PIC17C42A-33E/P - 33MHz 8-bit OTP MCU, 4KB, 40-PDIP | Microchip
MPN: PIC17C42A-33E/P ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.95 | $8.95 |
| 10 | $7.85 | $78.50 |
| 100 | $6.2 | $620.00 |
| 500 | $5.4 | $2,700.00 |
| 1,000 | $4.85 | $4,850.00 |
PIC17C42A-33E/P Overview
A microcontroller (MCU) is a single-chip computer that combines a CPU core, non-volatile program memory, working RAM, and peripheral blocks such as timers, communications interfaces and analog converters. The PIC17C42A sits inside the 8-bit MCU category, beneath Microchip's 16-bit PIC24 and dsPIC families and far below the 32-bit PIC32 line. Within the PIC17C sub-family it is the entry-level OTP die, making it a stepping stone between the baseline PIC16C5X/PIC16CXX devices and the higher-pin-count PIC17C43/44 members.
Key features include 8.25 MIPS peak throughput (121 ns instruction cycle), 33 MHz maximum clock, 4 KB OTP program memory organised as 2K x 16, 232 bytes of general-purpose RAM, 33 I/O pins, hardware USART, PWM module, watchdog timer with its own on-chip RC oscillator, and selectable oscillator options (external clock or crystal/resonator). The extended ('E') temperature grade supports -40C to +125C operation, suitable for industrial environments.
Technically, the PIC17C42A uses a 16-bit instruction word with an 8-bit data path, a 16-level hardware stack, and a vectored interrupt controller. Its OTP EPROM cell allows one-time programming in volume production; in-circuit programming is not supported because there is no flash. Designers should therefore plan for a pre-programmed, socketed part or a UV-erasable windowed variant (PIC17C42A with JW package) during development.
Typical applications include industrial control boards, motor drive front-ends (using the PWM module), UART-linked sensor hubs, white-goods and appliance controllers, and legacy embedded designs migrating from PIC16C5X to a higher-performance RISC core. The wide temperature range makes it suitable for outdoor or automotive under-hood subsystems where extended-grade parts are required.
When designing with this part, pay attention to oscillator selection: an external clock or crystal/resonator must be supplied because the PIC17C42A has no internal oscillator. Programming requires a Microchip-supported device programmer because OTP memory cannot be re-programmed in circuit, and production units must be sourced pre-programmed or programmed by a Microchip programming partner.
This page synthesizes distributor pricing, drop-in alternative listings (including the recommended PIC18F4220 migration path), and practical design notes that are not collected in a single place in the manufacturer datasheet.
Drop-in alternatives for PIC17C42A-33E/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-33E/P (same form factor and footprint) — differing in Package, Core Architecture, Program Memory Type, Mounting Type, RAM Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-33/PT
✅ Drop-In✓ In Stock
$9.65 / Unit
View Datasheet →PIC17C42A-16E/P
✅ Drop-In✓ In Stock
$5.85 / Unit
View Datasheet →PIC17C42A-25E/P
✅ Drop-In✓ In Stock
$5.6 / Unit
View Datasheet →PIC17C42A-25/PT
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →PIC17C42A-16/P
✅ Drop-In✓ In Stock
$7.45 / Unit
View Datasheet →PIC17C42AT-33I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C42A-33E/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC17C |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes |
| Maximum Clock Frequency | 33 MHz |
| Instruction Throughput | 8.25 MIPS (121 ns/instruction) |
| Number of I/O Pins | 33 |
| Package | 40-pin PDIP (through-hole) |
| Temperature Grade | Extended (-40C to +125C) |
| Connectivity | UART/USART |
| Peripherals | POR, PWM, WDT |
| Oscillator Type | External (crystal/resonator/clock) |
| Data Bus Width | 8-bit |
| Instruction Word Width | 16-bit |
| Packaging | Tube |
| Mounting Type | Through-Hole |
PIC17C42A-33E/P Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 5 | RA3/AN3 — PORTA bit 3 / analog input 3 |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/SS — PORTA bit 5 / SPI slave select |
| Pin 8 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 9 | RB1 — PORTB bit 1 |
| Pin 10 | RB2 — PORTB bit 2 |
| Pin 11 | VDD — Positive supply |
| Pin 12 | VSS — Ground |
| Pin 13 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 14 | OSC2/CLKOUT — Oscillator output |
| Pin 15 | RC0/T1CKI — PORTC bit 0 / Timer1 clock input |
| Pin 16 | RC1/CCP2 — PORTC bit 1 / Capture/Compare/PWM 2 |
| Pin 17 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM 1 |
| Pin 18 | RC3 — PORTC bit 3 |
| Pin 19 | RD0 — PORTD bit 0 |
| Pin 20 | RD1 — PORTD bit 1 |
| Pin 21 | RD2 — PORTD bit 2 |
| Pin 22 | RD3 — PORTD bit 3 |
| Pin 23 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 24 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 25 | RC6/TX/CK — PORTC bit 6 / USART TX / clock |
| Pin 26 | RC7/RX/DT — PORTC bit 7 / USART RX / data |
| Pin 27 | RD4 — PORTD bit 4 |
| Pin 28 | RD5 — PORTD bit 5 |
| Pin 29 | RD6 — PORTD bit 6 |
| Pin 30 | RD7 — PORTD bit 7 |
| Pin 31 | RE0/AN5 — PORTE bit 0 / analog input 5 |
| Pin 32 | RE1/AN6 — PORTE bit 1 / analog input 6 |
| Pin 33 | RE2/AN7 — PORTE bit 2 / analog input 7 |
| Pin 34 | AVDD — Analog supply |
| Pin 35 | AVSS — Analog ground |
| Pin 36 | NC — Not connected (per datasheet) |
| Pin 37 | NC — Not connected (per datasheet) |
| Pin 38 | NC — Not connected (per datasheet) |
| Pin 39 | NC — Not connected (per datasheet) |
| Pin 40 | NC — Not connected (per datasheet) |
Typical Applications
PIC17C42A-33E/P is suitable for 6 applications: Industrial Control Boards, Motor Drive Front-End, UART-Linked Sensor Hub, White-Goods and Appliance Controllers, Legacy Embedded Upgrade Path, Automotive Under-Hood Subsystems.
Industrial Control Boards
The PIC17C42A-33E/P's 33 MHz throughput and 33 I/O pins make it well-suited for industrial control boards that read pushbuttons, drive relays and coordinate multiple subsystems. Its extended (-40C to +125C) temperature grade ensures stable operation in factory cabinets, near motors and in outdoor enclosures. The on-chip PWM module generates actuator control signals, while the hardware USART links the board to a master PLC or HMI display. Compared with a discrete logic design, this single-chip approach reduces PCB area, BOM count and EMI susceptibility while delivering deterministic 121 ns instruction timing.
Recommended
Motor Drive Front-End
In a motor drive front-end the PIC17C42A-33E/P generates PWM signals for an H-bridge power stage and reads back encoder feedback through its digital I/O. The 8.25 MIPS throughput and 121 ns instruction cycle are sufficient to compute velocity PI loops at switch rates up to several kHz. Its hardware PWM module supports centre-aligned or edge-aligned modes, and the watchdog timer with its own RC oscillator catches firmware lockups that could otherwise drive the motor into a stall. Industrial-grade temperature operation suits motor enclosures that experience self-heating.
Recommended
UART-Linked Sensor Hub
A UART-linked sensor hub aggregates readings from multiple serial sensors and forwards them to a host processor over RS-232/RS-485. The PIC17C42A-33E/P provides a hardware USART that handles framing, baud-rate generation and error detection without software overhead, freeing the CPU to poll sensors and run application logic. Its 232 bytes of RAM buffer incoming sensor frames, while the 33 I/O pins accept digital sensors and bit-banged peripherals. The wide temperature range supports outdoor sensor installations and under-hood automotive sensor aggregation.
Recommended
White-Goods and Appliance Controllers
Washing machines, dishwashers and HVAC controllers have long used PIC17C42A-33E/P as the main MCU for sequencing pumps, valves and user-interface keypads. The OTP EPROM locks in the appliance firmware at production, preventing field tampering and ensuring deterministic boot behaviour. With 33 I/O pins the device directly drives 7-segment displays, relay coils and triac interfaces without external mux logic. Extended temperature operation tolerates the elevated ambient inside appliance housings. Migrating to PIC18F4220 preserves the development model while adding flash reprogrammability for service updates.
Recommended
Legacy Embedded Upgrade Path
Designers migrating from PIC16C5X/PIC16CXX to a higher-performance RISC core often step through the PIC17C42A-33E/P. It is upwards-compatible at the architectural level and offers 4 KB of OTP plus 232 bytes of RAM - enough headroom for typical 8-bit embedded applications. The 40-pin PDIP footprint matches existing board layouts, while 33 MHz operation delivers nearly 4x the throughput of legacy PIC16C5X parts. For new designs, Microchip recommends PIC18F4220 directly; the PIC17C42A family remains relevant for sustaining legacy products with proven firmware.
Recommended
Automotive Under-Hood Subsystems
Extended-grade PIC17C42A-33E/P parts are specified for -40C to +125C, which covers automotive under-hood environments. The MCU can monitor coolant-temperature sensors, drive fan relays and orchestrate auxiliary HVAC actuators with predictable real-time behaviour thanks to its deterministic 121 ns instruction cycle. The 33 MHz clock plus hardware PWM handles brushed-DC motor speed control for small fans and pumps. Note: this part is not AEC-Q100 qualified - for full automotive qualification, migrate to PIC18F4220 (AEC-Q100 variants exist).
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42A-33E/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-33/PT | PIC17C42A-16E/P | PIC17C42A-25E/P | PIC17C42A-25/PT | PIC17C42A-16/P | PIC17C42AT-33I/PT |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 40-PDIP | 44-TQFP (PT) | 40-PDIP - same | 40-PDIP - same | 44-TQFP (PT) | 40-PDIP - same | 44-TQFP (PT) |
| Maximum Clock | 33 MHz | 33 MHz - same | 16 MHz (-52%) | 25 MHz (-24%) | 25 MHz (-24%) | 16 MHz (-52%) | 33 MHz - same |
| Program Memory | 4 KB OTP | 4 KB OTP - same | 4 KB OTP - same | 4 KB OTP - same | 4 KB OTP - same | 4 KB OTP - same | 4 KB OTP - same |
| Temperature Grade | Extended -40C to +125C | Commercial 0C to +70C | Extended -40C to +125C - same | Extended -40C to +125C - same | Commercial 0C to +70C | Commercial 0C to +70C | Industrial -40C to +85C |
| Mounting | Through-hole | Surface mount (TQFP) | Through-hole - same | Through-hole - same | Surface mount (TQFP) | Through-hole - same | Surface mount (TQFP) |
| RAM | 232 x 8 bytes | 232 x 8 bytes - same | 232 x 8 bytes - same | 232 x 8 bytes - same | 232 x 8 bytes - same | 232 x 8 bytes - same | 232 x 8 bytes - same |
| Connectivity | UART/USART | UART/USART - same | UART/USART - same | UART/USART - same | UART/USART - same | UART/USART - same | UART/USART - same |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Highest clock grade in the PIC17C42A family (vs PIC17C42A-25E/P)
- Extended temperature grade (-40C to +125C) (vs PIC17C42A-16/P)
- Through-hole PDIP footprint for legacy boards (vs PIC17C42A-33/PT)
- Largest I/O count among PIC17C42A family (vs PIC16C5X legacy parts)
Design Notes
The PIC17C42A die has no internal oscillator. Designs that leave OSC1/OSC2 floating or that route a slow RC network to a 33 MHz target will fail to start or run erratically. For 33 MHz operation the configuration fuse must select the HS oscillator mode and a fundamental-mode crystal or third-overtone network must be sized per the Microchip PIC17C4X datasheet (DS30412C) oscillator table.
Place the decoupling capacitor (typically 0.1 uF ceramic) within 5 mm of the VDD/VSS pins. Add a bulk 10 uF tantalum or aluminium electrolytic capacitor near the MCU supply rail. The MCLR pin must be pulled up to VDD through a 10 kohm resistor with a 100 nF capacitor to ground to filter noise and provide a clean reset during power-up.
Because the PIC17C42A is OTP EPROM, any firmware bug shipped to production cannot be patched in the field. For prototype and low-volume runs, use the JW (windowed) package variant so UV erasure allows code iteration. For production units, lock the configuration bits and verify code with the MPLAB simulator before committing to OTP programming.
At 33 MHz the PIC17C42A-33E/P draws approximately 15-20 mA from VDD. With the extended temperature grade rated to +125C, ensure the ambient inside the enclosure stays within this limit - particularly in motor-drive or relay-dense designs where neighbouring components radiate heat. The 40-pin PDIP package has no exposed thermal pad, so heatsinking is not feasible; rely on ambient control and reduced duty-cycle firmware patterns instead.
Compliance Information
Compliance data not present in the verified web sources. Per Microchip's product page the PIC17C42A family is marked obsolete; original PDIP-40 production units were typically lead-free but full material compliance must be confirmed with the distributor lot. Not AEC-Q100 qualified - automotive applications should migrate to PIC18F4220-I/P variants.
