Output Disable H X H X
MASKL Lower Byte Data Mask / Output Disable H X X H

CKE TRUTH TABLE

(1,2)

CKE

Symbol Command Current State n-1 n CS RAS CAS WE A9 A8 A7-A0

SPND Start Clock Suspend Mode Active H L XXXXXXX

— Clock Suspend Other States L L XXXXXXX
— Terminate Clock Suspend Mode Clock Suspend L H XXXXXXX

REF Auto-Refresh Idle H H L L L H X X X
SELF Start Self-Refresh Mode Idle H LLLLHXXX
SELFX Terminate Self-Refresh Mode Self-Refresh L H L H H H X X X

LHHXXXXXX

PDWN Start Power-Down Mode Idle H L L H H H X X X

HLHXXXXXX

— Terminate Power-Down Mode Power-Down L H XXXXXXX

12

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IS42S16128 ISSI

®

OPERATION COMMAND TABLE

(1,2)

Current State Command Operation CS RAS CAS W E A9 A8 A7-A0

Idle DESL No Operation or Power-Down

NOP No Operation or Power-Down

(12)

(12)

HXXXXXX

LHHHXXX
BST No Operation or Power-Down L H H L X X X
READ / READA Illegal L H L H V V V
WRIT/WRITA Illegal L H L L V V V
ACT Row Active L L H H V V V
PRE/PALL No Operation L L H L V V X
REF/SELF Auto-Refresh or Self-Refresh

(13)

LLLHXXX
MRS Mode Register Set LLLL OP CODE

Row Active DESL No Operation H XXXXXX

NOP No Operation L H H H X X X
BST No Operation L H H L X X X

(10)

(17)

(17)

(15)

LHLHVVV

LHL LVVV

LLHHVVV

LLHLVVX

READ/READA Read Start
WRIT/WRITA Write Start
ACT Illegal
PRE/PALL Precharge
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Read DESL Burst Read Continues, Row Active When Done H XXXXXX

NOP Burst Read Continues, Row Active When Done L H H H X X X
BST Burst Interrupted, Row Active After Interrupt L H H L X X X

(11,16)

(16)

LHLHVVV

LHL LVVV

LLHHVVV

READ/READA Burst Interrupted, Read Restart After Interrupt
WRIT/WRITA Burst Interrupted Write Start After Interrupt
ACT Illegal

(10)

PRE/PALL Burst Read Interrupted, Precharge After Interrupt L L H L V V X
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Write DESL Burst Write Continues, Write Recovery When Done H XXXXXX

NOP Burst Write Continues, Write Recovery When Done L H H H X X X
BST Burst Write Interrupted, Row Active After Interrupt L H H L X X X
READ/READA
WRIT/WRITA

Burst Write Interrupted, Read Start After Interrupt
Burst Write Interrupted, Write Restart After Interrupt

ACT Illegal

(10)

(11,16)

(16)

LHLHVVV

LHL LVVV

LLHHVVV
PRE/PALL Burst Write Interrupted, Precharge After Interrupt L L H L V V X
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Read With DESL Burst Read Continues, Precharge When Done H XXXXXX
Auto- NOP Burst Read Continues, Precharge When Done L H H H X X X

Precharge BST Illegal L H H L X X X

READ/READA Illegal L H L H V V V
WRIT/WRITA Illegal L H L L V V V
ACT Illegal
PRE/PALL Illegal

(10)

(10)

LLHHVVV

LLHLVVX
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

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13

IS42S16128 ISSI

®

OPERATION COMMAND TABLE

(1,2)

Current State Command Operation CS RAS CAS W E A9 A8 A7-A0

Write With DESL Burst Write Continues, Write Recovery And Precharge H XXXXXX
Auto-Precharge When Done

NOP Burst Write Continues, Write Recovery And Precharge L H H H X X X
BST Illegal L H H L X X X
READ/READA Illegal L H L H V V V
WRIT/WRITA Illegal L H L L V V V
ACT Illegal
PRE/PALL Illegal

(10)

(10)

LLHHVVV

LLHLVVX
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OPCODE

Row Precharge DESL No Operation, Idle State After tRP Has Elapsed H XXXXXX

NOP No Operation, Idle State After t
BST No Operation, Idle State After t
READ/READA Illegal
WRIT/WRITA Illegal
ACT Illegal

(10)

(10)

(10)

PRE/PALL No Operation, Idle State After tRP Has Elapsed

RP Has Elapsed L H H H X X X
RP Has Elapsed L H H L X X X

LHLHVVV

LHL LVVV

LLHHVVV

(10)

LLHLVVX
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Immediately DESL No Operation, Row Active After tRCD Has Elapsed H XXXXXX
Following NOP No Operation, Row Active After tRCD Has Elapsed L H H H X X X

Row Active BST No Operation, Row Active After tRCD Has Elapsed L H H L X X X

READ/READA Illegal
WRIT/WRITA Illegal
ACT Illegal
PRE/PALL Illegal

(10)

(10)

(10,14)

(10)

LHLHVVV

LHL LVVV

LLHHVVV

LLHLVVX
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Write DESL No Operation, Row Active After tDPL Has Elapsed H XXXXXX
Recovery NOP No Operation, Row Active After tDPL Has Elapsed L H H H X X X

BST No Operation, Row Active After tDPL Has Elapsed L H H L X X X
READ/READA Read Start L H L H V V V
WRIT/WRITA Write Restart L H L L V V V
ACT Illegal
PRE/PALL Illegal

(10)

(10)

LLHHVVV

LLHLVVX
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

14

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IS42S16128 ISSI

®

OPERATION COMMAND TABLE

(1,2)

Current State Command Operation CS RAS CAS W E A9 A8 A7-A0

Write Recovery DESL No Operation, Idle State After tDAL Has Elapsed H XXXXXX
With Auto- NOP No Operation, Idle State After tDAL Has Elapsed L H H H X X X

Precharge BST No Operation, Idle State After t

READ/READA Illegal
WRIT/WRITA Illegal
ACT Illegal
PRE/PALL Illegal

(10)

(10)

(10)

(10)

DAL Has Elapsed L H H L X X X

LHLHVVV
LHL LVVV
LLHHVVV

LLHLVVX
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Refresh DESL No Operation, Idle State After t

RP Has Elapsed H XXXXXX

NOP No Operation, Idle State After tRP Has Elapsed L H H H X X X
BST No Operation, Idle State After t

RP Has Elapsed L H H L X X X

READ/READA Illegal L H L H V V V
WRIT/WRITA Illegal L H L L V V V
ACT Illegal L L H H V V V
PRE/PALL Illegal L L H L V V X
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Mode Register DESL No Operation, Idle State After tMCD Has Elapsed H XXXXXX
Set NOP No Operation, Idle State After tMCD Has Elapsed L H H H X X X

BST No Operation, Idle State After tMCD Has Elapsed L H H L X X X
READ/READA Illegal L H L H V V V
WRIT/WRITA Illegal L H L L V V V
ACT Illegal L L H H V V V
PRE/PALL Illegal L L H L V V X
REF/SELF Illegal L L L H X X X
MRS Illegal LLLL OP CODE

Notes:

1. H: HIGH level input, L: LOW level input, X: HIGH or LOW level input, V: Valid data input

2. All input signals are latched on the rising edge of the CLK signal.

3. Both banks must be placed in the inactive (idle) state in advance.

4. The state of the A0 to A9 pins is loaded into the mode register as an OP code.

5. The row address is generated automatically internally at this time. The I/O pin and the address pin data is ignored.

6. During a self-refresh operation, all pin data (states) other than CKE is ignored.

7. The selected bank must be placed in the inactive (idle) state in advance.

8. The selected bank must be placed in the active state in advance.

9. This command is valid only when the burst length set to full page.

10. This is possible depending on the state of the bank selected by the A9 pin.

11. Time to switch internal busses is required.

12. The IS42S16128 can be switched to power-down mode by dropping the CKE pin LOW when both banks in the idle state. Input
pins other than CKE are ignored at this time.

13. The IS42S16128 can be switched to self-refresh mode by dropping the CKE pin LOW when both banks in the idle state. Input
pins other than CKE are ignored at this time.

14. Possible if t

15. Illegal if tRAS is not satisfied.

16. The conditions for burst interruption must be observed. Also note that the IS42S16128 will enter the precharged state
immediately after the burst operation completes if auto-precharge is selected.

17. Command input becomes possible after the period t
state immediately after the burst operation completes if auto-precharge is selected.

RRD is satisfied.

RCD has elapsed. Also note that the IS42S16128 will enter the precharged

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

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15

IS42S16128 ISSI

®

CKE RELATED COMMAND TRUTH TABLE

(1)

CKE

Current State Operation n-1 n CS RAS CAS W E A9 A8 A7-A0

Self-Refresh Undefined H XXXXXXXX

Self-Refresh Recovery
Self-Refresh Recovery

(2)

Illegal

(2)

Illegal

(2)

(2)

LHHXXXXXX
LHLHHXXXX
LHLHLXXXX
LHL LXXXXX

Self-Refresh L L XXXXXXX

Self-Refresh Recovery Idle State After tRC Has Elapsed H H H XXXXXX

Idle State After t

RC Has Elapsed H H L H H XXXX

Illegal H H L H L XXXX
Illegal H H L L XXXXX
Power-Down on the Next Cycle H L H XXXXXX
Power-Down on the Next Cycle H L L H H XXXX
Illegal H L L H L XXXX
Illegal H L L L XXXXX
Clock Suspend Termination on the Next Cycle

(2)

LHXXXXXXX

Clock Suspend L L XXXXXXX

Power-Down Undefined H XXXXXXXX

Power-Down Mode Termination, Idle After L H XXXXXXX
That Termination

(2)

Power-Down Mode L L XXXXXXX

Both Banks Idle No Operation H H H XXXXXX

See the Operation Command Table H H L H XXXXX
Bank Active Or Precharge H H L L H XXXX
Auto-Refresh H H L L L H X X X
Mode Register Set H H LLLL OP CODE
See the Operation Command Table H L H XXXXXX
See the Operation Command Table H L L H XXXXX
See the Operation Command Table H L L L H XXXX
Self-Refresh

(3)

HLLLLHXXX
See the Operation Command Table H LLLLL OP CODE
Power-Down Mode

(3)

LXXXXXXXX

Other States See the Operation Command Table H H XXXXXXX

Clock Suspend on the Next Cycle

(4)

HLXXXXXXX
Clock Suspend Termination on the Next Cycle L H XXXXXXX
Clock Suspend Termination on the Next Cycle L L XXXXXXX

Notes:

1. H: HIGH level input, L: LOW level input, X: HIGH or LOW level input

2. The CLK pin and the other input are reactivated asynchronously by the transition of the CKE level from LOW to HIGH. The
minimum setup time (t

3. Both banks must be set to the inactive (idle) state in advance to switch to power-down mode or self-refresh mode.

4. The input must be command defined in the operation command table.

CKA) required before all commands other than mode termination must be satisfied.

16

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IS42S16128 ISSI

®

TWO BANKS OPERATION COMMAND TRUTH TABLE

(1,2)

Previous State Next State

Operation CS RAS CAS WE A9 A8 A7-A0 BANK 0 BANK 1 BANK 0 BANK 1

DESL H XXXXXX Any Any Any Any
NOP L H H H X X X Any Any Any Any
BST L H H L X X X R/W/A I/A A I/A

I I/A I I/A
I/A R/W/A I/A A
I/A I I/A I

READ/READA L H L H H H CA I/A R/W/A I/A RP

H H CA R/W A A RP
H L CA I/A R/W/A I/A R
H L CA R/W A A R
L H CA R/W/A I/A RP I/A
L H CA A R/W RP A
L L CA R/W/A I/A R I/A
L L CA A R/W R A

WRIT/WRITA L H L L H H CA I/A R/W/A I/A WP

H H CA R/W A A WP
H L CA I/A R/W/A I/A W
H L CA R/W A A W
L H CA R/W/A I/A WP I/A
L H CA A R/W WP A
L L CA R/W/A I/A W I/A
L L CA A R/W W A

ACT L L H H H RA RA Any I Any A

L RA RA I Any A Any

PRE/PALL L L H L X H X R/W/A/I I/A I I

X H X I/A R/W/A/I I I
H L X I/A R/W/A/I I/A I
H L X R/W/A/I I/A R/W/A/I I
L L X R/W/A/I I/A I I/A

L L X I/A R/W/A/I I R/W/A/I
REF LLLHXXX II II
MRS LLLL OPCODE I I I I

Notes:

1. H: HIGH level input, L: LOW level input, X: HIGH or LOW level input, RA: Row Address, CA: Column Address

2. The device state symbols are interpreted as follows:

I Idle (inactive state)
A Row Active State
R Read
W Write
RP Read With Auto-Precharge
WP Write With Auto-Precharge
Any Any State

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17

IS42S16128 ISSI

SIMPLIFIED STATE TRANSITION DIAGRAM (One Bank Operation)

SELF

REFRESH

SREF entry

SREF exit

®

WRIT

CKE_

MODE

REGISTER

MRS

IDLE

REF

SET

CKE_

CKE

ACT

CKE_

CKE

READ

BANK

ACTIVE

READ

READA

BST BST

WRIT

WRITA

WRITE

WRIT

AUTO

REFRESH

IDLE

POWER

DOWN

ACTIVE
POWER

DOWN

READ

READ

CKE_

18

CLOCK

SUSPEND

POWER APPLIED

CKE

WRITA

CKE_

CKE

WRITE WITH

AUTO

PRECHARGE

POWER ON

Automatic transition following the
completion of command execution.

Transition due to command input.

WRITA

PRE

PRE

PRE

PRE-

CHARGE

READA

PRE

READA

CKE_

READ WITH

AUTO

PRECHARGE

CKE

CKE

CLOCK

SUSPEND

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IS42S16128 ISSI

®

Device Initialization At Power-On

(Power-On Sequence)

As is the case with conventional DRAMs, the IS42S16128
product must be initialized by executing a stipulated
power-on sequence after power is applied.

After power is applied and V
stipulated voltages, set and hold the CKE and DQM pins
HIGH for 100 µs. Then, execute the precharge command
to precharge both bank. Next, execute the auto-refresh
command twice or more and define the device operation
mode by executing a mode register set command.

The mode register set command can be also set before
auto-refresh command.

CC and VCCQ reach their

Mode Register Settings

The mode register set command sets the mode register.
When this command is executed, pins A0 to A7, A8, and
A9 function as data input pins for setting the register, and
this data becomes the device internal OP code. This OP
code has four fields as listed in the table below.

Input Pin Field

Burst Length

When writing or reading, data can be input or output data
continuously. In these operations, an address is input only
once and that address is taken as the starting address
internally by the device. The device then automatically
generates the following address. The burst length field in
the mode register stipulates the number of data items
input or output in sequence. In the IS42S16128 product,
a burst length of 1, 2, 4, 8, or full page can be specified.
See the table on the next page for details on setting the
mode register.

Burst Type

The burst data order during a read or write operation is
stipulated by the burst type, which can be set by the mode
register set command. The IS42S16128 product supports
sequential mode and interleaved mode burst type set­tings. See the table on the next page for details on setting
the mode register. See the "Burst Length and Column
Address Sequence" item for details on I/O data orders in
these modes.

A9, A8, A7 Write Mode
A6, A5, A4 CAS Latency

A3 Burst Type

A2, A1, A0 Burst Length

Note that the mode register set command can be ex­ecuted only when both banks are in the idle (inactive)
state. Wait at least two cycles after executing a mode
register set command before executing the next com­mand.

CAS Latency

During a read operation, the between the execution of the
read command and data output is stipulated as the CAS
latency. This period can be set using the mode register
set command. The optimal CAS latency is determined by
the clock frequency and device speed grade. See the
"Operating Frequency / Latency Relationships" item for
details on the relationship between the clock frequency
and the CAS latency. See the table on the next page for
details on setting the mode register.

Write Mode

Burst write or single write mode is selected by the OP code
(A9, A8, A7) of the mode register.

A burst write operation is enabled by setting the OP code
(A9, A8, A7) to (0,0,0). A burst write starts on the same
cycle as a write command set. The write start address is
specified by the column address and bank select address
at the write command set cycle.

A single write operation is enabled by setting OP code
(A9, A8, A7) to (1,0,0). In a single write operation, data is
only written to the column address and bank select
address specified by the write command set cycle without
regard to the bust length setting.

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19

IS42S16128 ISSI

MODE REGISTER

®

9876543210

WRITE MODE LT MODE BT BL

Address Bus
Mode Register (Mx)

Burst Type 0 Sequential

Latency Mode 0 0 0 Reserved

M2 M1 M0 Sequential Interleaved

Burst Length 0 0 0 1 1

001 2 2
010 4 4
011 8 8
1 0 0 Reserved Reserved
1 0 1 Reserved Reserved
1 1 0 Reserved Reserved
1 1 1 Full Page Reserved

M3 Type

1 Interleaved

M6 M5 M4 CAS Latency

001 1
010 2
011 3
1 0 0 Reserved
1 0 1 Reserved
1 1 0 Reserved
1 1 1 Reserved

M9 M8 M7 Write Mode

0 0 0 Burst Read & Burst Write
1 0 0 Burst Read & Single Write

20

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IS42S16128 ISSI

Burst Length and Column Address Sequence

Column Address Address Sequence

Burst Length A2 A1 A0 Sequential Interleaved

2 X X 0 0-1 0-1

X X 1 1-0 1-0

4 X 0 0 0-1-2-3 0-1-2-3

X 0 1 1-2-3-0 1-0-3-2
X 1 0 2-3-0-1 2-3-0-1
X 1 1 3-0-1-2 3-2-1-0

8 0 0 0 0-1-2-3-4-5-6-7 0-1-2-3-4-5-6-7

0 0 1 1-2-3-4-5-6-7-0 1-0-3-2-5-4-7-6
0 1 0 2-3-4-5-6-7-0-1 2-3-0-1-6-7-4-5
0 1 1 3-4-5-6-7-0-1-2 3-2-1-0-7-6-5-4
1 0 0 4-5-6-7-0-1-2-3 4-5-6-7-0-1-2-3
1 0 1 5-6-7-0-1-2-3-4 5-4-7-6-1-0-3-2
1 1 0 6-7-0-1-2-3-4-5 6-7-4-5-2-3-0-1
1 1 1 7-0-1-2-3-4-5-6 7-6-5-4-3-2-1-0

Full Page n n n Cn, Cn+1, Cn+2 None

(256) Cn+3, Cn+4.....

...Cn-1(Cn+255),

Cn(Cn+256).....

Notes:

1. The burst length in full page mode is 256.

®

Bank Select and Precharge Address Allocation

Row X0 — Row Address

X1 — Row Address
X2 — Row Address
X3 — Row Address
X4 — Row Address
X5 — Row Address
X6 — Row Address
X7 — Row Address
X8 0 Precharge of the Selected Bank (Precharge Command) Row Address

1 Precharge of Both Banks (Precharge Command) (Active Command)

X9 0 Bank 0 Selected (Precharge and Active Command)

1 Bank 1 Selected (Precharge and Active Command)

Column Y0 — Column Address

Y1 — Column Address
Y2 — Column Address
Y3 — Column Address
Y4 — Column Address
Y5 — Column Address
Y6 — Column Address
Y7 — Column Address
Y8 0 Auto-Precharge Not Performed

1 Auto-Precharge Performed

Y9 0 Bank 0 Selected (Read and Write Commands)

1 Bank 1 Selected (Read and Write Commands)

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21

IS42S16128 ISSI

Burst Read

®

The read cycle is started by executing the read command.
The address provided during read command execution is
used as the starting address. First, the data correspond­ing to this address is output in synchronization with the
clock signal after the CAS latency period. Next, data
corresponding to an address generated automatically by
the device is output in synchronization with the clock
signal.

The output buffers go to the LOW impedance state CAS
latency minus one cycle after the read command, and go
to the HIGH impedance state automatically after the last
data is output. However, the case where the burst length

CLK

COMMAND

I/O

READ

CAC

t

CAS LATENCY

CAS latency = 3, burst length = 4

D

OUT

is a full page is an exception. In this case the output
buffers must be set to the high impedance state by
executing a burst stop command.

Note that upper byte and lower byte output data can be
masked independently under control of the signals ap­plied to the U/LDQM pins. The delay period (tQMD) is fixed
at two, regardless of the CAS latency setting, when this
function is used.

The selected bank must be set to the active state before
executing this command.

0D

OUT

1D

OUT

2D

OUT

3

BURST LENGTH

Burst Write

The write cycle is started by executing the command. The
address provided during write command execution is
used as the starting address, and at the same time, data
for this address is input in synchronization with the clock
signal.

Next, data is input in other in synchronization with the
clock signal. During this operation, data is written to
address generated automatically by the device. This
cycle terminates automatically after a number of clock
cycles determined by the stipulated burst length. How­ever, the case where the burst length is a full page is an
exception. In this case the write cycle must be terminated
by executing a burst stop command.

CLK

COMMAND

I/O

WRITE

DIN 0DIN 1DIN 2DIN 3

BURST LENGTH

The latency for I/O pin data input is zero, regardless of the
CAS latency setting. However, a wait period (write recov­ery: tDPL) after the last data input is required for the device
to complete the write operation.

Note that the upper byte and lower byte input data can be
masked independently under control of the signals ap­plied to the U/LDQM pins. The delay period (tDMD) is fixed
at zero, regardless of the CAS latency setting, when this
function is used.

The selected bank must be set to the active state before
executing this command.

CAS latency = 2,3, burst length = 4

22

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IS42S16128 ISSI

Read With Auto-Precharge

®

The read with auto-precharge command first executes a
burst read operation and then puts the selected bank in
the precharged state automatically. After the precharge
completes, the bank goes to the idle state. Thus this
command performs a read command and a precharge
command in a single operation.

During this operation, the delay period (tPQL) between the
last burst data output and the start of the precharge
operation differs depending on the CAS latency setting.

When the CAS latency setting is one, the precharge
operation starts a the same time as the last burst data is
output (tPQL = 0). When the CAS latency setting is two,

CLK

the precharge operation starts on one clock cycle before
the last burst data is output (tPQL = –1). When the CAS
latency setting is three, the precharge operation starts on
two clock cycles before the last burst data is output
(tPQL = –2). Therefore, the selected bank can be made
active after a delay of tRP from the start position of this
precharge operation.

The selected bank must be set to the active state before
executing this command.

The auto-precharge function is invalid if the burst length
is set to full page.

CAS Latency 3 2

tPQL –2 –1

COMMAND

READA 0

I/O

CAS latency = 2, burst length = 4

READ WITH AUTO-PRECHARGE

(BANK 0)

CLK

COMMAND

READA 0

I/O

READ WITH AUTO-PRECHARGE

(BANK 0)

CAS latency = 3, burst length = 4

D

OUT

0D

OUT

PRECHARGE START

D

OUT

PRECHARGE START

1D

OUT

0D

OUT

t

PQL

2D

t

1D

OUT

RP

t

OUT

3

PQL

2D

t

RP

ACT 0

OUT

ACT 0

3

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

Rev. A

03/13/00

23