MAX4588
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 COM210
Connects NO6 to COM210
Connects NO7 to COM210
Connects NO8 to COM210
Connect NO1 to COM1 and NO5 to COM2x0
Connects NO1 to COM100
Connects NO2 to COM100
Connects NO3 to COM100
Connects NO4 to COM100
All switches off.x0
Serial Mode. Refer to
Serial Operation
Truth Table
.
x1
SER/PAR
All switches off, latches are cleared.xx
Maintain previous state.x0
SWITCH STATESA2
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
4/
88
Connect NO2 to COM1 and NO6 to COM2x0
Connect NO3 to COM1 and NO7 to COM2x0
Connect NO4 to COM1 and NO8 to COM2x0
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
