ISL54050_0706 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
120MHz (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
FN6356.2
June 11, 2007