Philips 74f670 DATASHEETS
INTEGRATED CIRCUITS
74F670
4 x 4 register file (3-State)
Product specification
IC15 Data Handbook
1990 Jul 12
Philips Semiconductors Product specification
74F6704 x 4 register file (3-State)
FEA TURES
•Simultaneous and Independent Read and Write operations
•Expandable to almost any word size and bit length
•3-State outputs
DESCRIPTION
The 74F670 is a 16-bit 3-State Register File organized as 4 words of
4 bits each. Separate Read and Write Address and Enable inputs
are available, permitting simultaneous writing into one word location
and reading from another location. The 4-bit word to be stored is
presented to four data inputs.
The Write address inputs (WA and WB) determine the location of the
stored word. The Write Address inputs should only be changed
when the Write Enable input (WE
operation. When the WE
is Low, the data is entered into the
addressed location.
The addressed location remains transparent to the data while the
WE
is Low. Data supplied at the inputs will be read out in true
(non-inverting) form from the 3-State outputs. Data and address
inputs are inhibited when the WE is High. Direct acquisition of data
stored in any of the four registers is made possible by individual
Read Address inputs (RA, RB). The addressed word appears at the
four outputs when the Read Enable (RE
the high impedance “off” state when the RE
outputs to be tied together to increase the word capacity to very
large numbers.
Up to 128 devices can be stacked to increase the word size to 512
locations by tying the 3-State outputs together. Since the limiting
factor for expansion is the output High current, further stacking is
possible by tying pullup reisistors to the outputs to increase the I
current available. Design of the Read Enable signals for the stacked
devices must ensure that there is no overlap in the Low levels which
cause more than one output to be active at the same time. Parallel
expansion to generate n-bit words is accomplished by driving the
Enable and address inputs of each device in parallel.
) is High for conventional
) is Low. Data outputs are in
is High. This permits
OH
PIN CONFIGURATION
1
D1
2
D2
3
D3
4
RB
5
RA
Q3
6
7
Q2
GND
8
TYPICAL
TYPE
PROPAGATION
DELAY
74F670 6.5ns 50mA
V
16
CC
15
D0
14
WA
13
WB
12
WE
11
RE
10
Q0
Q1
9
SF01178
TYPICAL
SUPPLY CURRENT
(TOTAL)
ORDERING INFORMATION
COMMERCIAL RANGE
DESCRIPTION
16-pin plastic DIP N74F670N SOT38-4
16-pin plastic SOL N74F670D SOT162-1
VCC = 5V ±10%,
T
= 0°C to +70°C
amb
PKG DWG #
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS DESCRIPTION
74F(U.L.)
HIGH/LOW
D0 - D3 Data inputs 1.0/1.0 20µA/0.6mA
WA, WB Write address inputs 1.0/1.0 20µA/0.6mA
RA, RB Read address inputs 1.0/1.0 20µA/0.6mA
WE Write Enable inputs 1.0/1.0 20mA/0.6mA
RE Read Enable inputs 1.0/1.0 20mA/0.6mA
Q0–Q3 Data output 150/40 3.0mA/24mA
NOTE:
One (1.0) FAST Unit Load is defined as: 20µA in the High state and 0.6mA in the Low state.
1990 Jul 12 853-0014 99965
2
LOAD VALUE
HIGH/LOW
Philips Semiconductors Product specification
OPERATING MODE
Read
OPERATING MODE
Write data
74F6704 x 4 register file (3-State)
LOGIC SYMBOL
14 13 5 4 15 1 2 3
WA WB RA RB D0 D1 D2 D3
WE
12
RE
11
Q3Q2
76
SF01179
V
=Pin 16
CC
GND=Pin 8
Q1Q0
10 9
WORD SELECT FUNCTION TABLE
WRITE MODE READ MODE OPERATING MODE
WB WA RB RA Word Selected
L L L L W ord 0
L H L H Word 1
H L H L Word 2
H H H H Word 3
H = High voltage level
L = Low voltage level
READ MODE FUNCTION TABLE
INPUT
RE
INTERNAL
LATCHES*
L L L
L H H
H X Z Disabled
H = High voltage level
L = Low voltage level
X = Don’t care
Z = High impedance “off” state
* = The selection of “internal latches” by Read Address
(RA and RB) are not constrained by WE
OUTPUT
Qn
or RE operation.
LOGIC SYMBOL (IEEE/IEC)
14
13
5
4
12
11
15
1
2
3
RAM 4X4
0
0
1A
3
1
0
0
2A
3
1
C4 [WRITE]
EN [READ]
1A, 4D
10
2A
9
7
6
SF01180
WRITE MODE FUNCTION TABLE
INPUTS
WE Dn
L L L
L H H
H X NC Data latched
H = High voltage level
L = Low voltage level
NC= No change
X = Don’t care
* = The write address (WA and WB) to the “internal latches”
must be stabled while WE
INTERNAL
LATCHES*
is Low for conventional operation.
1990 Jul 12
3
Philips Semiconductors Product specification
74F6704 x 4 register file (3-State)
LOGIC DIAGRAM
11
RE
5
RA
4
RB
12
WE
13
WB
14
WA
6
Q
E
D
3
D3
Q
E
D
Q
E
D
Q
E
D
Q3
2
D2
1
D1
15
D0
V
=Pin 16
CC
GND=Pin 8
7
9
10
SF01181
Q2
Q1
Q0
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
Q
E
D
1990 Jul 12
4
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