V54C316162V
200/183/166/143 MHz 3.3 VOLT, 4K REFRESH
ULTRA HIGH PERFORMANCE
1M X 16 SDRAM 2 BANKS X 512Kbit X 16
V54C316162V
Clock Frequency(tCK)200183166143MHz
Latency3333clocks
CycleTime(t
Access Time (t
)55.567ns
CK
)55.35.55.5ns
AC
Features
■ JEDEC S tand ard 3.3V Power Supply
■ The V54C316162V is ideally suited for high per-
formance graphics peripheral applications
■ Single Pulsed RAS
■ Programmable CAS Latency: 2, 3
■ All Inputsare sampled at the positive goingedge
of clock
■ Programmable Wrap Sequ ence: Sequential or
Interleave
Interface
-5-55-6-7Unit
Description
The V54C316162V is a 16, 777,216 bits synchronous high data rate DRAM organized as 2 x
524,288 words by 16 bits. The device is designed to
comply with JEDEC standards set for synchronous
DRAM products, both electrically and mechanically.
Synchronous design allows precise cycle control
with the system clock. The CAS latency, burst
length and burst sequence must be programm ed
into device prior to access operation.
■ Programmable Burst Length: 1, 2, 4, 8 and Full
Page for Sequential an d 1, 2, 4, 8 for Interleave
Power(+3.3V)
Ground
Power for I/O’s (+3.3V)
Ground for I/O’s
V54C316162V Rev. 2.9 September 2001
2
MOSEL VITELIC
Block Diagram
V54C316162V
CLK
CKE
CS
RAS
CAS
WE
DQMi
CLK
Address
Timing
Register
Register
Programming
DQMi
Sense Amplifier
Column Decoder
Latency 8
Burst Length
Write
Control
Logic
Memory Array
Bank 0
512k x 16
Row
Decoder
Column Address
Counter
Column Address
Buffer
A0-A7, BA
Column Addresses
MUX
Sense Amplifier
Column Decoder
Memory Array
Bank 1
512k x 16
Row
Decoder
Row Address
Buffer
A
, BA
0-A10
Row Addresses
Input
UDQM
LDQM
Output
Buffer
Buffer
Refresh
Counter
I/O
-I/O
1
V54C316162V-02
16
V54C316162V Rev.2.9 September 2001
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MOSEL VITELIC
V54C316162V
Signal Pin Description
PinNameInput Function
CLKClock InputSystemclockinput.Activeonthepositiverisingedgeto sampleallinptus
CKEClock EnableActivates the CLKsignalwhen high anddeactivates the CLKwhen low.
CKE low initiates the power down mode, suspend mode, or the self
refresh mode
CS
Chip SelectDisablesor enables device operation by maskingor enabling all inputs
except CLK, CKE and DQMi
RAS
Row A ddress StrobeLatches rowaddresseson the positive edge of CLK with RAS low.
Enablesrow access& precharge
CAS
Column Address StrobeLatches column addresses on the positive edge of CLK with CAS low.
Enablescolumn access
WE
A
0-A10
WriteEnableEnableswriteoperation
AddressDuring a bank activate command, A0-A10defines the row address.
During a read or write command, A
addition to thecolumnaddressA
define the bank to be precharged. A
duringa precharge cycle, If A
if A
is low, the BA is used to decide which bank to precharge. If A10is
10
10
defines the column address. In
0-A7
isused to invoke auto prechargeBA
10
islow, auto precharge is disabled
10
is high, both bank will be precharged ,
high, all banks willbe precharged.
BABank SelectSelectswhich bank to activate.BA low select bankA and high selects
bank B
I/O
1
-I/O
16
Data Input/OutputData inputs/output are multiplexed on the same pins
UDQM, LDQMData Input/Output MaskMakes data output Hi-Z. Blocks data input when DQM is active
VDD/VSSPower Supply/GroundPower Supply. +3.3V ± 0.3V/ground
VDDQ/VSSQData Output P ower/GroundProvidesisolatedpower/ground to DQs forimprovednoise immunity
NCNo Connection
V54C316162V Rev.2.9 September 2001
4
MOSEL VITELIC
Address Input for Mode Set (Mode Register Operation)
The default power on state of the mode register is
supplier specific and may be undefined. The
following power on and initialization sequence
guarantees the device is preconditioned to eac h
users specific needs. Like a c onv ent ional DRAM,
the Synchronous DRAM must be powered up and
initialized in a predefined manner. During power on,
all VCC and VCCQ pins m ust be built up
simultaneously to the specified vol tage when the
input signals are held in the “NOP” state. The power
on voltage must not ex c eed VCC+0.3V on any of
the input pins or VCC supplies. The CLK signal
must be s tarted at the same time. After power on,
an initial pause of 200 µs is required followed by a
precharge of both banks using the precharge
command. To prevent data contention on the DQ
bus during poweron,it is required that the DQM and
CKE pins be held high during the i nitial pause
period. Once all bank s have been precharged, the
Mode Register S et Command mus t be issued to
initialize the Mode Register. A minimum of eight
Auto Refresh cycles (CBR) are also required.These
may be done before or after prog ramm ing the Mode
Register. Failure to follow these st eps may l ead to
unpredictable start-up modes.
Programming the Mode Register
The Mode register designates the operation
mode at the read or write cycle. Th is register is divided into 4 fields. A Burst Length Field to set the
length of the burst, an Addressing Selection bit to
program the column access sequence in a burst
cycle (interleaved or sequential), a CAS Latency
Fieldtoset the access time at clockcycle and a Operation m ode field to differentiate between normal
operation (Burst read and burst Write) and a spec ial
Burst Read and Single Write mode. The mode set
operation must be done before any activate command after the initial power up. Any content of the
mode register can be altered by re-executing the
mode set command. All banks must be in precharged state and CKE must be high at least one
clock before the mode set operation. After the mode
register is set, a Standby or NOP command is
required. Low signals of RAS
positive edge of the clock activate the mode set
operation. Address input dat a at this timing defines
parameters to bes et as shown in the previous table.
,CAS, and WE at the
V54C316162V Rev. 2.9 September 2001
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MOSEL VITELIC
V54C316162V
Read and Write Operation
When RAS is low and both CAS and WE arehigh
at the positive edge of the clock, a R AS cycle starts.
According to address data, a word line of the selected bank is activated and all of sense amplifiers associated to the wordline are set. A CAS
triggered by setting RAS
high and CAS low at a
clock timing after a necessary de lay, t
RAS
timing. W E is used to define either a read
(WE
=H)orawrite(WE= L) at this stage .
SDRAM provides a wide variety of fast access
modes. In a single CAS cycle, serial data read or
write operations are allowed at up to a 166 MHz
data rat e. The numbers of s erial data bits are the
burst length programmedatth e mode set operation,
i.e., one of 1, 2, 4, 8 and full page. Column addresses are segmented by the burst length and serial
data accesses are done within this boundary. The
first column address to be accessed is supplied at
the CAS timing and the subsequent addresses are
generated automatically by the programmed burst
length and its sequence. For example, in a burst
length of 8 with interleave sequence, if th e first address is ‘2’, then the rest of the burst sequence is 3,
0, 1, 6, 7, 4, and 5.
Full page burst operation is only possible using
the sequential burst type and page le ngth is a function of the I/O organisation and column addressing.
Full page burst operation do not s elf terminate once
the burst length has been reac hed. In other words,
unlike burst length of 2, 4 or 8, full page burst c ontinues until it is te rminated using another command.
,fromthe
RCD
cycle is
Similar t o the page mode of conventional
DRAM’s, burst read or write accesses on any column address are possible once the RAS cycle
latches the sense amplifiers. The maximum t
RAS
or
ther ef res h interval time limits the number ofrandom
column access es . A new burst access can be done
even before the previous b urst ends. The interrupt
operation at every clock cycles is supported. When
the previous burst is interrupted, the remaining addresses are overridden by the new address with the
full burst length. An interrupt which acc ompanies
with an operation change from a read to a write is
possible by exploiting DQM to avoid bus contention .
When two or morebanks are activated
sequentially,interleaved bankread or write
operations are possible. With the programmed
burst length, alternate access and precharge
operations on two or more bank s can realize fas t
serial da ta access modes among many different
pages. Once two or more bank s are activated,
column to column interleave operation can b e done
between different pages.
Refresh Mode
SDRAM has two refresh modes, Aut o Refresh
and Self Refresh. AutoRefresh is similar to the CAS
-before-RAS refresh of conventional DRAMs. All of
banks must be precharged before applying any refresh mode. An on-chip address counter increments
the word and the bankaddresses and no bank information is required for both ref res h modes.
and CAS are held low and CKE and WE are
held high at a clock timing. The mode restores word
line after the refresh and no external precharge
command is nec es s ary. A minimum tRC time is required between t wo automatic refreshes in a burst
refresh mode. The same rule applies to any ac cess
command after the automatic refres h operation.
The chi p has an on-chip timer and the Self Refresh mode is available. It enters the mode when
RAS
,CAS, and CKE are low and WE is high at a
clock timing. All of external control signals including
the clock are disabled. Returning CKE to high enables the clock and initiates the refresh ex it operation. After the exit command, at least one t
RC
delay
is required prior to any access command.
DQM Function
DQM has two functions for data I/O read and
write operations. During reads, when it turns to
“high” at a clock timing, data outputs are disabled
and become high impedance after two clock delay
(DQM Data Disable Latency t
). It also provides
DQZ
a data mas k function for writes. When DQM is activated, the write operation atthe ne xt clock is prohibited (DQMWriteMaskLatencyt
= zero clocks).
DQW
DQM is used for device selection, byte selection
and bus control in a memory system. LDQM c ontrols DQ0 to DQ7, UDQM controls D Q8 to DQ15.
Suspend Mode
Duringnormalaccess mode, CKE isheld high enabling the clo ck. When CKE is low, it freezes t he internal clock and extends data read and write
operations. One clock delay is required for mode
entry a nd exit (Clock Suspend Latency t
CSL
).
Power Down
In order to reduce standby power consumption, a
power down mode is available. All banks m us t be
precharged and the necessary Precharge delay
(trp) must occur before the SDRAM can enter the
Power Down mode. Once the Power Down mode is
initiated by holding CKE low, all of the receiver circuits except CLK and CKE are gated off. The Power
Down mode does not perform any refresh operations, therefore the device can’t remain in Power
Down mode longer than the Refresh period (tref) of
the device. E x it from this mode is performed by t ak ing CKE “high”. One clock delay is required for
mode entry and exit.
Auto Precharge
Two methods areavailableto precharge
SDRAMs. In an automatic precharge m ode, the
CAS timing accepts one extra address, A
, to de-
10
termine whether the chip restores or not after the
operation. If A
is high when a Rea d Command is
10
issued, the Read with Auto-Precharge function is
initiated. The SDRAM automatically enters the precharge operation one clock before th e last data out
for CAS
If A
latencies2, twoclocksfor CAS latencies 3.
is high when a Write Command is issued, t he
10
Write with Auto-Precharge func tion is initiated.
The SDRAM automatically enters the prechargeoperation a time delay equal to t
(Write recovery
WR
time) after the last data in.
Precharge Command
There is also a s eparate precharge command
available. When RAS
and WE are low and CAS is
high at a clock timing, it triggers the prec harge operation. With A
being low, the BA is used select
10
bank toprecharge. Theprecharge command can be
imposed one clock before the last da ta out for CAS
latency = 2, two clock s before the last data out for
CAS latency = 3. Writes require a time delay twr
from the last data out to apply the precharge c ommand. If A
is high , all banks will be precharged.
10
Burst Termination
Once a burst read or write operation has been initiated, there are several methods in which to terminate the burst operation prematurely. These
methods include using another Read or Write Command to interrupt an existing burst operation, use a
Precharge Command to interrupt a burst cycle and
close the act ive bank, or using the Burst Stop Command to terminate the existing burst operation but
leave the bank open for future Read or Write Commands to the same page of the active bank. When
interrupting a burst with another Read or Write
Command care must be taken to avoid I/O contention. The Burst Stop Command, however, has the
fewest restrictions making it the easiest method to
use when terminating a burstoperation before ithas
been completed. Ifa Burst Stop command is issued
during a burst write operation, then any residual
data from t he burst write cycle will be ignored . Data
that is presented on the I/O pins before the Burst
Stop Command is registered will be writte n to the
memory.
V54C316162V Rev. 2.9 September 2001
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