PIC18F4423-I/ML - 8-bit 40MHz 16KB Flash MCU 44-QFN | Microchip
MPN: PIC18F4423-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.42 | $6.42 |
| 10 | $5.78 | $57.80 |
| 100 | $5.16 | $516.00 |
| 500 | $4.62 | $2,310.00 |
| 1,000 | $4.05 | $4,050.00 |
PIC18F4423-I/ML Overview
A PIC18F microcontroller is an 8-bit RISC CMOS MCU built around an enhanced Harvard architecture with a 16-bit instruction word. Within the broader taxonomy, PIC18F sits under Microcontrollers -> Integrated Circuits -> Semiconductors, and is the mid-range performance tier above PIC16F and below the dsPIC33/PIC24 16-bit families. PIC18F parts are widely used where deterministic real-time control, generous peripheral integration and easy in-circuit reprogrammability are required.
Key features of the PIC18F4423-I/ML include 256 bytes of EEPROM data memory, two 8-bit and three 16-bit timers, two capture/compare/PWM modules, a master synchronous serial port (SSP) supporting SPI and I2C, an enhanced USART, dual analog comparators, and nanoWatt Technology for low-power sleep and idle modes. The 12-bit A/D converter delivers 12-channel acquisition for sensor readout and motor-control feedback. The wide operating temperature range (industrial -40C to +85C) suits factory and outdoor equipment.
The architecture uses a 16-bit instruction path with an 8-bit data path, providing up to 10 MIPS throughput at 40 MHz. The flash program memory supports self-programming under bootloader control, allowing field firmware updates over UART or USB. nanoWatt Technology provides dynamic clock switching, sleep/idle modes with sub-microamp currents, and oscillator start-up timers for battery-aware designs.
Typical applications include industrial sensor monitoring, HVAC control panels, low-end motor control, instrumentation with analog front-ends, and consumer appliance control boards. The 12-bit ADC plus capture/PWM make it well-suited to closed-loop feedback systems. This device pairs naturally with PIC18F-series companions such as PIC18F4420 (smaller memory variant) or PIC18F4520 (32 KB flash sibling) for scalable product platforms.
When designing with the PIC18F4423-I/ML, ensure decoupling (100 nF + 10 uF bulk) is placed close to VDD/VSS pairs and respect the 44-QFN thermal pad soldering guidelines (IPC-7351 land pattern). Plan the trace routing so that the analog AVdd/AVss pair is filtered with a ferrite bead to preserve ADC SNR at full 12-bit resolution. The Industrial (-I) temperature grade covers -40C to +85C, which satisfies most non-automotive embedded-control use cases.
This page synthesizes distributor pricing, drop-in PIC18F alternatives, package-level pinout guidance and practical design notes that are not compiled in the manufacturer datasheet alone, giving engineers a faster path from datasheet review to prototype.
Drop-in alternatives for PIC18F4423-I/ML — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with PIC18F4423-I/ML (same form factor and footprint) — differing in Operating Temperature, Package, ADC, Core Architecture, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4520-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4423-E/ML
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC18F4420-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4423T-I/ML
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18F4331-I/ML
✅ Drop-In✓ In Stock
$5.32 / Unit
View Datasheet →PIC18F4423-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18F (8-bit RISC, enhanced Harvard) |
| Maximum CPU Clock | 40 MHz (10 MIPS) |
| Instruction Execution Time | 200 ns (at 40 MHz) |
| Program Memory (Flash) | 16 KB (8K x 16) |
| Data SRAM | 768 bytes |
| Data EEPROM | 256 bytes |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| Digital I/O Pins | 36 |
| ADC Channels | 12 (max) |
| Timers | 2 x 8-bit + 3 x 16-bit |
| Capture/Compare/PWM | 2 modules |
| Serial Interfaces | SSP (SPI / I2C), Enhanced USART |
| Analog Comparators | 2 |
| Low-Power Modes | nanoWatt Technology (Sleep, Idle, dynamic clock switching) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | 44-pin QFN (8 x 8 mm) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
PIC18F4423-I/ML Pin Configuration
| Pin 1 | MCLR/RE3 — Master Clear (reset) input or digital I/O RE3 |
| Pin 2 | RA0/AN0 — Digital I/O RA0 / analog input AN0 |
| Pin 3 | RA1/AN1 — Digital I/O RA1 / analog input AN1 |
| Pin 4 | RA2/AN2/VREF- — Digital I/O RA2 / AN2 / negative analog reference |
| Pin 5 | RA3/AN3/VREF+ — Digital I/O RA3 / AN3 / positive analog reference |
| Pin 6 | RA4/T0CKI — Digital I/O RA4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — Digital I/O RA5 / AN4 / SPI slave select |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RA7/OSC1 — Digital I/O RA7 / crystal oscillator input |
| Pin 10 | RA6/OSC2 — Digital I/O RA6 / crystal oscillator output |
| Pin 11 | RC0/T1CKI — Digital I/O RC0 / Timer1 clock input |
| Pin 12 | RC1/CCP2 — Digital I/O RC1 / CCP2 PWM output |
| Pin 13 | RC2/CCP1 — Digital I/O RC2 / CCP1 PWM output |
| Pin 14 | RC3/SCK/SCL — Digital I/O RC3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — Digital I/O RC4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — Digital I/O RC5 / SPI data out |
| Pin 17 | RC6/TX/CK — Digital I/O RC6 / USART TX / clock |
| Pin 18 | RC7/RX/DT — Digital I/O RC7 / USART RX / data |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply (4.2 V to 5.5 V) |
| Pin 21 | RB0/INT0/FLT0 — Digital I/O RB0 / external interrupt 0 / PWM fault |
| Pin 22 | RB1/INT1 — Digital I/O RB1 / external interrupt 1 |
| Pin 23 | RB2/INT2 — Digital I/O RB2 / external interrupt 2 |
| Pin 24 | RB3/INT3/CCP2 — Digital I/O RB3 / external interrupt 3 / CCP2 alternate |
| Pin 25 | RB4 — Digital I/O RB4 |
| Pin 26 | RB5 — Digital I/O RB5 |
| Pin 27 | RB6/PGC — Digital I/O RB6 / ICSP clock |
| Pin 28 | RB7/PGD — Digital I/O RB7 / ICSP data |
| Pin 29 | VSS — Ground reference |
| Pin 30 | VDD — Positive supply (4.2 V to 5.5 V) |
| Pin 31 | RD0 — Digital I/O RD0 |
| Pin 32 | RD1 — Digital I/O RD1 |
| Pin 33 | RD2 — Digital I/O RD2 |
| Pin 34 | RD3 — Digital I/O RD3 |
| Pin 35 | RD4 — Digital I/O RD4 |
| Pin 36 | RD5 — Digital I/O RD5 |
| Pin 37 | RD6 — Digital I/O RD6 |
| Pin 38 | RD7 — Digital I/O RD7 |
| Pin 39 | VSS — Ground reference |
| Pin 40 | VDD — Positive supply (4.2 V to 5.5 V) |
| Pin 41 | RE0/RD — Digital I/O RE0 / parallel-port read control |
| Pin 42 | RE1/WR — Digital I/O RE1 / parallel-port write control |
| Pin 43 | RE2/CS — Digital I/O RE2 / parallel-port chip-select |
| Pin 44 | PAD (EP) — Exposed thermal pad - tie to VSS per QFN PCB layout |
Typical Applications
PIC18F4423-I/ML is suitable for 6 applications: Industrial Sensor Monitoring, HVAC Control Panels, Low-End Motor Control, Instrumentation with Analog Front-End, Consumer Appliance Control Boards, Battery-Backed Sensor Hubs.
Industrial Sensor Monitoring
The PIC18F4423-I/ML fits industrial sensor monitoring because its 12-channel A/D converter (10- or 12-bit per family datasheet), 36 I/O pins and 4.2V-5.5V supply match the typical 5 V sensor-front-end environment. The 40 MHz / 10 MIPS core handles multi-channel scan loops and on-chip averaging in real time, while 256 bytes of EEPROM stores calibration constants and unit IDs across 1 M erase/write cycles. Place the device between a 5 V regulated rail and the analog signal chain, with AVdd filtered through a ferrite bead and a 100 nF + 10 uF decoupling pair. Trade-off: the 5 V-only supply rules out single-cell Li-Ion battery operation - for that, migrate to PIC18LF4423.
Recommended
HVAC Control Panels
In HVAC control panels the PIC18F4423-I/ML drives the user interface, reads temperature/pressure sensors and switches relays/triacs through its PWM and digital I/O. The two CCP modules generate PWM for fan-speed control and valve actuation, while the 12-channel ADC handles multiple thermistor and 0-10 V pressure inputs. Industrial -40C to +85C temperature grade and nanoWatt low-power modes support unattended equipment installations. A typical design uses the UART for a Modbus RTU link to a building controller. Trade-off: 16 KB flash is tight for complex GUI bitmaps - choose PIC18F4520 (32 KB) if you need a graphical LCD interface.
Recommended
Low-End Motor Control
For low-end motor control such as small DC, BLDC or stepper drives, the PIC18F4423-I/ML provides two CCP modules for PWM generation and a 40 MHz core for commutation and current-loop math. The two analog comparators can implement overcurrent protection by directly tripping the PWM shutdown path. For higher-end motor control, however, PIC18F4331 is a drop-in replacement in the same 44-QFN footprint and adds dedicated motor-control PWM and quadrature encoder inputs. Trade-off: PIC18F4423 lacks the dedicated motion-control peripherals of PIC18F4331, so design complexity stays low but feature ceiling is also low.
Recommended
Instrumentation with Analog Front-End
Bench-top and portable instrumentation benefits from the PIC18F4423-I/ML's 12-channel ADC, dual analog comparators and flexible SSP for SPI/IC sensor front-ends. The enhanced USART links the instrument to a host PC or display, and 256 bytes of EEPROM retain user calibration and serial numbers. Industrial temperature grade supports lab and field use, while nanoWatt technology minimizes heat and battery drain during handheld operation. Place the device near the analog conditioning chain with a star-ground layout. Trade-off: 16 KB flash is enough for acquisition logic but limited for on-board DSP - pair with an external dsPIC33 if FFT or filtering is needed.
Recommended
Consumer Appliance Control Boards
Consumer appliances such as washing machines, dishwashers, ovens and coffee machines use the PIC18F4423-I/ML for keypad reading, LED/LCD display driving, motor/PWM control and safety interlocks. The 36 I/O pins cover multiple 7-segment displays and key matrices without external expanders. Two CCP modules drive buzzer tones or triac-fired heater elements. Industrial -40C to +85C temperature grade tolerates the thermal envelope behind appliance panels. Trade-off: 16 KB flash is constrained for feature-rich appliances with connectivity - pair with a low-cost Wi-Fi module if IoT connectivity is required.
Recommended
Battery-Backed Sensor Hubs
Battery-backed sensor hubs leverage the PIC18F4423-I/ML's nanoWatt technology to keep idle currents under 1 uA while still offering fast wake-up on interrupt. The 256-byte EEPROM retains configuration when the cell is removed. For long-life IoT-style sensor nodes running from a single-cell Li-Ion, however, migrate to PIC18LF4423 (LF variant) which operates down to 2.0 V; the standard -4423 minimum 4.2 V supply rules out direct Li-Ion use. Trade-off: not the lowest-power PIC family - PIC16F1xxx or PIC24 offer stronger nanoWatt specs if multi-year coin-cell life is mandatory.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4423-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4520-I/ML | PIC18F4423-E/ML | PIC18F4420-I/ML | PIC18F4331-I/ML |
|---|---|---|---|---|---|
| Package | 44-QFN (8x8) | 44-QFN (8x8) | 44-QFN (8x8) | 44-QFN (8x8) | 44-QFN (8x8) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum Clock | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Supply Voltage | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V |
| Temperature Grade | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Extended (-40C to +125C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) |
| Special Feature | nanoWatt Technology | nanoWatt Technology | nanoWatt Technology | nanoWatt Technology | Motor-control PWM + QEI |
Key Differentiators
- 16 KB flash with 768-byte RAM in 44-QFN footprint (vs PIC18F4331-I/ML)
- Same-package flash upgrade path (vs PIC18F4520-I/ML)
- Extended-temperature option without layout change (vs PIC18F4423-E/ML)
- NanoWatt Technology integrated on this family (vs PIC16F877A-I/P)
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible to each VDD/VSS pair (pins 20, 30, 40 and pins 8, 19, 29, 39), and add a 10 uF bulk tantalum or ceramic near the IC. For the analog AVdd/AVss pair, route AVdd through a ferrite bead fed from VDD to keep digital switching noise out of the ADC reference. This is essential because the 12-bit ADC has only +/-1 LSB tolerance for full-resolution reads.
The 44-QFN (8x8 mm) exposed thermal pad (pin 44) must be soldered to a copper pour on the PCB per IPC-7351 land-pattern guidelines. Estimated: with theta_JA around 30-35 C/W on a 4-layer 1 oz PCB, this package dissipates roughly 1 W at 50 C ambient. Insufficient thermal pad soldering raises junction temperature and risks thermal-shutdown nuisance trips in motor-control and PWM-heavy designs.
Keep crystal traces (OSC1/OSC2, pins 9 and 10) short, symmetrical and surrounded by a ground guard ring to reduce EMI pickup. Place MCLR (pin 1) pull-up within 1 cm of the pin to avoid in-circuit programming noise. Route the ICSP pins RB6/PGC and RB7/PGD directly to a 0.1 inch header for clean MPLAB PICkit 5 programming. Use a star-ground topology: digital VSS and analog AVss tied at one point near the IC.
The PIC18F4423 ADC can achieve its full 12-bit resolution only when the analog source impedance is below 2.5 kohm per Microchip datasheet ac electrical specifications. Add an op-amp buffer (e.g. MCP6001) for higher-impedance sensors, or add external sample capacitors. For 10-bit applications the 2.5 kohm limit is more relaxed but still important at high source impedances.
Do not assume 5 V-tolerant operation on any pin - all I/O are 0 to VDD only. Confirmed pitfalls: (1) leaving the MCLR pin floating during power-up causes spurious resets - always add the 10 kohm pull-up; (2) oscillator start-up timer needs to be honored with correct configuration word OSCCON settings; (3) on 44-QFN, forgetting to solder the thermal pad leads to thermal-failure in motor-control duty cycles. Refer to the Microchip PIC18F4423 datasheet (DS39631E) configuration word section before firmware bring-up.
Compliance Information
RoHS and REACH compliant per Microchip product page. Industrial -40C to +85C temperature grade; not AEC-Q100 qualified - choose PIC18F4423-E/ML (-40C to +125C extended) or AEC-Q100 qualified variant for automotive applications.
