ISL43240_04 Datasheet, PDF (8/14 Pages) Intersil Corporation – Low-Voltage, Single and Dual Supply, Quad SPDT, High Performance Analog Switches

ISL43240
Test Circuits and Waveforms (Continued)
V+
C
SIGNAL
GENERATOR
NO or NC
IN ^{0V or 2.4V}
ANALYZER
R_L
COM
GND
C
V-
Repeat test for all switches.
FIGURE 4. OFF ISOLATION TEST CIRCUIT
V+
C
R_ON = V₁/1mA
V_NX
NO or NC
1mA
V₁
V+
C
IN
0.8V or 2.4V
COM
GND
C
V-
Repeat test for all switches.
FIGURE 5. R_ON TEST CIRCUIT
V+
SIGNAL
GENERATOR
NO1 or NC1
COM1
50Ω
NO or NC
IN₁
0V or 2.4V
IN₂ ^{0V or 2.4V}
ANALYZER
R_L
COM2
NO2 or NC2
GND
NO
CONNECTION
C
V-
FIGURE 6. CROSSTALK TEST CIRCUIT
IMPEDANCE
ANALYZER
IN 0V or 2.4V
COM
GND
V-
FIGURE 7. CAPACITANCE TEST CIRCUIT
Detailed Description
The ISL43240 quad analog switches offer precise switching
capability from a bipolar ±2V to ±6V or a single 2V to 12V
supply with low on-resistance (18Ω) and high speed
operation (t_ON = 52ns, t_OFF = 40ns). The devices are
especially well suited for portable battery powered
equipment thanks to the low operating supply voltage (2V),
low power consumption (5µW), low leakage currents (5nA
max). High frequency applications also benefit from the wide
bandwidth, and the very high off isolation and crosstalk
rejection.
Supply Sequencing And Overvoltage Protection
With any CMOS device, proper power supply sequencing is
required to protect the device from excessive input currents
which might permanently damage the IC. All I/O pins contain
ESD protection diodes from the pin to V+ and to V- (see
8
Figure 8). To prevent forward biasing these diodes, V+ and
V- must be applied before any input signals, and input signal
voltages must remain between V+ and V-. If these conditions
cannot be guaranteed, then one of the following two
protection methods should be employed.
Logic inputs can easily be protected by adding a 1kΩ
resistor in series with the input (see Figure 8). The resistor
limits the input current below the threshold that produces
permanent damage, and the sub-microamp input current
produces an insignificant voltage drop during normal
operation.
Adding a series resistor to the switch input defeats the purpose
of using a low R_ON switch, so two small signal diodes can be
added in series with the supply pins to provide overvoltage
protection for all pins (see Figure 8). These additional diodes
limit the analog signal from 1V below V+ to 1V above V-.