PIC18F242T-I/SO - 40MHz 8-bit MCU, 16KB Flash, 28-SOIC | Microchip
MPN: PIC18F242T-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.48 | $7.48 |
| 10 | $6.72 | $67.20 |
| 100 | $5.95 | $595.00 |
| 500 | $5.21 | $2,605.00 |
| 1,000 | $4.65 | $4,650.00 |
PIC18F242T-I/SO Overview
A PIC18F-series 8-bit microcontroller is a single-chip computer based on Microchip's enhanced PIC RISC architecture. The PIC18F family sits at the top of Microchip's 8-bit portfolio, above PIC10/12/16 families and below the 16-bit PIC24/dsPIC33 families. Within the broader taxonomy it belongs to the microcontrollers product category, which itself is a subset of integrated circuits / embedded processors. PIC18F parts are widely used in cost-sensitive, deterministic real-time control where the simplicity of an 8-bit core outweighs the throughput of an ARM Cortex-M device.
Key features of this part include 16 KB self-programmable FLASH, hardware USART, MSSP (SPI/I2C), CCP/PWM modules, an enhanced 10-bit ADC, and four oscillator options including the internal 8 MHz RC oscillator. The nanoWatt technology provides dynamic and sleep-mode current management enabling battery-friendly designs. The PIC18F242T-I/SO is fully upward source-code compatible with PIC16C5X, PIC12CXXX, PIC16CXX and PIC17CXX devices, easing migration from older designs.
The architecture is a 16-bit instruction word with an 8-bit data path and 31-level hardware stack, supporting linear memory addressing and C-compiler-friendly programming. Instruction execution is single-cycle at 40 MHz (10 MIPS), providing deterministic interrupt latency for closed-loop control loops such as motor commutation and power-conversion feedback.
Typical applications include industrial sensor conditioning, small motor control (BLDC stepper drivers), USB-to-UART bridging using the on-chip USART, battery chargers with CC/CV profiling, and embedded human-machine interfaces (HMI) with character LCDs and keypads. The wide operating voltage (4.2V-5.5V) and 25 I/O count strike a balance between analog signal availability and digital fan-out.
When designing with this part, ensure decoupling capacitors are placed within 5 mm of VDD/AVDD with a 100 nF + 10 uF combination, and that the MCLR pin is pulled to VDD through a 10 kohm resistor with a 100 nF cap for in-circuit debugging. For low-power designs, leverage the nanoWatt sleep modes rather than relying on clock slowdown alone.
This page consolidates current distributor pricing, drop-in same-package alternatives, and practical engineering notes that the manufacturer datasheet does not directly provide, giving purchasing and design teams a single decision-ready reference.
Drop-in alternatives for PIC18F242T-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 PIC18F242T-I/SO (same form factor and footprint) — differing in Package, ADC, Core Architecture, Operating Temperature, Program Memory (Flash).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F242-I/SO
✅ Drop-In✓ In Stock
$3.5 / Unit
View Datasheet →PIC18F252T-I/SO
✅ Drop-In✓ In Stock
$6.91 / Unit
View Datasheet →PIC18F2420T-I/SO
✅ Drop-In✓ In Stock
$3.5 / Unit
View Datasheet →PIC18F23K22T-I/SO
✅ Drop-In✓ In Stock
$1.34 / Unit
View Datasheet →PIC18F2520T-I/SO
✅ Drop-In✓ In Stock
$4.62 / Unit
View Datasheet →PIC18F258T-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F242T-I/SO Maximum Ratings & Electrical Characteristics
| Product Family | PIC18F |
| Core Architecture | PIC 8-bit (16-bit instruction word) |
| Instruction Set | 77 single-word instructions |
| Maximum CPU Frequency | 40 MHz |
| Performance | 10 MIPS (100 ns instruction execution) |
| Program Memory (FLASH) | 16 KB (8K x 16) |
| RAM | 768 bytes |
| EEPROM | 256 bytes |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| I/O Pins | 25 |
| ADC | 10-bit, up to 5 channels |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package | 28-pin SOIC (SO) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (T) |
| Oscillator Options | XT, HS, RC, Internal 8 MHz RC |
| Power-Saving Modes | nanoWatt (sleep, idle, run) |
| RoHS Status | Compliant |
PIC18F242T-I/SO Pin Configuration
| Pin 1 | MCLR/VPP/RA5 — Master Clear (reset) / Programming voltage / RA5 |
| 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/CLKI/RA7 — Crystal oscillator input / External clock input / RA7 |
| Pin 10 | OSC2/CLKO/RA6 — Crystal oscillator output / Clock output / RA6 |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 output |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| 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 / USART TX / USART clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 19 | VSS — Ground reference |
| 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/CCP2 — PORTB bit 3 / CCP2 output |
| Pin 25 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 26 | RB5 — PORTB bit 5 (interrupt-on-change) |
| Pin 27 | RB6/PGC — PORTB bit 6 / ICSP clock (interrupt-on-change) |
| Pin 28 | RB7/PGD — PORTB bit 7 / ICSP data (interrupt-on-change) |
Typical Applications
PIC18F242T-I/SO is suitable for 6 applications: Industrial Sensor Conditioning, Small BLDC / Stepper Motor Control, USB-to-UART Bridge / Serial Converter, Battery Chargers with CC/CV Profiling, Embedded HMI with Character LCD & Keypad, Automotive Body Electronics (Non-Safety).
Industrial Sensor Conditioning
The PIC18F242T-I/SO fits industrial sensor signal conditioning boards because its 10-bit ADC with up to 5 analog inputs supports thermocouple, RTD bridge amplification, and 4-20 mA loop readout, while the 25 I/O lines drive status LEDs and opto-isolated digital outputs. The 4.2V-5.5V supply matches 24V industrial rails after buck regulation, and -40C to +85C operation covers factory-floor environments. At 40 MHz/10 MIPS the device runs deterministic oversampling and digital filtering to improve effective ADC resolution beyond the native 10 bits for pressure and load-cell conditioning. The nanoWatt sleep currents allow battery-backed sensor hubs to survive power interruption. A typical signal chain: sensor -> instrumentation amp -> PIC18F242T ADC -> UART/Modbus to host PLC.
Recommended
Small BLDC / Stepper Motor Control
The PIC18F242T-I/SO is well suited for small brushless DC and stepper motor control in fans, pumps and small appliances. The PIC18F's CCP/PWM modules generate complementary PWM up to 40 MHz, while the 10 MIPS throughput keeps the 6-step or sine commutation loop under 100 us - critical for smooth torque at 3,000+ RPM. With 25 I/O the device drives three half-bridges directly through gate drivers, reads back-Hall sensors or back-EMF, and communicates over USART with the host controller. The 4.2V-5.5V supply is compatible with 5V gate drivers such as the MCP14 family, simplifying the analog/digital power tree. Industrial temperature grade ensures reliable fan and pump operation in enclosed environments.
Recommended
USB-to-UART Bridge / Serial Converter
The PIC18F242T-I/SO serves as a USB-to-UART bridge controller where the on-chip USART and MSSP peripherals translate USB CDC traffic into RS-232/485 levels for legacy equipment. At 40 MHz the device comfortably handles 115200 baud and higher without buffering overrun, and 16 KB FLASH fits both the CDC stack and any device-specific protocol parser. The 25 I/O are sufficient for RTS/CTS handshaking plus status LEDs. Industrial temperature and surface-mount 28-SOIC make the part appropriate for DIN-rail-mounted industrial adapters. The same firmware architecture can be extended to Modbus RTU or DMX512 conversion using the USART and CCP timers.
Recommended
Battery Chargers with CC/CV Profiling
In CC/CV battery charger designs the PIC18F242T-I/SO monitors charge current via the 10-bit ADC, regulates a buck converter using PWM, and communicates state-of-charge over UART or LEDs. The 4.2V-5.5V operating range aligns with single-cell Li-ion or 2-cell NiMH charging rails, and the 25 I/O drive 4-quadrant displays and safety interlocks. The 16 KB FLASH accommodates customer-specific charging profiles (Li-ion, LiFePO4, lead-acid) without external storage. nanoWatt sleep modes allow the charger to remain plugged in for months without deep-discharging the cell when idle. Industrial temperature rating supports outdoor solar charge controller applications.
Recommended
Embedded HMI with Character LCD & Keypad
The PIC18F242T-I/SO is a natural choice for low-cost HMI panels with character LCDs (HD44780-based 16x2 or 20x4) and 4x4 matrix keypads. The MSSP peripheral drives the LCD in 4-bit parallel mode while USART remains free for host communication. The 25 I/O deliver enough pins for the LCD data/control plus row/column scanning without a key-scan expander. At 40 MHz the menu-update loop completes in microseconds, leaving headroom for backlight PWM and buzzer control via CCP. Industrial -40C to +85C operation suits outdoor kiosks and appliance front panels.
Recommended
Automotive Body Electronics (Non-Safety)
Although the PIC18F242T-I/SO is not AEC-Q100 qualified, it is widely used in non-safety automotive body applications such as interior lighting controllers, seat-position memory, and aftermarket accessory modules. The 4.2V-5.5V supply is compatible with 12V automotive rails after the LDO, and the 25 I/O drive LED strings and small relays. The -40C to +125C extended temperature variants ("-E" parts) extend suitability to under-hood or cabin environments. For safety-critical ECUs the AEC-Q100 qualified PIC18F-K series parts are recommended instead.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F242T-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F242-I/SO | PIC18F252T-I/SO | PIC18F2420T-I/SO | PIC18F23K22T-I/SO | PIC18F2520T-I/SO |
|---|---|---|---|---|---|---|
| Package | 28-SOIC | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program FLASH | 16 KB | 16 KB | 32 KB | 16 KB | 8 KB | 32 KB |
| RAM | 768 bytes | 768 bytes | 1536 bytes | 768 bytes | 512 bytes | 1536 bytes |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| Maximum CPU Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 64 MHz | 40 MHz |
| I/O Pins | 25 | 25 | 25 | 25 | 24 | 25 |
| ADC Channels | 5 | 5 | 5 | 5 | 9 | 8 |
| Supply Voltage | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 4.2 V to 5.5 V | 2.0 V to 5.5 V | 2.3 V to 5.5 V | 2.0 V to 5.5 V |
| 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 | -40 C to +85 C |
Key Differentiators
- Mature long-life-cycle part with 25 I/O (vs PIC18F23K22T-I/SO)
- Cost-optimized 16 KB FLASH for compact firmware (vs PIC18F252T-I/SO)
- Industrial -40C to +85C temperature range (vs PIC18F2420T-I/SO)
Design Notes
Decouple VDD (pin 20) and AVSS/AVDD pair with a 100 nF ceramic placed within 5 mm of the package plus a bulk 10 uF tantalum or aluminum polymer. The PIC18F242 ADC reference VREF+/VREF- (RA3/RA2) requires a low-impedance source; a 10 uF + 100 nF combination on VREF+ reduces ADC gain error and improves low-input readings. Avoid routing digital signals under the ADC reference traces to minimize crosstalk. For battery-backed designs leverage nanoWatt Sleep mode (typical <1 uA) by gating unused peripherals through PMD bits.
Use a 4-layer stack-up with a continuous ground plane beneath the SOIC to provide low-impedance return paths for the high-speed digital edges. Route the 40 MHz crystal traces (OSC1/OSC2) short and symmetric with the load capacitors (typically 22 pF for HS mode, 15 pF for XT) placed within 5 mm of the chip. Keep the MCLR pull-up (10 kohm to VDD) and 100 nF cap close to pin 1 to ensure clean reset and reliable ICSP programming.
The 28-SOIC land pattern follows JEDEC SO-127 with 1.27 mm pitch. Maintain at least 0.2 mm clearance between SOIC leads and adjacent signal traces for wave-solder manufacturing. Place the ICSP header (PGD/PGC/MCLR/VSS/VDD) on a 0.1 inch grid for standard 6-pin RJ-12 programming connectors. Route the analog inputs (AN0-AN4) away from PWM outputs (CCP1/CCP2) and high-current digital lines; a guard ring tied to analog ground around the analog traces further reduces ADC noise pickup.
Do not exceed the absolute maximum VDD of 7.0 V or drive any I/O pin above VDD or below VSS even during power-up; latch-up may result. The MSSP SPI/I2C pins (RC3/RC4/RC5) are 5V-tolerant only when VDD >= 4.5 V - below this, avoid 5V pull-ups. Configuration word programming must include the correct oscillator selection (HS/XT/RC/INT) and the watchdog timer enable bit to match the application; an unconfigured CONFIG defaults to RC oscillator and PWRT enabled.
For USART communications above 115200 baud, ensure the baud-rate error stays under +/-2% by selecting the SPBRG value and BRGH bit per the datasheet formula; using the internal 8 MHz RC oscillator without calibration typically yields >2% baud error. For long USART cables, add a 100 ohm series resistor at the TX pin to damp reflections. For I2C buses above 400 kHz, use 4.7 kohm pull-ups and verify that the rise time stays below 300 ns per the I2C specification.
Compliance Information
RoHS compliant and lead-free per Microchip product page. Not AEC-Q100 qualified; for automotive safety applications use AEC-Q100 qualified PIC18F-K series parts. Industrial temperature grade -40C to +85C only.
