PIC16C642-04E/SO - 8-Bit 4MHz 7KB OTP MCU 28-SOIC | Microchip
MPN: PIC16C642-04E/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.78 | $5.78 |
| 10 | $5.2 | $52.00 |
| 100 | $4.62 | $462.00 |
| 500 | $4.05 | $2,025.00 |
| 1,000 | $3.62 | $3,620.00 |
PIC16C642-04E/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, RAM, non-volatile program memory, and peripheral I/O on one die. The PIC16C642 belongs to the mid-range PICmicro MCU family, sitting within the broader 8-bit MCU taxonomy (8-bit MCU -> microcontroller -> embedded processor -> semiconductor). OTP variants are programmed once at production or in the field with a device programmer and cannot be erased, making them ideal for mature, fixed-function products with stable firmware. The 'C' in PIC16C642 indicates the OTP-programmable CMOS core, while the '642' places it in the 28-pin mid-range pinout family with capture/compare/PWM and an 8-bit A/D converter.
Key features of the PIC16C642-04E/SO include the 4MHz oscillator (the '-04' speed code), 7KB OTP program memory, 176 bytes of RAM, 22 I/O pins, a 200ns instruction cycle, integrated timer/counter modules, and an extended temperature grade of -40C to +125C (the '-E' suffix). The 28-SOIC package offers a 0.295" (7.50mm) body width and 1.27mm pitch, well-suited for hand-soldering and low-density production runs. The part is lead-free and RoHS-compliant per the Microchip product page.
The PIC16C642 uses a Harvard RISC architecture with separate program and data buses, an 8-bit ALU, and 14-bit instruction words for compact code. The 4MHz oscillator combined with a 4:1 internal divider gives the documented 1 MIPS (200ns instruction cycle) throughput. Power-saving features include SLEEP mode with wake-up on interrupt and a Watchdog Timer with an on-chip RC oscillator for reliable system recovery without external components.
Typical applications include appliance controllers, simple sensor readouts, automotive body modules, industrial timer/counter boards, LED driver sequencers, and consumer white-goods user interfaces. The extended temperature grade makes it suitable for under-hood automotive subsystems and outdoor industrial enclosures. The 22 I/O pins allow direct connection to keypads, seven-segment displays, low-cost LCDs, and serial EEPROMs for data logging.
When designing with this MCU, consider that OTP memory cannot be re-programmed, so a FLASH-based PIC16F equivalent (e.g., PIC16F648A) is recommended during prototyping. Adequate decoupling (100nF ceramic plus 10uF bulk) is required on VDD/AVDD pins, and unused I/O should be configured as outputs low to minimize power consumption in SLEEP mode. The ICSP programming interface uses RB6 (clock) and RB7 (data) and must be reserved for in-circuit programming access.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, giving embedded engineers a single reference for sourcing, substitution, and design-in of the PIC16C642-04E/SO.
Drop-in alternatives for PIC16C642-04E/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 PIC16C642-04E/SO (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, Core Architecture, Package, 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 →PIC16C642-10/SO
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C642-20/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$4.85 / Unit
View Datasheet →PIC16C642-04E/SP
✅ Drop-In✓ In Stock
$5.65 / Unit
View Datasheet →PIC16C642-04E/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Core Size | 8-bit |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 176 x 8 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle Time | 200 ns |
| Number of I/O Pins | 22 |
| Data Bus Width | 8-bit |
| Instruction Set Size | 35 single-word instructions |
| Package | 28-SOIC (0.295", 7.50mm body width) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40C to +125C (Extended, '-E' grade) |
| Lead-Free / RoHS | Yes / Compliant |
PIC16C642-04E/SO Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0 — Port A bit 0 (digital I/O) |
| Pin 3 | RA1 — Port A bit 1 (digital I/O) |
| Pin 4 | RA2 — Port A bit 2 (digital I/O) |
| Pin 5 | RA3 — Port A bit 3 (digital I/O) |
| Pin 6 | RA4 — Port A bit 4 (digital I/O, open-drain option) |
| Pin 7 | RA5 — Port A bit 5 (digital I/O) |
| Pin 8 | RE0 — Port E bit 0 (digital I/O) |
| Pin 9 | RE1 — Port E bit 1 (digital I/O) |
| Pin 10 | RE2 — Port E bit 2 (digital I/O) |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC1 — Oscillator input or external clock input |
| Pin 14 | OSC2 — Oscillator output |
| Pin 15 | RC0 — Port C bit 0 (digital I/O) |
| Pin 16 | RC1 — Port C bit 1 (digital I/O) |
| Pin 17 | RC2 — Port C bit 2 (digital I/O) |
| Pin 18 | RC3 — Port C bit 3 (digital I/O) |
| Pin 19 | RC4 — Port C bit 4 (digital I/O) |
| Pin 20 | RC5 — Port C bit 5 (digital I/O) |
| Pin 21 | RC6 — Port C bit 6 (digital I/O / TX) |
| Pin 22 | RC7 — Port C bit 7 (digital I/O / RX) |
| Pin 23 | RB0 — Port B bit 0 (digital I/O, interrupt-on-change) |
| Pin 24 | RB1 — Port B bit 1 (digital I/O, interrupt-on-change) |
| Pin 25 | RB2 — Port B bit 2 (digital I/O, interrupt-on-change) |
| Pin 26 | RB3 — Port B bit 3 (digital I/O, interrupt-on-change) |
| Pin 27 | RB4 — Port B bit 4 (digital I/O, interrupt-on-change) |
| Pin 28 | RB5 — Port B bit 5 (digital I/O, interrupt-on-change) |
Typical Applications
PIC16C642-04E/SO is suitable for 6 applications: White Goods and Appliance Control, Industrial Timer and Counter Modules, Automotive Body Electronics, Consumer Keypad and LED Sequencer, Simple Sensor Readout and Data Logger, Hobby and Educational Embedded Projects.
White Goods and Appliance Control
The PIC16C642-04E/SO fits white-goods and appliance controllers because its 22 I/O pins can directly drive seven-segment displays, keypads, relay coils, and triac interfaces without external logic. The 7KB OTP memory holds fixed function-control firmware (wash cycles, fan speeds, timer routines) and the 200ns instruction cycle responds to interrupts and timer events with deterministic latency, critical for safety interlocks. The extended -40C to +125C temperature grade tolerates the heat of motor compartments and continuous-duty operation. Place the MCU on a 28-SOIC footprint with 100nF/10uF decoupling on VDD and route MCLR to a 10k pull-up so the part survives inrush transients during appliance startup.
Recommended
Industrial Timer and Counter Modules
The PIC16C642-04E/SO is well matched to industrial timer/counter boards where it must run unattended for years in a 24V cabinet. Its on-chip Timer0/Timer1 modules provide accurate event counting and the Watchdog Timer with internal RC oscillator keeps the system alive in electrically noisy environments. The 4MHz oscillator plus 200ns instruction cycle yield reliable debounce and timing resolution. Use 28-SOIC for compact DIN-rail boards or 28-PDIP for legacy retrofit panels; add an external 32.768kHz crystal if real-time-clock drift must be tight. The 7KB OTP and 176-byte RAM comfortably fit finite-state-machine code for sequence control.
Recommended
Automotive Body Electronics
The PIC16C642-04E/SO is suitable for non-safety automotive body modules - mirror controllers, seat-position memories, lighting sequencers, and HVAC flaps. Its extended -40C to +125C temperature grade meets under-dash and under-hood-near requirements and the 22 I/O pins drive LEDs, switches, and small motor bridges directly. The OTP architecture is acceptable because automotive body firmware is locked at production and BOM cost is critical at high volume. Add a TVS diode on VDD and bulk capacitance on the supply rail to survive load-dump transients, and route MCLR through a 10k pull-up to a clean voltage rail for clean power-on-reset behavior.
Recommended
Consumer Keypad and LED Sequencer
Consumer products that need a low-cost human-machine interface - microwave keypads, exercise equipment, and HVAC wall thermostats - use the PIC16C642-04E/SO for its 22 I/O which can scan a 4x4 matrix keypad and drive a 4-digit seven-segment display with no external logic. The 7KB OTP holds lookup tables for menu navigation, beep patterns, and EEPROM-backed user settings. The 200ns instruction cycle means the part can multiplex the display and poll the keypad every 5ms without visible flicker or missed presses. Operate at 4MHz for low EMI, supply from 5V, and add a piezo buzzer to one PWM-capable pin for audible feedback.
Recommended
Simple Sensor Readout and Data Logger
The PIC16C642-04E/SO can host a low-power sensor readout and data logger where 8-bit ADC readings from a sensor front-end are timestamped and stored to external EEPROM. Its 176-byte RAM is large enough for buffering before page writes, and 22 I/O leaves room for SPI to the EEPROM, I2C to an RTC, and several digital sensors. SLEEP mode plus the Watchdog Timer minimizes quiescent current between samples. Operate at 4MHz from a 5V rail, and the OTP memory ensures the firmware cannot be accidentally erased by a power fault in the field. Ideal for HVAC duct sensors, agricultural soil probes, and remote building automation nodes.
Recommended
Hobby and Educational Embedded Projects
The PIC16C642-04E/SO is a teaching-grade 8-bit MCU for students learning the PIC instruction set, RISC timing, and bare-metal embedded programming. The 35-instruction RISC set is small enough to learn in a single semester and the 28-SOIC package is breadboard-friendly with a SOIC-to-DIP adapter. Because it is OTP, students should prototype with the FLASH-based PIC16F648A first and migrate to the 642 for the final build once code is locked. The 4MHz oscillator gives 1 MIPS throughput which is plenty for blinking LEDs, scanning displays, and serial UART demos at 9600 baud with software bit-banging.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C642-04E/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C642-04/SO | PIC16C642-10/SO | PIC16C642-20/SO | PIC16C642-04E/SP |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-PDIP (different SMT footprint) |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 10 MHz | 20 MHz | 4 MHz |
| Program Memory Size | 7 KB (4K x 14) OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP |
| RAM Size | 176 bytes | 176 bytes | 176 bytes | 176 bytes | 176 bytes |
| Operating Temperature Range | -40C to +125C (Extended) | 0C to +70C (Commercial) | 0C to +70C (Commercial) | 0C to +70C (Commercial) | -40C to +125C (Extended) |
| Number of I/O Pins | 22 | 22 | 22 | 22 | 22 |
| Instruction Cycle Time | 200 ns | 200 ns | 100 ns | 50 ns | 200 ns |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND |
| RoHS / Lead-Free | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes |
Key Differentiators
- Extended -40C to +125C temperature grade in 28-SOIC (vs PIC16C642-04/SO)
- Lower 4MHz clock keeps EMI low for sensitive analog designs (vs PIC16C642-20/SO)
- Same 28-SOIC pinout across the family enables design reuse (vs PIC16C642-04E/SP)
Design Notes
The PIC16C642-04E/SO requires a 5V (typical) supply on VDD (pin 20) with VSS (pin 19) as the ground reference. Place a 100nF ceramic decoupling capacitor within 5mm of VDD and a 10uF bulk capacitor on the same rail to suppress switching transients from the oscillator and I/O transitions. For battery or long-line supplies, add a series ferrite bead to isolate MCU switching noise from analog or RF sections, and place a TVS diode (e.g., 5V SMBJ) for transient protection. The exact VDD min/max range was not returned in verified web data and is marked [DATA_NEEDED] - confirm against the datasheet electrical characteristics before final design.
On the 28-SOIC PCB layout, keep the crystal/oscillator traces between OSC1 (pin 13) and OSC2 (pin 14) short and symmetric, surrounded by a ground pour, to minimize EMI and stray capacitance. Route MCLR (pin 1) to a 10k pull-up to VDD, optionally with a 100nF cap to ground for noise immunity. The ICSP programming interface uses RB6 (pin 27) as PGC clock and RB7 (pin 28) as PGD data - reserve a 2x3 or 1x6 header to the board edge and keep these traces short and free of series resistors in the programming path. Unused I/O pins should be configured as outputs low to minimize power consumption in SLEEP mode.
Estimated power at 4MHz/5V with all 22 I/O toggling: ICC typically 5-10 mA, well within the part's rating. Because the PIC16C642 is OTP, do not attempt in-circuit re-programming once the device is sealed; plan for prototype iteration on a FLASH-based PIC16F648A-I/SO (same 28-SOIC pinout) and migrate to the 642 only after the firmware is fully validated. Do not drive I/O pins above VDD or below VSS; use series resistors when driving inductive loads. The Watchdog Timer must be enabled in noisy environments to recover from transient upsets, and the configuration fuses (watchdog, oscillator, code protection) must be set correctly at programming time - they cannot be changed on OTP parts without a re-spin.
Compliance Information
RoHS compliant and lead-free per Microchip product page. Not AEC-Q100 qualified; for AEC-Q100 automotive applications use a PIC18 or dsPIC with explicit AEC-Q100 screening. REACH compliance assumed from Microchip standard declarations; halogen-free status not specified in the verified web data.
