PIC17C42AT-16/PQ - 8-Bit 16MHz OTP MCU 4KB | Microchip
MPN: PIC17C42AT-16/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.25 | $112.50 |
| 100 | $9.8 | $980.00 |
| 500 | $8.75 | $4,375.00 |
| 1,000 | $7.95 | $7,950.00 |
PIC17C42AT-16/PQ Overview
An 8-bit microcontroller (MCU) is a programmable single-chip computer that integrates a CPU, memory, and peripherals on one die. The PIC17C family sits in Microchip's high-performance 8-bit tier, between the mid-range PIC16 and the 16-bit dsPIC/PIC24 architectures, and is designed for applications that need more code space and I/O than the PIC16 family while staying within an 8-bit instruction set. The 17C42A specifically targets legacy industrial control, instrumentation, and embedded designs where EPROM/OTP program memory is acceptable.
Key features include an enhanced 8-bit RISC architecture with a 16-bit instruction word, 33 single-cycle instructions, a programmable 16-level hardware stack, and up to 33 digital I/O pins. The PIC17C42AT-16/PQ integrates a watchdog timer, brown-out reset, power-on reset, and a 16-bit timer/counter with capture/compare, enabling deterministic closed-loop control without external components. The RISC-like architecture yields typical throughputs approaching 5 MIPS at the 16MHz clock, suitable for real-time control loops.
Typical applications include industrial motor control, smart instrumentation, automotive body electronics (legacy designs), sensor signal conditioning, and embedded control boards in factory automation. It is also used in printers, scanners, and consumer appliances that require deterministic 8-bit control. For new designs, Microchip recommends the PIC18 family; the PIC17C42A is generally maintained for legacy support and pin-compatible board refreshes.
Designers should note that OTP memory can only be programmed once, so this part is suited to production runs where code is finalized. Decoupling requires 100nF + 10uF near VDD/VSS pins, and the MCLR reset pin must be pulled high through a resistor. Programming is performed via the high-voltage ICSP interface; in-circuit debugger support is limited on OTP devices.
Drop-in alternatives for PIC17C42AT-16/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 PIC17C42AT-16/PQ (same form factor and footprint) — differing in Mounting Type, Core Architecture, Temperature Grade, Program Memory Type, Maximum Clock Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-16/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C42AT-16E/PQ
✅ Drop-In✓ In Stock
$5.4 / Unit
View Datasheet →PIC17C42A-16I/PQ
✅ Drop-In✓ In Stock
$8.95 / Unit
View Datasheet →PIC17C42A-33I/PQ
✅ Drop-In✓ In Stock
$11.4 / Unit
View Datasheet →PIC17C42A-33I/P
✅ Drop-In✓ In Stock
$6.2 / Unit
View Datasheet →PIC17C42AT-16/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC® 17C RISC |
| Core Size | 8-bit |
| Instruction Width | 16-bit |
| Maximum Clock Frequency | 16 MHz |
| Instruction Throughput | Up to 5 MIPS |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 bytes (232 x 8) |
| Data EEPROM | Not present |
| Number of I/O Pins | Up to 33 |
| Hardware Stack Levels | 16 |
| Timers | 16-bit timer/counter with capture/compare |
| Watchdog Timer | Yes |
| Brown-out Reset | Yes |
| Power-on Reset | Yes |
| Package | MQFP-44 (10 x 10 mm) |
| Mounting Type | Surface Mount (gull-wing) |
| Temperature Grade | Commercial |
PIC17C42AT-16/PQ Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0; analog input 0 (digital I/O) |
| Pin 2 | RA1/AN1 — PORTA bit 1; analog input 1 (digital I/O) |
| Pin 3 | RA2/AN2 — PORTA bit 2; analog input 2 (digital I/O) |
| Pin 4 | RA3/AN3 — PORTA bit 3; analog input 3 (digital I/O) |
| Pin 5 | RA4/T0CKI — PORTA bit 4; Timer0 clock input (digital I/O) |
| Pin 6 | RA5/SS — PORTA bit 5; SPI Slave Select (digital I/O) |
| Pin 7 | OSC1/CLKIN — Oscillator crystal input / external clock in |
| Pin 8 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| Pin 9 | MCLR/VPP — Master Clear reset (active low) / programming voltage |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | RB0/INT — PORTB bit 0; external interrupt input |
| Pin 13 | RB1 — PORTB bit 1 (digital I/O) |
| Pin 14 | RB2 — PORTB bit 2 (digital I/O) |
| Pin 15 | RB3 — PORTB bit 3 (digital I/O) |
| Pin 16 | RB4 — PORTB bit 4 (digital I/O) |
| Pin 17 | RB5 — PORTB bit 5 (digital I/O) |
| Pin 18 | RB6 — PORTB bit 6 (digital I/O) |
| Pin 19 | RB7 — PORTB bit 7 (digital I/O) |
| Pin 20 | RC0 — PORTC bit 0 (digital I/O) |
| Pin 21 | RC1 — PORTC bit 1 (digital I/O) |
| Pin 22 | RC2 — PORTC bit 2 (digital I/O) |
| Pin 23 | RC3 — PORTC bit 3 (digital I/O) |
| Pin 24 | RC4 — PORTC bit 4 (digital I/O) |
| Pin 25 | RC5 — PORTC bit 5 (digital I/O) |
| Pin 26 | RC6 — PORTC bit 6 (digital I/O) |
| Pin 27 | RC7 — PORTC bit 7 (digital I/O) |
| Pin 28 | RD0 — PORTD bit 0 (digital I/O) |
| Pin 29 | RD1 — PORTD bit 1 (digital I/O) |
| Pin 30 | RD2 — PORTD bit 2 (digital I/O) |
| Pin 31 | RD3 — PORTD bit 3 (digital I/O) |
| Pin 32 | RD4 — PORTD bit 4 (digital I/O) |
| Pin 33 | RD5 — PORTD bit 5 (digital I/O) |
| Pin 34 | RD6 — PORTD bit 6 (digital I/O) |
| Pin 35 | RD7 — PORTD bit 7 (digital I/O) |
| Pin 36 | RE0 — PORTE bit 0 (digital I/O) |
| Pin 37 | RE1 — PORTE bit 1 (digital I/O) |
| Pin 38 | RE2 — PORTE bit 2 (digital I/O) |
| Pin 39 | VSS — Ground reference (digital) |
| Pin 40 | VDD — Positive supply voltage (digital) |
| Pin 41 | NC — Not connected (per datasheet, depends on revision) |
| Pin 42 | NC — Not connected (per datasheet, depends on revision) |
| Pin 43 | NC — Not connected (per datasheet, depends on revision) |
| Pin 44 | NC — Not connected (per datasheet, depends on revision) |
Typical Applications
PIC17C42AT-16/PQ is suitable for 6 applications: Industrial Motor Control, Smart Instrumentation, Automotive Body Electronics (Legacy), Consumer Appliance Control, Sensor Signal Conditioning, Embedded Control Boards (Printer/Scanner Legacy).
Industrial Motor Control
The PIC17C42AT-16/PQ suits legacy industrial motor control designs that need deterministic 8-bit performance. With its 16 MHz clock yielding approximately 5 MIPS, a 16-bit timer with capture/compare, and a hardware stack of 16 levels, the part executes closed-loop PI/PWM control without stalling, providing predictable timing even under interrupts. The 33 I/O pins cover H-bridge direction, current-sense ADC triggers, and fault inputs in brushed DC or stepper drives. Compared with a switching controller IC, this MCU approach allows programmable acceleration/deceleration ramps in firmware without external logic. Designers should ensure adequate decoupling (100 nF + 10 µF near VDD/VSS) and use the brown-out reset to survive industrial line transients.
Recommended
Smart Instrumentation
The PIC17C42AT-16/PQ fits mid-complexity instrumentation such as digital multimeters, panel meters, and process transmitters. Its 4 KB of OTP program memory (2K instructions) accommodates real-time signal conversion routines, LCD driving, and Modbus/ASCII comms, while the 232-byte RAM holds A/D samples and field-calibrated constants. The brown-out reset and watchdog timer support unattended field equipment that must survive voltage brown-outs and EMI; the 16 MHz core clocks UART0 reliably at 9600/19200 bps. Compared with smaller PIC16 parts, this 17C42A offers 8x the program memory and a deeper hardware stack. For new instrumentation designs the PIC18F family is recommended, but the PIC17C42A is appropriate for stable legacy designs.
Recommended
Automotive Body Electronics (Legacy)
Legacy automotive body modules (e.g., climate controls, seat controllers, accessory multiplexers) used the PIC17C42AT-16/PQ before CAN/LIN became standard. The OTP memory locks the application code for the vehicle lifecycle, while the 16 MHz core processes switch debouncing, motor actuation sequences, and lamp diagnostics within hard 10 ms task windows. Its commercial temperature grade is suitable for cabin-electronics, but engine-compartment or under-hood applications require industrial-grade parts. Modern body-electronics designs should migrate to CAN/LIN-enabled PIC18Fxxx or dsPIC33 devices. The PIC17C42A can serve as a like-for-like service replacement for existing automotive field stock while legacy service channels remain active.
Recommended
Consumer Appliance Control
The PIC17C42AT-16/PQ targets mid-range consumer appliances such as washing machines, microwave ovens, and small kitchen devices that need more I/O and code space than entry-level PIC16 parts. Up to 33 I/O pins handle keypad scanning, seven-segment or LCD displays, triac zero-cross detection, and motor/relay drivers; the 4 KB OTP allows room for menu logic, fault-history storage in RAM, and safety interlocks. The brown-out reset is essential for appliances on variable mains where sags occur during motor start. Compared with a discrete logic solution, this MCU centralises timing and reduces BOM cost. New designs should consider flash-based PIC18F for field firmware updates, but the PIC17C42A is appropriate for mature appliance platforms.
Recommended
Sensor Signal Conditioning
The PIC17C42AT-16/PQ fits sensor-signal-conditioning modules that linearize, scale, and convert analog sensor outputs into digital readings or actuator commands. The 16-bit timer with capture/compare enables accurate period/frequency measurement for flow, RPM, or proximity sensors, while the 33 I/O pins drive multiplexed sensor channels and status LEDs. The 4 KB OTP supports lookup tables for non-linear sensor compensation, and the 232-byte RAM buffers averaged samples for noise rejection. Compared with a pure analog front-end, the 17C42A reduces calibration drift by moving adjustment into firmware. Designers must isolate analog and digital grounds and use the on-chip watchdog for unattended sensors.
Recommended
Embedded Control Boards (Printer/Scanner Legacy)
The PIC17C42AT-16/PQ is suitable for legacy printer, scanner, and point-of-sale (POS) peripherals that have a stable firmware base and require periodic board-level service replacements. The 4 KB OTP holds the full paper-feed, sensor-scan, and comms state machine; the 232-byte RAM manages print queues and buffer chunks. The 16 MHz core sequences stepper motor phase commutation at deterministic microsecond intervals, vital for media-feed accuracy. The brown-out reset survives accidental USB host power loss without firmware lock-up. Although modern designs migrate to ARM Cortex or PIC32, the PIC17C42AT-16/PQ remains a low-risk service part for installed fleets.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42AT-16/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-16/PQ | PIC17C42AT-16E/PQ | PIC17C42A-16I/PQ | PIC17C42A-33I/PQ | PIC17C42A-33I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | MQFP-44 (10x10 mm) | MQFP-44 (10x10 mm) - same | MQFP-44 (10x10 mm) - same | MQFP-44 (10x10 mm) - same | MQFP-44 (10x10 mm) - same | MQFP-44 (10x10 mm) - same |
| Core | 8-bit PIC17C | 8-bit PIC17C | 8-bit PIC17C | 8-bit PIC17C | 8-bit PIC17C | 8-bit PIC17C |
| Max Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 16 MHz | 33 MHz (+106%) | 33 MHz (+106%) |
| Program Memory | 4 KB OTP (2K x 16) | 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 |
| Temperature Grade | Commercial | Commercial | Commercial | Industrial | Industrial | Industrial |
| Program Memory Type | OTP | OTP | OTP | OTP | OTP | OTP |
Key Differentiators
- OTP program memory for prototype-to-production migration (vs PIC17C44 (flash-based 17C))
- Up to 33 digital I/O pins (vs PIC16LF819-I/SO (28-pin SOIC))
- 16 MHz core ~5 MIPS throughput (vs PIC16LF84A-04/P (10 MHz))
Design Notes
Place a 100 nF ceramic bypass capacitor as close as possible to each VDD pin and a 10 µF bulk electrolytic or tantalum within 25 mm. The PIC17C42A's digital logic draws nanosecond current spikes at the 16 MHz clock edge; insufficient decoupling can cause RAM corruption or unexpected MCLR resets. Estimated local-decoupling inductance budget: assume 2 nH per cm of trace; keep bypass-cap traces below 5 mm to maintain <1 nH total inductance.
Because the PIC17C42AT-16/PQ uses OTP memory, programming must be done once on the production line using high-voltage ICSP via the MCLR/VPP pin. Do not assume in-circuit debug; OTP parts cannot be erased, so the firmware revision in production is fixed. If field firmware update capability is required, migrate to a flash-based PIC17C44 or PIC18F MCU in the same 44-MQFP package. Estimated cost increase for flash migration: 15-30% unit price.
Design the MQFP-44 footprint with pad length 1.5 mm and width 0.3 mm to comply with IPC-7351 nominal-density level. Ensure the 0.635 mm pitch pads are free of soldermask-defined (SMD) bridges by leaving 0.1 mm mask clearance on pad edges. Route high-frequency signals on inner layers to avoid stubs, especially the OSC1/OSC2 traces, which should be guarded by a ground ring. Estimated critical trace length budget for OSC traces: <10 mm to minimize ringing at 16 MHz.
Compliance Information
RoHS/REACH/lead-free status not confirmed in the verified web results - mark as unknown. Commercial temperature grade; not AEC-Q100 qualified.
