MCP40D17 Microchip Technology Inc., MCP40D17 Datasheet - Page 31

• Manufacturer Part Number: MCP40D17
• Description: 7-bit Single I 2 C? With Command Code Digital Pot With Volatile Memory In Sc70
• Manufacturer: Microchip Technology Inc.

4.0
The MCP40D17/18/19 devices are general purpose
digital potentiometers intended to be used in
applications where a programmable resistance with
moderate bandwidth is desired.
This Data Sheet covers a family of three Digital
Potentiometer and Rheostat devices. The MCP40D18
device is the Potentiometer configuration, while the
MCP40D17 and MCP40D19 devices are the Rheostat
configuration.
Applications generally suited for the MCP40D17/18/19
devices include:
• Computer Servers
• Set point or offset trimming
• Sensor calibration
• Selectable gain and offset amplifier designs
• Cost-sensitive mechanical trim pot replacement
As the
main functional blocks. These are:
•
•
•
The POR/BOR operation and the Memory Map are
discussed in this section and the I
Network operation are described in their own sections.
The
Section 5.4.
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
electrical performance may not meet the data sheet
specifications. In this region, the device is capable of
reading and writing to its volatile memory if the proper
serial command is executed.
Table 4-1
across the entire V
the Power-up and Brown-out functionality.
© 2009 Microchip Technology Inc.
POR/BOR Operation
Serial Interface - I
Resistor Network
Serial Commands
Device Block Diagram
POR
GENERAL OVERVIEW
POR/BOR Operation
shows the digital pot’s level of functionality
/V
POR
BOR
/V
BOR
< V
DD
2
range, while
DD
C Module
voltage is less than 1.8V.
< 2.7V, the Resistor Network’s
commands are discussed in
shows, there are four
Figure 4-1
SS
2
. The Brown-out
C and Resistor
POR
RAM
/V
) is lower
BOR
illustrates
). The
4.1.1
When the device powers up, the device V
the V
the V
• Volatile wiper register is loaded with the default
• The device is capable of digital operation
4.1.2
When the device powers down, the device V
cross the V
decreases below the V
happens:
• Serial Interface is disabled
If the V
the following happens:
• Volatile wiper registers may become corrupted
As the voltage recovers above the V
see Section 4.1.1 “Power-on Reset”.
Serial commands not completed due to a Brown-out
condition may cause the memory location to become
corrupted.
4.1.3
The Wiper Register is volatile memory that starts
functioning at the RAM retention voltage (V
Wiper Register will be loaded with the default wiper
value when V
4.1.4
The current of the device can be classified into two
modes of the device operation. These are:
• Serial Interface Inactive (Static Operation)
• Serial Interface Active
Static Operation occurs when a Stop condition is
received. Static Operation is exited when a Start
condition is received.
wiper value (3Fh)
POR
POR
DD
/V
/V
MCP40D17/18/19
voltage decreases below the V
BOR
BOR
POWER-ON RESET
BROWN-OUT RESET
WIPER REGISTER (RAM)
DEVICE CURRENTS
POR
DD
voltage. Once the V
/V
voltage, the following happens:
will rise above the V
BOR
voltage. Once the V
POR
/V
BOR
voltage the following
DD
POR
POR
DS22152B-page 31
voltage crosses
/V
/V
BOR
DD
RAM
BOR
DD
RAM
will cross
voltage.
voltage
voltage
voltage
DD
). The
will