Low-Resistance DPDT Switches

with Negative Rail

2

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Detailed Description

The MAX14535E–MAX14539E are low on-resistance

and high ESD-protected single DPDT switches that

operate from a +2.4V to +5.5V supply and are

designed to multiplex AC-coupled analog signals.

mance switching applications. The negative signal

capability of the analog channel allows signals below

ground to pass through without distortion.

Analog Signal Levels

The MAX14535E

−MAX14539E are bidirectional, allow-

ing NO_, NC_, and COM_ to be configured as either

inputs or outputs. Note that NC_ and NO_ are only pro-

tected against ESD up to ±2kV (Human Body Model)

and may require additional ESD protection if used as

outputs. These devices feature a charge pump that

generates a negative supply to allow analog signals as

low as -1.5V to pass through NO_, NC_, or COM_. This

allows AC-coupled signals that drop below ground to

pass even when operating from a 3.0V to 5.5V supply.

For the MAX14537E/MAX14538E, the negative charge

pump is controlled by the enable input and is active

when EN is high. When EN is driven low, the negative

charge pump is disabled, which puts the devices in the

lowest possible current consumption, and the signal

active for the MAX14535E/MAX14536E/MAX14539E,

therefore, a negative signal (at most -1.5V) can be

applied through NC_, NO_, or COM_, even when EN is

driven low. A negative rail signal (signal voltage < 0)

must not be applied to the switch unless the negative

charge pump is active.

Digital Control Input

The MAX14535E

−MAX14539E provide a single-bit con-

trol logic input, CB. CB controls the switch position as

shown in the

Functional Diagrams. Drive CB rail-to-rail

to minimize power consumption.

Enable Input

The MAX14535E

−MAX14539E feature a shutdown

mode that reduces the supply current (less than 1µA

for MAX14537E/MAX14538E) and places the switches

in high impedance. Drive EN low to place the device in

shutdown mode. Drive EN high for normal operation.

Shunt Resistors

(MAX14535E/MAX14537E/MAX14539E)

When EN is high, the shunt resistors are controlled by

CB. When CB is low, NC_ is connected to COM_ and

NO_ is connected to shunt resistors. When CB is high,

NO_ is connected to COM_ and NC_ is connected to

shunt resistors (MAX14539E). When EN is low, all the

switches are open and all the shunt resistors are active.

Click-and-Pop Suppression

The 500

Ω shunt resistors on the MAX14535E/

MAX14537E/MAX14539E automatically discharge any

capacitance at the NO_ terminals (or NC_ terminals,

MAX14539E) when they are unconnected from COM_.

This reduces audio click-and-pop sounds that may

occur when switching between capacitively coupled

audio sources.