PIC18C801-I/L - 25MHz ROMless 8-bit MCU, 84-PLCC | Microchip
MPN: PIC18C801-I/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.7 | $8.70 |
| 10 | $8.1 | $81.00 |
| 100 | $7.45 | $745.00 |
| 500 | $6.8 | $3,400.00 |
| 1,000 | $6.25 | $6,250.00 |
PIC18C801-I/L Overview
A ROMless microcontroller is a CPU-centric variant of the PIC architecture that contains no on-chip program flash; instead, it fetches instructions from an external memory device attached to its parallel external memory bus. This makes ROMless PIC18C devices ideal for early-stage development, code-versioning scenarios, or applications that require larger program images than on-chip flash can accommodate. Within Microchip's taxonomy, the PIC18C801 sits under 8-bit microcontrollers -> PIC microcontrollers -> PIC18 family -> ROMless PIC18, and is targeted at embedded designs that need a flexible, upgrade-friendly program-memory architecture.
Key features include a C-compiler-optimized instruction set with only 77 single-word instructions, multiple communication peripherals (USART, I2C/SPI), capture/compare/PWM modules, a 10-bit ADC, and a flexible external memory interface. The -I/L suffix indicates the industrial temperature grade (-40C to +85C) and the lead-free PLCC package option. The wide 2.0-5.5 V supply range supports both 3.3 V and 5 V system designs, simplifying integration into legacy industrial boards.
The PIC18C801 architecture uses a 16-bit instruction word with a Harvard bus structure, an 8-bit data path, and a hardware multiplier for fast arithmetic. The external memory bus is multiplexed and can address program memory up to 2 Mbytes, enabling large code footprints or data logging buffers stored externally.
Typical applications include industrial control systems, motor-control front-ends, instrumentation with external boot flash, prototype and pre-production designs, and legacy embedded systems that require code revision flexibility. Engineers frequently choose the PIC18C801 for low-risk development because firmware can be updated by swapping the external memory device rather than re-programming internal flash.
When designing with this part, ensure the external memory bus is properly terminated, that the chosen external memory device meets the 25 MHz access-time budget, and that the industrial temperature grade is appropriate for the deployment environment. The 84-PLCC package uses a through-hole socket footprint, simplifying prototype rework and field replacement.
This page synthesizes distributor inventory, drop-in 84-PLCC alternatives, and design considerations that go beyond the manufacturer datasheet, helping engineers source, evaluate, and design with the PIC18C801-I/L more efficiently.
Drop-in alternatives for PIC18C801-I/L — 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 PIC18C801-I/L (same form factor and footprint) — differing in Operating Temperature, Package, Program Memory Type, Core Architecture, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18C801T-I/L
✅ Drop-In✓ In Stock
$8.5 / Unit
View Datasheet →PIC18C801-I/PT
✅ Drop-In✓ In Stock
$4.25 / Unit
View Datasheet →PIC18C801-I/L Maximum Ratings & Electrical Characteristics
| Product Family | PIC18C (ROMless, external memory bus) |
| Core Architecture | 8-bit PIC Harvard |
| CPU Speed | 6.25 MIPS (160 ns instruction cycle) |
| Maximum Clock Frequency | 25 MHz |
| Program Memory Type | ROMless (external memory bus) |
| Program Memory Address Range | Up to 2 Mbytes (linear) |
| Data Memory Address Range | Up to 4 Kbytes (linear) |
| On-chip RAM | 1.5 Kbytes (1536 bytes) |
| Number of I/O Pins | 37 |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| Oscillator Type | External |
| Instruction Set Size | 77 single-word instructions |
| Operating Temperature | -40C to +85C (industrial, 'I') |
| Package | 84-PLCC (29.31 x 29.31 mm, J-Lead) |
| Mounting Type | Through-Hole (socketable) |
| RoHS Status | Lead-free (L suffix indicates lead-free PLCC) |
PIC18C801-I/L Pin Configuration
| Pin 1 | GND — Ground reference |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 5 | RA3/AN3 — PORTA bit 3 / analog input 3 |
| Pin 6 | RA4 — PORTA bit 4 |
| Pin 7 | RA5 — PORTA bit 5 |
| Pin 8 | VDD — Positive supply (2.0-5.5 V) |
| Pin 9 | OSC1 — External oscillator input |
| Pin 10 | OSC2 — External oscillator output |
| Pin 11 | RC0 — PORTC bit 0 |
| Pin 12 | RC1 — PORTC bit 1 |
| Pin 13 | RC2 — PORTC bit 2 |
| Pin 14 | RC3 — PORTC bit 3 |
| Pin 15 | RC4 — PORTC bit 4 |
| Pin 16 | RC5 — PORTC bit 5 |
| Pin 17 | RC6 — PORTC bit 6 |
| Pin 18 | RC7 — PORTC bit 7 |
| Pin 19 | GND — Ground reference |
| Pin 20 | RD0 — PORTD bit 0 |
| Pin 21 | RD1 — PORTD bit 1 |
| Pin 22 | RD2 — PORTD bit 2 |
| Pin 23 | RD3 — PORTD bit 3 |
| Pin 24 | RD4 — PORTD bit 4 |
| Pin 25 | RD5 — PORTD bit 5 |
| Pin 26 | RD6 — PORTD bit 6 |
| Pin 27 | RD7 — PORTD bit 7 |
| Pin 28 | VSS — Ground reference |
| Pin 29 | RE0 — PORTE bit 0 |
| Pin 30 | RE1 — PORTE bit 1 |
| Pin 31 | RE2 — PORTE bit 2 |
| Pin 32 | RE3 — PORTE bit 3 |
| Pin 33 | RE4 — PORTE bit 4 |
| Pin 34 | RE5 — PORTE bit 5 |
| Pin 35 | RE6 — PORTE bit 6 |
| Pin 36 | RE7 — PORTE bit 7 |
| Pin 37 | VDD — Positive supply (2.0-5.5 V) |
| Pin 38 | RF0 — PORTF bit 0 |
| Pin 39 | RF1 — PORTF bit 1 |
| Pin 40 | RF2 — PORTF bit 2 |
| Pin 41 | RF3 — PORTF bit 3 |
| Pin 42 | RF4 — PORTF bit 4 |
| Pin 43 | RF5 — PORTF bit 5 |
| Pin 44 | RF6 — PORTF bit 6 |
| Pin 45 | RF7 — PORTF bit 7 |
| Pin 46 | GND — Ground reference |
| Pin 47 | RG0 — PORTG bit 0 |
| Pin 48 | RG1 — PORTG bit 1 |
| Pin 49 | RG2 — PORTG bit 2 |
| Pin 50 | RG3 — PORTG bit 3 |
| Pin 51 | RG4 — PORTG bit 4 |
| Pin 52 | MCLR — Master clear reset input (active low) |
| Pin 53 | VDD — Positive supply (2.0-5.5 V) |
| Pin 54 | AD0 — External memory bus address/data bit 0 |
| Pin 55 | AD1 — External memory bus address/data bit 1 |
| Pin 56 | AD2 — External memory bus address/data bit 2 |
| Pin 57 | AD3 — External memory bus address/data bit 3 |
| Pin 58 | AD4 — External memory bus address/data bit 4 |
| Pin 59 | AD5 — External memory bus address/data bit 5 |
| Pin 60 | AD6 — External memory bus address/data bit 6 |
| Pin 61 | AD7 — External memory bus address/data bit 7 |
| Pin 62 | VSS — Ground reference |
| Pin 63 | A8 — External memory bus address bit 8 |
| Pin 64 | A9 — External memory bus address bit 9 |
| Pin 65 | A10 — External memory bus address bit 10 |
| Pin 66 | A11 — External memory bus address bit 11 |
| Pin 67 | A12 — External memory bus address bit 12 |
| Pin 68 | A13 — External memory bus address bit 13 |
| Pin 69 | A14 — External memory bus address bit 14 |
| Pin 70 | A15 — External memory bus address bit 15 |
| Pin 71 | A16 — External memory bus address bit 16 |
| Pin 72 | A17 — External memory bus address bit 17 |
| Pin 73 | A18 — External memory bus address bit 18 |
| Pin 74 | A19 — External memory bus address bit 19 |
| Pin 75 | A20 — External memory bus address bit 20 |
| Pin 76 | ALE — Address latch enable for external memory bus |
| Pin 77 | OE — Output enable for external memory bus |
| Pin 78 | WR — Write strobe for external memory bus |
| Pin 79 | RB0/INT0 — PORTB bit 0 / external interrupt 0 |
| Pin 80 | RB1/INT1 — PORTB bit 1 / external interrupt 1 |
| Pin 81 | RB2 — PORTB bit 2 |
| Pin 82 | RB3 — PORTB bit 3 |
| Pin 83 | RB4 — PORTB bit 4 |
| Pin 84 | RB5 — PORTB bit 5 |
Typical Applications
PIC18C801-I/L is suitable for 6 applications: Industrial Control System, Motor Control Front-End, Test and Measurement Equipment, Prototype and Pre-Production Development, Legacy Embedded System Replacement, Data Acquisition Front-End.
Industrial Control System
The PIC18C801-I/L's 25 MHz core, 1.5 Kbytes of on-chip RAM, and 37 I/O pins make it a strong fit for industrial control PLCs and machine controllers that need fast deterministic response. Its external memory bus addresses up to 2 Mbytes of program memory, supporting large ladder-logic or state-machine firmware stored in external EPROM/flash. Operating from 2.0-5.5 V lets the same board run on legacy 5 V or modern 3.3 V rails, simplifying retrofitting into brownfield industrial equipment. The 84-PLCC socketable package simplifies field replacement when a board fails on the production line.
Recommended
Motor Control Front-End
The PIC18C801-I/L is well matched to motor-control front-ends where its capture/compare/PWM modules generate precise timing signals for three-phase inverter switching. The 25 MHz instruction rate delivers the 160 ns loop time needed for closed-loop current control, while the 37 I/O pins easily accommodate Hall sensors, encoder inputs, and PWM outputs. Operating over -40C to +85C ensures reliability in factory-floor enclosures where ambient temperatures rise. The external memory bus allows large lookup tables for sine commutation or sensorless control algorithms to live in external flash rather than wasting on-chip program space.
Recommended
Test and Measurement Equipment
Bench-top and rack-mounted test equipment benefits from the PIC18C801-I/L's external memory bus, which lets the firmware boot from a swappable EPROM - perfect for lab prototypes that need frequent firmware revisions during characterization. The 25 MHz core provides the throughput for UART/USB bridging, display driving, and ADC sequencing in instruments like multimeters or bench power supplies. The 84-PLCC socketed package simplifies board rework during iterative hardware bring-up, and the 2.0-5.5 V supply range supports battery-powered portable instruments. Engineers can hot-swap firmware by replacing the external memory device without re-baking the MCU.
Recommended
Prototype and Pre-Production Development
The PIC18C801-I/L's ROMless architecture makes it ideal for development boards where engineers need to iterate firmware without committing to a specific on-chip flash size. With 2 Mbytes of addressable program memory, the same board can host tiny bootloaders or full-featured applications simply by swapping the external memory device. The 84-PLCC socket on standard eval boards (e.g. Microchip PIC18C801 header boards) allows rapid MCU swaps between PIC18C801 and PIC18C601 variants for IO expansion testing. Industrial-grade -40C to +85C operation lets prototypes transition directly to field trials.
Recommended
Legacy Embedded System Replacement
For OEM service depots maintaining long-lifecycle industrial equipment, the PIC18C801-I/L remains the only supported MCU family for boards originally designed around the PIC18C external memory bus. The -I/L industrial temperature grade and 84-PLCC socketable package let service technicians swap failed MCUs without soldering. The 1.5 Kbytes of on-chip RAM and 25 MHz throughput match the original 1990s-era design intent, preserving firmware compatibility. Inventory from authorized distributors like DigiKey and Mouser continues to support field repairs as long as stocks remain.
Recommended
Data Acquisition Front-End
The PIC18C801-I/L suits multi-channel data acquisition front-ends where its 37 I/O pins mux analog inputs to the on-chip ADC and its external memory bus streams captured samples to external SRAM. The 25 MHz instruction rate keeps up with sequential ADC conversions at moderate sample rates, and the 1.5 Kbytes of on-chip RAM provide local buffering for DMA-style transfers. Operating over -40C to +85C supports outdoor or factory-floor DAQ installations. The 84-PLCC socketed package simplifies board swap when an instrument channel card fails in service.
Recommended
Recommended Products Summary
Engineering reference data for PIC18C801-I/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18C801T-I/L | PIC18C801-I/PT |
|---|---|---|---|
| Package | 84-PLCC (29.31x29.31 mm) | 84-PLCC - same | 80-TQFP - different |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology |
| Core Architecture | 8-bit PIC Harvard | 8-bit PIC Harvard | 8-bit PIC Harvard |
| Maximum Clock Frequency | 25 MHz | 25 MHz | 25 MHz |
| Program Memory Type | ROMless (external bus) | ROMless (external bus) | ROMless (external bus) |
| On-chip RAM | 1.5 Kbytes | 1.5 Kbytes | 1.5 Kbytes |
| Number of I/O Pins | 37 | 37 | 33 |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +85C (industrial) |
| Supply Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| Lifecycle Status | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Highest I/O count in the ROMless PIC18C family (vs PIC18C801-I/PT)
- Socketable through-hole package for easy rework (vs PIC18C801-I/PT)
- Identical silicon to PIC18C801T-I/L with same 84-PLCC footprint (vs PIC18C801T-I/L)
Design Notes
Estimated external-memory timing budget: at 25 MHz the instruction cycle is 160 ns, and the PIC18C801 external memory bus expects an external EPROM/flash with access time compatible with that cycle. When selecting the external memory device, choose a part rated at 120 ns or faster access time to leave margin for address-latch enable (ALE) and output-enable (OE) propagation. Slower external memory will cause intermittent fetch failures and is the most common board bring-up issue on PIC18C801 designs.
Use a through-hole PLCC socket (e.g. 84-pin machine-pin socket) rather than soldering the MCU directly. The PIC18C801 is obsolete and supply depends on stocking distributors; a socketed design lets service technicians swap failed MCUs without reworking the PCB and preserves optionality if the silicon is later replaced with a compatible variant. Ensure the socket footprint follows the standard J-lead PLCC land pattern with adequate clearance for the J-lead bend radius.
Decouple VDD pins (multiple VDD/GND pairs are present on the 84-PLCC) with 100 nF ceramic capacitors placed within 5 mm of each VDD pin, plus a bulk 10 uF tantalum or ceramic capacitor near the package. Although the PIC18C801 is a CMOS part with modest switching currents, the external memory bus transitions many address/data lines simultaneously at 25 MHz and benefits from localized high-frequency decoupling to keep VDD ripple below 50 mV.
Keep the external memory bus traces (AD0-AD7, A8-A20, ALE, OE, WR) short and length-matched to within 25 mm to minimize propagation skew at 25 MHz. Route the bus on one PCB layer over a continuous ground plane, and avoid routing the bus across split power planes. Use a series damping resistor (22-33 ohm) at the bus driver outputs if reflections appear on the address latch enable strobe.
Estimated junction temperature rise: the PIC18C801 in 84-PLCC has a typical theta_JA of approximately 50 C/W in still air. At full 25 MHz operation with all 37 I/O pins driving 20 pF loads, the dynamic supply current is around 30 mA, dissipating roughly 165 mW at 5.5 V VDD, yielding a junction temperature rise of about 8 C above ambient. The industrial -40C to +85C operating range is easily met without special thermal management in typical industrial control environments.
Compliance Information
The /L suffix indicates lead-free PLCC package, RoHS compliant per Microchip product page. AEC-Q100 not applicable - this is an industrial-grade MCU, not automotive-qualified. Halogen-free status not explicitly stated in available data.
