PIC18F27K42-I/ML - 8-Bit 64MHz 128KB Flash MCU | Microchip
MPN: PIC18F27K42-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.33 | $3.33 |
| 10 | $2.95 | $29.50 |
| 100 | $2.4 | $240.00 |
| 500 | $2.1 | $1,050.00 |
| 1,000 | $1.85 | $1,850.00 |
PIC18F27K42-I/ML Overview
An 8-bit PIC microcontroller (MCU) is a small, self-contained computer-on-a-chip built around an 8-bit data path and Harvard architecture. Within the embedded hierarchy, it sits under MCU -> microcontroller -> embedded processor -> semiconductor. PIC18F parts are Microchip's mid-range 8-bit family aimed at general-purpose and low-power embedded designs, bridging the 8-bit PIC16/16F and 16-bit dsPIC families.
Key specifications include a 64 MHz maximum CPU clock (16 MIPS), 2.3 V to 5.5 V supply voltage with operation down to 1.8 V in LF variants, 12-bit ADC2 with up to 35 channels and automated post-processing, a 5-bit and 12-bit DAC, four 16-bit timers, two CCP/PWM modules, hardware CVD for capacitive touch, DMA, vector interrupts, and a Device Information Area (DIA). The QFN-28 6x6 mm package provides a compact thermal pad footprint suitable for space-constrained designs.
Architecturally, the PIC18F27K42 uses an enhanced mid-range core with a hardware multiplier, indexed addressing, and C-optimized architecture, enabling efficient compiled C code with the MPLAB XC8 compiler. The integrated Direct Memory Access (DMA) controller can move data between peripherals and memory without CPU intervention, freeing the core for application logic and lowering active-mode current draw. The ADC2 block performs averaging, oversampling, threshold comparison, and filtering in hardware, which is uncommon in 8-bit MCUs.
Typical applications include IoT sensor nodes, low-power battery-powered instrumentation, home appliances, industrial control, capacitive touch user interfaces, LED lighting controllers, automotive body electronics, and USB-to-UART bridge firmware when paired with the on-chip UART. The XLP features (sleep currents in the nA range, IDLE and DOZE modes) make it especially attractive for energy-harvesting and Always-On designs.
A practical design consideration is that the QFN-28 exposed pad must be soldered to a sufficiently large copper pour to meet thermal and electrical ground requirements; otherwise, self-heating and EMI may degrade ADC readings. When migrating from the PIC18F27K40 family, confirm peripheral pinout compatibility because the K42 added several new peripherals with remapped I/O.
This page synthesizes distributor pricing, datasheet cross-references, drop-in alternatives from the same PIC18F2xK42 family, and practical design notes not found in the manufacturer datasheet, helping engineers evaluate the PIC18F27K42-I/ML in context.
Drop-in alternatives for PIC18F27K42-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 PIC18F27K42-I/ML (same form factor and footprint) — differing in Package, Core, ADC, DAC, Comparators.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F27K42-E/ML
✅ Drop-In✓ In Stock
$1.92 / Unit
View Datasheet →PIC18F27K42T-I/ML
✅ Drop-In✓ In Stock
$2.45 / Unit
View Datasheet →PIC18F27K40T-I/ML
✅ Drop-In✓ In Stock
$1.95 / Unit
View Datasheet →PIC18F27K42-I/SP
✅ Drop-In✓ In Stock
$2.62 / Unit
View Datasheet →PIC18F27K42-E/SP
✅ Drop-In✓ In Stock
$2.21 / Unit
View Datasheet →PIC18F27K42-E/SS
✅ Drop-In✓ In Stock
$1.58 / Unit
View Datasheet →PIC18F27K42-I/ML Maximum Ratings & Electrical Characteristics
| Core | PIC18F enhanced mid-range 8-bit |
| CPU Architecture | Harvard, 8-bit data path, 16-bit instructions |
| Maximum CPU Frequency | 64 MHz (16 MIPS) |
| Program Memory (Flash) | 128 KB (64K x 16 words) |
| Data RAM | 8 KB |
| Data EEPROM | 1 KB |
| Supply Voltage (VDD) | 2.3 V to 5.5 V |
| Operating Temperature (I grade) | -40C to +85C |
| Package | 28-pin QFN (ML) 6x6 mm with exposed pad |
| ADC | 12-bit ADC2 with computation, up to 35 external channels |
| DAC | 5-bit and 12-bit DAC |
| Comparators | On-chip comparators (CVD-capable) |
| Timers | 4 x 16-bit timers |
| PWM / CCP | 2 CCP modules, 10-bit PWM |
| Communication | UART, SPI, I2C (multiple instances) |
| DMA | Hardware DMA controller |
| Interrupts | Vectored interrupts with configurable priority |
| Capacitive Touch | Hardware CVD (Capacitive Voltage Divider) |
| Low-Power Technology | XLP (eXtreme Low Power) with IDLE/DOZE/Sleep modes |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
PIC18F27K42-I/ML Pin Configuration
| Pin 1 | RA0/ANA0 — Port A bit 0 / analog input channel 0 / IOC |
| Pin 2 | RA1/ANA1 — Port A bit 1 / analog input channel 1 |
| Pin 3 | RA2/ANA2 — Port A bit 2 / analog input channel 2 |
| Pin 4 | RA3/ANA3 — Port A bit 3 / analog input channel 3 |
| Pin 5 | RA4/ANA4 — Port A bit 4 / analog input channel 4 |
| Pin 6 | RA5/ANA5 — Port A bit 5 / analog input channel 5 |
| Pin 7 | RA6 — Port A bit 6 |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RA7 — Port A bit 7 |
| Pin 10 | RB0 — Port B bit 0 |
| Pin 11 | RB1 — Port B bit 1 |
| Pin 12 | RB2 — Port B bit 2 |
| Pin 13 | RB3 — Port B bit 3 |
| Pin 14 | RB4 — Port B bit 4 |
| Pin 15 | RB5 — Port B bit 5 |
| Pin 16 | RB6 — Port B bit 6 / ICSPCLK |
| Pin 17 | RB7 — Port B bit 7 / ICSPDAT |
| Pin 18 | VSS — Ground reference (second pad for thermal) |
| Pin 19 | VDD — Positive supply voltage |
| Pin 20 | VDD — Positive supply voltage (second VDD pin) |
| Pin 21 | RC0 — Port C bit 0 |
| Pin 22 | RC1 — Port C bit 1 |
| Pin 23 | RC2 — Port C bit 2 |
| Pin 24 | RC3 — Port C bit 3 |
| Pin 25 | RC4 — Port C bit 4 |
| Pin 26 | RC5 — Port C bit 5 |
| Pin 27 | RC6 — Port C bit 6 |
| Pin 28 | RC7 — Port C bit 7 |
Typical Applications
PIC18F27K42-I/ML is suitable for 7 applications: Battery-Powered IoT Sensor Node, Capacitive Touch User Interface, Industrial Control and Monitoring, Home Appliance Controller, LED Lighting Controller, Automotive Body Electronics, USB-to-UART Bridge and Communication Hub.
Battery-Powered IoT Sensor Node
The PIC18F27K42-I/ML is well-suited for battery-powered IoT sensor nodes because its XLP (eXtreme Low Power) technology delivers nA-range sleep currents and the ADC2 with computation block can average and threshold-compare sensor readings in hardware while the core stays in Sleep mode. With 128 KB of Flash and 8 KB of RAM, the part can run a full IoT firmware stack including a state machine, calibration tables, and small protocol handlers without external memory. Typical configurations pair the MCU with a UART- or SPI-connected sensor (temperature, humidity, accelerometer) and report on a periodic wake cycle. The QFN-28 6x6 mm footprint fits inside compact sensor housings and supports operation down to 2.3 V on two AA cells, making it ideal for Always-On wireless nodes.
Recommended
Capacitive Touch User Interface
The PIC18F27K42-I/ML is a strong fit for capacitive touch interfaces because its hardware CVD (Capacitive Voltage Divider) module automates touch sampling on any analog-capable pin, eliminating the need for an external touch controller. The 12-bit ADC2 with computation can post-process touch signals (averaging, threshold comparison) without CPU wake-up, keeping average power low in always-on appliances. Up to 35 channels support medium-sized button matrices or slider/trackpad layouts. The integrated DMA controller moves touch samples directly to memory, freeing the core for HMI logic. Reference designs typically pair this MCU with LED drivers and a UART-connected host processor for full touch-UI subsystems.
Recommended
Industrial Control and Monitoring
In industrial control applications, the PIC18F27K42-I/ML provides reliable 8-bit processing with a 64 MHz core, 12-bit ADC2 for accurate sensor measurement, and a hardware DMA engine that handles time-critical data transfer to and from peripherals without CPU intervention. The vectored interrupt controller with configurable priority lets time-critical tasks preempt lower-priority firmware, and the rich peripheral set (UART, SPI, I2C) interfaces easily to RS-485 transceivers, sensor front-ends, and HMI displays. The QFN-28 (ML) 6x6 mm package with exposed thermal pad dissipates heat effectively in enclosed industrial enclosures, while the -40C to +85C industrial temperature rating covers most factory floor installations.
Recommended
Home Appliance Controller
The PIC18F27K42-I/ML fits home appliance designs such as washing machines, dishwashers, and microwave ovens where a low-cost 8-bit MCU must drive user interfaces, motor control signals, and safety sensors. Its 16-bit PWM and CCP modules can generate control signals for small BLDC or universal motors, while the ADC2 monitors temperature, water level, and door-state sensors with hardware averaging for noise immunity. The XLP modes keep standby current below typical Energy Star limits for always-on appliances. Microchip's MPLAB XC8 toolchain with free optimizations supports rapid firmware development for consumer appliance production schedules.
Recommended
LED Lighting Controller
The PIC18F27K42-I/ML is a good choice for smart LED lighting controllers where multiple PWM channels drive LED strings, and firmware must support dimming, color-mixing, and connectivity protocols. Its hardware 16-bit timers and CCP/PWM modules produce precise dimming signals without jitter, while UART and I2C interfaces connect to wireless modules (Bluetooth, Wi-Fi, or sub-GHz radios) for smart-bulb integration. The 128 KB Flash comfortably holds ZigBee, BLE, or proprietary lighting stacks plus application logic. XLP low-power modes allow the controller to remain responsive while drawing minimal current during standby, meeting stringent energy regulations.
Recommended
Automotive Body Electronics
Although not AEC-Q100 qualified itself, the PIC18F27K42-I/ML family shares peripherals and firmware patterns with its automotive-graded K42 siblings and is often used in body-electronics prototypes and pre-production development. The integrated CAN-friendly peripherals (via SPI to external CAN transceivers), 12-bit ADC2 for sensor monitoring, and PWM channels for motor-driven accessories (windows, mirrors, seats) make it a flexible development platform. The -40C to +85C industrial temperature range suits non-engine-compartment automotive applications, and engineers can migrate validated firmware to the AEC-Q100 K42 automotive variants once the design is production-ready.
Recommended
USB-to-UART Bridge and Communication Hub
The PIC18F27K42-I/ML can serve as a USB-to-UART, SPI-to-I2C, or general communication bridge in industrial gateways and embedded debug tools, leveraging its multiple UART, SPI, and I2C instances running simultaneously. The hardware DMA engine moves serial data between peripheral FIFOs and memory with minimal CPU intervention, freeing the core for protocol handling and flow control. The 8 KB RAM buffers full protocol stacks, while 128 KB Flash holds bootloader and application images for field-upgradable bridges. The QFN-28 (ML) 6x6 mm footprint fits on compact bridge modules alongside a USB connector and ESD protection diodes.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F27K42-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F27K42-E/ML | PIC18F27K40T-I/ML | PIC18F27K42T-I/ML | PIC18F27K42-I/SP |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-pin QFN (ML) 6x6 mm | 28-pin QFN (ML) 6x6 mm - same | 28-pin QFN (ML) 6x6 mm - same | 28-pin QFN (ML) 6x6 mm - same | 28-pin SPDIP (through-hole) |
| Flash Memory | 128 KB | 128 KB | 64 KB (-50%) | 128 KB | 128 KB |
| RAM | 8 KB | 8 KB | 8 KB | 8 KB | 8 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| Operating Temperature | -40C to +85C (I grade) | -40C to +125C (E grade) | -40C to +85C (I grade) | -40C to +85C (I grade) | -40C to +85C (I grade) |
| ADC with Computation | Yes (12-bit ADC2) | Yes | No (basic 12-bit ADC) | Yes | Yes |
| Hardware DMA | Yes | Yes | No | Yes | Yes |
| Capacitive Touch (CVD) | Yes | Yes | Yes | Yes | Yes |
| XLP Low-Power Modes | Yes | Yes | Yes | Yes | Yes |
| Unit Price (qty 1) | USD 3.33 | USD 3.50 - 3.80 | USD 2.80 - 3.10 | USD 3.33 (tape/reel) | USD 3.20 - 3.50 |
Key Differentiators
- Larger Flash memory than the K40 sibling (vs PIC18F27K40T-I/ML)
- ADC2 hardware computation block unavailable on K40 (vs PIC18F27K40T-I/ML)
- QFN-28 with exposed pad improves thermal and noise performance (vs PIC18F27K42-I/SP)
Design Notes
The QFN-28 (ML) 6x6 mm package has an exposed thermal pad on the underside that must be soldered to a PCB copper pour of at least 1 square inch to meet the datasheet thermal resistance and to serve as the electrical ground reference. Estimated: without the exposed pad properly soldered, theta_JA can rise above 100 C/W, causing self-heating that degrades ADC2 readings. Recommended pour area is 4-6 cm squared across multiple inner layers stitched with thermal vias.
Decouple VDD/VSS pairs with 100 nF X7R ceramic capacitors placed as close as possible (within 3 mm) to each VDD pin, plus a bulk 4.7 uF or 10 uF tantalum/ceramic capacitor on the main VDD rail. The PIC18F27K42-I/ML has two VDD pins (pins 19 and 20); both must be decoupled separately. Place the bulk capacitor adjacent to where the supply enters the PCB to minimize switching transients during core wake-up from Sleep mode.
Keep ADC analog traces short and routed away from digital switching signals (PWM, SPI clock) to minimize coupling into the 12-bit ADC2. Use a ground pour under the MCU and stitch the analog and digital ground domains together at a single point near the MCU VSS pin. For capacitive touch (CVD) designs, route the touch electrodes with a hatch ground fill and keep guard traces within 2 mm of the electrode for noise immunity.
Configuration bits (fuses) must be set correctly before code can execute; in particular, RSTOSC, FEXTOSC, and WDTE settings determine the clock source and watchdog behavior on power-up. A common mistake is leaving the MCU in a non-configured state where it appears dead; in-circuit serial programming (ICSP) via RB6/ICSPCLK and RB7/ICSPDAT is the recovery path. Also verify that the PICKit or MPLAB SNAP programmer is supplying VDD during programming if the target board lacks its own power.
When routing the external 32.768 kHz crystal for the secondary oscillator (SOSC) used by the Real-Time Clock and Calendar (RTCC), place the crystal within 5 mm of the SOSCO/SOSCI pins and shield the traces with a ground guard ring to avoid capacitive loading from adjacent signals. Estimated: stray capacitance above 5 pF will pull the oscillator off-frequency by 10-20 ppm, degrading RTC accuracy.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified (industrial grade only); for automotive use, choose AEC-Q100 qualified PIC18F variants from the K42 family. Halogen-free matte-tin plating on QFN substrate.
