Serially Controlled, Clickless

Audio/Video Switches

10

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Detailed Description

The MAX4562/MAX4563 are serial-interface controlled

switches with soft-mode “clickless” and hard-mode oper-

ating capability. The MAX4562/MAX4563 contain two

SPST switches and two SPDT switches. The SPDT

switches are actually 2-to-1 multiplexers, in that each

SPDT is really two independent SPST switches with a

common node, as shown in the

switch is controlled independently by either the 2-wire

ible serial interface.

Audio off-isolation and crosstalk is -85dB at 20kHz.

Video off-isolation and crosstalk is at least -55dB at

10MHz.

Each switch of either device may be set to operate in

either soft or hard mode. In soft mode, the switching

transition is slowed to avoid the audible “clicking” that

can occur when switches are used to route audio sig-

nals. In hard mode, the switches are not slowed down,

making this mode useful when a faster response is

required. If a new command is issued while any soft-

mode switch is transitioning, the switch transition time is

decreased so it reaches its final state before the new

command is executed. Soft mode and open are the

power-up default states for all switches. Switches in the

same mode are guaranteed to be break-before-make

relative to each other. Break-before-make does not apply

between switches operating in different modes.

These devices operate from a +2.7V to +5.5V single

serial interface, and the MAX4563 features a 3-wire

SPI/QSPI/MICROWIRE-compatible serial interface.

SCL

SDA

START CONDITION

STOP CONDITION

REPEATED START CONDITION

START CONDITION

20%

70%

20%

70%

20%

70%

20%

70%

20%

70%

20%

70%

20%

70%

70%

20%

70%

70%

70%

Figure 3. 2-Wire Serial-Interface Timing Diagram

START CONDITION

STOP CONDITION

COMMAND BYTE

SLAVE ADDRESS BYTE

SCL

SDA

MSB

MSB

LSB

LSB

ACK

ACK

Figure 4. A Complete 2-Wire Serial-Interface Transmission