VS3245 / VS32245
High Speed CMOS VSwitch
8-Bit Bus Switches
Applications
•=
•=
5V to 3.3V translation in mixed-supply environment
Hot-swap interface
•=
•=
Logic replacement
Bus isolation
General Description
The VS3245 and VS32245 are high-speed TTL–compatible 8-bit bus switches. The VS3245 contains eight
high-speed bus switches, with a common active low enable (/OE). The low ON resistance of the VS3245
allows inputs to be connected to outputs, without adding propagation delay and without generating additional
signal noise. The VS32245 has 25Ω resistors in series with the switches to reduce ground-bounce noise and
signal reflection.
The VS3245 and VS32245 bus switches are function and pinout compatible with QS3245 and CBT3245
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 VS3245 and VS32245 ideal interface elements for hot-swap
applications.
Features
•=
Enhanced N-FET with no DC path to V
CC
or GND in normal operating signal voltage
range.
Low impedance bidirectional data flow:
5Ω (VS3245) and 25Ω (VS32245)
Pin-compatible with QS3245 and CBT3245
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 in 150-mil wide QSOP package
•=
•=
•=
Figure 1. Functional Block Diagram
Figure 2. Pin Configuration
(All Pins Top View)
A0
A1
A2
A3
A4
A5
A6
A7
NC
A0
A1
A2
1
2
3
4
5
6
7
8
9
QSOP
20
19
18
17
16
15
14
13
12
11
V
CC
/OE
B0
B1
B2
B3
B4
B5
B6
B7
/OE
A3
A4
A5
A6
A7
GND
10
B0
B1
B2
B3
B4
B5
B6
B7
2001-04-12
Vaishali Semiconductor
Page 1
www.vaishali.com
747 Camden Avenue, Suite C Campbell CA 95008
MDSS-0007-02
Ph. 408.377.6060
Fax 408.377.6063
VS3245/VS32245
Table 1. Pin Description
Name
A
0
- A
7
/OE
B
0
– B
7
I
I/O
I/O
I/O
Description
Data Input or Output
Enable Input
Data Output or Input
Table 2. Function Table
Input
/OE
H
L
Hi Impedance
A
n
<-> B
n
Disable all switches
A
n
= B
n
Path
Function
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 C to +150 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.
o
o
Table 4. Capacitance
T
A
= 25 C, f = 1 MHz, V
IN
= 0V, V
OUT
= 0V
o
QSOP
Pins
Control Inputs
VSwitch Channels
(Switch OFF)
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.
Typ
4
5
Max
5
7
Unit
pF
pF
2001-04-12
Vaishali Semiconductor
Page 2
www.vaishali.com
747 Camden Avenue, Suite C Campbell CA 95008
MDSS-0007-02
Ph. 408.377.6060
Fax 408.377.6063
VS3245/VS32245
Table 5. Recommended Operating Conditions
Symbol
V
CC
V
IL
V
IH
T
A
Parameter
Power supply voltage
Low level input voltage
High level input voltage
Operating free-air temperature
Conditions
Min
4.5
-0.5
2.0
-40
Typ
Max
5.5
0.8
5.5
85
V
V
V
o
Units
C
Table 6. Electrical Characteristics Over Recommended Operating Free-air Temperature Range
Symbol
V
IK
V
OH
Parameter
Clamp Voltage
Logic High Voltage
Control Input
Switch I/O
Switch I/O
Test Conditions
V
CC
= Min, I
IK
= -18 mA
V
IN
= V
CC
= 5V, I
OUT
= -5µA
V
CC
= 4.3V, V
N
= 5V,
I
OUT
= -5µA
Min
Typ
(1)
Max
-1.5
-1.5
Units
V
V
3.7
3.0
3.9
3.3
4.1
3.6
1
1
1
I
I
|
OFF
|
|I
OZ
|
I
ODL
I
ODH
R
ON
Input Leakage
Current
Power OFF Leakage
Current
OFF State Leakage
Current
Switch I/O Drive
Current (Logic LOW)
Switch I/O Drive
Current (Logic HIGH)
Switch ON
(2)
Resistance
Control Input
Control Input
Switch I/O
Switch I/O
V
CC
= Max, V
I
= V
CC
or GND
V
CC
= 0,
V
I
or V
O
= V
CC
or GND
V
CC
= Max, V
I/O
= V
CC
,
/OE = V
CC
VS3245
VS32245
VS3245
VS32245
VS3245
VS32245
20
5
28
-50
50
µA
µA
µA
mA
mA
mA
mA
V
CC
= Min, V
IN
= 0,
V
OUT
= 0.4V
V
CC
= Min, V
IN
= V
CC
,
V
OUT
= 2.4V
V
CC
= Min, V
IN
= 0,
I
OUT
= 30mA
7
40
Ω
Ω
Notes:
1.
2.
Typical values are specified at V
CC
= 5.0V and T
A
= 25
o
C.
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
I
CCQ
∆I
CC
Q
CCD
Parameter
Quiescent Power Supply Current
Power Supply Current per Input High
(2)
(Control Input)
Dynamic Power Supply Current
(3)
Test Conditions
V
CC
= Max,
V
CC
= Max, V
IN
= 3.4V, f = 0
V
CC
= Max, Switch pins open,
(1)
Max
1
1.5
0.25
Units
µA
mA
mA/MHz
/OE = V
CC
or GND, f = 0
Control Inputs toggling at 50% duty cycle
Notes:
1.
2.
3.
For conditions shown as Min or Max, use the appropriate values per
Recommended Operating Conditions.
Per TTL-driven control input. All other control inputs at GND. Switch I/O pins do not contribute to
∆ICC.
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.
2001-04-12
Vaishali Semiconductor
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www.vaishali.com
747 Camden Avenue, Suite C Campbell CA 95008
MDSS-0007-02
Ph. 408.377.6060
Fax 408.377.6063
VS3245/VS32245
Figure 3. VOLTAGE TRANSLATION
5
4
Vout
(V)
3
2
VCC = 4.3V
Figure 4. VOH CHARACTERISTICS
4.5
TA = 85°C
TA = 25°C
TA = - 40°C
4.0
3.5
VOH
Output Voltage
(V)
3.0
1
0
0
1
2
3
Vin (V)
4
5
2.5
2.0
4.5
5.2
5.0
VCC – Supply Voltage (V)
4.75
5.5
Figure 5. Voltage Translation Application
V
CC
= 5V
1N4148
or equivalent
10K
V
CC
5V
DEVICE
I/O
VS3245
VS32245
/OE
I/O
3.3V
DEVICE
2001-04-12
Vaishali Semiconductor
Page 4
www.vaishali.com
747 Camden Avenue, Suite C Campbell CA 95008
MDSS-0007-02
Ph. 408.377.6060
Fax 408.377.6063
VS3245/VS32245
Table 8. Switching Characteristics Over Operating Range
T
A
= -40 C to +85 C, V
CC
= 5.0V + 10%
C
LOAD
= 50pF, R
LOAD
= 500Ω unless otherwise stated.
o
o
Symbol
t
PLH
, t
PHL
t
PZH
, t
PZL
t
PLZ
, t
PHZ
Description
(1)
VS3245
Min
Max
(3)
VS32245
(3)
Min
Max
1.25
0.5
0.5
6.6
4.5
Units
ns
ns
ns
Data Propagation Delay
(2,3)
through the switch
Switch Turn-on Delay, /OE to A
n
, B
n
Switch Turn-off Delay /OE to A
n
, B
n
0.5
0.5
0.25
5.6
4.5
Notes:
1.
2.
See test circuits and waveforms.
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
VS3245 and 1.25 ns for VS32245. Since this time-constant is much smaller than rise/fall times of typical driving signals, it adds
very little propagation delay to the system.
This parameter is guaranteed, but not production tested.
3.
Figure 6. AC Test Circuit and Switching Waveforms
AC Test Circuit
Load Switch Position
TEST
t
PLH
, t
PHL
S
1
7V
500
Ω
R
L
450Ω
t
PLZ
, t
PZL
t
PHZ
, t
PZH
V
IN
DUT
V
OUT
Open
Closed
Open
S1
Pulse
Generator
50
Ω
Input Conditions
Input voltage = 0 V to 3.0 V
t
r
= t
f
= 2.5ns (10% to 90%)
C
L
50
Ω=
Coax to
Oscilloscope
2001-04-12
Vaishali Semiconductor
Page 5
www.vaishali.com
747 Camden Avenue, Suite C Campbell CA 95008
MDSS-0007-02
Ph. 408.377.6060
Fax 408.377.6063
