Power-On Reset (POR)

The MAX4588 has internal circuitry to guarantee a

known state on power-up. In the default state, A0 = A1

= A2 = 0, disable = 1, and all switches are off. This

state is equivalent to asserting RS during normal opera-

tion.

Serial Operation

The serial mode is activated by driving the SER/PAR

input pin to a logic high. The data is then entered using a

normal SPI/MICROWIRE write operation. Refer to Figure

7 for a detailed diagram of the serial-interface logic.

There are four flip-flops in the shift register, with the out-

put of the fourth shift register being output on the DOUT

pin. Note: DOUT changes on the rising edge of SCLK.

This allows cascading of multiple MAX4588s using only

one chip-select line. For example, one 16-bit write could

load the shift registers of four cascaded MAX4588s. The

data from the shift register is moved to the internal con-

trol latches only upon the rising edge of CS, so all four

MAX4588s change state simultaneously.

Parallel Operation

The parallel mode is activated by driving SER/PAR to a

logic low. The MAX4588 is programmed by a latched

parallel bus scheme. Refer to Figure 6 for a detailed

diagram of the parallel-interface logic. Note that 4/8 is

not latched. It is best to hard-wire 4/8 to a known state

for the desired mode of operation, or to use a dedicat-

ed microcontroller port pin.

Low-Voltage, High-Isolation,

Dual 4-Channel RF/Video Multiplexer

16

______________________________________________________________________________________

Parallel Operation

Connects NO5 to COM2

1

0

Connects NO6 to COM2

1

0

Connects NO7 to COM2

1

0

Connects NO8 to COM2

1

0

Connect NO1 to COM1 and NO5 to COM2

x

0

Connects NO1 to COM1

0

0

Connects NO2 to COM1

0

0

Connects NO3 to COM1

0

0

Connects NO4 to COM1

0

0

All switches off.

x

0

Serial Mode. Refer to

Serial Operation

Truth Table.

x

1

SER/PAR

All switches off, latches are cleared.

x

x

Maintain previous state.

x

0

SWITCH STATES

A2

0

0

1

1

0

0

0

1

1

x

x

x

x

A1

0

1

0

1

0

0

1

0

1

x

x

x

x

A0

1

1

1

1

1

1

1

1

1

0

x

x

x

EN

0

0

0

0

0

0

0

0

0

0

x

x

1

LE

1

1

1

1

1

1

1

1

1

1

1

0

1

RS

0

0

0

0

1

0

0

0

0

x

x

x

x

8

Connect NO2 to COM1 and NO6 to COM2

x

0

Connect NO3 to COM1 and NO7 to COM2

x

0

Connect NO4 to COM1 and NO8 to COM2

x

0

0

1

1

1

0

1

1

1

1

0

0

0

1

1

1

1

1

1

x = Don’t Care

Note: 4/8 is not latched when LE is high. When LE is low, all latches are transparent. A2, A1, A0, and EN are latched.

Connect COM1 to COM2 externally for 1-of-8 single-ended operation.

Truth Tables