Microchip Technology

PIC18LF4523-I/ML - 8-bit 40MHz 32KB FLASH MCU | Microchip

MPN: PIC18LF4523-I/ML ✓ Active
In Stock Ships in 1-3 business days
2.0 V to 5.5 V Vdss 44-QFN (8x8 mm) with exposed pad Package 40 MHz Speed 32 KB (16K x 16) Memory
From $4.12 USD / Unit
MOQ: 1 |
Price updated: 2026-09-28
Volume Pricing
Qty Unit Price Extended
1 $7.42 $7.42
10 $6.78 $67.80
100 $6.04 $604.00
500 $5.21 $2,605.00
1,000 $4.58 $4,580.00
2,500 $4.12 $10,300.00
ℹ️ All prices are in USD

PIC18LF4523-I/ML Overview

The Microchip Technology PIC18LF4523-I/ML is an 8-bit PIC18F-family microcontroller (MCU) with a 40 MHz CPU core, 32 KB (16K x 16) of FLASH program memory, 1536 bytes of SRAM and 256 bytes of EEPROM, housed in a 44-pin QFN (8x8 mm) package with exposed thermal pad. The "LF" prefix indicates a wide-range low-voltage core that operates from 2.0 V to 5.5 V, and the "-I" suffix designates the industrial temperature grade of -40 °C to +85 °C.

A microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory (FLASH/ROM), working RAM, peripherals (timers, ADC, communication ports, PWM, comparators) and interrupt logic on one silicon die. PIC microcontrollers use a RISC (Reduced Instruction Set Computer) architecture with a 16-bit instruction word and 8-bit data path, executing most instructions in one instruction cycle (4 oscillator clocks). The PIC18 family sits between PIC16 mid-range and PIC24 16-bit dsPIC families in Microchip's portfolio, balancing code density, peripheral richness and 5 V analog performance. The PIC18LF4523 belongs to the PIC18F4523 sub-family of general-purpose devices with full-speed USB 2.0 (Full-Speed, 12 Mbps), making it a true "system-on-a-chip" for embedded control.

Key differentiating features include 36 digital I/O pins across five ports (RA, RB, RC, RD, RE), a 13-channel 12-bit ADC, two analog comparators, two CCP modules plus one ECCP for enhanced PWM, two UART/USART channels, one SPI and one I2C (MSSP) peripheral, a 16-bit timer/counter and three 8-bit timers, plus an on-chip full-speed USB 2.0 device/host/OTG transceiver. The device also provides 10 MIPS sustained throughput, hardware multiplier, two 8-bit hardware multipliers and a programmable brown-out reset (BOR) and low-voltage detect (LVD).

The PIC18LF4523 uses an enhanced Harvard architecture with separate program and data buses, a hardware 8x8 single-cycle multiplier, and Microchip's nanoWatt Technology dynamic power management. Self-programmability of the FLASH via ICSP (In-Circuit Serial Programming) and runtime by the user firmware is supported, enabling bootloader-based field upgrades. The USB SIE is fully on-chip, eliminating an external PHY and reducing BOM cost for HID, CDC, vendor-class and mouse/keyboard applications.

Typical applications include USB peripherals (HID mice, keyboards, custom HID controllers, USB-to-serial bridges), industrial control panels (sensor interfaces, motor drive logic, Modbus gateways), home appliances (washing machines, microwave ovens, induction cookers, HVAC controllers), automotive interior subsystems (instrument clusters, climate control, lighting) and low-power data loggers with USB connectivity. The wide 2.0 V to 5.5 V range also lets it run directly from a single Li-ion cell or from a 3.3 V regulated rail.

When designing with this device, route the exposed thermal pad (EP) of the QFN-44 to a continuous ground plane with multiple thermal vias, because the EP is the primary heat-dissipation path. Keep the USB D+/D- traces length-matched within 150 mil and keep them away from switching nodes such as PWM outputs to preserve USB signal integrity. Decouple VDD/VSS with a 100 nF X7R placed within 3 mm of each power pin, and place the 4.7 uF bulk capacitor adjacent to the QFN package.

This page synthesizes distributor pricing (DigiKey, Mouser, Octopart), pin-compatible 44-QFN drop-in alternatives, and practical USB layout and thermal notes that go beyond the manufacturer datasheet summary.

Drop-in alternatives for PIC18LF4523-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 PIC18LF4523-I/ML (same form factor and footprint) — differing in Package, Timers, ADC, Core, MSL Level.

Microchip Technology
Package: 28-pin QFN (6x6 mm) with exposed thermal pad
Timers: 4 (8-bit / 16-bit mix)
ADC: 10-bit, up to 12 channels
Microchip Technology
Package: 44-pin QFN (HVQCCN) 8x8 mm with exposed pad
Timers: Multiple 8-bit and 16-bit
ADC: 10-bit, up to 13 channels
Microchip Technology
Package: 44-pin QFN (8x8 mm) with exposed thermal pad
Timers: 1x 8-bit, 3x 16-bit
MSL Level: 3 (168 hours)
Microchip Technology
Package: 40-pin PDIP (0.600")
ADC: 12-channel, 10-bit
Core: PIC18 (8-bit RISC)
Microchip Technology
Package: TQFP-44 (10x10 mm)
Timers: 4 (Timer0, Timer1, Timer2, Timer3)
ADC: 13 channels x 12-bit
Microchip Technology
Package: 44-QFN (8x8 mm)
Timers: 2 x 8-bit, 3 x 16-bit
ADC: 10-bit, up to 13 channels
Microchip Technology
Package: 44-TQFP (PT) 10x10 mm
Timers: 4 x 16-bit
ADC: 10-bit, up to 13 channels
Microchip Technology
Package: 44-pin QFN (ML) with exposed pad
ADC: 10-bit, multi-channel
Core: PIC18 (8-bit, 16-bit instruction word)
Microchip Technology
Package: 44-pin QFN-EP (8x8 mm)
Timers: 4 (8-bit/16-bit selectable)
ADC: 10-bit, up to 13 channels

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

PIC18LF4523-I/PT

✅ Drop-In ⚠️ Specs Unverified
Microchip Technology
📦 44-TQFP (PT)
PIC18 (8-bit RISC, modified Harvard) · 32 KB (16K x 16) · 1536 bytes · 256 bytes · 40 MHz (10 MIPS) · 2.0 V to 5.5 V (4.2 V to 5.5 V at 40 MHz; down to 2.0 V at 4 MHz) · 36 · 13 channels x 12-bit

✓ In Stock

$5 / Unit

View Datasheet →

PIC18LF4523T-I/ML

✅ Drop-In
Microchip Technology
📦 44-QFN (ML)
PIC18F · 8-bit PIC RISC · 32 KB (16K x 16) · 1536 bytes · 256 bytes · 40 MHz · 2.0 V to 5.5 V · -40°C to +85°C (Industrial)

✓ In Stock

$5.95 / Unit

View Datasheet →

PIC18LF4520-I/ML

✅ Drop-In
Microchip Technology
📦 44-QFN (ML)
PIC18, 8-bit Harvard RISC · 40 MHz (10 MIPS) · 200 ns (at 40 MHz) · 32 KB (16K x 16) · 1536 bytes · 256 bytes · 36 · 10-bit, up to 13 channels

✓ In Stock

$4.92 / Unit

View Datasheet →

PIC18LF2523-I/ML

✅ Drop-In ⚠️ Specs Unverified
Microchip Technology
📦 44-QFN (ML)
PIC18 (Enhanced Harvard RISC, 8-bit) · 40 MHz (10 MIPS) · 32 KB (16K x 16) · 1536 bytes · 256 bytes · 2.0 V to 5.5 V · -40 C to +85 C · 25

✓ In Stock

$3.65 / Unit

View Datasheet →

PIC18LF4523-I/P

✅ Drop-In
Microchip Technology
📦 40-DIP (P)
PIC18 (8-bit RISC) · 40 MHz (10 MIPS) · 32 KB (16K x 16) · 1536 bytes · 256 bytes · 2.0 V to 5.5 V · 36 · 12-channel, 10-bit

✓ In Stock

$4.32 / Unit

View Datasheet →

PIC18LF4523-I/ML Maximum Ratings & Electrical Characteristics

Product Family PIC18F
Core PIC 8-bit RISC
Core Width 8-bit
Maximum CPU Frequency 40 MHz
Instruction Throughput 10 MIPS
Program Memory (FLASH) 32 KB (16K x 16)
Data EEPROM 256 bytes
Data SRAM 1536 bytes
Operating Voltage (Vdd) 2.0 V to 5.5 V
I/O Pins 36
ADC 13-channel, 12-bit
USB USB 2.0 Full-Speed (12 Mbps) Device/Host/OTG on-chip SIE
Timers 1 x 16-bit, 3 x 8-bit
CCP / ECCP 2 CCP, 1 ECCP
Comparators 2 analog comparators
Communication 2x UART, 1x SPI, 1x I2C (MSSP)
Package 44-QFN (8x8 mm) with exposed pad
Mounting Type Surface Mount
Operating Temperature -40 C to +85 C (Industrial)
RoHS Status Compliant
Lead-Free / Halogen-Free Lead-Free / Halogen-Free (per Microchip)

PIC18LF4523-I/ML Pin Configuration

Generic Component Pin Configuration Generic integrated-circuit pinout placeholder. Pin 1 indicated by dot; exact pin count and functions in the pin table below. 1 N 2 N-1 3 N-2 4 N-3 Pin Configuration See pin table below for pin functions Package-specific diagram not available
Pin 1 MCLR/VPP/RE3 — Master Clear (reset) input / programming voltage / digital I/O RE3
Pin 2 RA0/AN0 — PORTA bit 0 / analog input AN0
Pin 3 RA1/AN1 — PORTA bit 1 / analog input AN1
Pin 4 RA2/AN2/VREF- — PORTA bit 2 / analog input AN2 / ADC VREF-
Pin 5 RA3/AN3/VREF+ — PORTA bit 3 / analog input AN3 / ADC VREF+
Pin 6 RA4/T0CKI/C1OUT — PORTA bit 4 / Timer0 clock input / comparator 1 output
Pin 7 RA5/AN4/SS/C2OUT — PORTA bit 5 / analog input AN4 / SPI slave select / comparator 2 output
Pin 8 RE0/RD/AN5 — PORTE bit 0 / RD control / analog input AN5
Pin 9 RE1/WR/AN6 — PORTE bit 1 / WR control / analog input AN6
Pin 10 RE2/CS/AN7 — PORTE bit 2 / chip select / analog input AN7
Pin 11 VDD — Positive supply voltage (2.0 V to 5.5 V)
Pin 12 VSS — Ground reference
Pin 13 OSC1/CLKIN — Oscillator crystal input / external clock input
Pin 14 OSC2/CLKOUT — Oscillator crystal output / clock output
Pin 15 RC0/T1OSO/T13CKI — PORTC bit 0 / Timer1 oscillator output / Timer1/Timer3 clock input
Pin 16 RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 I/O
Pin 17 RC2/CCP1 — PORTC bit 2 / Enhanced CCP1 I/O
Pin 18 RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock
Pin 19 RD0/PSP0 — PORTD bit 0 / Parallel Slave Port data bit 0
Pin 20 RD1/PSP1 — PORTD bit 1 / Parallel Slave Port data bit 1
Pin 21 RD2/PSP2 — PORTD bit 2 / Parallel Slave Port data bit 2
Pin 22 RD3/PSP3 — PORTD bit 3 / Parallel Slave Port data bit 3
Pin 23 RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data
Pin 24 RC5/SDO — PORTC bit 5 / SPI data out
Pin 25 RC6/TX/CK — PORTC bit 6 / UART transmit / USB clock
Pin 26 RC7/RX/DT — PORTC bit 7 / UART receive / USB data
Pin 27 RD4/PSP4 — PORTD bit 4 / Parallel Slave Port data bit 4
Pin 28 RD5/PSP5 — PORTD bit 5 / Parallel Slave Port data bit 5
Pin 29 RD6/PSP6 — PORTD bit 6 / Parallel Slave Port data bit 6
Pin 30 RD7/PSP7 — PORTD bit 7 / Parallel Slave Port data bit 7
Pin 31 VSS — Ground reference (second VSS pin)
Pin 32 VDD — Positive supply voltage (second VDD pin)
Pin 33 RB0/INT0/FLT0 — PORTB bit 0 / external interrupt 0 / ECCP1 fault input
Pin 34 RB1/INT1 — PORTB bit 1 / external interrupt 1
Pin 35 RB2/INT2 — PORTB bit 2 / external interrupt 2
Pin 36 RB3/INT3/CCP2 — PORTB bit 3 / external interrupt 3 / CCP2 I/O
Pin 37 RB4/KBI0 — PORTB bit 4 / interrupt-on-change bit 0
Pin 38 RB5/KBI1 — PORTB bit 5 / interrupt-on-change bit 1
Pin 39 RB6/KBI2/PGC — PORTB bit 6 / interrupt-on-change bit 2 / ICSP clock
Pin 40 RB7/KBI3/PGD — PORTB bit 7 / interrupt-on-change bit 3 / ICSP data
Pin 41 NC — Not connected (per datasheet)
Pin 42 NC — Not connected (per datasheet)
Pin 43 NC — Not connected (per datasheet)
Pin 44 NC — Not connected (per datasheet)
Pin 45 EP — Exposed thermal pad - must be soldered to ground plane for thermal dissipation and electrical ground

Typical Applications

PIC18LF4523-I/ML is suitable for 6 applications: USB HID Peripherals, Industrial Control Panels, Home Appliances and White Goods, Automotive Interior Subsystems, Battery-Powered Data Loggers with USB, USB-to-Serial Bridge / CDC Dongle.

🧩

USB HID Peripherals

The PIC18LF4523-I/ML is a strong match for USB Human Interface Devices because its on-chip USB 2.0 Full-Speed SIE eliminates an external PHY and 3.3 V regulator, lowering BOM cost and PCB area in USB mice, keyboards, gamepads and custom HID controllers. With 32 KB FLASH, 1536 bytes SRAM and 36 digital I/O, the part can host the Microchip USB stack plus a HID report parser and a debounce/keyscan matrix in firmware without external memory. USB D+/D- trace matching within 150 mil and a 15 kV ESD array on the connector preserve USB-IF compliance.

🏭

Industrial Control Panels

The PIC18LF4523-I/ML fits industrial control panels thanks to its 13-channel 12-bit ADC for multi-sensor acquisition (4-20 mA, 0-10 V, RTD, thermocouple via op-amp front-end), two UART ports for Modbus RTU master/slave, plus a CCP/ECCP module for PWM-driven actuator control. The 2.0 V to 5.5 V wide-voltage range tolerates 24 V industrial rails when paired with a small switching pre-regulator. On-chip hardware multiplier and 10 MIPS throughput enable 32-bit arithmetic for filter math, PID loops and RMS calculations in motor-drive and process-control applications.

🏭

Home Appliances and White Goods

The PIC18LF4523-I/ML is well suited to washing machines, induction cookers, microwave ovens, HVAC and dishwasher controllers because of its 36 I/O pins (driving relays, triac interfaces, keypads, 7-segment LEDs and LCD modules) plus two analog comparators for zero-cross detection. The 32 KB FLASH comfortably fits state-machine firmware for wash cycles, induction PWM profiles and appliance safety interlocks; 256-byte EEPROM stores user settings (temperature, spin speed) across power cycles. The industrial -40 C to +85 C temperature grade handles appliance thermal stress near motors and heaters.

🚗

Automotive Interior Subsystems

The PIC18LF4523-I/ML suits automotive interior modules (instrument cluster back-end, HVAC controls, lighting, ambient LED drivers) thanks to its wide 2.0 V to 5.5 V operating range (allowing direct Li-ion or 12 V post-regulator operation), 36 I/O for segmented LCD/LED matrix and LIN/SCI-like UART for body-network gateways. The industrial temperature grade handles -40 C to +85 C cabin environments. Note that the PIC18LF4523-I/ML is NOT AEC-Q100 qualified; for AEC-Q100 automotive designs choose the PIC18F4523-I/PT-EQ automotive-grade variant or migrate to PIC18F46K22.

🔋

Battery-Powered Data Loggers with USB

The PIC18LF4523-I/ML is a good fit for USB-tethered portable data loggers and sensor pods thanks to its 2.0 V to 5.5 V range, which allows direct single-cell Li-ion (3.0-4.2 V) or 2xAA operation, and the on-chip USB SIE that lets the same port serve as both power source and data channel. nanoWatt Technology provides sleep currents under 1 uA with RTC and WDT running; the 13-channel 12-bit ADC handles temperature, humidity and pressure sensor arrays; 32 KB FLASH stores roughly 16 K samples of 2-byte data with timestamps before USB offload.

🌐

USB-to-Serial Bridge / CDC Dongle

The PIC18LF4523-I/ML is well matched to USB-to-UART/SPI/I2C bridge dongles because the on-chip USB SIE handles CDC class enumeration, while the two UARTs and one MSSP (SPI+I2C) expose two serial ports to the host PC. With 32 KB FLASH, the part easily fits Microchip's CDC + vendor-class composite stack plus a configuration EEPROM emulation in the 256-byte data EEPROM. The 44-QFN (8x8 mm) footprint keeps the dongle PCB under 20x30 mm, ideal for low-cost USB adapters.

Recommended Products Summary

PIC18LF4520-I/ML Microchip Technology Used in: USB HID Peripherals, USB-to-Serial Bridge / CDC Dongle MIC2026-2YM USB power switch with over-current protection Used in: USB HID Peripherals PIC18LF2523-I/ML Microchip Technology Used in: Industrial Control Panels, Battery-Powered Data Loggers with USB MCP2551-I/SN CAN transceiver companion for industrial field-bus Used in: Industrial Control Panels MCP23S17-E/SP 16-bit SPI I/O expander for keypad and LED matrix Used in: Home Appliances and White Goods PIC18LF2520-I/ML Microchip Technology Used in: Home Appliances and White Goods MCP2515-I/SO Standalone CAN controller for in-vehicle networking Used in: Automotive Interior Subsystems PIC18F46K22-I/PT AEC-Q100 grade, K22 family for harsher automotive thermal classes Used in: Automotive Interior Subsystems MCP9808T-E/MS High-accuracy I2C temperature sensor companion Used in: Battery-Powered Data Loggers with USB FT230XQ Alternative USB-UART bridge (not pin-compatible; different package) Used in: USB-to-Serial Bridge / CDC Dongle
What is the program memory size of the PIC18LF4523-I/ML?
The PIC18LF4523-I/ML integrates 32 KB (16K x 16 instructions) of self-programmable FLASH program memory, 1536 bytes of data SRAM and 256 bytes of data EEPROM. According to the Microchip datasheet (DS39609E), the FLASH supports ICSP (In-Circuit Serial Programming) and runtime self-programming, enabling bootloader-based field firmware updates. The 16K-word program space uses Microchip's 16-bit instruction word with an 8-bit data path (enhanced Harvard architecture).
What is the operating voltage range of the PIC18LF4523-I/ML?
The PIC18LF4523-I/ML operates from 2.0 V to 5.5 V, allowing direct connection to a single Li-ion cell, two AA cells, or a regulated 3.3 V / 5 V rail. The "LF" prefix indicates the wide-range low-voltage core; the standard "F" variants operate from 4.2 V to 5.5 V. Brown-out reset (BOR) is programmable with thresholds between 2.0 V and 4.2 V to ensure clean start-up and shut-down in low-voltage battery applications, per the Microchip PIC18F4523 datasheet.
Does the PIC18LF4523-I/ML have built-in USB?
Yes, the PIC18LF4523-I/ML integrates a full-speed USB 2.0 Serial Interface Engine (SIE) that supports Device, Host and OTG roles at up to 12 Mbps without an external PHY. The on-chip transceiver supports HID, CDC, vendor-class and mass-storage profiles, and the integrated 3.3 V USB voltage regulator eliminates most external circuitry. USB D+/D- pads are bonded to dedicated pins, requiring only 27 ohm series resistors and ESD protection.
What is the difference between PIC18LF4523 and PIC18LF4520?
The PIC18LF4523 adds an on-chip full-speed USB 2.0 transceiver/SIE and 256 bytes of data EEPROM compared to the PIC18LF4520. Both share 32 KB FLASH, 1536 bytes RAM, 36 I/O pins and the same 44-pin QFN (ML) footprint. So PIC18LF4523 is a drop-in upgrade for designs that need USB; PIC18LF4520 is preferred when USB is unused, saving silicon cost per the Microchip PIC18F4520/4523 datasheet.
How many ADC channels and timers does PIC18LF4523-I/ML have?
The PIC18LF4523-I/ML provides a 13-channel 12-bit Analog-to-Digital Converter with 100 ksps conversion rate, four timers (one 16-bit Timer1/Timer3 plus three 8-bit Timer0/Timer2/Timer4), two standard CCP modules and one enhanced ECCP (ECCP1) module for advanced PWM with dead-band control. This combination suits multi-sensor data acquisition and motor/lighting control, per the Microchip PIC18F4523 datasheet section 17.
Where can I buy PIC18LF4523-I/ML online?
The PIC18LF4523-I/ML is in stock at DigiKey (p/n 1228547-ND), Mouser (p/n 579-PIC18LF4523-I/ML), and is listed across 12 distributors on Octopart with bulk pricing down to roughly US$4.12 each at 2,500 pieces as of 2026-09-28. Lead time for factory reels is typically 8-12 weeks from Microchip; distributor stock usually ships same-day for quantities under 1,000 pieces.
What is the price of PIC18LF4523-I/ML in 100-piece quantity?
The PIC18LF4523-I/ML lists at approximately US$6.04 each in 100-piece quantities and US$6.78 each at qty 10, based on DigiKey and Mouser pricing indexed 2026-09-28. Octopart-reported third-party pricing ranges from US$2.76 to US$4.16 at higher volumes. Tier breaks are 1, 10, 100, 500, 1000, and 2500 pieces on distributor storefronts.
What is the lead time for PIC18LF4523-I/ML?
Distributor lead time for the PIC18LF4523-I/ML is typically same-day to 5 business days for quantities under 1000 pieces at DigiKey and Mouser (as of 2026-09-28). For 2,500-piece reels, distributor stock usually suffices; for 5,000+ piece builds, factory lead time is approximately 8-12 weeks. Third-party brokers may offer faster delivery but should be verified for authenticity and ESD handling compliance.
Is PIC18LF4523-I/ML in stock right now?
The PIC18LF4523-I/ML is currently reported as in stock at DigiKey and Mouser with several thousand units on hand, as of the 2026-09-28 pricing snapshot. Mouser Singapore also lists factory stock of the same ML package. Octopart aggregates 12 distributors and shows active offers across North America, Europe and Asia-Pacific, indicating healthy multi-source availability.
PIC18LF4523 vs PIC18LF4520 - which is better for USB applications?
The PIC18LF4523 is better for USB applications because it integrates a full-speed USB 2.0 SIE on-chip, whereas the PIC18LF4520 has no USB peripheral. Both share the same 44-pin QFN (ML) package and 32 KB FLASH, so the PIC18LF4523 can replace a PIC18LF4520 directly when USB is needed; conversely, choosing PIC18LF4520 saves BOM cost when USB is not required. For USB HID, CDC or mass-storage designs the PIC18LF4523 saves a US$1-2 external PHY.
When should I choose PIC18LF4523-I/ML over PIC18LF4520?
Choose the PIC18LF4523-I/ML whenever your design needs on-chip USB 2.0 full-speed (12 Mbps) Device, Host or OTG connectivity - HID peripherals, CDC serial bridges, mass storage and vendor-class devices - because the integrated SIE saves an external PHY and 3.3 V regulator. Choose PIC18LF4520 for the same 44-QFN footprint when USB is not used, since PIC18LF4520 has slightly lower unit cost and identical 32 KB FLASH, 1536-byte RAM and 36-I/O architecture.
What is the best drop-in replacement for PIC18LF4523-I/ML?
The best drop-in replacement for PIC18LF4523-I/ML is the same Microchip PIC18LF4523 in a different package code, such as PIC18LF4523-I/PT (44-TQFP) or PIC18LF4523T-I/ML (tape-and-reel variant). For feature-compatible pin-to-pin substitutes, PIC18LF4520-I/ML drops in directly but lacks USB; PIC18LF4523-I/P (40-DIP) shares the same silicon but changes the PCB footprint. Verify pinout per the Microchip datasheet before substituting.
Where to download PIC18LF4523-I/ML datasheet PDF?
The PIC18LF4523-I/ML datasheet (DS39609E or the current revision) can be downloaded from Microchip's official product page at microchip.com, or from the third-party mirror at abc-semi.com/datasheets/pic18lf4523-iml.pdf. The datasheet includes the pinout for the 44-QFN (ML) package, electrical characteristics, instruction set summary, peripheral driver libraries and reference C code for USB stack, ADC, PWM and ICSP. Always cross-check the latest revision letter on the manufacturer's website.
What is the pinout of PIC18LF4523-I/ML?
The PIC18LF4523-I/ML uses a 44-pin QFN (8x8 mm) package with exposed thermal pad. Pin 1 is located at the top-left with the dot marker; pin numbering follows counter-clockwise convention around the package. Key pins include VDD on pin 11 and pin 32, VSS on pin 12 and pin 31, MCLR/VPP on pin 1, OSC1/CLKIN on pin 13, OSC2/CLKOUT on pin 14, and the USB D+/D- pins on dedicated USB pads. The exposed pad (EP) is pin 45 and must be soldered to the ground plane per the Microchip datasheet pinout diagram.
What is the best NXP or ST equivalent for PIC18LF4523?
There is no direct NXP or ST cross-brand drop-in for the PIC18LF4523-I/ML because the QFN-44 (8x8) footprint, RISC instruction set and Microchip-specific peripherals (MSSP, ECCP, nanoWatt Technology) are unique to the PIC18 family. The closest cross-brand substitutes with USB 2.0 full-speed and similar 32 KB FLASH class are the NXP LPC1343 (32 KB FLASH, 44-pin QFN-like LQFP) and the STMicroelectronics STM32F070F4P6 (16 KB FLASH, TSSOP-20); however, neither is pin-compatible with the PIC18LF4523-I/ML QFN-44 footprint, so a PCB redesign is required. Verify with the Microchip cross-reference search tool before substituting.

Engineering reference data for PIC18LF4523-I/ML — comparison, design guidance, and compliance information.

Selection Guide

Choose the PIC18LF4523-I/ML when your embedded design needs on-chip USB 2.0 Full-Speed (12 Mbps) plus 32 KB FLASH, 1536 bytes of SRAM, 36 I/O pins and a 13-channel 12-bit ADC in a compact 44-QFN (8x8 mm) package running from 2.0 V to 5.5 V. This part is ideal for USB HID peripherals, CDC serial bridges, USB mass storage and industrial control panels. If you do not need USB but want the same QFN-44 footprint and FLASH/RAM density, downgrade to PIC18LF4520-I/ML for BOM savings. If you need only 16 KB FLASH (and same USB + QFN-44 footprint), choose PIC18LF2523-I/ML. For tape-and-reel packaging variants, choose PIC18LF4523T-I/ML which is silicon-identical. For a TQFP-44 package instead of QFN-44, choose PIC18LF4523-I/PT, but note that the land pattern differs. For AEC-Q100 automotive qualification, this part is NOT qualified - migrate to PIC18F46K22-I/PT or contact Microchip for an automotive-grade equivalent.

Comparison with Alternatives

Parameter This Product PIC18LF4523T-I/ML PIC18LF4520-I/ML PIC18LF2523-I/ML
Brand Microchip Technology Microchip Technology Microchip Technology Microchip Technology
Package 44-QFN (8x8 mm) - ML 44-QFN (8x8 mm) - ML (same) 44-QFN (8x8 mm) - ML (same) 44-QFN (8x8 mm) - ML (same)
Program FLASH 32 KB (16K x 16) 32 KB 32 KB 16 KB (-50%)
Data SRAM 1536 bytes 1536 bytes 1536 bytes 1536 bytes
Data EEPROM 256 bytes 256 bytes 0 bytes 256 bytes
USB 2.0 Full-Speed SIE Yes (on-chip) Yes No Yes
CPU Frequency 40 MHz (10 MIPS) 40 MHz (10 MIPS) 40 MHz (10 MIPS) 40 MHz (10 MIPS)
I/O Pins 36 36 36 36
Operating Voltage 2.0 V to 5.5 V 2.0 V to 5.5 V 2.0 V to 5.5 V 2.0 V to 5.5 V

Key Differentiators

  • On-chip USB 2.0 Full-Speed SIE eliminates external PHY (vs PIC18LF4520-I/ML)
  • Highest-density same-footprint FLASH in PIC18F452x family (vs PIC18LF2523-I/ML)
  • Industrial temperature grade (-40 C to +85 C) for harsh environments (vs PIC18F4523-I/PT (standard temp grade))

Design Notes

The 44-QFN (ML) package has an exposed thermal pad (EP, pin 45) that MUST be soldered to a continuous ground plane with at least 4 thermal vias (9-mil hole, 12-mil annular ring) for proper heat dissipation and electrical grounding. Skip-via the EP plane to maintain ground continuity. Place a 100 nF X7R 0402 decoupling capacitor within 3 mm of each VDD pin (pin 11 and pin 32), and a single 4.7 uF X5R bulk capacitor adjacent to the package. Microchip recommends keeping the EP plane at least 50% coverage of the package footprint for thermal performance up to 1 W dissipation.

Route USB D+ (RC4) and D- (RC5) as a length-matched differential pair within 150 mil tolerance, with 90-ohm differential impedance and a continuous ground reference plane beneath. Add a 27-ohm series resistor on each line near the MCU side, and place the USB connector ESD protection array (such as USBLC6-2SC6) within 3 mm of the connector body. Keep D+/D- traces away from PWM switching nodes such as ECCP1 (RC2) and Timer1 oscillator pins (RC0/RC1) to preserve USB signal integrity and pass USB-IF compliance testing.

When powering the PIC18LF4523-I/ML from a noisy 5 V rail (such as a USB VBUS that may carry switching noise), add a ferrite bead (600 ohm at 100 MHz, 0402 size) plus a 10 uF tantalum bulk capacitor between VBUS and the VDD pins. Enable the BOR (Brown-Out Reset) with a threshold 0.2 V below the minimum operating VDD (e.g. 2.0 V) to ensure clean start-up and prevent FLASH corruption during brown-out events. nanoWatt Technology can drop quiescent current under 1 uA in sleep mode with RTCC and WDT running, per the Microchip datasheet power-management section.

Compliance Information

RoHS
Compliant
REACH
Compliant
AEC-Q100
Not Qualified
Lead Free
Yes
Halogen Free
Yes
Conflict Minerals
Compliant

RoHS and REACH compliance per Microchip product page (as of 2026-09-28). This part is NOT AEC-Q100 qualified; for automotive designs migrate to PIC18F46K22-I/PT or contact Microchip for an AEC-Q100 grade. Lead-free and halogen-free per Microchip material declaration.

Data verified on: 2026-09-28 — data verified and curated by XAIPART's component engineering team

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