Datasheet

Dual, 256-Tap, Volatile, Low-Voltage,
Linear Taper Digital Potentiometer
MAX5392
12 _____________________________________________________________________________________
Slave Address
The MAX5392 includes a 7-bit slave address (Figure 4).
The 8th bit following the 7th bit of the slave address is the
NOP/W bit. Set the NOP/W bit low for a write command
and high for a no-operation command. The device does
not support readback.
The device provides three address inputs (A0, A1, and
A2), allowing up to eight devices to share a common
bus (Table 1). The first 4 bits (MSBs) of the factory-set
slave addresses are always 0101. A2, A1, and A0 set the
next 3 bits of the slave address. Connect each address
input to V
DD
or GND. Each device must have a unique
address to share a common bus.
Message Format for Writing
Write to the devices by transmitting the device’s slave
address with NOP/W (8th bit) set to zero, followed by
at least 2 bytes of information. The first byte of informa-
tion is the command byte. The second byte is the data
byte. The data byte goes into the internal register of the
device as selected by the command byte (Figure 7 and
Table 2).
Table 1. Slave Addresses
Figure 6. Acknowledge
Figure 7. Command and Single Data Byte Received
9821
START
CONDITION
SCL
SDA
CLOCK PULSE FOR
ACKNOWLEDGMENT
NOT ACKNOWLEDGE
ACKNOWLEDGE
ADDRESS INPUTS
SLAVE ADDRESS
A2 A1 A0
GND GND GND 0101000
GND GND V
DD
0101001
GND V
DD
GND 0101010
GND V
DD
V
DD
0101011
V
DD
GND GND 0101100
V
DD
GND V
DD
0101101
V
DD
V
DD
GND 0101110
V
DD
V
DD
V
DD
0101111
S 0 A A A P
ACKNOWLEDGE
NOP/W
HOW CONTROL BYTE AND DATA
BYTE MAP INTO DEVICE REGISTERS
ACKNOWLEDGE
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
SLAVE ADDRESS COMMAND BYTE 1 DATA BYTE