PIC16C74A-20I/PQ - 8-Bit 20MHz 7KB OTP MCU 44-MQFP | Microchip
MPN: PIC16C74A-20I/PQ ✗ Cuối đờiPIC16C74A-20I/PQ Tóm tắt
What is a PIC mid-range microcontroller? PIC microcontrollers are RISC-based 8-bit CMOS MCUs from Microchip Technology built on a Harvard architecture that separates program and data memory. The "mid-range" PIC16 family sits between baseline PIC10/12/16 and enhanced PIC18 devices, balancing instruction density, peripheral integration, and cost. Each instruction word is 14 bits wide and most execute in a single cycle, giving 20 MHz PICs roughly 5 MIPS of throughput - ideal for motor control, instrumentation, and consumer-electronics applications.
Key features include the 44-pin Metric QFP (MQFP 10x10mm) surface-mount footprint, industrial -40C to +85C temperature grade (denoted by the "I" suffix), and brown-out reset / power-on reset / watchdog timer for robust field reliability. The device is windowed-EPROM/OTP based, making it suitable for prototyping and low-to-medium volume production. Its 33 I/O pins can source/sink up to 25 mA each, sufficient for direct LED and relay drive in many control circuits.
Technically, the PIC16C74A implements a 14-bit instruction set with an 8-level hardware stack, vectored interrupts, and a multiplier that performs 8x8 in one cycle. The integrated 12-channel 8-bit ADC can be used for sensor conditioning; the USART enables RS-232/RS-485 communications. Compared to its predecessor PIC16C74, the -A silicon revision adds improved ADC accuracy and an extended instruction set.
Typical applications include industrial process control, sensor signal acquisition, motor drive control, automotive body electronics, security systems, and embedded instrumentation. The wide operating voltage and -40C to +85C industrial temperature range also suit HVAC controllers and machine-tool interfaces.
When designing with this device, ensure adequate decoupling (100 nF per supply pin plus a 10 uF bulk capacitor), reserve a 4-pin ICP header for in-circuit programming, and confirm that your supply stays within the 4.0V to 6.0V range. Note that the part is OTP - firmware is fixed at the first programming cycle.
This page synthesizes distributor availability, drop-in PIC16C74B and PIC16F74 flash-based upgrades, and practical design notes beyond what the manufacturer datasheet alone offers.
Bộ thay thế dễ dàng lắp đặt cho PIC16C74A-20I/PQ — 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 PIC16C74A-20I/PQ (cùng hình factor và footprint) — khác nhau ở Package, Serial Interfaces, Watchdog Timer, Timers, ADC.
PIC16C74A-20/PQ
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC16C74A-20E/PQ
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC16C74A-04/PQ
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC16F74-I/PT
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC16F877-20I/PQ
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →PIC16C74A-20I/PQ Tỷ lệ tối đa & tính chất điện
| Core | PIC16 (8-bit RISC) |
| Instruction Set Architecture | 14-bit (PIC16C7X mid-range) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 7 KB (4K x 14) |
| RAM | 192 bytes |
| Data EEPROM | Not present (none) |
| Maximum CPU Clock | 20 MHz |
| Instruction Throughput | 5 MIPS @ 20 MHz |
| Operating Voltage (Vdd) | 4.0 V to 6.0 V |
| I/O Pins | 33 |
| ADC | 12-channel, 8-bit |
| Timers | Timer0 (8-bit) + Timer1 (16-bit) + Timer2 (8-bit) |
| CCP Module | 1 x 16-bit Capture/Compare/PWM |
| USART | 1 (synchronous/asynchronous) |
| Parallel Port | 8-bit (PORTD/PORTE-style) |
| Watchdog Timer | Yes (independent WDT) |
| Brown-out Reset / Power-on Reset | Yes |
| Nhiệt độ hoạt động | -40C to +85C (industrial, "I" grade) |
| Hộp | 44-pin Metric QFP (MQFP 10x10 mm) |
| Kiểu lắp đặt | Surface Mount |
| Trạng thái RoHS | Non-compliant (OTP/EPROM legacy windowed part) |
| Per-pin Source/Sink Current | 25 mA |
Cấu hình chân PIC16C74A-20I/PQ
| Chân 1 | MCLR/Vpp — Master Clear (Reset) input / programming voltage |
| Chân 2 | OSC1/CLKI — Oscillator input / external clock input |
| Chân 3 | OSC2/CLKO — Oscillator output |
| Chân 4 | RC0/T1OSO/T1CKI — Digital I/O / Timer1 oscillator output / Timer1 clock input |
| Chân 5 | RC1/T1OSI/CCP2 — Digital I/O / Timer1 oscillator input / CCP2 output |
| Chân 6 | RC2/CCP1 — Digital I/O / CCP1 output |
| Chân 7 | RC3/SCK/SCL — Digital I/O / SSP SPI clock / I2C clock |
| Chân 8 | RD0/PSP0 — Digital I/O / Parallel Slave Port bit 0 |
| Chân 9 | RD1/PSP1 — Digital I/O / Parallel Slave Port bit 1 |
| Chân 10 | RD2/PSP2 — Digital I/O / Parallel Slave Port bit 2 |
| Chân 11 | RD3/PSP3 — Digital I/O / Parallel Slave Port bit 3 |
| Chân 12 | RC4/SDI/SDA — Digital I/O / SSP SPI data in / I2C data |
| Chân 13 | RC5/SDO — Digital I/O / SSP SPI data out |
| Chân 14 | RC6/TX/CK — Digital I/O / USART TX / USART clock |
| Chân 15 | RC7/RX/DT — Digital I/O / USART RX / USART data |
| Chân 16 | RD4/PSP4 — Digital I/O / Parallel Slave Port bit 4 |
| Chân 17 | RD5/PSP5 — Digital I/O / Parallel Slave Port bit 5 |
| Chân 18 | RD6/PSP6 — Digital I/O / Parallel Slave Port bit 6 |
| Chân 19 | RD7/PSP7 — Digital I/O / Parallel Slave Port bit 7 |
| Chân 20 | Vss — Ground |
| Chân 21 | Vdd — Positive supply (4.0V to 6.0V) |
| Chân 22 | RB0/INT — Digital I/O / external interrupt |
| Chân 23 | RB1 — Digital I/O |
| Chân 24 | RB2 — Digital I/O |
| Chân 25 | RB3 — Digital I/O |
| Chân 26 | RB4 — Digital I/O / interrupt-on-change |
| Chân 27 | RB5 — Digital I/O / interrupt-on-change |
| Chân 28 | RB6/PGC — Digital I/O / ICSP clock / interrupt-on-change |
| Chân 29 | RB7/PGD — Digital I/O / ICSP data / interrupt-on-change |
| Chân 30 | RE0/RD — Digital I/O / parallel port read |
| Chân 31 | RE1/WR — Digital I/O / parallel port write |
| Chân 32 | RE2/CS — Digital I/O / parallel port chip select |
| Chân 33 | Vss — Ground |
| Chân 34 | Vdd — Positive supply (4.0V to 6.0V) |
| Chân 35 | RA0/AN0 — Digital I/O / analog input channel 0 |
| Chân 36 | RA1/AN1 — Digital I/O / analog input channel 1 |
| Chân 37 | RA2/AN2 — Digital I/O / analog input channel 2 |
| Chân 38 | RA3/AN3/Vref+ — Digital I/O / analog input channel 3 / ADC positive reference |
| Chân 39 | RA4/T0CKI — Digital I/O / Timer0 clock input |
| Chân 40 | RA5/AN4/SS — Digital I/O / analog input channel 4 / SSP slave select |
| Chân 41 | Vss — Ground |
| Chân 42 | Vdd — Positive supply (4.0V to 6.0V) |
| Chân 43 | NC — Not connected (per datasheet) |
| Chân 44 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
PIC16C74A-20I/PQ phù hợp cho 7 Áp dụngs: Industrial Process Control, Sensor Signal Acquisition Module, Stepper Motor Drive Controller, HVAC Building Automation, Security and Access Control Panels, Automotive Body Electronics (Legacy), Embedded Instrumentation and Test Gear.
Industrial Process Control
The PIC16C74A-20I/PQ's 33 I/O pins, 12-channel 8-bit ADC, and 5 MIPS throughput make it a strong fit for industrial process controllers monitoring temperature, pressure, and flow sensors. Its -40C to +85C industrial temperature grade suits factory-floor enclosures, while the USART provides RS-485 connectivity to remote SCADA nodes. The OTP memory architecture is well-matched to mature, stable firmware that does not require field updates. A typical design uses the 16-bit CCP module to drive an SSR/relay output for heater control, with 4 ADC channels measuring thermocouple inputs through external op-amp conditioning. The 44-pin MQFP package offers ample ground and supply pins for noise immunity in electrically noisy plant environments.
Được đề xuất
Sensor Signal Acquisition Module
With 12-channel 8-bit ADC and 5 MIPS throughput, the PIC16C74A-20I/PQ is purpose-built for multi-channel sensor acquisition boards reading 4-20 mA loops, thermistors, or photodiodes. The 33 I/O lines allow each channel to include a dedicated digital output for sensor power switching, while the USART streams data to a host PLC or display. The 20 MHz clock samples each ADC channel within microseconds, enabling oversampling techniques to improve effective resolution. Industrial temperature range and brown-out reset support reliable operation in 24V factory environments. This usage pattern remains common in environmental monitoring stations and HVAC sensor hubs.
Được đề xuất
Stepper Motor Drive Controller
The PIC16C74A-20I/PQ is widely deployed as a stepper motor indexer in low-cost CNC, 3D-printer, and small-automation equipment. Its 16-bit CCP module generates precise step pulses, while two 8-bit timers drive acceleration/deceleration profiles. The 33 digital I/O pins can directly source up to 25 mA each - enough to drive optocouplers feeding a discrete MOSFET H-bridge without extra driver ICs. 5 MIPS throughput at 20 MHz allows trapezoidal-velocity profile computation in real time. The OTP memory ensures firmware integrity in vibration-prone industrial environments. Choose the PIC16F74-I/PT (flash) for designs requiring firmware tuning after deployment.
Được đề xuất
HVAC Building Automation
The PIC16C74A-20I/PQ's industrial -40C to +85C temperature rating, on-chip ADC, and USART make it suitable for HVAC zone controllers and rooftop unit thermostats. It can read multiple 10k NTC thermistor inputs, control damper servo motors via PWM, and drive triac optocouplers for compressor control. The OTP memory fits HVAC firmware that is rarely updated once qualified. The 44-pin Metric QFP package has strong second-source availability, critical for the 10+ year service life of commercial HVAC equipment. Migration path to PIC16F74-I/PT is straightforward because both share identical peripheral sets and pin assignments.
Được đề xuất
Security and Access Control Panels
The PIC16C74A-20I/PQ is a proven workhorse in legacy security alarm panels and access-control systems, where it scans up to 12 zones of PIR/door-contact sensors via its 12-channel ADC and digital I/O. The USART links to a central monitoring station over dial-up or GSM, and the CCP module can drive a piezo siren. Industrial temperature grade and robust brown-out reset provide the field reliability security applications demand. OTP memory prevents post-deployment firmware tampering - desirable in some regulated security markets. Modernization typically pairs this part with a wireless modem or Ethernet bridge.
Được đề xuất
Automotive Body Electronics (Legacy)
Although not AEC-Q100 qualified, the PIC16C74A-20I/PQ has been used extensively in non-safety automotive body-electronics modules such as seat controllers, mirror adjusters, and aftermarket instrumentation where its -40C to +85C rating suffices for cabin environments. The 33 I/O pins can directly drive LEDs and small relays via 25 mA per-pin drive, and the 12-channel ADC reads resistive sensor inputs (e.g., potentiometer-driven mirrors). New automotive designs should select AEC-Q100-qualified dsPIC33 or PIC18 K-series devices instead. The PIC16F74-I/PT also lacks AEC-Q100 status, so a true automotive migration requires a more substantive MCU swap.
Được đề xuất
Embedded Instrumentation and Test Gear
With 5 MIPS throughput, 192 B RAM, and a USART for streaming digitized measurements, the PIC16C74A-20I/PQ is at home in low-cost bench-top instruments like handheld multimeters, capacitance meters, and educational oscilloscope front-ends. The 12-channel 8-bit ADC captures analog signals from sensor or probe conditioning networks, while the 16-bit CCP module generates timing waveforms for measurement stimuli. Industrial temperature grade and OTP program memory suit rugged field instruments. For designs requiring USB or higher-speed ADC, the PIC16F877-20I/PQ is a related drop-in with flash memory and additional peripherals.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho PIC16C74A-20I/PQ — 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 | PIC16C74A-20/PQ | PIC16C74A-20E/PQ | PIC16F74-I/PT | PIC16F877-20I/PQ | PIC16C74A-04/PQ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin MQFP (10x10 mm) | 44-pin MQFP (10x10 mm) - same | 44-pin MQFP (10x10 mm) - same | 44-pin TQFP (10x10 mm) - same footprint | 44-pin MQFP (10x10 mm) - same | 44-pin MQFP (10x10 mm) - same |
| Program Memory Type | OTP EPROM | OTP EPROM - same | OTP EPROM - same | Flash (reprogrammable via ICSP) | Flash (reprogrammable via ICSP) | OTP EPROM - same |
| Program Memory Size | 7 KB (4K x 14) | 7 KB - same | 7 KB - same | 7 KB - same | 14 KB (+100%) | 7 KB - same |
| Max CPU Clock | 20 MHz | 20 MHz - same | 20 MHz - same | 20 MHz - same | 20 MHz - same | 4 MHz (-80%) |
| RAM | 192 bytes | 192 bytes - same | 192 bytes - same | 192 bytes - same | 368 bytes (+92%) | 192 bytes - same |
| I/O Pins | 33 | 33 - same | 33 - same | 33 - same | 33 - same | 33 - same |
| ADC | 12-ch x 8-bit | 12-ch x 8-bit - same | 12-ch x 8-bit - same | 8-ch x 8-bit (-33% channels) | 8-ch x 10-bit (higher resolution, fewer channels) | 12-ch x 8-bit - same |
| Temperature Grade | Industrial -40C to +85C ("I") | Commercial 0C to +70C | Extended -40C to +125C ("E") | Industrial -40C to +85C ("I") - same | Industrial -40C to +85C ("I") - same | Commercial 0C to +70C |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Active (recommended replacement) | Active | Obsolete |
Bảo phân biệt quan trọng
- Industrial temperature grade with 33 I/O and 5 MIPS throughput (vsPIC16C74A-20/PQ (commercial temp))
- Higher operating frequency than the 04 speed grade (vsPIC16C74A-04/PQ)
- 12-channel 8-bit ADC vs 8-channel on flash-based drop-in (vsPIC16F74-I/PT)
- 12-channel 8-bit ADC with high channel count for sensor designs (vsPIC16F877-20I/PQ (8-ch 10-bit))
Ghi chú thiết kế
The PIC16C74A-20I/PQ runs from a single 4.0 V to 6.0 V supply. Estimated: at Vdd = 5 V and 20 MHz with all peripherals active, the device draws roughly 30 mA (mostly I/O switching). Place a 100 nF ceramic decoupling capacitor within 5 mm of each Vdd/Vss pair (the MQFP has multiple Vdd/Vss pins) plus a 10 uF bulk capacitor on the supply rail. The brown-out reset threshold is ~4.0 V; ensure your regulator maintains >4.0 V under full load.
The 44-pin MQFP package has a thermal resistance (theta_JA) of approximately 80 C/W on a 1-oz 4-layer PCB. Estimated: at 5 V x 30 mA = 150 mW dissipation, junction rise is only ~12 C above ambient - well within the 150 C maximum. In enclosed industrial housings above 60 C ambient, however, derate operating frequency or ensure airflow. Industrial -40 C to +85 C operating range and 150 C max junction remain the dominant thermal limits.
Route the 20 MHz oscillator traces (OSC1/OSC2) symmetrically with ground shielding on both sides and keep them under 10 mm. Place decoupling capacitors with the shortest possible loop to the Vdd/Vss pins. The RB6/PGC and RB7/PGD pins must reach an ICSP header with no series resistors; the Microchip ICD programmers expect direct connection. If using PORTE for parallel slave port, leave at least 0.5 mm clearance to adjacent signal traces for crosstalk protection.
Common pitfalls when using the PIC16C74A-20I/PQ: (1) OTP memory is one-time programmable - you cannot erase and re-flash, so always verify code on a PIC16F74 breadboard first. (2) Some PIC16F74 variants reduce ADC channels from 12 to 8 - confirm your code does not rely on channels AN5-AN11. (3) MCLR must not float; tie it to Vdd through a 10 kohm resistor with a 100 nF decoupling cap to ground for noise immunity. (4) The I/O pin current of 25 mA applies per pin, not in aggregate; total Vdd current is limited to ~250 mA package total.
Thông tin tuân thủ
Legacy OTP/EPROM part - typically not RoHS compliant. Not AEC-Q100 qualified; Microchip has not published automotive PPAP for the PIC16C74A family. New automotive designs should select dsPIC33 or PIC18 K-series devices.
