PIC17C42AT-16E/PQ - 4KB OTP 8-Bit MCU, 16MHz, 44-MQFP
MPN: PIC17C42AT-16E/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.95 | $8.95 |
| 10 | $8.1 | $81.00 |
| 100 | $7.05 | $705.00 |
| 500 | $6.2 | $3,100.00 |
| 1,000 | $5.4 | $5,400.00 |
PIC17C42AT-16E/PQ Overview
What is an OTP microcontroller? An OTP microcontroller (One-Time Programmable) is a device that stores program code in a non-rewritable EPROM/EPROM-based memory cell, programmed once at production or in-circuit. The PIC17C42A belongs to the PIC17C4X high-performance 8-bit CMOS family, sitting between classical PIC16 and PIC18 architectures in the Microchip taxonomy. The Harvard architecture separates 16-bit program fetches from 8-bit data accesses via independent buses, enabling single-cycle instruction execution typical of the PIC17C series.
Key features include a 16 MHz maximum clock (4 MHz input with 4x PLL option per family datasheet), 33 I/O pins, two 8-bit timers plus one 16-bit timer/counter, a USART with 9-bit address mode, 8-channel 8-bit A/D (family feature) and a wide operating voltage range typical of CMOS EPROM MCUs. The PIC17C42AT-16E/PQ 'E' suffix denotes the Extended industrial temperature grade (-40C to +125C), and the 'T' denotes Tape & Reel packaging.
Typical applications include industrial control subsystems, motor control interfaces, sensor signal conditioning front-ends, smart instrumentation, automotive body electronics (non-safety) and embedded communication bridges. The 33 I/O count and USART support point to legacy designs where the PIC17C42A is used as a peripheral controller or a glue-logic replacement for discrete CMOS.
Designers should treat OTP parts as write-once: confirm firmware with emulation (PIC17C43 with windowed EPROM) before committing to PIC17C42A production units. Provide a clean +5 V analog/digital supply rail with decoupling at VDD/VSS pins and respect the 33 I/O sink/source limits.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC17C42AT-16E/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-16E/PQ (same form factor and footprint) — differing in Core Architecture, Package, Mounting Type, Program Memory Type, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC17C43A-16E/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC17C42A-16E/PQ
✅ Drop-In✓ In Stock
$6.08 / 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 →PIC17C42A-16I/PQ
✅ Drop-In✓ In Stock
$8.95 / Unit
View Datasheet →PIC17C42AT-16E/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Family | PIC17C4X (PIC17C42A) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes |
| Maximum Clock Frequency | 16 MHz |
| Instruction Throughput | 16 MIPS |
| Number of I/O Pins | 33 |
| Package | 44-MQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Oscillator Type | External |
| Temperature Grade | Extended (-40C to +125C) |
| Packaging | Tape & Reel (TR) |
| RoHS Status | unknown |
PIC17C42AT-16E/PQ Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 4 | RA3/AN3 — PORTA bit 3 / analog input 3 |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 6 | RA5/SS — PORTA bit 5 / SPI slave select |
| Pin 7 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 8 | OSC2/CLKOUT — Oscillator output / clock out |
| Pin 9 | MCLR — Master clear reset (active low) |
| Pin 10 | VSS — Ground |
| Pin 11 | VDD — Positive supply |
| Pin 12 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 13 | RB1 — PORTB bit 1 |
| Pin 14 | RB2 — PORTB bit 2 |
| Pin 15 | RB3 — PORTB bit 3 |
| Pin 16 | RB4 — PORTB bit 4 |
| Pin 17 | RB5 — PORTB bit 5 |
| Pin 18 | RB6 — PORTB bit 6 |
| Pin 19 | RB7 — PORTB bit 7 |
| Pin 20 | VSS — Ground |
| Pin 21 | RC0/T1CKI — PORTC bit 0 / Timer1 clock input |
| Pin 22 | RC1/CCP1 — PORTC bit 1 / capture compare PWM 1 |
| Pin 23 | RC2/CCP2 — PORTC bit 2 / capture compare PWM 2 |
| Pin 24 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 25 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 26 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 27 | RC6/TX/CK — PORTC bit 6 / USART TX / clock |
| Pin 28 | RC7/RX/DT — PORTC bit 7 / USART RX / data |
| Pin 29 | RD0 — PORTD bit 0 |
| Pin 30 | RD1 — PORTD bit 1 |
| Pin 31 | RD2 — PORTD bit 2 |
| Pin 32 | RD3 — PORTD bit 3 |
| Pin 33 | RD4 — PORTD bit 4 |
| Pin 34 | RD5 — PORTD bit 5 |
| Pin 35 | RD6 — PORTD bit 6 |
| Pin 36 | RD7 — PORTD bit 7 |
| Pin 37 | RE0 — PORTE bit 0 |
| Pin 38 | RE1 — PORTE bit 1 |
| Pin 39 | RE2 — PORTE bit 2 |
| Pin 40 | VDD — Positive supply |
| Pin 41 | VSS — Ground |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | TEST — Test mode enable (factory only) |
Typical Applications
PIC17C42AT-16E/PQ is suitable for 6 applications: Industrial Control Subsystems, Motor Control Interfaces, Sensor Signal Conditioning Front-Ends, Smart Instrumentation, Automotive Body Electronics (Non-Safety), Embedded Communication Bridges.
Industrial Control Subsystems
The PIC17C42AT-16E/PQ fits industrial control subsystems where 33 digital I/O pins, 16 MIPS throughput, and an Extended -40C to +125C temperature rating are required. Its Harvard architecture executes most instructions in a single cycle, ideal for deterministic closed-loop tasks such as PID valve control, conveyor sequencing and machine-tool interlocks. The on-chip USART supports RS-485 multi-drop networking up to 375 kbps at 16 MHz, while the 16-bit TIMER2 enables precise PWM generation for motor speed regulation. Use it as a peripheral controller between a host PLC and field sensors, where OTP memory is acceptable for frozen firmware. Pair with external op-amps for analog front-end and a 24LC256 EEPROM for parameter logging in the same 44-MQFP footprint.
Recommended
Motor Control Interfaces
The PIC17C42AT-16E/PQ is well matched to brushed DC and stepper motor control boards. Its three timers (TMR0 8-bit, TMR1 8-bit, TMR2 16-bit with prescaler) provide independent time bases for commutation, current sampling and PWM generation. The 16 MIPS throughput at 16 MHz runs the field-oriented control or trapezoidal commutation algorithm without CPU stall, while the 33 I/O pins drive direction, brake, fault, encoder A/B inputs and enable signals for up to three H-bridges. Extended temperature grade enables under-hood or chassis-mounted placement. The OTP program memory ensures the firmware cannot be tampered with in the field, valuable for OEM-locked motor controllers.
Recommended
Sensor Signal Conditioning Front-Ends
Bridge sensors, thermocouples and RTD arrays need a local microcontroller for cold-junction compensation, linearization and digital filtering. The PIC17C42AT-16E/PQ's 16 MIPS core executes polynomial linearization and digital low-pass filters on 33 digital I/O pins connected to muxed sensor channels. Harvard architecture lets the MCU read A/D samples on one bus while computing corrections on the parallel instruction bus without pipeline stalls. The OTP memory locks the calibration constants, making the module tamper-resistant for metrology applications. Pair with an external 16-bit ADC such as MCP3421 over I2C for sub-microvolt resolution; the MCU handles data buffering and host communication via USART.
Recommended
Smart Instrumentation
Bench-top instruments, data loggers and panel meters benefit from the PIC17C42AT-16E/PQ's combination of 33 I/O, USART and 16 MIPS throughput. The Extended -40C to +125C temperature rating tolerates warm enclosures with limited airflow. Use PORTD for 8-bit LCD data bus and PORTE for control lines, leaving PORTA and PORTB free for keypads and rotary encoders. TIMER2 generates a 1 ms tick for real-time-clock scheduling. OTP program memory ensures locked firmware for metrology certification paths. The 232 x 8 RAM is sufficient for floating-point measurement buffers. Designers also choose the part for its stable long-term supply from Microchip distribution channels, important for industrial instruments with 10+ year production runs.
Recommended
Automotive Body Electronics (Non-Safety)
Non-safety body controllers in vehicles - HVAC blend doors, seat position memory, lighting multiplexers - can use the PIC17C42AT-16E/PQ when AEC-Q100 is not mandatory. The Extended -40C to +125C temperature grade covers cabin and engine-bay-adjacent environments. 33 I/O drive LIN slaves, switch matrices and LED drivers, while the USART implements LIN protocol via a software bit-bang layer or external transceiver. 16 MIPS throughput runs the LIN scheduler and PWM dimming simultaneously. Designers often pick the OTP variant to lock body-calibration data permanently. For safety-critical ECUs (ABS, airbag) choose a Q100-qualified MCU; for body electronics, the PIC17C42A cost-optimizes the BOM.
Recommended
Embedded Communication Bridges
The PIC17C42AT-16E/PQ serves as a protocol-translation bridge between legacy serial buses and modern fieldbuses. Its USART plus software bit-bang I2C and SPI handlers run concurrently thanks to the Harvard architecture and 16 MIPS throughput. 33 I/O pins handle bus arbitration, address decoding and handshake lines for multi-master bridges. Common designs use it as RS-232 to RS-485 converters, RS-232 to I2C gateways, or LIN to UART adapters. The OTP memory guarantees the bridge firmware cannot be overwritten by rogue traffic, important for industrial fieldbus isolation. Extended temperature grade supports outdoor cabinet deployment. Stack the part with a MAX485 RS-485 transceiver and an ADM3251E isolated RS-232 transceiver for a complete bridge module in a 44-MQFP layout.
Recommended
Recommended Products Summary
Engineering reference data for PIC17C42AT-16E/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC17C43A-16E/PQ | PIC17C42A-16E/PQ | PIC17C42A-33I/PQ | PIC17C42A-33I/P | PIC17C42A-16I/PQ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (10x10 mm) | 44-MQFP - same | 44-MQFP - same | 44-MQFP - same | 44-MQFP - same | 44-MQFP - same |
| Program Memory | 4 KB OTP | 4 KB windowed EPROM | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP |
| Max Clock Frequency | 16 MHz | 16 MHz | 16 MHz | 33 MHz | 33 MHz | 16 MHz |
| RAM Size | 232 x 8 | 232 x 8 | 232 x 8 | 232 x 8 | 232 x 8 | 232 x 8 |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 33 |
| Temperature Grade | Extended (-40C to +125C) | Extended (-40C to +125C) | Commercial (0C to +70C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) |
| Memory Type | OTP (one-time) | Windowed EPROM (erasable) | OTP | OTP | OTP | OTP |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Extended temperature grade vs commercial-only siblings (vs PIC17C42A-16E/PQ (same die, commercial 0C to +70C))
- Tape & Reel packaging vs tube (vs PIC17C42A-16E/P (tube version))
- Obsolete status with stable distribution inventory vs active new designs (vs PIC18F4520-I/PT (active flash MCU))
- 16 MHz vs 33 MHz speed option (vs PIC17C42A-33I/PQ (33 MHz drop-in))
Design Notes
Estimated: supply the PIC17C42AT-16E/PQ from a +5 V LDO such as MCP1755 with a 10 uF bulk + 0.1 uF ceramic decoupling placed within 5 mm of VDD pins 11 and 40. The PIC17C4X family draws approximately 15-25 mA active at 16 MHz. Add a bulk capacitor on the LDO output to absorb the inrush during Flash/OTP programming pulses, which can momentarily pull 50 mA on VPP. Keep digital VDD and analog AVSS traces short and avoid sharing ground returns with relay or motor drive stages.
Estimated: the 44-MQFP package has a theta_JA around 50 C/W on a 4-layer 1-oz copper JEDEC test board. At maximum ambient +125C and 20 mA active current (about 100 mW dissipation), the junction rises roughly 5C, leaving ample margin. However, do not place the part directly above a heatsink or transformer; route thermal vias under the exposed die-attach pad if available. The Extended temperature grade is suitable for closed industrial cabinets but should be derated for sealed enclosures with no airflow.
PIC17C42A is OTP - once programmed, firmware bugs cannot be field-patched. Validate code on a PIC17C43A windowed EPROM variant in the same 44-MQFP footprint before committing to the OTP part. Beware the TEST pin (44): leaving it floating may put the device in factory test mode. Tie TEST to VSS through a 10 kohm resistor. MCLR must use a 10 kohm pull-up to VDD with a 0.1 uF decoupling cap; do not let MCLR float or the MCU may intermittently reset under EMI.
Place the 16 MHz crystal within 5 mm of OSC1 (pin 7) and OSC2 (pin 8) with the load capacitors (typically 15-33 pF) routed symmetrically to ground. Keep the crystal traces short and guarded by a ground ring to avoid radiated EMI. The MCLR trace should be short and away from high-current switching nodes. Route PORTD (pins 29-36) and PORTB (pins 12-19) with matched trace lengths if the firmware uses parallel bus protocols to avoid skew. Provide a 4-layer PCB with continuous ground plane under the MCU for best EMI/ESD immunity.
Compliance Information
Compliance fields not specified in the verified snippet; RoHS/REACH/AEC-Q100 status should be confirmed with Microchip for new design-ins. The part is OTP (not field-reprogrammable) and not recommended for safety-critical automotive designs that require AEC-Q100.
