2001-04-12 Page
1
MDSS-0013-01
www.vaishali.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 VS32X245 and VS32X2245 are high-speed TTL-compatible 16-bit bus switches in a flow-through pinout.
Each device contains two banks of 8-bit switches with a common active-LOW enable (/OEx) for each bank.
The low ON resistance of the VS32X245 allows inputs to be connected to outputs, without adding
propagation delay and without generating additional signal noise. The VS32X2245 has 25
resistors in series
with the switches to reduce ground-bounce noise from the driving source and signal reflection.
The VS32X245 and VS32X2245 bus switches are function and pinout compatible with QS32X245 and
QS32X2245 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 these switches ideal interface elements for hot-
swap applications.
Figure 1. Functional Block Diagram Figure 2. Pin Configuration
VS32X245 / VS32X2245
High Speed CMOS VSwitch
16-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
(VS32X245) and 25
(VS32X2245)
=
Pin-compatible with QS32X245 and
QS32X2245 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 40 pin QSOP
package
B2
B4 B5
/OE1
B7
B0 B1
A0
B3
B6
A1 A2 A3 A4 A5 A6 A7
B10
B12 B13
/OE2
B15
B8 B9
A8
B11
B14
A9 A10 A11 A12 A13 A14 A15
QSOP
(All Pins Top View)
A0
A2
A4
A6
2
4
8
6
10
13
15
17
19
A8
GND
1
3
5
7
9
NC
A1
A3
A5
A7
11
12
14
16
18
20
GND
NC
A9
A11
A13
A10
A12
A14
A15
21
22
23
25
24
40
29
28
27
26
36
34
33
32
31
30
39
38
37
35
B15
B11
B13
B10
B12
B14
V
CC
B8
B7
/OE2
B9
B6
B2
B4
B1
B3
B5
/OE1
V
CC
B0
VS32X245/VS32X2245
2001-04-12 Page
2
MDSS-0013-01
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
A
0
A
15
I/O
Bus A Data Input or Output
/OE1, /OE2 I
Output enable
B
0
B
15
I/O
Bus B Data Output or Input
Table 2. Function Table
/OE1
/OE2
A0 - A7
A8 A15
Function
H
H
Hi - Z
Hi - Z
Disconnect
L
H
B0 B7
Hi - Z
Connect
H
L
Hi - Z
B8 B15
Connect
L
L
B0 B7
B8 B15
Connect
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.......................................0.92 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 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.
VS32X245/VS32X2245
2001-04-12 Page
3
MDSS-0013-01
www. vaishali.com
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
IN
= 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
,
/OE = V
CC
1
A
VS32X245 50
mA
I
ODL
Switch I/O Drive
Current (Logic LOW)
V
CC
= Min, V
IN
= 0,
V
OUT
= 0.4V
VS32X2245
mA
VS32X245 -50
mA
I
ODH
Switch I/O Drive
Current (Logic HIGH)
V
CC
= Min, V
IN
= V
CC
,
V
OUT
= 2.4V
VS32X2245
mA
VS32X245
5
7
R
ON
Switch
ON
Resistance
(2)
V
CC
= Min, V
IN
= 0,
I
OUT
= 30mA
VS32X2245 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, /OE = V
CC
or GND, f = 0
6
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.
VS32X245/VS32X2245
2001-04-12 Page
4
MDSS-0013-01
www. vaishali.com
Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
1N4148
or equivalent
VOH
Output Voltage
(V)
3
4
5
Vout
(V)
0
1
2
Vin (V)
4
5
3
2
1
0
VCC = 4.3V
Figure 3. VOLTAGE TRANSLATION
Figure 5. Voltage Translation Application
V
CC
10K
V
CC
= 5V
/OE
X
I/O
VS32X245
VS32X2245
3.3V
DEVICE
5V
DEVICE
I/O
Figure 4. VOH CHARACTERISTICS
VCC Supply Voltage (V)
2.0
2.5
5.5
5.0
4.5
3.5
3.0
4.0
4.5
4.75
5.2
TA = 85
C
TA = 25
C
TA = - 40
C
VS32X245/VS32X2245
2001-04-12 Page
5
MDSS-0013-01
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
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, /OE
X
to A
n
, B
n
0.5
5.6
0.5
6.6
ns
t
PLZ
, t
PHZ
Switch Turn-off Delay /OE
X
to A
n
, B
n
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
VS32X245 and 1.25 ns for VS32X2245. 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 6. 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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