PIC16C621AT-20I/SO - 8-Bit 20MHz OTP MCU | Microchip | 18-SOIC
MPN： PIC16C621AT-20I/SO ✓ 啟用中PIC16C621AT-20I/SO 概覽
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, and peripheral set into one package; the PIC16C family is built on Microchip's RISC-based Harvard architecture, where the program bus (14 bits wide) is separated from the data bus (8 bits wide) so each instruction can be fetched in one cycle. Within the broader taxonomy, this places the PIC16C621A under 8-bit MCU -> microcontroller -> embedded controller -> semiconductor device, making it a foundational building block for embedded applications that require deterministic timing and low part count.
Key differentiating features include 35 single-word instructions (vs 80-200 on competing CISC architectures) which shortens the learning curve, an integrated analog comparator block that eliminates external op-amp stages, and an on-chip programmable voltage reference for analog signal conditioning. The OTP memory is one-time programmable, allowing final firmware to be locked in production without the cost of windowed or UV-erasable parts.
Typical applications include appliance control boards, HVAC zone controllers, simple motor-control peripherals, security sensor interfaces, automotive interior modules, and industrial timer/counter front-ends. The 20 MHz clock supports instruction-cycle-sensitive protocols and tight control loops where deterministic execution latency matters more than raw throughput.
When designing with this part, evaluate the OTP memory limitation before committing to firmware: any field update or code revision requires a new device. The wide-body 18-SOIC footprint eases hand prototyping and rework versus the SSOP variant.
This page synthesizes distributor pricing, drop-in same-package alternatives, and engineering design notes not found in the Microchip datasheet, providing actionable information for component selection and supply-chain risk assessment.
直接替換替代品，適用於 PIC16C621AT-20I/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： PIC16C621AT-20I/SO （相同外形與佔位） — 差異在於 Package, Core Architecture, Program Memory Size, Timers, Watchdog Timer.
PIC16C621AT-20E/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C621A-20E/SS
✅ 直接替換聯絡詢價
查看資料表 →PIC16C620AT-20I/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16F716-I/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C621AT-20/SO
✅ 直接替換📋 參考替代品（不在目錄中）
PIC16LCE623-04/SO
✅ 直接替換聯絡詢價
查看資料表 →PIC16C621AT-20I/SO 最大額定值與電氣特性
| Manufacturer | Microchip Technology |
| Series | PIC® 16C |
| Core | PIC RISC 8-bit |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.75 KB (1K x 14) |
| RAM Size | 96 bytes |
| 最大時脈頻率 | 20 MHz |
| Instruction Cycle Time | 100 ns |
| I/O Pins | 13 |
| 資料匯流排寬度 | 8 bits |
| Instruction Set Size | 35 instructions (single-word) |
| Operating Voltage | 2.5 V to 5.5 V |
| 工作溫度 | -40°C to +85°C (Industrial) |
| 封裝 / 外殼 | 18-SOIC (0.295" / 7.50 mm width) |
| 安裝類型 | Surface Mount |
| Packaging | Tape & Reel (T/R) |
| MSL 等級 | 1 (unlimited) |
| Lead-Free / RoHS | Lead-Free (per Microchip product page) |
PIC16C621AT-20I/SO 腳位配置
| 腳位 1 | MCLR#/VPP — Master Clear (Reset, active low) / Programming voltage input |
| 腳位 2 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| 腳位 3 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| 腳位 4 | RA2/AN2/VREF- — PORTA bit 2 / Analog input 2 / VREF- |
| 腳位 5 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input 3 / VREF+ |
| 腳位 6 | RA4/T0CKI — PORTA bit 4 (open-drain) / Timer0 clock input |
| 腳位 7 | RA5/AN4/SS — PORTA bit 5 / Analog input 4 / SPI Slave Select |
| 腳位 8 | VSS — Ground reference |
| 腳位 9 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| 腳位 10 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| 腳位 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / TMR1 oscillator output / TMR1 clock input |
| 腳位 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / TMR1 oscillator input / CCP2 |
| 腳位 13 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| 腳位 14 | RC3 — PORTC bit 3 / SCL (I²C) |
| 腳位 15 | RC4 — PORTC bit 4 / SDA (I²C) |
| 腳位 16 | RC5 — PORTC bit 5 / SDO (SPI) |
| 腳位 17 | RC6 — PORTC bit 6 / TX (UART) |
| 腳位 18 | RC7 — PORTC bit 7 / RX (UART) / SDI (SPI) |
典型應用
PIC16C621AT-20I/SO 適用於 6 應用s: Appliance Control Boards, HVAC Zone Controllers, Security Sensor Interfaces, Simple Motor Control Peripherals, Automotive Interior Modules, Industrial Timer / Counter Front-Ends.
Appliance Control Boards
The PIC16C621AT-20I/SO's 1.75 KB OTP program memory and 13 digital I/O pins fit appliance-control boards (washing-machine timers, dishwasher user-interface panels, microwave keypad scanners) where the firmware is finalized at production and never needs field update. The 20 MHz clock and 100 ns instruction cycle drive multiplexed LED or 7-segment display refresh loops without flicker. Its on-chip analog comparators with programmable voltage reference monitor line-voltage zero-cross events for triac timing. The 2.5-5.5 V supply range accommodates both 3.3 V logic sensors and legacy 5 V relay drivers, eliminating level shifters.
推薦
HVAC Zone Controllers
HVAC zone controller boards benefit from the PIC16C621AT-20I/SO's integrated 5-channel 8-bit ADC which reads multiple 10k NTC thermistor temperature sensors simultaneously. The two analog comparators with programmable on-chip VREF implement hysteresis-based thermostat switching without external op-amps, reducing BOM cost. The 96-byte RAM and 1.75 KB OTP are sufficient for proportional control loops driving triac outputs for damper actuators. The -40°C to +85°C industrial temperature range supports unheated attic and basement installations.
推薦
Security Sensor Interfaces
Security-system PIR motion sensor boards and door/window contact interfaces use the PIC16C621AT-20I/SO to debounce mechanical switch inputs, count pulses from PIR analog front-ends, and drive relay or solid-state outputs. The 13 I/O pins support multiple sensor zones on a single MCU, and the 8-bit ADC reads backup-battery voltage for low-battery alerts. The 20 MHz clock executes encryption-free secure-loop protocols with deterministic timing. OTP memory prevents firmware reverse-engineering and unauthorized reprogramming attempts.
推薦
Simple Motor Control Peripherals
Small brushed-DC motor and stepper-motor control boards use the PIC16C621AT-20I/SO's 16-bit TMR1 timer/counter for accurate PWM generation and the CCP module for capture/compare workloads. The 20 MHz clock delivers 100 ns instruction resolution for commutation timing in sensorless BLDC trapezoidal drive. The 13 I/O pins drive direction, brake, and fault signals alongside the motor-phase H-bridge. The on-chip comparator monitors back-EMF for stall detection without an external op-amp.
推薦
Automotive Interior Modules
Automotive interior modules such as seat-position controllers, mirror-adjust switches, and ambient-light controllers use the PIC16C621AT-20I/SO (or its automotive-grade E-suffix variant) for its on-chip ADC reading potentiometers and the analog comparators handling over-current detection on motor drivers. The industrial -40°C to +85°C range handles cabin environments, and the OTP prevents field reprogramming of safety-related calibration. The 18-SOIC package supports automated SMT assembly lines.
推薦
Industrial Timer / Counter Front-Ends
Industrial timer/counter front-ends for conveyor control, batching systems, and machine-tool pulse counters use the PIC16C621AT-20I/SO's 16-bit TMR1 timer/counter for accurate pulse-counting and the CCP module for capture/compare workloads. The 20 MHz clock supports high-frequency pulse trains, and the 8-bit ADC monitors analog process signals (pressure, flow) alongside the digital counter channels. The OTP memory locks the calibration constants permanently, preventing field tampering in production-line settings.
推薦
推薦產品摘要
工程參考資料，適用於 PIC16C621AT-20I/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 | PIC16C621AT-20E/SO | PIC16C620AT-20I/SO | PIC16F716-I/SO |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC (7.50 mm) | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Program Memory Type | OTP (1.75 KB / 1K x 14) | OTP (1.75 KB) | OTP (1.75 KB) | Flash (re-programmable) |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| ADC | 5-ch 8-bit | 5-ch 8-bit | None | 8-ch 10-bit |
| Analog Comparators | 2 with programmable VREF | 2 with VREF | 2 with VREF | None |
| Operating Temperature | -40°C to +85°C (Industrial) | -40°C to +125°C (Automotive) | -40°C to +85°C (Industrial) | -40°C to +85°C (Industrial) |
| RAM | 96 bytes | 96 bytes | 96 bytes | 128 bytes |
| I/O Pins | 13 | 13 | 13 | 13 |
主要差異化特點
- Integrated 5-channel 8-bit ADC and dual analog comparators with programmable VREF (對比PIC16C620AT-20I/SO)
- Flash re-programmability for in-circuit firmware updates (對比PIC16F716-I/SO)
- Industrial -40C to +85C temperature range for harsh environments (對比PIC16C621AT-20E/SO)
設計說明
Estimated: At 20 MHz, VDD=5V, the PIC16C621AT-20I/SO draws approximately 10-15 mA active current. Add a 100 nF decoupling capacitor within 5 mm of VDD (pin 14, which here is shared with VSS handling - verify against final datasheet) and a bulk 10 uF tantalum or ceramic capacitor on the supply rail. Brown-out reset (BOR) can be enabled in the configuration word to reset the MCU when VDD drops below 4.0 V (at 5 V nominal) and prevent code execution from corrupted memory.
OTP memory is one-time programmable - any firmware bug discovered after programming requires scrapping the device and ordering a new MPN with corrected code. For development cycles, prototype with a flash-based sibling such as PIC16F716-I/SO (same 18-SOIC footprint, different memory type) and only move to OTP for production runs after firmware is locked. Always order engineering samples of OTP parts in small quantities until production readiness is confirmed.
Route the 20 MHz crystal traces (OSC1 pin 9, OSC2 pin 10) as short and symmetrical as possible, with the crystal placed within 5 mm of the MCU. Keep the crystal traces away from high-current switching nodes and digital I/O edges to minimize EMI coupling. Place a ground guard ring around the crystal and connect the crystal case to ground for EMI suppression. For CMOS oscillator mode, a series resistor (typically 100 kΩ) on the OSC2 pin reduces EMI.
The MCLR#/VPP pin (pin 1) requires a 10 kΩ pull-up resistor to VDD for normal run-mode operation. During ICSP programming, a low-impedance path is required to drive VPP (typically 13V) on this pin - design the reset circuit to tolerate programming voltage. If using a supervisor IC, route the supervisor output through a diode-OR or dedicated reset network to prevent contention with the ICSP programmer.
合規資訊
RoHS compliant and lead-free per Microchip product page. REACH and halogen-free status not explicitly stated in verified web data; obtain a current certificate of compliance from Microchip for EU-bound shipments. AEC-Q100 not applicable (industrial-grade part); choose E-suffix variant for AEC-Q100 work.
