5

Detailed Description

The ISL84516 and ISL84517 analog switches offer precise

switching capability from

±1.5V to ±6V supplies with low on-

resistance (13

portable battery powered equipment thanks to the low

operating supply voltage (

±1.5V), low power consumption

(350

µW), low leakage currents (2nA max), and the tiny

SOT-23 packaging. High frequency applications also benefit

from the wide bandwidth, and the very high off isolation.

Supply Sequencing And Overvoltage Protection

With any CMOS device, proper power supply sequencing is

required to protect the device from excessive input currents

which might permanently damage the IC. All I/O pins contain

ESD protection diodes from the pin to V+ and to V- (see

Figure 6). To prevent forward biasing these diodes, V+ and

V- must be applied before any input signals, and input signal

voltages must remain between V+ and V-. If these conditions

cannot be guaranteed, then one of the following two

protection methods should be employed.

Logic inputs can easily be protected by adding a 1k

Ω

resistor in series with the input (see Figure 6). The resistor

limits the input current below the threshold that produces

permanent damage, and the sub-microamp input current

produces an insignificant voltage drop during normal

operation.

Adding a series resistor to the switch input defeats the

diodes can be added in series with the supply pins to provide

overvoltage protection for all pins (see Figure 6). These

additional diodes limit the analog signal from 1V below V+ to

1V above V-. The low leakage current performance is

ANALYZER

SIGNAL

GENERATOR

V+

C

V- or V+

NO or NC

COM

IN

V-

C

FIGURE 3. OFF ISOLATION TEST CIRCUIT

V+

C

NO or NC

COM

IN

1mA

V-

C

V+

NO or NC

COM

IN

IMPEDANCE

ANALYZER

V- or V+

V-

FIGURE 5. CAPACITANCE TEST CIRCUIT

ISL84516, ISL84517