PIC18F252-I/SO - 8-bit 40MHz 32KB Flash MCU | Microchip | 28-SOIC
MPN: PIC18F252-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.1 | $7.10 |
| 10 | $6.32 | $63.20 |
| 100 | $5.2 | $520.00 |
| 500 | $4.55 | $2,275.00 |
| 1,000 | $3.95 | $3,950.00 |
PIC18F252-I/SO Overview
A microcontroller (MCU) is a single-chip computer integrating a CPU core, program memory (Flash/ROM), data memory (RAM/EEPROM), and programmable I/O peripherals on one die. PIC microcontrollers sit at the foundation of embedded control, spanning consumer appliances, automotive body electronics, industrial sensors, and medical devices - the 8-bit PIC18 family specifically targets applications needing higher performance and more peripherals than the baseline PIC16 family while remaining easy to program in C.
Key features of the PIC18F252 include 32 KB of on-chip Flash program memory (16K x 16 words), 1536 bytes of SRAM, 256 bytes of EEPROM for non-volatile data storage, 23 digital I/O pins, a 10-bit A/D converter with up to 5 input channels, two Capture/Compare/PWM (CCP) modules, an enhanced USART, a Master Synchronous Serial Port (MSSP) configurable as SPI or I2C, and 4 timer modules. The C-compiler-friendly instruction set comprises only 77 single-word instructions, while 16-bit instructions and hardware multiply deliver the throughput advantage over the PIC16 line.
The PIC18F252 architecture uses a Harvard memory layout with separate program and data buses, allowing instruction fetch and operand read in the same cycle. Self-programming support lets the device update its own Flash in-field, and an integrated ICD (In-Circuit Debug) interface simplifies bring-up. Operating from 4.2 V to 5.5 V, it consumes approximately 16 mA at 40 MHz in active mode and drops below 1 uA in sleep.
Typical applications include industrial sensor signal conditioning, automotive body modules and instrument clusters, HVAC controllers, security alarm panels, white-goods motor control, low-end instrumentation with ADC front-ends, and USB-to-serial bridges when paired with a peripheral PHY. Designers also use the PIC18F252 in replacement of older PIC16 designs where the 16-bit instruction set, additional RAM, and enhanced peripherals unlock new features without learning a new toolchain.
Design considerations include decoupling: a 100 nF ceramic should sit within 5 mm of each power pair (VDD/VSS, AVDD/AVSS), with a bulk 10 uF near the IC. The MCLR reset pin must have a 10 kohm pull-up unless tied to a supervisor; for ICSP programming, isolate the MCLR line with a resistor divider. Unused A/D channels should be tied to ground to avoid shoot-through current.
This page combines DigiKey/Mouser pricing, Microchip product-page facts, and practical design notes curated for engineers evaluating the PIC18F252-I/SO against newer PIC18 K-series and K42 alternatives.
Drop-in alternatives for PIC18F252-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 PIC18F252-I/SO (same form factor and footprint) — differing in Package, Core Architecture, Operating Temperature, ADC, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F242-I/SO
✅ Drop-In✓ In Stock
$3.5 / Unit
View Datasheet →PIC18F252-E/SO
✅ Drop-In✓ In Stock
$5.78 / Unit
View Datasheet →PIC18F252T-I/SO
✅ Drop-In✓ In Stock
$6.91 / Unit
View Datasheet →PIC18F252-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18 (8-bit Harvard) |
| CPU Core | PIC18 RISC |
| Instruction Set Width | 16-bit (77 single-word instructions) |
| Maximum Clock Frequency | 40 MHz |
| Performance | 10 MIPS (100 ns instruction cycle) |
| Program Memory (Flash) | 32 KB (16K x 16) |
| Data Memory (SRAM) | 1536 bytes |
| Data EEPROM | 256 bytes |
| Digital I/O Pins | 23 |
| ADC | 10-bit, up to 5 channels |
| CCP/PWM Modules | 2 |
| Timers | 4 (Timer0/1/2/3) |
| Communication | Enhanced USART + MSSP (SPI/I2C) |
| Supply Voltage (VDD) | 4.2 V to 5.5 V |
| Operating Temperature | -40 C to +85 C (Industrial, 'I') |
| Package | 28-SOIC (7.50 mm body width) |
| Mounting Type | Surface Mount |
| Self-Programming | Yes (Flash, in-field) |
| ICSP / ICD | Yes (In-Circuit Serial Programming + Debug) |
| RoHS Status | Compliant |
PIC18F252-I/SO Pin Configuration
| Pin 1 | MCLR/VPP/RE3 — Master Clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0 — Digital I/O / Analog input channel 0 |
| Pin 3 | RA1/AN1 — Digital I/O / Analog input channel 1 |
| Pin 4 | RA2/AN2/VREF- — Digital I/O / Analog input channel 2 / ADC VREF- |
| Pin 5 | RA3/AN3/VREF+ — Digital I/O / Analog input channel 3 / ADC VREF+ |
| Pin 6 | RA4/T0CKI — Digital I/O / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — Digital I/O / Analog input channel 4 / SPI slave select |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/CLKI/RA7 — Oscillator input / external clock / GPIO |
| Pin 10 | OSC2/CLKO/RA6 — Oscillator output / clock out / GPIO |
| Pin 11 | RC0/T1OSO/T1CKI — Digital I/O / Timer1 oscillator output |
| Pin 12 | RC1/T1OSI/CCP2 — Digital I/O / Timer1 oscillator input / CCP2 |
| Pin 13 | RC2/CCP1 — Digital I/O / CCP1 (PWM/Capture/Compare) |
| Pin 14 | RC3/SCK/SCL — Digital I/O / MSSP SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — Digital I/O / MSSP SPI data in / I2C data |
| Pin 16 | RC5/SDO — Digital I/O / MSSP SPI data out |
| Pin 17 | RC6/TX/CK — Digital I/O / USART async transmit / clock |
| Pin 18 | RC7/RX/DT — Digital I/O / USART async receive / data |
| Pin 19 | VSS — Ground reference (second) |
| Pin 20 | VDD — Positive power supply (+5 V) |
| Pin 21 | RB0/INT0 — Digital I/O / External interrupt 0 |
| Pin 22 | RB1/INT1 — Digital I/O / External interrupt 1 |
| Pin 23 | RB2/INT2 — Digital I/O / External interrupt 2 |
| Pin 24 | RB3/CCP2 — Digital I/O / CCP2 (alternate pin) |
| Pin 25 | RB4 — Digital I/O / interrupt-on-change |
| Pin 26 | RB5 — Digital I/O / interrupt-on-change |
| Pin 27 | RB6/PGC — Digital I/O / ICSP clock / interrupt-on-change |
| Pin 28 | RB7/PGD — Digital I/O / ICSP data / interrupt-on-change |
Typical Applications
PIC18F252-I/SO is suitable for 7 applications: Industrial Sensor Node, Automotive Body Controller, HVAC Appliance Control Board, Security Alarm Panel, Low-End Instrumentation with ADC Front-End, Motor Control / PWM Driver, USB-to-Serial Bridge Bridge (with PHY).
Industrial Sensor Node
The PIC18F252-I/SO is a strong fit for industrial 4-20 mA loop-powered sensor nodes because its 5-channel 10-bit ADC delivers 1024 quantization steps over the 0-5 V input range - sufficient for sub-1% pressure, flow, and temperature readout. The MSSP configurable as SPI or I2C lets the MCU drive external EEPROM for data logging, while 1536 B of SRAM comfortably buffers one-second telemetry bursts. Industrial temperature rating (-40 C to +85 C) plus 23 GPIO ports support direct connection to HART modulators or isolated digital outputs without external bus drivers.
Recommended
Automotive Body Controller
Body control modules (BCM) for lighting, central locking, and wiper control rely on the PIC18F252-I/SO's 2 CCP/PWM channels to drive LED drivers and small DC motor bridges, while the enhanced USART handles LIN or K-Line communication with the rest of the vehicle network. Its industrial temperature rating suits cabin environments, and 32 KB Flash provides room for state-machine firmware plus diagnostic routines. Compared to a discrete logic implementation, the integrated MCU reduces BOM cost and PCB area by 40-60% on entry-level BCM designs.
Recommended
HVAC Appliance Control Board
HVAC compressor and blower controllers use the PIC18F252-I/SO to schedule compressor cycling based on 10-bit ADC temperature readings from NTC sensors, switching triac gate drives through the CCP/PWM peripherals. The 256-byte EEPROM retains user-setpoint temperatures across power cycles, while the 77-instruction PIC18 core lets engineers implement PID control loops in C with the free MPLAB XC8 compiler. Surface-mount 28-SOIC package supports compact control-board layouts common in mini-split air conditioners.
Recommended
Security Alarm Panel
Wired security alarm panels use the PIC18F252-I/SO to monitor 8-16 zones via the 10-bit ADC thresholds or GPIO interrupt lines, plus a serial EEPROM for event-log retention when mains power fails. The 32 KB Flash holds zoning logic, dialer firmware, and keypad scan routines, while the enhanced USART connects to GSM/PSTN dialers or IP communicators. Integrated ICD support lets field technicians in-system reprogram panels via the PICkit header without removing the MCU from the chassis.
Recommended
Low-End Instrumentation with ADC Front-End
Bench-top multimeters, handheld oscilloscope probes, and process calibrators use the PIC18F252-I/SO's 10-bit ADC to digitize sensor signals from op-amp front-ends, driving character LCDs via I/O expansion or SPI. The PIC18's 100 ns instruction cycle easily handles 100 Hz display refresh plus min/max capture and averaging. Industrial -40 C to +85 C rating covers factory-floor environments, while in-system self-programming allows firmware updates via the ICSP header during recalibration cycles.
Recommended
Motor Control / PWM Driver
Low-power BLDC and brushed DC motor drives up to 30 W use the PIC18F252-I/SO to generate complementary PWM signals through the CCP modules with adjustable dead-band, while ADC channels sample back-EMF for sensorless commutation. The 77-instruction PIC18 core plus hardware multiply simplifies field-oriented control (FOC) routines on small fans and pumps. Its surface-mount 28-SOIC footprint suits compact inverter PCBs found in appliance pumps, computer fans, and small e-bike controllers.
Recommended
USB-to-Serial Bridge Bridge (with PHY)
Engineers pair the PIC18F252-I/SO with an external USB transceiver such as the MCP2200 or MCP2221 to build USB-to-UART bridges for legacy serial peripherals. The PIC18F252's enhanced USART supports baud rates up to 1 Mbps, and 23 GPIO pins can bit-bang RS-485 direction control, RTS/CTS handshaking, or status LEDs. The 32 KB Flash accommodates USB-CDC class drivers written in XC8, eliminating the need for an external EEPROM or bootloader IC in many designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F252-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F242-I/SO | PIC18F252-E/SO | PIC18F252T-I/SO | PIC18F252-I/SP |
|---|---|---|---|---|---|
| Package | 28-SOIC | 28-SOIC (same) | 28-SOIC (same) | 28-SOIC (same) | 28-SPDIP (through-hole) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 32 KB | 16 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 1536 B | 1536 B | 1536 B | 1536 B | 1536 B |
| Maximum Clock | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C | -40 C to +85 C | -40 C to +85 C |
| ADC Channels | 5 (10-bit) | 5 (10-bit) | 5 (10-bit) | 5 (10-bit) | 5 (10-bit) |
| Approx. Unit Price (qty 100, as of 2026-09-27) | $5.20 | $4.45 | $6.10 | $5.20 | $6.50 |
Key Differentiators
- Drop-in 32 KB Flash in 28-SOIC at lowest cost (vs PIC18F242-I/SO)
- Extended temperature range available in same 28-SOIC footprint (vs PIC18F252-E/SO)
- Same-die tape-and-reel variant for high-volume assembly (vs PIC18F252T-I/SO)
- Through-hole option with identical silicon (vs PIC18F252-I/SP)
Design Notes
The PIC18F252 requires a stable 4.2-5.5 V VDD supply; place a 100 nF decoupling capacitor as close as physically possible (within 5 mm) to the VDD/VSS pin pair on pin 20/19. Add a 10 uF bulk capacitor at the board entry point, and use a supervisor such as MCP130T or MCP131 to assert a clean reset on brown-out. For battery-powered designs consider the PIC18LF252 variant that supports operation down to 2.0 V. Note: brown-out detect voltage threshold is configurable via configuration bits and should be set above the minimum VDD for the chosen clock frequency (higher MHz requires higher BOR threshold).
When routing the 28-SOIC footprint, use 0.5 mm wide traces for signal lines and a continuous ground pour on the bottom layer connected by multiple vias to a top-side ground copper pour. Keep the MCLR trace short (under 25 mm) and surround it with a ground guard to prevent capacitive coupling that could cause spurious resets. The ICSP programming pins (RB6/PGC and RB7/PGD) need series 10 kohm isolation resistors if shared with application circuitry, otherwise in-circuit programming may load the lines excessively.
A common design pitfall is leaving unused A/D converter channels floating - each unused ANx pin must be tied to either VDD or VSS to prevent shoot-through current and undefined ADC readings. Another pitfall is selecting an oscillator mode that exceeds the configured clock frequency for the VDD voltage; at 40 MHz the PIC18F252 needs VDD >= 4.2 V, and below 3.0 V the F252 cannot run at full speed. Finally, designers forget to disable the WDT (watchdog timer) in code if it is enabled in configuration bits, which causes unexpected resets on long interrupt-disabled routines.
The PIC18F252's analog and digital sections share the same VDD/VSS pins on the 28-SOIC package, so analog traces should be routed away from high-speed digital lines (CCP/PWM outputs, oscillator pins) to minimize ADC noise pickup. Place a small ferrite bead between AVDD and VDD if available, and route the analog reference (VREF+/VREF-) on RA3/RA2 directly from a low-impedance reference such as MCP1501 or MCP1525. Estimated: analog input trace capacitance should remain below 10 pF to preserve ADC acquisition time within the 1.2 us spec for 10-bit accuracy.
Compliance Information
PIC18F252-I/SO is lead-free (Pb-free matte-tin plating) and RoHS compliant per Microchip product page. The standard 'I' industrial temperature grade is not AEC-Q100 qualified; for AEC-Q100 automotive applications, use the PIC18F252-E/SO (extended temperature) or PIC18F252-I/SO with an automotive-grade qualification review.
