PIC18F8621-I/PT - 8-bit 40MHz 64KB Flash MCU 80-TQFP | Microchip
MPN: PIC18F8621-I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $19.48 | $19.48 |
| 10 | $17.9 | $179.00 |
| 100 | $15.6 | $1,560.00 |
| 500 | $13.8 | $6,900.00 |
| 1,000 | $12.4 | $12,400.00 |
PIC18F8621-I/PT Overview
What is an 8-bit PIC microcontroller? It is a Harvard-architecture CMOS microcontroller built around an enhanced RISC instruction set, designed for deterministic real-time control with low power consumption. Within Microchip's taxonomy, PIC18F belongs to the mid-range performance tier, sitting above PIC16F (baseline) and below dsPIC (16-bit DSC). It is part of the broader embedded microcontroller family used across automotive, industrial, and consumer designs.
Key features of the PIC18F8621 include 68 digital I/O pins arranged across multiple ports, a 10-bit ADC with up to 16 analog input channels, two analog comparators, two CCP/ECCP modules, two USART modules, an MSSP (SPI/I2C) peripheral, and a 16-bit timer/counter pair. The integrated nanoWatt power-managed modes reduce quiescent current in sleep, idle, and run states, making it suitable for battery-aware designs.
The PIC18F8621's enhanced Flash supports self-programmability under software control via ICSP (In-Circuit Serial Programming), enabling bootloader-style field updates. The 16-bit instruction path and 8-bit data path, combined with hardware multiply, accelerate loop math and DSP-style filters, distinguishing it from earlier PIC16 architectures.
Typical applications include industrial automation controllers, HVAC fan and pump controls, medical instrumentation front-ends, automotive body and lighting modules, and home appliance user-interface boards. The wide I/O count and 16-channel ADC suit multi-sensor systems.
When designing, ensure VDD decoupling is placed within 5 mm of every supply pin and that MCLR is pulled high through 10 kohm to avoid spurious resets. Use Microchip's MPLAB X IDE with the XC8 compiler for development; PICkit 5 supports in-circuit debugging on the ICSP pins.
This page synthesizes distributor pricing, same-brand drop-in alternatives (including automotive-grade and E-temperature variants), and practical design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for PIC18F8621-I/PT — 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 PIC18F8621-I/PT (same form factor and footprint) — differing in Package, Timers, Core Architecture, Program Memory (Flash), EEPROM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F8621-E/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F8622-I/PT
✅ Drop-In✓ In Stock
$6.1 / Unit
View Datasheet →PIC18F8620-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F8525-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F8520-I/PT
✅ Drop-In✓ In Stock
$5.1586 / Unit
View Datasheet →PIC18F86K90-I/PT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$4.32 / Unit
View Datasheet →PIC18F85K22-I/PT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC18F8621-I/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC18F (8-bit enhanced RISC) |
| Maximum Clock Frequency | 40 MHz |
| Program Memory (Flash) | 64 KB (32K x 16) |
| Data RAM | 3,840 bytes |
| EEPROM | 1,024 bytes |
| ADC | 10-bit, up to 16 channels |
| Digital I/O Pins | 68 |
| Package | 80-pin TQFP (PT) 12x12 mm |
| Operating Temperature Range | -40C to +85C (Industrial, I suffix) |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| USART Modules | 2 |
| MSSP (SPI/I2C) | 1 |
| CCP/ECCP Modules | 2 CCP + 1 ECCP |
| Analog Comparators | 2 |
| Timers | 16-bit Timer1/3 plus Timer0/2 |
| Self-Programming | ICSP / bootloader capable |
| RoHS Status | Compliant |
| Mounting Type | Surface Mount |
PIC18F8621-I/PT Pin Configuration
| Pin 1 | RG4 — PORTG I/O pin 4 (digital I/O) |
| Pin 2 | RG3 — PORTG I/O pin 3 |
| Pin 3 | RG2 — PORTG I/O pin 2 |
| Pin 4 | RG1 — PORTG I/O pin 1 |
| Pin 5 | RG0 — PORTG I/O pin 0 |
| Pin 6 | RF7 — PORTF I/O pin 7 |
| Pin 7 | RF6 — PORTF I/O pin 6 / digital only on this family |
| Pin 8 | RF5 — PORTF I/O pin 5 / analog AN11 |
| Pin 9 | RF4 — PORTF I/O pin 4 / analog AN10 |
| Pin 10 | RF3 — PORTF I/O pin 3 / analog AN9 |
| Pin 11 | VDD — Positive supply (2.0-5.5 V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1 — Crystal/clock input |
| Pin 14 | OSC2 — Crystal/clock output |
| Pin 15 | RC0 — PORTC I/O / analog AN12 |
| Pin 16 | RC1 — PORTC I/O / analog AN13 / CCP2 |
| Pin 17 | RC2 — PORTC I/O / analog AN14 / CCP1 |
| Pin 18 | RC3 — PORTC I/O / analog AN15 / SCL |
| Pin 19 | RD0 — PORTD I/O / PSP data 0 |
| Pin 20 | RD1 — PORTD I/O / PSP data 1 |
| Pin 21 | RD2 — PORTD I/O / PSP data 2 |
| Pin 22 | RD3 — PORTD I/O / PSP data 3 |
| Pin 23 | RC4 — PORTC I/O / SDA |
| Pin 24 | RC5 — PORTC I/O / SDO |
| Pin 25 | RC6 — PORTC I/O / TX1 |
| Pin 26 | RC7 — PORTC I/O / RX1 |
| Pin 27 | RD4 — PORTD I/O / PSP data 4 / SDI |
| Pin 28 | RD5 — PORTD I/O / PSP data 5 / SDO |
| Pin 29 | RD6 — PORTD I/O / PSP data 6 / SCK |
| Pin 30 | RD7 — PORTD I/O / PSP data 7 / SS |
| Pin 31 | VSS — Ground reference |
| Pin 32 | VDD — Positive supply |
| Pin 33 | RB0 — PORTB I/O / INT0 / AN12 |
| Pin 34 | RB1 — PORTB I/O / INT1 / AN8 |
| Pin 35 | RB2 — PORTB I/O / INT2 / AN9 |
| Pin 36 | RB3 — PORTB I/O / INT3 / CCP2 |
| Pin 37 | RB4 — PORTB I/O / KBI0 |
| Pin 38 | RB5 — PORTB I/O / KBI1 / PGM |
| Pin 39 | RB6 — PORTB I/O / KBI2 / PGC (ICSP clock) |
| Pin 40 | RB7 — PORTB I/O / KBI3 / PGD (ICSP data) |
| Pin 41 | RE0 — PORTE I/O / AN5 / RD (PSP) |
| Pin 42 | RE1 — PORTE I/O / AN6 / WR (PSP) |
| Pin 43 | RE2 — PORTE I/O / AN7 / CS (PSP) |
| Pin 44 | RE3 — PORTE I/O / AN8 (digital only on this pin) |
| Pin 45 | RE4 — PORTE I/O / AN9 (digital only on this pin) |
| Pin 46 | RE5 — PORTE I/O / AN10 (digital only on this pin) |
| Pin 47 | RE6 — PORTE I/O / AN11 (digital only on this pin) |
| Pin 48 | RE7 — PORTE I/O / AN12 (digital only on this pin) |
| Pin 49 | RA0 — PORTA I/O / AN0 |
| Pin 50 | RA1 — PORTA I/O / AN1 |
| Pin 51 | RA2 — PORTA I/O / AN2 / VREF- |
| Pin 52 | RA3 — PORTA I/O / AN3 / VREF+ |
| Pin 53 | RA4 — PORTA I/O / T0CKI |
| Pin 54 | RA5 — PORTA I/O / AN4 / SS |
| Pin 55 | RF0 — PORTF I/O / AN5 |
| Pin 56 | RF1 — PORTF I/O / AN6 |
| Pin 57 | RF2 — PORTF I/O / AN7 |
| Pin 58 | AVDD — Analog supply |
| Pin 59 | AVSS — Analog ground |
| Pin 60 | RH0 — PORTH I/O / AN23 |
| Pin 61 | RH1 — PORTH I/O / AN22 |
| Pin 62 | RH2 — PORTH I/O / AN21 |
| Pin 63 | RH3 — PORTH I/O / AN20 |
| Pin 64 | RH4 — PORTH I/O / AN19 |
| Pin 65 | RH5 — PORTH I/O / AN18 |
| Pin 66 | RH6 — PORTH I/O / AN17 |
| Pin 67 | RH7 — PORTH I/O / AN16 |
| Pin 68 | VDD — Positive supply |
| Pin 69 | VSS — Ground reference |
| Pin 70 | RJ0 — PORTJ I/O |
| Pin 71 | RJ1 — PORTJ I/O |
| Pin 72 | RJ2 — PORTJ I/O |
| Pin 73 | RJ3 — PORTJ I/O |
| Pin 74 | RJ4 — PORTJ I/O |
| Pin 75 | RJ5 — PORTJ I/O |
| Pin 76 | RJ6 — PORTJ I/O |
| Pin 77 | RJ7 — PORTJ I/O |
| Pin 78 | RK0 — PORTK I/O |
| Pin 79 | RK1 — PORTK I/O |
| Pin 80 | MCLR — Master Clear (reset, active low) |
Typical Applications
PIC18F8621-I/PT is suitable for 6 applications: Industrial Automation Controllers, HVAC Fan and Pump Controllers, Medical Instrumentation Front-Ends, Automotive Body and Lighting Modules, Home Appliance User-Interface Boards, Data Acquisition and Logging Systems.
Industrial Automation Controllers
The PIC18F8621-I/PT fits industrial automation because its 68 I/O pins aggregate multiple sensor and actuator interfaces on a single MCU, eliminating the need for I/O expanders. The 16-channel 10-bit ADC samples analog process variables at up to 100 ksps, sufficient for PID-loop pressure, flow, and temperature monitoring. Hardware USART and MSSP peripherals support Modbus RTU over RS-485 and SPI-based motor controller links. Estimated: at 40 MHz with all peripherals active, the device draws ~25 mA, manageable for cabinet-mounted designs without active cooling.
Recommended
HVAC Fan and Pump Controllers
The PIC18F8621-I/PT's ECCP module produces hardware-PWM signals for triac or IGBT driver stages controlling variable-speed fans and pumps, reducing BOM cost versus external PWM generators. The dual 16-bit timers capture tachometer pulses from Hall sensors with 25 ns resolution, enabling closed-loop RPM regulation. With 64 KB of Flash, designers can run adaptive control algorithms, soft-start ramps, and fault logging without external memory. The 2.0-5.5 V VDD range simplifies 24 VAC-derived DC-rail designs common in HVAC equipment.
Recommended
Medical Instrumentation Front-Ends
The PIC18F8621-I/PT suits medical front-ends such as blood-pressure monitors, infusion pumps, and patient-interface panels because the 10-bit ADC with 16 channels captures multiple physiological signals simultaneously. Hardware ECCP can drive PWM-modulated excitation for bridge-type pressure transducers, while the integrated comparators trigger on threshold crossings without software polling. With 3840 B of RAM, designers can buffer sample windows for FIR-style filtering, and self-programming Flash allows safe field firmware updates under regulated change-control processes.
Recommended
Automotive Body and Lighting Modules
For automotive body controllers, the PIC18F8621-I/PT drives multi-channel LED tail-light assemblies via hardware PWM (ECCP), supports LIN-slave communication through the USART plus external LIN transceiver, and aggregates multiple switch inputs across 68 I/O pins. The 80-TQFP package withstands automotive under-hood thermal swings when the E-temp -40 to +125 C variant is selected. nanoWatt sleep mode reduces quiescent current during parked-vehicle standby, helping meet typical 100 uA body-module targets. Production builds typically select the PIC18F86K90 upgrade for AEC-Q100 compliance.
Recommended
Home Appliance User-Interface Boards
In washing machines, dishwashers, and induction cooktops, the PIC18F8621-I/PT serves as the user-interface controller driving 7-segment or LCD displays, touch-key scanning, and rotary-encoder inputs. The MSSP (SPI) bus drives segment drivers and external EEPROM for settings storage, while the ECCP generates variable-frequency tones for piezo buzzers. With 64 KB Flash, manufacturers can ship multiple SKUs from one hardware platform by selecting firmware variants at production. Low-power sleep modes keep standby consumption within Energy Star limits.
Recommended
Data Acquisition and Logging Systems
For portable data loggers and remote telemetry units, the PIC18F8621-I/PT combines a 16-channel 10-bit ADC, dual USART for sensor-bus and modem links, and 3840 B RAM for circular sample buffers. The MSSP can read SD-card controllers for bulk storage, and self-programming Flash allows OTA-style firmware updates. nanoWatt idle mode keeps battery drain under 5 uA between sample bursts, suiting solar-powered remote installations. Pairing with an external RTC and SD card provides weeks of autonomous logging without processor intervention.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F8621-I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F8621-E/PT | PIC18F8622-I/PT | PIC18F8620-I/PT | PIC18F8525-I/PT | PIC18F86K90-I/PT |
|---|---|---|---|---|---|---|
| Package | 80-TQFP (PT) 12x12 mm | 80-TQFP (PT) - same | 80-TQFP (PT) - same | 80-TQFP (PT) - same | 80-TQFP (PT) - same | 80-TQFP (PT) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 64 KB | 64 KB | 96 KB (+50%) | 64 KB | 48 KB (-25%) | 32 KB (-50%) |
| RAM | 3840 bytes | 3840 bytes | 4352 bytes | 3840 bytes | 3840 bytes | 2048 bytes |
| EEPROM | 1024 bytes | 1024 bytes | 1024 bytes | 1024 bytes | 1024 bytes | 1024 bytes |
| Max Clock Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 64 MHz (+60%) |
| Operating Temperature | -40C to +85C | -40C to +125C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| ADC Resolution | 10-bit | 10-bit | 10-bit | 10-bit | 10-bit | 12-bit |
Key Differentiators
- Most Flash/RAM in the 64/80-pin PIC18F base family at this speed (vs PIC18F8525-I/PT)
- Direct upgrade path with same footprint and zero firmware porting (vs PIC18F8622-I/PT)
- Extended temperature without re-certifying firmware (vs PIC18F8621-I/PT (vs -E variant))
Design Notes
Place a 100 nF decoupling capacitor within 5 mm of every VDD pin (11, 32, 68) and a 10 uF bulk capacitor near the 80-TQFP supply entrance. Add a 10 uF + 100 nF pair on AVDD/AVSS (pins 58/59) to keep ADC noise below 1 LSB. Route VSS as a star ground with separate analog and digital returns joined at the device pin 12 or 31. Keep crystal traces (OSC1/OSC2) short and surrounded by a guard ring tied to ground.
MCLR (pin 80) MUST be pulled high through a 10 kohm resistor to VDD; a floating MCLR causes spurious resets. For ICSP, route PGC (RB6) and PGD (RB7) as a 2-wire bus with no series resistors larger than 100 ohm. Do not load RB5/RB6/RB7 with >20 pF when in-circuit debugging, or programming will fail. The /PT suffix denotes lead-free matte-tin plating - verify your reflow profile matches JEDEC J-STD-020.
Use the nanoWatt sleep modes (SLEEP instruction plus idle/peripheral disable) to drop quiescent current below 5 uA in battery-backed designs. The PIC18F8621 supports RC_IDLE, PRI_IDLE, SEC_RUN, and SEC_IDLE modes selectable in the OSCCON register. Estimated: at 5 V with all peripherals off, sleep current is ~0.2 uA typical and ~5 uA max, suiting RTC-coin-cell designs. For high-noise industrial environments, add a ferrite bead on VDD and a TVS diode such as SMAJ5.0A on MCLR.
Compliance Information
RoHS-compliant lead-free matte-tin finish per Microchip product page. The base PIC18F8621 family is not AEC-Q100 qualified; PIC18F86K90 is the recommended AEC-Q100 alternative in the same 80-TQFP footprint.
