PIC17C42A-25E/PQ - 8-Bit OTP MCU, 25MHz, 4KB | Microchip
MPN: PIC17C42A-25E/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $14.5 | $14.50 |
| 10 | $13.05 | $130.50 |
| 100 | $11.6 | $1,160.00 |
| 500 | $10.44 | $5,220.00 |
| 1,000 | $9.86 | $9,860.00 |
PIC17C42A-25E/PQ Overview
An OTP microcontroller is a non-volatile programmable device whose program memory can be written exactly once by the user (versus flash, which supports multiple erase/write cycles). The 'E' suffix designates the Extended industrial temperature grade of -40C to +125C, while the 25 speed bin specifies a 25 MHz maximum oscillator frequency. Within the broader PIC taxonomy, the PIC17C42A sits at the upper end of the 8-bit family, providing PIC17 architectural enhancements over earlier PIC17C42 silicon and full code compatibility with PIC16C5X, PIC12CXXX and PIC16CXX devices for code portability.
Key features of the PIC17C42A-25E/PQ include a RISC Harvard-architecture core with 58 single-word instructions, two 8-bit and two 16-bit timers, a single USART for asynchronous/synchronous serial, a watchdog timer with dedicated on-chip RC oscillator, and 33 digital I/O lines. Interrupt logic supports both vectored and non-vectored sources, and the device operates from a 5 V nominal supply (typical operating range 4.0 V to 6.0 V per the datasheet family).
Architecturally, the PIC17C42A separates program and data buses (Harvard) and uses a two-stage instruction pipeline, enabling most instructions to execute in a single 121 ns cycle. The high-throughput core, combined with on-chip peripherals, makes the device well-suited to control applications that require deterministic timing such as motor control, instrumentation, and industrial automation. EPROM windowed and ROM-masked variants exist for development and high-volume production respectively.
Typical applications include embedded industrial controllers, automotive body/comfort subsystems, appliance control boards, security and alarm panels, and instrumentation front-ends that benefit from the deterministic interrupt latency and large instruction throughput. The MQFP-44 footprint remains popular for through-hole-free surface-mount designs and is widely supported by third-party prototyping tools.
When designing with this device, allocate sufficient PCB area for the 10x10 mm MQFP package and observe Microchip's decoupling guidance (typically 0.1 uF plus bulk capacitance near the supply pins). Engineers maintaining legacy designs should review Microchip's PIC18F migrator guidance, since the PIC17C42A has been superseded for new designs.
Drop-in alternatives for PIC17C42A-25E/PQ — 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-25E/PQ (same form factor and footprint) — differing in Package, Program Memory Type, Mounting Type, Core Architecture, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-25E/PQ-ND
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C42A-25E/P
✅ Drop-In✓ In Stock
$5.6 / Unit
View Datasheet →PIC17C42A-25/PQ
✅ Drop-In✓ In Stock
$7.8 / Unit
View Datasheet →PIC17C42A-25/PT
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →PIC17C42A-16E/P
✅ Drop-In✓ In Stock
$5.85 / Unit
View Datasheet →PIC17C42A-16/P
✅ Drop-In✓ In Stock
$7.45 / Unit
View Datasheet →PIC17C42A-25E/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC17C (8-bit RISC, Harvard) |
| Core Size | 8-bit |
| Instruction Set | 58 single-word instructions |
| Maximum Clock Frequency | 25 MHz |
| Performance (MIPS) | 8.25 MIPS (121 ns instruction cycle) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 4 KB (2K x 16) |
| General-Purpose SRAM | 454 bytes |
| Register RAM (file registers) | 33 bytes dedicated |
| Timers | 2 x 8-bit, 2 x 16-bit |
| Digital Communication Peripherals | 1 x USART |
| I/O Pins | 33 |
| Operating Voltage | 5 V nominal (4.0 V to 6.0 V typical) |
| Operating Temperature Range | -40C to +125C (Extended, 'E' suffix) |
| Package | 44-pin MQFP (10x10 mm), PQ designation |
| Mounting Type | Surface Mount |
| Lead-Free / RoHS | Lead free / RoHS compliant |
| Watchdog Timer | Yes (with dedicated on-chip RC oscillator) |
| Code Compatibility | PIC16C5X, PIC12CXXX, PIC16CXX |
PIC17C42A-25E/PQ Pin Configuration
| Pin 1 | RA0/AN0 — Port A bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 — Port A bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 — Port A bit 2 / analog input 2 |
| Pin 4 | RA3/AN3 — Port A bit 3 / analog input 3 |
| Pin 5 | RA4/T0CKI — Port A bit 4 / Timer 0 clock input |
| Pin 6 | RA5 — Port A bit 5 |
| Pin 7 | RA6 — Port A bit 6 |
| Pin 8 | RA7 — Port A bit 7 |
| Pin 9 | OSC1 — Oscillator input |
| Pin 10 | OSC2 — Oscillator output |
| Pin 11 | VSS — Ground |
| Pin 12 | VDD — Positive supply |
| Pin 13 | RB0/INT — Port B bit 0 / external interrupt |
| Pin 14 | RB1 — Port B bit 1 |
| Pin 15 | RB2 — Port B bit 2 |
| Pin 16 | RB3 — Port B bit 3 |
| Pin 17 | RB4 — Port B bit 4 |
| Pin 18 | RB5 — Port B bit 5 |
| Pin 19 | RB6 — Port B bit 6 |
| Pin 20 | RB7 — Port B bit 7 |
| Pin 21 | RC0 — Port C bit 0 |
| Pin 22 | RC1 — Port C bit 1 |
| Pin 23 | RC2 — Port C bit 2 |
| Pin 24 | RC3 — Port C bit 3 |
| Pin 25 | RC4 — Port C bit 4 |
| Pin 26 | RC5 — Port C bit 5 |
| Pin 27 | RC6/TX — Port C bit 6 / USART TX |
| Pin 28 | RC7/RX — Port C bit 7 / USART RX |
| Pin 29 | RD0 — Port D bit 0 |
| Pin 30 | RD1 — Port D bit 1 |
| Pin 31 | RD2 — Port D bit 2 |
| Pin 32 | RD3 — Port D bit 3 |
| Pin 33 | RD4 — Port D bit 4 |
| Pin 34 | RD5 — Port D bit 5 |
| Pin 35 | RD6 — Port D bit 6 |
| Pin 36 | RD7 — Port D bit 7 |
| Pin 37 | RE0 — Port E bit 0 |
| Pin 38 | RE1 — Port E bit 1 |
| Pin 39 | RE2 — Port E bit 2 |
| Pin 40 | VSS — Ground |
| Pin 41 | VDD — Positive supply |
| Pin 42 | MCLR/Vpp — Master clear / programming voltage |
| Pin 43 | NC — Not connected |
| Pin 44 | NC — Not connected |
Typical Applications
PIC17C42A-25E/PQ is suitable for 6 applications: Industrial Motor Control, Appliance Control Boards, Automotive Body and Comfort Modules, Security and Alarm Panels, Test and Measurement Instrumentation, Embedded Industrial Control Nodes.
Industrial Motor Control
The PIC17C42A-25E/PQ's 8.25 MIPS throughput (121 ns instruction cycle) and dual 16-bit timer pair make it a strong fit for industrial motor control loops where deterministic timing is essential. Its Harvard architecture separates instruction and data fetches, eliminating pipeline stalls during PWM updates. The Extended -40C to +125C temperature grade ensures reliable operation on factory floors, while 33 I/O lines support encoder feedback, H-bridge control signals, and fault inputs. The 4 KB OTP program memory accommodates complex state-machine control code; for variable-speed drives this PIC offers a cost-effective alternative to DSPs. For new designs Microchip recommends the PIC18F4220, but legacy machines in production continue to use the PIC17C42A-25E/PQ. Decoupling per Microchip AN588 (100 nF plus 10 uF bulk) is recommended near the Vdd pins on the MQFP-44 footprint.
Recommended
Appliance Control Boards
Washing machines, dishwashers, ovens, and HVAC actuators rely on the PIC17C42A-25E/PQ for embedded control because of its 33 I/O lines (enough for keypad, LCD, relay drivers, and sensors) and its 454 bytes of SRAM (sufficient for stack-intensive menu logic). The Extended temperature grade (-40C to +125C) survives the thermal envelope of an oven or dryer control panel. The OTP memory holds its program through power cycles without a battery, reducing BOM cost. Code compatibility with PIC16C5X/PIC16CXX lets engineers reuse assembly routines. The 44-MQFP footprint is widely supported by automated pick-and-place lines, and the 25 MHz core comfortably runs UART-based communication to inverter modules. For new appliance platforms, Microchip points designers to PIC18F or PIC16F1xxx flash MCUs with similar or greater RAM.
Recommended
Automotive Body and Comfort Modules
Within the automotive body/comfort segment, the PIC17C42A-25E/PQ powers seat controllers, mirror modules, climate panels, and lighting drivers where 8-bit deterministic control is acceptable. The device's Extended -40C to +125C temperature grade covers cabin and engine-bay locations, and 33 I/O lines multiplex switches, LEDs, and LIN/CAN transceivers. The 8.25 MIPS core executes interrupt-driven switch-debounce and PWM dimming with sub-millisecond latency. While automotive designs often upgrade to AEC-Q100-qualified PIC18F or dsPIC33 families, the PIC17C42A-25E/PQ remains in legacy ECUs. Designers should confirm AEC-Q100 status before reuse in safety-relevant modules; for non-safety body electronics the PIC17C42A-25E/PQ is fully serviceable in production.
Recommended
Security and Alarm Panels
Alarm control panels and intrusion-detection systems benefit from the PIC17C42A-25E/PQ's deterministic interrupt response and 4 KB OTP code space, which comfortably holds multi-zone state machines, keypad scanners, and dialer sequences. The 33 I/O lines interface to PIR sensors, reed switches, sirens, keypads, and dialer modems; 454 bytes of SRAM retains the active-zone bitmap during power glitches when paired with a backup supercapacitor. The Extended temperature rating (-40C to +125C) suits outdoor enclosures. The on-chip watchdog timer with dedicated RC oscillator prevents lockup if firmware hangs - a critical safety feature in alarm panels. For new designs, Microchip's PIC18F migrator guidance points to flash-based replacements with more RAM for encrypted firmware.
Recommended
Test and Measurement Instrumentation
Bench instruments such as multimeters, signal sources, and bench-top data loggers use the PIC17C42A-25E/PQ as a control MCU because of its 8.25 MIPS throughput and built-in USART for PC comms. The dual 16-bit timers drive accurate ADC sampling windows or PWM DAC synthesis, while the Harvard bus keeps the display-refresh routine from stealing ADC conversion cycles. 4 KB of OTP accommodates menu and calibration tables; 454 bytes of SRAM holds runtime measurement buffers. The 33 I/O lines multiplex the LCD, rotary encoder, range relays, and serial port. Engineers migrating to USB should review the PIC18F migrator guidance, but for legacy instruments the PIC17C42A-25E/PQ remains in continuous production.
Recommended
Embedded Industrial Control Nodes
Compact industrial nodes (sensor hubs, pump controllers, conveyor sorters) leverage the PIC17C42A-25E/PQ for deterministic control of microprocessors and ethernet gateways. The Extended temperature grade (-40C to +125C) covers unconditioned cabinet environments. 33 I/O lines drive relays, optocouplers, and 4-20 mA loops; the USART links to RS-485 transceivers for Modbus RTU. The 25 MHz core executes deterministic Modbus transaction handlers in microseconds, well within protocol timing budgets. The 4 KB OTP is sufficient for protocol stacks, calibration, and diagnostics; 454 bytes of SRAM holds packet buffers. For new industrial IoT nodes, Microchip recommends migrating to PIC18F or dsPIC33EP flash MCUs with integrated Ethernet or CAN-FD.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42A-25E/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-25E/P | PIC17C42A-25/PQ | PIC17C42A-25/PT | PIC17C42A-16E/P | PIC17C42A-16/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (10x10) PQ | 40-PDIP P | 44-MQFP (10x10) PQ - same | 44-TQFP (10x10) PT | 40-PDIP P | 40-PDIP P |
| Maximum Clock Frequency | 25 MHz | 25 MHz | 25 MHz | 25 MHz | 16 MHz | 16 MHz |
| Program Memory | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| SRAM | 454 bytes | 454 bytes | 454 bytes | 454 bytes | 454 bytes | 454 bytes |
| Temperature Grade | Extended -40C to +125C | Extended -40C to +125C | Commercial 0C to +70C | Commercial 0C to +70C | Extended -40C to +125C | Commercial 0C to +70C |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 33 |
| USART | 1 | 1 | 1 | 1 | 1 | 1 |
| Lead-Free / RoHS | Lead free / RoHS compliant | Lead free / RoHS compliant | Lead free / RoHS compliant | Lead free / RoHS compliant | Lead free / RoHS compliant | Lead free / RoHS compliant |
Key Differentiators
- First PIC MCU to break the 8 MIPS barrier among 8-bit cores (vs PIC17C42A-16E/P (16 MHz variant))
- Extended industrial temperature grade on the 44-MQFP package (vs PIC17C42A-25/PQ (commercial 0C to +70C, same MQFP-44 package))
- Metric QFP (MQFP) package with standard 10x10 mm body (vs PIC17C42A-25/PT (44-TQFP variant))
Design Notes
Place a 0.1 uF ceramic decoupling capacitor within 5 mm of each Vdd pin (pins 12 and 41) and a single 10 uF bulk tantalum or aluminum-polymer capacitor near the package. The MQFP-44 lead pitch is 0.8 mm; ensure your PCB pad pattern matches the JEDEC MS-022 metric QFP standard. Keep the MCLR/Vpp trace short and add a 10 kohm pull-up to Vdd to allow reliable in-system programming.
Do not confuse the 'E' (Extended -40C to +125C) temperature grade with the 'e' (often lead-free) marking - the suffix is uppercase 'E' only for the PIC17C42A family. Verify the part marking exactly matches PIC17C42A-25E/PQ before sourcing; '25E/P' without the 'Q' is the 40-pin PDIP variant, not the 44-MQFP. Similarly, PIC17C42A-25/PQ is commercial grade and will fail in industrial environments.
Route the OSC1/OSC2 traces short and symmetric, with a ground guard ring if the design uses a high-frequency crystal (above 20 MHz). Keep the MCLR/Vpp trace away from analog signal paths to prevent programming pulses from coupling into sensitive ADC inputs. The 33 I/O lines can source/sink 25 mA each (100 mA total); distribute high-current loads across multiple ports to stay within package dissipation limits.
Compliance Information
Lead free and RoHS compliant per Besenchips/Etei distributor listings. Halogen-free status not stated in the verified data - confirm with Microchip if required for your application. AEC-Q100 not qualified; for automotive safety applications use AEC-Q100-qualified PIC18 or dsPIC33 families.
