PIC16LC642-04/SO - 8-Bit 4MHz OTP MCU 7KB | Microchip
MPN: PIC16LC642-04/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.9 | $29.00 |
| 100 | $2.55 | $255.00 |
| 500 | $2.25 | $1,125.00 |
| 1,000 | $2 | $2,000.00 |
PIC16LC642-04/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, memory, and programmable I/O peripherals on a single die. The PIC16C/PIC16LC family represents one of the earliest and most successful 8-bit RISC architectures, with the PIC16LC variants optimized for low-voltage (3.0V to 5.5V) operation. Within the broader taxonomy, this part sits in the hierarchy: microcontroller -> 8-bit MCU -> RISC MCU -> embedded controller -> semiconductor IC. The 'LC' designation specifically indicates CMOS low-power operation, and the '04' speed suffix denotes a 4MHz oscillator/clock limit.
Key features include 35 single-word instructions (most single-cycle, with program branches taking two cycles), a Harvard architecture with separate program and data buses, and OTP (One-Time Programmable) memory that allows programming exactly once, making it ideal for mature, stable-volume products where firmware is finalized. The 22 I/O pins support direct LED drive, TTL-compatible inputs, and standard peripheral interfacing.
Technical depth: The PIC16LC642 uses a 14-bit instruction word with an 8-bit data path, providing a code-efficient instruction set for C and assembly development. The integrated RISC core delivers deterministic interrupt response in as little as one instruction cycle, which is critical for real-time control loops. Internal peripherals include timers, a watchdog timer, and an analog comparator that supports brown-out and voltage-monitoring functions.
Typical applications include industrial control nodes, appliance controllers, automotive sub-systems (non-safety-critical), consumer electronics, and legacy embedded products that require 5V-tolerant logic. With 7KB of OTP and 176 bytes of RAM, the device targets medium-complexity control tasks that do not require field re-programming.
When designing with this device, ensure the MCLR reset circuit includes the proper pull-up and decoupling as shown in the Microchip PIC16C6xx reference design. The OTP memory has no revision capability, so production firmware must be fully validated before programming.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes that go beyond the manufacturer datasheet, giving engineers a single reference for sourcing and validation decisions.
Drop-in alternatives for PIC16LC642-04/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 PIC16LC642-04/SO (same form factor and footprint) — differing in Core Architecture, Package Type, Program Memory Type, Supply Voltage Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
No drop-in alternatives available for this product.
Request AlternativesPIC16LC642-04/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC® 16C |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 176 bytes |
| Maximum Clock Speed | 4 MHz |
| Supply Voltage Range | 3 V to 5.5 V |
| Number of I/O Pins | 22 |
| Instruction Set | 35 single-word instructions |
| Instruction Cycle | 200 ns at 20 MHz equivalent cycle time |
| Package Type | 28-SOIC |
| Mounting Type | Surface Mount |
| I/O Compatibility | TTL-compatible inputs |
| Peripherals | Timers, Watchdog Timer, Analog Comparator |
PIC16LC642-04/SO Pin Configuration
| Pin 1 | MCLR — Master Clear (Reset) input, active low |
| Pin 2 | RA0 — PORTA bit 0 (digital I/O) |
| Pin 3 | RA1 — PORTA bit 1 (digital I/O) |
| Pin 4 | RA2 — PORTA bit 2 (digital I/O) |
| Pin 5 | RA3 — PORTA bit 3 (digital I/O) |
| Pin 6 | RA4 — PORTA bit 4 (digital I/O, open-drain capable) |
| Pin 7 | RA5 — PORTA bit 5 (digital I/O) |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1 — Oscillator input / external clock |
| Pin 10 | OSC2 — Oscillator output |
| Pin 11 | RC0 — PORTC bit 0 (digital I/O) |
| Pin 12 | RC1 — PORTC bit 1 (digital I/O) |
| Pin 13 | RC2 — PORTC bit 2 (digital I/O) |
| Pin 14 | RC3 — PORTC bit 3 (digital I/O) |
| Pin 15 | RC4 — PORTC bit 4 (digital I/O) |
| Pin 16 | RC5 — PORTC bit 5 (digital I/O) |
| Pin 17 | RC6 — PORTC bit 6 (digital I/O) |
| Pin 18 | RC7 — PORTC bit 7 (digital I/O) |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage |
| Pin 21 | RB0 — PORTB bit 0 (digital I/O, external interrupt capable) |
| Pin 22 | RB1 — PORTB bit 1 (digital I/O) |
| Pin 23 | RB2 — PORTB bit 2 (digital I/O) |
| Pin 24 | RB3 — PORTB bit 3 (digital I/O) |
| Pin 25 | RB4 — PORTB bit 4 (digital I/O, interrupt-on-change) |
| Pin 26 | RB5 — PORTB bit 5 (digital I/O, interrupt-on-change) |
| Pin 27 | RB6 — PORTB bit 6 (digital I/O, ICSP clock) |
| Pin 28 | RB7 — PORTB bit 7 (digital I/O, ICSP data) |
Typical Applications
PIC16LC642-04/SO is suitable for 7 applications: Industrial Control Nodes, Home Appliance Controllers, Automotive Sub-Systems (Non-Safety), Consumer Electronics Devices, Sensor Interface Modules, Legacy Embedded Products / Repair, Battery-Operated Devices.
Industrial Control Nodes
The PIC16LC642-04/SO fits industrial control nodes because its 4 MHz core delivers deterministic 200 ns instruction cycles, sufficient for sensor polling, actuator drive, and Modbus-style UART traffic on shop-floor networks. The 22 I/O pins map cleanly to typical RTU channel counts (8 to 16 digital inputs plus 4 to 8 relay outputs) and the 3.0V to 5.5V supply range accepts both 24V-to-5V buck-derived rails and battery backup without level translation. Compared with the PIC16F882-I/SO drop-in upgrade, this OTP part is preferable where firmware lock-down is a compliance requirement and field updates are not desired.
Recommended
Home Appliance Controllers
The PIC16LC642-04/SO is a strong fit for home appliance controllers (washing machines, microwave ovens, HVAC actuators) because its 7KB OTP memory stores fixed control algorithms, the 22 I/O accommodate relay coils, keypads, and seven-segment or LCD display drivers, and the 35-instruction RISC core makes it easy to certify timing-critical code paths. The LC variant operates from 3.0V to 5.5V, simplifying designs that need to share a single supply with opto-isolated 5V gate drivers. For designers considering migration, the PIC16F882-I/SO is the flash-based pin-compatible successor for late-stage firmware changes.
Recommended
Automotive Sub-Systems (Non-Safety)
The PIC16LC642-04/SO serves automotive sub-systems such as HVAC flap motors, accessory controllers, and lighting dimmer sub-modules where AEC-Q100 full qualification is not required but industrial-grade temperature tolerance matters. The -40 to +85 C range covers cabin and under-hood periphery environments, while the 22 I/O and 176-byte RAM suit CAN-bus slave nodes and LIN-bus responder tasks. The OTP memory stabilizes firmware against unauthorized modification. For AEC-Q100 applications, migrate to PIC16F882-I/SO with full automotive qualification.
Recommended
Consumer Electronics Devices
The PIC16LC642-04/SO is well matched to consumer electronics such as remote controls, electronic toys, kitchen timers, and small appliances where low cost, 5V tolerance, and 22 user-port-pins are needed without USB or large-memory requirements. The 7KB OTP holds typical remote-control or kitchen-appliance logic comfortably, and the RISC 4 MHz core keeps active power low. Designers scaling this part in volume can migrate to the PIC16F882-I/SO for the flash variant while keeping the same SOIC-28 PCB footprint.
Recommended
Sensor Interface Modules
The PIC16LC642-04/SO suits sensor interface modules where analog signals from thermistors, photodiodes, or 4-20 mA loops must be digitized and forwarded over UART or SPI links. Its on-chip comparator and timer peripherals provide analog threshold detection and pulse counting, while 176 bytes of RAM support circular sample buffers and command parsing. The 3.0V minimum supply is ideal for battery-backed sensors. For higher-precision analog systems, add an external ADC companion such as MCP3002 or MCP3008.
Recommended
Legacy Embedded Products / Repair
The PIC16LC642-04/SO is frequently specified in legacy embedded products that have shipped for 10+ years, including industrial test equipment, vending machine controllers, and older HVAC sub-systems. For maintenance and repair operations, this OTP part remains in production as an active Microchip SKU and is stocked at major distributors. The 28-SOIC footprint allows technicians to replace surface-mounted units on existing PCBs without board rework. For new designs requiring flash memory, the PIC16F882-I/SO is the recommended modern successor.
Recommended
Battery-Operated Devices
The PIC16LC642-04/SO fits battery-operated devices thanks to the LC variant's low-voltage 3.0V operation, which allows direct connection to 2x AA alkaline cells (3.0V nominal) or 1x Li-Ion cell (3.3V to 4.2V) without a boost converter. The 4 MHz clock keeps dynamic current low (typically 2 mA at 5V, 1 mA at 3V active), and the OTP memory avoids in-circuit reprogramming current spikes. Pair with an MCP1700 LDO for stable rail conditioning during transmission events from companion RF modules.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC642-04/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LC642-04I/SO | PIC16LC642T-04/SO | PIC16C642-04/SO | PIC16F882-I/SO | PIC16F883-I/SO |
|---|---|---|---|---|---|---|
| Package | 28-SOIC | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | 7KB OTP | 7KB OTP | 7KB OTP | 7KB OTP | 3.5KB Flash | 7KB Flash |
| Program Memory Size | 7 KB | 7 KB | 7 KB | 7 KB | 3.5 KB | 7 KB |
| Maximum Clock Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 20 MHz |
| Supply Voltage Range | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 4.5 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| Number of I/O Pins | 22 | 22 | 22 | 22 | 22 | 24 |
| Temperature Grade | Commercial | Industrial | Commercial | Commercial | Industrial | Industrial |
Key Differentiators
- OTP firmware lockdown for production stability (vs PIC16F882-I/SO)
- 22 I/O pins in 28-SOIC package (vs PIC16F883-I/SO)
- Low-voltage LC variant (3.0V min) (vs PIC16C642-04/SO)
Design Notes
The PIC16LC642-04/SO draws approximately 2 mA active current at 5V/4 MHz and approximately 5 uA in SLEEP mode. Add a 100 nF decoupling capacitor within 5 mm of the VDD pin (pin 20) and a 10 uF bulk capacitor on the VDD rail to handle LED-drive inrush on PORTC[0..7]. A low-ESR tantalum or ceramic bulk cap is recommended when driving relay coils from PORTB. Estimated: based on datasheet typical IDD figures.
For reliable ICSP programming and debug, place 1 kohm pull-up on MCLR (pin 1) and do NOT add series capacitance to MCLR - Microchip ICSP requires the pin to be sampled in-circuit. Keep the ICSP connector accessible or accessible via test pads. Estimated: pinout per PIC16C64X datasheet pin-pack chart.
When migrating PIC16LC642 firmware to PIC16F882-I/SO, note that the FLASH variant does NOT support the same code-protection fuse bits in the same configuration words - recompile with the new XC8/MPASM header file. The configuration bits for oscillator modes (HS, XT, LP, RC) map identically between LC and F parts, but WDT and BOR settings differ by family. Always re-validate boundary conditions before production.
For mixed-signal noise immunity, separate PORTA (used for analog comparator) traces from PORTB/PORTC digital traces by at least one trace-width gap, and place the analog GND reference at pin 8 (VSS) with a star-ground connection back to the power supply. The 28-SOIC package benefits from a small copper pour beneath the IC to reduce thermal rise at higher ambient temperatures.
Compliance Information
Compliance data not present in verified web data for the SOIC package variant. Microchip generally ships these PIC16C6x SKUs with full RoHS compliance under parts with 'G' suffix - verify marking on received parts.
