PIC16C642T-04/SO - 8-Bit 4MHz OTP MCU 7KB Flash 28-SOIC | Microchip
MPN: PIC16C642T-04/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.5 | $6.50 |
| 10 | $5.95 | $59.50 |
| 100 | $5.2 | $520.00 |
| 500 | $4.6 | $2,300.00 |
| 1,000 | $4.1 | $4,100.00 |
PIC16C642T-04/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, RAM, and peripherals on one die. Within the broader taxonomy, an MCU is a type of microprocessor (MPU) -> central processing unit (CPU) -> semiconductor -> integrated circuit. The PIC16C family uses Microchip's classic Harvard RISC architecture with separate program and data buses, optimized for deterministic interrupt response and low-cost embedded control. PIC microcontrollers sit alongside AVR (Microchip/Atmel), STM8 (ST), and 8051 (Intel heritage) in the 8-bit MCU segment, where they power cost-sensitive consumer, industrial, and automotive subsystems.
The PIC16C642 includes key features that distinguish it for embedded control: 22 digital I/O pins, brown-out reset (peripherals listed as Brown-out in the verified data), an external oscillator interface (no internal oscillator), 176 bytes of data RAM, and OTP program memory that allows programming once with EPROM-style cells. Operating supply voltage is 4V to 6V (commercial 5V typical). The 28-SOIC wide-body package (0.295" / 7.50 mm) provides robust solder joints for hand-rework and through-hole-style PCB pad geometry.
Typical applications include industrial control logic, sensor signal conditioning front-ends, simple human-machine interface (HMI) boards, appliance controllers, and legacy replacement designs. The 22 I/O count and 4 MHz CPU are sufficient for bit-banged communication protocols, keypad scanning, and relay/LED driving.
A critical design consideration is OTP memory: code cannot be re-flashed. For development, choose a windowed (JW) or Flash-based PIC16F equivalent. The external oscillator also requires an external crystal or resonator - plan PCB layout for crystal placement near the OSC1/OSC2 pins.
Drop-in alternatives for PIC16C642T-04/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-04/SO (same form factor and footprint) — differing in Program Memory Type, Core Architecture, Package, Program Memory Size, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C642-04/SO
✅ Drop-In✓ In Stock
$4.3 / Unit
View Datasheet →PIC16C642-04E/SO
✅ Drop-In✓ In Stock
$3.62 / 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 →PIC16C642-04E/SP
✅ Drop-In✓ In Stock
$5.65 / Unit
View Datasheet →PIC16C642T-04/SO Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-Bit |
| Core Architecture | PIC16 (Harvard RISC) |
| Max Clock Speed | 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 176 x 8 bytes |
| EEPROM Size | Not specified |
| Number of I/O Pins | 22 |
| Supply Voltage (Vcc/Vdd) | 4 V to 6 V |
| Oscillator Type | External |
| Peripherals | Brown-out Detect/Reset |
| Data Converters | Not specified |
| Connectivity | Not specified |
| Package | 28-SOIC (0.295", 7.50 mm width) |
| Mounting Type | Surface Mount |
| Supplier Device Package | 28-SOIC |
| Operating Temperature Grade | Commercial |
| Terminal Form | GULL WING |
PIC16C642T-04/SO Pin Configuration
| Pin 1 | RA2/AN2 — Bidirectional I/O / analog input |
| Pin 2 | RA3/AN3 — Bidirectional I/O / analog input |
| Pin 3 | RA4/T0CKI — Bidirectional I/O / Timer0 clock input |
| Pin 4 | RA5/SS/AN4 — Bidirectional I/O / SPI slave select |
| Pin 5 | RB0/INT — Bidirectional I/O / external interrupt |
| Pin 6 | RB1 — Bidirectional I/O |
| Pin 7 | RB2 — Bidirectional I/O |
| Pin 8 | Vss — Ground reference |
| Pin 9 | OSC1/CLKIN — External oscillator input |
| Pin 10 | OSC2/CLKOUT — External oscillator output |
| Pin 11 | RC0/T1OSO/T1CKI — Bidirectional I/O / Timer1 |
| Pin 12 | RC1/T1OSI/CCP2 — Bidirectional I/O / Capture/Compare/PWM |
| Pin 13 | RC2/CCP1 — Bidirectional I/O / Capture/Compare/PWM |
| Pin 14 | RC3/SCK/SCL — Bidirectional I/O / SPI/I2C clock |
| Pin 15 | RC4/SDI/SDA — Bidirectional I/O / SPI data in / I2C data |
| Pin 16 | RC5/SDO — Bidirectional I/O / SPI data out |
| Pin 17 | RC6/TX/CK — Bidirectional I/O / UART TX |
| Pin 18 | RC7/RX/DT — Bidirectional I/O / UART RX |
| Pin 19 | Vss — Ground reference |
| Pin 20 | VDD — Positive supply (4V-6V) |
| Pin 21 | RB3 — Bidirectional I/O |
| Pin 22 | RB4 — Bidirectional I/O |
| Pin 23 | RB5 — Bidirectional I/O |
| Pin 24 | RB6/PGC — Bidirectional I/O / ICSP clock |
| Pin 25 | RB7/PGD — Bidirectional I/O / ICSP data |
| Pin 26 | RA0/AN0 — Bidirectional I/O / analog input |
| Pin 27 | RA1/AN1 — Bidirectional I/O / analog input |
| Pin 28 | MCLR/VPP — Master clear reset / programming voltage |
Typical Applications
PIC16C642T-04/SO is suitable for 6 applications: Industrial Control Logic, Sensor Signal Conditioning Front-End, Appliance Control Board, HMI Keypad/LED Driver Board, Legacy Replacement / Industrial Embedded Maintenance, Simple Communication Gateway.
Industrial Control Logic
The PIC16C642T-04/SO is well suited for industrial control logic boards where deterministic 8-bit performance and 22 I/O pins drive relays, optocouplers, and discrete sensors. Its 4 MHz core and Harvard RISC architecture deliver one instruction per clock cycle (1 MIPS), enabling fast response to interrupts for safety-critical interlocks. The 7 KB OTP program memory holds mid-sized ladder-logic replacement firmware, and the brown-out reset peripheral protects against supply droop in 24V industrial backplanes stepped down to 5 V. Wide-body 28-SOIC packaging tolerates hand-rework common in field-deployed industrial panels.
Recommended
Sensor Signal Conditioning Front-End
The PIC16C642T-04/SO can host a low-cost sensor signal-conditioning front-end, multiplexing analog inputs through an external ADC and providing digital filtering plus linearization. With 22 I/O pins, the MCU can scan multiple sensor channels (temperature, pressure, humidity) and output a clean conditioned signal over UART or PWM. The 4 MHz clock is sufficient for 100 Hz sample rates on 4-6 channels. Brown-out detection prevents false sensor readings during supply transients in field installations.
Recommended
Appliance Control Board
The PIC16C642T-04/SO targets white-goods and appliance control boards (washing machines, dishwashers, microwave ovens) where 8-bit PIC is the industry standard. The 22 I/O pins handle keypads, LED indicators, triac-fired heaters, and motor-direction relays, while the 7 KB OTP stores state-machine firmware for wash/dry cycles. The wide 4-6 V supply range tolerates rectified 5 V rails common in appliances. OTP memory prevents firmware tampering in warranty-sensitive consumer products.
Recommended
HMI Keypad/LED Driver Board
The PIC16C642T-04/SO excels as an HMI keypad-scanning and LED-multiplexing controller, leveraging its 22 I/O to drive a 4x4 matrix keypad and a 7-segment LED display via charlieplexing. The 4 MHz core runs a 10 Hz scan rate with debounce, eliminating the need for an external keypad controller. Brown-out reset keeps the display blank during supply brown-outs, preventing garbled output. Surface-mount 28-SOIC enables compact front-panel PCBs.
Recommended
Legacy Replacement / Industrial Embedded Maintenance
The PIC16C642T-04/SO is targeted at maintaining legacy industrial equipment originally designed in the 1990s-2000s, where OTP PIC16C parts are already qualified and PCB footprints are fixed. With identical pinout to the original, it serves as a direct authorized replacement when the installed MCU has failed. The 28-SOIC wide-body package matches the original PCB pad pattern, requiring no board rework. Engineers should lot-track and date-code verify for long-term spare-part stocking.
Recommended
Simple Communication Gateway
The PIC16C642T-04/SO can act as a low-cost serial-to-parallel or UART-to-SPI bridge, using its 22 I/O to emulate simple protocol converters for legacy equipment. At 4 MHz it sustains 9600-19200 baud UART traffic with minimal CPU overhead, while bit-banging SPI or I2C master transactions to peripheral chips. The OTP memory holds the bridge protocol stack once, and brown-out reset protects the gateway from corrupting downstream devices during power events.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C642T-04/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C642-04/SO | PIC16C642-04E/SO | PIC16C642-04I/SO | PIC16C642-04E/SP |
|---|---|---|---|---|---|
| Package | 28-SOIC (0.295", 7.50 mm) | 28-SOIC (0.295", 7.50 mm) - same | 28-SOIC (0.295", 7.50 mm) - same | 28-SOIC (0.295", 7.50 mm) - same | 28-SPDIP (0.300") - through-hole |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Program Memory | 7 KB (4K x 14) OTP | 7 KB (4K x 14) OTP - identical | 7 KB (4K x 14) OTP - identical | 7 KB (4K x 14) OTP - identical | 7 KB (4K x 14) OTP - identical |
| RAM Size | 176 bytes | 176 bytes - identical | 176 bytes - identical | 176 bytes - identical | 176 bytes - identical |
| Max Clock Speed | 4 MHz | 4 MHz - identical | 4 MHz - identical | 4 MHz - identical | 4 MHz - identical |
| Number of I/O | 22 | 22 - identical | 22 - identical | 22 - identical | 22 - identical |
| Temperature Grade | Commercial | Commercial - same | Extended | Industrial (-40C to +85C) | Extended |
| Packaging Format | Tape & Reel | Tube | Tube | Tube | Tube (SP = SPDIP) |
Key Differentiators
- Wide-body SOIC for hand-reworkability (vs PIC16F18425-I/SL)
- Identical silicon as tube-delivery sibling (vs PIC16C642-04/SO)
- OTP memory prevents firmware tampering (vs Flash-based PIC16F628A)
Design Notes
The PIC16C642T-04/SO uses One-Time Programmable (OTP) EPROM memory - the program memory can be written exactly once and CANNOT be erased or re-flashed. Engineers prototyping firmware must use a windowed (UV-erasable) PIC16C642/JW sample for development, or migrate to the Flash-based PIC16F628A-I/SO equivalent which supports in-circuit serial programming (ICSP) and many erase/write cycles. Failing to plan ahead results in scrapped production chips.
Place the external crystal or ceramic resonator within 5 mm of the OSC1 (pin 9) and OSC2 (pin 10) pins, with the load capacitors (typically 15-33 pF) returned to a clean analog-style ground pour separated from noisy digital grounds. Keep oscillator traces short and surround them with a ground guard ring to prevent injection of switching noise from relay drivers or triac circuits on the same board. This is critical for the PIC16C642 because it has no internal oscillator.
The PIC16C642 operates from 4 V to 6 V (5 V typical). Add a 100 nF decoupling capacitor as close as possible to the VDD pin (pin 20), with a second bulk 10 uF tantalum or ceramic capacitor on the 5 V rail near the IC. The brown-out reset peripheral can be configured via CONFIG register to assert MCLR if VDD drops below ~4.0 V - configure this in code for reliable industrial operation. Verify the upstream regulator provides clean 5 V under relay inrush conditions.
The PIC16C642T-04/SO in 28-SOIC has a thermal resistance (theta_JA) of approximately 80 C/W. At typical embedded-control current draws of 5-15 mA from a 5 V supply, self-heating is negligible (<5 mW). However, when placed in a sealed enclosure with no airflow alongside other heat-generating components, ambient temperature can rise; verify the commercial-grade -40C to +85C operating range is sufficient for the enclosure's worst-case internal temperature.
Compliance Information
RoHS status not provided in verified web data. PIC16C family predates widespread automotive AEC-Q100 qualification requirements; the PIC16C642 is commercial/industrial grade only. Conflict minerals compliance assumed per Microchip corporate policy but specific declarations not in the verified data.