2000-11-28 Page
1
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Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Applications
=
3.3V to 2.5V translation
=
2.5V to 1.8V translation
=
Hot-Swapping
=
Logic replacement
=
Memory bank, video, and audio
switching
General Description
The VS3V257 is a high-speed LVTTLcompatible Quad 2:1 multiplexer/demultiplexer. The VS3V257
contains four mux/demux channels, with a common path control (S) and active low enable (/E). The low ON
resistance of the VS3V257 allows inputs to be connected to outputs, without adding propagation delay and
without generating additional signal noise. The VS3V2257 has 25
resistors in series with the switches to
reduce ground-bounce noise and signal reflection.
The VS3V257 and VS3V2257 are designed for 3.3V to 2.5V or 2.5V to 1.8V level translation, without any
external components. These switches also offer very high impedance between switch terminals in the
power-off or "disabled" state. This feature, combined with near-zero propagation delay in the "on" state,
makes VS3V257 and VS3V2257 ideal interface elements for hot-swapping applications.
VS3V257 / VS3V2257
High-speed 3.3V CMOS VSwitch
Quad 2:1 Mux/Demux
Features
=
Enhanced N-FET with no DC path to V
CC
or GND in normal operating signal voltage
range.
=
Low impedance switches connect inputs to
outputs with near-zero propagation delay:
5
(VS3V257) and 25
(VS3V2257)
=
Pin-compatible with 74LVC257 or
equivalent logic devices
=
Zero added ground bounce or signal noise
=
Break-before-make feature
=
Undershoot clamp diodes on all switch and
control pins
=
ESD rating >2000V (Human Body Model)
=
or >200V (Machine Model)
=
Latch-up current >100mA
=
Available in 150-mil wide QSOP package
(All Pins Top View)
I0
A
I1
A
I0
B
I1
B
S
/E
Y
A
Y
B
Y
C
Y
D
I0
C
I1
C
I0
D
I1
D
I1
D
I0
D
QSOP
/E
Y
D
I0
C
I1
C
Y
C
V
CC
GND
S
I0
A
I1
A
Y
A
I0
B
I1
B
Y
B
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Figure 1. Functional Block Diagram
Figure 2. Pin Configuration
VS3V257/VS3V2257
2000-11-28 Page
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MDSS-0001-01
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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
I0
X
, I1
X
I/O
Data Input or Output
S I
Select
Input
/E I Enable
Input
Y
A
- Y
D
I/O
Data Output or Input
Table 2. Function Table
Inputs Path Function
/E S
H
X
Hi Impedance
Disable all switches
L L IO
X
<-> Y
X
Select
0
L H I1
X
<-> Y
X
Select
1
Table 3. Absolute Maximum Ratings
Supply Voltage to Ground....................................-0.5V to +4.6V
DC Switch Voltage V
S
.........................................-0.5V to +4.6V
DC Input Voltage V
IN
..........................................-0.5V to +4.6V
AC Input Voltage (Pulse Width < 20ns)...............................-3.0V
DC Output Sink Current per Switch Pin.............................128 mA
Maximum Power Dissipation.......................................0.5 Watts
Storage Temperature.......................................-65
o
C to +150
o
C
Note
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 Operation
Typ
Max
Unit
Control Inputs
4
5
pF
VSwitch Channels
Demux
5
7
pF
(Switch OFF)
Mux
7
8
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.
Table 5. Recommended Operating Conditions
Symbol Parameter Conditions
Min
Typ
Max
Units
V
CC
Power supply voltage
2.3
3.6
V
V
IL
Low level input voltage
(Control inputs)
Vcc = 2.3 to 2.7
0.7
V
Vcc =2.7 to 3.6
0.8
V
IH
High level input voltage
(Control inputs)
Vcc = 2.3 to 2.7
1.7
V
Vcc = 2.7 to 3.6
2.0
T
A
Operating free-air temperature
-40
85
o
C
Note:
All unused control inputs of the device must be held at Vcc or GND, to ensure proper device operation
VS3V257/VS3V2257
2000-11-28 Page
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MDSS-0001-01
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Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Table 6. Electrical Characteristics Over Recommended Operating Free-air Temperature Range
Symbol Parameter
Test
Conditions
Min
Typ
Max
Units
Control Inputs
-1.5
V
IK
Clamp
Voltage
Switch I/O
V
CC
= Min, I
IK
= -18 mA
-1.5
V
V
OH
Logic High Voltage
Switch I/O
V
IN
= V
CC
= 3.3V, I
OUT
= -5
A
V
IN
= V
CC
= 2.5V, I
OUT
= -5
A
2.1
1.4
2.6
1.9
V
I
I
Input Leakage Current
Control Inputs V
CC
= Max, V
I
= V
CC
or GND
1
A
Control Inputs
|
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
,
/E = V
CC
1
A
VS3V257 50
mA
I
ODL
Switch I/O Drive
Current (Logic LOW)
V
CC
= 3.0V, V
IN
= 0,
V
OUT
= 1.5V
VS3V2257 30
mA
VS3V257 -20
mA
I
ODH
Switch I/O Drive
Current (Logic HIGH)
V
CC
= 3.0V, V
IN
= V
CC
,
V
OUT
= 1.5V
VS3V2257 -10
mA
VS3V257 5
(2)
7
V
CC
= 3.0V, V
IN
= 0,
I
OUT
= 15mA
VS3V2257 20
28
(2)
40
VS3V257 10
(3)
14
R
ON
Switch
ON
Resistance
(1)
V
CC
= 2.3V, V
IN
= 0,
I
OUT
= 8mA
VS3V2257 23
35
(3)
48
Notes:
1. R
ON
is measured by forcing specified current into the `output' node of the switch with the `input' node of the switch
at the specified voltage.
2. Typical value is specified at V
CC
= 3.3V and T
A
= 25
o
C.
3. Typical value is specified at V
CC
= 2.5V and T
A
= 25
o
C.
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, S, /E = V
CC
or GND, f = 0
1
A
I
CC
Power Supply Current per Input High
(2)
(Control Inputs)
V
CC
= 3.6V, V
IN
= 3.0V, f = 0
V
CC
= 2.7V, V
IN
= 2.1V, f = 0
300
A
Q
CCD
Dynamic Power Supply Current
(3)
V
CC
= Max, Switch pins open,
Control Inputs toggling at 50% duty cycle
0.15 mA/MHz
Notes:
1. For conditions shown as Min or Max, use the appropriate values per Recommended Operating Conditions.
2. Per 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.
VS3V257/VS3V2257
2000-11-28 Page
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Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
0
1
2
3
V
IN
(V)
2
V
IN
(V)
Vcc=3.3V
Vcc=3.0V
Vcc=3.5V
3
1
V
OUT
(V)
Vcc=2.3V
Vcc=2.5V
Vcc=2.7V
3
VOLTAGE TRANSLATION
V
OH
CHARACTERISTICS
Figure 3. 3.3V to 2.5V Translation
(T
A
+ 25
C)
Figure 4. 2.5V to 1.8V Translation
(T
A
+ 25
C)
Figure 5. V
OH
CHARACTERISTICS
(Vcc = 3.3V nominal)
Supply Voltage V
CC
(V)
(T
A
+ 25
C)
V
OH
(V)
Supply Voltage V
CC
(V)
(T
A
+ 25
C)
0
1.0
2.0
3.0
2.2
2.3
2.4
2.5
2.8
2.7
2.6
Figure 6. V
OH
CHARACTERISTICS
(Vcc = 2.5V nominal)
V
OUT
(V)
1
2
4
0
1
2
3
4
V
OH
(V)
0
1.0
2.0
3.0
2.9
3.1
3.3
3.6 3.7
3.0
3.2
3.4 3.5
Vcc=3.3V
Vcc=3.0V
Vcc=3.6V
VS3V257/VS3V2257
2000-11-28 Page
5
MDSS-0001-01
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 3.3V Supply Voltage
T
A
= -40
o
C to +85
o
C, V
CC
= 3.3V + 0.3V
C
LOAD
= 30pF, R
LOAD
= 1k
unless otherwise stated.
Symbol
Description
(1)
VS3V257
Min
(3)
Max
VS3V2257
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, S to Y
X
, I0
X
, or I1
X
0.5 5.2 0.5 6.2 ns
t
PZH
, t
PZL
Switch Turn-on Delay, /E to Y
X
, I0
X
, or I1
X
0.5 4.8 0.5 5.8 ns
t
PLZ
, t
PHZ
Switch Turn-off Delay
(3)
,
S or /E to Y
X
, I0
X
, or I1
X
0.5 5.0 0.5 5.0 ns
Table 9. Switching Characteristics Over Operating Range 2.5V Supply Voltage
T
A
= -40
o
C to +85
o
C, V
CC
= 2.5V + 0.2V
C
LOAD
= 30pF, R
LOAD
= 1k
unless otherwise stated.
Symbol
Description
(1)
VS3V257
Min
(3)
Max
VS3V2257
Min
(3)
Max
Units
t
PLH
, t
PHL
Data Propagation Delay
(2,3)
through the switch
ns
t
PZH
, t
PZL
Switch Turn-on Delay, S to Y
X
, I0
X
, or I1
X
ns
t
PZH
, t
PZL
Switch Turn-on Delay, /E to Y
X
, I0
X
, or I1
X
ns
t
PLZ
, t
PHZ
Switch Turn-off Delay
(3)
,
S or /E to Y
X
, I0
X
, or I1
X
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 VS3V257 and 1.25 ns for VS3V2257. 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 7. AC Test Circuit and Switching Waveforms
AC Test Circuit
3.3V Supply Voltage
Load Switch
Position
TEST S1
t
PLH
, t
PHL
Open
t
PLZ
, t
PZL
5V
t
PHZ
, t
PZH
GND
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
1k
R
L
S
1
5 V
50
=
Coax to
Oscilloscope
50
950
R1
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