PIC16C642T-20E/SO - 8-Bit 20MHz OTP MCU 7KB | Microchip
MPN: PIC16C642T-20E/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.85 | $5.85 |
| 10 | $5.27 | $52.70 |
| 100 | $4.68 | $468.00 |
| 500 | $4.2 | $2,100.00 |
| 1,000 | $3.75 | $3,750.00 |
PIC16C642T-20E/SO Overview
A microcontroller (MCU) is a single-chip integrated circuit that combines a CPU core, non-volatile program memory, working RAM, and a configurable set of peripheral modules. Within the broader semiconductor hierarchy, an MCU belongs to the class of programmable logic devices and is itself a subclass of microcomputers designed for embedded control. The PIC16C family is the mid-tier of Microchip's original PIC16C 8-bit portfolio, sitting between the PIC16C5x baseline and the PIC16C7x higher-performance parts.
The PIC16C642T-20E/SO integrates an enhanced capture/compare/PWM (ECCP) module, an 8-bit analog-to-digital converter (ADC) with up to 8 input channels, a USART for asynchronous serial communication, and a synchronous serial port that supports SPI and I2C master/slave operation. The device also offers programmable brown-out reset, power-on reset, and a watchdog timer with its own on-chip RC oscillator for enhanced system reliability. Its Harvard architecture separates program and data paths, enabling simultaneous fetch and write operations that yield predictable, deterministic execution timing.
Typical applications include industrial control and instrumentation, automotive body and chassis subsystems, smart sensor conditioning nodes, appliance controllers, and remote data acquisition nodes. Its small footprint, wide operating temperature range, and OTP programmability make it especially attractive for low-volume production runs where mask-ROM commitment is not economical.
When designing with this part, note that the OTP memory means firmware cannot be field-updated; verify code before programming. Use the in-circuit debugger header or ICD pins for development, and reserve decoupling on VDD/VSS within 1 cm of the package. The PIC16C642T-20E/SO is supplied in tape and reel packaging for high-volume surface-mount assembly.
This page synthesizes distributor pricing, drop-in alternatives from Microchip's PIC16C family and select competitors, and practical design notes that go beyond the manufacturer datasheet to accelerate design-in for engineers.
Drop-in alternatives for PIC16C642T-20E/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 PIC16C642T-20E/SO (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, Package, Maximum Clock Frequency, Instruction Cycle Time.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C642-20I/SO
✅ Drop-In✓ In Stock
$2.3 / Unit
View Datasheet →PIC16C642T-10/SO
✅ Drop-In✓ In Stock
$3.9 / 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 →PIC16C621A-20E/SS
✅ Drop-In✓ In Stock
$4.12 / Unit
View Datasheet →PIC16C642T-20E/SO Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-Bit |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7KB (4K x 14) |
| RAM Size | 176 x 8 bytes |
| Number of I/O | 22 |
| Operating Frequency | 20MHz |
| Instruction Cycle Time | 200ns |
| Supply Voltage (VDD) | 5V nominal |
| ADC | 8-bit, up to 8 channels |
| Communication Interfaces | USART, SPI, I2C (SSP) |
| Timers | Timer0, Timer1, Timer2 |
| Capture/Compare/PWM | ECCP module |
| Package | 28-SOIC (7.50mm width) |
| Operating Temperature Range | -40C to +125C (E suffix) |
| Mounting Type | Surface Mount |
| RoHS Status | Non-RoHS (OTP legacy family) |
| Packaging | Tape & Reel (T suffix) |
PIC16C642T-20E/SO Pin Configuration
| Pin 1 | RA2/AN2 — Bidirectional I/O; analog channel 2 |
| Pin 2 | RA3/AN3 — Bidirectional I/O; analog channel 3 |
| Pin 3 | RA4/T0CKI — Bidirectional I/O; Timer0 clock input |
| Pin 4 | RA5/AN4 — Bidirectional I/O; analog channel 4 |
| Pin 5 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 6 | OSC2/CLKOUT — Oscillator output |
| Pin 7 | RC0 — Bidirectional I/O |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RC1 — Bidirectional I/O |
| Pin 10 | RC2/CCP1 — Bidirectional I/O; ECCP channel 1 |
| Pin 11 | RC3 — Bidirectional I/O |
| Pin 12 | RC4 — Bidirectional I/O |
| Pin 13 | RC5 — Bidirectional I/O |
| Pin 14 | RC6 — Bidirectional I/O; USART TX/CK |
| Pin 15 | RC7 — Bidirectional I/O; USART RX/DT |
| Pin 16 | RB0/INT — Bidirectional I/O; external interrupt |
| Pin 17 | RB1 — Bidirectional I/O |
| Pin 18 | RB2 — Bidirectional I/O |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply (5V) |
| Pin 21 | RB3 — Bidirectional I/O |
| Pin 22 | RB4 — Bidirectional I/O; interrupt-on-change |
| Pin 23 | RB5 — Bidirectional I/O; interrupt-on-change |
| Pin 24 | RB6 — Bidirectional I/O; interrupt-on-change |
| Pin 25 | RB7 — Bidirectional I/O; interrupt-on-change |
| Pin 26 | RA0/AN0 — Bidirectional I/O; analog channel 0 |
| Pin 27 | RA1/AN1 — Bidirectional I/O; analog channel 1 |
| Pin 28 | MCLR/VPP — Reset input / programming voltage |
Typical Applications
PIC16C642T-20E/SO is suitable for 6 applications: Industrial Control Systems, Automotive Body Electronics, Smart Sensor Conditioning, Appliance Controllers, Remote Data Acquisition Nodes, Hobbyist and Educational Development.
Industrial Control Systems
The PIC16C642T-20E/SO fits industrial control designs requiring deterministic 8-bit processing in a small footprint. Its 20MHz core delivers 5 MIPS of throughput, sufficient for PID loops, sequencing logic, and HMI scanning at sub-millisecond cycle times. The 22 I/O lines interface directly to 5V logic levels common in factory-floor discrete I/O. The on-chip 8-bit ADC monitors up to 8 analog inputs such as temperature, pressure, or current feedback without an external converter. The USART links the MCU to operator panels or supervisory PLCs, while the SSP (SPI/I2C) connects to digital sensors or EEPROM. The -40C to +125C extended temperature grade allows deployment near motors or in unheated cabinets. Use ECCP PWM for driving contactors or solid-state relays with software dead-band control.
Recommended
Automotive Body Electronics
The PIC16C642T-20E/SO is well matched to 12V automotive body modules such as lighting controllers, seat modules, mirror adjusters, and HVAC damper drivers. Its -40C to +125C operating range covers under-hood and cabin extremes. The 5V regulator can be derived from the 12V bus via a simple LDO. ECCP PWM outputs drive LED strings, motors, or solenoids with hardware dead-band control. The 8-bit ADC reads thermistor or potentiometer inputs for analog feedback. Hardware brown-out reset and watchdog timer provide fault recovery required in automotive environments. The OTP memory secures firmware from unauthorized modification. Note that for new automotive designs, consider AEC-Q100 qualified PIC16F equivalents, as the PIC16C family is not AEC-Q100 certified.
Recommended
Smart Sensor Conditioning
The PIC16C642T-20E/SO operates as a smart front-end for analog sensors, integrating excitation, signal conditioning, linearization, and digital output in a single chip. The 8-bit ADC digitizes sensor voltages at up to 8 channels, while the USART transmits calibrated data to a host controller via RS-232/RS-485. The PIC16C core provides deterministic instruction timing so filter algorithms execute in fixed cycle counts. Programmable pull-ups and interrupt-on-change inputs eliminate external components for switch or quadrature encoder reading. The 28-SOIC package allows surface-mount assembly in compact sensor housings. Brown-out reset prevents erroneous readings during supply dips, and the watchdog timer recovers from software lock-ups in unattended field installations.
Recommended
Appliance Controllers
The PIC16C642T-20E/SO is a strong fit for white-goods controllers including washing machines, dishwashers, microwave ovens, and small kitchen appliances. Its 7KB OTP memory stores motor-control algorithms and user-interface state machines. The 22 I/O pins drive 7-segment displays, keypads, triac interfaces, and buzzer feedback. ECCP PWM with hardware dead-band manages universal motor phase control or inverter-fed BLDC drives at low cost. The SSP port interfaces to EEPROM for storing user presets and error logs. With -40C to +125C tolerance, the part survives the thermal cycling common inside appliance cabinets. OTP programming locks firmware into each unit for production, preventing field tampering.
Recommended
Remote Data Acquisition Nodes
The PIC16C642T-20E/SO can serve as the controller for remote data loggers, environmental monitors, and battery-powered telemetry endpoints. The PIC16C architecture's low-power sleep modes (with watchdog wakeup) extend battery life in unattended deployments. The 8-bit ADC samples analog channels periodically; ECCP can be repurposed as a timer for sample interval generation. USART connects to RS-485 transceivers or low-power radio modules. The SSP bus drives I2C temperature/humidity sensors or SPI flash for log storage. With only 7KB of code space, this MCU targets firmware that fits into a single loop with interrupt-driven sensor reads. Industrial temperature tolerance supports outdoor and cabinet-mounted installations.
Recommended
Hobbyist and Educational Development
The PIC16C642T-20E/SO is an authentic teaching vehicle for learning 8-bit embedded programming with the classic PIC16C architecture. The Harvard bus, accumulator-based ALU, and single-word instructions make the assembly language approachable for students. Its 20MHz execution, 7KB program memory, and rich peripheral set (USART, SSP, ECCP, ADC) cover the canonical embedded curriculum: GPIO, timers, interrupts, PWM, ADC, and serial protocols. The 28-SOIC package fits standard 0.1-inch pitch breakout boards for breadboarding. PIC16C devices are still used in university courses that emphasize OTP device programming flows. Hobbyists building retro-computing projects value the deterministic timing and visible assembly behavior.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C642T-20E/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C642-20I/SO | PIC16C642T-10/SO | PIC16C642-04/SO | PIC16C642-04E/SP | PIC16C621A-20E/SS |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC | 28-SPDIP (through-hole, pin-compatible) | 28-SSOP |
| Program Memory | 7KB (4K x 14) OTP | 7KB OTP | 7KB OTP | 7KB OTP | 7KB OTP | 1.75KB OTP |
| Max Clock Speed | 20MHz | 20MHz | 10MHz | 4MHz | 4MHz | 20MHz |
| Temperature Range | -40C to +125C (E) | -40C to +85C (I) | -40C to +85C | -40C to +85C | -40C to +125C (E) | -40C to +125C (E) |
| I/O Count | 22 | 22 | 22 | 22 | 22 | 13 |
| ADC | 8-bit, 8 channels | 8-bit, 8 channels | 8-bit, 8 channels | 8-bit, 8 channels | 8-bit, 8 channels | None |
| Packaging Format | Tape & Reel | Tube | Tape & Reel | Tube | Tube | Tube |
Key Differentiators
- Extended -40C to +125C temperature grade with tape-and-reel packaging (vs PIC16C642-20I/SO)
- Highest clock speed in the PIC16C642 family (vs PIC16C642T-10/SO)
- Full 7KB OTP memory with 22 I/O for higher pin count than PIC16C621A (vs PIC16C621A-20E/SS)
Design Notes
The PIC16C642T-20E/SO requires a stable 5V supply with a decoupling capacitor of at least 0.1uF placed within 1 cm of the VDD pin (pin 20). For noisy industrial environments, add a 10uF bulk capacitor at the supply rail. The VSS pins (8 and 19) should both be tied to a low-impedance ground plane. Brown-out reset must be enabled in configuration fuses to prevent code execution below the minimum operating voltage. Estimated: at 20MHz and 5V, the supply current is approximately 15-20 mA during active execution.
OTP memory is one-time programmable; once programmed, the firmware cannot be changed. Verify code thoroughly in a windowed or Flash-equivalent PIC16F part before committing to PIC16C642T-20E/SO production units. The MCLR/VPP pin (28) must not be left floating; tie to VDD through a 10k resistor or drive from a supervisor. Failure to do so may cause spurious resets. Configuration bits must be set correctly: oscillator selection, watchdog enable, brown-out enable, and code protection all affect operation. Use Microchip's MPLAB environment with PICkit 2/3 for programming.
The 28-SOIC footprint is 7.50mm wide, suitable for standard surface-mount assembly. Keep analog and digital grounds separated at the die, joining them only at the VSS pins of the MCU. Place the 20MHz crystal or resonator within 5mm of OSC1/OSC2 (pins 5/6) with short traces to minimize EMI and stray capacitance. If using an external clock, drive OSC1 with a CMOS-level source and leave OSC2 unconnected. The ADC channels (RA0-RA5) should be routed away from switching signals to prevent crosstalk. For high-current output pins, use 100-ohm series resistors near the MCU to limit ringing.
Compliance Information
PIC16C OTP family predates RoHS widespread adoption; parts typically have matte-tin finish but no formal RoHS certificate. Not AEC-Q100 qualified. The PIC16C642T-20E/SO is in NRND (Not Recommended for New Designs) status per Microchip's product lifecycle policy.
