Philips Semiconductors
Product specification
4 x 4 register file (3-State)
74F670
FEATURES
•
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) is High for conventional
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) is Low. Data outputs are in
the high impedance “off” state when the RE is High. This permits
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
OH
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.
PIN CONFIGURATION
D1
D2
D3
RB
RA
Q3
Q2
GND
1
2
3
4
5
6
7
8
16 V
CC
15 D0
14 WA
13 WB
12 WE
11 RE
10 Q0
9
Q1
SF01178
TYPE
74F670
TYPICAL
PROPAGATION
DELAY
6.5ns
TYPICAL
SUPPLY CURRENT
(TOTAL)
50mA
ORDERING INFORMATION
DESCRIPTION
16-pin plastic DIP
16-pin plastic SOL
COMMERCIAL RANGE
V
CC
= 5V
±10%,
T
amb
= 0°C to +70°C
N74F670N
N74F670D
PKG DWG #
SOT38-4
SOT162-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
D0 - D3
WA, WB
RA, RB
WE
RE
Q0–Q3
DESCRIPTION
Data inputs
Write address inputs
Read address inputs
Write Enable inputs
Read Enable inputs
Data output
74F(U.L.)
HIGH/LOW
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
150/40
LOAD VALUE
HIGH/LOW
20µA/0.6mA
20µA/0.6mA
20µA/0.6mA
20mA/0.6mA
20mA/0.6mA
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
2
853-0014 99965
Philips Semiconductors
Product specification
4 x 4 register file (3-State)
74F670
LOGIC SYMBOL
14 13
5
4
15
1
2
3
LOGIC SYMBOL (IEEE/IEC)
14
0
13
WA WB RA RB D0 D1 D2 D3
5
0
4
12
Q0
Q1
Q2
Q3
11
2A
1
0
3
1A
1
RAM 4X4
0
3
12
11
WE
RE
C4 [WRITE]
EN [READ]
10
2A
9
7
6
10
V
CC
=Pin 16
GND=Pin 8
9
7
6
15
1
2
3
1A, 4D
SF01179
SF01180
WORD SELECT FUNCTION TABLE
WRITE MODE
WB
L
L
H
WA
L
H
L
READ MODE
RB
L
L
H
RA
L
H
L
H
OPERATING MODE
Word Selected
Word 0
Word 1
Word 2
Word 3
WRITE MODE FUNCTION TABLE
INPUTS
WE
L
L
Dn
L
H
INTERNAL
LATCHES*
L
H
OPERATING MODE
Write data
H
H
H
H = High voltage level
L = Low voltage level
READ MODE FUNCTION TABLE
INPUT
RE
L
L
H
L
X
Z
*
INTERNAL
LATCHES*
L
H
OUTPUT
OPERATING MODE
Qn
L
H
Read
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 is Low for conventional operation.
H
X
Z
Disabled
= High voltage level
= Low voltage level
= Don’t care
= High impedance “off” state
= The selection of “internal latches” by Read Address
(RA and RB) are not constrained by WE or RE operation.
1990 Jul 12
3
Philips Semiconductors
Product specification
4 x 4 register file (3-State)
74F670
ABSOLUTE MAXIMUM RATINGS
(Operation beyond the limits set forth in this table may impair the useful life of the device.
Unless otherwise noted these limits are over the operating free-air temperature range.)
SYMBOL
V
CC
V
IN
I
IN
V
OUT
I
OUT
T
amb
T
stg
Supply voltage
Input voltage
Input current
Voltage applied to output in High output state
Current applied to output in Low output state
Operating free-air temperature range
Storage temperature
PARAMETER
RATING
–0.5 to +7.0
–0.5 to +7.0
–30 to +5
–0.5 to V
CC
48
0 to +70
–65 to +150
UNIT
V
V
mA
V
mA
°C
°C
RECOMMENDED OPERATING CONDITIONS
SYMBOL
V
CC
V
IH
V
IL
I
IK
I
OH
I
OL
T
amb
Supply voltage
High-level input voltage
Low-level input voltage
Input clamp current
High-level output current
Low-level output current
Operating free-air temperature range
0
PARAMETER
LIMITS
MIN
4.5
2.0
0.8
–18
–3
24
70
NOM
5.0
MAX
5.5
UNIT
V
V
V
mA
mA
mA
°C
DC ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range unless otherwise noted.)
LIMITS
SYMBOL
PARAMETER
TEST CONDITIONS
NO TAG
V
CC
= MIN, V
IL
= MAX
V
IH
= MIN, I
OH
= MAX
V
CC
= MIN, V
IL
= MAX
V
IH
= MIN, I
OL
= MAX
V
CC
= MIN, I
I
= I
IK
V
CC
= MAX, V
I
= 7.0V
V
CC
= MAX, V
I
= 2.7V
V
CC
= MAX, V
I
= 0.5V
V
CC
= MAX, V
O
= 2.7V
V
CC
= MAX, V
O
= 0.5V
V
CC
= MAX
I
CCH
I
CC
Supply current (total)
I
CCL
I
CCZ
V
CC
= MAX
–60
50
50
55
±10%V
CC
±5%V
CC
±10%V
CC
±5%V
CC
MIN
2.4
2.7
3.4
0.35
0.35
–0.73
0.50
0.50
–1.2
100
20
–0.6
50
–50
–150
70
70
80
V
V
µA
µA
mA
µA
µA
mA
mA
mA
mA
V
TYP
NO TAG
MAX
UNIT
V
O
OH
High-level
High level output voltage
V
O
OL
V
IK
I
I
I
IH
I
IL
I
OZH
I
OZL
I
OS
Low level output voltage
Low-level
Input clamp voltage
Input current at maximum input voltage
High-level input current
Low-level input current
Off state output current,
High-level voltage applied
Off state output current,
Low-level voltage applied
Short-circuit output current
NO TAG
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable type.
2. All typical values are at V
CC
= 5V, T
amb
= 25°C.
3. Not more than one output should be shorted at a time. For testing I
OS
, the use of high-speed test apparatus and/or sample-and-hold
techniques are preferable in order to minimize internal heating and more accurately reflect operational values. Otherwise, prolonged shorting
1990 Jul 12
5
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