ISL84715, ISL84716
7
FN6087.4
August 18, 2015
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Logic-Level Thresholds
This switch family is 1.8V CMOS compatible (0.5V and 1.4V)
over a supply range of 2V to 3.6V (see Figure 13). At 3.6V the
V
IH
level is about 1.1V. This is still below the 1.8V CMOS
guaranteed high output minimum level of 1.4V, but noise
margin is reduced.
The digital input stages draw supply current whenever the
digital input voltage is not at one of the supply rails. Driving the
digital input signals from GND to V+ with a fast transition time
minimizes power dissipation.
High-Frequency Performance
In 50Ω systems, signal response is reasonably flat even past
100MHz (See Figure 14). The frequency response is very
consistent over a wide V+ range, and for varying analog signal
levels.
An OFF switch acts like a capacitor and passes higher
frequencies with less attenuation, resulting in signal
feedthrough from a switch’s input to its output. Off Isolation is
the resistance to this feedthrough. Figure 15 details the high
Off Isolation rejection provided by this family. At 1MHz, Off
Isolation is about 45dB in 50Ω systems, decreasing
approximately 20dB per decade as frequency increases.
Higher load impedances decrease Off Isolation and Crosstalk
rejection due to the voltage divider action of the switch OFF
impedance and the load impedance.
Leakage Considerations
Reverse ESD protection diodes are internally connected between
each analog-signal pin and both V+ and GND. One of these diodes
conducts if any analog signal exceeds V+ or GND.
Virtually all the analog leakage current comes from the ESD
diodes to V+ or GND. Although the ESD diodes on a given
signal pin are identical and therefore fairly well balanced, they
are reverse biased differently. Each is biased by either V+ or
GND and the analog signal. This means their leakages will vary
as the signal varies. The difference in the two diode leakages
to the V+ and GND pins constitutes the analog-signal-path
leakage current. All analog leakage current flows between
each pin and one of the supply terminals, not to the other
switch terminal. This is why both sides of a given switch can
show leakage currents of the same or opposite polarity. There
is no connection between the analog signal paths and V+ or
GND.
Typical Performance Curves T
A
= +25°C, unless otherwise specified
FIGURE 7. ON RESISTANCE vs SUPPLY VOLTAGE vs SWITCH
VOLTAGE
FIGURE 8. ON RESISTANCE vs SWITCH VOLTAGE
R
ON
(Ω)
V
COM
(V)
01234
0.2
0.3
0.4
0.5
0.6
0.7
V+ = 2.7V
V+ = 1.8V
V+ = 1.5V
V+ = 3.6V
V+ = 3V
I
COM
= 100mA
R
ON
(Ω)
V
COM
(V)
0 0.5 1.0 1.5 2.0 2.5 3.0
V+ = 2.7V
I
COM
= 100mA
0.15
0.2
0.25
0.3
0.35
0.4
+25°C
+85°C
-40°C
