PIC17C42A-33E/L - 8-Bit 33MHz OTP MCU 4KB 44-PLCC | Microchip
MPN: PIC17C42A-33E/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.4 | $164.00 |
| 100 | $13.95 | $1,395.00 |
| 500 | $11.8 | $5,900.00 |
| 1,000 | $10.2 | $10,200.00 |
PIC17C42A-33E/L Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and peripheral interfaces into one IC. The PIC17C42A family sits in the mid-range tier of Microchip's 8-bit PIC architecture hierarchy - above PIC16C5X baseline parts and below PIC18C enhanced devices. PIC17C MCUs are built around a 16-bit-wide instruction word (2K x 16 = 4 KB OTP program memory) with an 8-bit data path, providing roughly double the code density and arithmetic throughput of the PIC16C baseline family while remaining assembly-source compatible upwards into PIC18C and later PIC18F flash parts.
Key features include 4 KB (2K x 16) OTP program memory, 232 x 8 bytes of general-purpose RAM, 33 digital I/O lines, and on-chip peripherals such as a Universal Synchronous/Asynchronous Receiver-Transmitter (USART), Pulse Width Modulation (PWM) module, Watchdog Timer (WDT), and Power-On Reset (POR). An external oscillator input supports crystals, resonators, or external clock sources up to 33 MHz, and the device operates across a 4.5 V to 6.0 V supply range typical for early-1990s CMOS MCUs.
Architecture-wise, the PIC17C42A uses a RISC-style Harvard design with 58 single-word instructions, single-cycle instruction decode, and a 121 ns minimum instruction execution time at 33 MHz. The Harvard split between 16-bit program memory and 8-bit data RAM eliminates the von Neumann fetch bottleneck, and a hardware multiply option accelerates integer math. Compared with PIC16C5X parts at the same clock, the PIC17C42A typically delivers 2x-4x higher sustained throughput, which is why it was positioned for more demanding embedded applications in the mid-1990s.
Typical applications include industrial control systems, motor and stepper control, smart sensor interfaces, instrumentation, and embedded communication controllers. The wide industrial temperature range makes the 'E' grade suitable for factory-floor equipment and outdoor enclosures, while the PIC18F4220 is recommended as the modern flash-reprogrammable migration target for new designs. Because PIC17C42A is OTP, firmware is locked at wafer programming, so this part is best suited for high-volume production runs where code does not change in the field.
When designing with the PIC17C42A-33E/L, budget PCB area for the 44-PLCC socket or reflow footprint, decouple VDD with a 0.1 uF ceramic plus 10 uF tantalum, and ensure the oscillator trace is short and guarded to avoid noise pickup at 33 MHz. For new designs Microchip explicitly recommends migrating to PIC18F4220, which is flash-based, pin-compatible in many board layouts, and supported by current MPLAB X toolchains.
This page synthesizes distributor pricing, drop-in alternatives within the PIC17C family, and practical design notes not found on the manufacturer datasheet front page.
Drop-in alternatives for PIC17C42A-33E/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-33E/L (same form factor and footprint) — differing in Package, Mounting Type, Program Memory Type, RAM Size, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-33E/PT
✅ Drop-In✓ In Stock
$8.5 / Unit
View Datasheet →PIC17C42AT-33I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C42A-33/PT
✅ Drop-In✓ In Stock
$9.65 / Unit
View Datasheet →PIC17C42A-25E/P
✅ Drop-In✓ In Stock
$5.6 / Unit
View Datasheet →PIC17C42A-16E/P
✅ Drop-In✓ In Stock
$5.85 / Unit
View Datasheet →PIC17C42A-33E/L Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit (Harvard, RISC) |
| Family | PIC17C series |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes |
| Maximum Clock Speed | 33 MHz |
| Instruction Execution Time | 121 ns (8.25 MIPS) |
| Instruction Set Size | 58 single-word instructions |
| Number of I/O Pins | 33 |
| Supply Voltage (Vdd) | 4.5 V to 6.0 V |
| Oscillator Type | External (crystal/resonator/clock) |
| Package | 44-PLCC (J-Lead), 16.59 x 16.59 mm |
| Operating Temperature (E grade) | -40 C to +125 C |
| On-chip Peripherals | USART, PWM, WDT, POR |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (lead-free 'L' suffix) |
| Lead Finish | Matte Tin (Pb-free) |
PIC17C42A-33E/L Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 4 | RA3/AN3 — PORTA bit 3 / analog input 3 |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer 0 clock input |
| Pin 6 | RA5/SS — PORTA bit 5 / SPI slave select |
| Pin 7 | RA6/RCV — PORTA bit 6 / USART receive |
| Pin 8 | RA7/TX — PORTA bit 7 / USART transmit |
| Pin 9 | OSC1/CLKIN — External oscillator input |
| Pin 10 | OSC2/CLKOUT — External oscillator output / clock out |
| Pin 11 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 12 | RB1 — PORTB bit 1 |
| Pin 13 | RB2 — PORTB bit 2 |
| Pin 14 | RB3 — PORTB bit 3 |
| Pin 15 | RB4 — PORTB bit 4 |
| Pin 16 | RB5 — PORTB bit 5 |
| Pin 17 | RB6 — PORTB bit 6 |
| Pin 18 | RB7 — PORTB bit 7 |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply (4.5 V to 6.0 V) |
| Pin 21 | RC0 — PORTC bit 0 |
| Pin 22 | RC1 — PORTC bit 1 |
| Pin 23 | RC2 — PORTC bit 2 |
| Pin 24 | RC3 — PORTC bit 3 |
| Pin 25 | RC4 — PORTC bit 4 |
| Pin 26 | RC5 — PORTC bit 5 |
| Pin 27 | RC6 — PORTC bit 6 |
| Pin 28 | RC7 — PORTC bit 7 |
| Pin 29 | RD0 — PORTD bit 0 |
| Pin 30 | RD1 — PORTD bit 1 |
| Pin 31 | RD2 — PORTD bit 2 |
| Pin 32 | RD3 — PORTD bit 3 |
| Pin 33 | RD4 — PORTD bit 4 |
| Pin 34 | RD5 — PORTD bit 5 |
| Pin 35 | RD6 — PORTD bit 6 |
| Pin 36 | RD7 — PORTD bit 7 |
| Pin 37 | RE0/AN5 — PORTE bit 0 / analog input 5 |
| Pin 38 | RE1/AN6 — PORTE bit 1 / analog input 6 |
| Pin 39 | RE2/AN7 — PORTE bit 2 / analog input 7 |
| Pin 40 | MCLR/VPP — Master clear reset / programming voltage |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC17C42A-33E/L is suitable for 7 applications: Industrial Process Control, Motor and Stepper Control, Smart Sensor Interfaces, Embedded Communication Controllers, Test and Measurement Instrumentation, Automotive Body Electronics (Legacy), Legacy Embedded Product Sustainment.
Industrial Process Control
The PIC17C42A-33E/L is well matched to industrial process controllers that demand deterministic 8-bit performance across the -40 C to +125 C extended industrial range. At 33 MHz it executes instructions in 121 ns, fast enough to scan 33 I/O lines and execute PID calculations within typical 1 ms control loops. The on-chip USART links to operator panels or PLC backplanes, while the PWM module drives valve actuators or heater elements. Its 4 KB OTP holds fixed control firmware in high-volume OEM builds, and the 44-PLCC package accepts standard production sockets for field service.
Recommended
Motor and Stepper Control
Stepper motor controllers and small BLDC drivers benefit from the PIC17C42A-33E/L's PWM module and 33 MHz throughput. The PWM peripheral can drive MOSFET H-bridges directly for low-power stepper motors, while the 121 ns instruction time supports commutation tables for sensorless or Hall-sensed BLDC motors running at tens of thousands of RPM. The extended temperature grade allows placement in motor housings where ambient can exceed 85 C, and the 33 I/O pins accommodate Hall sensors, end-stop switches, and enable lines without external I/O expanders.
Recommended
Smart Sensor Interfaces
Sensor hubs that aggregate analog inputs and present them over a serial link are a natural fit for the PIC17C42A-33E/L. The USART provides RS-232/RS-485 connectivity to host controllers, and the 33 I/O lines multiplex multiple SPI or I2C sensor chains. While the PIC17C42A itself has no on-chip ADC, designers pair it with external ADCs such as the MCP3208 over SPI. The 4 KB OTP suits fixed sensor-calibration firmware in volume OEM products like HVAC transmitters or weigh-scale indicators.
Recommended
Embedded Communication Controllers
Protocol-bridging and serial-multiplexing applications leverage the PIC17C42A-33E/L's USART plus GPIO-driven bit-banging capability. At 33 MHz the part can implement half-duplex protocols such as Modbus RTU, DMX-512, or vendor-specific RS-485 frames while simultaneously polling status LEDs and discrete inputs. The extended temperature grade supports deployment in outdoor or cabinet-mounted equipment, and the 4 KB OTP suffices for fixed protocol stacks that do not require firmware updates after deployment.
Recommended
Test and Measurement Instrumentation
Bench-top instruments and panel meters that require deterministic timing benefit from the PIC17C42A-33E/L's predictable 121 ns instruction cycle. The PWM peripheral drives analog meters or LED bar-graph displays, the USART outputs data to a host PC, and the Watchdog Timer protects unattended test fixtures from firmware lockups. The extended industrial temperature range ensures stability in laboratory environments with poor HVAC, while the 44-PLCC package is easy to socket for factory calibration and field repair.
Recommended
Automotive Body Electronics (Legacy)
Pre-CAN body-control modules built in the late 1990s and early 2000s often specified the PIC17C42A-33E/L because of its extended temperature grade and stable 33 MHz throughput. The PWM module drives bulb dimmers and small DC loads, while the USART links to dash-cluster displays. Although Microchip now recommends the PIC18F family for new automotive designs, the PIC17C42A-33E/L continues to appear in service replacement BOMs for legacy body controllers where the firmware has been locked in OTP silicon.
Recommended
Legacy Embedded Product Sustainment
Many OEM products that shipped in the 1990s and early 2000s designed around the PIC17C42A-33E/L are still in field service, and this part supports those long-life sustainment programs. The 4 KB OTP holds locked firmware, the 232-byte RAM sustains minimal stack and buffer use, and the 44-PLCC socket allows board-level swap repairs without re-flow. Engineers maintaining these products should plan a migration to PIC18F4220 once OTP stocks deplete, using an adapter PCB to bridge 44-PLCC to 44-TQFP footprints during the transition.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42A-33E/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-33E/PT | PIC17C42AT-33I/PT | PIC17C42A-33/PT | PIC17C42A-25E/P | PIC17C42A-16E/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-PLCC (J-Lead) | 44-TQFP - different footprint | 44-TQFP - different footprint | 44-TQFP - different footprint | 40-PDIP - different footprint | 40-PDIP - different footprint |
| Maximum Clock Speed | 33 MHz | 33 MHz | 33 MHz | 33 MHz | 25 MHz | 16 MHz |
| Program Memory | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| RAM Size | 232 x 8 bytes | 232 x 8 bytes | 232 x 8 bytes | 232 x 8 bytes | 232 x 8 bytes | 232 x 8 bytes |
| Operating Temperature | -40 C to +125 C (E grade) | -40 C to +125 C (E grade) | -40 C to +85 C (I grade) | 0 C to +70 C (commercial) | -40 C to +125 C (E grade) | -40 C to +125 C (E grade) |
| Number of I/O Pins | 33 | 33 | 33 | 33 | 33 (40-pin PDIP) | 33 (40-pin PDIP) |
| On-chip Peripherals | USART, PWM, WDT, POR | USART, PWM, WDT, POR | USART, PWM, WDT, POR | USART, PWM, WDT, POR | USART, PWM, WDT, POR | USART, PWM, WDT, POR |
| 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 | 4.5 V to 6.0 V | 4.5 V to 6.0 V |
Key Differentiators
- Extended industrial temperature grade in PLCC (vs PIC17C42AT-33I/PT)
- Socketable 44-PLCC package for serviceability (vs PIC17C42A-33E/PT (TQFP))
- 33 MHz speed grade in extended temperature (vs PIC17C42A-25E/P (25 MHz))
Design Notes
Decouple VDD (pin 20) with a 0.1 uF ceramic in parallel with a 10 uF tantalum placed within 5 mm of the package. The PIC17C42A-33E/L draws transient currents during oscillator startup and peripheral switching; bulk capacitance prevents VDD droops that can trigger the on-chip Power-On Reset. Place a ferrite bead in series with VDD if the supply rail shares switching converter noise. Estimated: at 33 MHz and full I/O toggle, peak supply current can briefly exceed 30 mA.
Keep the OSC1/OSC2 traces (pins 9 and 10) short - under 10 mm total length - and guard them with a ground pour on both sides. At 33 MHz the oscillator edge rates are sharp; long traces pick up EMI and can shift the effective frequency or cause oscillator start-up failures at temperature extremes. For high-noise environments add a 10-100 ohm resistor in series with OSC2 to dampen reflections.
The PIC17C42A-33E/L is OTP, so firmware cannot be field-updated - verify code in a windowed PIC17C42AT sample or a PIC18F4220 prototype before committing to OTP programming. Plan a migration to PIC18F4220 since Microchip has marked the PIC17C family obsolete. Also confirm the MCLR pin (pin 40) has a 10 kohm pull-up to VDD; floating MCLR causes intermittent resets that are hard to debug.
At -40 C to +125 C the PIC17C42A-33E/L is specified for full-speed operation, but oscillator behaviour shifts with temperature. For designs operating above 100 C ambient, characterise the chosen crystal or resonator across the full temperature range - many AT-cut crystals pull more than 50 ppm at 125 C, which may push the 33 MHz clock out of spec. A TCXO or external clock source is recommended for high-temperature deployments. Estimated: a 30 ppm crystal at 125 C may shift to 50 ppm, yielding a clock error of approximately 1.6 kHz at 33 MHz.
Compliance Information
RoHS compliant per the 'L' suffix (lead-free 44-PLCC). Not AEC-Q100 qualified - for automotive deployments confirm with Microchip. Halogen-free status not explicitly stated in verified data; treat as unknown.
