2001-04-12 Page
1
MDSS-0011-01
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
=
Video, audio switching
=
Clock gating
=
Logic replacement
General Description
The VS3125 contains a set of four high-speed, low-resistance bus switches. Each bus switch is individually
controlled by TTL-compatible, active-low control input (/xOE). The low ON resistance of VS3125 allows
inputs to be connected to outputs without adding propagation delay and without generating additional signal
noise.
The VS3125 is function and pinout compatible with QS3125. It enables 5V to 3.3V level translation when
used with an external diode in the power supply line. In addition, the high off-isolation between switch
terminals in the `disable' mode, and the near-zero propagation delay in the `on' state make the VS3V125 an
ideal interface element for hot-swapping 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
=
Pin-compatible with QS3125 & PI5C3125
switches
=
Zero added ground bounce or signal noise
=
TTL-compatible control signals
=
Near-zero propagation delay
=
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
VS3125
Quad Bus Switch with
Individual Active Low Enables
QSOP
NC
/1OE
1A
1Y
/2OE
2A
2Y
/4OE
4A
4Y
/3OE
3A
3Y
GND
V
CC
NC
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
All Pins, Top View
NC= No Connect
1A
2A
3A
4A
1Y
2Y 3Y
4Y
/1OE
/2OE
/3OE
/4OE
VS3125
2001-04-12 Page
2
MDSS-0011-01
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
1A 4A
I/O
Data Input or Output
1Y 4Y
I/O
Data Input or Output
/1OE - /4OE
I
Bus Switch Enable
Table 2. Function Table
/xOE Path Function
L
xA <-> xY
Enable switch
H
High Impedance
Disable switch
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.............................120mA
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.
Functional operation under absolute maximum rated conditions is not implied.
Table 4. Capacitance
T
A
= 25
o
C, f = 1MHz, 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.
Table 5. Recommended Operating Conditions
Symbol Parameter
Min Typ Max
Units
V
CC
Power supply voltage
4.5
5.5
V
V
IL
Low level input voltage
(Control inputs)
-0.5
0.8
V
V
IH
High level input voltage
(Control inputs)
2.0
5.5
V
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
VS3125
2001-04-12 Page
3
MDSS-0011-01
www.vaishali.com
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
(1)
Max Units
Control Inputs
-1.5
V
IK
Clamp
Voltage
Switch I/O
V
CC
= Min., I
IK
= -18mA
-1.5
V
V
OH
Logic High Voltage
V
CC
= 4.3V,V
IN
= 5V
Switch I/O
V
IN
= V
CC
= 5V, I
OUT
= -5
A
V
CC
= 4.3V,V
IN
= 5V,
I
OUT
= -100
A
3.7
3.0
3.9
3.3
4.1
3.6
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
,
/xOE= V
CC
1
A
I
ODL
Switch I/O Drive
Current (Logic LOW)
V
CC
= Min, V
IN
= 0, V
OUT
= 0.4V
50
mA
I
ODH
Switch I/O Drive
Current (Logic HIGH)
V
CC
= Min, V
IN
= V
CC
, V
OUT
= 2.4V
-50
mA
R
ON
Switch
ON
Resistance
(2)
V
CC
= 3.0V, V
IN
= 0, I
OUT
= 15mA
5
(2)
7
Notes:
1. Typical value is specified at V
CC
= 5V 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 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.,/xOE = V
CC
or GND, f = 0
1
A
I
CC
Power Supply Current per Input
High
(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 specified under Recommended Operating
Conditions.
2. Per control input. All other control inputs at GND. Switch I/O pins do not contribute to
I
CC
.
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.
VS3125
2001-04-12 Page
4
MDSS-0011-01
www.vaishali.com
Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Figure 4. VOH CHARACTERISTICS
Figure 3. VOLTAGE TRANSLATION
Figure 5. Voltage Translation. Application
V
CC
= 5V
V
CC
10K
/E
I/O
VS3125
3.3V
DEVICE
5V
DEVICE
I/O
1N4148
or equivalent
3
4
5
0
1
2
4 5
3
2
1
0
VCC = 4.3V
VOH
Output 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
VCC Supply Voltage (V)
Vin (V)
Vout
(V)
VS3125
2001-04-12 Page
5
MDSS-0011-01
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
= 5V + 10%
C
LOAD
= 50pF, R
LOAD
= 500
unless otherwise stated.
Symbol Description
(1)
Min
(3)
Max Units
t
PLH
, t
PHL
Data Propagation Delay
(2,3)
through the switch
-
0.25
ns
t
PZH
, t
PZL
Switch Turn-on Delay, /xOE to xA or xY
1.5
6.5
ns
t
PLZ
, t
PHZ
Switch Turn-off Delay
(3)
,
/xOE to xA or xY
1.5
5.5
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
of the order of 0.25ns for VS3125. 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
Pulse
Generator
DUT
V
IN
V
OUT
C
L
500
R
L
S
1
7 V
50
=
Coax to
Oscilloscope
50
450
TEST S1
t
PLH
, t
PHL
Open
t
PLZ
, t
PZL
Closed
t
PHZ
, t
PZH
Open
Input Conditions
1. Input voltage = 0 V to 3.0 V
2. t
r
= t
f
= 2.5ns (10% to 90%)
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