Enhanced N channel FET with no inherent diode to Vcc
5Ω bidirectional switches connect inputs to outputs
Ω
Pin compatible with the 74F245, 74FCT245, and 74FCT245T
Low power CMOS proprietary technology
Zero propagation delay, zero ground bounce
Undershoot clamp diodes on all switch and control inputs
TTL-compatible control inputs
Available in SOIC, QSOP, and TSSOP packages
The QS3245 provides a set of eight high-speed CMOS TTL-compatible
bus switches in a pinout compatible with 74FCT245, 74F245, 74ALS/AS/
LS245 8-bit transceivers. The low ON resistance of the QS3245 allows
inputs to be connected to outputs without adding propagation delay and
without generating additional ground bounce noise. The Output Enable
(OE) signal turns the switches on similar to the
OE
signal of the 74’245.
QuickSwitch devices provide an order of magnitude faster speed than
conventional logic devices.
The QS3245 is characterized for operation at -40°C to +85°C.
APPLICATIONS:
•
•
•
•
•
•
•
Hot-swapping, hot-docking
Voltage translation (5V to 3.3V)
Power conservation
Capacitance reduction and isolation
Logic replacement (data processing)
Clock gating
Bus switching and isolation
FUNCTIONAL BLOCK DIAGRAM
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
OE
B
0
B
1
B
2
B
3
B
4
B
5
B
6
B
7
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
INDUSTRIAL TEMPERATURE RANGE
1
c
2000 Integrated Device Technology, Inc.
APRIL 2000
DSC-5753/1
IDTQS3245
HIGH-SPEED CMOS QUICKSWITCH 8-BIT BUS SWITCH
INDUSTRIAL TEMPERATURE RANGE
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
TERM
(2)
V
TERM
(3)
Description
Supply Voltage to Ground
DC Switch Voltage Vs
DC Input Voltage V
IN
AC Input Voltage (pulse width
≤
20ns)
DC Output Current
Maximum Power Dissipation (T
A
= 85°C)
Storage Temperature
Max
–0.5 to +7
–0.5 to +7
–0.5 to +7
–3
120
0.5
–65 to +150
Unit
V
V
V
V
mA
W
°C
NC
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
GND
1
2
3
4
5
6
7
8
9
1
0
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
V
CC
OE
B
0
B
1
B
2
B
3
B
4
B
5
B
6
B
7
V
TERM
(3)
V
AC
I
OUT
P
MAX
T
STG
NOTE:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS 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
conditions for extended periods may affect reliability.
2. Vcc terminals.
3. All terminals except Vcc.
CAPACITANCE
Pins
Control Pins
(T
A
= +25°C, f = 1.0MH
Z
, V
IN
= 0V, V
OUT
= 0V)
SOIC/ QSOP/ TSSOP
TOP VIEW
Typ.
3
5
Max.
(1)
5
7
Unit
pF
pF
Quickswitch Channels (Switch OFF)
NOTE:
1. This parameter is measured at characterization but not tested.
PIN DESCRIPTION
Pin Names
OE
Ax
Bx
Output Enable
Data I/Os
Data I/Os
Description
FUNCTION TABLE
(1)
OE
H
L
NOTE:
1. H = HIGH Voltage Level
L = LOW Voltage Level
Outputs
Disconnected
Ax = Bx
2
IDTQS3245
HIGH-SPEED CMOS QUICKSWITCH 8-BIT BUS SWITCH
INDUSTRIAL TEMPERATURE RANGE
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Industrial: T
A
= –40°C to +85°C, V
CC
= 5.0V ±5%
Symbol
V
IH
V
IL
I
IN
I
OZ
R
ON
V
P
Parameter
Input HIGH Level
Input LOW Level
Input LeakageCurrent (Control Inputs)
Off-State Output Current (Hi-Z)
Switch ON Resistance
Pass Voltage
(2)
Test Conditions
Guaranteed Logic HIGH for Control Pins
Guaranteed Logic LOW for Control Pins
0V
≤
V
IN
≤
V
CC
0V
≤
V
OUT
≤
V
CC
, Switches OFF
V
CC
= Min., V
IN
= 0V, I
ON
= 30mA
V
CC
= Min., V
IN
= 2.4V, I
ON
=15mA
V
IN
= V
CC
= 5V, I
OUT
= -5µA
Min.
2
—
—
—
—
—
3.7
Typ.
(1)
—
—
—
±0.001
5
10
4
Max.
—
0.8
±1
±1
7
15
4.2
Unit
V
V
µA
µA
Ω
V
NOTES:
1. Typical values are at V
CC
= 5.0V, T
A
= 25°C.
2. Pass Voltage is guaranteed but not production tested.
TYPICAL ON RESISTANCE vs V
IN
AT V
CC
= 5V
16
R
ON
(ohms)
14
12
10
8
6
4
2
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
V
IN
(Volts)
3
IDTQS3245
HIGH-SPEED CMOS QUICKSWITCH 8-BIT BUS SWITCH
INDUSTRIAL TEMPERATURE RANGE
POWER SUPPLY CHARACTERISTICS
Symbol
I
CCQ
∆I
CC
I
CCD
Parameter
Quiescent Power Supply Current
Power Supply Current per Control Input HIGH
(2)
Dynamic Power Supply Current per MHz
(3)
Test Conditions
(1)
V
CC
= Max., V
IN
= GND or Vcc, f = 0
V
CC
= Max., V
IN
= 3.4V, f = 0
V
CC
= Max., A and B pins open
Control Inputs Toggling at 50% Duty Cycle
NOTES:
1. For conditions shown as Min. or Max., use the appropriate values specified under DC Electrical Characteristics.
2. Per TLL driven input (V
IN
= 3.4V, control inputs only). A and B pins do not contribute to
∆Icc.
3. This current applies to the control inputs only and represents the current required to switch internal capacitance at the specified frequency. The A and B inputs generate no significant
AC or DC currents as they transition. This parameter is guaranteed but not production tested.
Max.
3
1.5
0.25
Unit
µA
mA
mA/MHz
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
T
A
= -40°C to +85°C, V
CC
= 5.0V ± 5%;
C
LOAD
= 50pF, R
LOAD
= 500Ω unless otherwise noted.
Symbol
t
PLH
t
PHL
t
PZL
t
PZH
t
PLZ
t
PHZ
Data Propagation Delay
(2,3)
An to/from Bn
Switch Turn-on Delay
OE
to Ax/Bx
Switch Turn-off Delay
(2)
OE
to Ax/Bx
0.5
—
4.5
ns
Parameter
Min.
(1)
—
0.5
Typ.
—
—
Max.
0.25
5.6
Unit
ns
ns
NOTES:
1.
Minimums are guaranteed but not production tested.
2.
This parameter is guaranteed but not production tested.
3.
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 0.25ns for C
L
= 50pF. Since this time constant is much smaller than the rise and 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
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