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 VCC 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 VCC /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
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VS3245/VS32245 Table 1. Pin Description Name
A0 - A7 /OE B0 – B7 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 An Bn Disable all switches An = Bn
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
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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
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VS3245/VS32245 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
Table 6. Electrical Characteristics Over Recommended Operating Free-air Temperature Range Symbol
VIK VOH
Parameter
Clamp Voltage Logic High Voltage Control Input Switch I/O Switch I/O
Test Conditions
VCC = Min, IIK = -18 mA VIN = VCC = 5V, IOUT = -5µA VCC = 4.3V, VN = 5V, IOUT = -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
II |OFF| |IOZ| IODL IODH RON
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
VCC = Max, VI = VCC or GND VCC = 0, VI or VO = VCC or GND VCC = Max, VI/O = VCC, /OE = VCC VS3245 VS32245 VS3245 VS32245 VS3245 VS32245 20 5 28 -50 50
µA µA µA mA mA mA mA
VCC = Min, VIN = 0, VOUT = 0.4V VCC = Min, VIN = VCC, VOUT = 2.4V VCC = Min, VIN = 0, IOUT = 30mA
7 40
Ω 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
ICCQ ∆ICC QCCD
Parameter
Quiescent Power Supply Current Power Supply Current per Input High (2) (Control Input) 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
/OE = 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.
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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 4.75 5.0 VCC – Supply Voltage (V) 5.5
Figure 5. Voltage Translation Application
VCC = 5V 1N4148 or equivalent
10K
VCC
5V DEVICE
I/O VS3245 VS32245 /OE
I/O
3.3V DEVICE
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VS3245/VS32245
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 tPLZ, tPHZ
Description
Data Propagation Delay
(2,3)
(1)
Min
0.5 0.5
(3)
VS3245 Max
0.25 5.6 4.5
VS32245 (3) Min Max
1.25 0.5 0.5 6.6 4.5
Units
ns ns ns
through the switch
Switch Turn-on Delay, /OE to An, Bn Switch Turn-off Delay /OE to An, Bn
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
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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VS3245/VS32245 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 VS3245Q VS3245QX VS32245Q VS32245QX Marking VS3245Q VS3245Q VS32245Q VS32245Q Shipping/Packaging Tubes Tape & Reel Tubes Tape & Reel No. of Pins 20 20 20 20 Package QSOP QSOP QSOP QSOP Temperature -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C
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