PIC16C642-20I/SP - 8-Bit 20MHz 7KB OTP MCU 28-SPDIP | Microchip
MPN: PIC16C642-20I/SP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.95 | $8.95 |
| 10 | $8.06 | $80.60 |
| 100 | $7.16 | $716.00 |
| 500 | $6.27 | $3,135.00 |
| 1,000 | $5.37 | $5,370.00 |
PIC16C642-20I/SP Overview
What is an 8-bit microcontroller? An 8-bit microcontroller is a small computer-on-a-chip integrating a CPU, RAM, ROM/EPROM/Flash program memory, and I/O peripherals on a single die. The 8-bit PIC microcontroller family from Microchip sits within the broader category of microcontrollers (MCU), which are themselves a subset of embedded processors. The PIC16C series in particular uses a RISC (Reduced Instruction Set Computer) architecture with only 35 single-word instructions, making code development and debugging faster than CISC alternatives.
Key features include two analog comparators with a programmable on-chip voltage reference, an 8-bit timer/counter (TMR0) with 8-bit programmable prescaler, a Watchdog Timer with its own on-chip RC oscillator for reliable operation, and a power-saving Sleep mode. The device offers 22 I/O pins with high-current sink/source capability, an internal oscillator option on some variants, and brown-out reset protection. The 'I' suffix denotes the industrial temperature range (-40C to +85C), and 'SP' designates the SPDIP-28 package.
The PIC16C642-20I/SP implements a Harvard architecture with separate program and data buses, enabling simultaneous instruction fetch and operand access. Its OTP EPROM program memory is windowed for prototype verification but is not reprogrammable in-circuit, making the device suitable for production runs where code is finalized. The integrated analog comparators eliminate the need for external op-amp stages in threshold-detection circuits.
Typical applications include appliance control (washing machines, microwave ovens), security systems, motor control (small DC and stepper drives), automotive body electronics, HVAC thermostats, and industrial process controllers. The industrial temperature grade makes it particularly well-suited for factory-floor equipment and outdoor installations.
When designing with this device, note that OTP memory cannot be reprogrammed; engineering samples or QTP (qualified third-party programming) services are needed for prototype validation. The 28-SPDIP package requires through-hole PCB mounting, which is less assembly-friendly than surface-mount alternatives but offers easier hand-prototyping and field replacement.
This page synthesizes distributor pricing, validated drop-in alternatives from the same Microchip PIC16C family, and practical design notes not found on the manufacturer datasheet cover page.
Drop-in alternatives for PIC16C642-20I/SP — 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 PIC16C642-20I/SP (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, Maximum Clock Frequency, Mounting Type, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C642-20/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C642-20E/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C642-04I/SP
✅ Drop-In✓ In Stock
$4.95 / Unit
View Datasheet →PIC16C642-04/SO
✅ Drop-In✓ In Stock
$4.3 / Unit
View Datasheet →PIC16C642-04E/SP
✅ Drop-In✓ In Stock
$5.65 / Unit
View Datasheet →PIC16C642-20I/SP Maximum Ratings & Electrical Characteristics
| Product Family | PIC16C Series |
| Core Architecture | 8-bit RISC (Harvard) |
| Instruction Set | 35 single-word instructions |
| Program Memory Size | 7KB (4K x 14-bit) OTP EPROM |
| RAM Size | 176 bytes |
| Data EEPROM | Not present |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Supply Voltage Range | 4.0 V to 5.5 V |
| I/O Pins | 22 |
| Analog Comparators | 2 with programmable voltage reference |
| Timers | TMR0 (8-bit with prescaler), WDT with dedicated RC oscillator |
| Package Type | 28-pin SPDIP (0.300 inch, 7.62 mm) |
| Operating Temperature | -40C to +85C (Industrial, 'I' suffix) |
| Mounting Type | Through-Hole |
| Program Memory Type | OTP (One-Time Programmable) EPROM, windowed |
| RoHS Status | Check distributor listing |
PIC16C642-20I/SP Pin Configuration
| Pin 1 | RA2/AN2 — Port A bit 2 / analog input 2 |
| Pin 2 | RA3/AN3 — Port A bit 3 / analog input 3 |
| Pin 3 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 4 | RA5/SS — Port A bit 5 / slave select |
| Pin 5 | VDD — Positive supply voltage |
| Pin 6 | VSS — Ground |
| Pin 7 | OSC1/CLKIN — Oscillator crystal input / external clock |
| Pin 8 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| Pin 9 | RC0 — Port C bit 0 |
| Pin 10 | RC1 — Port C bit 1 |
| Pin 11 | RC2 — Port C bit 2 |
| Pin 12 | RC3 — Port C bit 3 |
| Pin 13 | RC4 — Port C bit 4 |
| Pin 14 | RC5 — Port C bit 5 |
| Pin 15 | RC6 — Port C bit 6 |
| Pin 16 | RC7 — Port C bit 7 |
| Pin 17 | RB0/INT — Port B bit 0 / external interrupt |
| Pin 18 | RB1 — Port B bit 1 |
| Pin 19 | RB2 — Port B bit 2 |
| Pin 20 | RB3 — Port B bit 3 |
| Pin 21 | RB4 — Port B bit 4 |
| Pin 22 | RB5 — Port B bit 5 |
| Pin 23 | RB6 — Port B bit 6 |
| Pin 24 | RB7 — Port B bit 7 |
| Pin 25 | RA0/AN0 — Port A bit 0 / analog input 0 |
| Pin 26 | RA1/AN1 — Port A bit 1 / analog input 1 |
| Pin 27 | MCLR/VPP — Master clear reset / programming voltage |
| Pin 28 | VDD — Positive supply voltage (second pin) |
Typical Applications
PIC16C642-20I/SP is suitable for 7 applications: Appliance Control (Washing Machines, Ovens), Security and Alarm Systems, HVAC Thermostats and Building Controls, Small Motor Control (DC and Stepper), Industrial Process Controllers, Automotive Body Electronics (Non-Safety), Consumer Electronics and Toys.
Appliance Control (Washing Machines, Ovens)
The PIC16C642-20I/SP is well-suited for major and small appliance control boards where deterministic real-time response and a 5V supply are standard. Its 200 ns instruction cycle supports fast sensor polling (water level, temperature, door-switch interlocks) and PWM generation for motor or heater control. The two integrated analog comparators replace external op-amp stages for threshold detection (over-temperature, water level), reducing BOM cost and PCB area. Twenty-two high-current I/O pins can directly sink LEDs, relays, and triac gates without driver buffers. The industrial -40C to +85C rating handles under-cabinet, garage, or unheated utility-room environments. In a washing machine, this MCU typically handles the user-interface keypad and 7-segment display, motor-direction relay logic, water-valve solenoids, and the safety interlock chain. According to Microchip appliance reference designs, the PIC16C6xx family remains popular for cost-sensitive white-goods production.
Recommended
Security and Alarm Systems
The PIC16C642-20I/SP fits PIR-motion detector, door/window contact, and keypad-alarm panel designs where low cost, low power, and reliable operation are mandatory. Its Sleep-mode current and Watchdog Timer with dedicated RC oscillator let the part wake on external interrupts (sensor trigger) and recover automatically from firmware lockups. The 22 I/O pins accommodate multiple zone inputs, a piezo buzzer driver, an LED indicator array, and a relay-output for sirens. The two analog comparators can directly interface with PIR analog front-ends or thermocouple-amplified smoke-detector signals without extra op-amps. Industrial temperature tolerance ensures operation in attics, basements, and outdoor junction boxes. In commercial burglar-alarm panels, this MCU commonly drives the keypad-scanning matrix, manages the dialer handshake sequence, and supervises backup-battery charging through on-chip timer PWM.
Recommended
HVAC Thermostats and Building Controls
The PIC16C642-20I/SP is widely used in residential and light-commercial thermostats where it reads NTC thermistor inputs through its analog comparators, drives a multi-digit LCD or LED display, and switches HVAC contactors via opto-isolated triac drivers. Its 200 ns cycle time is fast enough for PI temperature-control loops at sub-second update rates, and the Watchdog Timer prevents firmware lockups that could leave HVAC equipment running indefinitely. Industrial temperature grade is essential because thermostats are mounted on interior walls subject to attic heat and exterior-wall cold-soak conditions. With 22 I/O, the MCU supports 7-day programmable scheduling, multi-stage heat/cool outputs, humidifier control, and a remote temperature-sensor input. In zoning panels, the same chip drives damper-motor relays and reads duct-temperature sensors.
Recommended
Small Motor Control (DC and Stepper)
The PIC16C642-20I/SP is a cost-effective controller for small brushed DC, unipolar stepper, and BLDC motors in appliances, vending machines, and small-format industrial equipment. Its 200 ns instruction cycle enables high-resolution PWM for torque-ripple smoothing, and 22 I/O pins drive full H-bridge gate signals, end-of-travel limit-switch inputs, and encoder-feedback channels without external logic. The two analog comparators sense back-EMF in sensorless BLDC applications or monitor motor current through a shunt resistor for stall detection. Industrial temperature range supports factory-floor and outdoor-pump environments. In a vending-machine dispenser, the MCU indexes the spiral coil, validates vend-completion sensors, and interlocks with the payment terminal. Reference Microchip application note AN898 for PIC-based stepper-drive firmware.
Recommended
Industrial Process Controllers
The PIC16C642-20I/SP serves low-channel-count industrial controllers such as tank-level monitors, batching controllers, and small-PLC replacement modules. Its industrial temperature rating and Watchdog Timer suit unattended factory-floor deployment, while the integrated analog comparators read 4-20 mA loop signals or thermocouple-amplified inputs directly. Twenty-two I/O handle solenoid outputs, contactor coils, HMI pushbutton inputs, and indicator LEDs. With 7KB OTP, it accommodates modest ladder-logic replacement programs. In a chemical-batching skid, the MCU can control peristaltic-pump dosing cycles and interlock with safety light curtains. Microchip recommends this part for cost-sensitive industrial nodes that don't require CAN or Ethernet connectivity, where a larger PIC18 or dsPIC would be overkill.
Recommended
Automotive Body Electronics (Non-Safety)
The PIC16C642-20I/SP (industrial -40C to +85C) is used in non-safety automotive body modules such as interior lighting controllers, mirror-adjust modules, seat-position memories, and accessory timers. While not AEC-Q100 qualified, the industrial temp grade handles passenger-compartment thermal loads. The 7KB OTP holds body-control firmware and the 22 I/O drive multiple lamp outputs (often through MOSFET drivers), read switch inputs, and generate PWM for mirror or seat motors. The two analog comparators can monitor current-sensing shunts for short-circuit detection. Automotive design houses use this part for low-end trim-line applications where the cost of an AEC-Q100 MCU is not justified. The PIC16C642-20E/SP variant (extended -40C to +125C) is preferred for underhood or door-module locations.
Recommended
Consumer Electronics and Toys
The PIC16C642-20I/SP is a workhorse for mid-complexity consumer products such as electronic learning aids, exercise equipment consoles, kitchen timers, and feature-rich battery-operated toys. Its 4-5.5V supply range matches 4xAA battery packs with a boost or direct 5V regulator, and the Sleep mode extends battery life in intermittently-used products. Twenty-two I/O support keypad scanning, LCD or LED matrix displays, audio-buzzer PWM, and motor-driver interfaces. With 7KB OTP, it can hold game logic, multi-language prompts, and motor-pattern sequences. Industrial temperature tolerance protects against temperature swings in shipping containers and outdoor use. In a stationary exercise bike, the MCU reads cadence sensors, drives the magnetic-brake PWM, and updates the LCD console - a complete implementation on a single chip.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C642-20I/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C642-20/SP | PIC16C642-20E/SP | PIC16C642-04I/SP | PIC16C642-04/SO | PIC16C642-04E/SP |
|---|---|---|---|---|---|---|
| Package | 28-SPDIP (0.300 inch) | 28-SPDIP - same | 28-SPDIP - same | 28-SPDIP - same | SOIC-28 - surface mount (different footprint) | 28-SPDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 4 MHz | 4 MHz | 4 MHz |
| Operating Temperature | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +125C (Extended) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +125C (Extended) |
| Program Memory | 7KB (4K x 14) OTP | 7KB OTP | 7KB OTP | 7KB OTP | 7KB OTP | 7KB OTP |
| RAM | 176 bytes | 176 bytes | 176 bytes | 176 bytes | 176 bytes | 176 bytes |
| I/O Pins | 22 | 22 | 22 | 22 | 22 | 22 |
| Supply Voltage | 4.0V to 5.5V | 4.0V to 5.5V | 4.0V to 5.5V | 4.0V to 5.5V | 4.0V to 5.5V | 4.0V to 5.5V |
| Mounting Type | Through-Hole (SPDIP) | Through-Hole | Through-Hole | Through-Hole | Surface Mount (SOIC) | Through-Hole |
Key Differentiators
- Industrial temperature grade with 20 MHz performance (vs PIC16C642-04I/SP)
- Two on-chip analog comparators reduce BOM cost (vs PIC16C642-20/SP)
- Wider industrial temperature range than commercial (vs PIC16C642-20/SP)
- Through-hole SPDIP for hand-prototyping ease (vs PIC16C642-04/SO)
Design Notes
Decouple VDD (pins 5 and 28) with a 100 nF ceramic capacitor placed within 5 mm of each VDD pin, and bulk-decouple with a 10 uF tantalum or aluminum polymer capacitor near the MCU. The PIC16C642 draws brief high-current spikes during internal EPROM programming; inadequate decoupling causes spurious resets. Place a 10 kohm pull-up on MCLR (pin 27) to VDD for normal operation - leave it floating only during EPROM programming.
Keep the 20 MHz crystal or resonator (between pins 7 and 8) within 10 mm of the MCU with short traces and a grounded guard ring to minimize EMI. Place OSC1/OSC2 traces on the same layer with no vias. For HC-49 style through-hole crystals, add a 1 Mohm parallel bias resistor across the crystal to stabilize oscillation across temperature. Avoid routing digital I/O traces parallel to and close to the crystal traces.
OTP EPROM cannot be reprogrammed - engineering samples must use a JW (windowed) package or a socketed SPDIP. For prototype code iteration, order PIC16C642-20I/JW (ceramic windowed CERDIP) and erase under UV light. Also note that VPP (programming voltage) is applied to MCLR (pin 27); ensure your in-circuit programming header does not share MCLR with a strong pull-down that prevents VPP rise.
The Watchdog Timer (WDT) uses a separate on-chip RC oscillator and runs even in Sleep mode. Clear WDT regularly in long-running loops - a stuck loop without WDT clear triggers a reset after ~18 ms (typical). For battery-backed Sleep-mode designs, the WDT-driven wakeup interval determines average current draw. Configure the OPTION_REG PSA bit to scale the WDT period if 18 ms is too short.
Estimated: at 20 MHz and 5V supply, the PIC16C642 draws approximately 15-20 mA active (per Microchip datasheet DC characteristics), dissipating 75-100 mW. Junction temperature rise in the 28-SPDIP package is minimal (<5 C above ambient) since thermal resistance is approximately 70 C/W and only modest copper area is required. No special thermal management is needed for typical consumer/industrial environments.
Compliance Information
Industrial-grade 8-bit MCU; not AEC-Q100 qualified for automotive safety applications. For automotive body modules, Microchip recommends PIC16F or PIC18 AEC-Q100 parts. RoHS/REACH compliance status not present in verified web data - check Microchip product page for current declarations.
