Philips Semiconductors
Buffers/drivers
Product specification
74F655A*
74F656A
74F655A Octal buffer/driver with parity, inverting (3-State)
74F656A Octal buffer/driver with parity, non-inverting (3-State)
FEATURES
• Significantly improved AC performance over 74F655 and 74F656
• High impedance NPN base input for reduced loading
(40µA in High and Low states)
• Ideal in applications where high output drive and light bus loading
are required (IIL is 40µA vs. FAST std of 600µA)
• 74F655A combines 74F240 and 74F280A functions in one
package
• 74F656A combines 74F244 and 74F280A functions in one
package
• 74F655A Inverting
• 74F656A Non-inverting
• 3-State outputs sink 64mA and source 15mA
• 24-pin plastic Slim DIP (300mil) package
• Inputs on one side and outputs on the other side simplifies PC
board layout
• Combined functions reduce part count and enhance system
performance
• Industrial temperature range available (–40°C to +85°C)
DESCRIPTION
The 74F655A and 74F656A are octal buffers and line drivers with
parity generation/checking designed to be employed as memory
address drivers, clock drivers and bus-oriented
transmitters/receivers. These parts include parity generator/checker
to improve PC board density.
TYPE
74F655A
74F656A
TYPICAL
PROPAGATION
DELAY
6.5ns
6.5ns
TYPICAL SUPPLY CURRENT
(TOTAL)
64mA
64mA
ORDERING INFORMATION
DESCRIPTION
COMMERCIAL RANGE
VCC = 5V ±10%,
Tamb = 0°C to +70°C
24-pin Plastic Slim
DIP (300mil)
N74F656AN
24-pin Plastic SOL
N74F656AD
INDUSTRIAL RANGE
VCC = 5V ±10%,
Tamb = –40°C to +85°C
I74F656AN
I74F656AD
PKG DWG #
SOT222-1
SOT137-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74F(U.L.)
HIGH/LOW
D0–D7
Data inputs
2.0/0.066
PI
Parity input
1.0/0.033
OE0, OE1, OE2
Output Enable Inputs (active Low)
1.0/0.033
ΣE, ΣO
Parity outputs
750/106.7
Q0–Q7
Data outputs (74F655A)
750/106.7
Q0–Q7
Data outputs (74F656A)
750/106.7
NOTE: One (1.0) FAST Unit Load (U.L.) is defined as: 20µA in the High state and 0.6mA in the Low state.
LOAD VALUE
HIGH/LOW
40µA/40µA
20µA/20µA
20µA/20µA
15mA/64mA
15mA/64mA
15mA/64mA
* Discontinued part. Please see the Discontinued Products List.
1991 Jul 17
2
853-0383 03305