PIC18LC242-I/SO - 8-Bit 40MHz 16KB OTP MCU | Microchip
MPN: PIC18LC242-I/SO ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.4 | $4.40 |
| 10 | $4.07 | $40.70 |
| 100 | $3.5 | $350.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $2.75 | $2,750.00 |
PIC18LC242-I/SO Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, program memory, RAM, and peripheral set. The PIC18 family represents Microchip's high-performance 8-bit tier, sitting above baseline PIC16 parts in instruction set richness and peripheral count. PIC18LC variants are the low-voltage (2.0 V to 5.5 V) siblings of the PIC18F flash parts, offering OTP programmability for cost-sensitive production. The LC sub-family is positioned between baseline PIC16 and higher-pin-count PIC18F parts in Microchip's 8-bit hierarchy: PIC16 -> PIC18LC (OTP, low-voltage) -> PIC18F (flash) -> PIC18F J/K-series (high-performance).
Key features include 512 bytes of data RAM, 22 digital I/O lines, an integrated 10-bit A/D converter with multiple channels, a USART module for asynchronous serial communication, MSSP for SPI/I2C, Capture/Compare/PWM modules, and support for external oscillator operation up to 40 MHz (or 4 to 10 MHz with PLL). The -I suffix denotes the industrial temperature range of -40 C to +85 C.
The PIC18LC242 uses a RISC-style Harvard architecture with 16-bit wide instructions and an 8-bit data path. The OTP (One-Time Programmable) program memory makes it ideal for high-volume production where firmware is finalized and reprogramming is not required, lowering per-unit cost compared with flash-based PIC18F equivalents. The 28-SOIC package provides a 7.50 mm body width suitable for through-hole-style PCB prototyping or surface-mount production.
Typical applications include industrial control loops, motor control interfaces, sensor signal conditioning, low-cost embedded control nodes, and consumer appliance control. Its compact 28-pin footprint, A/D converter, and PWM outputs also suit HVAC damper/valve actuation and small appliance user-interface boards.
When designing with this part, note that Microchip recommends the flash-based PIC18F242 as the recommended new design replacement for the PIC18LC242 family. Engineers should plan firmware migration paths if field upgrades or design-for-test flexibility are required.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found on any single manufacturer or distributor page.
Drop-in alternatives for PIC18LC242-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 PIC18LC242-I/SO (same form factor and footprint) — differing in ADC, Package, Operating Temperature, Core, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F242-I/SO
✅ Drop-In✓ In Stock
$3.5 / Unit
View Datasheet →PIC18C242-I/SO
✅ Drop-In✓ In Stock
$3.2 / Unit
View Datasheet →PIC18F252-I/SO
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →PIC18F442-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18LF242-I/SO
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC16F877A-I/SO
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18LC242-I/SO Maximum Ratings & Electrical Characteristics
| Product Family | PIC18C |
| Core Architecture | 8-bit PIC enhanced RISC |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 16 KB (8K x 16) |
| Data RAM | 512 bytes |
| Maximum CPU Frequency | 40 MHz |
| Performance | 10 MIPS (100 ns instruction cycle) |
| Supply Voltage Range | 2.0 V to 5.5 V (LC low-voltage variant) |
| I/O Pins | 22 (per DigiKey listing) or 23 (per Mouser listing) |
| A/D Converter | 10-bit, multi-channel |
| Communication Modules | USART, MSSP (SPI/I2C) |
| PWM Modules | Capture/Compare/PWM (CCP) |
| Oscillator Support | External, 4-10 MHz with PLL |
| Instruction Set | 77 single-word instructions |
| Operating Temperature | -40 C to +85 C (industrial, -I suffix) |
| Package | 28-SOIC (7.50 mm width) |
| Mounting Type | Surface Mount |
| Packaging | Tube |
| RoHS Status | Compliant |
| Recommended Replacement | PIC18F242 (flash-based equivalent per Microchip datasheet) |
PIC18LC242-I/SO Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0 — PORTA bit 0 / A/D channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / A/D channel 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / A/D channel 2 / A/D negative reference |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / A/D channel 3 / A/D positive reference |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / A/D channel 4 / SPI slave select |
| Pin 8 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| Pin 9 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 10 | RC0/T1OSI — PORTC bit 0 / Timer1 oscillator input |
| Pin 11 | RC1/T1OSI — PORTC bit 1 / Timer1 oscillator output |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM1 |
| Pin 13 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 17 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 18 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port bit 0 |
| Pin 19 | RD1/PSP1 — PORTD bit 1 / Parallel Slave Port bit 1 |
| Pin 20 | RD2/PSP2 — PORTD bit 2 / Parallel Slave Port bit 2 |
| Pin 21 | RD3/PSP3 — PORTD bit 3 / Parallel Slave Port bit 3 |
| Pin 22 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port bit 4 |
| Pin 23 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port bit 5 |
| Pin 24 | RD6/PSP6 — PORTD bit 6 / Parallel Slave Port bit 6 |
| Pin 25 | RD7/PSP7 — PORTD bit 7 / Parallel Slave Port bit 7 |
| Pin 26 | RE0/RD/AN5 — PORTE bit 0 / read control / A/D channel 5 |
| Pin 27 | RE1/WR/AN6 — PORTE bit 1 / write control / A/D channel 6 |
| Pin 28 | VSS — Ground reference |
Typical Applications
PIC18LC242-I/SO is suitable for 6 applications: Industrial Sensor Interface Board, Small Appliance Control Board, HVAC Damper and Valve Actuator, Battery-Powered Telemetry Node, Automotive Interior Lighting Controller, Consumer Electronics User Interface Board.
Industrial Sensor Interface Board
The PIC18LC242-I/SO's 10-bit A/D converter and 22-23 digital I/O pins make it a strong fit for industrial sensor interface boards where analog transducers (temperature, pressure, flow) must be digitized and reported over a serial link. Operating from 2.0 V to 5.5 V, it accepts 3.3 V or 5 V sensor rails directly without level shifting, while the 40 MHz core runs calibration and linearization routines within tight control-loop budgets. The USART connects to RS-232/RS-485 transceivers for SCADA or fieldbus reporting, and the CCP modules drive PWM outputs for actuator trim. Industrial-temperature -40 C to +85 C rating supports factory-floor and outdoor-enclosure deployment.
Recommended
Small Appliance Control Board
Cost-sensitive small appliance designs (coffee makers, washing machines, dishwashers, microwave ovens) benefit from the PIC18LC242-I/SO's low per-unit cost at high volume, OTP program memory that locks firmware at production, and integration of PWM, A/D, and GPIO in a compact 28-SOIC footprint. The 10 MIPS performance handles user-interface scanning, motor-driver PWM, and sensor feedback loops simultaneously. Industrial temperature grade tolerates the elevated ambient inside appliance housings, while the 2.0-5.5 V supply range simplifies power supply design from rectified 3.3 V or 5 V rails.
Recommended
HVAC Damper and Valve Actuator
Building automation damper and valve actuators require the PIC18LC242-I/SO's combination of 10-bit A/D for position feedback, CCP/PWM outputs for motor speed/direction control, and USART for BACnet/Modbus fieldbus communication. The 40 MHz core runs PID control loops at sub-millisecond update rates while servicing the communication stack. Industrial temperature grade handles equipment-room and rooftop-unit environments, and the 28-SOIC package's 7.50 mm width fits inside compact actuator housings. OTP memory prevents unauthorized recalibration in the field.
Recommended
Battery-Powered Telemetry Node
Low-power remote telemetry nodes (environmental monitors, asset trackers, irrigation controllers) use the PIC18LC242-I/SO's 2.0 V to 5.5 V supply range to operate directly from a 3.6 V lithium primary cell or two AA alkaline cells without a boost converter. The PIC18 core's SLEEP/idle modes combined with the part's modest 40 MHz peak draw allow duty-cycled wake-sleep telemetry cycles that extend battery life. The 10-bit A/D digitizes battery voltage and sensor inputs, while the USART drives a low-power radio module for periodic uplink transmissions.
Recommended
Automotive Interior Lighting Controller
Ambient and courtesy lighting modules inside automotive cabins (footwell LEDs, door-handle illumination, instrument-cluster backlight dimming) leverage the PIC18LC242-I/SO's PWM channels for smooth brightness control, A/D for ambient-light sensor input, and 28-SOIC compact footprint for module integration behind trim panels. Industrial temperature rating covers cabin environments, while the 5 V tolerance interfaces directly with body-control modules. Note: for under-hood or safety-critical automotive applications, Microchip recommends AEC-Q100-qualified PIC18F-K or PIC18F-J variants instead.
Recommended
Consumer Electronics User Interface Board
User-interface boards in consumer electronics (set-top box front panels, audio equipment displays, smart-home control panels) use the PIC18LC242-I/SO to scan keypads, drive LED or character-LCD displays, and handle IR remote-control decoding via the CCP/capture modules. The 16 KB OTP memory stores menu state machines and IR code libraries, while the 22-23 I/O pins interface directly to matrix keypads, rotary encoders, and LED drivers. The 28-SOIC package drops onto standard surface-mount assembly lines alongside other consumer-product ICs.
Recommended
Recommended Products Summary
Engineering reference data for PIC18LC242-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F242-I/SO | PIC18C242-I/SO | PIC18F252-I/SO | PIC18F442-I/SO | PIC18LF242-I/SO | PIC16F877A-I/SO |
|---|---|---|---|---|---|---|---|
| Package | 28-SOIC (7.50mm) | 28-SOIC (7.50mm) - same | 28-SOIC (7.50mm) - same | 28-SOIC (7.50mm) - same | 28-SOIC (7.50mm) - same | 28-SOIC (7.50mm) - same | 28-SOIC (7.50mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | 16KB OTP | 16KB Flash | 16KB OTP | 32KB Flash | 16KB Flash | 16KB Flash | 14KB Flash |
| Data RAM | 512 bytes | 512 bytes | 512 bytes | 1.5 KB | 4 KB | 512 bytes | 368 bytes |
| Maximum Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 20 MHz |
| Supply Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 4.2 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 3.6 V | 2.0 V to 5.5 V |
| I/O Pins | 22-23 | 23 | 22-23 | 23 | 34 | 23 | 22 |
| A/D Converter | 10-bit, multi-channel | 10-bit, 5 channels | 10-bit, multi-channel | 10-bit, 5 channels | 10-bit, 8 channels | 10-bit, 5 channels | 10-bit, 8 channels |
| Reprogrammability | No (OTP) | Yes (Flash, ICSP) | No (OTP) | Yes (Flash, ICSP) | Yes (Flash, ICSP) | Yes (Flash, ICSP) | Yes (Flash, ICSP) |
Key Differentiators
- Cost-optimized OTP memory for high-volume locked-firmware production (vs PIC18F242-I/SO)
- PIC18C242/252/442/452 family pin-compatible with newer PIC18F variants (vs PIC16F877A-I/SO)
- Recommended replacement path is documented and same-package (vs PIC18F252-I/SO)
- Same-family low-voltage LF variant available for battery applications (vs PIC18LF242-I/SO)
Design Notes
The PIC18LC242-I/SO operates across 2.0 V to 5.5 V but the LC sub-family is optimized for low-voltage battery applications. Decouple VDD with a 100 nF ceramic plus 10 uF bulk capacitor within 25 mm of the VDD pin to suppress switching transients from internal core activity. AVDD (if separate on the part variant) requires its own 100 nF decoupling for A/D converter reference stability. For battery-powered designs, leverage the PIC18 SLEEP/idle modes - wake on Watchdog Timer or external interrupt to drop average current below 1 uA.
Route the OSC1/OSC2 crystal traces as short, symmetric loops with guard ground to minimize stray capacitance. Place the crystal within 5 mm of the OSC pins and keep digital signal traces (PWM, USART) at least 3 mm away to avoid coupling noise into the oscillator. MCLR requires a 10 kohm pull-up to VDD; if in-circuit serial programming (ICSP) is desired, route the PGD/PGC lines to an ICSP header with no series resistance. The 28-SOIC land pattern should follow IPC-7351 nominal-density guidelines with 1.27 mm pitch.
Do not assume the PIC18LC242-I/SO can be reprogrammed in the field - the OTP memory locks firmware at the first programming cycle, so any firmware bug requires a new OTP part for production. Always prototype with the flash-based PIC18F242-I/SO first and migrate to the LC OTP only after firmware is finalized. The CCP module in Compare toggle mode (CCPxCON = b00xx0010) has documented errata that may cause unexpected pin operation per Microchip datasheet errata - review the silicon errata before selecting this mode. For 3.3 V system designs, verify VOH min of PORTC/PORTD exceeds your load's VIH min under all temperature corners.
When using the USART at high baud rates (>115200) with long PCB traces, place a 100 ohm series termination at the MCU TX pin to dampen reflections. For I2C bus via RC3/RC4 (SCL/SDA), use 4.7 kohm pull-ups to VDD for standard-mode (100 kHz) or 2.2 kohm for fast-mode (400 kHz); PIC18 open-drain outputs cannot drive the bus without external pull-ups. The A/D converter achieves specified accuracy only with a quiet VREF+ - if VREF+ shares a rail with a switching regulator, add a ferrite bead and 10 uF + 100 nF RC filter to isolate A/D reference noise from digital switching noise.
Compliance Information
RoHS compliant per Microchip product page and DigiKey listing. Not AEC-Q100 qualified - for automotive applications choose AEC-Q100-qualified PIC18F-K or PIC18F-J variants instead. Conflict minerals statement per Microchip's published CMRT.
