Datasheet

© 2009 Microchip Technology Inc. DS39755C-page 9
PIC18F2423/2523/4423/4523
1.0 DEVICE OVERVIEW
This document contains device-specific information for
the following devices:
This family offers the advantages of all PIC18
microcontrollers – namely, high computational perfor-
mance at an economical price – with the addition of
high-endurance, Enhanced Flash program memory.
On top of these features, the PIC18F2423/2523/4423/
4523 family introduces design enhancements that
make these microcontrollers a logical choice for many
high-performance, power-sensitive applications.
1.1 New Core Features
1.1.1 nanoWatt TECHNOLOGY
All of the devices in the PIC18F2423/2523/4423/4523
family incorporate a range of features that can signifi-
cantly reduce power consumption during operation.
Key items include:
• Alternate Run Modes: By clocking the controller
from the Timer1 source or the internal oscillator
block, power consumption during code execution
can be reduced by as much as 90%.
• Multiple Idle Modes: The controller also can run
with its CPU core disabled and the peripherals still
active. In these states, power consumption can be
reduced even further, to as little as 4% of normal
operation requirements.
• On-the-Fly Mode Switching: The power-managed
modes are invoked by user code during operation,
allowing the user to incorporate power-saving ideas
into their application’s software design.
• Low Consumption in Key Modules: The power
requirements for both Timer1 and the Watchdog
Timer are minimized. See Section 4.0 “Electrical
Characteristics” for values.
1.1.2 MULTIPLE OSCILLATOR OPTIONS
AND FEATURES
All of the devices in the PIC18F2423/2523/4423/4523
family offer ten different oscillator options, allowing
users a wide range of choices in developing application
hardware. These include:
• Four Crystal modes, using crystals or ceramic
resonators.
• Two External Clock modes, offering the option of
using two pins (oscillator input and a divide-by-4
clock output) or one pin (oscillator input, with the
second pin reassigned as general I/O).
• Two External RC Oscillator modes with the same
pin options as the External Clock modes.
• An internal oscillator block that offers eight clock
frequencies: an 8 MHz clock and an INTRC source
(approximately 31 kHz), as well as a range of six
user-selectable clock frequencies, between
125 kHz to 4 MHz. This option frees the two
oscillator pins for use as additional general
purpose I/O.
• A Phase Lock Loop (PLL) frequency multiplier,
available to both the High-Speed Crystal and
Internal Oscillator modes, allowing clock speeds
of up to 40 MHz from the HS clock source. Used
with the internal oscillator, the PLL gives users a
complete selection of clock speeds, from 31 kHz
to 32 MHz, all without using an external crystal or
clock circuit.
Besides its availability as a clock source, the internal
oscillator block provides a stable reference source that
gives the family additional features for robust
operation:
• Fail-Safe Clock Monitor: Constantly monitors
the main clock source against a reference signal
provided by the internal oscillator. If a clock failure
occurs, the controller is switched to the internal
oscillator block, allowing for continued operation
or a safe application shutdown.
• Two-Speed Start-up: Allows the internal oscillator
to serve as the clock source from Power-on Reset,
or wake-up from Sleep mode, until the primary clock
source is available.
• PIC18F2423 • PIC18LF2423
• PIC18F2523 • PIC18LF2523
• PIC18F4423 • PIC18LF4423
• PIC18F4523 • PIC18LF4523
Note: This data sheet documents only the devices’
features and specifications that are in addition
to, or different from, the features and specifi-
cations of the PIC18F2420/2520/4420/4520
devices. For information on the features and
specifications shared by the PIC18F2423/
2523/4423/4523 and PIC18F2420/2520/
4420/4520 devices, see the “PIC18F2420/
2520/4420/4520 Data Sheet” (DS39631).