VS3257 / VS32257 Quad 2:1 Mux/Demux VSwitch
Applications
•= •= •= 5V to 3.3V translation in mixed-supply environment Hot-swap interface Logic replacement •= •= Memory bank, video, & audio swtiching Power conservation
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 /E YA YB YC YD I0A I1A I0B I1B I0C I1C I0D I1D
S I0A I1A YA I0B I1B YB GND 1 2 3 4 5 6 7 8
QSOP
16 15 14 13 12 11 10 9 VCC /E I0D I1D YD I0C I1C YC
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VS3257/VS32257 Table 1. Pin Description Name
I0X, I1X S /E YA - YD I I I/O
I/O
I/O
Description
Data Input or Output Select Input Enable Input Data Output or Input
Table 2. Function Table Inputs
/E H L L S X L H Hi Impedance IOX YX I1X YX Disable all switches Select 0 Select 1
Path
Function
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 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.
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Table 4. Capacitance
TA = 25 C, f = 1 MHz, VIN = 0V, VOUT = 0V
o
QSOP Pins
Control Inputs VSwitch Channels (Switch OFF) Demux Mux
Operation
Typ
4 5 7
Max
5 7 8
Unit
pF pF 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.
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VS3257/VS32257 Table 5. Recommended Operating Conditions Symbol
VCC VIL VIH TA
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
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 Control Inputs Switch I/O VOH Logic High Voltage Switch I/O VIN = VCC = 5V, IOUT = -5µA VCC = 4.3V, VN = 5V, IOUT = -5µA II |OFF| 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 Inputs Control Inputs Switch I/O Switch I/O VCC = Min, VIN = 0, VOUT = 0.4V VCC = Min, VIN = VCC, VOUT = 2.4V VCC = Min, VIN = 0, IOUT = 30mA VCC = Max, VI = VCC or GND VCC = 0, VI or VO = VCC or GND VCC = Max, VI/O = VCC, /E = VCC VS3257 VS32257 VS3257 VS32257 VS3257 VS32257 20 5 28 7 40 -50 50 1 µA mA mA mA mA Ω Ω 1 1 µA µA 3.7 3.0 3.9 3.3 Test Conditions VCC = Min, IIK = -18 mA Min Typ
(1)
Max -1.5 -1.5 4.1 3.6
Units V
V
|IOZ| IODL
IODH
RON
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
ICCQ ∆ICC QCCD
Parameter
Quiescent Power Supply Current Power Supply Current per Input High (2) (Control Inputs) Dynamic Power Supply Current
(3)
Test Conditions
VCC = Max, VCC = Max, VIN = 3.4V, f = 0 VCC = Max, Switch pins open,
(1)
Max
1 1.5 0.25
Units
µA mA mA/MHz
S, /E = VCC 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. Page 3 www.vaishali.com 747 Camden Avenue, Suite C Campbell CA 95008 MDSS-0009-01 Ph. 408.377.6060 Fax 408.377.6063
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VS3257/VS32257
Figure 3. VOLTAGE TRANSLATION
Figure 4. VOH CHARACTERISTICS
5 4 Vout (V) 3 2 1 0 0 VCC = 4.3V
4.5 4.0 3.5 VOH Output Voltage (V) 3.0 2.5 2.0 1 2 Vin (V) 3 4 5 4.5 4.75 5.0 5.25 5.5 VCC – Supply Voltage (V) TA = 85°C TA = 25°C TA = - 40°C
Figure 5. Voltage Translation. Application
VCC = 5V 1N4148 or equivalent
10K
VCC
5V DEVICE
I/O VS3257 VS32257 /E
I/O
3.3V DEVICE
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VS3257/VS32257
Table 8. Switching Characteristics Over Operating Range
TA = -40 C to +85 C, VCC = 5.0V + 10% CLOAD = 50pF, RLOAD = 500Ω unless otherwise stated.
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Symbol
tPLH, tPHL tPZH, tPZL tPZH, tPZL tPLZ, tPHZ
Description
Data Propagation Delay
(2,3)
(1)
Min
0.5 0.5 0.5
(3)
VS3257 Max
0.25 5.2 4.8 5.0
VS32257 (3) Min Max
1.25 0.5 0.5 0.5 6.2 5.8 5.0
Units
ns ns ns ns
through the switch
Switch Turn-on Delay, S to YX, I0X, or I1X Switch Turn-on Delay, /E to YX, I0X, or I1X Switch Turn-off Delay
(3)
, S or /E to YX, I0X, or I1X
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 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.
3.
Figure 6. AC Test Circuit and Switching Waveforms
AC Test Circuit
Load Switch Position TEST
tPLH, tPHL S1 7V 500Ω RL 450Ω tPLZ, tPZL tPHZ, tPZH VIN DUT VOUT Open Closed Open
S1
Pulse Generator 50Ω
Input Conditions
Input voltage = 0 V to 3.0 V tr = tf = 2.5ns (10% to 90%)
CL
50Ω=Coax to Oscilloscope
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VS3257/VS32257
Switching Waveforms
3.0 V Input 1.5 V 0V tPLH Switch Output tPHL VOH 1.5 V VOL
Propagation Delay
Control Input
3.0 V 1.5 V 0V tPHZ tPZH VOH 1.5 V 0V tPLZ tPZL 0.3 V Switch ON Switch OFF 3.5 V 1.5 V VOL
0.3 V Switch Output (Switch Input = 3.0 V)
Switch Output (Switch Input = 0 V)
Switch ON
Enable and Disable Times
Ordering Information
Part Number VS3257Q VS32257Q
No. of Pins 16 16
Package QSOP QSOP
Temperature -40°C to +85°C -40°C to +85°C
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