MCP4024 MICROCHIP [Microchip Technology], MCP4024 Datasheet - Page 28

• Manufacturer Part Number: MCP4024
• Manufacturer: MICROCHIP [Microchip Technology]

MCP4021/2/3/4
4.2
The MCP4021/2/3/4 device’s WiperLock technology
allows application-specific calibration settings to be
secured in the EEPROM without requiring the use of an
additional write-protect pin.
The WiperLock technology prevents the serial
commands from doing the following:
• Incrementing or decrementing the wiper setting
• Writing the wiper setting to the non-volatile
Enabling and disabling the WiperLock technology
feature
(CS = V
requires high-voltage commands when the feature is
enabled. The high-voltage threshold (V
to prevent the wiper setting from being altered by noise
or intentional transitions on the U/D and CS pins, while
still providing flexibility for production or calibration
environments.
Both the CS and U/D input pins are tolerant of signals
up to 12V. This allows the flexibility to multiplex the
digital pot’s control signals onto application signals for
manufacturing/calibration.
4.3
When the device powers up, the last saved wiper
setting is restored.
While V
may not meet the data sheet specifications (see
Figure
the value stored in the EEPROM. Also the device may
be capable of incrementing, decrementing and writing
to its EEPROM, if a valid command is detected on the
CS and U/D pins.
FIGURE 4-2:
DS21945E-page 28
memory
4-2). The wiper may be unknown or initialized to
IHH
DD
The WiperLock™ Technology
Power-up
requires
). Incrementing and decrementing the wiper
< V
V
min
V
2.7V
V
WP
DD
SS
(2.7V), the electrical performance
high-voltage
Power-up and Brown-out.
serial
IHH
) is intended
Specified AC/DC
commands
Outside
Range
The default settings of the MCP4021/2/3/4 device’s
from the factory are shown in
TABLE 4-1:
It is good practice in your manufacturing flow to
configure the device to your desired settings.
4.4
If the device V
voltage, care must be taken to ensure that the CS and
U/D pins do not “create” any of the serial commands.
When the device V
electrical performance may not meet the data sheet
specifications (see
unknown or initialized to the value stored in the
EEPROM. Also the device may be capable of
incrementing, decrementing and writing to its EEPROM
if a valid command is detected on the CS and U/D pins.
4.5
The serial interface is inactive any time the CS pin is at
V
-202
-502
-103
-503
EEPROM
IH
Protect
Write
and all write cycles are completed.
Mid-scale
Mid-scale
Mid-scale
Mid-scale
Brown Out
Serial Interface Inactive
DD
DEFAULT FACTORY
SETTINGS SELECTION
is below the specified minimum
DD
Figure
1Fh
1Fh
1Fh
1Fh
© 2006 Microchip Technology Inc.
drops below V
4-2). The wiper may be
Table
Disabled
Disabled
Disabled
Disabled
4-1.
min
(2.7V), the
10.0 kΩ
50.0 kΩ
2.1 kΩ
5.0 kΩ