ISL54500 Datasheet, PDF (9/13 Pages) Intersil Corporation – +1.8V to +5.5V, 5OHM, Single SPDT Analog Switch

ISL54500
very consistent over a wide V+ range, and for varying
analog signal levels.
One of these diodes conducts if any analog signal
exceeds V+ or GND.
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, while
crosstalk indicates the amount of feedthrough from
one switch to another. Figure 18 details the high
off-isolation provided by this family. At 1MHz,
of-isolation is about 75dB 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
ESD protection diodes are internally connected
between each analog-signal pin and both V+ and 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
8
6
I_COM = 100mA
7
V+ = 2.7V
5
6
V+ = 4.5V
I_COM = 100mA
5
V+ = 3V
4
V+ = 4.5V
3
V+ = 5V
2
1
4
+85°C
+25°C
3
-40°C
2
0
0
1
2
3
4
5
V_COM (V)
FIGURE 10. ON-RESISTANCE vs SUPPLY VOLTAGE vs
SWITCH VOLTAGE
1
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
V_COM (V)
FIGURE 11. ON-RESISTANCE vs SWITCH VOLTAGE
8
7
+85°C
6
+25°C
5
-40°C
4
3
V+ = 2.7V
I_COM = 100mA
2
0
0.5
1.0
1.5
2.0
2.5
V_COM (V)
FIGURE 12. ON-RESISTANCE vs SWITCH VOLTAGE
14
13
12
11
10
+85°C
9
8
+25°C
7
6
-40°C
5
4
V+ = 1.8V
I_COM = 10mA
3
2
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
V_COM (V)
FIGURE 13. ON-RESISTANCE vs SWITCH VOLTAGE
9
FN6549.2
November 9, 2009