74HCT283 View Datasheet(PDF) - Philips Electronics
Part Name
Description
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74HCT283 Datasheet PDF : 8 Pages
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Philips Semiconductors
4-bit binary full adder with fast carry
Product specification
74HC/HCT283
FEATURES
• High-speed 4-bit binary addition
• Cascadable in 4-bit increments
• Fast internal look-ahead carry
• Output capability: standard
• ICC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT283 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/HCT283 add two 4-bit binary words (An plus Bn)
plus the incoming carry. The binary sum appears on the
sum outputs (∑1 to ∑4) and the out-going carry (COUT)
according to the equation:
CIN + (A1 + B1) + 2(A2 + B2) + +4(A3 + B3) + 8(A4 + B4) =
= ∑1 + 2∑2 + 4∑3 + 8∑4 + 16COUT
Where (+) = plus.
Due to the symmetry of the binary add function, the “283”
can be used with either all active HIGH operands (positive
logic) or all active LOW operands (negative logic); see
function table. In case of all active LOW operands the
results ∑1 to ∑4 and COUT should be interpreted also as
active LOW. With active HIGH inputs, CIN must be held
LOW when no “carry in” is intended. Interchanging inputs
of equal weight does not affect the operation, thus CIN, A1,
B1 can be assigned arbitrarily to pins 5, 6, 7, etc.
See the “583” for the BCD version.
QUICK REFERENCE DATA
GND = 0 V; Tamb = 25 °C; tr = tf = 6 ns
SYMBOL PARAMETER
CONDITIONS
tPHL/ tPLH
CI
CPD
propagation delay
CIN to ∑1
CIN to ∑2
CIN to ∑3
CIN to ∑4
An or Bn to ∑n
CIN to COUT
An or Bn to COUT
input capacitance
power dissipation capacitance per package
CL = 15 pF; VCC = 5 V
notes 1 and 2
Notes
1. CPD is used to determine the dynamic power dissipation (PD in µW):
PD = CPD × VCC2 × fi + ∑ (CL × VCC2 × fo) where:
fi = input frequency in MHz
fo = output frequency in MHz
∑ (CL × VCC2 × fo) = sum of outputs
CL = output load capacitance in pF
VCC = supply voltage in V
2. For HC the condition is VI = GND to VCC
For HCT the condition is VI = GND to VCC − 1.5 V
TYPICAL
HC
HCT
UNIT
16
15
ns
18
21
ns
20
23
ns
23
27
ns
21
25
ns
20
23
ns
20
24
ns
3.5
3.5
pF
88
92
pF
December 1990
2
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