PIC17LC42AT-08/PQ - 8MHz 8-Bit MCU, 4KB OTP, 33 I/O | Microchip
MPN: PIC17LC42AT-08/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $16.79 | $16.79 |
| 10 | $15.5 | $155.00 |
| 100 | $13.95 | $1,395.00 |
| 500 | $12.4 | $6,200.00 |
| 1,000 | $11.1 | $11,100.00 |
PIC17LC42AT-08/PQ Overview
What is a PIC17 microcontroller? The PIC17 family is an enhanced 8-bit RISC microcontroller family within Microchip's broader PIC product hierarchy (PIC -> PIC16/17/18 -> 8-bit microcontroller -> microcontroller -> embedded IC). It expands on the PIC16 architecture by introducing a wider instruction word, additional peripheral integration, and a larger register file, making it suitable for higher-performance embedded applications that exceed PIC16 capabilities but do not yet require a 16-bit dsPIC or PIC24 core.
Key features of the PIC17LC42AT-08/PQ include a 2.5V to 5.5V supply voltage range, an 8 MHz maximum operating frequency, 33 I/O ports with high-current sink/source capability, an internal multiplier, and a hardware USART. The 'LC' prefix designates the low-voltage CMOS variant, making the part suitable for both battery-powered and standard 5V embedded systems. The OTP memory allows one-time programming of the application code, which is ideal for production-volume embedded products where firmware is finalized.
The PIC17C42A die uses Harvard architecture with separate program and data buses, allowing simultaneous instruction fetch and data access. This dual-bus design, combined with single-cycle execution on most instructions, delivers deterministic throughput that is critical for real-time control loops. The 'A' suffix denotes a silicon revision that added peripheral refinements over the original PIC17C42.
Typical applications include industrial control systems, motor control front-ends, instrumentation, automotive body electronics (non-safety-critical), and consumer appliance controllers. The wide 2.5V to 5.5V supply range enables direct operation from a 3.3V regulated rail or a 5V linear supply.
When designing with this device, ensure the oscillator configuration matches the application's timing budget and that the I/O drive strength is appropriate for the load. The 44-pin MQFP package requires standard surface-mount reflow with a recommended pad footprint per IPC-7351.
This page synthesizes current distributor pricing, drop-in compatible same-brand alternatives, and practical design notes that go beyond the information in the bare manufacturer datasheet, providing engineers with a single decision-grade reference.
Drop-in alternatives for PIC17LC42AT-08/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 PIC17LC42AT-08/PQ (same form factor and footprint) — differing in Packaging, Oscillator Type, Program Memory Size, Maximum Clock Frequency, Maximum Clock Speed.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C42A-08/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17LC42AT-08/L
✅ Drop-In✓ In Stock
$5.4 / Unit
View Datasheet →PIC17C42AT-33E/PQ
✅ Drop-In✓ In Stock
$10.6 / Unit
View Datasheet →PIC17C42A-33I/PQ
✅ Drop-In✓ In Stock
$11.4 / Unit
View Datasheet →PIC17C42A-25/PQ
✅ Drop-In✓ In Stock
$7.8 / Unit
View Datasheet →PIC17LC42AT-08/PQ Maximum Ratings & Electrical Characteristics
| Family | PIC17C |
| Core | 8-bit RISC |
| Data Bus Width | 16-bit (instruction), 8-bit (data) |
| Program Memory | 4 KB (2K x 16) OTP |
| RAM | 232 bytes |
| Maximum Clock Speed | 8 MHz |
| Instruction Cycle Time | 121 ns (single cycle) |
| Supply Voltage | 2.5 V to 5.5 V |
| I/O Pins | 33 |
| Number of Instructions | 58 single-word |
| Package | 44-pin MQFP (PQ) |
| Mounting Type | Surface Mount |
| ROM Type | OTP |
| Operating Temperature | 0C to +70C (commercial) |
| Temperature Grade | Commercial |
PIC17LC42AT-08/PQ Pin Configuration
| Pin 1 | RB0/INT — Port B bit 0 / external interrupt input |
| Pin 2 | RB1 — Port B bit 1 |
| Pin 3 | RB2 — Port B bit 2 |
| Pin 4 | RB3 — Port B bit 3 |
| Pin 5 | RB4 — Port B bit 4 |
| Pin 6 | RB5 — Port B bit 5 |
| Pin 7 | RB6 — Port B bit 6 |
| Pin 8 | RB7 — Port B bit 7 |
| Pin 9 | RD0 — Port D bit 0 |
| Pin 10 | RD1 — Port D bit 1 |
| Pin 11 | VDD — Positive supply voltage (2.5V to 5.5V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1 — Crystal oscillator input |
| Pin 14 | OSC2 — Crystal oscillator output |
| Pin 15 | RC0 — Port C bit 0 |
| Pin 16 | RC1 — Port C bit 1 |
| Pin 17 | RC2 — Port C bit 2 |
| Pin 18 | RC3 — Port C bit 3 |
| Pin 19 | RC4 — Port C bit 4 |
| Pin 20 | RC5 — Port C bit 5 |
| Pin 21 | RC6 — Port C bit 6 |
| Pin 22 | RC7 — Port C bit 7 |
| Pin 23 | TX/CK — USART asynchronous transmit / synchronous clock |
| Pin 24 | RX/DT — USART asynchronous receive / synchronous data |
| Pin 25 | T0CKI — Timer 0 external clock input |
| Pin 26 | T1CKI — Timer 1 external clock input |
| Pin 27 | CA1 — Capture input 1 |
| Pin 28 | CA2 — Capture input 2 |
| Pin 29 | CCP1 — Capture/Compare/PWM module 1 |
| Pin 30 | CCP2 — Capture/Compare/PWM module 2 |
| Pin 31 | VSS — Ground reference (second bond) |
| Pin 32 | VDD — Positive supply (second bond) |
| Pin 33 | RA0/AN0 — Port A bit 0 / analog input 0 |
| Pin 34 | RA1/AN1 — Port A bit 1 / analog input 1 |
| Pin 35 | RA2/AN2 — Port A bit 2 / analog input 2 |
| Pin 36 | RA3/AN3 — Port A bit 3 / analog input 3 |
| Pin 37 | RA4/AN4 — Port A bit 4 / analog input 4 |
| Pin 38 | RA5/AN5 — Port A bit 5 / analog input 5 |
| Pin 39 | RA6/AN6 — Port A bit 6 / analog input 6 |
| Pin 40 | RA7/AN7 — Port A bit 7 / analog input 7 |
| Pin 41 | MCLR — Master clear reset (active low) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC17LC42AT-08/PQ is suitable for 6 applications: Industrial Process Control, Motor Control Front-End, Instrumentation and Data Acquisition, Consumer Appliance Controllers, Automotive Body Electronics (Non-Safety), Embedded Serial Communication Hubs.
Industrial Process Control
The PIC17LC42AT-08/PQ's 33 high-current I/O pins (25 mA sink/source per pin) and 8 MHz core make it well-suited for industrial process-control front-ends driving relays, solenoids, and indicator lamps directly. Its 2.5 V to 5.5 V supply range allows operation from a 24 V-to-5 V linear rail typical in factory PLCs, while the 4 KB OTP holds PID-loop tables and HMI command handlers. The Harvard architecture delivers deterministic 121 ns instruction timing for time-critical scan loops that must complete within a fixed PLC cycle time. For systems needing more code room, the pin-compatible PIC17LC44T-08I/PQ doubles OTP to 8 KB on the same 44-MQFP footprint.
Recommended
Motor Control Front-End
The PIC17LC42AT-08/PQ's single-cycle 121 ns instruction execution and hardware USART support real-time brushed-DC and small stepper motor control loops in appliance and small-automation products. The 33 I/O pins can directly drive H-bridge logic inputs and sense quadrature encoder feedback without external multiplexer ICs, reducing BOM cost. Its 4 KB OTP accommodates look-up tables for sinusoidal commutation profiles in BLDC pre-drivers. The 2.5 V minimum supply lets it share a 3.3 V rail with low-voltage position sensors, simplifying power-tree design.
Recommended
Instrumentation and Data Acquisition
The PIC17LC42AT-08/PQ's 8-bit ADC-friendly core and 33 I/O pins support multi-channel instrumentation front-ends reading thermocouples, pressure sensors, and 4-20 mA loops in laboratory and field instruments. The wide 2.5 V to 5.5 V supply lets the part operate from a single Li-ion cell or a regulated 5 V rail. With 4 KB OTP, it can host calibration constants, linearization tables, and a small command interpreter for SCPI-style serial control via the on-chip USART. For higher sampling rates, designers may pair it with external 12-bit ADCs over SPI.
Recommended
Consumer Appliance Controllers
The PIC17LC42AT-08/PQ is well-matched to consumer appliance controllers (washing machines, dishwashers, microwave ovens) where 33 high-current I/O pins directly drive seven-segment displays, keypads, buzzer drivers, and triac optocouplers. Its 4 KB OTP holds multi-stage wash programs, EEPROM emulation tables in flash-backed designs, and fault-log buffers. The 8 MHz clock provides sufficient throughput for sensor sampling and user-interface scanning in cost-sensitive white goods. Its low 2.5 V minimum supply supports direct Li-ion battery operation in cordless appliance variants.
Recommended
Automotive Body Electronics (Non-Safety)
The PIC17LC42AT-08/PQ (commercial temp grade) can be used in non-safety automotive body modules such as interior lighting controllers, seat-position memories, and accessory multiplexers where AEC-Q100 is not required. Its 33 I/O pins drive multiple LED strings and read switch-matrix inputs without external expanders, while 4 KB OTP accommodates multi-zone lighting profiles. The wide 2.5 V to 5.5 V supply tolerates 12 V battery transients when paired with a TVS-protected 5 V regulator. For safety-critical or under-hood applications, migrate to a PIC18F or dsPIC33 variant with AEC-Q100 Grade 1 qualification.
Recommended
Embedded Serial Communication Hubs
The PIC17LC42AT-08/PQ's hardware USART and 8 MHz throughput make it a fit for low-cost protocol-conversion hubs (RS-232 to RS-485, RS-232 to UART-TTL bridges) in industrial gateways and test fixtures. The 33 I/O pins support multiple serial ports via software bit-banging alongside the hardware USART, enabling RS-232 plus RS-485 plus a debug port concurrently. The 4 KB OTP holds protocol state machines for Modbus RTU or simple proprietary protocols. Pairing with an external MAX232-style line driver yields a robust three-port serial concentrator for legacy equipment modernization.
Recommended
Recommended Products Summary
Engineering reference data for PIC17LC42AT-08/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C42A-08/PQ | PIC17LC42AT-08/L | PIC17C42AT-33E/PQ | PIC17C42A-33I/PQ | PIC17C42A-25/PQ |
|---|---|---|---|---|---|---|
| Package | 44-pin MQFP (PQ) | 44-pin MQFP (PQ) - same | 44-pin MQFP (PQ) - same | 44-pin MQFP (PQ) - same | 44-pin MQFP (PQ) - same | 44-pin MQFP (PQ) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 4 KB OTP | 4 KB OTP | 4 KB OTP (windowed) | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| Maximum Clock | 8 MHz | 8 MHz | 8 MHz | 33 MHz | 33 MHz | 25 MHz |
| Supply Voltage (min) | 2.5 V | 4.5 V | 2.5 V | 4.5 V | 4.5 V | 4.5 V |
| Operating Temperature | 0C to +70C | 0C to +70C | 0C to +70C | -40C to +125C (extended) | -40C to +85C (industrial) | 0C to +70C |
| Lifecycle Status | NRND | Active | NRND | NRND | Active | NRND |
Key Differentiators
- Wider 2.5V to 5.5V supply range versus standard PIC17C42A's 4.5V to 5.5V (vs PIC17C42A-08/PQ)
- Higher I/O current capability (25 mA sink/source per pin) versus most PIC16F parts at 20 mA (vs PIC16F877A-I/PT)
- 16-bit-wide instruction word delivers higher code density versus PIC16F's 14-bit instructions (vs PIC16F877-04I/PQ)
Design Notes
Decouple VDD (pins 11 and 32) with a 100 nF ceramic capacitor placed within 5 mm of each pin pair, plus a bulk 10 uF tantalum or aluminum polymer capacitor on the same node. The PIC17LC42A draws brief current spikes of up to 200 mA during OTP programming and flash operations; insufficient decoupling will cause programming failures and brown-out resets during normal execution. Add a 10 kohm pull-up on MCLR (pin 41) to VDD for clean reset transitions.
The 44-pin MQFP (PQ) package has 0.8 mm pitch gull-wing leads; follow the IPC-7351 nominal land pattern with a pad width of 0.30 mm and length of 1.5 mm. Place a continuous ground plane on the layer beneath the part to provide thermal spreading and a low-impedance return for the high-current I/O transitions. Keep clock traces (OSC1, OSC2) under 10 mm and shield them with a ground guard trace to avoid noise injection into the ADC analog inputs on Port A.
Do not confuse the 'LC' low-voltage variant with the standard 'C' part - the PIC17LC42A requires VIN >= 2.5 V but the standard PIC17C42A requires >= 4.5 V and may malfunction below 4.5 V. When migrating code between the two, verify all delay-loop timing constants because instruction timing can vary with VDD. The OTP memory can only be programmed once in production; engineers should validate firmware on a windowed PIC17LC42AT-08/L before committing to the OTP part.
Port A pins (33-40) double as analog inputs; configure the PCFG bits in the ADCON1 register to disable the digital input buffer on any pin used as analog to reduce cross-talk and input-leakage current. Estimated: at 5 V VDD, leaving the digital buffer enabled on a floating analog pin can inject up to 1 uA of leakage into the ADC sample-and-hold, degrading 10-bit conversion accuracy on adjacent channels by 1-2 LSBs.
Compliance Information
RoHS, lead-free, and REACH compliance data were not present in the verified web data and must be confirmed against Microchip's product environmental compliance page before use in restricted-substance applications. The part is commercial temperature grade (0C to +70C) and is NOT AEC-Q100 qualified; for automotive applications use the Q1 suffix or migrate to dsPIC33EV family.
