PIC18LC242T-I/SO - 8-bit PIC MCU, 16KB OTP, 40MHz | Microchip
MPN: PIC18LC242T-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.4 | $8.40 |
| 10 | $7.62 | $76.20 |
| 100 | $6.85 | $685.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.42 | $5,420.00 |
PIC18LC242T-I/SO Overview
An 8-bit PIC microcontroller is a Harvard-architecture RISC device where program and data memories are accessed via separate buses, enabling single-cycle instruction execution. The OTP variant ships factory-programmed and is intended for low-to-mid volume production where firmware does not need post-shipment updates. The PIC18C family extends the original PIC16 instruction set with 16-bit instructions, an 8-bit data path, and a hardware 8x8 single-cycle multiplier, placing it in the broader Microchip MCU taxonomy above baseline PIC16 parts and below the flash-based PIC18F and PIC18K families.
Key features include 22 I/O pins (23 on related datasheet variants), an external oscillator interface that supports 4-10 MHz crystals with PLL active or a 40 MHz external clock, 8-level interrupt priority, and an analog/digital peripheral set that includes capture/compare/PWM modules, a 10-bit ADC, and an MSSP (Master Synchronous Serial Port) for I2C/SPI. Power-fail detection and a programmable brown-out reset (BOR) circuit protect against unstable supply transitions during 4.0V-5.5V operation.
The architecture separates instruction fetch (16-bit) from operand access (8-bit), letting the CPU sustain 10 MIPS throughput at 40 MHz while keeping peripheral and interrupt latency deterministic. Internal oscillator calibration, dual analog comparators, and sleep/idle modes balance compute performance against the low-power envelope needed in industrial and embedded designs.
Typical applications include industrial control loops, automotive body and chassis subsystems (the LC supply range supports 3.0V-5.5V battery-backed operation), consumer white goods, HVAC controls, and power-conversion front-ends where the MSSP drives a digital PFC stage. The wide-body SOIC footprint suits hand-repair and through-hole-compatible assembly lines that prefer surface-mount packages with strong mechanical leads.
Designers should note the LC suffix indicates a low-voltage core (3.0V-5.5V), not the 5.0V-5.5V F variant; mismatching the supply rail is a common bring-up fault. The MSSP module has documented anomalies on certain revisions - engineers should review Microchip silicon errata before locking the firmware design.
This page synthesizes distributor pricing, tape-and-reel packaging options, drop-in alternatives within the PIC18 family, and practical PCB-layout notes not present in the Microchip datasheet.
Drop-in alternatives for PIC18LC242T-I/SO — 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 PIC18LC242T-I/SO (same form factor and footprint) — differing in Mounting Type, Program Memory Size, Program Memory Type, ADC, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18LC242-I/SO
✅ Drop-In✓ In Stock
$2.75 / Unit
View Datasheet →PIC18F2480T-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LC252T-I/SO
✅ Drop-In✓ In Stock
$4.05 / Unit
View Datasheet →PIC18LF2685-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LC242T-I/SO Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit RISC |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 16 KB (8K x 16) |
| RAM Size | 512 x 8 bytes |
| EEPROM Size | Not present (OTP device) |
| Instruction Width | 16-bit instructions, 8-bit data path |
| Maximum Clock Frequency | 40 MHz (10 MIPS) |
| Oscillator Type | External (4-10 MHz with PLL, up to 40 MHz direct) |
| Supply Voltage (VDD) | 3.0 V to 5.5 V (LC suffix) |
| Number of I/O Pins | 22 |
| Interrupt Priority Levels | 8 |
| Hardware Multiplier | Single-cycle 8 x 8 |
| ADC | 10-bit (peripherals vary by speed grade) |
| Package / Case | 28-SOIC (0.295 inch / 7.50 mm width) |
| Mounting Type | Surface Mount (SOIC wide-body) |
| Operating Temperature Range | -40 C to +85 C (Industrial grade) |
| MSL Level | 1 (per JEDEC J-STD-020, typical for OTP SOIC) |
| Lead Finish | Matte Tin (Pb-free, per Microchip ordering code suffix) |
| RoHS Status | Compliant |
PIC18LC242T-I/SO Pin Configuration
| Pin 1 | MCLR/VPP — Master clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / analog input 2 / VREF- |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input 3 / VREF+ |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/CLKIN — Oscillator crystal input / external clock in |
| Pin 10 | OSC2/CLKOUT — Oscillator crystal output / clock out (FOSC/4) |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 output / clock in |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 input / Capture-Compare-PWM2 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / Capture-Compare-PWM1 |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / UART TX / synchronous clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / UART RX / synchronous data |
| Pin 19 | VSS — Ground reference (second VSS pin) |
| Pin 20 | VDD — Positive supply voltage |
| Pin 21 | RB0/INT0 — PORTB bit 0 / external interrupt 0 |
| Pin 22 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 23 | RB2/INT2 — PORTB bit 2 / external interrupt 2 |
| Pin 24 | RB3/INT3/CCP2 — PORTB bit 3 / external interrupt 3 / CCP2 alt |
| Pin 25 | RB4 — PORTB bit 4 |
| Pin 26 | RB5 — PORTB bit 5 |
| Pin 27 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 28 | RB7/PGD — PORTB bit 7 / ICSP data |
Typical Applications
PIC18LC242T-I/SO is suitable for 6 applications: Industrial Sensor Hub, Appliance Control Board, Automotive Body Module, HVAC Damper Actuator, Smart Meter Display Driver, Power Supply PFC Front-End.
Industrial Sensor Hub
The PIC18LC242T-I/SO suits always-powered industrial sensor-hub designs where firmware is locked at production and BOM cost dominates. Its 16 KB OTP holds typical sensor-fusion state machines, the 22 I/O pins drive 4-20 mA loop inputs plus relay outputs, and the 3.0 V-5.5 V supply range operates directly from a 24 V industrial bus stepped down by a small DC-DC converter. The 8-level interrupt priority handles time-critical limit-switch events without jitter. Designers should plan for an external RS-485 transceiver because the MCU's MSSP cannot drive a differential bus directly.
Recommended
Appliance Control Board
In washing-machine, dishwasher, and microwave control boards the PIC18LC242T-I/SO drives triac outputs for heater banks and AC motor relays through opto-isolated I/O. The 16 KB OTP absorbs PID-loop plus timer-state code, while the 10-bit ADC reads thermistor and water-level sensors. Operating from 5 V through an onboard rectifier, the part consumes tens of mA - sufficient headroom for optocoupler LED drive without extra buffers. OTP memory prevents post-shipping field reprogramming, an anti-tamper benefit for safety-critical appliance firmware.
Recommended
Automotive Body Module
Within non-safety automotive body controllers - window lifts, seat adjusters, lighting drivers - the PIC18LC242T-I/SO handles 8-bit logic without the AEC-Q100 cost premium of K-series parts. The MCU operates from a regulated 5 V body bus, and its 22 I/O pins multiplex with LIN-slave transceivers over UART. Designers must add TVS diodes and reverse-battery protection on VDD; the MCU itself has no integrated automotive load-dump resilience. For safety-critical modules, switch to AEC-Q100-qualified PIC18F K-series parts in the same 28-SOIC footprint.
Recommended
HVAC Damper Actuator
Damper-actuator controllers in variable-air-volume HVAC systems use the PIC18LC242T-I/SO as a position-loop controller driving a brushless DC motor through external MOSFETs. The 8-bit PIC18 core executes a PID loop every 10 ms using the 40 MHz clock, while the 10-bit ADC reads the feedback potentiometer for shaft position. OTP memory locks the loop tuning per damper model, reducing field-tampering risk. Industrial-grade -40 C to +85 C operation tolerates rooftop and plenum mounting.
Recommended
Smart Meter Display Driver
Gas and water meter displays use the PIC18LC242T-I/SO as a low-power LCD-segment driver subcontroller, reading the meter's primary measurement ASIC over SPI and refreshing a multi-digit LCD. The 8-bit core handles anti-tamper logging in OTP, and 3.0 V supply tolerance suits battery-backed designs. Because OTP cannot be flashed in the field, end customers cannot modify tariff schedules - a regulatory requirement in some regional metering standards.
Recommended
Power Supply PFC Front-End
Digitally-controlled PFC (Power Factor Correction) front-ends for offline LED drivers and appliance SMPS use the PIC18LC242T-I/SO as a low-cost peak-current-mode controller. The MSSP drives an external PFC gate-driver such as the NCP1339 over SPI, the 10-bit ADC samples rectified mains for zero-cross detection, and the 8-bit core computes the duty cycle at 40 MHz. OTP locks the firmware against end-user modification. For DFP/CCM control loops requiring finer resolution, consider the dsPIC33 family in a larger package.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LC242T-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18LC242-I/SO | PIC18F2480T-I/SO | PIC18LC252T-I/SO | PIC18LF2685-I/SO |
|---|---|---|---|---|---|
| Package | 28-SOIC (0.295 inch / 7.50 mm) | 28-SOIC (0.295 inch / 7.50 mm) - same | 28-SOIC (0.295 inch / 7.50 mm) - same | 28-SOIC (0.295 inch / 7.50 mm) - same | 28-SOIC (0.295 inch / 7.50 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 16 KB OTP | 16 KB OTP (identical) | 16 KB Flash (same density, erasable) | 32 KB OTP (+100%) | 96 KB Flash (+500%) |
| Memory Type | OTP | OTP (same) | Flash (updatable) | OTP (same) | Flash (updatable) |
| Maximum Clock | 40 MHz (10 MIPS) | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Supply Voltage | 3.0 V to 5.5 V | 3.0 V to 5.5 V (same) | 4.0 V to 5.5 V (F variant) | 3.0 V to 5.5 V (LC) | 2.0 V to 3.6 V (LF) |
| CAN Interface | No | No | Optional on die | No | Yes (CAN 2.0B) |
| MSSP Peripheral | Yes (I2C/SPI) | Yes | Yes | Yes | Yes + 2nd MSSP |
| Operating Temperature | -40 C to +85 C (Industrial) | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| Packaging Format | Tape & Reel (T suffix) | Tube (no T) | Tape & Reel | Tape & Reel | Tube (no T) |
Key Differentiators
- Low-voltage LC variant supports 3.0 V to 5.5 V (broader than the F variant's 5.0 V minimum) (vs PIC18F2480T-I/SO)
- Same-die tape-and-reel packaging for fully-automated SMD assembly (vs PIC18LC242-I/SO)
- Lower BOM cost than flash PIC18F family with same PIC18 instruction-set compatibility (vs PIC18LF2685-I/SO)
Design Notes
Place a 100 nF ceramic decoupling capacitor within 5 mm of pins 8 (VSS) and 20 (VDD). Add a 10 uF bulk tantalum or low-ESR aluminum capacitor on the same VDD trace, rated at least twice VDD max. Brown-out reset (BOR) holds the MCU in reset until VDD reaches a stable threshold above 2.7 V; enable BOR in configuration registers to prevent code execution with a partially ramped supply. Estimated: at 40 MHz and 5.0 V VDD, the LC242 draws approximately 25-40 mA total current. Do not share MCU VDD with high-current inductive loads.
Route the crystal traces (OSC1/OSC2, pins 9 and 10) on the top layer only, surrounded by a ground guard ring, with trace length below 10 mm to minimize stray capacitance. Place MCLR (pin 1) with a 10 kohm pullup resistor and a 100 nF capacitor to ground for a clean power-on reset - this is the most common bring-up fault on PIC18 designs. Keep analog traces (RA0-RA5) separated from digital switching lines by a ground pour or at least 3 mm spacing to avoid ADC noise injection.
Do not mistake the LC suffix for a 5V-only part - the LC variant operates 3.0 V to 5.5 V, and substituting an F (5.0V-only) part on a 3.3V rail will halt operation. The MSSP module has documented silicon errata (PIC18C242 MSSP anomaly) on certain silicon revisions per Microchip read-me documents; check the silicon errata before locking the firmware design. OTP memory cannot be reprogrammed - mis-programmed OTPs must be physically replaced. Always prototype with a flash PIC18F2480T-I/SO in the same socket before committing to OTP for production.
When using ICSP (in-circuit serial programming) on production boards, isolate RB6 (PGC, pin 27) and RB7 (PGD, pin 28) from external pull-ups stronger than 10 kohm, otherwise ICSP communication may fail. Add 4.7 kohm series resistors on PGC/PGD lines if your application uses heavy capacitive loading on those pins. Do not use the debugger on pin 1 (MCLR/VPP) with less than 0.5 V margin during programming - VPP can reach 13V on Microchip programmers.
Compliance Information
RoHS compliant per Microchip product page declaration, Pb-free matte-tin lead finish. AEC-Q100 not applicable - OTP PIC18C family is not automotive-qualified; for AEC-Q100 designs use PIC18F K-series or dsPIC33. REACH SVHC compliance confirmed via Microchip environmental certification page.
