74LVC244A Просмотр технического описания (PDF) - Philips Electronics
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74LVC244A
Philips Electronics
74LVC244A Datasheet PDF : 10 Pages
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Philips Semiconductors
Octal buffer/line driver with 5-volt
tolerant inputs/outputs (3-State)
Product specification
74LVC244A
74LVCH244A
AC CHARACTERISTICS
GND = 0V; tr = tf v 2.5ns; CL = 50pF; RL = 500Ω; Tamb = –40°C to +85°C.
SYMBOL
PARAMETER
WAVEFORM
VCC = 3.3V ±0.3V
MIN TYP1 MAX
tPHL
tPLH
tPZH
tPZL
Propagation delay
1An to 1Yn;
2An to 2Yn
3-State output enable time
1OE to 1Yn;
2OE to 2Yn
1, 3
1.5
3.5
5.9
2, 3
1.5
4.3
7.6
tPHZ
tPLZ
3-State output disable time
1OE to 1Yn;
2OE to 2Yn
2, 3
1.5
3.7
5.8
NOTE:
1. Unless otherwise stated, all typical values are at VCC = 3.3V and Tamb = 25°C.
LIMITS
VCC = 2.7V
MIN MAX
1.5
6.9
1.5
8.6
1.5
6.8
VCC = 1.2V
TYP
16.0
19.0
17.0
UNIT
ns
ns
ns
AC WAVEFORMS
VM = 1.5 V at VCC w 2.7 V; VM = 0.5 VCC at VCC < 2.7 V
VOL and VOH are the typical output voltage drop that occur with the
output load.
VX = VOL + 0.3V at VCC ≥ 2.7V; VX = VOL + 0.1 VCC at VCC < 2.7V
VY = VOH – 0.3V at VCC ≥ 2.7V; VY = VOH – 0.1 VCC at VCC < 2.7V
VI
INPUT
VM
GND
VOH
tPHL
tPLH
OUTPUT
VM
VOL
SY00041
Waveform 1. Input (Dn) to output (Qn) propagation delays.
VI
nOE INPUT
VM
GND
VCC
Qn OUTPUT
LOW-to-OFF
OFF-to-LOW
VOL
tPLZ
VX
tPZL
VM
TEST CIRCUIT
VCC
PULSE
GENERATOR
VIN
RT
D.U.T.
VOUT
CL
S1
2<VCC
Open
GND
RL=500 Ω
RL=500 Ω
Test Circuit for 3-State Outputs
SWITCH POSITION
TEST
tPLH/tPHL
tPLZ/tPZL
tPHZ/tPZH
SWITCH
Open
2<VCC
GND
VCC
t 2.7V
2.7 – 3.6V
VIN
VCC
2.7V
DEFINITIONS
RL = Load resistor
CL = Load capacitance includes jig and probe capacitance
RT = Termination resistance should be equal to ZOUT
of pulse generators.
SW00047
Waveform 3. Load circuitry for switching times.
VOH
Qn OUTPUT
HIGH-to-OFF
OFF-to-HIGH
GND
tPHZ
outputs
enabled
tPZH
VY
outputs
disabled
VM
outputs
enabled
Waveform 2. 3-State enable and disable times.
SW00207
1998 May 20
6
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