PIC16C642-20I/SO - 8-Bit 20MHz OTP MCU 7KB | Microchip
MPN: PIC16C642-20I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.78 | $27.80 |
| 100 | $2.62 | $262.00 |
| 500 | $2.45 | $1,225.00 |
| 1,000 | $2.3 | $2,300.00 |
PIC16C642-20I/SO Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, memory, and peripherals; the PIC16C642 specifically belongs to the mid-range PIC16C family that combines Harvard architecture (separate program and data buses) with a RISC instruction set for predictable real-time performance. In the broader semiconductor hierarchy it sits within microcontrollers -> microprocessors -> ICs -> semiconductors.
Key features include 22 I/O ports, three hardware timers, an analog comparator, programmable brown-out reset, and a programmable code-protection scheme that locks firmware after programming. The OTP program memory supports one-time programming via Microchip device programmers such as MPLAB PM3 or PICSTART Plus, making it well suited for production runs where firmware is final. Internal oscillator options are not available on this part - it requires an external clock source up to 20 MHz.
The device is built on a CMOS process with low-power consumption, supporting SLEEP mode with wake-up via interrupt or watchdog timer. Core peripherals include an 8-bit timer/counter (TMR0), Timer1 with capture/compare, and Timer2 for PWM generation. The analog comparator can be configured to interrupt the CPU on signal transitions. Five interrupt sources feed a single vector interrupt controller.
Typical applications include industrial control subsystems, automotive body electronics, appliance controllers, sensor interface boards, and consumer device firmware. The PIC16C642-20I/SO suits legacy designs, prototypes, and low-cost product runs where the 7KB OTP capacity and 22 I/O lines match the application envelope.
When designing with this part, remember OTP memory cannot be reprogrammed - once programmed the firmware is fixed. Use a windowed or flash-based PIC16 variant during development and convert to OTP for production. A 100 nF decoupling capacitor close to VDD and proper ground-plane layout reduce EMI on the 20 MHz clock line.
This page synthesizes distributor pricing (DigiKey, Mouser, LCSC, Octopart), Microchip cross-reference data, and engineering application notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C642-20I/SO — 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/SO (same form factor and footprint) — differing in Operating Temperature, Package, Program Memory Type, Instruction Cycle, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C642T-20I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C642-20/SO
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC16C642-04I/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$4.07 / Unit
View Datasheet →PIC16C642-04/SO
✅ Drop-In✓ In Stock
$4.3 / Unit
View Datasheet →PIC16C63-20I/SO
✅ Drop-In✓ In Stock
$6.5 / Unit
View Datasheet →PIC16C63-10/SO
✅ Drop-In✓ In Stock
$7.1 / Unit
View Datasheet →PIC16C63-04I/SP
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC16C642-20I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit RISC (Harvard) |
| Family | PIC16C |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 176 bytes |
| Maximum Clock Speed | 20 MHz |
| Instruction Cycle | 200 ns (single cycle) |
| Number of Instructions | 35 |
| Supply Voltage (VDD) | 4.0 V to 5.5 V |
| Number of I/O Pins | 22 |
| Timers | TMR0 (8-bit), Timer1 (16-bit), Timer2 (8-bit) |
| Analog Comparator | Yes (internal) |
| Brown-out Reset (BOR) | Yes (programmable) |
| Watchdog Timer | Yes (with dedicated RC oscillator) |
| Interrupt Sources | 5 |
| Package | 28-SOIC (7.50 mm width) |
| Operating Temperature | -40 C to +85 C (industrial) |
| Mounting Type | Surface Mount |
PIC16C642-20I/SO Pin Configuration
| Pin 1 | RA2 — PORTA bit 2 (digital I/O) |
| Pin 2 | RA3 — PORTA bit 3 (digital I/O) |
| Pin 3 | RA4 — PORTA bit 4 (digital I/O / T0CKI clock input) |
| Pin 4 | RA5 — PORTA bit 5 (digital I/O / SS-bar) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — PORTB bit 0 (interrupt-on-change) |
| Pin 7 | RB1 — PORTB bit 1 (interrupt-on-change) |
| Pin 8 | RB2 — PORTB bit 2 (interrupt-on-change) |
| Pin 9 | RB3 — PORTB bit 3 (interrupt-on-change / PGM low-voltage programming) |
| Pin 10 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 11 | RB5 — PORTB bit 5 (interrupt-on-change) |
| Pin 12 | RB6 — PORTB bit 6 (interrupt-on-change / ICSPCLK) |
| Pin 13 | RB7 — PORTB bit 7 (interrupt-on-change / ICSPDAT) |
| Pin 14 | VDD — Positive supply voltage (+5V) |
| Pin 15 | OSC2/CLKOUT — Oscillator crystal output / clock-out |
| Pin 16 | OSC1/CLKIN — Oscillator crystal input / external clock in |
| Pin 17 | RA0 — PORTA bit 0 (digital I/O) |
| Pin 18 | RA1 — PORTA bit 1 (digital I/O) |
| Pin 19 | VSS — Ground reference (secondary) |
| Pin 20 | VDD — Positive supply voltage (secondary) |
| Pin 21 | RC0 — PORTC bit 0 (digital I/O / T1OSO Timer1 osc output) |
| Pin 22 | RC1 — PORTC bit 1 (digital I/O / T1OSI Timer1 osc input) |
| Pin 23 | RC2 — PORTC bit 2 (digital I/O / CCP1) |
| Pin 24 | RC3 — PORTC bit 3 (digital I/O) |
| Pin 25 | RC4 — PORTC bit 4 (digital I/O) |
| Pin 26 | RC5 — PORTC bit 5 (digital I/O) |
| Pin 27 | RC6 — PORTC bit 6 (digital I/O) |
| Pin 28 | RC7 — PORTC bit 7 (digital I/O) |
Typical Applications
PIC16C642-20I/SO is suitable for 6 applications: Industrial Control Subsystems, Appliance Control Boards, Sensor Interface Boards, Automotive Body Electronics, Consumer Device Firmware, Legacy Embedded Replacement Boards.
Industrial Control Subsystems
The PIC16C642-20I/SO fits industrial control subsystems such as relay drivers, motor-control feedback boards, and PLC expansion modules. Its 22 I/O lines handle multi-channel digital I/O - input from limit switches and output to solenoid coils - while the 7 KB OTP memory stores fixed ladder-logic-equivalent firmware. The 20 MHz clock supports 200 ns deterministic response times critical for closed-loop control loops. Industrial -40C to +85C operation withstands factory-floor temperature swings, and the brown-out-reset circuit ensures reliable startup after power dips common in 24 V industrial rails stepped down to 5 V via DC-DC converters.
Recommended
Appliance Control Boards
The PIC16C642-20I/SO serves as the main controller in white goods and small appliances such as coffee machines, washing-machine control panels, and microwave oven interfaces. Its 22 I/O drives seven-segment displays, keypad matrices, and relay outputs, while the 7 KB OTP holds the appliance's fixed firmware. Low SLEEP-mode current extends battery life in clock-and-display appliances. The industrial temperature range tolerates the warm internal enclosure environment typical behind an appliance control panel. Microchip's MPLAB development tools and PIC16C family reference designs shorten firmware development for these cost-sensitive consumer applications.
Recommended
Sensor Interface Boards
The PIC16C642-20I/SO provides the timing-critical I/O handling for sensor interface boards in HVAC, building automation, and instrumentation. Its 22 digital I/O scan multiple digital sensors (PIR, reed switches, hall-effect sensors) while the on-chip analog comparator detects threshold crossings without external op-amps. The 20 MHz core processes up to 5 MIPS, sufficient for 1 kHz sensor polling with interrupt-driven service routines. Industrial -40C to +85C operation supports outdoor enclosures. OTP memory locks calibration coefficients to prevent field tampering, an advantage in metering and security sensor applications where firmware integrity is critical.
Recommended
Automotive Body Electronics
The PIC16C642-20I/SO handles non-safety body-electronics functions in legacy automotive designs such as interior lighting controllers, seat-position memory, and window-lift modules. Its 22 I/O connect directly to automotive-grade relay drivers, while the 7 KB OTP holds fixed production firmware. The -40C to +85C industrial temperature range covers cabin environments but is NOT rated for under-hood applications - use PIC16C642-04E/SO (extended -40C to +125C) for engine-bay electronics. Brown-out-reset handles automotive load-dump transients, and the watchdog timer recovers from firmware lockup due to EMC events.
Recommended
Consumer Device Firmware
The PIC16C642-20I/SO powers consumer-electronics sub-controllers in toys, remote controls, and small home appliances where its 7 KB OTP holds fixed feature sets and the 22 I/O drive LEDs, buttons, and audio tone generators. Its low-cost CMOS implementation keeps BOM cost below USD 3 per node, critical for high-volume consumer SKUs. The 20 MHz MIPS rating handles audio-tone synthesis, IR-protocol decoding (RC5/RC6/SIRC), and LED-matrix refresh without external timing chips. Microchip's MPLAB X IDE and XC8 compiler provide a free toolchain for these cost-sensitive designs.
Recommended
Legacy Embedded Replacement Boards
The PIC16C642-20I/SO is commonly specified as the form-fit-function replacement in legacy embedded systems originally designed around PIC16C6x family controllers. Its 28-SOIC footprint matches the original PIC16C61/62/63/64/65/71 layout, allowing PCB re-spin avoidance in field-repair and factory-replacement applications. The OTP memory locks in the legacy firmware version, preventing unauthorized field updates. The industrial -40C to +85C rating supports long-life industrial systems. Active production as of 2026-09-17 means replacement boards remain available for the installed base of industrial and medical equipment using this controller.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C642-20I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C642T-20I/SO | PIC16C642-20/SO | PIC16C642-04I/SO | PIC16C63-20I/SO | PIC16C63-10/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC |
| Maximum Clock Speed | 20 MHz | 20 MHz | 20 MHz | 4 MHz | 20 MHz | 10 MHz |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP |
| RAM Size | 176 bytes | 176 bytes | 176 bytes | 176 bytes | 368 bytes | 368 bytes |
| Number of I/O | 22 | 22 | 22 | 22 | 22 | 22 |
| Supply Voltage | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | 0C to +70C (Commercial) | -40C to +85C | -40C to +85C | 0C to +70C |
| Hardware USART | No | No | No | No | Yes | Yes |
Key Differentiators
- Industrial temperature grade with -40C to +85C range (vs PIC16C642-20/SO)
- Doubles RAM and adds hardware USART versus PIC16C642 family base (vs PIC16C63-20I/SO)
- Same 20 MHz performance as -20 variants (vs PIC16C63-10/SO)
Design Notes
The PIC16C642-20I/SO requires a stable 4.0 V to 5.5 V VDD supply with a decoupling capacitor of 100 nF placed as close as physically possible to the VDD pins (14 and 20) and VSS pins (5 and 19). For noisy industrial environments, add a 10 uF bulk capacitor at the regulator output. The internal brown-out-reset circuit triggers at approximately 4.0 V; ensure the regulator rise time is faster than 50 ms to avoid multiple BOR events during power-up. Estimated: with a 22 I/O lines all sourcing 20 mA, peak VDD current is 440 mA - select a regulator rated for at least 500 mA.
Keep the oscillator traces (OSC1/CLKIN pin 16, OSC2/CLKOUT pin 15) as short as possible - under 10 mm - and surround them with a ground guard ring. Place the crystal or resonator within 5 mm of the MCU. For HS-mode crystals above 8 MHz, add a 1 M-ohm parallel bias resistor across OSC1/OSC2 to prevent startup issues. Route the ICSP programming signals (RB6/RB7) with 0.1-inch spacing so a 5-pin header can be installed in production for in-circuit programming.
OTP memory cannot be erased - the PIC16C642-20I/SO is a one-time-programmable device and a single bit error in the firmware image bricks the chip. Use a PIC16C642-20E/SO windowed CERDIP variant or a flash-based PIC16F628-20I/SO for development, then qualify the OTP version only after the firmware image has passed full validation. Estimated: programming time for a 7 KB image at 5 V supply is approximately 1 second per device using the MPLAB PM3 programmer.
Compliance Information
RoHS compliant per Microchip product page; matte-tin lead-free finish. Not AEC-Q100 qualified - choose PIC16C642-04E/SO for automotive applications.
