PIC16C66T-20/SO - 8-Bit 20MHz OTP MCU 14KB | Microchip
MPN： PIC16C66T-20/SO ✗ 停產PIC16C66T-20/SO 概覽
A microcontroller (MCU) is a single-chip computer containing a CPU core, non-volatile program memory, working RAM, and programmable I/O peripherals. Within the broader taxonomy, the PIC16C66 sits as a mid-range 8-bit MCU under Microchip's classic PIC16C OTP family, which was widely adopted in the late 1990s and early 2000s for cost-sensitive embedded control. The 8-bit RISC Harvard architecture executes 35 single-word instructions, with all instructions completing in one cycle except program branches (two cycles), giving an effective throughput close to one instruction per clock.
Key features of the PIC16C66T-20/SO include 22 digital I/O pins arranged across multiple ports, three timer/counter modules (Timer0, Timer1, and Timer2), a synchronous serial port configurable as SPI or I2C, a USART for asynchronous serial communication, an 8-bit ADC with up to 8 input channels, and a capture/compare/PWM (CCP) module. The device supports DC to 20 MHz clock input across a 2.5 V to 6.0 V supply range, integrated power-on reset, brown-out reset, watchdog timer with dedicated oscillator, and programmable code protection.
The PIC16C66's architecture separates program and data buses (Harvard), allowing instruction fetch and data access to occur in the same clock cycle. This yields deterministic instruction timing that simplifies real-time control. OTP program memory enables rapid prototyping with one-week-turn ROM mask follow-up for production volumes - a design pattern Microchip promoted throughout the 1990s industrial and appliance market.
Typical applications include appliance controllers (washing machines, microwave ovens, HVAC thermostats), industrial automation (sensor conditioning, motor speed control), automotive body electronics (window lift, seat control, instrument cluster peripherals), consumer electronics (remote controls, toys, small appliances), and embedded data-acquisition front-ends. The 22 I/O and 8-channel ADC are well-matched to multi-sensor control boards requiring both analog measurement and digital actuation.
When designing with this part, note that OTP memory cannot be reprogrammed in-circuit, so firmware must be validated on a windowed (UV-erasable) PIC16C66-20/JW or PIC16F-series flash equivalent before committing to OTP production units. Always provide bulk decoupling (100 nF plus 10 uF) close to VDD/VSS and reserve the MCLR pin for a proper reset network to avoid spurious brown-out events.
This page synthesizes distributor pricing, drop-in PIC16C66 family variants, and practical design considerations not collected in the original 1990s Microchip datasheet.
直接替換替代品，適用於 PIC16C66T-20/SO — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： PIC16C66T-20/SO （相同外形與佔位） — 差異在於 Package, ADC, Timers, Program Memory Type, Watchdog Timer.
PIC16C66-20/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C66T-10/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C66T-10E/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C66-20I/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C66-04I/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C66-20/SP
✅ 直接替換聯絡詢價
查看資料表 →PIC16F876A-I/SO
✅ 直接替換📋 參考替代品（不在目錄中）
PIC16C66T-20/SO 最大額定值與電氣特性
| Core Architecture | 8-bit PIC RISC (Harvard) |
| Family | PIC16C6X (mid-range OTP) |
| Instruction Set | 35 single-word instructions |
| Max CPU Clock | 20 MHz |
| Program Memory | 14 KB (8K x 14) OTP |
| RAM | 368 bytes |
| I/O Pins | 22 |
| ADC | 8-bit, up to 8 channels |
| Timers | 3 (Timer0, Timer1, Timer2) |
| Serial Interfaces | SSP (SPI/I2C) + USART |
| CCP Module | 1 (Capture/Compare/PWM) |
| Operating Voltage | 2.5 V to 6.0 V |
| 工作溫度 | 0C to +70C (Commercial) |
| 封裝 | 28-SOIC (7.50 mm body width, gull wing) |
| Watchdog Timer | Yes, dedicated WDT oscillator |
| Brown-out Reset | Yes |
| Power-on Reset | Yes |
| Program Code Protection | Yes (programmable) |
PIC16C66T-20/SO 腳位配置
| 腳位 1 | MCLR/VPP — Master Clear (Reset) input / programming voltage |
| 腳位 2 | RA0/AN0 — PORTA bit 0 / ADC input 0 |
| 腳位 3 | RA1/AN1 — PORTA bit 1 / ADC input 1 |
| 腳位 4 | RA2/AN2 — PORTA bit 2 / ADC input 2 |
| 腳位 5 | RA3/AN3/VREF — PORTA bit 3 / ADC input 3 / VREF+ |
| 腳位 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| 腳位 7 | RA5/AN4/SS — PORTA bit 5 / ADC input 4 / SPI slave select |
| 腳位 8 | OSC1/CLKIN — Oscillator crystal input / external clock in |
| 腳位 9 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| 腳位 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock |
| 腳位 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| 腳位 12 | RC2/CCP1 — PORTC bit 2 / Capture Compare PWM 1 |
| 腳位 13 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| 腳位 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| 腳位 15 | RC5/SDO — PORTC bit 5 / SPI data out |
| 腳位 16 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| 腳位 17 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| 腳位 18 | VSS — Ground reference |
| 腳位 19 | VDD — Positive supply voltage |
| 腳位 20 | RB0/INT — PORTB bit 0 / external interrupt |
| 腳位 21 | RB1 — PORTB bit 1 |
| 腳位 22 | RB2 — PORTB bit 2 |
| 腳位 23 | RB3/PGM — PORTB bit 3 / low-voltage programming |
| 腳位 24 | RB4 — PORTB bit 4 |
| 腳位 25 | RB5 — PORTB bit 5 |
| 腳位 26 | RB6/PGC — PORTB bit 6 / ICSP clock |
| 腳位 27 | RB7/PGD — PORTB bit 7 / ICSP data |
| 腳位 28 | VSS — Ground reference |
典型應用
PIC16C66T-20/SO 適用於 6 應用s: Appliance Control (White Goods), Industrial Sensor Conditioning and Control, Automotive Body Electronics (Legacy Modules), Consumer Electronics Remote and User Interface, HVAC Thermostat and Environmental Controller, Embedded Data Acquisition Front-End.
Appliance Control (White Goods)
The PIC16C66T-20/SO fits white-goods appliance controllers - washing machines, dishwashers, and microwave ovens - because its 22 I/O pins can directly drive relay coils, triac gate interfaces, and seven-segment LED or VFD displays. The 20 MHz RISC core delivers deterministic cycle timing needed for triac zero-crossing and motor PWM commutation, while the 8-bit ADC with eight channels reads thermistor, water-level, and door-switch sensors without external multiplexing. Built-in brown-out and watchdog timer with a dedicated oscillator protect against mains-brown-out misoperation in noisy power environments. The commercial 0C-70C temperature range suits indoor appliance enclosures.
推薦
Industrial Sensor Conditioning and Control
Industrial sensor-front-end boards leverage the PIC16C66T-20/SO's 22 digital I/O and 8-bit, 8-channel ADC to scan thermistor, pressure, and 4-20 mA loop transducers while outputting PWM or analog control signals to actuators. The 20 MHz core enables up to 5 kHz ADC sampling, sufficient for closed-loop motor speed, hydraulic proportional valve, or PID temperature control loops. SSP plus USART peripherals allow SPI/I2C inter-MCU networking or RS-232/485 host communication. Brown-out reset and watchdog timer with dedicated oscillator ensure reliable recovery from industrial EMI events.
推薦
Automotive Body Electronics (Legacy Modules)
Legacy automotive body modules - window lift, seat position, mirror adjustment, and instrument-cluster peripherals - used the PIC16C66T-20/SO because its 22 I/O drive the H-bridge enable and direction lines plus feedback encoder inputs. The PIC16C6X family's 14 KB OTP was adequate for state-machine control code while the 368-byte RAM held running encoder counters. Although the part is NRND and not AEC-Q100 qualified, modules already in production continue to use it; new automotive designs should migrate to the AEC-Q100-qualified PIC18F family.
推薦
Consumer Electronics Remote and User Interface
Consumer remote controls, small appliances, and toys benefit from the PIC16C66T-20/SO's low-cost OTP memory and built-in USART for IR or RF link protocols. The 22 I/O directly scan matrix keypads up to 8x8 or drive LCD segments without external logic, and the 20 MHz cycle supports bit-banged Manchester or RC5/RC6 IR carrier generation. The 8-bit ADC reads battery voltage and trim pots. Brown-out reset prevents lockup on weak batteries, extending user-replaceable battery life in handheld products.
推薦
HVAC Thermostat and Environmental Controller
HVAC thermostat and environmental-controller boards use the PIC16C66T-20/SO to read multiple thermistor temperature sensors via the 8-bit ADC, drive triac-controlled fan speeds via PWM on the CCP module, and communicate with indoor units over USART or SSP. The 14 KB OTP holds look-up tables for proportional control curves and scheduler state, while 368 bytes of RAM buffers setpoint and sensor history. Brown-out reset protects the controller during compressor inrush events that briefly sag the supply rail.
推薦
Embedded Data Acquisition Front-End
Embedded 8-channel data-acquisition front-ends pair the PIC16C66T-20/SO with external analog multiplexers or sensor bridges, using its ADC to digitize, the USART to stream packets to a host PC, and the SSP to log to external EEPROM. The 20 MHz core supports up to 5 kHz aggregate sample rate across eight channels - well-matched to industrial process monitoring of slowly varying signals such as strain gauge, RTD, or pH probe inputs. Watchdog timer with dedicated oscillator protects unattended logger installations against firmware lockup.
推薦
推薦產品摘要
工程參考資料，適用於 PIC16C66T-20/SO — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | PIC16C66-20/SO | PIC16C66T-10/SO | PIC16C66-20I/SO | PIC16C66-04I/SO | PIC16F876A-I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Max Clock | 20 MHz | 20 MHz | 10 MHz | 20 MHz | 4 MHz | 20 MHz |
| Program Memory | 14 KB OTP | 14 KB OTP | 14 KB OTP | 14 KB OTP | 14 KB OTP | 8 KB Flash |
| RAM | 368 bytes | 368 bytes | 368 bytes | 368 bytes | 368 bytes | 368 bytes |
| I/O Pins | 22 | 22 | 22 | 22 | 22 | 22 |
| ADC | 8-bit, 8-ch | 8-bit, 8-ch | 8-bit, 8-ch | 8-bit, 8-ch | 8-bit, 8-ch | 10-bit, 8-ch |
| Temperature Grade | Commercial 0C-70C | Commercial 0C-70C | Commercial 0C-70C | Industrial -40C to +85C | Industrial -40C to +85C | Industrial -40C to +85C |
| Memory Type | OTP | OTP | OTP | OTP | OTP | Flash |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND | Active |
主要差異化特點
- Tape-and-reel packaging for high-volume automated assembly (對比PIC16C66-20/SO)
- Pin-compatible flash upgrade path to PIC16F876A-I/SO (對比PIC16F876A-I/SO)
- Industrial temperature variant available in same package (對比PIC16C66-20I/SO)
設計說明
Place a 100 nF ceramic decoupling capacitor within 5 mm of the VDD pin (pin 20) and a 10 uF bulk tantalum or aluminum electrolytic on the same supply trace. The PIC16C66T-20/SO has separate analog (VDD) and digital VSS pins; both must be returned to a low-impedance ground plane. Estimated: with 22 I/O lines switching simultaneously at 20 MHz, peak transient current can reach 80 mA - the bulk capacitor prevents supply droop that would corrupt ADC conversions.
The PIC16C66T-20/SO uses One-Time Programmable memory that cannot be erased or rewritten. Validate firmware on a windowed (UV-erasable) PIC16C66-20/JW or a flash-based PIC16F876A-I/SO (pin-compatible) before committing to OTP production. Failed OTP units are scrap - there is no recovery path. Always order a 5-10% overage to cover programming rejects and field returns.
Route the oscillator traces (OSC1/OSC2, pins 8-9) as short, symmetrical lengths with the crystal and load capacitors placed within 5 mm of the MCU. Keep high-current switching traces (relay coils, triac gates) at least 10 mm away from the analog ADC inputs (RA0-RA5) to avoid conducted/coupled noise. A single-point ground where analog VSS and digital VSS meet at the regulator prevents ground-loop ADC errors.
The PIC16C66's 8-bit ADC draws approximately 500 uA of analog supply current during conversion - this can droop the VDD rail if the source impedance exceeds 10 ohms. Use a separate low-pass RC (10 ohm + 10 uF) on AVdd/AVss if available, or decouple the VDD pin with at least 10 uF bulk plus 100 nF ceramic. Sample-and-hold acquisition time must be programmed to a minimum of 19.2 us per the datasheet for 10-bit accuracy (or 4 us for 8-bit) to avoid ADC channel-to-channel crosstalk.
合規資訊
RoHS compliant per Microchip product page and DigiKey listing. The PIC16C6X family is NRND (Not Recommended for New Designs) as of 2026-09-18 - new automotive programs should select AEC-Q100-qualified PIC18F/K devices instead.
