MA180025 Microchip Technology, MA180025 Datasheet - Page 333

• Manufacturer Part Number: MA180025
• Description: MODULE PLUG-IN PIC18F87J90 PIM
• Manufacturer: Microchip Technology
• Series: PIC®r

Specifications of MA180025

• Accessory Type: Plug-In Module (PIM) - PIC18F87J90
• Product: Microcontroller Modules
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC18
• Silicon Core Number: PIC18F
• Silicon Family Name: PIC18FxxJxx
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PICDEM LCD 2 Demonstration Board (DM163030)
• For Use With: DM163030 - KIT DEV PICDEM LCD2
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

25.3
All of the PIC18F87J90 family devices power their core
digital logic at a nominal 2.5V. For designs that are
required to operate at a higher typical voltage, such as
3.3V, all devices in the PIC18F87J90 family incorporate
an on-chip regulator that allows the device to run its
core logic from V
The regulator is controlled by the ENVREG pin. Tying
V
vides power to the core from the other V
the regulator is enabled, a low-ESR filter capacitor
must be connected to the V
(Figure 25-2). This helps to maintain the stability of the
regulator. The recommended value for the filter capac-
itor is provided in Section 28.3 “DC Characteristics:
PIC18F87J90 Family (Industrial)”.
If ENVREG is tied to V
this case, separate power for the core logic at a nomi-
nal 2.5V must be supplied to the device on the
V
levels, typically 3.3V. Alternatively, the V
and V
nominal voltage. Refer to Figure 25-2 for possible
configurations.
25.3.1
When it is enabled, the on-chip regulator provides a
constant voltage of 2.5V nominal to the digital core
logic. The regulator can provide this level from a V
about 2.5V, all the way up to the device’s V
does not have the capability to boost V
2.5V.
In order to prevent “brown-out” conditions when the
voltage drops too low for the regulator, the regulator
enters Tracking mode. In Tracking mode, the regulator
output follows V
100 mV.
The on-chip regulator includes a simple Low-Voltage
Detect (LVD) circuit. If V
approximately 2.45V on V
Low-Voltage Detect Interrupt Flag, LVDIF (PIR2<2>),
and clears the REGSLP (WDTCON<7>) bit, if it was
set.
This can be used to generate an interrupt and put the
application into a low-power operational mode, or trig-
ger an orderly shutdown. Low-Voltage Detection is only
available when the regulator is enabled.
 2010 Microchip Technology Inc.
DD
DDCORE
to the pin enables the regulator, which in turn, pro-
DD
pins can be tied together to operate at a lower
On-Chip Voltage Regulator
/V
CAP
VOLTAGE REGULATION AND
LOW-VOLTAGE DETECTION
pin to run the I/O pins at higher voltage
DD
DD
.
with a typical voltage drop of
SS
DD
, the regulator is disabled. In
DDCORE
drops too low to maintain
, the circuit sets the
DDCORE
DD
DD
DDCORE
levels below
pins. When
/V
DDMAX
CAP
/V
DD
CAP
pin
. It
of
PIC18F87J90 FAMILY
FIGURE 25-2:
Note 1: These are typical operating voltages. For the
Regulator Enabled (ENVREG tied to V
Regulator Disabled (ENVREG tied to ground):
Regulator Disabled (V
2.5V
2.5V
C
full operating ranges of V
refer to Section 28.1 “DC Characteristics:
Supply Voltage PIC18F87J90 Family
(Industrial)”.
(1)
(1)
F
3.3V
3.3V
(1)
CONNECTIONS FOR THE
ON-CHIP REGULATOR
V
ENVREG
V
V
DD
DD
DDCORE
SS
PIC18F87J90
V
ENVREG
V
V
V
ENVREG
V
V
tied to V
DD
DDCORE
SS
DD
DDCORE
SS
PIC18F87J90
PIC18F87J90
/V
CAP
DD
/V
/V
DDCORE
DS39933D-page 333
and V
CAP
CAP
DD
):
DDCORE
):
,