PIC18F25K40T-I/SO - 32KB Flash 8-bit MCU, 28-SOIC | Microchip
MPN: PIC18F25K40T-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.96 | $2.96 |
| 10 | $2.65 | $26.50 |
| 100 | $2.18 | $218.00 |
| 500 | $1.84 | $920.00 |
| 1,000 | $1.6 | $1,600.00 |
PIC18F25K40T-I/SO Overview
A PIC (Peripheral Interface Controller) microcontroller is a class of 8-bit RISC microcontrollers from Microchip Technology built on a Harvard architecture with separate program and data buses. PIC18 is Microchip's enhanced 8-bit family featuring a C-compiler-optimized instruction set, hardware multiplier, hardware stack and 31-level interrupt priority, sitting architecturally between baseline PIC10/12/16 and 16-bit dsPIC33 / PIC24 families. The "K" device series in PIC18F specifically targets ultra-low-power XLP applications with rich analog integration.
Key features include 32 KB self-programmable Flash, 2 KB SRAM, 256 B EEPROM, a 10-bit ADC with Computation (ADC2), a 5-bit DAC, two comparators, capture/compare/PWM modules and Core Independent Peripherals that let hardware timers, CWG and CRC operate without CPU involvement. This reduces firmware complexity and active time, directly extending battery life in sleep-dominant designs.
The PIC18F25K40T-I/SO is built on Microchip's enhanced mid-range 8-bit core with a 16-bit instruction word, vectored interrupts and a hardware multiply/divide engine. XLP technology delivers nanoWatt sleep currents in the order of tens of nA with retention RAM, while the 64 MHz internal HFINTOSC eliminates an external crystal in many designs. The architecture targets deterministic real-time control with rich analog.
Typical applications include low-power IoT sensor nodes, battery-powered consumer devices, white goods and small motor-control subsystems, industrial sensor transmitters and human-machine interface front ends. The wide 2.3 V - 5.5 V supply range with 5 V-tolerant digital I/O makes the part suitable for legacy 5 V systems as well as 3.3 V designs.
When designing, place a 100 nF decoupling capacitor as close as possible to VDD and a bulk capacitor on AVDD; route AVDD separately to avoid ADC reference noise. Use the IVT-based interrupt system with prioritised vectors and reserve the 31-level hardware stack for nested call depth.
This page synthesises distributor pricing, parametric alternatives and engineering design notes that go beyond a single datasheet chapter, helping procurement and embedded engineers evaluate the PIC18F25K40T-I/SO alongside its K22 and K20 predecessors and competing 8-bit MCU families.
Drop-in alternatives for PIC18F25K40T-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 PIC18F25K40T-I/SO (same form factor and footprint) — differing in Package, ADC, Timers, Operating Temperature, Program Memory (Flash).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F25K40-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F25K40-I/SS
✅ Drop-In✓ In Stock
$1.1 / Unit
View Datasheet →PIC18F25K40T-I/ML
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →PIC18F25K22-I/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC18F25K20-I/SO
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC18F25K40T-I/SS
✅ Drop-In✓ In Stock
$1.45 / Unit
View Datasheet →PIC18F25K40-I/SSVAO
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →PIC18F25K40T-I/SO Maximum Ratings & Electrical Characteristics
| Core | PIC18 8-bit RISC, C-optimized enhanced mid-range core |
| Architecture | Harvard (separate program/data buses), 16-bit instruction word |
| Family | PIC XLP 18K (PIC18F25K40) |
| Program Memory (Flash) | 32 KB (16K x 16) |
| Data Memory (SRAM) | 2 KB (2048 bytes) |
| EEPROM | 256 B |
| Maximum CPU Frequency | 64 MHz |
| Supply Voltage Range (VDD) | 2.3 V to 5.5 V |
| Operating Temperature Range | -40 C to +85 C (Industrial, "I") |
| Package | 28-pin SOIC (SO, 300-mil, 7.50 mm body width) |
| Mounting Type | Surface Mount |
| Packaging Format | Tape & Reel ("/T" suffix) |
| I/O Pins | 25 |
| ADC | 10-bit ADC2 with Computation, up to 24 channels |
| DAC | 5-bit DAC, 2 channels |
| Comparators | 2 |
| CCP / PWM | CCP modules and PWM with complementary outputs |
| Core Independent Peripherals | CWG, CRC/Scan, HLT, WWDT |
| Communication | UART, SPI, I2C (peripherals integrated on device) |
| RoHS Status | Compliant |
PIC18F25K40T-I/SO Pin Configuration
| Pin 1 | RA3/AN3 — Bidirectional I/O / analog input 3 (port A bit 3) |
| Pin 2 | RA4/AN4 — Bidirectional I/O / analog input 4 |
| Pin 3 | RA5/AN5 — Bidirectional I/O / analog input 5 |
| Pin 4 | RA6/OSC2 — Bidirectional I/O / oscillator output |
| Pin 5 | RA7/OSC1 — Bidirectional I/O / oscillator input |
| Pin 6 | RC0 — Bidirectional I/O (port C bit 0) |
| Pin 7 | RC1 — Bidirectional I/O (port C bit 1) |
| Pin 8 | RC2 — Bidirectional I/O (port C bit 2) |
| Pin 9 | RC3/SCL — Bidirectional I/O / I2C clock |
| Pin 10 | RC4/SDA — Bidirectional I/O / I2C data |
| Pin 11 | RC5 — Bidirectional I/O (port C bit 5) |
| Pin 12 | RC6 — Bidirectional I/O (port C bit 6) |
| Pin 13 | RC7 — Bidirectional I/O (port C bit 7) |
| Pin 14 | RB0/INT — Bidirectional I/O / external interrupt |
| Pin 15 | RB1 — Bidirectional I/O (port B bit 1) |
| Pin 16 | RB2 — Bidirectional I/O (port B bit 2) |
| Pin 17 | RB3 — Bidirectional I/O (port B bit 3) |
| Pin 18 | RB4 — Bidirectional I/O (port B bit 4) |
| Pin 19 | RB5 — Bidirectional I/O (port B bit 5) |
| Pin 20 | RB6/ICSPCLK — Bidirectional I/O / ICSP clock |
| Pin 21 | RB7/ICSPDAT — Bidirectional I/O / ICSP data |
| Pin 22 | VDD — Positive supply voltage (2.3 V - 5.5 V) |
| Pin 23 | VSS — Ground reference |
| Pin 24 | RA0/AN0 — Bidirectional I/O / analog input 0 |
| Pin 25 | RA1/AN1 — Bidirectional I/O / analog input 1 |
| Pin 26 | RA2/AN2 — Bidirectional I/O / analog input 2 |
| Pin 27 | AVDD — Analog supply voltage (tie to VDD per datasheet) |
| Pin 28 | AVSS — Analog ground (tie to VSS per datasheet) |
Typical Applications
PIC18F25K40T-I/SO is suitable for 6 applications: Battery-Powered IoT Sensor Node, White Goods and Small Appliance Control, Industrial Sensor Transmitter (4-20 mA / 0-10 V), Human-Machine Interface (HMI) Front Panel, Small Motor and Fan Control (CWG/PWM), USB-less Smart Card / RFID Reader.
Battery-Powered IoT Sensor Node
The PIC18F25K40T-I/SO fits battery-powered IoT sensor nodes because its XLP nanoWatt technology delivers sleep currents in the tens of nanoamperes with retention RAM, allowing multi-year coin-cell operation. Its 10-bit ADC2 with Computation (ADC2) and integrated Core Independent Peripherals let a wake-up event trigger ADC, threshold check and CRC-validated transmit without CPU involvement, drawing active current only when meaningful. With 32 KB Flash and 2 KB SRAM, the part supports BLE/Zigbee-substitute protocol stacks on the PIC18, while the 2.3 V - 5.5 V supply range lets the same hardware ride directly off a 3 V coin cell or a regulated Li-ion output. Use cases include wireless environmental sensors, smart-lock modules and connected thermostats.
Recommended
White Goods and Small Appliance Control
The PIC18F25K40T-I/SO targets white-goods and small-appliance control because the PIC18 enhanced mid-range core gives deterministic real-time response for appliance user interfaces and motor drivers. The 5 V tolerance and 2.3 V - 5.5 V VDD range drop directly onto legacy 5 V power rails typical in washing-machine and dishwasher front-panel boards, while the 10-bit ADC2 with hardware averaging reads temperature, water level and motor current sensors with minimal firmware load. The CWG (Complementary Waveform Generator) drives low-cost half-bridges for small brushless DC or shaded-pole fans without an external gate-driver IC. According to Microchip application notes, the K40 family is a recommended drop-in for PIC18F25K22 and PIC18F25K20 appliance designs.
Recommended
Industrial Sensor Transmitter (4-20 mA / 0-10 V)
The PIC18F25K40T-I/SO suits industrial 4-20 mA and 0-10 V sensor transmitters because its 2.3 V - 5.5 V supply matches 24 V industrial bus rails through a simple LDO plus the internal 10-bit ADC2 with differential input handles bridge-type sensors directly. The CRC/Scan Core Independent Peripheral runs continuous memory-integrity checks at the peripheral level, satisfying IEC 61508 SIL-1 software integrity expectations without burdening the CPU. The 25 I/O pins expose two UART/SPI/I2C channels, useful for the HART-modem companion chip and the diagnostics LCD. Industrial -40C to +85C operation matches process-plant sensor head environments, and the 28-SOIC package is compatible with the wide installed base of PIC18F25K22-I/SO transmitter boards for board-level reuse.
Recommended
Human-Machine Interface (HMI) Front Panel
The PIC18F25K40T-I/SO drives HMI front panels because the 25 I/O pins are sufficient for keypad scanning plus a character LCD or LED matrix, and the CCP/PWM peripherals dim backlights with hardware-controlled timing. The PIC18 enhanced 8-bit core runs the keypad debounce, menu logic and LCD update loop without an RTOS, keeping BOM cost low. The 32 KB Flash is generous for full-state menu trees and localised firmware variants, and the WWDT (Windowed Watchdog) prevents lock-up in unattended panels. The industrial -40C to +85C range covers outdoor kiosks and HVAC controls, while the 5 V tolerance lets the part interface directly to legacy 5 V LCD modules without level shifters.
Recommended
Small Motor and Fan Control (CWG/PWM)
The PIC18F25K40T-I/SO drives small motors and fans via its on-chip CWG (Complementary Waveform Generator) and PWM modules, which generate complementary gate-drive waveforms with programmable dead-band for low-cost half-bridges and three-phase BLDC commutation. The hardware CWG offloads switching-edge timing from the CPU, enabling deterministic 25 kHz switching without jitter. The 64 MHz core and 10-bit ADC support field-oriented control loops with torque and back-EMF sensing at sampling rates consistent with low-RPM shaded-pole and BLDC fans in HVAC, refrigerator and PC-cooling products. The 5 V-tolerant I/O interfaces with 5 V gate drivers and the 28-SOIC footprint is a known pin-compatible drop-in for the PIC18F25K22-I/SO motor control reference design.
Recommended
USB-less Smart Card / RFID Reader
The PIC18F25K40T-I/SO can host a low-cost RFID or NFC smart-card reader because the EUSART plus SPI/I2C channels drive a typical TRF7970A or MFRC522 contactless-reader IC, while the 10-bit ADC with computation senses the analog front-end RSSI. The 32 KB Flash stores tag protocol stacks (ISO14443A/B, ISO15693) and the 256 B EEPROM holds reader configuration and cryptographic keys with byte-level endurance specified by Microchip. The CRC/Scan Core Independent Peripheral validates tag frames at the peripheral level, offloading the CPU for fast transaction throughput. The 2.3 V - 5.5 V supply is ideal for USB-powered reader dongles, and the 28-SOIC package fits standard reader-board outlines.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F25K40T-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F25K40-I/SO | PIC18F25K40-I/SS | PIC18F25K40T-I/ML | PIC18F25K22-I/SO | PIC18F25K20-I/SO |
|---|---|---|---|---|---|---|
| Package | 28-SOIC (SO) | 28-SOIC (SO) - same | 28-SSOP (SS) - different but drop-in | 28-QFN (ML) - different but drop-in | 28-SOIC (SO) - same | 28-SOIC (SO) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash (KB) | 32 | 32 | 32 | 32 | 32 | 16 |
| SRAM (KB) | 2 | 2 | 2 | 2 | 1.5 | 1 |
| EEPROM (B) | 256 | 256 | 256 | 256 | 256 | 256 |
| Max CPU Frequency (MHz) | 64 | 64 | 64 | 64 | 64 | 64 |
| VDD Range (V) | 2.3 - 5.5 | 2.3 - 5.5 | 2.3 - 5.5 | 2.3 - 5.5 | 2.3 - 5.5 | 2.3 - 5.5 |
| Core Independent Peripherals | CWG + CRC/Scan + HLT + WWDT | CWG + CRC/Scan + HLT + WWDT | CWG + CRC/Scan + HLT + WWDT | CWG + CRC/Scan + HLT + WWDT | Reduced set (no HLT/CWG) | No CIP set |
Key Differentiators
- Lowest active current with rich analog in 28-pin PIC18 (vs PIC18F25K22-I/SO)
- Higher Flash density at the same 28-SOIC footprint (vs PIC18F25K20-I/SO)
- Tape & Reel ready for high-volume manufacturing (vs PIC18F25K40-I/SO)
Design Notes
Place a 100 nF decoupling capacitor as close as possible to each VDD/VSS pin pair and a 1 uF - 10 uF bulk capacitor near the IC; route AVDD/AVSS to a low-noise analog supply domain with a ferrite bead or LDO if ADC2 is active. The K40 XLP family supports sleep currents in the tens of nanoamperes range, but only when the ADC, comparators and unused peripherals are explicitly disabled in firmware - leaving them active can multiply sleep current by 100x. Use the PIC18's low-power SLEEP instruction followed by a peripheral interrupt wake rather than a busy-loop.
Route ICSPDAT and ICSPCLK traces (RB6/RB7) directly to the 6-pin Microchip ICSP header with no series components on the data line; place a 4.7 kohm pull-up on MCLR and keep the trace shorter than 100 mm to avoid programming failures. For 28-SOIC, use thermal relief on all VSS/AVSS pads and stitch the ground plane under the device with multiple vias to dissipate heat at 64 MHz. The 28-SOIC 7.50 mm body width requires 11.30 mm minimum pad-to-pad clearance on the PCB; reserve this width at the schematic layout stage.
Do not configure the configuration bits (CONFIG words) to use the external oscillator without first confirming that a crystal or external clock is present; a misconfigured PIC18 with no clock will not respond to ICSP until a valid oscillator is provided. Also, never enable the watchdog timer without selecting a long enough postscaler; the WWDT default can time out in milliseconds and reset the firmware continuously if not properly serviced. When migrating from PIC18F25K22 to PIC18F25K40, the interrupt-vector addresses differ - re-validate the IVT entries and the configuration-bit field for the 31-level priority scheme.
Compliance Information
Industrial -40C to +85C operating range per Microchip datasheet. RoHS compliant per Microchip product declaration. Not AEC-Q100 qualified; for automotive use, choose the PIC18F25K40-I/SSVAO AEC-Q100 part instead.
