VAISH VS3257

VS3257 / VS32257
Quad 2:1 Mux/Demux VSwitch
Applications
•=
5V to 3.3V translation in mixed-supply
environment
•=
Memory bank, video, & audio
swtiching
•=
Hot-swap interface
•=
Power conservation
•=
Logic replacement
General Description
The VS3257 is a high-speed TTL–compatible Quad 2:1 multiplexer/demultiplexer. The VS3257 contains four
mux/demux channels, with a common path control (S) and active low enable (/E). The low ON resistance of
the VS3257 allows inputs to be connected to outputs, without adding propagation delay and without
generating additional signal noise. The VS32257 has 25Ω resistors in series with the switches to reduce
ground-bounce noise and signal reflection.
The VS3257 and VS32257 mux/demux switches are function and pinout compatible with QS3257 and
CBT3257 switches. They enable 5V to 3.3V translation when used with an external diode in the power supply
line. In addition, the high off-isolation in the ‘disable’ mode makes VS3257 and VS32257 ideal interface
elements for hot-swap applications.
Features
•=
Enhanced N-FET with no DC path to VCC
or GND in normal operating signal voltage
range.
•=
Low impedance bidirectional data flow:
5Ω (VS3257) and 25Ω (VS32257)
•=
Pin-compatible with QS3257 and CBT3257
switches.
•=
Near zero propagation delay
•=
Zero added ground bounce or signal noise
•=
Break-before-make feature
•=
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)
S
QSOP
/E
YA
YB
YC
YD
2001-04-12
I0A
I1A
I0B
I1B
I0C
I1C
I0D
I1D
S
1
16
I0A
2
15
I1A
3
14
VCC
/E
I0D
YA
I0B
4
13
I1D
12
11
YD
I1B
5
6
YB
7
10
I1C
GND
8
9
YC
I0C
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VS3257/VS32257
Table 1. Pin Description
Name
I/O
Description
I0X, I1X
I/O
Data Input or Output
S
I
Select Input
/E
I
Enable Input
YA - YD
I/O
Data Output or Input
Table 2. Function Table
Inputs
Path
Function
/E
S
H
X
Hi Impedance
Disable all switches
L
L
IOX <-> YX
Select 0
L
H
I1X <-> YX
Select 1
Table 3. Absolute Maximum Ratings
Supply Voltage to Ground………………………….…..-0.5V to +7.0V
DC Switch Voltage VS……………………….………….-0.5V to +7.0V
DC Input Voltage VIN………………………………… ...-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
o
o
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.
Table 4. Capacitance
o
TA = 25 C, f = 1 MHz, VIN = 0V, VOUT = 0V
QSOP
Pins
Operation
Control Inputs
Typ
Max
Unit
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.
2001-04-12
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VS3257/VS32257
Table 5. Recommended Operating Conditions
Symbol
Parameter
Conditions
Min
Typ
Max
Units
VCC
Power supply voltage
4.5
5.5
V
VIL
Low level input voltage
-0.5
0.8
V
VIH
High level input voltage
2.0
5.5
V
TA
Operating free-air temperature
-40
85
o
C
Note:
1. All unused control inputs of the device must be held at Vcc or GND, to ensure proper device operation
Table 6. Electrical Characteristics Over Recommended Operating Free-air Temperature Range
Symbol
VIK
Parameter
Clamp Voltage
Test Conditions
Control Inputs
Min
Typ
(1)
VCC = Min, IIK = -18 mA
Switch I/O
VOH
Logic High Voltage
Max
Units
-1.5
V
-1.5
Switch I/O
VIN = VCC = 5V, IOUT = -5µA
3.7
3.9
4.1
VCC = 4.3V, VN = 5V,
3.0
3.3
3.6
V
IOUT = -5µA
II
Input Leakage
Current
Control Inputs
VCC = Max, VI = VCC or GND
1
µA
|OFF|
Power OFF Leakage
Current
Control Inputs
VCC = 0,
1
µA
Switch I/O
VI or VO = VCC or GND
|IOZ|
OFF State Leakage
Current
Switch I/O
VCC = Max, VI/O = VCC,
/E = VCC
1
µA
IODL
Switch I/O Drive
Current (Logic LOW)
VCC = Min, VIN = 0,
VS3257
VOUT = 0.4V
VS32257
VCC = Min, VIN = VCC,
VS3257
VOUT = 2.4V
VS32257
VCC = Min, VIN = 0,
VS3257
IOUT = 30mA
VS32257
IODH
RON
Switch I/O Drive
Current (Logic HIGH)
Switch ON
(2)
Resistance
50
mA
mA
-50
mA
mA
20
5
7
Ω
28
40
Ω
Notes:
1.
2.
Typical values are specified at VCC = 5.0V and TA = 25oC.
RON 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)
Units
1
µA
ICCQ
Quiescent Power Supply Current
VCC = Max,
∆ICC
Power Supply Current per Input High
(2)
(Control Inputs)
VCC = Max, VIN = 3.4V, f = 0
1.5
mA
QCCD
Dynamic Power Supply Current
VCC = Max, Switch pins open,
0.25
mA/MHz
(3)
S, /E = VCC or GND, f = 0
Max
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
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Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
VS3257/VS32257
Figure 4. VOH CHARACTERISTICS
Figure 3. VOLTAGE TRANSLATION
4.5
5
TA = 85°C
TA = 25°C
TA = - 40°C
4.0
4
Vout
(V)
VCC = 4.3V
2
3.5
VOH
Output Voltage
(V)
3.0
1
2.5
3
2.0
0
1
0
2
3
4
4.5
5
4.75
5.0
5.25
5.5
VCC – Supply Voltage (V)
Vin (V)
Figure 5. Voltage Translation. Application
VCC = 5V
1N4148
or equivalent
10K
VCC
5V
DEVICE
I/O
I/O
3.3V
DEVICE
VS3257
VS32257
/E
2001-04-12
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Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
VS3257/VS32257
Table 8. Switching Characteristics Over Operating Range
o
o
TA = -40 C to +85 C, VCC = 5.0V + 10%
CLOAD = 50pF, RLOAD = 500Ω unless otherwise stated.
Symbol
Description
(2,3)
(1)
Min
VS3257
Max
VS32257
(3)
Min
Max
0.25
1.25
ns
Units
tPLH, tPHL
Data Propagation Delay
tPZH, tPZL
Switch Turn-on Delay, S to YX, I0X, or I1X
0.5
5.2
0.5
6.2
ns
tPZH, tPZL
Switch Turn-on Delay, /E to YX, I0X, or I1X
0.5
4.8
0.5
5.8
ns
0.5
5.0
0.5
5.0
ns
tPLZ, tPHZ
Switch Turn-off Delay
through the switch
(3)
(3)
, S or /E to YX, I0X, or I1X
Notes:
1.
2.
3.
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
VS3257 and 1.25 ns for VS32257. 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.
Figure 6. AC Test Circuit and Switching Waveforms
Load Switch Position
AC Test Circuit
TEST
S1
7V
VIN
Pulse
Generator
VOUT
RL
450Ω
2001-04-12
CL
Open
tPLZ, tPZL
Closed
tPHZ, tPZH
Open
500Ω
DUT
50Ω
S1
tPLH, tPHL
50Ω=Coax to
Oscilloscope
Input Conditions
Input voltage = 0 V to 3.0 V
tr = tf = 2.5ns (10% to 90%)
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Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
VS3257/VS32257
Switching Waveforms
3.0 V
Input
1.5 V
0V
tPLH
tPHL
VOH
Switch Output
1.5 V
VOL
Propagation Delay
3.0 V
1.5 V
Control Input
0V
tPZH
tPHZ
VOH
0.3 V
Switch Output
(Switch Input = 3.0 V)
1.5 V
0V
tPLZ
Switch Output
(Switch Input = 0 V)
tPZL
0.3 V
Switch ON
Switch OFF
3.5 V
1.5 V
VOL
Switch ON
Enable and Disable Times
Ordering Information
Part Number
VS3257Q
VS32257Q
2001-04-12
No. of Pins
16
16
Package
QSOP
QSOP
Temperature
-40°C to +85°C
-40°C to +85°C
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MDSS-0009-01
www.vaishali.com
Vaishali Semiconductor 747 Camden Avenue, Suite C Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063