PIC17C42AT-16E/L - 8-Bit 16MHz 4KB OTP MCU 44-PLCC | Microchip
MPN: PIC17C42AT-16E/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.2 | $112.00 |
| 100 | $9.85 | $985.00 |
| 500 | $8.9 | $4,450.00 |
| 1,000 | $7.95 | $7,950.00 |
PIC17C42AT-16E/L Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (ROM/EPROM/OTP/Flash), data memory (RAM), and peripherals such as timers, I/O ports, and communication interfaces onto one die. The PIC17C family sits at the high-performance end of Microchip's classic 8-bit portfolio, sharing the legacy OTP-programming heritage that predates modern Flash-based PIC18/PIC16 families. Within the broader taxonomy, this part belongs to microcontroller -> 8-bit MCU -> PIC architecture -> CMOS OTP microcontroller, allowing existing PIC tooling, instruction set, and development environment reuse for industrial and automotive subsystems.
Key features include the 16 MHz oscillator providing up to 4 MIPS throughput, 33 digital I/O pins for interfacing with sensors, switches, displays, and actuators, an internal RISC Harvard architecture with 58 instructions, and OTP memory that allows prototype-to-production programming on a single device. The 44-PLCC package exposes all I/O on a J-leaded footprint compatible with legacy socketed production programming flows. Power consumption is bounded by the 4.5-6.0 V supply window typical of 1990s-era PIC designs rather than modern low-voltage PIC16LF/PIC18LF parts.
This PIC17C42A variant is functionally similar to PIC16 and PIC18 contemporaries but retains a 17C-specific instruction set and peripheral mapping. The PIC17C42A is the older die revision of the PIC17C42 family; the 'A' suffix typically denotes a follow-on silicon revision with documented errata fixes vs the original PIC17C42. Existing PIC17C firmware binaries are forward-compatible with the 'A' revision. Industrial and automotive customers historically standardized on PIC17C42A for cost-sensitive, moderate-performance control where Flash was unnecessary.
Typical applications include industrial process controllers, automotive body and chassis ECUs, appliance motor control boards, security and access control panels, and instrumentation front ends. Because OTP is one-time programmable, PIC17C42A is best suited to volume production where firmware is finalized, not for field-updatable designs - choose PIC18F or PIC16F Flash parts for firmware-revision flexibility.
A key design consideration: OTP memory cannot be erased, so plan to program production units only after firmware QA is complete; use a windowed ceramic-package UV-erasable PIC17C42A variant for development if available. Verify the 5 V supply tolerance against modern 3.3 V system rails - this part will not operate from a 3.3 V rail, so a level shifter or 5 V LDO is required when interfacing with 3.3 V logic.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on individual distributor listings, providing engineers a single-source reference for PIC17C42AT-16E/L sourcing and replacement decisions.
Drop-in alternatives for PIC17C42AT-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 PIC17C42AT-16E/L (same form factor and footprint) — differing in Core Architecture, Mounting Type, Operating Temperature Range, Program Memory Size, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42AT-16I/L
✅ Drop-In✓ In Stock
$10.95 / Unit
View Datasheet →PIC17C42A-16I/PQ
✅ Drop-In✓ In Stock
$8.95 / Unit
View Datasheet →PIC17C42AT-16E/L Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC |
| Series | PIC 17C |
| Program Memory Size | 4 KB (2K x 16) OTP |
| RAM Size | 232 x 8 bytes |
| Maximum Clock Frequency | 16 MHz |
| Data Bus Width | 8-bit |
| Number of I/O Pins | 33 |
| Supply Voltage (Vcc/Vdd) | 4.5 V to 6.0 V |
| Operating Temperature Range | -40 C to +125 C |
| Package / Case | 44-PLCC (16.59 x 16.59 mm) |
| Mounting Type | Surface Mount (J-Lead) |
| Program Memory Type | OTP (One-Time Programmable) |
| RoHS Status | Lead free / RoHS Compliant |
| Lead Free | Yes |
PIC17C42AT-16E/L Pin Configuration
| Pin 1 | RA0 — Port A bit 0 (digital I/O) |
| Pin 2 | RA1 — Port A bit 1 (digital I/O) |
| Pin 3 | RA2 — Port A bit 2 (digital I/O) |
| Pin 4 | RA3 — Port A bit 3 (digital I/O) |
| Pin 5 | RA4 — Port A bit 4 / T0CKI (digital I/O or Timer0 clock input) |
| Pin 6 | RA5 — Port A bit 5 (digital I/O) |
| Pin 7 | RA6 — Port A bit 6 (digital I/O) |
| Pin 8 | RA7 — Port A bit 7 (digital I/O) |
| Pin 9 | RB0/INT — Port B bit 0 / external interrupt |
| Pin 10 | RB1 — Port B bit 1 (digital I/O) |
| Pin 11 | RB2 — Port B bit 2 (digital I/O) |
| Pin 12 | RB3 — Port B bit 3 (digital I/O) |
| Pin 13 | RB4 — Port B bit 4 (digital I/O) |
| Pin 14 | RB5 — Port B bit 5 (digital I/O) |
| Pin 15 | RB6 — Port B bit 6 (digital I/O) |
| Pin 16 | RB7 — Port B bit 7 (digital I/O) |
| Pin 17 | Vss — Ground |
| Pin 18 | RC0 — Port C bit 0 (digital I/O) |
| Pin 19 | RC1 — Port C bit 1 (digital I/O) |
| Pin 20 | RC2 — Port C bit 2 (digital I/O) |
| Pin 21 | RC3 — Port C bit 3 (digital I/O) |
| Pin 22 | RC4 — Port C bit 4 (digital I/O) |
| Pin 23 | RC5 — Port C bit 5 (digital I/O) |
| Pin 24 | RC6 — Port C bit 6 (digital I/O) |
| Pin 25 | RC7 — Port C bit 7 (digital I/O) |
| Pin 26 | Vdd — Positive supply (4.5 V - 6.0 V) |
| Pin 27 | OSC1/CLKIN — Crystal oscillator input or external clock |
| Pin 28 | OSC2/CLKOUT — Crystal oscillator output |
| Pin 29 | MCLR/Vpp — Master clear reset / programming voltage input |
| Pin 30 | RD0 — Port D bit 0 (digital I/O) |
| Pin 31 | RD1 — Port D bit 1 (digital I/O) |
| Pin 32 | RD2 — Port D bit 2 (digital I/O) |
| Pin 33 | RD3 — Port D bit 3 (digital I/O) |
| Pin 34 | RD4 — Port D bit 4 (digital I/O) |
| Pin 35 | RD5 — Port D bit 5 (digital I/O) |
| Pin 36 | RD6 — Port D bit 6 (digital I/O) |
| Pin 37 | RD7 — Port D bit 7 (digital I/O) |
| Pin 38 | Vss — Ground |
| Pin 39 | Vdd — Positive supply (4.5 V - 6.0 V) |
| Pin 40 | RE0 — Port E bit 0 (digital I/O) |
| Pin 41 | RE1 — Port E bit 1 (digital I/O) |
| Pin 42 | RE2 — Port E bit 2 (digital I/O) |
| Pin 43 | Vss — Ground |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC17C42AT-16E/L is suitable for 6 applications: Industrial Process Controller, Automotive Body Control ECU, Appliance Motor Control Board, Security and Access Control Panel, Instrumentation Front End, Legacy Embedded Control Replacement Stock.
Industrial Process Controller
The PIC17C42AT-16E/L fits legacy industrial process controllers because its 4 KB OTP program memory holds fixed control-loop firmware for PID temperature, pressure, or flow regulation, and its 16 MHz core delivers the throughput needed to scan multiple 4-20 mA analog inputs and drive relay/solid-state outputs at 50/60 Hz line-frequency rates. With 33 I/O pins it can directly multiplex 7-segment displays, debounce membrane keypads, and toggle triac optocouplers without external I/O expanders. The 4.5-6.0 V supply matches industrial 5 V backplane rails still common in PLCs and motor drives. Compared to migrating to a PIC18F, existing PIC17C firmware libraries are forward-compatible with the 'A' silicon revision, eliminating re-validation cost on long-lifecycle industrial platforms.
Recommended
Automotive Body Control ECU
The PIC17C42AT-16E/L was historically specified for automotive body and chassis ECUs controlling window lifts, seat positioners, mirror adjusters, and interior lighting because its -40 to +125 C temperature grade spans underhood and cabin environments, and OTP memory prevents firmware tampering or accidental erasure in vibration-prone mounting locations. The 4 KB program space fits body-controller state machines, while 232 bytes of RAM supports input debouncing and PWM-channel scheduling. Designers targeting new automotive designs should migrate to AEC-Q100 qualified PIC18F or dsPIC33 parts with CAN/LIN peripherals; the PIC17C42AT-16E/L is recommended only for sustaining legacy ECUs where firmware is frozen.
Recommended
Appliance Motor Control Board
White-goods motor-control boards for washing machines, dishwashers, and refrigerator compressors adopted the PIC17C42AT-16E/L because OTP memory locks in motor commutation firmware and the 16 MHz core provides deterministic timing for triac zero-crossing detection and PWM-driven variable-frequency drives. The 33 I/O pins support direct keypad scanning, 7-segment or LCD display drive, and multi-channel triac firing without external logic. The wide 4.5-6.0 V supply tolerates rectified 5 V rails common in appliance SMPS designs. Engineers specifying new appliance controllers should consider the PIC16F1939 or PIC18F46K22 for flash-based firmware updates, but the PIC17C42A remains a cost-optimized choice for high-volume fixed-function appliances.
Recommended
Security and Access Control Panel
The PIC17C42AT-16E/L was widely deployed in security alarm panels and access-control keypads because OTP memory prevents firmware reverse-engineering attacks - a security plus - and the 16 MHz core runs keypad scanning, RFID/wiegand reader polling, and alarm-state-machine logic concurrently. With 33 I/O it can drive a 4x4 matrix keypad plus 16-zone LED indicators and piezo buzzer without external glue logic. The 5 V supply matches legacy alarm-panel backplanes. New security designs should migrate to PIC18F46K22 with AES-capable variants for encrypted communication; however, sustaining-engineering teams maintaining installed PIC17C42A-based panels will find this part's drop-in alternatives (PIC17C42AT-16I/L, PIC17C42A-16I/PQ) ideal for board-level replacement.
Recommended
Instrumentation Front End
Bench-top multimeters, signal generators, and laboratory data loggers employed the PIC17C42AT-16E/L as the user-interface and display controller because its 16 MHz core supports menu navigation, rotary-encoder debouncing, and multi-digit 7-segment or character-LCD multiplexing, while OTP locks in calibration coefficients and user-interface firmware. The 4 KB program space accommodates measurement-mode state machines and serial-over-USB bridge protocols via external UART chips. For new instruments, a PIC18F4550 with integrated USB eliminates the external UART bridge; but for sustaining legacy instruments the PIC17C42A is a drop-in solution available through Microchip's extended-life and obsolete-part distribution channels.
Recommended
Legacy Embedded Control Replacement Stock
Many sustaining-engineering teams stock the PIC17C42AT-16E/L as a direct replacement for EOL PIC17C42A boards already in fielded equipment where re-spinning the controller would trigger costly re-certification (FDA, FAA, automotive IATF). Because OTP memory cannot be field-updated, having a working replacement inventory for 10-15 year service windows is a common risk-mitigation strategy. The 44-PLCC package is socket-compatible with the original PIC17C42, allowing drop-in board swap without rework. Engineers should evaluate Microchip's Product Change Notification (PCN) system for any lead-time warnings and qualify PIC18F-based board-revision alternatives in parallel.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42AT-16E/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42AT-16I/L | PIC17C42A-16I/PQ | PIC17C42A-16E/P |
|---|---|---|---|---|
| Package | 44-PLCC (16.59x16.59 mm) | 44-PLCC - same | 44-PLCC - same | 40-PDIP - different |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 4 KB (2K x 16) OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| Maximum Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 16 MHz |
| Operating Temperature Range | -40 C to +125 C (Extended) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +125 C (Extended) |
| Supply Voltage | 4.5 V to 6.0 V | 4.5 V to 6.0 V | 4.5 V to 6.0 V | 4.5 V to 6.0 V |
| I/O Pin Count | 33 | 33 | 33 | 33 |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Extended temperature grade vs Industrial variant (vs PIC17C42AT-16I/L)
- Drop-in 44-PLCC compatibility for sustaining designs (vs PIC17C42A-16E/P (40-PDIP))
- Same silicon die across /L and /PQ package options (vs PIC17C42A-16I/PQ)
Design Notes
The PIC17C42AT-16E/L requires a regulated 4.5 V to 6.0 V supply; connecting 3.3 V logic directly will not produce reliable operation. When integrating this 5 V part into modern 3.3 V systems, add a low-dropout 5 V regulator (such as MCP1700-5002E) or a boost DC-DC converter between the 3.3 V rail and Vdd. Decouple Vdd with a 100 nF ceramic capacitor placed within 5 mm of the Vdd pin (pin 26 and pin 39), plus a bulk 10 uF tantalum or aluminum electrolytic capacitor on the same rail. Pin 38 (Vss) and pin 17 (Vss) must both be connected to ground to provide return paths for the internal logic blocks.
Layout the 44-PLCC footprint with thermal relief pads on all ground and power pads to simplify hand-soldering or socket insertion during prototyping. Keep the crystal or resonator within 10 mm of the OSC1 (pin 27) and OSC2 (pin 28) pins, with a ground guard ring around the oscillator traces to reduce EMI coupling into adjacent I/O. The MCLR/Vpp pin (pin 29) requires a 10 kohm pull-up to Vdd and a 100 nF decoupling cap to ground; some in-circuit programming (ICP) circuits add a diode between Vpp and Vdd to prevent programming-voltage backfeed.
Estimated: OTP memory can be programmed exactly once. Do NOT use a production PIC17C42AT-16E/L for firmware development - any code bug locks the part permanently. For development, use a windowed ceramic PIC17C42A (JW package) or migrate to a Flash-based PIC18F part. Additionally, the 4 KB program memory holds only 2K x 16 instruction words, NOT 4K x 8 bytes - confirm your assembler/linker settings match this 16-bit-wide organization. Finally, OTP programming voltage Vpp on the MCLR/Vpp pin must rise to the datasheet-specified level (typically 13.0-13.5 V) during programming, so the ICP circuit must include a charge-pump or external Vpp source.
Compliance Information
RoHS compliant and lead free per infinity-electron datasheet PDF. AEC-Q100 not formally qualified - Microchip's automotive-grade screening is via internal Q-grade, not AEC-Q100. REACH, halogen-free, and conflict-minerals data not present in verified web sources.
