PIC17LC42A-08/PT - 8-bit 8MHz 4KB OTP MCU 44-TQFP | Microchip
MPN: PIC17LC42A-08/PT ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $11.5 | $11.50 |
| 10 | $10.35 | $103.50 |
| 100 | $9.2 | $920.00 |
| 500 | $8.05 | $4,025.00 |
| 1,000 | $6.9 | $6,900.00 |
PIC17LC42A-08/PT Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (ROM/Flash/OTP), data memory (RAM), and configurable peripheral I/O on one silicon die. The PIC architecture pioneered Harvard memory organization with separate code and data buses, enabling simultaneous instruction fetch and data access. The PIC17 family sits above the PIC16 and below the PIC18 in the Microchip 8-bit hierarchy, adding a wider 16-bit instruction word and multiply support for higher code density and arithmetic throughput.
Key features of the PIC17LC42A-08/PT include a 4KB OTP program memory, 232 bytes of general-purpose RAM, 33 I/O pins, an external oscillator interface, brown-out reset, a watchdog timer with on-chip RC oscillator, and a power-saving SLEEP mode. The 8MHz clock speed (suffix -08) corresponds to a 121 ns instruction cycle. On-chip peripherals include a USART, a 16-bit timer/counter, capture/compare/PWM modules, and an 8-bit A/D converter.
Typical applications include industrial control, motor control, automotive subsystems, security and alarm panels, and embedded control requiring deterministic single-cycle execution. The wide 5V supply tolerance and external oscillator support make it well suited to noisy industrial environments. When designing with this MCU, allocate sufficient decoupling (100 nF ceramic on each VDD pair) and follow Microchip's recommended in-circuit serial programming (ICSP) layout for production programming.
Drop-in alternatives for PIC17LC42A-08/PT — 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 PIC17LC42A-08/PT (same form factor and footprint) — differing in Core Architecture, Maximum Clock Frequency, Package, Program Memory Size, RAM Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-08/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17LC42A-08I/PT
✅ Drop-In✓ In Stock
$9.75 / Unit
View Datasheet →PIC17C42AT-25/PT
✅ Drop-In✓ In Stock
$10.5 / Unit
View Datasheet →PIC17C42A-33/PT
✅ Drop-In✓ In Stock
$9.65 / Unit
View Datasheet →PIC17LC42A-08/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC17C |
| Program Memory Size | 4 KB (2K x 16) OTP |
| RAM Size | 232 x 8 bytes (454 bytes) |
| EEPROM Size | None (external only) |
| Maximum Clock Frequency | 8 MHz (-08 speed grade) |
| Maximum CPU Throughput | 8 MIPS |
| Instruction Cycle | 121 ns (single cycle, except branches) |
| Instruction Set Size | 58 single-word instructions |
| Number of I/O Pins | 33 |
| Supply Voltage (Vdd) | 3.0 V to 5.5 V |
| Oscillator Type | External |
| Package | 44-TQFP (10x10 mm) |
| Operating Temperature | 0C to +70C (commercial) |
| On-chip Peripherals | USART, 16-bit Timer, CCP, 8-bit ADC |
| Programming Method | ICSP (In-Circuit Serial Programming) |
PIC17LC42A-08/PT Pin Configuration
| Pin 1 | OSC1/CLKIN — Oscillator crystal input or external clock input |
| Pin 2 | OSC2/CLKOUT — Oscillator crystal output or clock output |
| Pin 3 | RA0/AN0 — Port A bit 0 / analog input 0 |
| Pin 4 | RA1/AN1 — Port A bit 1 / analog input 1 |
| Pin 5 | RA2/AN2 — Port A bit 2 / analog input 2 |
| Pin 6 | RA3/AN3 — Port A bit 3 / analog input 3 |
| Pin 7 | RA4/T0CKI — Port A bit 4 / Timer 0 clock input |
| Pin 8 | RA5/SS — Port A bit 5 / SPI slave select |
| Pin 9 | MCLR/VPP — Master clear reset (active low) / programming voltage input |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply (3.0V to 5.5V) |
| Pin 12 | RB0/INT — Port B bit 0 / external interrupt |
| Pin 13 | RB1 — Port B bit 1 |
| Pin 14 | RB2 — Port B bit 2 |
| Pin 15 | RB3 — Port B bit 3 |
| Pin 16 | RB4 — Port B bit 4 |
| Pin 17 | RB5 — Port B bit 5 |
| Pin 18 | RB6 — Port B bit 6 |
| Pin 19 | RB7 — Port B bit 7 |
| Pin 20 | RC0 — Port C bit 0 |
| Pin 21 | RC1 — Port C bit 1 |
| Pin 22 | RC2 — Port C bit 2 |
| Pin 23 | RC3 — Port C bit 3 |
| Pin 24 | RC4 — Port C bit 4 |
| Pin 25 | RC5 — Port C bit 5 |
| Pin 26 | RC6/TX/CK — Port C bit 6 / USART TX / clock |
| Pin 27 | RC7/RX/DT — Port C bit 7 / USART RX / data |
| Pin 28 | RD0 — Port D bit 0 |
| Pin 29 | RD1 — Port D bit 1 |
| Pin 30 | RD2 — Port D bit 2 |
| Pin 31 | RD3 — Port D bit 3 |
| Pin 32 | RD4 — Port D bit 4 |
| Pin 33 | RD5 — Port D bit 5 |
| Pin 34 | RD6 — Port D bit 6 |
| Pin 35 | RD7 — Port D bit 7 |
| Pin 36 | RE0/AN5 — Port E bit 0 / analog input 5 |
| Pin 37 | RE1/AN6 — Port E bit 1 / analog input 6 |
| Pin 38 | RE2/AN7 — Port E bit 2 / analog input 7 |
| Pin 39 | VDD — Positive supply (3.0V to 5.5V) |
| Pin 40 | VSS — Ground reference |
| 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
PIC17LC42A-08/PT is suitable for 6 applications: Industrial Process Control, Motor Control and Drives, Security and Alarm Panels, Automotive Body Electronics, Embedded Data Acquisition Systems, White Goods and Appliance Control.
Industrial Process Control
The PIC17LC42A-08/PT fits industrial process control because its single-cycle 121 ns instruction execution and 8 MIPS throughput deliver deterministic response for closed-loop PID loops running at sub-millisecond intervals. The 33 digital I/O lines accept multiple 4-20 mA sensor inputs via external signal conditioning and drive triac/SSR outputs, while the on-chip USART provides RS-232/RS-485 connectivity to SCADA systems. The 3.0V to 5.5V supply tolerance accommodates 24V industrial bus rails after regulation, and brown-out reset plus watchdog timer protect against the brown-out and EMI-induced lockup events common on factory floors.
Recommended
Motor Control and Drives
The PIC17LC42A-08/PT is well suited to low-cost stepper and brushed DC motor control because its 16-bit timer and Capture/Compare/PWM modules generate precise switching waveforms up to 8 MIPS, easily handling 10 kHz PWM frequencies with substantial CPU overhead for commutation logic. The 33 I/O pins drive H-bridge gate signals, end-of-travel limits, and quadrature encoder inputs simultaneously. Single-cycle execution ensures low PWM jitter, which is critical for smooth torque and reduced audible noise in variable-speed drives used in appliances, pumps, and small CNC machines.
Recommended
Security and Alarm Panels
The PIC17LC42A-08/PT powers commercial security and alarm panels by reading 33 zones of PIR sensors, magnetic switches, and smoke detectors while driving siren, keypad, and dialer outputs. The on-chip USART interfaces to a PSTN dialer modem or cellular module for off-premises communication, and the watchdog timer plus brown-out reset ensure the panel recovers from power glitches. The PIC's OTP memory prevents firmware reverse-engineering and reprogramming attempts, an important security property for alarm systems. SLEEP mode reduces quiescent current during armed standby to extend backup-battery runtime.
Recommended
Automotive Body Electronics
For non-safety automotive body modules such as seat controllers, mirror adjusters, and HVAC blend-door actuators, the PIC17LC42A-08/PT provides adequate compute and I/O density. The on-chip 8-bit ADC reads potentiometer positions for blend doors and mirror positioning, the USART interfaces to the body control module via LIN bus (with external transceiver), and the PWM outputs drive small DC motors. Note that the commercial temperature grade limits deployment to cabin modules; underhood applications require the PIC17LC42A-08I/PT industrial grade. Wide 5V tolerance tolerates load-dump and cranking transients when paired with a TVS and filter.
Recommended
Embedded Data Acquisition Systems
The PIC17LC42A-08/PT serves low-cost 8-channel data-acquisition front ends, where its 8-bit on-chip ADC samples at rates up to approximately 50 ksps and stores readings in the 232-byte RAM buffer for batching over the USART to a host PC. The 33 I/O expand the addressable channels via external analog multiplexers such as the 4051. Brown-out reset protects in-progress acquisitions from corrupted low-voltage writes. The deterministic 121 ns instruction cycle lets designers calculate exact sampling jitter, a property valuable for instrumentation and laboratory equipment.
Recommended
White Goods and Appliance Control
The PIC17LC42A-08/PT targets cost-sensitive white-goods applications like washing machines, dishwashers, and microwave ovens where its 33 I/O drive seven-segment displays, keypads, solenoid valves, and triac-switched heater or motor loads. The on-chip PWM modules control universal motor speed and heater phase-angle firing. The PIC's OTP memory and wide supply tolerance handle the noisy switch-mode power environment found in appliances, while the SLEEP mode reduces standby power to meet energy-efficiency regulations such as ENERGY STAR. The industrial temperature -I variant is preferred for oven and refrigeration modules.
Recommended
Recommended Products Summary
Engineering reference data for PIC17LC42A-08/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-08/PT | PIC17LC42A-08I/PT | PIC17C42AT-25/PT | PIC17C42A-33/PT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) | 44-TQFP (10x10 mm) |
| Maximum Clock | 8 MHz | 8 MHz | 8 MHz | 25 MHz | 33 MHz |
| Program Memory | 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 |
| I/O Pins | 33 | 33 | 33 | 33 | 33 |
| Supply Voltage | 3.0 V to 5.5 V | 4.5 V to 5.5 V | 3.0 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Operating Temperature | 0C to +70C (commercial) | 0C to +70C | -40C to +85C (industrial) | 0C to +70C | 0C to +70C |
Key Differentiators
- Wide 3.0V to 5.5V supply supports 3.3V low-voltage designs (vs PIC17C42A-08/PT)
- Industrial temperature range option in same package (vs PIC17LC42A-08/PT (commercial))
- Higher-speed PIC17C family options available in same footprint (vs PIC17C42A-25/PT (Site MPN list))
Design Notes
Place a 100 nF ceramic decoupling capacitor on each VDD pin (pins 11 and 39) within 5 mm of the package, with the trace to VDD kept short and wide. Add a 10 uF bulk tantalum or aluminum electrolytic at the regulator output. The PIC17LC42A-08/PT draws approximately 30 mA active at 8MHz/5V and under 10 uA in SLEEP. For 3.3V-only designs use a low-dropout regulator such as MCP1700-3302E; for 5V designs an LM7805 or equivalent is acceptable.
MCLR (pin 9) requires a 10 kohm pull-up to VDD; a 100 nF capacitor to ground on MCLR delays reset release and prevents spurious resets during power-ramp. For ICSP programming, isolate the MCLR pull-up and ensure the PGD/PGC lines (typically RC6/RC7 or RB6/RB7) have no series resistance above 470 ohm and are not multiplexed to loads that exceed 20 pF. Reserve a 5-pin header footprint for ICSP even on production boards - field firmware updates may be required.
Do not exceed 8 MHz clock input for the -08 speed grade; faster clocks produce out-of-spec instruction timing and may cause EEPROM or program-memory corruption. Ensure the watchdog timer is enabled in long-running applications to recover from code lockup - the internal 16 ms nominal WDT period can be extended by prescaler. The PIC17LC42A does not contain a hardware multiply instruction - implement 16x16 multiplication in software using shifts and adds, or use the table-read and add-subtract combination for moderate throughput.
Compliance Information
RoHS/REACH compliance status not explicitly stated in verified web data; PIC17 family parts are predominantly pre-2010 designs and may not be RoHS compliant by default. Mark as unknown per data-availability rules.