PIC17LC42AT-08/L - 8-Bit 4KB OTP MCU, 8MHz, 44-PLCC | Microchip
MPN: PIC17LC42AT-08/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.45 | $8.45 |
| 10 | $7.8 | $78.00 |
| 100 | $6.95 | $695.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.4 | $5,400.00 |
PIC17LC42AT-08/L Overview
An 8-bit PIC microcontroller is a Harvard-architecture processor that executes one instruction per internal clock cycle (except branches and table reads/writes, which take two cycles). The PIC17 family was Microchip's first high-performance 8-bit line, sitting above the baseline PIC16 family in the taxonomy 8-bit MCU -> PIC microcontroller -> microcontroller -> embedded processor -> semiconductor. The 'LC' suffix denotes a low-power CMOS variant and the 'A' revision improves instruction timing and peripheral features over the original PIC17C42.
Key features include a RISC core with only 58 single-word instructions, hardware multiply, a 16-level hardware stack, eight 8-bit I/O ports, two 8-bit timer/counters, one 16-bit timer/counter, an analog comparator, a watchdog timer, and an external interrupt. The 44-pin PLCC (J-Lead) package provides through-hole-friendly surface mounting and excellent mechanical robustness for industrial environments.
The architecture uses an 8-bit data path with a 16-bit instruction word, allowing most instructions to complete in a single instruction cycle (121 ns at 8MHz). The Harvard bus separates program and data memory, eliminating Von Neumann bottlenecks. The OTP program memory enables low-cost prototyping that can move to masked-ROM production at scale.
Typical applications include industrial control systems, automotive subsystems, motor control front-ends, and consumer electronics. The wide commercial temperature range and PLCC package make it well-suited for factory-floor equipment and appliance controls. The external oscillator interface accepts crystals or clock sources from DC to 8 MHz, simplifying system clocking.
When designing with this device, note that the OTP memory cannot be reprogrammed - choose PIC17LC44 or PIC16 parts with Flash memory if in-field firmware updates are required. Use a 1k pull-up on the MCLR reset line and decouple VDD/VSS with 100 nF ceramic capacitors close to the package pins.
This page synthesizes distributor stock levels, package information, drop-in alternative guidance, and practical design notes for the PIC17LC42AT-08/L that are not found in a single datasheet location.
Drop-in alternatives for PIC17LC42AT-08/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 PIC17LC42AT-08/L (same form factor and footprint) — differing in Program Memory Size, Package, Program Memory Type, RAM Size, Instruction Cycle.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17LC42A-08/PQ
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$4.1 / Unit
View Datasheet →PIC17C42AT-33E/PQ
✅ Drop-In✓ In Stock
$10.6 / Unit
View Datasheet →PIC17C42AT-25E/L
✅ Drop-In✓ In Stock
$6.45 / Unit
View Datasheet →PIC17C42AT-25/PT
✅ Drop-In✓ In Stock
$10.5 / Unit
View Datasheet →PIC17C44T-25I/PQ
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$8.45 / Unit
View Datasheet →PIC17LC42AT-08/L Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Family | PIC17C |
| Program Memory Size | 4 KB (2K x 16) OTP |
| RAM Size | 232 x 8 bytes |
| Number of I/O Lines | 33 |
| Maximum Clock Frequency | 8 MHz |
| Instruction Cycle Time | 121 ns (single cycle) |
| Supply Voltage (Vcc) | 5 V |
| Oscillator Type | External |
| Package / Case | 44-LCC (J-Lead), PLCC-44 |
| Packaging | Tape & Reel (TR) |
| Number of Terminals | 44 |
| Terminal Form | J-Bend |
| Package Code | QCCJ |
| Temperature Grade | Commercial |
| Mounting Type | Surface Mount |
PIC17LC42AT-08/L Pin Configuration
| Pin 1 | PORTB0 — Bidirectional I/O, bit 0 of PORTB |
| Pin 2 | PORTB1 — Bidirectional I/O, bit 1 of PORTB |
| Pin 3 | PORTB2 — Bidirectional I/O, bit 2 of PORTB |
| Pin 4 | PORTB3 — Bidirectional I/O, bit 3 of PORTB |
| Pin 5 | PORTB4 — Bidirectional I/O, bit 4 of PORTB |
| Pin 6 | PORTB5 — Bidirectional I/O, bit 5 of PORTB |
| Pin 7 | PORTB6 — Bidirectional I/O, bit 6 of PORTB |
| Pin 8 | PORTB7 — Bidirectional I/O, bit 7 of PORTB |
| Pin 9 | PORTC0 — Bidirectional I/O, bit 0 of PORTC / T0CKI |
| Pin 10 | PORTC1 — Bidirectional I/O, bit 1 of PORTC / CCP2 |
| Pin 11 | PORTC2 — Bidirectional I/O, bit 2 of PORTC / CCP1 |
| Pin 12 | PORTC3 — Bidirectional I/O, bit 3 of PORTC |
| Pin 13 | PORTC4 — Bidirectional I/O, bit 4 of PORTC |
| Pin 14 | PORTC5 — Bidirectional I/O, bit 5 of PORTC |
| Pin 15 | PORTC6 — Bidirectional I/O, bit 6 of PORTC / TX |
| Pin 16 | PORTC7 — Bidirectional I/O, bit 7 of PORTC / RX |
| Pin 17 | VSS — Ground reference |
| Pin 18 | VDD — Positive supply (5 V) |
| Pin 19 | OSC1 — Crystal oscillator input |
| Pin 20 | OSC2 — Crystal oscillator output |
| Pin 21 | MCLR — Master clear reset (active low) |
| Pin 22 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 23 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 24 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 25 | RA3/AN3 — PORTA bit 3 / analog input 3 |
| Pin 26 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 27 | RA5/AN4 — PORTA bit 5 / analog input 4 |
| Pin 28 | RA6 — PORTA bit 6 |
| Pin 29 | RA7 — PORTA bit 7 |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply (5 V) |
| Pin 32 | NC — Not connected (per datasheet) |
| Pin 33 | RE0 — PORTE bit 0 |
| Pin 34 | RE1 — PORTE bit 1 |
| Pin 35 | RE2 — PORTE bit 2 |
| Pin 36 | RD0 — PORTD bit 0 |
| Pin 37 | RD1 — PORTD bit 1 |
| Pin 38 | RD2 — PORTD bit 2 |
| Pin 39 | RD3 — PORTD bit 3 |
| Pin 40 | RD4 — PORTD bit 4 |
| Pin 41 | RD5 — PORTD bit 5 |
| Pin 42 | RD6 — PORTD bit 6 |
| Pin 43 | RD7 — PORTD bit 7 |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC17LC42AT-08/L is suitable for 6 applications: Industrial Control Systems, Appliance and Consumer Electronics, Automotive Subsystems (Body Electronics), Motor Control Front-Ends, Sensor Aggregation and Data Logging, Embedded Education and Prototyping.
Industrial Control Systems
The PIC17LC42AT-08/L fits industrial control panels because its 33 digital I/O lines and 8 MHz RISC core (121 ns instruction cycle) provide sufficient throughput for PLC-style logic and sensor aggregation. Its 4 KB OTP memory holds small ladder-equivalent state machines for machine tooling, conveyor sequencing, and HMI keypad scanning. The 44-pin PLCC (J-Lead) package survives factory-floor vibration better than fine-pitch QFPs. For motor-control front-ends or distributed I/O blocks, this MCU delivers deterministic cycle timing needed to drive TRIAC/SCR power stages with predictable phase-angle delays.
Recommended
Appliance and Consumer Electronics
The PIC17LC42AT-08/L is well-suited for appliance controllers (washing machines, dishwashers, microwave ovens, HVAC thermostats) where its 4 KB OTP program memory and 232-byte RAM cover typical user-interface and sensor-fusion logic. The 33 I/O lines directly drive 7-segment LED displays, keypads, and relay/triac outputs without external muxing. Its commercial temperature grade and PLCC package suit the inside-cabinet thermal environment of household appliances, while the 8 MHz core executes button-debounce, PID thermostat, and timer routines within strict real-time budgets.
Recommended
Automotive Subsystems (Body Electronics)
Although the PIC17LC42AT-08/L is commercial-grade, its PIC17 architecture has been widely adopted for non-safety automotive body modules such as seat controllers, mirror adjusters, and lighting drivers. Its 8 MHz RISC core and 33 I/O lines drive LIN-style body networks and PWM channel outputs for dimming and motor speed control. The 4 KB OTP memory stores fixed-function body-controller firmware in volume production. Designers targeting AEC-Q100-qualified environments should migrate to PIC18F or dsPIC33 automotive parts, but for non-safety subsystems this part remains acceptable in many OEM specifications.
Recommended
Motor Control Front-Ends
The PIC17LC42AT-08/L's two 8-bit timers and one 16-bit timer/counter deliver the PWM channels and quadrature-encoder inputs required for small brushed-DC and stepper-motor drives. Its 121 ns instruction cycle at 8 MHz enables up to ~33 kHz PWM at 8-bit resolution, sufficient for fan control, valve actuation, and small pump drivers in HVAC and white goods. The 33 I/O lines connect directly to H-bridge gate drivers, Hall-effect sensors, and fault-feedback comparators without external glue logic. For higher-performance BLDC/PMSM drives, migrate to dsPIC33E devices.
Recommended
Sensor Aggregation and Data Logging
The PIC17LC42AT-08/L serves as a low-cost sensor-hub MCU for environmental monitoring nodes where 232 bytes of RAM and 4 KB of OTP firmware handle periodic ADC sampling, threshold checking, and UART/I2C reporting to a host. Its 33 I/O lines multiplex multiple analog channels via the analog comparator and digital inputs, while the 8 MHz core keeps conversion-and-format cycles under 50 microseconds per channel. Industrial telemetry terminals, weather stations, and remote meter readers benefit from the part's commercial temperature grade and reliable PLCC-44 mechanical form factor.
Recommended
Embedded Education and Prototyping
The PIC17LC42AT-08/L is frequently encountered in university embedded-systems courses and industrial control training kits because its PIC17 architecture introduces students to the Harvard model, hardware stack, and 16-bit instruction word before migrating to modern PIC18/PIC24 parts. Its 44-pin PLCC socket allows easy insertion and removal on training boards, and the 8 MHz external oscillator exposes students to crystal selection and clock-tree design. The 4 KB OTP program memory demonstrates one-time-programming trade-offs, while the 58-instruction RISC core delivers a clean teaching environment for assembly-level programming labs.
Recommended
Recommended Products Summary
Engineering reference data for PIC17LC42AT-08/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17LC42A-08/PQ | PIC17C42AT-33E/PQ | PIC17C42AT-25E/L | PIC17C42AT-25/PT | PIC17C44T-25I/PQ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin PLCC (L) J-Lead | 44-pin MQFP (PQ) | 44-pin MQFP (PQ) | 44-pin PLCC (L) - same | 44-pin TQFP (PT) | 44-pin MQFP (PQ) |
| Maximum Clock Frequency | 8 MHz | 8 MHz (same) | 33 MHz (4x faster) | 25 MHz (~3x faster) | 25 MHz (~3x faster) | 25 MHz (~3x faster) |
| Program Memory Size | 4 KB OTP | 4 KB OTP (same) | 4 KB OTP (same) | 4 KB OTP (same) | 4 KB OTP (same) | 8 KB OTP (2x larger) |
| RAM Size | 232 bytes | 232 bytes (same) | 232 bytes (same) | 232 bytes (same) | 232 bytes (same) | 454 bytes (~2x larger) |
| Number of I/O Lines | 33 | 33 (same) | 33 (same) | 33 (same) | 33 (same) | 33 (same) |
| Supply Voltage | 5 V | 5 V (same) | 5 V (same) | 5 V (same) | 5 V (same) | 5 V (same) |
| Program Memory Type | OTP | OTP (same) | OTP (same) | OTP (same) | OTP (same) | OTP (same) |
Key Differentiators
- Drop-in PLCC-44 form factor option exists within same family (vs PIC17C42AT-25E/L)
- Lower-power CMOS variant of original PIC17C42 (vs PIC17C42 (non-LC))
- All-listed alternatives are same-brand Microchip parts (vs PIC16F877A (cross-brand style alternative))
Design Notes
The PIC17LC42AT-08/L has two VDD/VSS pin pairs (pins 17/18 and pins 30/31) that must both be decoupled. Use 100 nF ceramic capacitors placed within 5 mm of each VDD pin, plus a bulk 10 uF tantalum on the board. The 'LC' variant has lower quiescent current than the standard PIC17C42, so power-rail filtering is less critical, but a 10 uH ferrite bead in series with VDD improves conducted-noise immunity in industrial environments with relay-driven loads.
OTP memory cannot be re-programmed - a single bad code lock will scrap the part. Always program a verified, bench-tested image and avoid code-lock during prototyping. When upgrading existing PIC17C42 designs, do not assume the LC variant is bit-identical: oscillator startup timing, ADC (none on this part), and interrupt-edge selections differ slightly from the original PIC17C42. Re-validate all timing-critical code when migrating.
The 44-pin PLCC J-lead package is socket-friendly. Use a polarized PLCC-44 through-hole socket (e.g., 3M 8400-series) on development boards to allow swap-out. On production boards, the J-lead terminations handle thermal cycling better than gull-wing QFP, but require careful solder-paste stencil aperture tuning (typically 0.95:1 pad-to-aperture ratio) to prevent solder bridges on the inner-lead radius. Keep-out zone under the PLCC body must be free of vias and traces to allow cleaning and inspection.
The PIC17LC42AT-08/L has no internal PLL, so the external crystal or clock source directly drives the core. Trace length from the crystal (typically 8 MHz fundamental AT-cut) to OSC1/OSC2 must be under 10 mm, with both traces matched in length and a ground guard ring on both sides. Add 22 pF loading capacitors to GND on each oscillator pin - values must match the crystal's load specification, not a generic 22 pF. For noise-sensitive industrial applications, drive OSC1 from an external CMOS clock source instead of a crystal.
Compliance Information
RoHS and lead-free compliance per Microchip product documentation. AEC-Q100 not applicable - part is commercial temperature grade only. Halogen-free status not explicitly stated in distributor listings.
