8

FN6579.2

March 11, 2011

Detailed Description

The ISL54059 is a bi-directional, dual single pole-double

throw (SPDT) analog switch that offers precise switching

from a single 1.8V to 6.5V supply with low ON-resistance

(0.83

The device is especially well suited for portable battery

powered equipment due to its low operating supply voltage

(1.8V), low power consumption (8nA), and a tiny 1.8x1.4mm

µTQFN package or a 3x3mm TDFN package. The low

loss and signal distortion for applications that require signal

switching with minimal interference by the switch.

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. The ISL54059

contains ESD protection diodes on each pin of the IC

(see Figure 8). These diodes connect to either a +Ring or

-Ring for ESD protection. To prevent forward biasing the

ESD diodes to the +Ring, V+ must be applied before any

input signals, and the input signal voltages must remain

between recommended operating range.

If these conditions cannot be guaranteed, then precautions

must be implemented to prohibit the current and voltage at

the logic pin and signal pins from exceeding the maximum

ratings of the switch. The following two methods can be used

to provided additional protection to limit the current in the

event that the voltage at a logic pin or switch terminal goes

above the V+ rail.

Logic inputs can be protected by adding a 1k

Ω resistor in

series with the logic input (see Figure 8). The resistor limits

FIGURE 4. OFF-ISOLATION TEST CIRCUIT

FIGURE 6. CROSSTALK TEST CIRCUIT

FIGURE 7. CAPACITANCE TEST CIRCUIT

ANALYZER

SIGNAL

GENERATOR

V+

C

0V OR V+

NO OR NC

COM

IN

GND

Signal direction through switch is reversed, worst case values

are recorded. Repeat test for all switches.

*50

Ω SOURCE

V+

C

0V OR V+

NO OR NC

COM

IN

GND

100mA

Repeat test for all switches.

0V OR V+

ANALYZER

V+

C

NO1 OR NC1

SIGNAL

GENERATOR

GND

COM1

50

Ω

NC

COM2

NC2 OR NO2

Signal direction through switch is reversed, worst case values

are recorded. Repeat test for all switches.

*50

Ω SOURCE

V+

C

GND

NO OR NC

COM

IN

IMPEDANCE

ANALYZER

0V OR V+

COM is connected to NO or NC

during ON capacitance measurement.

ISL54059