ISL54050_14 Datasheet, PDF (9/12 Pages) Intersil Corporation – Ultra Low ON-Resistance, +1.65V to +4.5V,Single Supply, Dual SPDT Analog Switch

ISL54050
Frequency Performance
In 50Ω systems, the ISL54050 has a -3dB bandwidth of
25MHz (see Figure 22). 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
feed-through from a switch’s input to its output. OFF-
isolation is the resistance to this feed-through, while
crosstalk indicates the amount of feed-through from one
switch to another. Figure 23 details the high OFF-isolation
and crosstalk rejection provided by this part. At 100kHz,
OFF-isolation is about 62dB 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.
0.30
0.35
I_COM = 100mA
0.34
0.29
0.33
0.28
0.32
V+ = 2.7V
I_COM = 100mA
0.27
V+ = 3.9V
0.26
V+ = 4.3V
0.25
V+ = 4.5V
0
1
2
3
4
5
V_COM (V)
FIGURE 10. ON-RESISTANCE vs SUPPLY VOLTAGE vs
SWITCH VOLTAGE
0.31
V+ = 3V
0.30
0.29
V+ = 3.3V
0.28
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
V_COM (V)
FIGURE 11. ON-RESISTANCE vs SUPPLY VOLTAGE vs
SWITCH VOLTAGE
0.70
I_COM = 100mA
0.65
0.60
V+ = 1.65V
0.55
0.50
V+ = 1.8V
0.45
V+ = 2V
0.40
0.35
0.30
0
0.5
1.0
1.5
2.0
V_COM (V)
FIGURE 12. ON-RESISTANCE vs SUPPLY VOLTAGE vs
SWITCH VOLTAGE
0.35
+85°C
0.30
V+ = 4.3V
I_COM = 100mA
+25°C
0.25
-40°C
0.20
0
1
2
3
4
5
V_COM (V)
FIGURE 13. ON-RESISTANCE vs SWITCH VOLTAGE
9
FN6356.4
November 22, 2008