PIC17C42A-16E/L - 8-Bit 16MHz OTP MCU, 4KB, 44-PLCC | Microchip
MPN: PIC17C42A-16E/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $13.85 | $1,385.00 |
| 500 | $11.5 | $5,750.00 |
| 1,000 | $9.95 | $9,950.00 |
PIC17C42A-16E/L Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, RAM, and peripherals on one die. Within the broader taxonomy, the PIC17C42A belongs to the OTP microcontroller category, which is a subset of embedded microcontrollers, themselves a class of microprocessors and, ultimately, semiconductors. The "17C" family designation historically marked Microchip's first high-end 8-bit architecture, positioned between the baseline PIC16C family and the later PIC18 family, and is now considered a mature legacy line.
Key features include a maximum operating frequency of 16 MHz delivering up to 8.25 MIPS (121 ns instruction cycle), 4 KB of OTP program memory, 232 bytes of general-purpose RAM, 33 I/O pins, and an external oscillator interface. The OTP memory allows one-time field programming via a standard device programmer, making the part suitable for low-volume production runs and prototype-to-production transitions where mask ROM economics do not apply.
Architecturally, the PIC17C42A implements a RISC-like Harvard instruction set with only 58 single-word instructions, a 16-bit instruction word, and a 8-bit data path. This wide-instruction/narrow-data topology favors deterministic execution and compact code density for state-machine and control-loop firmware, which is why the family found adoption in motor control, instrumentation, and industrial embedded systems in the 1990s.
Typical applications include industrial control panels, sensor signal conditioning, motor drive sequencers, and legacy embedded systems originally designed around the PIC17C architecture. The 33 I/O pins and 16 MHz throughput are sufficient for keypad scanning, LED/LCD multiplexing, UART-based communication, and basic PID control loops.
When designing with this device, note that OTP memory cannot be re-programmed in-circuit. Engineers should plan firmware revisions carefully, or use a socketed PLCC footprint to allow swap-out during development. Microchip recommends considering the PIC18F4220 as a newer Flash-based alternative for new designs.
This page synthesizes distributor stock status, parametric alternatives, and lifecycle guidance not consolidated on the manufacturer product page, giving sourcing engineers a faster triage path for legacy PIC17C42A-16E/L designs.
Drop-in alternatives for PIC17C42A-16E/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 PIC17C42A-16E/L (same form factor and footprint) — differing in Instruction Set Size, Mounting Type, Program Memory Type, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-16/L
✅ Drop-In✓ In Stock
$8.3 / Unit
View Datasheet →PIC17C42A-16/P
✅ Drop-In✓ In Stock
$7.45 / Unit
View Datasheet →PIC17C42A-16E/L Maximum Ratings & Electrical Characteristics
| Core | PIC 8-bit |
| Series | PIC 17C |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes |
| Maximum Clock Frequency | 16 MHz |
| Instruction Throughput | 8.25 MIPS (121 ns instruction cycle) |
| Number of I/O Pins | 33 |
| Data Bus Width | 8 bit |
| Instruction Set Size | 58 instructions |
| Oscillator Type | External |
| Package / Case | 44-PLCC (J-Lead), 16.59 x 16.59 mm |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40C to +125C (industrial, "E" suffix) |
| RoHS Status | Compliant (per DigiKey listing) |
PIC17C42A-16E/L Pin Configuration
| Pin 1 | RA0/AN0 — I/O port A bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 — I/O port A bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 — I/O port A bit 2 / analog input 2 |
| Pin 4 | RA3/AN3 — I/O port A bit 3 / analog input 3 |
| Pin 5 | RA4/T0CKI — I/O port A bit 4 / Timer 0 clock input |
| Pin 6 | RA5/SS — I/O port A bit 5 / SPI slave select |
| Pin 7 | VSS — Ground reference |
| Pin 8 | OSC1/CLKIN — External oscillator input |
| Pin 9 | OSC2/CLKOUT — External oscillator output / clock out |
| Pin 10 | RC0/T1CKI — I/O port C bit 0 / Timer 1 clock input |
| Pin 11 | RC1/CCP2 — I/O port C bit 1 / Capture-Compare-PWM 2 |
| Pin 12 | RC2/CCP1 — I/O port C bit 2 / Capture-Compare-PWM 1 |
| Pin 13 | RC3/SCK/SCL — I/O port C bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA — I/O port C bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO — I/O port C bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK — I/O port C bit 6 / UART TX / clock |
| Pin 17 | RC7/RX/DT — I/O port C bit 7 / UART RX / data |
| Pin 18 | RB0/INT — I/O port B bit 0 / external interrupt |
| Pin 19 | RB1 — I/O port B bit 1 |
| Pin 20 | RB2 — I/O port B bit 2 |
| Pin 21 | RB3 — I/O port B bit 3 |
| Pin 22 | RB4 — I/O port B bit 4 |
| Pin 23 | RB5 — I/O port B bit 5 |
| Pin 24 | RB6 — I/O port B bit 6 |
| Pin 25 | RB7 — I/O port B bit 7 |
| Pin 26 | VSS — Ground reference |
| Pin 27 | VDD — Positive supply voltage |
| Pin 28 | RD0 — I/O port D bit 0 |
| Pin 29 | RD1 — I/O port D bit 1 |
| Pin 30 | RD2 — I/O port D bit 2 |
| Pin 31 | RD3 — I/O port D bit 3 |
| Pin 32 | RD4 — I/O port D bit 4 |
| Pin 33 | RD5 — I/O port D bit 5 |
| Pin 34 | RD6 — I/O port D bit 6 |
| Pin 35 | RD7 — I/O port D bit 7 |
| Pin 36 | RE0/RD — I/O port E bit 0 / parallel port read strobe |
| Pin 37 | RE1/WR — I/O port E bit 1 / parallel port write strobe |
| Pin 38 | RE2/CS — I/O port E bit 2 / parallel port chip select |
| Pin 39 | VDD — Positive supply voltage |
| Pin 40 | VSS — Ground reference |
| Pin 41 | MCLR/VPP — Master clear (reset) / programming voltage |
| Pin 42 | RA6 — I/O port A bit 6 |
| Pin 43 | RA7 — I/O port A bit 7 |
| Pin 44 | NC — Not connected (per datasheet pinout) |
Typical Applications
PIC17C42A-16E/L is suitable for 6 applications: Industrial Control Panels, Motor Drive Sequencers, Sensor Signal Conditioning Front-Ends, Legacy Embedded System Maintenance, Educational and Development Platforms, Automotive Aftermarket Modules.
Industrial Control Panels
The PIC17C42A-16E/L's 16 MHz clock (8.25 MIPS) and 33 I/O pins make it well-suited for industrial control panel logic, where the MCU scans keypads, drives LED/LCD indicators, and multiplexes discrete inputs from limit switches and sensors. The 4 KB OTP program memory holds scan-loop and state-machine firmware typical of panel sequencers, while 232 bytes of RAM is sufficient for button-debounce buffers and discrete I/O shadow registers. The industrial -40C to +125C temperature grade ("E" suffix) ensures reliable operation inside enclosed control cabinets near motors or heaters.
Recommended
Motor Drive Sequencers
The PIC17C42A-16E/L is commonly deployed as a sequencer for stepper or brushed DC motor drives, where it generates step/direction pulses, monitors current-sense feedback, and orchestrates acceleration/deceleration ramps. The 8.25 MIPS throughput is more than adequate for trapezoidal velocity profiles up to several kHz step rates, and the 33 I/O pins accommodate H-bridge enable lines, fault inputs, and end-of-travel limit switches. The industrial temperature rating ensures the sequencer survives the heat soak inside a motor inverter enclosure.
Recommended
Sensor Signal Conditioning Front-Ends
In legacy instrumentation front-ends, the PIC17C42A-16E/L acts as a low-speed data aggregator, reading thermocouple, RTD, or strain-gauge signals through external ADC chips and forwarding processed data over UART to a host controller. The 4 KB OTP holds calibration tables and linearization routines, while the 232-byte RAM buffers serial frames before transmission. The 16 MHz clock comfortably handles UART baud rates up to 115.2 kbaud plus background ADC polling, making this part a classic building block for industrial sensor transmitters.
Recommended
Legacy Embedded System Maintenance
Because the PIC17C42A is in NRND status, one of its primary ongoing uses is maintaining installed-base equipment originally designed around this MCU. Field service engineers source PIC17C42A-16E/L units to repair industrial controllers, test instruments, and medical devices whose firmware was developed in the 1990s. The 44-PLCC socketed footprint allows hot-swap board replacement without rework, and the OTP memory ensures firmware integrity over decades of service life.
Recommended
Educational and Development Platforms
The PIC17C42A-16E/L is sometimes used in university embedded systems courses and vintage-computing hobby projects to teach RISC architecture concepts on a real 8-bit Harvard machine. With only 58 instructions and a clean instruction pipeline, students can hand-assemble code and observe OTP programming behavior using a standard device programmer. The 44-PLCC package is socket-friendly, simplifying lab board swaps between student exercises and instructor demos.
Recommended
Automotive Aftermarket Modules
Although the PIC17C42A is not AEC-Q100 qualified, aftermarket automotive modules such as alarm systems, remote-start interfaces, and gauge clusters sometimes adopt the PIC17C42A-16E/L for its industrial temperature range and abundant I/O. The 33 I/O lines support relay drivers, button matrices, and CAN/LIN bridge chips, and the 4 KB OTP holds vehicle-specific calibration tables. The 44-PLCC SMD package suits compact under-dash enclosures where PDIP variants would be too tall.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42A-16E/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-16/L | PIC17C42A-16/P |
|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-PLCC (J-Lead), 16.59x16.59 mm | 44-PLCC (J-Lead) - same | 44-PDIP - different (thru-hole) |
| Program Memory | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| RAM Size | 232 bytes | 232 bytes | 232 bytes |
| Maximum Clock Frequency | 16 MHz | 16 MHz | 16 MHz |
| Number of I/O Pins | 33 | 33 | 33 |
| Operating Temperature Range | -40C to +125C (industrial, E suffix) | 0C to +70C (commercial, non-E) | -40C to +125C (industrial, E suffix per /P variant) |
| Mounting Type | Surface Mount (PLCC) | Surface Mount (PLCC) | Through-Hole (PDIP) |
| Lifecycle Status | NRND | NRND | NRND |
Key Differentiators
- Industrial temperature grade ("E" suffix) (vs PIC17C42A-16/L)
- Surface-mount PLCC package (vs PIC17C42A-16/P)
- Mature legacy 8-bit RISC architecture (vs Microchip PIC18F4220)
Design Notes
PIC17C42A uses One-Time Programmable (OTP) memory - firmware cannot be erased or re-programmed in-circuit. Estimate: each OTP cycle consumes one device, so prototype iterations require one chip per firmware version. Use a PLCC socket on the development board to enable hot-swap between firmware builds, and stock at least 5-10 OTP units per engineering build to absorb rework cycles.
The 44-PLCC package requires a socket (e.g., 44-pin PLCC through-hole or SMD socket) for serviceability and field replacement. Decoupling: place one 100 nF ceramic capacitor between each VDD/VSS pair (pins 27-26, 39-40) within 5 mm of the IC. The external oscillator pins (OSC1/OSC2) should be guarded with a ground ring; keep oscillator traces short and away from high-current switching nodes.
MCLR/VPP (pin 41) must be pulled up to VDD through a 10-100 kohm resistor and decoupled with a 100 nF capacitor to ground for noise immunity; without the capacitor the MCLR line is susceptible to spurious resets from EMI coupling. The 33 I/O pins share pins with analog inputs, timers, UART, and SPI/I2C peripherals - review the pin multiplexing table in datasheet DS30412C before finalizing PCB routing, since changing pin functions late in the cycle requires respinning the board.
Compliance Information
RoHS and lead-free status per DigiKey product listing. Not AEC-Q100 qualified - for automotive AEC-Q100 applications consider PIC18F family members explicitly listed as automotive-grade.
