1. Stresses greater than those listed under ABSOLUTE MAXIMUM RAT-
INGS may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions
above those indicated in the operational sections of this specification is
not implied. Exposure to absolute maximum rating condiitions for
extended periods may affect reliability.
NOTE:
1. H = HIGH Voltage Level
L = LOW Voltage Level
X = Don't Care
Z = High Impedance
2. V
CC
, Control and Switch terminals.
CAPACITANCE
(1)
Symbol
C
IN
C
I/O
Parameter
Control Input Capacitance
Switch Input/Output
Capacitance
Switch Off
Conditions
(2)
Typ. Unit
4
pF
pF
3257 tbl 04
NOTES:
1. Capacitance is characterized but not tested
2. T
A
= 25°C, f = 1MHz, VI
N
= 0V, V
OUT
= 0V
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Commercial: T
A
= –40°C to +85°C, V
CC
= 5.0V
±5%
Symbol
V
IH
V
IL
I
I H
I
I L
I
OZH
I
OZL
I
OS
V
IK
R
ON
Parameter
Input HIGH Voltage
Input LOW Voltage
Input HIGH Current
Input LOW Voltage
High Impedance Output Current
(3-State Output pins)
Short Circuit Current
Clamp Diode Voltage
Switch On Resistance
(4)
V
CC
= Min., I
IN
= –18mA
V
CC
= Min., V
IN
= 0.0V,
I
ON
= 30mA
V
CC
= Min., V
IN
= 2.4V,
I
ON
= 15mA
V
CC
= 0V, V
IN
or V
O
≤
4.5V
V
CC
= Max., V
I
= GND or V
CC
V
CC
= Max.
Test Conditions
(1)
Guaranteed Logic HIGH for Control Inputs
Guaranteed Logic LOW for Control Inputs
V
CC
= Max.
V
I
= V
CC
V
I
= GND
V
O
= V
CC
V
O
= GND
V
CC
= Max., V
O
= GND
(3)
Min.
2.0
—
—
—
—
—
—
—
—
—
—
—
Typ.
(2)
—
—
—
—
—
—
300
–
0.7
Max.
—
0.8
±1
±1
±1
±1
—
–
1.2
Unit
V
V
µA
µA
mA
V
Ω
Ω
µA
µA
3257 tbl 05
5
10
—
0.1
7
15
±1
3
I
OFF
I
CC
Input/Output Power Off Leakage
Quiescent Power Supply Current
NOTES:
1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at V
CC
= 5.0V, +25°C ambient.
3. Not more than one output should be tested at one time. Duration of the test should not exceed one second.
4. Measured by voltage drop between ports at indicated current through the switch.
10.3
2
IDT54/74FST3257
QUAD 2:1 MUX/DEMUX BUS SWITCH
COMMERCIAL TEMPERATURE RANGES
POWER SUPPLY CHARACTERISTICS
Symbol
∆I
CC
I
CCD
Parameter
Quiescent Power Supply Current
TTL Inputs HIGH
Dynamic Power Supply
Current
(4)
Test Conditions
(1)
V
CC
= Max.
V
IN
= 3.4V
(3)
V
CC
= Max.
Outputs Open
Enable Pin Toggling
50% Duty Cycle
V
CC
= Max.
Outputs Open
Enable Pin Toggling
(4 Switches Toggling)
fi = 10MHz
50% Duty Cycle
Min.
—
—
Typ.
(2)
0.5
30
Max.
1.5
40
Unit
mA
µA/
MHz/
Switch
mA
V
IN
= V
CC
V
IN
= GND
I
C
Total Power Supply Current
(6)
V
IN
= V
CC
V
IN
= GND
V
IN
= 3.4
V
IN
= GND
—
1.2
1.6
—
1.5
2.4
NOTES:
1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at V
CC
= 5.0V, +25°C ambient.
3. Per TTL driven input (V
IN
= 3.4V). All other inputs at V
CC
or GND.
4. This parameter is not directly testable, but is derived for use in Total Power Supply Calculations.
5. Values for these conditions are examples of the I
CC
formula. These limits are guaranteed but not tested.
6. I
C
= I
QUIESCENT
+ I
INPUTS
+ I
DYNAMIC
I
C
= I
CC
+
∆I
CC
D
H
N
T
+ I
CCD
(f
i
N)
I
CC
= Quiescent Current
∆I
CC
= Power Supply Current for a TTL High Input (V
IN
= 3.4V)
D
H
= Duty Cycle for TTL Inputs High
N
T
= Number of TTL Inputs at D
H
I
CCD
= Dynamic Current Caused by an Input Transition Pair (HLH or LHL)
f
i
= Input Frequency
N = Number of Switches Toggling at f
i
All currents are in milliamps and all frequencies are in megahertz.
3257 tbl 06
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Commercial: T
A
= –40°C to +85°C, V
CC
= 5.0V
±5%
Symbol
t
PLH
t
PHL
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
|Q
CI
|
|Q
CDI
|
Description
Data Propagation Delay
I to Z, Z to I
(3,4)
Switch Multiplex Delay
S to I, Z
Switch Turn on Delay
E
to I, Z
Switch Turn off Delay
E
to I, Z
(3)
Charge Injection, Typical
(5,6)
Charge Injection, Typical
(6,7)
Condition
(1)
C
L
= 50pF
R
L
= 500Ω
Min.
(2)
—
1.5
1.5
1.5
—
—
Typ.
—
—
—
—
1.5
0.5
Max.
0.25
5.2
4.8
5.0
—
—
Unit
ns
ns
ns
ns
pC
pC
3257 tbl 07
NOTES:
1. See test circuit and waveforms.
2. Minimum limits guaranteed but not tested.
3. This parameter is guaranteed by design but not tested.
4. The bus switch contributes no propagation delay other than the RC delay of the on resistance of the switch and the load capacitance. The time constant
for the switch alone is of the order of 0.25 ns for 50 pF load. Since this time is constant and much smaller than the rise/fall times of typical driving signals,
it adds very little propagation delay to the system. Propagation delay of the bus switch when used in a system is determined by the driving circuit on the
driving side of the switch and its interaction with the load on the driven side.
5. Measured at switch turn off, load = 50 pF in parallel with 10 mΩ scope probe, V
IN
= 0.0 volts.
6. Measured at switch turn off through bus multiplexer, (e.g.- I
0
to Z = > I
1
to Z), load = 50 pF in parallel with 10 MΩ scope probe, V
IN
at A = 0.0 volts. Charge
injection is reduced because the injection from the turn off of the I
0
to Z switch is compensated by the turn on of the I
1
to Z switch.
7. Characterized parameter. Not 100% tested.
10.3
3
IDT74FST3257
QUAD 2:1 MUX/DEMUX BUS SWITCH
COMMERCIAL TEMPERATURE RANGES
TEST CIRCUITS AND WAVEFORMS
TEST CIRCUITS FOR ALL OUTPUTS
V
CC
500Ω
V
IN
Pulse
Generator
R
T
D.U.T.
50pF
C
L
500Ω
V
OUT
7.0V
SWITCH POSITION
Test
Open Drain
Disable Low
Enable Low
All Other Tests
Open
3257 lnk 08
DEFINITIONS:
C
L
= Load capacitance: includes jig and probe capacitance.
R
T
=
Termination resistance: should be equal to Z
OUT
of the Pulse
Generator.
Switch
Closed
3257 lnk 03
SET-UP, HOLD AND RELEASE TIMES
DATA
INPUT
TIMING
INPUT
ASYNCHRONOUS CONTROL
PRESET
CLEAR
ETC.
SYNCHRONOUS CONTROL
PRESET
CLEAR
CLOCK ENABLE
ETC.
t
SU
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
3257 lnk 04
PULSE WIDTH
t
H
LOW-HIGH-LOW
PULSE
t
W
HIGH-LOW-HIGH
PULSE
1.5V
t
REM
1.5V
3257 lnk 03
t
SU
t
H
PROPAGATION DELAY
SAME PHASE
INPUT TRANSITION
t
PLH
OUTPUT
t
PLH
OPPOSITE PHASE
INPUT TRANSITION
t
PHL
t
PHL
3V
1.5V
0V
V
OH
1.5V
V
OL
3V
1.5V
0V
3257 lnk 06
ENABLE AND DISABLE TIMES
ENABLE
CONTROL
INPUT
t
PZL
OUTPUT
NORMALLY
LOW
OUTPUT
NORMALLY
HIGH
SWITCH
CLOSED
t
PZH
SWITCH
OPEN
1.5V
0V
0V
3257 lnk 07
DISABLE
3V
1.5V
0V
3.5V
0.3V
t
PHZ
0.3V
V
OH
V
OL
t
PLZ
3.5V
1.5V
NOTES:
1. Diagram shown for input Control Enable-LOW and input Control Disable-
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