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.
GND
4
A
1
4
A
2
5
A
1
5
A
2
6
A
1
6
A
2
7
A
1
7
A
2
GND
3
B
2
4
B
1
4
B
2
5
B
1
5
B
2
6
B
1
6
B
2
7
B
1
7
B
2
8
B
1
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
3508 tbl 03
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
NOTES:
1. Capacitance is characterized but not tested
2. T
A
= 25°C, f = 1MHz, VI
N
= 0V, V
OUT
= 0V
V
CC
8
A
1
FUNCTION TABLE
S
2
L
L
L
L
H
H
H
H
S
1
L
L
H
H
L
L
H
H
S
0
L
H
L
H
L
H
L
H
A
1
Z
B
1
B
2
Z
Z
Z
B
1
B
2
A
2
Z
Z
Z
B
1
B
2
Z
B
2
B
1
Function
Disconnect
A
1
to B
1
A
1
to B
2
A
2
to B
1
A
2
to B
2
Disconnect
A
1
to B
1
, A
2
to B
2
A
1
to B
2
, A
2
to B
1
3508 tbl 04
GND
8
A
2
9
A
1
9
A
2
10
A
1
10
A
2
11
A
1
11
A
2
12
A
1
12
A
2
GND
8
B
2
9
B
1
9
B
2
10
B
1
10
B
2
11
B
1
11
B
2
12
B
1
12
B
2
SSOP/
TSSOP/TVSOP
TOP VIEW
3508 drw 02
2
IDT74FST163212
24-BIT BUS EXCHANGE SWITCH
COMMERCIAL TEMPERATURE RANGE
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Commercial: T
A
= –40°C to +85°C, V
CC
= 5.0V
±10%
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
= Max., V
O
= GND
(3)
V
CC
= Min., I
IN
= –18mA
V
CC
= Min. V
IN
= 0.0V
I
ON
= 64mA
V
CC
= Min. V
IN
= 0.0V
I
ON
= 30mA
V
CC
= Min. V
IN
= 2.4V
I
ON
= 15mA
I
OFF
I
CC
Input/Output Power Off Leakage
Quiescent Power Supply Current
V
CC
= 0V, V
IN
or V
O
≤
4.5V
V
CC
= Max., V
IN
= GND or V
CC
—
—
—
0.1
±1
3
µA
µA
3508 tbl 05
Test Conditions
(1)
Guaranteed Logic HIGH for Control Inputs
Guaranteed Logic LOW for Control Inputs
V
CC
= Max.
V
CC
= Max.
V
I
= V
CC
V
I
= GND
V
O
= V
CC
V
O
= GND
Min.
2.0
—
—
—
—
—
—
—
—
—
—
Typ.
(2)
—
—
—
—
—
—
300
–0.7
4
4
10
Max.
—
0.8
±1
±1
±1
±1
—
–1.2
7
7
15
Unit
V
V
µA
µA
mA
V
Ω
Ω
Ω
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.
3
IDT74FST163212
24-BIT BUS EXCHANGE SWITCH
COMMERCIAL TEMPERATURE RANGE
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 Pins Toggling
(24 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
—
7.2
9.6
—
7.7
11.1
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 fi
All currents are in milliamps and all frequencies are in megahertz.
3508 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
±10%
Symbol
t
PLH
t
PHL
t
BX
t
PZH
t
PZL
t
PHZ
t
PLZ
|Q
CI
|
|Q
DCI
|
Description
Data Propagation Delay
A to B, B to A
(3,4)
Switch Multiplex Delay
S to A, B
Switch Turn on Delay
S to A, B
Switch Turn off Delay
S to A, B
(3)
Charge Injection, Typical
(5,7)
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
6.5
6.5
7
—
—
Unit
ns
ns
ns
ns
pC
3508 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 2.5ns for 50pF 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 on 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.- A
1
to B
1
= >A
1
to B
2
), 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 A
1
to B
1
switch is compensated by the turn on of the A
1
to B
2
switch.
7. Characterized parameter. Not 100% tested.
4
IDT74FST163212
24-BIT BUS EXCHANGE SWITCH
COMMERCIAL TEMPERATURE RANGE
TEST CIRCUITS AND WAVEFORMS
TEST CIRCUITS FOR ALL OUTPUTS
V
CC
500Ω
V
IN
Pulse
Generator
R
T
D.U.T.
50pF
C
L
3508 lnk 03
SWITCH POSITION
7.0V
Test
Open Drain
Disable Low
Enable Low
All Other Tests
Switch
Closed
Open
V
OUT
500Ω
3508 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.
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
3508 lnk 04
PULSE WIDTH
t
H
LOW-HIGH-LOW
PULSE
t
W
HIGH-LOW-HIGH
PULSE
1.5V
t
REM
1.5V
t
SU
t
H
3508 lnk 05
PROPAGATION DELAY
3V
1.5V
0V
V
OH
1.5V
V
OL
3V
1.5V
0V
3508 lnk 06
ENABLE AND DISABLE TIMES
ENABLE
DISABLE
3V
CONTROL
INPUT
t
PZL
OUTPUT
NORMALLY
LOW
OUTPUT
NORMALLY
HIGH
SWITCH
CLOSED
t
PZH
SWITCH
OPEN
1.5V
0V
0V
3508 lnk 07
SAME PHASE
INPUT TRANSITION
t
PLH
OUTPUT
t
PLH
OPPOSITE PHASE
INPUT TRANSITION
t
PHL
t
PHL
t
PLZ
3.5V
1.5V
t
PHZ
0.3V
1.5V
0V
3.5V
0.3V
V
OL
V
OH
NOTES:
1. Diagram shown for input Control Enable-LOW and input Control Disable-
白光LED光衰原因之荧光粉性能的衰退 到目前,白光 LED、尤其是小功率白光 LED 的发光性能快速衰退已越来越为人们所认识。其实,盲目地夸大宣传,只能将 LED 行业引向歧途,不正视白光 LED 存在的问题,只能延缓白光 LED 应用的发展。只有正视问题、研究问题、尽早解决问题,白光 LED 才能健康、快速发展。 白光 LED 当前面临的一个主要问题就寿命问题。由于白光 LED 的价格尚很...[详细]