Philips Semiconductors Product specification
74F244/74F244BOctal buffers (3-State)
2
1994 Dec 5 853-0357 14381
FEATURES
• Octal bus interface
• 3-State output buffer sink 64mA
• 15mA source current
• Guaranteed output skew less than 2.0ns (74F244B)
• Reduced ground bounce (74F244B)
• Reduced I
CC
(74F244B)
• Reduced loading (74F244B I
IL
= 40µA)
• Split lead frame offers increased noise immunity (74F244B)
• Industrial temperature range available (-40°C to +85°C) for
74F244
• 74F244 available in SSOP Type II package
DESCRIPTION
The 74F244 is an octal buffer that is ideal for driving bus lines of
buffer memory address registers. The outputs are all capable of
sinking 64mA and sourcing up to 15mA, producing very good
capacitive drive characteristics. The device features two output
enables, OE
a and OEb, each controlling four of the 3-State outputs.
The 74F244B is functionally equivalent to the 74F244. It has been
designed to reduce effects of ground noise. Other advantages are
noted in the features.
TYPE
TYPICAL
PROPAGATION
DELAY
TYPICAL SUPPLY
CURRENT (TOTAL)
74F244 4.0ns 53mA
74F244B 4.0ns 33mA
ORDERING INFORMATION
ORDER CODE
COMMERCIAL RANGE INDUSTRIAL RANGE
DESCRIPTION
V
CC
= 5V ±10%, V
CC
= 5V ±10%,
T
amb
= 0°C to +70°C T
amb
= -40°C to +85°C
20-pin plastic DIP N74F244N, N74F244BN I74F244N SOT146-1
20-pin plastic SOL N74F244D, N74F244BD I74F244D SOT163-1
20-pin plastic SSOP II N74F244DB SOT339-1
INPUT AND OUTPUT LOADING AND FAN OUT TABLE
PINS DESCRIPTION
74F (U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
Ian, Ibn Data inputs (74F244) 1.0/2.67 20µA/1.6mA
Data inputs (74F244B) 1.0/0.067 20µA/40µA
OEa, OEb Output enable inputs (active low) (74F244) 1.0/1.67 20µA/1.0mA
Output enable inputs (active low) (74F244B) 1.0/0.067 20µA/40µA
Yan, Ybn Data outputs 750/106.7 15mA/64mA
NOTE: One (1.0) FAST unit load is defined as: 20µA in the high state and 0.6mA in the low state.
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10 11
12
13
14
15
16
17
18
19
20
V
CC
OEa
Ia0
Yb0
Ia1
Yb1
Ia2
Yb2
Ia3
Yb3
GND
SF00227
OEb
Ya0
Ib0
Ya1
Ib1
Ya2
Ib2
Ya3
Ib3
LOGIC SYMBOL
OEa
1
SF00228
2 4 6 8 17 15 13 11
18 16 14 12 3 5 7 9
Ia0 Ia1 Ia2 Ia3 Ib0 Ib1 Ib2 Ib3
Ya0 Ya1 Ya2 Ya3 Yb0 Yb1 Yb2 Yb3
V
CC
= Pin 20
GND = Pin 10
OEb19
