ESD Test Conditions

ESD performance depends on several conditions.

Contact Maxim for a reliability report that documents

test setup, methodology, and results.

Human Body Model

Figure 6 shows the Human Body Model, and Figure 7

shows the current waveform it generates when dis-

charged into a low impedance. This model consists of

a 100pF capacitor charged to the ESD voltage of inter-

est, which is then discharged into the test device

through a 1.5k

Ω resistor.

Power-Supply Considerations

The MAX4558/MAX4559/MAX4560 are typical of most

CMOS analog switches. They have three supply pins:

CMOS switches and set the limits of the analog voltage

on every switch. Internal reverse ESD-protection diodes

of these diodes conducts. The only currents drawn

age currents of these ESD diodes.

Although the ESD diodes on a given signal pin are

identical and therefore fairly well balanced, they are

vary as the signal varies. The difference in the two

analog signal-path leakage current. All analog leakage

current flows between each input 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 either the same or opposite polarity.

translators, and set the input logic limits. The logic-level

This drive signal is the only connection between the

logic supplies and logic signals and the analog sup-

GND.

The logic-level thresholds are TTL/CMOS compatible

about 3.1V (above the TTL-guaranteed high-level mini-

mum of 2.4V, but still compatible with CMOS outputs).

High-Frequency Performance

In 50

Ω systems, signal response is reasonably flat up

to 50MHz (see

Typical Operating Characteristics).

Above 20MHz, the on response has several minor

peaks that are highly layout dependent. The problem is

not turning the switch on, but turning it off. The off-state

switch acts like a capacitor and passes higher frequen-

cies with less attenuation. At 1MHz, off-isolation is

about -68dB in 50

Ω systems, becoming worse (approx-

imately 20dB per decade) as the frequency increases.

Higher circuit impedance also degrades off-isolation.

Adjacent channel attenuation is about 3dB above that

of a bare IC socket and is entirely due to capacitive

coupling.

±15kV ESD-Protected, Low-Voltage, CMOS

Analog Multiplexers/Switches

10

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