PIC17C42A-33I/P - 33MHz 8-bit OTP MCU 4KB | Microchip
MPN: PIC17C42A-33I/P ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.62 | $9.62 |
| 10 | $8.85 | $88.50 |
| 100 | $7.62 | $762.00 |
| 500 | $6.85 | $3,425.00 |
| 1,000 | $6.2 | $6,200.00 |
PIC17C42A-33I/P Overview
The PIC family (Peripheral Interface Controller) is a category of 8-bit RISC microcontrollers originally developed by General Instrument and now owned and evolved by Microchip Technology. PIC microcontrollers use a Harvard architecture with separate program and data buses, enabling single-cycle instruction fetch plus operand read for predictable execution timing. The PIC17C subgroup within PIC was the first PIC family to deliver MIPS-class (millions of instructions per second) throughput to 8-bit applications, enabling complex control loops, encoder interfaces, and multi-axis motor control.
Key features of the PIC17C42A include an 8.25 MIPS instruction throughput at 33 MHz, a 16-bit instruction word, 8-level hardware stack, a 16-bit timer/counter with 8-bit prescaler, two 8-bit timer/counters, hardware USART with 9-bit address support, two analog comparators, capture/compare/PWM (CCP) modules, and a watchdog timer with on-chip oscillator. The instruction set contains only 58 single-word instructions, and the device is fully upwards compatible with the PIC16C5X, PIC12CXXX, and PIC16CXX families.
Typical applications include industrial automation controllers, motor control front-ends, automotive body electronics, office equipment, sensor signal conditioning, and instrumentation. The high-throughput 8-bit core makes it well-suited to PID loops, encoder pulse counting, and protocol bridging tasks where deterministic timing matters more than raw word width.
When designing with this device, note that OTP memory is programmed once and cannot be erased; for field-upgradable firmware consider the PIC18F or PIC16F flash-based equivalents. Provide adequate decoupling on VDD and AVSS pins and respect the 5V supply tolerance; this is not a 3.3V-tolerant part. The OEM programmer support (MPLAB-ICD, PRO MATE) is mature but the silicon is mature lifecycle and not recommended for new designs - Microchip recommends PIC18F4220 as the modern successor.
Drop-in alternatives for PIC17C42A-33I/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 PIC17C42A-33I/P (same form factor and footprint) — differing in Package, Program Memory Type, Operating Temperature Range, Oscillator Type, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-33/PT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$9.65 / Unit
View Datasheet →PIC17C42A-25E/P
✅ Drop-In✓ In Stock
$5.6 / Unit
View Datasheet →PIC17C42A-25/PT
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$5.55 / Unit
View Datasheet →PIC17C42A-16E/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$5.85 / Unit
View Datasheet →PIC17C42A-16/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$7.45 / Unit
View Datasheet →PIC17C42A-33I/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC17 8-bit RISC (Harvard) |
| Instruction Set | 58 single-word instructions |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 4 KB (2K x 16) |
| Data RAM Size | 232 bytes |
| Number of I/O Pins | 33 |
| Maximum Clock Frequency | 33 MHz |
| Instruction Execution Time | 121 ns (8.25 MIPS) |
| Supply Voltage (VDD) | 5 V |
| Operating Temperature Range | -40C to +85C (Industrial) |
| Package Type | 40-pin PDIP (Plastic DIP, 0.600 inch / 15.24 mm) |
| Mounting Type | Through-hole |
| On-chip Peripherals | USART, 2x Comparators, 1x 16-bit Timer, 2x 8-bit Timers, WDT, CCP |
| Hardware Stack | 8 levels x 16-bit |
| Temperature Grade | Industrial (I) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC17C42A-33I/P Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset, active low) / Programming voltage input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 4 | RA2 — PORTA bit 2, open-drain, 12V tolerant, 60 mA sink |
| Pin 5 | RA3 — PORTA bit 3, open-drain, 12V tolerant, 60 mA sink |
| Pin 6 | RA4 — PORTA bit 4 |
| Pin 7 | RA5 — PORTA bit 5 |
| Pin 8 | OSC1/CLKIN — External clock input or crystal pin 1 |
| Pin 9 | OSC2/CLKOUT — Crystal pin 2 / clock output (4x Fosc) |
| Pin 10 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 11 | RB1 — PORTB bit 1 |
| Pin 12 | RB2 — PORTB bit 2 |
| Pin 13 | RB3 — PORTB bit 3 |
| Pin 14 | RB4 — PORTB bit 4 |
| Pin 15 | RB5 — PORTB bit 5 |
| Pin 16 | RB6 — PORTB bit 6 |
| Pin 17 | RB7 — PORTB bit 7 |
| Pin 18 | RC0 — PORTC bit 0 |
| Pin 19 | RC1 — PORTC bit 1 |
| Pin 20 | RC2 — PORTC bit 2 |
| Pin 21 | RC3 — PORTC bit 3 |
| Pin 22 | RC4 — PORTC bit 4 |
| Pin 23 | RC5 — PORTC bit 5 |
| Pin 24 | RC6 — PORTC bit 6 |
| Pin 25 | RC7 — PORTC bit 7 |
| Pin 26 | RD0 — PORTD bit 0 |
| Pin 27 | RD1 — PORTD bit 1 |
| Pin 28 | RD2 — PORTD bit 2 |
| Pin 29 | RD3 — PORTD bit 3 |
| Pin 30 | RD4 — PORTD bit 4 |
| Pin 31 | RD5 — PORTD bit 5 |
| Pin 32 | RD6 — PORTD bit 6 |
| Pin 33 | RD7 — PORTD bit 7 |
| Pin 34 | RE0 — PORTE bit 0 |
| Pin 35 | RE1 — PORTE bit 1 |
| Pin 36 | RE2 — PORTE bit 2 |
| Pin 37 | RE3 — PORTE bit 3 |
| Pin 38 | NC — No connect (reserved / not bonded on 40-PDIP variant) |
| Pin 39 | NC — No connect (reserved / not bonded on 40-PDIP variant) |
| Pin 40 | VSS — Ground reference |
| Pin 41 | VDD — +5V supply input (callout |
| Pin 42 | T0CKI — Timer 0 clock input |
| Pin 43 | RCV/TX — USART receive or transmit (per configuration) |
| Pin 44 | NC — No connect on -33/P (full 44-pin pad available on -33/L PLCC version) |
Typical Applications
PIC17C42A-33I/P is suitable for 7 applications: Industrial Motor Control, Industrial Sensor Interface & Signal Conditioning, HVAC & Building Automation, Point-of-Sale & Office Equipment Controllers, Automotive Body Electronics (Legacy 5V Systems), Security & Anti-Tamper Appliances, Educational & Prototyping Platforms.
Industrial Motor Control
The PIC17C42A-33I/P delivers 8.25 MIPS instruction throughput and a 16-bit timer/counter with 8-bit prescaler, enabling deterministic PID-loop execution for stepper and DC brush motor control in factory automation. With 33 digital I/O pins, the MCU can directly drive H-bridges, read incremental encoders, and toggle power-stage enable lines without external logic. The high-current (60 mA sink) and 12V-tolerant open-drain pins on RA2/RA3 can directly drive opto-isolated gate drivers. Per Microchip's PIC17C42A application notes, typical designs use the two analog comparators for current-zero-crossing detection in BLDC commutation. Engineers should validate thermal behavior - dissipation at 33 MHz x 8-bit core at 5V is modest but data EEPROM emulation in OTP requires software wear-leveling.
Recommended
Industrial Sensor Interface & Signal Conditioning
The PIC17C42A-33I/P's 33 I/O pins and dual analog comparators make it well-suited for multi-channel sensor aggregation in industrial instrumentation. Each comparator supports programmable reference and can trigger interrupts or capture inputs, enabling fast threshold-based event handling without CPU polling. The hardware USART supports RS-232/RS-485 bridges for sensor network outputs at up to 33 MHz core clock budget. Per Microchip datasheet section 11, the analog comparators have programmable response time and an output latch mode that simplifies zero-crossing detection in AC-line measurements. Engineers should pair the analog inputs with the internal 5V supply and route digital I/O away from analog comparators to avoid noise coupling.
Recommended
HVAC & Building Automation
Building HVAC controllers benefit from the PIC17C42A-33I/P's wide protocol support (USART, hardware interrupts on port change) and industrial temperature grade. The OTP memory prevents firmware tampering and supports anti-clone business models for OEM HVAC controllers. The 33 I/O pins handle thermostat keypads, multiple temperature sensors (NTC 10K, 100K, PT1000 via analog comparators), damper relays, and 7-segment or LCD display drivers. The 5V supply tolerance simplifies interface to legacy commercial thermostats and triac drivers. Per Microchip's PIC17 application library, sample firmware implements proportional-integral HVAC cycling with brownout-resilient VDD monitoring. Note that the obsolete lifecycle status requires careful qualification when shipping against commercial-building warranty terms.
Recommended
Point-of-Sale & Office Equipment Controllers
The PIC17C42A-33I/P's 8-bit throughput and mature toolchain make it suitable for legacy point-of-sale terminals, receipt printers, and office equipment embedded controllers. The 232 bytes of data RAM may look small by modern standards, but matches the requirements of keypad-scanning firmware, character-LCD driving, and simple UART-based peripherals. OTP memory prevents after-sale firmware tampering and protects IP for OEM equipment vendors. The PIC17's 8-level hardware stack and straightforward instruction set simplify code auditing for safety-critical commercial applications. Engineers maintaining deployed PIC17 fleets should investigate Microchip's legacy-support services for ongoing silicon supply before qualifying into new long-life equipment.
Recommended
Automotive Body Electronics (Legacy 5V Systems)
In legacy 5V automotive body-electronics architecture, the PIC17C42A-33I/P (-I industrial temp) provides reliable MCU control for seat controllers, instrument clusters, HVAC blend-door actuators, and lighting modules. The 12V tolerant high-current open-drain pins (RA2 and RA3) directly drive relay coils and incandescent lamp filaments up to 60 mA sink current - a feature inherited from PIC16 designs but rarely matched in newer 3.3V PIC18/PIC24 families. OTP memory locks firmware against ECU cloning - a critical security feature for aftermarket automotive modules. Engineers should note that automotive applications today require AEC-Q100 qualification and CAN bus integration, both of which the PIC17C42A-33I/P lacks; new designs should use PIC18F4580 or dsPIC33EP128GS702 in CAN-equipped variants.
Recommended
Security & Anti-Tamper Appliances
The PIC17C42A-33I/P's OTP memory provides inherent anti-tamper properties - the firmware cannot be read out once programmed, supporting secure access control and point-of-sale peripherals. With 33 I/O, the MCU can scan keypad matrices, drive alarm relays, monitor tamper switches, and serialize via USART to a host controller. The 8-level hardware stack limits interrupt nesting depth but matches simple security-event handling patterns. Per Microchip's OTP security guidance, all program memory cells are unreadable after programming, with no debug port exposure on production parts. For applications requiring remote firmware update over the product lifetime, the OTP device is unsuitable - choose flash-based PIC16LF877A-I/P or PIC18F4520.
Recommended
Educational & Prototyping Platforms
The PIC17C42A-33I/P is a strong teaching platform for Harvard architecture, RISC instruction sets, and 8-bit deterministic timing. With 58 single-word instructions, students can master the entire instruction set in days, and the 16-bit instruction width exposes them to wider operand handling typical of more advanced CPU cores. The 33 MHz throughput allows real-time control demos - line-following robots, simple CNC step drivers, and shift-register-driven displays. The development tooling is mature (MPLAB-ICD, PRO MATE, MPASM assembler) and abundant reference designs are documented across Microchip's education portal. For new curricula, Microchip recommends the PIC18F45K50 or PIC16F18855 as modern successors.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42A-33I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-33/PT | PIC17C42A-25E/P | PIC17C42A-25/PT | PIC17C42A-16E/P | PIC17C42A-16/P |
|---|---|---|---|---|---|---|
| Package | 40-pin PDIP | 44-pin TQFP (surface-mount) | 40-pin PDIP | 44-pin TQFP | 40-pin PDIP | 40-pin PDIP |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum Clock Frequency | 33 MHz | 33 MHz (same die) | 25 MHz (-25%) | 25 MHz | 16 MHz (-52%) | 16 MHz (-52%) |
| Program Memory Size | 4 KB OTP | 4 KB OTP (same die) | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| RAM Size | 232 bytes | 232 bytes (same die) | 232 bytes | 232 bytes | 232 bytes | 232 bytes |
| I/O Pin Count | 33 | 33 (same die) | 33 | 33 | 33 | 33 |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +125C (Extended) | 0C to +70C (Commercial) |
| Mounting Type | Through-hole (PDIP) | Surface-mount (TQFP) | Through-hole (PDIP) | Surface-mount (TQFP) | Through-hole (PDIP) | Through-hole (PDIP) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
| Qty-1 Price (approx, as of 2026-09-25) | $9.62 | $11.85 (surface-mount, less common) | $7.40 (slower speed) | $8.10 (slower, TQFP) | $5.20 (lowest speed, E temp) | $4.95 (lowest speed) |
Key Differentiators
- Highest-throughput 33 MHz in the PIC17C42A family (vs PIC17C42A-16/P)
- Higher-spec PIC17C42A vs lower-cost PIC17C42A-16 family parts (vs PIC17C42A-25E/P)
- Through-hole PDIP that simplifies hand-soldering and breadboarding (vs PIC17C42A-33/PT)
- Industrial temperature grade matches OEM-grade product expectations (vs PIC17C42A-16/P)
Design Notes
Estimated core supply current: at 33 MHz with all peripherals active and 33 I/O driving CMOS loads, ICC is approximately 20-30 mA. Decouple VDD (pin 40) and AVSS with 100 nF ceramic + 10 uF bulk within 1 cm of the package. The PIC17C42A does not have a separate AVCC - the analog comparators share VDD, so analog reference integrity depends on clean VDD filtering. Add a ferrite bead on VDD if the board-level supply has switching noise above 50 mV pk-pk.
At 33 MHz with all peripherals active, the device dissipates approximately 165 mW. PDIP-40 has theta_JA around 70 C/W, giving a junction-to-ambient rise of about 11.5 C - well within the 125 C junction limit. However, if the application operates the same package at -40C to +85C with 5V supply, the absolute stress on each OTP-programmed cell rises; design headroom of at least 30% margin on junction temperature is recommended for production longevity.
Route the OSC1/OSC2 tracks short and symmetric; place the crystal/ceramic resonator within 1 cm of the pins to minimize stray capacitance. The high-current RA2 and RA3 open-drain pins (60 mA sink) should be routed directly to the connector or driven device without series resistance to avoid voltage drop in lamp or relay applications. Place a 0.1 uF bypass capacitor on each VDD/VSS pin pair (PDIP-40 has one VDD on pin 40 and one VSS on pin 20), and an additional bulk 10 uF within 2 cm.
OTP memory cannot be erased. A single bit error in any production fuse makes the chip unusable - always validate firmware on a flash-based equivalent (e.g. PIC16LF84A in emulator mode) before committing the OTP code mask to production. Also note that the 33 I/O pins are split across PORTA-RB-RC-RD-RE with bank-switching - code writing to PORTA accesses a different register bank than code writing to PORTB without proper BANK0/BANK1 setup, which is a frequent firmware bug in legacy PIC17 code.
The high-current open-drain RA2/RA3 outputs (60 mA sink) can introduce ground bounce on the package VSS lead if multiple pins switch simultaneously. Place a 100 nF ceramic capacitor between each RA2/RA3 driver pin and the PCB ground plane near the I/O, and route the high-current return path directly to the connector rather than the PIC's VSS pin. Use slew-rate control on rising edges to limit di/dt effects on adjacent analog comparator inputs.
Compliance Information
RoHS compliance per Microchip product page. Reach compliance stated in DigiKey product listing. Not AEC-Q100 qualified - automotive applications today should use PIC18F or dsPIC family parts with AEC-Q100 grade variants.
