MCP4431 Microchip Technology Inc., MCP4431 Datasheet - Page 41

• Manufacturer Part Number: MCP4431
• Description: 7/8-bit Volatile Quad Digital Pot With I 2c Interface
• Manufacturer: Microchip Technology Inc.

4.0
This data sheet covers a family of four volatile Digital
Potentiometer and Rheostat devices that will be
referred to as MCP44XX. The MCP44X1 devices are
the Potentiometer configuration, while the MCP44X2
devices are the Rheostat configuration.
As the
main functional blocks. These are:
• POR/BOR and RESET Operation
•
•
• Serial Interface (I2C)
The POR/BOR operation and the Memory Map are
discussed in this section and the Resistor Network and
I
Device Commands
Section 7.0.
4.1
The Power-on Reset is the case where the device is
having power applied to it from V
Reset occurs when a device had power applied to it,
and that power (voltage) drops below the specified
range.
The devices RAM retention voltage (V
than the POR/BOR voltage trip point (V
maximum V
When V
mance may not meet the data sheet specifications. In
this region, the device is capable of incrementing, dec-
rementing, reading and writing to its volatile memory if
the proper serial command is executed.
When V
pin weak pull-ups are enabled.
4.1.1
When the device powers up, the device V
the V
When the V
the following events occur:
• Volatile wiper register is loaded with the default
• TCON registers are loaded with their default value
• Device is capable of digital operation
 2010 Microchip Technology Inc.
2
C operation are described in their own sections. The
Memory Map
Resistor Network
value
POR
Device Block Diagram
DD
POR
FUNCTIONAL OVERVIEW
POR/BOR and RESET Operation
/V
< V
BOR
DD
POWER-ON RESET
POR
/V
BOR
POR
voltage crosses the V
/V
voltage.
BOR
/V
< V
BOR
voltage is less then 1.8V.
DD
commands are discussed in
or the RESET pin is Low, the
< 2.7V, the electrical perfor-
shows, there are four
SS
POR
. The Brown-out
POR
/V
RAM
BOR
/V
DD
) is lower
BOR
voltage,
crosses
). The
4.1.2
When the device powers down, device V
V
When V
voltage, the serial Interface is disabled.
If the V
following events may occur:
• Volatile wiper registers could become corrupted
• TCON registers could become corrupted
As the voltage recovers above the V
the operation is the same as Power-on Reset, as dis-
cussed in the previous subsection.
Serial commands that are not completed because of a
brown-out condition could cause the memory location
to become corrupted.
4.1.3
The RESET pin can be used to force the device into
the POR/BOR state of the device. When the RESET
pin is forced Low, the device is forced into the Reset
state. This means that the TCON registers are forced
to their default values and the volatile wiper registers
are loaded with the default value. Also the I
face is disabled.
This feature allows a hardware method for all registers
to be updated at the same time.
4.1.4
Figure 4-1
POR/BOR signal interact to control the hardware Reset
state of the device.
FIGURE 4-1:
RESET Pin Interaction.
POR
RESET (from pin)
POR/BOR signal
/V
DD
BOR
DD
voltage decreases below V
shows how the RESET pin signal and the
BROWN-OUT RESET
RESET PIN
INTERACTION OF RESET PIN AND
BOR/POR CIRCUITRY
voltage.
voltage decreases below V
MCP443X/5X
POR/BOR Signal and
POR
DS22267A-page 41
Device Reset
RAM
/V
DD
BOR
voltage, the
POR
will cross
2
voltage,
C inter-
/V
BOR