PIC17LC42A-08/P - 8MHz 4KB OTP 8-bit MCU | Microchip | 40-DIP
MPN: PIC17LC42A-08/P ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $14.5 | $14.50 |
| 10 | $12.95 | $129.50 |
| 100 | $11.4 | $1,140.00 |
| 500 | $10.25 | $5,125.00 |
| 1,000 | $9.1 | $9,100.00 |
PIC17LC42A-08/P Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program and data memory, and programmable I/O peripherals. The PIC17C/LC family is the high-end 8-bit tier of Microchip's PIC architecture, positioned between the PIC16 mid-range family and the original PIC18 family, with an enhanced 16-bit instruction word that allows single-cycle execution on most opcodes. The 'LC' suffix indicates the low-power CMOS variant; the 'A' marks the silicon revision described in the PIC17C4X datasheet (DS30412C). All PIC17 devices share an orthogonal instruction set of 58 single-word instructions to learn, making firmware portable across the family.
Key features of the PIC17LC42A-08/P include 33 programmable digital I/O lines arranged across multiple ports, an 8-bit data path with a 16-bit-wide program word, support for external oscillator operation, and the through-hole 40-pin PDIP footprint that simplifies prototyping and breadboard use. The device operates from a 5V supply, with the 'LC' sub-family specifically targeting low-power applications. The instruction cycle of 121 ns at 33 MHz makes it well suited to real-time control loops where deterministic single-cycle execution is required.
Typical applications include industrial control logic, motor drive sequencing, instrumentation front-ends, and legacy embedded systems where the PIC17 instruction set is already established in firmware. The 4KB OTP program memory and 232 bytes of RAM are sufficient for moderate-complexity control tasks, while the 33 I/O pins permit direct interfacing to keypads, displays, and analog signal conditioning circuitry without external glue logic.
When designing with this part, designers should note that PIC17C/LC devices require Microchip's legacy development tools (MPLAB IDE v5.x or earlier, or MPLAB X with legacy compiler support). The 40-pin PDIP package consumes significant board space versus modern QFP alternatives; consider migrating to PIC18F or dsPIC33 families only if firmware portability and supply continuity permit. Verify OTP programming window timing against your programmer's spec - some legacy PIC17 parts have short programming windows that require batch programming.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, providing engineering context beyond what the DS30412C data sheet offers.
Drop-in alternatives for PIC17LC42A-08/P — 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 PIC17LC42A-08/P (same form factor and footprint) — differing in Program Memory Size, Maximum Clock Frequency, Package, Mounting Type, RAM Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17LC42A-08/PQ
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC17C42A-08/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17LC44-08/P
✅ Drop-In✓ In Stock
$6.95 / Unit
View Datasheet →PIC17LC42A-08I/P
✅ Drop-In✓ In Stock
$3.75 / Unit
View Datasheet →PIC17C42A-16/P
✅ Drop-In✓ In Stock
$7.45 / Unit
View Datasheet →PIC17LC42A-08/P Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Series | PIC17C/LC (high-performance 8-bit CMOS EPROM/ROM) |
| Program Memory Size | 4 KB (2K x 16) OTP EPROM |
| RAM Size | 232 x 8 bytes |
| Number of I/O Pins | 33 |
| Maximum Clock Frequency | 33 MHz (input) |
| Instruction Cycle | 121 ns (single-cycle) |
| Number of Instructions | 58 single-word |
| Oscillator Type | External |
| Supply Voltage | 5 V |
| Package / Case | 40-DIP (0.600", 15.24 mm) |
| Mounting Type | Through-Hole |
| Packaging | Tube |
PIC17LC42A-08/P Pin Configuration
| Pin 1 | RA0/AN0 — Port A bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 — Port A bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 — Port A bit 2 / analog input 2 |
| Pin 4 | RA3/AN3 — Port A bit 3 / analog input 3 |
| Pin 5 | RA4/AN4 — Port A bit 4 / analog input 4 |
| Pin 6 | RA5/AN5 — Port A bit 5 / analog input 5 |
| Pin 7 | RA6/AN6 — Port A bit 6 / analog input 6 |
| Pin 8 | RA7/AN7 — Port A bit 7 / analog input 7 |
| Pin 9 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 10 | OSC2/CLKOUT — Oscillator output |
| Pin 11 | RC0 — Port C bit 0 |
| Pin 12 | RC1 — Port C bit 1 |
| Pin 13 | RC2 — Port C bit 2 |
| Pin 14 | RC3 — Port C bit 3 |
| Pin 15 | RC4 — Port C bit 4 |
| Pin 16 | RC5 — Port C bit 5 |
| Pin 17 | RC6 — Port C bit 6 |
| Pin 18 | RC7 — Port C bit 7 |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply (5V) |
| Pin 21 | RB0/INT0 — Port B bit 0 / external interrupt 0 |
| Pin 22 | RB1/INT1 — Port B bit 1 / external interrupt 1 |
| Pin 23 | RB2/INT2 — Port B bit 2 / external interrupt 2 |
| Pin 24 | RB3 — Port B bit 3 |
| Pin 25 | RB4 — Port B bit 4 |
| Pin 26 | RB5 — Port B bit 5 |
| Pin 27 | RB6 — Port B bit 6 |
| Pin 28 | RB7 — Port B bit 7 |
| Pin 29 | RD0 — Port D bit 0 |
| Pin 30 | RD1 — Port D bit 1 |
| Pin 31 | RD2 — Port D bit 2 |
| Pin 32 | RD3 — Port D bit 3 |
| Pin 33 | RD4 — Port D bit 4 |
| Pin 34 | RD5 — Port D bit 5 |
| Pin 35 | RD6 — Port D bit 6 |
| Pin 36 | RD7 — Port D bit 7 |
| Pin 37 | RE0 — Port E bit 0 |
| Pin 38 | RE1 — Port E bit 1 |
| Pin 39 | RE2 — Port E bit 2 |
| Pin 40 | MCLR/VPP — Master clear reset / programming voltage |
Typical Applications
PIC17LC42A-08/P is suitable for 7 applications: Industrial Control Logic, Motor Drive Sequencing, Instrumentation Front-Ends, Legacy Embedded System Maintenance, Educational Prototyping Platforms, Automotive Aftermarket Controllers, Vending Machine and Kiosk Logic.
Industrial Control Logic
The PIC17LC42A-08/P's 33 I/O pins and deterministic 121 ns instruction cycle at 33 MHz make it well suited to industrial control logic where deterministic loop times are critical. The 4KB OTP program memory holds moderate-complexity PLC-style ladder logic replacements, while the 232 bytes of RAM provide scratchpad storage for sensor state machines. The LC low-power CMOS process reduces quiescent current in always-on machinery controllers. Placed in a 40-pin DIP socket, it is breadboard-friendly for prototyping conveyor sequencing, valve multiplexing, and relay-driving circuits. Compared to a PIC16 mid-range MCU, the PIC17 architecture's 16-bit instruction word reduces instruction count for arithmetic operations by approximately 30 percent, freeing program-memory space for additional fault-handling routines.
Recommended
Motor Drive Sequencing
Stepper motor and brushless DC motor drive sequencing is a strong fit for the PIC17LC42A-08/P because the single-cycle 121 ns instruction execution allows precise commutation timing at high RPM. The 33 I/O pins directly drive phase bridges, encoder feedback inputs, and enable lines without external logic. The 4KB OTP memory accommodates typical trapezoidal and sinusoidal commutation tables for multi-axis drives. The 40-pin PDIP package simplifies prototyping on perfboard and allows socketed firmware upgrades during development. The external oscillator interface permits a high-precision crystal for sub-microsecond timing accuracy in closed-loop velocity regulation.
Recommended
Instrumentation Front-Ends
Legacy laboratory and field instrumentation designs leverage the PIC17LC42A-08/P for front-panel control, keypad scanning, and LCD multiplexing thanks to its 33 I/O pins and deterministic timing. The 8-bit data path handles ADC result buffering in the 232-byte RAM, while the OTP program memory stores calibration tables and user-interface state machines. The 40-pin PDIP footprint remains popular in test equipment because it simplifies in-circuit reprogramming during calibration. The low-power LC process extends battery life in portable instruments, supporting field-deployed data loggers and handheld multimeters where replacement batteries are inconvenient.
Recommended
Legacy Embedded System Maintenance
The PIC17LC42A-08/P serves a critical role in maintaining installed-base legacy embedded systems where firmware compatibility is essential. Medical, aerospace, and industrial-automation equipment designed in the 1990s often uses PIC17C/LC parts whose 16-bit instruction word is not directly portable to PIC16 or PIC18 architectures. Keeping a PIC17LC42A-08/P stock for service replacement avoids costly re-validation cycles. The 40-pin PDIP format matches original PCB footprints exactly, allowing direct socket swaps. Stocking these parts through NRND status is a recognized strategy for sustaining equipment with decade-plus service lifetimes.
Recommended
Educational Prototyping Platforms
The PIC17LC42A-08/P's 40-pin PDIP package and external oscillator interface make it ideal for university and hobbyist prototyping platforms where through-hole soldering is preferred. The 33 I/O pins connect directly to breadboard rails, while the OTP memory allows students to submit programmed parts for graded lab assignments without EEPROM read-back concerns. The 58-instruction orthogonal ISA provides a complete teaching vehicle for assembly language courses within a single lab semester. The 121 ns cycle time at 33 MHz is fast enough for real-time signal processing exercises such as software UARTs, PID controllers, and audio sampling front-ends.
Recommended
Automotive Aftermarket Controllers
The PIC17LC42A-08/P powers aftermarket automotive controllers such as auxiliary lighting drivers, fuel-injection simulators, and gauge-cluster replacements where its 33 I/O pins drive high-current FET bridges and accept multiplexed switch inputs. The 4KB OTP memory holds lookup tables for engine mapping curves, while the 232-byte RAM buffers real-time sensor data. The industrial-temperature PIC17LC42A-08I/P variant is preferred for under-hood installations where ambient temperatures exceed the commercial range. The 40-pin PDIP package simplifies service replacement in field-installed aftermarket units.
Recommended
Vending Machine and Kiosk Logic
Coin acceptor and bill validator interfaces in vending machines rely on the PIC17LC42A-08/P's deterministic interrupt response and 33 I/O count. The 4KB OTP program memory stores pricing tables and inventory state machines, while the 232-byte RAM logs recent transactions. The 40-pin PDIP socket allows quick field replacement by service technicians without specialized rework tools. The low-power LC process reduces standby current draw on mains-powered vending machines, contributing to ENERGY STAR compliance for kiosk-class equipment. The external oscillator supports a precise 32.768 kHz timebase for accurate time-stamping of transactions.
Recommended
Recommended Products Summary
Engineering reference data for PIC17LC42A-08/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17LC42A-08/PQ | PIC17C42A-08/P | PIC17LC44-08/P | PIC17LC42A-08I/P | PIC17C42A-16/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 40-DIP (0.600") | 44-PQFP (PQ) | 40-DIP (same) | 40-DIP (same) | 40-DIP (same) | 40-DIP (same) |
| Program Memory | 4 KB (2K x 16) OTP | 4 KB OTP (same) | 4 KB OTP (same) | 8 KB OTP (+100%) | 4 KB OTP (same) | 4 KB OTP (same) |
| RAM Size | 232 x 8 bytes | 232 x 8 (same) | 232 x 8 (same) | 454 x 8 (+95%) | 232 x 8 (same) | 232 x 8 (same) |
| Max Clock Input | 33 MHz (-08 grade) | 33 MHz (same) | 33 MHz (same) | 33 MHz (same) | 33 MHz (same) | 33 MHz (-16 grade) |
| Number of I/O | 33 | 33 (same) | 33 (same) | 33 (same) | 33 (same) | 33 (same) |
| Process Variant | Low-power CMOS (LC) | Low-power CMOS (same) | Standard CMOS (C) | Low-power CMOS (same) | Low-power CMOS (same) | Standard CMOS (C) |
| Temperature Grade | Commercial | Commercial | Commercial | Commercial | Industrial (-40C to +85C) | Commercial |
Key Differentiators
- Low-power CMOS process variant within the PIC17 family (vs PIC17C42A-08/P)
- Smaller-form-factor drop-in for SMD designs (vs PIC17LC42A-08/PQ)
- Doubled program memory on identical footprint (vs PIC17LC44-08/P)
Design Notes
PIC17C/LC devices use legacy Microchip programming algorithms; verify your device programmer supports the PIC17C4X OTP algorithm before committing to production. Many modern programmers focus on PIC16/18 and dsPIC33 families and lack PIC17 support. The OTP programming window is short (typically 5-10 ms per word) and may require batch programming for high-volume production. For new designs, default to PIC18F or dsPIC33 with Flash memory to avoid OTP programming complications.
The 'LC' low-power CMOS variant of PIC17LC42A-08/P reduces quiescent current versus the standard 'C' variant, but does not implement modern sleep-mode peripherals such as deep-sleep or RTC-only modes found on PIC18F or dsPIC33. Estimated: at 5V and 33 MHz active operation, the PIC17LC42A-08/P draws approximately 25 mA, dropping to about 5 mA in sleep. Add external power switching with a load switch IC if battery life is critical, rather than relying solely on the MCU's sleep modes.
The 40-pin PDIP footprint occupies approximately 0.600 x 2.000 inches of PCB area, which is large by modern embedded standards. For space-constrained designs, consider migrating to the 44-pin PQFP variant (PIC17LC42A-08/PQ) or a modern surface-mount PIC18F in 44-pin TQFP. When using the through-hole DIP, reserve a 40-pin DIP socket to simplify firmware upgrade cycles during development and field service.
Compliance Information
RoHS, REACH, lead-free, and halogen-free status not explicitly stated in the verified web data; recommend confirming with Microchip customer support before specifying in RoHS-compliant designs. The part is not AEC-Q100 qualified; automotive applications should use dsPIC33 AEC-Q100 variants.
