ISL43112 Datasheet, PDF (7/11 Pages) Intersil Corporation – Low-Voltage, Dual Supply, SPST, High Performance Analog Switches

ISL43112, ISL43113
compatible, TTL compatible versions of these switches, see
the ISL43110/11 data sheet.
Logic-Level Thresholds
Due to the lack of a GND pin, the switching point of the
digital input is referenced predominantly to V+. The digital
input is CMOS compatible at ±5V supplies, and is TTL
compatible for ±3.3V supplies. For other supply
combinations refer to Figures 13 and 14.
The switching point has a very low temperature sensitivity,
and changes by only 100mV from 85^oC to -40^oC, regardless
of supply voltage.
High-Frequency Performance
In 50Ω systems, signal response is reasonably flat to
30MHz, with a -3dB bandwidth of nearly 400MHz (see
Figure 15). Figure 15 also illustrates that 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 16 details the
high OFF Isolation provided by this family. At 10MHz, OFF
Isolation is about 50dB in 50Ω systems, decreasing
approximately 20dB per decade as frequency increases.
Higher load impedances decrease OFF Isolation 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 V-. One of
these diodes conducts if any analog signal exceeds V+ or V-.
Virtually all the analog leakage current comes from the ESD
diodes to V+ or V-. 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 V- 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 V- 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 V-.
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