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MAX14508E

USB 2.0 Hi-Speed and Audio Switches with Negative Signal Capability

Maxim Integrated 

MAX14508E–MAX14511E/

MAX14509AE

USB 2.0 Hi-Speed and Audio Switches

with Negative Signal Capability

Detailed Description

The MAX14508E–MAX14511E/MAX14509AE are high-

ESD-protected single DPDT switches that operate from

a +2.7V to +5.0V supply and are designed to multiplex

USB 2.0 Hi-Speed signals and AC-coupled analog signals.

These switches combine the low on-capacitance (CON)

and low on-resistance (RON) necessary for high-

performance switching applications. These devices meet

the requirements for USB low-speed and full-speed signaling.

The negative signal capability of the analog channel

allows signals below ground to pass through without distortion.

Analog Signal Levels

The MAX14508E–MAX14511E/MAX14509AE are bidirectional,

allowing ANO_, UNC_, and COM_ to be configured as

either inputs or outputs. Note that UNC_ and ANO_ are

only protected 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 VCC - 5.0V to pass through ANO_. This allows

AC-coupled signals that drop below ground to pass when

operating from a single power supply. The negative charge

pump is controlled by the enable line and the output of the

COM_ fault protection circuit. The negative charge pump

is active when EN is high and VCOM_ < VFP. Note that if

the fault protection is activated by a COM_ voltage greater

than VFP, there must not be a negative voltage attached

to the ANO_ inputs. For the MAX14508E/MAX14509E/

MAX14509AE connect negative signals to ANO_ or

COM_ only when EN is driven high.

Overvoltage Fault Protection

The MAX14508E–MAX14511E feature overvoltage

fault protection on COM_, allowing compliance with

USB requirements for voltage levels. Fault protection is

triggered if the voltage applied to COM_ rises above VFP,

protecting the switch and USB transceiver from damaging

voltage levels.

VBUS Detection Input

The MAX14510E/MAX14511E feature a VBUS detection

input (VB) that connects COM_ to UNC_ when VVB

exceeds the VBUS detection threshold (VVBDET). For

applications where VBUS is always present, drive the

Audio Override Input (AOR) high to connect ANO_ to

COM_ (see the MAX14510E/MAX14511E Functional

Diagrams/Truth Table). Drive AOR low to have VB

control the switch position. Drive AOR rail-to-rail to

minimize power consumption.

Digital Control Input (CB)

The MAX14508E/MAX14509E/MAX14509AE provide a

single-bit control logic input, CB. CB controls the switch

position as shown in the MAX14508E/MAX14509E/

MAX14509AE Functional Diagrams/Truth Table. Drive

CB rail-to-rail to minimize power consumption.

Enable Input (EN)

The MAX14508E/MAX14509E/MAX14509AE feature a

shutdown mode that reduces the supply current to less

than 10nA and places the switches in high impedance.

Drive EN low to place the devices in shutdown mode.

Drive EN high for normal operation.

Click-and-Pop Suppression

The switched 100Ω shunt resistors on the MAX14508E/

MAX14510E automatically discharge any capacitance

at the ANO_ terminals when they are unconnected from

COM_. This reduces audio click-and-pop sounds that may

occur when switching between USB and audio sources.

Applications Information

Extended ESD Protection

ESD-protection structures are incorporated on all pins

to protect against electrostatic discharges up to ±2kV

(Human Body Model) encountered during handling and

assembly. COM1 and COM2 are further protected against

ESD up to ±15kV (Human Body Model) without damage.

The ESD structures withstand high ESD both in

normal operation and when the device is powered

down. After an ESD event, the MAX14508E–MAX14511E/

MAX14509AE continue to function without latchup.

ESD Test Conditions

ESD performance depends on a variety of conditions.

Contact Maxim for a reliability report that documents test

setup, test methodology, and test results.

Human Body Model

Figure 5 shows the Human Body Model. Figure 6 shows

the current waveform it generates when discharged into a

low impedance. This model consists of a 100pF capacitor

charged to the ESD voltage of interest that is then dis-

charged into the device through a 1.5kΩ resistor.

Layout

USB Hi-Speed requires careful PCB layout with 45Ω

single-ended/90Ω differential controlled-impedance

matched traces of equal lengths. Ensure that bypass

capacitors are as close to the device as possible. Use

large ground planes where possible.

www.maximintegrated.com

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