ISL8499_14 Datasheet, PDF (7/14 Pages) Intersil Corporation – Ultra Low ON-Resistance, +1.65V to +4.5V,Single Supply, Quad SPDT (Dual DPDT) Analog Switch

ISL8499
Test Circuits and Waveforms (Continued)
V+
C
SIGNAL
GENERATOR
NO or NC
IN 0V or V+
r_ON = V₁/100mA
V_NX
NO or NC
100mA
V₁
V+
C
0V or V+
IN
ANALYZER
R_L
COM
GND
COM
GND
FIGURE 4. OFF ISOLATION TEST CIRCUIT
FIGURE 5. r_ON TEST CIRCUIT
SIGNAL
GENERATOR
NO or NC
IN₁
0V or V+
V+
C
COM
50Ω
ANALYZER
R_L
COM
NC or NO
GND
N.C.
FIGURE 6. CROSSTALK TEST CIRCUIT
Detailed Description
The ISL8499 is a bidirectional, quad single pole/double
throw (SPDT) analog switch that offers precise switching
capability from a single 1.65V to 4.5V supply with low
on-resistance (0.24Ω) and high speed operation
(t_ON = 15ns, t_OFF = 13ns). The device is especially well
suited for portable battery powered equipment due to its low
operating supply voltage (1.65V), low power consumption
(2.7µW max), low leakage currents (150nA max), and the tiny
TQFN, QFN and TSSOP packages. The ultra low
ON-Resistance and r_ON flatness provide very low insertion
loss and distortion to applications that require signal
reproduction.
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
7
IMPEDANCE
ANALYZER
NO or NC
V+
C
IN 0V or V+
COM
GND
FIGURE 7. CAPACITANCE TEST CIRCUIT
ESD protection diodes from the pin to V+ and to GND (see
Figure 8). To prevent forward biasing these diodes, V+ must
be applied before any input signals, and the input signal
voltages must remain between V+ and GND. 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.
This method is not acceptable for the signal path inputs.
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
FN6111.3
February 5, 2008