74hct670 NXP Semiconductors, 74hct670 Datasheet - Page 2

• Manufacturer Part Number: 74hct670
• Description: 4 X 4 Register File; 3-state
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FEATURES
GENERAL DESCRIPTION
The 74HC/HCT670 are high-speed Si-gate CMOS devices
and are pin compatible with low power Schottky TTL
(LSTTL). They are specified in compliance with JEDEC
standard no. 7A.
The 74HC/HCT670 are 16-bit 3-state register files
organized as 4 words of 4 bits each. Separated read and
write address inputs (R
inputs (RE and WE) 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 (D
QUICK REFERENCE DATA
GND = 0 V; T
Notes
1. C
2. For HC the condition is V
ORDERING INFORMATION
See
December 1990
SYMBOL PARAMETER
t
C
C
PHL
Simultaneous and independent read and write
operations
Expandable to almost any word size and bit length
Output capability: bus driver
I
4 x 4 register file; 3-state
I
PD
CC
f
f
C
V
for HCT the condition is V
i
o
“74HC/HCT/HCU/HCMOS Logic Package Information”
/ t
CC
PD
L
category: MSI
= output frequency in MHz
= input frequency in MHz
(C
PLH
= output load capacitance in pF
P
is used to determine the dynamic power dissipation (P
= supply voltage in V
L
D
= C
V
propagation delay D
input capacitance
power dissipation capacitance per package
amb
CC
0
PD
to D
2
= 25 C; t
V
3
f
o
). The W
CC
) = sum of outputs
A
2
, R
f
r
B
i
= t
and W
A
I
I
f
= GND to V
and W
= GND to V
= 6 ns
(C
n
to Q
L
A
, W
B
V
n
inputs determine
CC
B
) and enable
2
CC
CC
;
f
1.5 V
o
)
where:
2
.
CONDITIONS
C
notes 1 and 2
the location of the stored word. When the WE input is
LOW, the data is entered into the addressed location. The
addressed location remains transparent to the data while
the WE input is LOW. Data supplied at the inputs will be
read out in true (non-inverting) form from the 3-state
outputs (Q
WE is HIGH.
Direct acquisition of data stored in any of the four registers
is made possible by individual read address inputs
(R
outputs when the RE is LOW. Data outputs are in the high
impedance OFF-state when RE is HIGH. This permits
outputs to be tied together to increase the word capacity to
very large numbers.
Design of the read enable signals for the stacked devices
must ensure that there is no overlap in the LOW levels
which would 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.
L
D
= 15 pF; V
A
in W):
and R
B
0
). The addressed word appears at the four
to Q
CC
= 5 V
3
). D
n
and W
23
3.5
122
n
inputs are inhibited when
HC
74HC/HCT670
TYPICAL
Product specification
23
3.5
124
HCT
ns
pF
pF
UNIT