Datasheet
MAX4548/MAX4549
Serially Controlled, Triple 3x2 Audio/Video
Crosspoint Switches
______________________________________________________________________________________ 13
Table 3. Bias Data-Byte (C6 = “1”)
1Controls NO2B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D3
1Controls NO2A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D2
1Controls NO1B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D1
1Controls NO1A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D0
1Controls SB bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D7
1Controls SA bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D6
1Controls NO3B bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D5
1Controls NO3A bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D4
1Controls SC bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D11
1Controls NO3C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D10
1Controls NO2C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D9
1Controls NO1C bias resistors; 1 = connect bias resistors, 0 = disconnect bias resistors.D8
–Don’t careD12
–Don’t careD13
BIT
–
DESCRIPTION
D14
–
Don’t care
D15
POWER-UP
DEFAULT
STATE
Don’t care
SCL
AB CD
E
FG
H
I
J
SDA
t
SU:STA
t
HD:STA
t
LOW
t
HIGH
t
SU:DAT
t
HD:DAT
t
SU:STO
t
BUF
A = START CONDITION
B = MSB OF ADDRESS BYTE
C = LSB OF ADDRESS BYTE
D = ACKNOWLEDGE CLOCKED INTO MASTER
E = MSB OF COMMAND BYTE
F = LSB OF COMMAND BYTE
G = ACKNOWLEDGE CLOCKED INTO MASTER
H = MSB OF DATA BYTE/WORD
I = LSB OF DATA BYTE/WORD
J = ACKNOWLEDGE CLOCKED INTO MASTER
Figure 5. 2-Wire Serial-Interface Timing Details
Command-Byte and Data-Byte
Programming
The devices are programmed with a command byte and
a data byte or data word (2 bytes). Each bit of the
command byte selects one of the functional blocks to be
controlled by the subsequent data byte (word). The data
byte (word) sets the state of the selected block(s). For
the three switch-matrix blocks, the data byte sets the
switch state. For the bias-resistor block, the data word
controls which bias network is active (see
Functional
Diagram
).
A logic “1” in any bit position of the data byte makes
that function active, while a logic “0” makes it inactive.
Tables 1–4 describe the command byte and the corre-
sponding data byte. If more than one bit of the com-
mand byte is set, the data byte programs all of the
corresponding blocks. This operation is useful, for
instance, to simultaneously set all switch matrices to