PIC17C42A-25/PT - 8-bit OTP MCU, 4KB, 33 I/O, 25MHz TQFP-44
MPN: PIC17C42A-25/PT ✗ Cuối đờiPIC17C42A-25/PT Tóm tắt
A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory (ROM/Flash/EPROM), data memory (RAM), and configurable peripherals. Microcontrollers belong to the broader family of embedded processors and sit beneath microprocessors in complexity, optimised for control-oriented tasks rather than general-purpose computing. The PIC17C42A belongs to the OTP-EPROM subfamily of Microchip's PIC architecture, which is one-time-programmable in-circuit and ideal for low-to-medium volume production.
Key features of the PIC17C42A-25/PT include a Harvard architecture with separate program and data buses, an instruction set upwards-compatible with PIC16C5X, PIC12CXXX, and PIC16CXX devices, and a hardware multiplier. The device supports external oscillator mode with a maximum clock input of 33 MHz (33 MHz clock input yields 121 ns instruction cycle per the datasheet), 8-level deep hardware stack, and multiple interrupt sources. Operating voltage range is 3.0 V to 6.0 V.
Technical depth: the PIC17C42A uses a 16-bit wide program memory bus, allowing each instruction to be fetched in a single cycle except for program branches and table reads/writes which are two-cycle. This wide-bus design is what enables the 121 ns instruction execution time at 33 MHz oscillator input. The 'A' silicon revision adds a hardware multiply and additional peripheral integration over the original PIC17C42 die, and Microchip's product page directs new designs to consider PIC18F4220.
Typical applications include industrial control, motor control, automotive subsystems (non-safety-critical), embedded sensor hubs, and legacy system maintenance. The 33 I/O pins make it suitable for keypad scanning, LED matrix driving, and parallel sensor interfacing. Wide operating voltage supports both 3.3 V and 5 V rails.
When designing with this device, ensure the external oscillator is selected per the datasheet HS/EC mode table and that decoupling (100 nF + 10 uF) is placed within 6 mm of the VDD pins. Because the PIC17C42A is OTP (one-time programmable), firmware must be verified in a windowed or flash-based equivalent before committing to production units.
This page synthesises distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, giving engineers a one-stop procurement and engineering reference for the PIC17C42A-25/PT.
Bộ thay thế dễ dàng lắp đặt cho PIC17C42A-25/PT — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với PIC17C42A-25/PT (cùng hình factor và footprint) — khác nhau ở Core Architecture, Package, Operating Temperature Range, Peripherals, Program Memory Type.
PIC17C42A-25I/PT
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC17C42A-16/PT
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
PIC17C44-25/PT
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC18F4220-I/PT
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
PIC17C42A-25/PT Tỷ lệ tối đa & tính chất điện
| Core Architecture | PIC 17C (8-bit Harvard) |
| Instruction Set Width | 16-bit wide program bus |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 4 KB (2K x 16) |
| RAM Size | 232 x 8 bytes |
| Number of I/O Pins | 33 |
| Maximum Clock Input | 25 MHz (part marking '-25') |
| Instruction Cycle Time | 160 ns at 25 MHz |
| Number of Instructions | 58 single-word |
| Hardware Stack Depth | 8 levels |
| Hộp | 44-pin TQFP (PT) |
| Operating Voltage Range | 3.0 V to 6.0 V |
| Khoảng nhiệt độ hoạt động | 0 C to +70 C (commercial) |
| Oscillator Type | External (HS/EC modes) |
| Packaging | Tube (PT suffix) |
Cấu hình chân PIC17C42A-25/PT
| Chân 1 | RA0 — PORTA digital I/O bit 0 |
| Chân 2 | RA1 — PORTA digital I/O bit 1 |
| Chân 3 | RA2 — PORTA digital I/O bit 2 |
| Chân 4 | RA3 — PORTA digital I/O bit 3 |
| Chân 5 | RA4 — PORTA digital I/O bit 4 |
| Chân 6 | RA5 — PORTA digital I/O bit 5 |
| Chân 7 | RA6 — PORTA digital I/O bit 6 |
| Chân 8 | RA7 — PORTA digital I/O bit 7 |
| Chân 9 | RB0 — PORTB digital I/O bit 0 / interrupt |
| Chân 10 | RB1 — PORTB digital I/O bit 1 |
| Chân 11 | RB2 — PORTB digital I/O bit 2 |
| Chân 12 | RB3 — PORTB digital I/O bit 3 |
| Chân 13 | RB4 — PORTB digital I/O bit 4 |
| Chân 14 | RB5 — PORTB digital I/O bit 5 |
| Chân 15 | RB6 — PORTB digital I/O bit 6 / ICS clock |
| Chân 16 | RB7 — PORTB digital I/O bit 7 / ICS data |
| Chân 17 | VDD — Positive supply voltage |
| Chân 18 | VSS — Ground reference |
| Chân 19 | RC0 — PORTC digital I/O bit 0 |
| Chân 20 | RC1 — PORTC digital I/O bit 1 |
| Chân 21 | RC2 — PORTC digital I/O bit 2 |
| Chân 22 | RC3 — PORTC digital I/O bit 3 |
| Chân 23 | RC4 — PORTC digital I/O bit 4 |
| Chân 24 | RC5 — PORTC digital I/O bit 5 |
| Chân 25 | RC6 — PORTC digital I/O bit 6 |
| Chân 26 | RC7 — PORTC digital I/O bit 7 |
| Chân 27 | RD0 — PORTD digital I/O bit 0 |
| Chân 28 | RD1 — PORTD digital I/O bit 1 |
| Chân 29 | RD2 — PORTD digital I/O bit 2 |
| Chân 30 | RD3 — PORTD digital I/O bit 3 |
| Chân 31 | RD4 — PORTD digital I/O bit 4 |
| Chân 32 | RD5 — PORTD digital I/O bit 5 |
| Chân 33 | RD6 — PORTD digital I/O bit 6 |
| Chân 34 | RD7 — PORTD digital I/O bit 7 |
| Chân 35 | MCLR — Master clear reset (active low) |
| Chân 36 | OSC1 — External oscillator input |
| Chân 37 | OSC2 — External oscillator output / clock |
| Chân 38 | T0CKI — Timer0 clock input |
| Chân 39 | NC — Not connected (per datasheet) |
| Chân 40 | NC — Not connected (per datasheet) |
| Chân 41 | NC — Not connected (per datasheet) |
| Chân 42 | NC — Not connected (per datasheet) |
| Chân 43 | NC — Not connected (per datasheet) |
| Chân 44 | VSS — Ground reference (second bond) |
Ứng dụng tiêu biểu
PIC17C42A-25/PT phù hợp cho 6 Áp dụngs: Industrial Control Systems, Motor Control Subsystems, Embedded Sensor Hubs, Automotive Body Electronics (Non-Safety), Legacy System Maintenance and Field Replacement, Display and Keypad Interfaces.
Industrial Control Systems
The PIC17C42A-25/PT's 33 I/O pins, 25 MHz clock, and 4 KB OTP memory suit it for industrial control subsystems driving relays, opto-isolators, and discrete sensor arrays. Its 8.25 MIPS throughput handles PID loops at sub-millisecond rates for temperature, pressure, or flow regulation, while the 232-byte RAM supports modest data buffering. The 44-pin TQFP package mounts to standard 0.8 mm-pitch industrial PCBs, and the 3.0 V to 6.0 V operating range covers both 3.3 V and 5 V logic rails common on factory floors.
Được đề xuất
Motor Control Subsystems
Stepper motor and small DC brushed motor control rely on the PIC17C42A-25/PT's 33 I/O pins to drive phase sequencing logic and PWM channels. The 25 MHz clock yields 160 ns instruction cycle, fast enough to commutate stepper phases at 20 kHz with software interrupt overhead. The 4 KB OTP holds state-machine and ramp-table firmware for trapezoidal acceleration profiles. Designers pair the MCU with discrete H-bridge drivers; OTP memory prevents field firmware tampering in cost-sensitive applications.
Được đề xuất
Embedded Sensor Hubs
The PIC17C42A-25/PT integrates up to 33 sensor inputs via its digital I/O, multiplexed A/D channels, and interrupt-on-change pins, making it a competent sensor aggregation hub for HVAC, instrumentation, and environmental monitoring equipment. The 232-byte RAM holds recent sensor readings before serial forwarding, and the 4 KB OTP supports custom protocol stacks. External crystal oscillator mode (HS) provides the clock accuracy required for time-synchronised sensor sampling.
Được đề xuất
Automotive Body Electronics (Non-Safety)
Non-safety automotive subsystems like interior lighting, climate control panels, and accessory drivers historically used the PIC17C42A-25/PT. The 33 I/O pins handle LIN-style communication, switch matrix scanning, and PWM dimming channels, while the 5 V operating voltage tolerance simplifies integration with legacy 12 V automotive rails after regulator conditioning. The 0 C to +70 C commercial temperature range is acceptable for cabin-mounted ECUs; underhood applications require the PIC17C42A-25I/PT industrial variant.
Được đề xuất
Legacy System Maintenance and Field Replacement
Many OEMs maintain installed bases of PIC17C42A-25/PT-based equipment in industrial machinery, scientific instruments, and aerospace ground support where the original firmware is field-validated and certification-tested. Field replacement with the same Microchip part number preserves regulatory re-certification status. The NRND lifecycle status makes long-term supply critical to manage through authorised distributor buffer stocks and last-time-buy planning. Firmware compatibility ensures drop-in swap with no requalification overhead.
Được đề xuất
Display and Keypad Interfaces
Human-machine interface modules driving character LCDs, LED matrix displays, and 4x4 or 8x8 keypads are a strong fit for the PIC17C42A-25/PT. The 33 I/O pins comfortably handle 8-bit parallel LCD data buses, control signals, LED row/column drivers, and keypad scanning rows simultaneously. The 25 MHz clock provides responsive keypad debounce and LCD update rates, while 4 KB OTP holds custom character sets and menu navigation firmware. Designers frequently pair this MCU with HD44780-compatible LCD controllers.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho PIC17C42A-25/PT — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | PIC17C42A-25I/PT | PIC17C42A-16/PT | PIC17C42A-25/L | PIC17C44-25/PT | PIC18F4220-I/PT |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin TQFP (PT) | 44-pin TQFP (PT) - same | 44-pin TQFP (PT) - same | 44-pin PLCC (L) - different | 44-pin TQFP (PT) - same | 44-pin TQFP (PT) - same |
| Maximum Clock Input | 25 MHz | 25 MHz | 16 MHz | 25 MHz | 25 MHz | 40 MHz |
| Program Memory | 4 KB OTP | 4 KB OTP | 4 KB OTP | 4 KB OTP | 8 KB OTP | 32 KB Flash |
| RAM Size | 232 bytes | 232 bytes | 232 bytes | 232 bytes | 454 bytes | 2048 bytes |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 36 |
| Instruction Set Architecture | PIC17C (58 instructions) | PIC17C (58 instructions) | PIC17C (58 instructions) | PIC17C (58 instructions) | PIC17C (58 instructions) | PIC18 (75 instructions, recompile required) |
| Memory Type | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | Flash (reprogrammable) |
| Operating Temperature | 0 C to +70 C (commercial) | -40 C to +85 C (industrial) | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C | -40 C to +85 C (industrial) |
Bảo phân biệt quan trọng
- Highest clock speed in PIC17C42A TQFP-44 family (vsPIC17C42A-16/PT)
- Industrial temperature range variant available (vsPIC17C42A-25/PT (commercial))
- Double program memory upgrade path in same TQFP-44 (vsPIC17C42A-25/PT (4 KB))
Ghi chú thiết kế
PIC17C42A is OTP (one-time programmable) EPROM, NOT Flash. Once programmed the firmware cannot be erased or rewritten. Production units must be programmed with fully verified firmware; field firmware updates are impossible. Use a windowed ceramic package variant (if available) or a PIC17C42A-ICE emulator for development, and freeze the firmware revision before committing to OTP production units. Inventory costs increase because every firmware revision consumes new silicon.
Place decoupling capacitors within 6 mm of each VDD pin: a 100 nF ceramic in parallel with a 10 uF tantalum or ceramic bulk capacitor. The PIC17C42A's 25 MHz oscillator is sensitive to supply noise - inadequate decoupling causes erratic code execution and RAM corruption. Route the external crystal traces (OSC1/OSC2) as short, matched-length differential pairs with a ground guard trace. Keep the MCLR pull-up (typically 10 kohm to VDD) close to the pin to suppress reset glitches.
TQFP-44 has a 0.8 mm pitch, which requires 0.4 mm-wide traces with 0.2 mm clearance per IPC-2222 Class 2 standards. Use a 4-layer PCB with continuous ground plane beneath the MCU to control impedance and provide thermal dissipation. Place bulk capacitors on the same layer as the MCU if possible, and route VDD traces with at least 0.5 mm width to handle the MCU's inrush current during oscillator startup.
PIC17C42A typical operating current is approximately 15 mA at 25 MHz and 5 V per the datasheet. During EPROM programming cycles, peak current can spike to 50-100 mA. Ensure the voltage regulator has at least 20 percent headroom beyond steady-state consumption. Brown-out detection (BOR) is recommended for industrial applications to prevent code execution from corrupted memory during low-voltage events. Set BOR threshold per application voltage tolerance.
Thông tin tuân thủ
PIC17C42A is a legacy 1990s-era Microchip part. RoHS/REACH compliance documentation not surfaced in current public web data; buyers should request the latest material declaration directly from Microchip for production orders. Not AEC-Q100 qualified - PIC17C42A-25I/PT industrial variant extends temperature but does not carry automotive certification.