PIC17C42A-16I/L - 8-bit 16MHz OTP MCU, 4KB | Microchip
MPN: PIC17C42A-16I/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $13.85 | $1,385.00 |
| 500 | $11.4 | $5,700.00 |
| 1,000 | $9.95 | $9,950.00 |
PIC17C42A-16I/L Overview
What is a microcontroller (MCU)? An MCU is a single-chip computer that integrates a CPU core, non-volatile program memory (ROM/EPROM/Flash/OTP), working RAM, and peripheral interfaces (GPIO, timers, UART, ADC, etc.) into one package. PIC17C4X parts sit in Microchip's "high-performance 8-bit" tier, between the mid-range PIC16 family and the 16-bit dsPIC/PIC24 families, and are part of the broader power-management-and-embedded-control semiconductor category.
Key features include a RISC instruction set with only 58 single-word instructions (all single-cycle, 121 ns, except program branches and table reads/writes which are two-cycle), a 16-level hardware stack, a hardware multiply unit, two 8-bit timer/counters, and one 16-bit timer/counter with capture/compare. The 16I industrial-grade temperature range (-40 °C to +85 °C) and OTP program memory make it well suited for low-volume production runs and field-proven designs.
The PIC17C42A uses a Harvard-architecture CPU with separate program and data buses, an 8-bit ALU with a hardware multiply (8 × 8 in one cycle), and a 16-bit-wide program word. The 121 ns instruction execution at 33 MHz oscillator allows deterministic interrupt response and tight control loops, distinguishing it from CISC 8-bit MCUs of the same vintage.
Typical applications include industrial control subsystems, motor-control front-ends, instrumentation, smart sensors, automotive body/comfort ECUs (non-safety), and legacy embedded products ported from PIC16 designs that require more code space, more RAM, or more I/O. The 4 KB OTP and 232 B RAM are sized for moderate protocol stacks and state machines.
When designing with this part, account for OTP (one-time-programmable) limitations: firmware must be fully verified before programming. Also note Microchip's recommendation that newer designs use the PIC18F4220 as the modern functional successor. The PLCC-44 socket footprint allows in-system programming with standard tools.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC17C42A-16I/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-16I/L (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, RAM Size, Operating Temperature Range, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C43-16I/L
✅ Drop-In✓ In Stock
$11.1 / Unit
View Datasheet →PIC17C42AT-16I/L
✅ Drop-In✓ In Stock
$10.95 / Unit
View Datasheet →PIC17C42A-16E/L
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$9.95 / Unit
View Datasheet →PIC17C42A-16/L
✅ Drop-In✓ In Stock
$8.3 / Unit
View Datasheet →PIC17C44-16I/L
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$6.15 / Unit
View Datasheet →PIC17C42A-16I/L Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Series | PIC® 17C |
| Core | PIC 8-bit RISC |
| Instruction Set Width | 16-bit (single-word instructions) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 4 KB (2K × 16) |
| RAM Size | 232 × 8 bytes (232 B) |
| Number of I/O Pins | 33 |
| Maximum Clock Frequency | 33 MHz oscillator input |
| CPU Speed (Instruction Cycle) | 16 MHz, 121 ns instruction cycle |
| Throughput | 8.25 MIPS |
| Number of Instructions | 58 |
| Hardware Stack Levels | 16 |
| Hardware Multiplier | Yes (8 × 8 in one cycle) |
| Timers | Two 8-bit + one 16-bit with capture/compare |
| Operating Supply Voltage | 4.5 V to 6 V |
| Operating Temperature | -40 °C to +85 °C (Industrial, "I") |
| Package / Case | 44-LCC (J-Lead), 16.59 × 16.59 mm ("L" suffix) |
| Mounting Type | Surface Mount |
| Oscillator Type | External |
| Packaging | Tube |
PIC17C42A-16I/L Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0 — Port A bit 0 (digital I/O) |
| Pin 3 | RA1 — Port A bit 1 (digital I/O) |
| Pin 4 | RA2 — Port A bit 2 (digital I/O) |
| Pin 5 | RA3 — Port A bit 3 (digital I/O) |
| Pin 6 | RA4 — Port A bit 4 (digital I/O, open-drain option) |
| Pin 7 | RA5 — Port A bit 5 (digital I/O) |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1 — Oscillator input (external clock or crystal) |
| Pin 10 | OSC2 — Oscillator output (crystal drive) |
| Pin 11 | VDD — Positive supply (4.5 V to 6 V) |
| Pin 12 | RB0 — Port B bit 0 (digital I/O, INT0) |
| Pin 13 | RB1 — Port B bit 1 (digital I/O, INT1) |
| Pin 14 | RB2 — Port B bit 2 (digital I/O) |
| Pin 15 | RB3 — Port B bit 3 (digital I/O) |
| Pin 16 | RB4 — Port B bit 4 (digital I/O) |
| Pin 17 | RB5 — Port B bit 5 (digital I/O) |
| Pin 18 | RB6 — Port B bit 6 (digital I/O, programming clock) |
| Pin 19 | RB7 — Port B bit 7 (digital I/O, programming data) |
| Pin 20 | VSS — Ground reference |
| Pin 21 | RC0 — Port C bit 0 (digital I/O, T0CKI timer0 clock) |
| Pin 22 | RC1 — Port C bit 1 (digital I/O, CCP2 capture/compare) |
| Pin 23 | RC2 — Port C bit 2 (digital I/O, CCP1 capture/compare) |
| Pin 24 | RC3 — Port C bit 3 (digital I/O) |
| Pin 25 | RC4 — Port C bit 4 (digital I/O, SDI/SPI input) |
| Pin 26 | RC5 — Port C bit 5 (digital I/O, SDO/SPI output) |
| Pin 27 | RC6 — Port C bit 6 (digital I/O, TX/async transmit) |
| Pin 28 | RC7 — Port C bit 7 (digital I/O, RX/async receive) |
| Pin 29 | VSS — Ground reference |
| Pin 30 | RD0 — Port D bit 0 (digital I/O) |
| Pin 31 | RD1 — Port D bit 1 (digital I/O) |
| Pin 32 | RD2 — Port D bit 2 (digital I/O) |
| Pin 33 | RD3 — Port D bit 3 (digital I/O) |
| Pin 34 | RD4 — Port D bit 4 (digital I/O) |
| Pin 35 | RD5 — Port D bit 5 (digital I/O) |
| Pin 36 | RD6 — Port D bit 6 (digital I/O) |
| Pin 37 | RD7 — Port D bit 7 (digital I/O) |
| Pin 38 | VDD — Positive supply (4.5 V to 6 V) |
| Pin 39 | VSS — Ground reference |
| Pin 40 | NC — Not connected (per datasheet) |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC17C42A-16I/L is suitable for 6 applications: Industrial Control Subsystems, Motor Control Front-End, Smart Sensor Hub, Instrumentation Front-End, Automotive Body/Comfort ECU, Legacy Embedded Product Maintenance.
Industrial Control Subsystems
The PIC17C42A-16I/L fits industrial control subsystems because of its 8.25 MIPS throughput (121 ns instruction cycle) and 33 digital I/O pins, which together can scan multiple sensor inputs, drive actuators, and execute a deterministic control loop at millisecond cadence. The 4 KB OTP program memory holds small state-machine or PID-firmware images, while the 232-byte RAM retains run-time variables for filter coefficients, setpoints, and debounce buffers. The 16-bit timer with capture/compare enables precise pulse-width measurement or PWM generation for motor-control front-ends. Industrial temperature rating (-40 °C to +85 °C) and 4.5–6 V supply tolerance align with 5 V industrial backplanes.
Recommended
Motor Control Front-End
The PIC17C42A-16I/L is well suited for brushed DC and stepper motor control front-ends because its 16-bit timer/counter with capture and compare can synthesize PWM at carrier frequencies up to ~40 kHz while the 8-bit timers handle quadrature decoding or tachometer sampling. With 33 I/O pins, the MCU can drive multi-axis H-bridges, fault-input lines, and a serial command port from a single chip. The 4 KB OTP is enough for a FOC or trapezoidal commutation table plus PID controller, and 232 bytes of RAM is sufficient for current/torque loop state variables. The 121 ns deterministic instruction cycle simplifies latency analysis for real-time control law execution.
Recommended
Smart Sensor Hub
The PIC17C42A-16I/L acts as a smart sensor hub because of its 33 GPIO pins, which can host multiple SPI/I2C sensor buses (thermistor strings, pressure transducers, accelerometers) using software bit-banging or hardware peripherals. The 4 KB OTP accommodates sensor-fusion or linearization firmware, while 232 bytes of RAM holds calibration tables and sample buffers. The hardware 8 × 8 multiplier accelerates digital-filter operations on raw sensor data. Industrial -40 °C to +85 °C rating suits outdoor or factory-floor sensor enclosures, and the 16 MHz core allows sampling at rates sufficient for vibration or acoustic emission analysis without an external DSP.
Recommended
Instrumentation Front-End
The PIC17C42A-16I/L serves as an instrumentation front-end MCU because its 121 ns instruction cycle provides the throughput needed to perform digital averaging, calibration lookup, and serial output for measurement instruments such as digital panel meters, benchtop multimeters, or process calibrators. With 33 I/O pins, the device can scan a 4×4 keypad, drive an LCD, multiplex multiple display digits, and maintain a UART/SCI channel to a host PC. The 4 KB OTP holds measurement routines and menu-driven firmware, while 232 bytes of RAM is adequate for sample averaging buffers. The industrial temperature grade supports laboratory and field calibration environments.
Recommended
Automotive Body/Comfort ECU
The PIC17C42A-16I/L has historically been used in non-safety automotive body-comfort ECUs such as seat controllers, mirror adjusters, HVAC blend doors, and lighting modules because of its 33 GPIO (which can drive multi-channel PWM for seat positioning), 16-bit timer with capture/compare (for debounced switch input timing), and industrial temperature rating that covers cabin environments. The 4 KB OTP holds comfort-control firmware including learned-position memory in RAM. Note: the part lacks AEC-Q100 qualification and is not recommended for new automotive designs; for new programs, use PIC18F family AEC-Q100-qualified parts. Use of the legacy PIC17C42A-16I/L in new automotive applications is not advised.
Recommended
Legacy Embedded Product Maintenance
The PIC17C42A-16I/L is used to maintain or repair field-deployed legacy embedded products that were designed around this part before flash-based MCUs became standard. Because the MCU is OTP (one-time-programmable), repair service depots must keep verified blank inventory to replace failed units. The 4 KB OTP and 232-byte RAM match the original firmware image exactly, ensuring the rebuilt board boots the same code that has been qualified for years. The PLCC-44 socket allows quick field replacement. The 16 MHz core reproduces the original timing and I/O behavior bit-for-bit. This application is the primary reason the part remains commercially listed despite its obsolete lifecycle status.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42A-16I/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C43-16I/L | PIC17C42AT-16I/L | PIC17C42A-16E/L | PIC17C42A-16/L | PIC17C44-16I/L |
|---|---|---|---|---|---|---|
| Package | 44-PLCC (J-Lead, "L") | 44-PLCC (J-Lead, "L") - same | 44-PLCC (J-Lead, "L") - same | 44-PLCC (J-Lead, "L") - same | 44-PLCC (J-Lead, "L") - same | 44-PLCC (J-Lead, "L") - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (OTP) | 4 KB (2K × 16) | 8 KB (4K × 16) | 4 KB (2K × 16) | 4 KB (2K × 16) | 4 KB (2K × 16) | 16 KB (8K × 16) |
| RAM | 232 B | 454 B | 232 B | 232 B | 232 B | 454 B |
| Number of I/O | 33 | 33 | 33 | 33 | 33 | 33 |
| Maximum Clock Frequency | 33 MHz (oscillator) | 33 MHz (oscillator) | 33 MHz (oscillator) | 33 MHz (oscillator) | 33 MHz (oscillator) | 33 MHz (oscillator) |
| Instruction Cycle Time | 121 ns | 121 ns | 121 ns | 121 ns | 121 ns | 121 ns |
| Operating Temperature | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (Industrial) | -40 °C to +125 °C (Extended) | 0 °C to +70 °C (Commercial) | -40 °C to +85 °C (Industrial) |
| Supply Voltage | 4.5 V to 6 V | 4.5 V to 6 V | 4.5 V to 6 V | 4.5 V to 6 V | 4.5 V to 6 V | 4.5 V to 6 V |
Key Differentiators
- Largest OTP program memory in 44-PLCC PIC17C4X family (vs PIC17C43-16I/L)
- Industrial temperature grade with PLCC-44 footprint (vs PIC17C42A-16/L)
- Stable 16 MHz instruction cycle across PIC17C4X PLCC family (vs PIC18F4220)
Design Notes
The PIC17C42A-16I/L operates from 4.5 V to 6 V; use a regulated 5 V rail from an LDO (e.g., MCP1700 or MCP1754) rather than a raw rectified supply. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of each VDD pin and a bulk 10 µF tantalum or aluminum electrolytic on the board supply entry. For OTP programming in production, ensure VDD rises monotonically during reset to avoid inadvertent code-execution before programming completes.
Route the 33 MHz oscillator traces (OSC1, OSCC2) short and shielded by a guard ground to limit radiated emissions. Place the crystal/capacitor combination within 5 mm of the OSC1/OSC2 pins. For the 44-pin PLCC socket used in production, prefer a machine-pin socket with retention pin holes, rather than a leaf-solder type, to survive OTP programming insertion cycles and field-service rework. Add a 100 nF decoupling cap adjacent to every VDD pin (the part has multiple VSS/VDD pairs on the PLCC-44).
OTP (one-time-programmable) memory cannot be erased; verify firmware with a windowed PIC17C42AT sample or a flash-equivalent before committing to OTP production units. Note that the PLCC-44 package has multiple VSS pins that all must be connected - floating any VSS pin causes latch-up or undefined behavior. The MCLR pin is active-low; if left floating it may spontaneously reset due to its high impedance. Tie MCLR to VDD through a 10 kΩ pull-up and a 100 nF decoupling cap to ground for noise immunity.
Compliance Information
RoHS, lead-free, halogen-free, and conflict-minerals data were not consistently published in the verified distributor sources and are marked unknown. PIC17C4X family parts predate universal RoHS transition; PLCC termination finish typically contains lead. The part is not AEC-Q100 qualified and is not recommended for new automotive safety applications. Confirm compliance via Microchip's certificate of conformance for the specific lot/date code before placing regulated orders.
