PIC17C42A-33/L - 8-bit 33MHz 4KB OTP MCU 33 I/O | Microchip
MPN: PIC17C42A-33/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.45 | $12.45 |
| 10 | $11.2 | $112.00 |
| 100 | $9.85 | $985.00 |
| 500 | $8.5 | $4,250.00 |
| 1,000 | $7.25 | $7,250.00 |
PIC17C42A-33/L Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (ROM/OTP/Flash), data RAM, and peripheral interfaces onto one die. PIC microcontrollers use a Harvard RISC architecture with a small, fixed instruction set optimized for deterministic embedded control. MCUs sit at the lowest tier of the embedded-compute hierarchy: MCU -> microcontroller -> embedded processor -> semiconductor IC. They differ from microprocessors (MPUs) by integrating non-volatile memory and peripherals on-chip, eliminating external bus complexity for compact, low-power designs.
Key features of the PIC17C42A-33/L include the PIC17C's enhanced 8-bit core, hardware multiplier, expanded peripheral set (including a USART, capture/compare/PWM, and multiple timers), and 33 bidirectional I/O lines capable of sourcing/sinking 25 mA per pin. The 33 MHz clock rate and 16-bit wide program bus yield 8.25 MIPS, more than doubling PIC16 throughput. Wide operating voltage (4.5 V to 6.0 V typical for the OTP variant) and low power consumption suit battery and line-powered products alike.
The architecture combines a 16-bit program bus with an 8-bit data bus, allowing single-cycle 16-bit instruction fetches while preserving 8-bit ALU throughput. The high-current I/O pins can directly drive LEDs, relays, and triac interfaces, reducing external driver circuitry. The PIC17C4X instruction set adds hardware multiply and a 16-bit program counter for C-language efficiency.
Typical applications include industrial control systems, motor control, LED display drivers, appliance controllers, smart sensors, and embedded instrumentation. The PIC17C42A-33/L is also well suited to prototyping designs that later migrate to flash-based PIC18F successors (Microchip recommends the PIC18F4220 as the modern functional replacement).
When designing with this OTP part, plan code development with a windowed UV-erasable PIC17C42A-16/P before committing to one-time-programmed production units. Decoupling the VDD/VSS pair with 0.1 uF ceramics and reserving RA4 as an open-drain output are common pitfalls to avoid. Page referenced: PIC17C4X preliminary data sheet (DS30412C).
This page synthesizes distributor stock and pricing from DigiKey, Mouser, Bonchip, Kynix, and Hotenda, plus pin-compatible PIC17C family alternatives and practical design notes not found in the original manufacturer datasheet.
Drop-in alternatives for PIC17C42A-33/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-33/L (same form factor and footprint) — differing in Mounting Type, Operating Temperature Range, Package, Program Memory Type, Oscillator Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42AT-33/L
✅ Drop-In✓ In Stock
$5.85 / Unit
View Datasheet →PIC17C42A-25/L
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC17C42A-16/L
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$8.3 / 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-33/L Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Family | PIC17C |
| Core Architecture | PIC Harvard RISC |
| Program Memory Type | OTP (One-Time-Programmable) EPROM |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes |
| Maximum CPU Frequency | 33 MHz |
| Instruction Execution Time | 121 ns (8.25 MIPS) |
| Number of I/O Pins | 33 |
| Oscillator Type | External |
| Package / Case | 44-LCC (J-Lead), PLCC-44 |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40C to +85C (industrial, /L suffix) |
| Supply Voltage Range | 4.5 V to 6.0 V (typical OTP spec) |
| I/O Pin Drive | 25 mA source/sink per pin |
| Peripherals | USART, Capture/Compare/PWM, Timers |
| RoHS Status | Non-compliant (legacy OTP, lead-bearing PLCC) |
PIC17C42A-33/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/TOCKI — PORTA bit 4 / Timer0 clock input (open-drain) |
| Pin 6 | RA5/AN4 — PORTA bit 5 / Analog input 4 |
| Pin 7 | RA6/OSC2 — PORTA bit 6 / Oscillator output |
| Pin 8 | RA7/OSC1 — PORTA bit 7 / Oscillator input |
| Pin 9 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 10 | RB1 — PORTB bit 1 |
| Pin 11 | RB2 — PORTB bit 2 |
| Pin 12 | RB3 — PORTB bit 3 |
| Pin 13 | RB4 — PORTB bit 4 |
| Pin 14 | RB5 — PORTB bit 5 |
| Pin 15 | RB6 — PORTB bit 6 |
| Pin 16 | RB7 — PORTB bit 7 |
| Pin 17 | VDD — Positive supply voltage |
| Pin 18 | VSS — Ground reference |
| Pin 19 | RC0 — PORTC bit 0 |
| Pin 20 | RC1 — PORTC bit 1 |
| Pin 21 | RC2 — PORTC bit 2 |
| Pin 22 | RC3 — PORTC bit 3 |
| Pin 23 | RC4 — PORTC bit 4 |
| Pin 24 | RC5 — PORTC bit 5 |
| Pin 25 | RC6 — PORTC bit 6 |
| Pin 26 | RC7 — PORTC bit 7 |
| Pin 27 | RD0 — PORTD bit 0 |
| Pin 28 | RD1 — PORTD bit 1 |
| Pin 29 | RD2 — PORTD bit 2 |
| Pin 30 | RD3 — PORTD bit 3 |
| Pin 31 | RD4 — PORTD bit 4 |
| Pin 32 | RD5 — PORTD bit 5 |
| Pin 33 | RD6 — PORTD bit 6 |
| Pin 34 | RD7 — PORTD bit 7 |
| Pin 35 | RE0/RD — PORTE bit 0 / Read control |
| Pin 36 | RE1/WR — PORTE bit 1 / Write control |
| Pin 37 | RE2/CS — PORTE bit 2 / Chip select |
| Pin 38 | VDD — Positive supply voltage (second VDD pin) |
| Pin 39 | OSC1/CLKIN — Oscillator crystal input / external clock |
| Pin 40 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| Pin 41 | MCLR/VPP — Master clear reset / Programming voltage |
| Pin 42 | VSS — Ground reference (second VSS pin) |
| Pin 43 | NC — Not connected (per datasheet PLCC-44 layout) |
| Pin 44 | NC — Not connected (per datasheet PLCC-44 layout) |
Typical Applications
PIC17C42A-33/L is suitable for 6 applications: Industrial Process Control, Motor Control and PWM Drives, LED Display and Signage Controllers, Appliance Control Systems, Smart Sensor Hubs, Embedded Instrumentation.
Industrial Process Control
The PIC17C42A-33/L's 33 I/O pins and 25 mA source/sink capability make it well suited to industrial process controllers driving relays, solenoids, and indicator lamps directly. The 33 MHz core delivers 8.25 MIPS throughput, sufficient for PID loop computation, sensor multiplexing, and HMI keypad scanning in a single chip. Hardware USART enables direct RS-232/RS-485 communication with PLC backplanes, and the Capture/Compare/PWM peripheral generates timing pulses for proportional valve control. The -40C to +85C industrial temperature range tolerates factory floor environments without derating. Compared with discrete logic controllers, the integrated OTP memory reduces PCB area while the Harvard architecture ensures deterministic interrupt response for safety-critical interlocks.
Recommended
Motor Control and PWM Drives
The PIC17C42A-33/L's Capture/Compare/PWM module generates the PWM waveforms required for DC motor speed control, while the 33 MHz instruction rate (121 ns cycle) sustains real-time current-loop closure at 20 kHz PWM frequencies. The 25 mA I/O drive directly interfaces to logic-level MOSFET gate drivers without external buffers, and the 33 I/O pins accept quadrature encoder feedback, limit-switch inputs, and fault signals simultaneously. The Harvard RISC pipeline keeps interrupt latency bounded for over-current protection. Industrial temperature grade permits deployment in traction, pump, and HVAC blower systems where -40C cold-crank is required. Engineers transitioning new designs should target the PIC18F4331 which adds dedicated motor-control PWM hardware.
Recommended
LED Display and Signage Controllers
LED matrix displays and scrolling signs benefit from the PIC17C42A-33/L's 33 high-current I/O pins, each capable of sinking 25 mA to drive LED segments or row/column multiplex lines directly. At 8.25 MIPS, the core sustains 8x8 to 16x16 matrix refresh at flicker-free rates (>100 Hz) while executing text-scrolling algorithms. The external oscillator input accommodates crystals from DC to 33 MHz, allowing precise multiplex timing without external PLLs. The OTP program memory holds fixed character fonts and animation tables at production cost below Flash equivalents. The PLCC-44 footprint simplifies chassis-mount assembly for commercial signage and traffic information boards where long-term availability of legacy designs is acceptable.
Recommended
Appliance Control Systems
White-goods appliances such as washing machines, dishwashers, and microwave ovens deploy the PIC17C42A-33/L to manage user interfaces, sensor inputs, and actuator outputs in a single integrated controller. The 33 I/O lines connect directly to membrane keypads, seven-segment displays, and triac-driven AC loads, eliminating external glue logic. The 8.25 MIPS throughput runs multi-tasking control loops for water-level sensing, temperature regulation, and timing sequences. The wide 4.5-6.0 V supply tolerates rectified mains rails common in cost-sensitive appliance designs. Production engineers favor OTP for its low unit cost and one-time code security preventing unauthorized firmware cloning.
Smart Sensor Hubs
Multi-sensor data acquisition nodes use the PIC17C42A-33/L to aggregate analog and digital signals from temperature, pressure, and flow sensors into a single processing unit. The 33 MHz throughput supports 10-bit ADC sampling at rates sufficient for vibration monitoring and acoustic analysis. The USART peripheral streams processed telemetry to a host gateway over RS-232 or RS-485, while the 33 I/O lines accept multiplexed analog inputs through external analog switches. Industrial temperature range and robust 25 mA I/O make it viable for outdoor sensor pods, building automation, and HVAC monitoring. Compact PLCC-44 packaging fits in standard sensor enclosures.
Recommended
Embedded Instrumentation
Test and measurement instruments including bench multimeters, panel meters, and data loggers leverage the PIC17C42A-33/L's deterministic interrupt response and 33 MHz processing headroom. The Harvard RISC core executes floating-point math libraries in acceptable cycle counts for RMS and statistical computations on 8-bit ADC data. The Capture/Compare/PWM peripheral generates timing signals for frequency counters, while the USART interfaces to PC-based logging software. With 4 KB OTP and 232 B RAM, the device stores calibration constants and small look-up tables for linearization. The PLCC-44 mechanical package withstands bench-top instrumentation thermal cycling.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42A-33/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42AT-33/L | PIC17C42A-25/L | PIC17C42A-16/L | PIC17C42A-25E/P | PIC17C42A-16E/P |
|---|---|---|---|---|---|---|
| Package | 44-PLCC (J-Lead) | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum CPU Frequency | 33 MHz | 33 MHz | 25 MHz (-24%) | 16 MHz (-52%) | 25 MHz (-24%) | 16 MHz (-52%) |
| Program Memory | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| RAM Size | 232 bytes | 232 bytes | 232 bytes | 232 bytes | 232 bytes | 232 bytes |
| Number of I/O Pins | 33 | 33 | 33 | 33 | 33 | 33 |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +125C (extended) | -40C to +125C (extended) |
| Lifecycle | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Only 33 MHz speed grade in the PIC17C42A family (vs PIC17C42A-25/L)
- Tape-and-reel variant simplifies SMD assembly (vs PIC17C42A-33/L (tube))
- Industrial temperature range only (vs PIC17C42A-25E/P)
Design Notes
The PIC17C42A-33/L operates from 4.5 V to 6.0 V; decouple VDD/VSS with a 0.1 uF ceramic placed within 5 mm of the supply pins (pin 17 VDD, pin 18 VSS, plus the redundant pin 38 VDD, pin 42 VSS pair on PLCC-44). Estimated: at 33 MHz and full I/O toggling, core current draw is approximately 25-35 mA depending on output loading - budget 50 mA for the regulator headroom. Power-on reset requires VDD rise time below 50 ms; if a slow RC ramp is used, hold MCLR low until VDD stabilizes.
Route the external clock traces (OSC1/CLKIN pin 39, OSC2/CLKOUT pin 40) symmetrically and shield them from high-current switching outputs to avoid jitter at 33 MHz. Keep crystal traces short (<10 mm) and guard the oscillator ground return with a dedicated via to the ground plane. PLCC-44 socket designs should use a low-profile machined-pin socket to maintain signal integrity at the 33 MHz edge rate. Place the MCLR/VPP pull-up resistor within 5 mm of pin 41 and route it away from analog inputs to prevent programming-voltage noise coupling.
Three pitfalls to avoid: (1) RA4 is an open-drain output and requires a pull-up resistor when driving LED or logic-high loads - it cannot source current. (2) Since OTP cannot be reprogrammed, always prototype with the UV-erasable PIC17C42A-16/P windowed package or the flash-based PIC18F4220 before committing to PIC17C42A-33/L production units. (3) The PIC17C instruction set differs from PIC16C and PIC18F; existing PIC16 code requires recompilation against the PIC17C compiler and verification of interrupt vector layouts and banking. Estimated: rewriting 1 KLOC of PIC16C code typically reveals 5-15% timing-dependent modifications needed for PIC17C.
Compliance Information
Legacy OTP PIC17C42A-33/L is non-RoHS compliant due to lead-bearing PLCC-44 packaging and OTP EPROM cell construction. Not AEC-Q100 qualified; PIC17C42A-25E/P and PIC17C42A-16E/P with extended temperature grade are not automotive-qualified either. Microchip's part marking 'L' suffix indicates industrial temperature range, not lead-free status.
