MCP4023 Microchip Technology, MCP4023 Datasheet - Page 41

• Manufacturer Part Number: MCP4023
• Description: Low-Cost NV Digital POT with WiperLock Technology
• Manufacturer: Microchip Technology

5.3
Depending on the requirements of the system, the use
of high voltage (V
required during system operation.
possible system applications, and whether a high
voltage (V
The MCP402X supports six high-voltage commands
(the
specification).
TABLE 5-2:
5.3.1
The circuit in
TC1240A doubling charge pump. When the SHDN pin
is high, the TC1240A is off, and the level on the CS pin
is controlled by the PIC® microcontrollers (MCUs) IO2
pin.
When the SHDN pin is low, the TC1240A is on and the
V
pin to go higher than the voltage such that the PIC
MCU’s IO2 pin “clamps” at approximately V
FIGURE 5-12:
generate the V
© 2006 Microchip Technology Inc.
Production calibration only - system
should not update wiper setting
WiperLock™ Technogy disabled during
system operation
Wiper setting can be updated and
“locked” during system operation
OUT
PIC
voltage is 2 * V
CS
®
MCU
CS High Voltage
IO1
IO2
IHH
System Operation
TECHNIQUES TO FORCE THE CS
PIN TO V
input
) is required on the system.
Figure 5-12
IHH
IHH
HIGH-VOLTAGE
APPLICATIONS
voltage
) on the CS pin, may or may not be
voltage.
DD
R
IHH
Using the TC1240A to
. The resistor R
1
SHDN
V
TC1240A
IN
shows a method using the
V
OUT
must
C
C+
2
C-
meet
CS
Table 5-2
1
allows the CS
MCP402X
Calibration
Required
Required
DD
Voltage
the
From
High
Unit
.
Not
C
1
shows
V
IHH
The circuit in
the MCP402X Non-volatile Digital Potentiometer
Evaluation Board. This method requires that the
system voltage be approximately 5V. This ensures that
when the PIC10F206 enters a brown-out condition,
there is an insufficent voltage level on the CS pin to
change the stored value of the wiper. The MCP402X
Non-volatile Digital Potentiometer Evaluation Board
User’s
schematic.
GP0 is a general purpose I/O pin, while GP2 can either
be a general purpose I/O pin or it can output the internal
clock.
For the serial commands, configure the GP2 pin as an
input (high impedence). The output state of the GP0 pin
will determine the voltage on the CS pin (V
For high-voltage serial commands, force the GP0
output pin to output a high level (V
GP2 pin to output the internal clock. This will form a
charge pump and increase the voltage on the CS pin
(when the system voltage is approximately 5V).
FIGURE 5-13:
Digital Potentiometer Evaluation Board
(MCP402XEV) implementation to generate the
V
IHH
PIC10F206
voltage.
Guide
GP0
GP2
Figure 5-13
MCP4021/2/3/4
(DS51546)
C
1
MCP402X Non-volatile
shows the method used on
contains
R
OH
1
) and configure the
DS21945E-page 41
C
2
CS
MCP402X
a
IL
or V
complete
IH
).