128K x 36
3.3V Synchronous ZBT™ SRAMs
2.5V I/O, Burst Counter
Pipelined Outputs
◆
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IDT71V2556S/XS
IDT71V2556SA/XSA
Features
128K x 36 memory configurations
Supports high performance system speed - 166 MHz
(3.5 ns Clock-to-Data Access)
ZBT
TM
Feature - No dead cycles between write and read
cycles
Internally synchronized output buffer enable eliminates the
need to control
OE
Single R/W (READ/WRITE) control pin
Positive clock-edge triggered address, data, and control
signal registers for fully pipelined applications
4-word burst capability (interleaved or linear)
Individual byte write (BW
1
-
BW
4
) control (May tie active)
Three chip enables for simple depth expansion
3.3V power supply (±5%), 2.5V I/O Supply (V
DDQ)
Optional - Boundary Scan JTAG Interface (IEEE 1149.1
complaint)
Packaged in a JEDEC standard 100-pin plastic thin quad
flatpack (TQFP) and 119 ball grid array (BGA)
The IDT71V2556 is a 3.3V high-speed 4,718,592-bit (4.5 Megabit)
synchronous SRAM. It is designed to eliminate dead bus cycles when
turning the bus around between reads and writes, or writes and reads.
Thus, they have been given the name ZBT
TM
, or Zero Bus Turnaround.
Description
Address and control signals are applied to the SRAM during one clock
cycle, and two cycles later the associated data cycle occurs, be it read
or write.
The IDT71V2556 contains data I/O, address and control signal
registers. Output enable is the only asynchronous signal and can be used
to disable the outputs at any given time.
A Clock Enable (CEN) pin allows operation of the IDT71V2556 to be
suspended as long as necessary. All synchronous inputs are ignored
when (CEN) is high and the internal device registers will hold their previous
values.
There are three chip enable pins (CE
1
, CE
2
,
CE
2
) that allow the user
to deselect the device when desired. If any one of these three are not
asserted when ADV/LD is low, no new memory operation can be initiated.
However, any pending data transfers (reads or writes) will be completed.
The data bus will tri-state two cycles after chip is deselected or a write is
initiated.
The IDT71V2556 has an on-chip burst counter. In the burst mode, the
IDT71V2556 can provide four cycles of data for a single address
presented to the SRAM. The order of the burst sequence is defined by the
LBO
input pin. The
LBO
pin selects between linear and interleaved burst
sequence. The ADV/LD signal is used to load a new external address
(ADV/LD = LOW) or increment the internal burst counter (ADV/LD =
HIGH).
The IDT71V2556 SRAMs utilize IDT's latest high-performance CMOS
process and are packaged in a JEDEC standard 14mm x 20mm 100-pin
thin plastic quad flatpack (TQFP) as well as a 119 ball grid array (BGA).
Pin Description Summary
A
0
-A
16
CE
1
, CE
2
,
CE
2
OE
R/
W
CEN
BW
1
,
BW
2
,
BW
3
,
BW
4
CLK
ADV/
LD
LBO
TMS
TDI
TCK
TDO
TRST
ZZ
I/O
0
-I/O
31
, I/O
P1
-I/O
P4
V
DD
, V
DDQ
V
SS
Ad d re ss Inp uts
Chip Enab le s
Outp ut Enab le
Re ad /Write Sig nal
Clo ck Enab le
Ind ivid ual Byte Write Se le cts
Clo ck
Ad vance b urst ad d re ss / Lo ad ne w ad d re ss
Line ar / Inte rle ave d Burst Ord e r
Te st Mo d e Se le ct
Te st Data Inp ut
Te st Clo ck
Te st Data Outp ut
JTAG Re se t (Op tio nal)
S le e p Mo d e
Data Inp ut / Outp ut
Co re Po we r, I/O Po we r
Gro und
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Inp ut
Outp ut
Inp ut
Inp ut
I/O
Sup p ly
Sup p ly
Synchro no us
Synchro no us
Asynchro no us
Synchro no us
Synchro no us
Synchro no us
N/A
Synchro no us
Static
Synchro no us
Synchro no us
N/A
Synchro no us
Asynchro no us
Synchro no us
Synchro no us
Static
Static
4875 tb l 01
1
©2011
Integrated Device Technology, Inc.
APRIL 2011
DSC-4875/12
IDT71V2556, 128K x 36, 3.3V Synchronous ZBT™ SRAMs
with 2.5V I/O, Burst Counter, and Pipelined Outputs
Commercial and Industrial Temperature Ranges
Pin Definitions
(1)
Symbol
A
0
-A
16
ADV/
LD
Pin Function
Ad d re ss Inp uts
Ad vance / Lo ad
I/O
I
I
Active
N/A
N/A
Description
Synchro no us Ad d re ss inp uts. The ad d re ss re g iste r is trig g e re d b y a co mb inatio n o f the rising e d g e o f
CLK, ADV/
LD
lo w,
CEN
lo w, and true chip e nab le s.
ADV/
LD
is a synchro no us inp ut that is use d to lo ad the inte rnal re g iste rs with ne w ad d re ss and co ntro l
whe n it is samp le d lo w at the rising e d g e o f clo ck with the chip se le cte d . Whe n ADV/
LD
is lo w with
the chip d e se le cte d , any b urst in p ro g re ss is te rminate d . Whe n ADV/
LD
is samp le d hig h the n the
inte rnal b urst co unte r is ad vance d fo r any b urst that was in p ro g re ss. The e xte rnal ad d re sse s are
ig no re d whe n ADV/
LD
is samp le d hig h.
R/
W
sig nal is a synchro no us inp ut that id e ntifie s whe the r the curre nt lo ad cycle initiate d is a Re ad o r
Write acce ss to the me mo ry array. The d ata b us activity fo r the curre nt cycle take s p lace two clo ck
cycle s late r.
Synchro no us Clo ck Enab le Inp ut. Whe n
CEN
is samp le d hig h, all o the r synchro no us inp uts, includ ing
clo ck are ig no re d and o utp uts re main unchang e d . The e ffe ct o f
CEN
samp le d hig h o n the d e vice
o utp uts is as if the lo w to hig h clo ck transitio n d id no t o ccur. Fo r no rmal o p e ratio n,
CEN
must b e
samp le d lo w at rising e d g e o f clo ck.
Synchro no us b yte write e nab le s. Each 9-b it b yte has its o wn active lo w b yte write e nab le . On lo ad
write cycle s (Whe n R/
W
and ADV/
LD
are samp le d lo w) the ap p ro p riate b yte write sig nal (
BW
1
-
BW
4
)
must b e valid . The b yte write sig nal must also b e valid o n e ach cycle o f a b urst write . Byte Write
sig nals are ig no re d whe n R/
W
is samp le d hig h. The ap p ro p riate b yte (s) o f d ata are writte n into the
d e vice two cycle s late r.
BW
1
-
BW
4
can all b e tie d lo w if always d o ing write to the e ntire 36-b it wo rd .
Synchro no us active lo w chip e nab le .
CE
1
and
CE
2
are use d with CE
2
to e nab le the IDT71V2556.
(
CE
1
o r
CE
2
samp le d hig h o r CE
2
samp le d lo w) and ADV/
LD
lo w at the rising e d g e o f clo ck, initiate s a
d e se le ct cycle . The ZBT
TM
has a two cycle d e se le ct, i.e ., the d ata b us will tri-state two clo ck cycle s
afte r d e se le ct is initiate d .
Synchro no us active hig h chip e nab le . CE
2
is use d with
CE
1
and
CE
2
to e nab le the chip . CE
2
has
inve rte d p o larity b ut o the rwise id e ntical to
CE
1
and
CE
2
.
This is the clo ck inp ut to the IDT71V2556. Exce p t fo r
OE
, all timing re fe re nce s fo r the d e vice are mad e
with re sp e ct to the rising e d g e o f CLK.
Synchro no us d ata inp ut/o utp ut (I/O) p ins. Bo th the d ata inp ut p ath and d ata o utp ut p ath are re g iste re d
and trig g e re d b y the rising e d g e o f CLK.
Burst o rd e r se le ctio n inp ut. Whe n
LBO
is hig h the Inte rle ave d b urst se q ue nce is se le cte d . Whe n
LBO
is lo w the Line ar b urst se q ue nce is se le cte d .
LBO
is a static inp ut and it must no t chang e d uring
d e vice o p e ratio n.
Asynchro no us o utp ut e nab le .
OE
must b e lo w to re ad d ata fro m the 71V2556. Whe n
OE
is hig h the I/O
p ins are in a hig h-imp e d ance state .
OE
d o e s no t ne e d to b e active ly co ntro lle d fo r re ad and write
cycle s. In no rmal o p e ratio n,
OE
can b e tie d lo w.
Give s inp ut co mmand fo r TAP co ntro lle r. Samp le d o n rising e d g e o f TDK. This p in has an inte rnal
p ullup .
Se rial inp ut o f re g iste rs p lace d b e twe e n TDI and TDO. Samp le d o n rising e d g e o f TCK. This p in has
an inte rnal p ullup .
Clo ck inp ut o f TAP co ntro lle r. Each TAP e ve nt is clo cke d . Te st inp uts are cap ture d o n rising e d g e o f
TCK, while te st o utp uts are d rive n fro m the falling e d g e o f TCK. This p in has an inte rnal p ullup .
Se rial o utp ut o f re g iste rs p lace d b e twe e n TDI and TDO. This o utp ut is active d e p e nd ing o n the state o f
the TAP co ntro lle r.
Op tio nal Asynchro no us JTAG re se t. Can b e use d to re se t the TAP co ntro lle r, b ut no t re q uire d . JTAG
re se t o ccurs auto matically at p o we r up and also re se ts using TMS and TCK p e r IEEE 1149.1. If no t
use d
TRST
can b e le ft flo ating . This p in has an inte rnal p ullup .
Synchro no us sle e p mo d e inp ut. ZZ HIGH will g ate the CLK inte rnally and p o we r d o wn the IDT71V2556
to its lo we st p o we r co nsump tio n le ve l. Data re te ntio n is g uarante e d in Sle e p Mo d e . This p in has an
inte rnal p ulld o wn
3.3V co re p o we r sup p ly.
2.5V I/O Sup p ly.
Gro und .
4875 tb l 02
R/
W
Re ad / Write
I
N/A
CEN
Clo ck Enab le
I
LOW
BW
1
-
BW
4
Ind ivid ual Byte
Write Enab le s
I
LOW
CE
1
,
CE
2
Chip Enab le s
I
LOW
CE
2
CLK
I/O
0
-I/O
31
I/O
P1
-I/O
P4
LBO
Chip Enab le
Clo ck
Data Inp ut/Outp ut
Line ar Burst Ord e r
I
I
I/O
I
HIGH
N/A
N/A
LOW
OE
Outp ut Enab le
I
LOW
TMS
TDI
TCK
TDO
Te st Mo d e Se le ct
Te st Data Inp ut
Te st Clo ck
Te st Data Outp ut
JTAG Re se t
(Op tio nal)
I
I
I
O
N/A
N/A
N/A
N/A
TRST
I
LOW
ZZ
V
DD
V
DDQ
V
SS
S le e p Mo d e
Po we r Sup p ly
Po we r Sup p ly
Gro und
I
N/A
N/A
N/A
HIGH
N/A
N/A
N/A
NOTE:
1. All synchronous inputs must meet specified setup and hold times with respect to CLK.
6.42
2
IDT71V2556, 128K x 36, 3.3V Synchronous ZBT™ SRAMs
with 2.5V I/O, Burst Counter, and Pipelined Outputs
Commercial and Industrial Temperature Ranges
Functional Block Diagram
LBO
Address A [0:16]
CE1,
CE2,
CE2
R/W
CEN
ADV/LD
BWx
D
Clk
D
Q
Control
D
Q
128Kx36 BIT
MEMORY ARRAY
Address
Input Register
DI
DO
Q
Control Logic
Mux
Sel
D
Clk
Clock
Output Register
Q
OE
Gate
4875 drw 01a
,
(optional)
TMS
TDI
TCK
TRST
JTAG
(SA Version)
TDO
Data I/O [0:31],
I/O P[1:4]
Recommended DC Operating
Conditions
Symbol
V
DD
V
DDQ
V
SS
V
IH
V
IH
V
IL
Parameter
Co re Sup p ly Vo ltag e
I/O Sup p ly Vo ltag e
Sup p ly Vo ltag e
Inp ut Hig h Vo ltag e - Inp uts
Inp ut Hig h Vo ltag e - I/O
Inp ut Lo w Vo ltag e
Min.
3.135
2.375
0
1.7
1.7
-0.3
(1)
Typ.
3.3
2.5
0
____
____
____
Max.
3.465
2.625
0
V
DD
+0.3
V
DDQ
+0.3
(2)
0.7
Unit
V
V
V
V
V
V
4875 tb l 03
NOTES:
1. V
IL
(min.) = –1.0V for pulse width less than t
CYC
/2, once per cycle.
2. V
IH
(max.) = +6.0V for pulse width less than t
CYC
/2, once per cycle.
6.42
3
IDT71V2556, 128K x 36, 3.3V Synchronous ZBT™ SRAMs
with 2.5V I/O, Burst Counter, and Pipelined Outputs
Commercial and Industrial Temperature Ranges
Recommended Operating
Temperature and Supply Voltage
Grade
Co mme rcial
Ind ustrial
Temperature
(1)
0° C to +70° C
-40° C to +85° C
V
SS
0V
0V
V
DD
3.3V± 5%
3.3V± 5%
V
DDQ
2.5V± 5%
2.5V± 5%
4875 tb l 05
NOTE:
1. T
A
is the "instant on" case temperature.
100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81
I/O
P3
I/O
16
I/O
17
V
DDQ
V
SS
I/O
18
I/O
19
I/O
20
I/O
21
V
SS
V
DDQ
I/O
22
I/O
23
V
DD
(1)
V
DD
V
DD
(1)
V
SS
I/O
24
I/O
25
V
DDQ
V
SS
I/O
26
I/O
27
I/O
28
I/O
29
V
SS
V
DDQ
I/O
30
I/O
31
I/O
P4
CE
2
BW
4
BW
3
BW
2
BW
1
CE
2
V
DD
V
SS
CLK
R/W
CEN
OE
ADV/LD
NC
(2)
NC
(2)
A
8
A
9
Pin Configuration — 128K x 36
A
6
A
7
CE
1
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
26
27
28
29
30
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
I/O
P2
I/O
15
I/O
14
V
DDQ
V
SS
I/O
13
I/O
12
I/O
11
I/O
10
V
SS
V
DDQ
I/O
9
I/O
8
V
SS
V
DD
(1)
V
DD
V
SS/ZZ
(3)
I/O
7
I/O
6
V
DDQ
V
SS
I/O
5
I/O
4
I/O
3
I/O
2
V
SS
V
DDQ
I/O
1
I/O
0
I/O
P1
4875 drw 02
,
LBO
A
5
A
4
A
3
A
2
A
1
A
0
NC
NC
V
SS
V
DD
NC
NC
Top View
TQFP
NOTES:
1. Pins 14, 16 and 66 do not have to be connected directly to V
DD
as long as the input voltage is
≥
V
IH
.
2. Pins 83 and 84 are reserved for future 8M and 16M respectively.
3. Pin 64 does not have to be connected directly to V
SS
as long as the input voltage is
≤
V
IL
; on the latest die revision this pin supports ZZ (sleep mode).
6.42
4
A
10
A
11
A
12
A
13
A
14
A
15
A
16
IDT71V2556, 128K x 36, 3.3V Synchronous ZBT™ SRAMs
with 2.5V I/O, Burst Counter, and Pipelined Outputs
Commercial and Industrial Temperature Ranges
Absolute Maximum Ratings
(1)
Symbol
V
TERM
(2)
100 TQFP Capacitance
(1)
Unit
V
V
V
V
Rating
Te rminal Vo ltag e with
Re sp e ct to GND
Te rminal Vo ltag e with
Re sp e ct to GND
Te rminal Vo ltag e with
Re sp e ct to GND
Te rminal Vo ltag e with
Re sp e ct to GND
Commerical
Op e rating Te mp e rature
Commercial &
Industrial Values
-0.5 to +4.6
-0.5 to V
DD
-0.5 to V
DD
+0.5
-0.5 to V
DDQ
+0.5
(T
A
= +25° C, f = 1.0MHz)
Symbol
C
IN
C
I/O
Parameter
(1)
Inp ut Cap acitance
I/O Cap acitance
Conditions
V
IN
= 3d V
V
OUT
= 3d V
Max.
5
7
Unit
pF
pF
4875 tb l 07
V
TERM
(3,6)
V
TERM
(4,6)
V
TERM
(5,6)
NOTE:
1. This parameter is guaranteed by device characterization, but not production
tested.
119 BGA Capacitance
(1)
(T
A
= +25° C, f = 1.0MHz)
Symbol
Parameter
(1)
Inp ut Cap acitance
I/O Cap acitance
Conditions
V
IN
= 3d V
V
OUT
= 3d V
Max.
7
7
Unit
pF
pF
4875 tb l 07a
-0 to +70
-40 to +85
-55 to +125
-55 to +125
2.0
50
o
C
C
C
C
T
A
(7)
Industrial
Op e rating Te mp e rature
T
BIAS
T
STG
P
T
I
OUT
Te mp e rature
Und e r Bias
Sto rag e
Te mp e rature
Po we r Dissip atio n
DC Outp ut Curre nt
o
C
IN
C
I/O
o
o
NOTE:
1. This parameter is guaranteed by device characterization, but not production
tested.
W
mA
4875 tb l 06
NOTES:
1. Stresses 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. V
DD
terminals only.
3. V
DDQ
terminals only.
4. Input terminals only.
5. I/O terminals only.
6. This is a steady-state DC parameter that applies after the power supply has
reached its nominal operating value. Power sequencing is not necessary;
however, the voltage on any input or I/O pin cannot exceed V
DDQ
during power
supply ramp up.
7. T
A
is the "instant on" case temperature.
6.42
5
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