2001-04-12 Page
1
MDSS-0008-02
www.vishali.com
Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Applications
=
5V to 3.3V translation in mixed-supply environment
=
Hot-swap interface
=
Logic replacement
=
Bus isolation
General Description
The VS3244 and VS32244 are high-speed TTLcompatible dual 4-bit bus switches. The VS3244 contains
two banks of 4-bit switches, with one common active low enable (/G) per bank. The low ON resistance of the
VS3244 allows inputs to be connected to outputs, without adding propagation delay and without generating
additional signal noise. The VS32244 has 25
resistors in series with the switches to reduce ground-bounce
noise and signal reflection.
The VS3244 and VS32244 bus switches are function and pinout compatible with QS3244 and CBT3244
switches. They enable 5V to 3.3V translation when used with a diode in the power supply line. In addition,
the high off-isolation in the `disable' mode makes VS3244 and VS32244 ideal interface elements for hot-swap
applications.
Figure 1. Functional Block Diagram Figure 2. Pin Configuration
(All Pins Top View)
VS3244 / VS32244
High Speed CMOS VSwitch
Dual 4-Bit Bus Switches
Features
=
Enhanced N-FET with no DC path to V
CC
or GND in normal operating signal voltage
range.
=
Low impedance bidirectional data flow:
5
(VS3244) and 25
(VS32244)
=
Pin-compatible with QS3244 and CBT3244
switches.
=
Near-zero propagation delay
=
Zero added ground bounce or signal noise
=
TTL-compatible control signals
=
Undershoot clamp diodes on all switch and
control pins
=
ESD rating >2000V (Human Body Model)
or >200V (Machine Model)
=
Latch-up current >100mA
=
Available- Available in 150-mil wide QSOP
package
QSOP
A0
2A3
2A4
1B4
1B1
1B2
/1G
1B3
1A1
1A2
1A3
1B4
1A4
2B1
2B2
/2G
2B3
2A1
2A2
2A3
2B4
2A4
GND
V
CC
1
2
3
4
8
5
6
7
9
10
20
19
18
17
16
15
14
13
12
11
/2G
1B1
1B2
1B3
2A2
2A1
/1G
1A1
2B4
2B3
1A2
1A3
2B2
1A4
2B1
VS3244/VS32244
2001-04-12 Page
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MDSS-0008-02
www.vaishali.com
Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Table 1. Pin Description
Name I/O Description
1A1 1A4
2A1 2A4
I/O
Data Input or Output
/1G, /2G
I
Enable Input
1B1 1B4
2B1 2B4
I/O
Data Output or Input
Table 2. Function Table ( Each 4-bit bus switch)
Input Path
Function
/nG
H
Hi Impedance
Disable all switches
L
Switch Closed
A port = B port
Table 3. Absolute Maximum Ratings
Supply Voltage to Ground....................................-0.5V to +7.0V
DC Switch Voltage V
S
.........................................-0.5V to +7.0V
DC Input Voltage V
IN
....................................... ...-0.5V to +7.0V
AC Input Voltage (Pulse Width < 20ns)...............................-3.0V
DC Output Sink Current per Switch Pin.............................120 mA
Maximum Power Dissipation.......................................0.5 Watts
Storage Temperature.......................................-65
o
C to +150
o
C
ABSOLUTE MAXIMUM CONTINUOUS RATINGS are those values beyond which damage to the device may occur.
Exposure to these conditions or conditions beyond those indicated may adversely affect device reliability.
Correct functional operation while operating in the absolute maximum rated conditions is not implied.
Table 4. Capacitance
T
A
= 25
o
C, f = 1 MHz, V
IN
= 0V, V
OUT
= 0V
QSOP
Pins Typ
Max
Unit
Control Inputs
4
5
pF
VSwitch Channels
(Switch OFF)
5
7
pF
Note
Capacitance is guaranteed, but not production tested. Total capacitance of a path, when the switch is closed, is
the sum of the switch terminal capacitances.
VS3244/VS32244
2001-04-12 Page
3
MDSS-0008-02
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Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Table 5. Recommended Operating Conditions
Symbol Parameter Conditions
Min
Typ
Max
Units
V
CC
Power supply voltage
4.5
5.5
V
V
IL
Low level input voltage
-0.5
0.8
V
V
IH
High level input voltage
2.0
5.5
V
T
A
Operating free-air temperature
-40
85
o
C
Table 6. Electrical Characteristics Over Recommended Operating Free-air Temperature Range
Symbol Parameter
Test
Conditions
Min
Typ
(1)
Max Units
Control Input
-1.5
V
IK
Clamp
Voltage
Switch I/O
V
CC
= Min, I
IK
= -18 mA
-1.5
V
V
IN
= V
CC
= 5V, I
OUT
= -5
A
3.7 3.9 4.1
V
OH
Logic High Voltage
Switch I/O
V
CC
= 4.3V, V
N
= 5V,
I
OUT
= -5
A
3.0 3.3 3.6
V
I
I
Input Leakage
Current
Control Input
V
CC
= Max, V
I
= V
CC
or GND
1
A
Control Input
|
OFF
|
Power OFF Leakage
Current
Switch I/O
V
CC
= 0,
V
I
or V
O
= V
CC
or GND
1
A
|I
OZ
|
OFF State Leakage
Current
Switch I/O
V
CC
= Max, V
I/O
= V
CC
,
/1G, /2G = V
CC
1
A
VS3244 50
mA
I
ODL
Switch I/O Drive
Current (Logic LOW)
V
CC
= Min, V
IN
= 0,
V
OUT
= 0.4V
VS32244
mA
VS3244 -50
mA
I
ODH
Switch I/O Drive
Current (Logic HIGH)
V
CC
= Min, V
IN
= V
CC
,
V
OUT
= 2.4V
VS32244
mA
VS3244
5
7
R
ON
Switch
ON
Resistance
(2)
V
CC
= Min, V
IN
= 0,
I
OUT
= 30mA
VS32244 20
28
40
Notes:
1. Typical values are specified at V
CC
= 5.0V and T
A
= 25
o
C.
2. R
ON
is measured by forcing specified current into the `output' node of the switch with the `input' node of the switch at the the
specified voltage
Table 7. Power Supply Characteristics Over Recommended Operating Free-air Temperature Range
Symbol Parameter
Test
Conditions
(1)
Max
Units
I
CCQ
Quiescent Power Supply Current
V
CC
= Max, /1G, /2G = V
CC
or GND, f = 0
1
A
I
CC
Power Supply Current per Input High
(Control Input)
(2)
V
CC
= Max, V
IN
= 3.4V, f = 0
1.5
mA
Q
CCD
Dynamic Power Supply Current
(3)
V
CC
= Max, Switch pins open,
Control Inputs toggling at 50% duty cycle
0.25 mA/MHz
Notes:
1. For conditions shown as Min or Max, use the appropriate values per Recommended Operating Conditions.
2. Per TTL-driven control input. All other control inputs at GND. Switch I/O pins do not contribute to
ICC.
3. This parameter represents the average DC current resulting from the switching of internal nodes of the device at a given
frequency. The switch I/O pins make insignificant contribution to the dynamic power supply current of the device. This parameter
is guaranteed, but not production tested.
VS3244/VS32244
2001-04-12 Page
4
MDSS-0008-02
www.vaishali.com
Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Figure 3. VOLTAGE TRANSLATION
Figure 5. Voltage Translation Application
V
CC
1N4148
or equivalent
10K
V
CC
= 5V
/1G, /2G
I/O
VS3244
VS32244
3.3V
DEVICE
5V
DEVICE
I/O
Figure 4. VOH CHARACTERISTICS
3
4
5
Vout
(V)
0
1
2
Vin (V)
4 5
3
2
1
0
VCC = 4.3V
VCC Supply Voltage (V)
2.0
2.5
5.5
5.0
4.5
3.5
3.0
4.0
4.5
4.75 5.25
TA = 85
C
TA = 25
C
TA = - 40
C
VOH
Output Voltage
(V)
VS3244/VS32244
2001-04-12 Page
5
MDSS-0008-02
www.vaishali.com
Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Table 8. Switching Characteristics Over Operating Range
T
A
= -40
o
C to +85
o
C, V
CC
= 5.0V + 10
%
C
LOAD
= 50pF, R
LOAD
= 500
unless otherwise stated.
Symbol
Description
(1)
VS3245
Min
(3)
Max
VS32245
Min
(3)
Max
Units
t
PLH
, t
PHL
Data Propagation Delay
(2,3)
through the switch
0.25
1.25
ns
t
PZH
, t
PZL
Switch Turn-on Delay, /1G, /2G to A or B
0.5
5.6
0.5
6.6
ns
t
PLZ
, t
PHZ
Switch Turn-off Delay /1G, /2G to A or B
0.5
4.5
0.5
4.5
ns
Notes:
1. See test circuits and waveforms.
2. This parameter is the calculated theoretical RC time constant of ON-state resistance of the switch and the specified load
capacitance when driven by an ideal voltage source (zero source impedance). This time-constant is on the order of 0.25 ns for
VS3244 and 1.25 ns for VS32244. Since this time-constant is much smaller than rise/fall times of typical driving signals, it adds
very little propagation delay to the system.
3. This parameter is guaranteed, but not production tested.
Figure 5. AC Test Circuit and Switching Waveforms
AC Test Circuit
Load Switch
Position
TEST S1
t
PLH
, t
PHL
Open
t
PLZ
, t
PZL
Closed
t
PHZ
, t
PZH
Open
Input Conditions
Input voltage = 0 V to 3.0 V
t
r
= t
f
= 2.5ns (10% to 90%)
Pulse
Generator
DUT
V
IN
V
OUT
C
L
500
R
L
S
1
7 V
50
=
Coax to
Oscilloscope
50
450
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