Enhanced N channel FET with no inherent diode to Vcc
25Ω bidirectional switches connect inputs to outputs
Ω
Pin compatible with 74F244, 74FCT244, and 74FCT244T
Zero propagation delay, zero ground bounce
Undershoot clamp diodes on all switch and control inputs
Available in QSOP, SOIC, and TSSOP packages
APPLICATIONS:
•
•
•
•
•
•
•
The QS3244 provides a set of eight high-speed CMOS TTL-compatible
bus switches in a pinout compatible with 74FCT244, 74F244, 74ALS/AS/
LS244 8-bit drivers. The low ON resistance (5Ω) of the 3244 allows inputs
to be connected to outputs without adding propagation delay and without
generating additional ground bounce noise. The two enable (xG) signals
turn the switches on similar to the
xG
signals of the 74’244.
QuickSwitch devices provide an order of magnitude faster speed than
conventional logic devices.
The QS3244 is characterized for operation at -40°C to +85°C.
DESCRIPTION:
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
1G
1A
1
1A
2
1A
3
1A
4
1Y
1
1Y
2
1Y
3
1Y
4
2G
2A
1
2A
2
2A
3
2A
4
2Y
1
2Y
2
2Y
3
2Y
4
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
INDUSTRIAL TEMPERATURE RANGE
1
c
1999 Integrated Device Technology, Inc.
DECEMBER 1999
DSC-5722/2
IDTQS3244
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
1G
1A
1
2Y
4
1A
2
2Y
3
1A
3
2Y
2
1A
4
2Y
1
G ND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
CC
2G
1Y
1
2A
4
1Y
2
2A
3
1Y
3
2A
2
1Y
4
2A
1
V
TERM
(3)
V
AC
I
OUT
P
MAX
T
STG
NOTES:
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. V
CC
terminals.
3. All terminals except V
CC
.
CAPACITANCE
(T
A
= +25°C, f = 1MHz, V
IN
= 0V, V
OUT
= 0V)
Pins
Control Inputs
Quickswitch Channels (Switch OFF)
Typ.
3
5
Max.
(1)
5
7
Unit
pF
pF
QSOP/ SOIC/ TSSOP
TOP VIEW
NOTE:
1. This parameter is guaranteed but not production tested.
PIN DESCRIPTION
Pin Names
1G, 2G
Ax, Yx
Output Enable
Data I/Os
Description
FUNCTION TABLE
(1)
1G
H
L
H
L
2G
H
H
L
L
1A, 1Y I/Os
Disconnected
1Ax = 1Yx
Disconnected
1Ax = 1Yx
2A, 2Y I/Os
Disconnected
Disconnected
2Ax = 2Yx
2Ax = 2Yx
NOTE:
1. H = HIGH Voltage Level
L = LOW Voltage Level
2
IDTQS3244
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
= 5V ± 5%
Symbol
V
IH
V
IL
I
IN
I
OZ
R
ON
V
P
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Leakage Current (Control Inputs)
Off-State Current (Hi-Z)
Switch ON Resistance
Pass Voltage
(2)
Test Conditions
Guaranteed Logic HIGH for Control Inputs
Guaranteed Logic LOW for Control Inputs
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)
Max.
—
—
—
—
5
10
4
—
0.8
±1
±1
7
12
4.2
V
Unit
V
V
µA
µA
Ω
NOTES:
1. Typical values are at V
CC
= 5V and 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
IDTQS3244
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 V
CC
, f = 0
V
CC
= Max., V
IN
= 3.4V, f = 0
V
CC
= Max., A and Y Pins Open, Control Inputs Toggling @ 50% Duty Cycle
Max.
3
2.5
0.25
Unit
µA
mA
mA/MHz
NOTES:
1. For conditions shown as Min. or Max., use the appropriate values specified under DC Electrical Characteristics.
2. Per TTL-driven input (V
IN
= 3.4V, control inputs only). A and Y 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 Y inputs generate no significant
AC or DC currents as they transition. This parameter is guaranteed but not production tested.
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
T
A
= -40°C to +85°C, V
CC
= 5V ± 5%
C
LOAD
= 50pF, R
LOAD
= 500Ω unless otherwise noted.
Symbol
t
PLH
t
PHL
t
PZL
t
PZH
t
PLZ
t
PHZ
Parameter
Data Propagation Delay
(2)
Ax to Yx
Switch Turn-On Delay
1G, 2G
to Yx
Switch Turn-Off Delay
(2)
1G, 2G
to Yx
Min
.
(1)
0.5
0.5
Typ.
Max.
0.25
(3)
5.6
5.2
Unit
ns
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 at 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 on
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