PIC16LC66T-04/SO - 8-bit MCU, 14KB OTP, 4MHz, 28-SOIC | Microchip
MPN: PIC16LC66T-04/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.92 | $6.92 |
| 10 | $6.18 | $61.80 |
| 100 | $5.42 | $542.00 |
| 500 | $4.78 | $2,390.00 |
| 1,000 | $4.25 | $4,250.00 |
PIC16LC66T-04/SO Overview
An 8-bit microcontroller is a small computing system on a single integrated circuit that combines a CPU, RAM, non-volatile program memory, and configurable I/O peripherals. PIC microcontrollers specifically use a RISC (Reduced Instruction Set Computer) Harvard architecture with 35 single-word instructions, where the program memory bus is separated from the data memory bus. Within the broader taxonomy, this part sits at: microcontroller -> embedded controller -> semiconductor -> integrated circuit. Microcontrollers like the PIC16LC66 are the workhorses of low-cost, deterministic embedded designs where predictability of timing matters more than raw processing throughput.
Key features include three timer/counter modules (Timer0 8-bit with prescaler, Timer1 16-bit with sleep-mode external clock support, and Timer2 8-bit), a USART module for serial communication, capture/compare/PWM (CCP) peripherals, an 8-channel 8-bit analog-to-digital converter, and on-chip oscillator options. The CMOS fully-static design allows the clock to be stopped without losing register state, enabling low-power sleep/idle modes critical for battery-operated applications.
The 'LC' prefix denotes the low-voltage CMOS process variant of the PIC16C66 family, optimized for 3.3V operation while still compatible with 5V systems. The 'T' suffix in the part number indicates tape-and-reel packaging for high-volume surface-mount assembly, while the '/SO' suffix specifies the 28-pin Small Outline IC package (SOIC-28). The PIC16C6X architecture remains widely used for cost-sensitive industrial control, consumer electronics, and educational platforms due to its deterministic instruction timing and free MPLAB development toolchain.
Typical applications include appliance control boards, simple sensor interfaces, LED lighting controllers, low-speed serial communication hubs, and educational microcontroller trainers. The wide 2.5V to 5.5V operating range allows direct battery or USB-powered deployment.
A key design consideration is that OTP program memory cannot be erased or rewritten; production code must be verified in windowed (UV-erasable) or flash-based variants before committing to OTP. For prototyping, the PIC16F66 flash variant or PIC16C66 with a JW (windowed) package is recommended.
Drop-in alternatives for PIC16LC66T-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 PIC16LC66T-04/SO (same form factor and footprint) — differing in Program Memory Size, Core Architecture, Package, Mounting Type, RAM Size.
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| Core Architecture | 8-bit RISC (PIC16C6X Harvard) |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 14KB (8K x 14 words) |
| RAM Size | 368 bytes |
| Maximum Clock Speed | 4 MHz |
| Supply Voltage Range | 2.5 V to 5.5 V |
| Number of I/O Pins | 22 |
| Number of Timers | 3 (Timer0, Timer1, Timer2) |
| ADC | 8-channel, 8-bit |
| Communication Interfaces | USART (SCI), SSP (SPI/I2C) |
| Package | 28-SOIC (0.295", 7.50mm width) |
| Mounting Type | Surface Mount |
| Packaging Media | Tape & Reel (T suffix) |
| Instruction Set | 35 single-word instructions |
PIC16LC66T-04/SO Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / Programming voltage |
| Pin 2 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / Analog input 2 / ADC VREF- |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input 3 / ADC VREF+ |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / Analog input 4 / SPI slave select |
| Pin 8 | VSS — Ground |
| Pin 9 | OSC1/CLKIN — Oscillator crystal input / external clock in |
| Pin 10 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 19 | VSS — Ground |
| Pin 20 | VDD — Positive supply voltage |
| Pin 21 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 22 | RB1 — PORTB bit 1 |
| Pin 23 | RB2 — PORTB bit 2 |
| Pin 24 | RB3/PGM — PORTB bit 3 / Low-voltage programming |
| Pin 25 | RB4 — PORTB bit 4 |
| Pin 26 | RB5 — PORTB bit 5 |
| Pin 27 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 28 | RB7/PGD — PORTB bit 7 / ICSP data |
Typical Applications
PIC16LC66T-04/SO is suitable for 6 applications: Appliance Control Boards, LED Lighting Controllers, Industrial Sensor Interface Modules, Consumer Remote Controls and IR Interfaces, Low-Speed Serial Communication Hubs, Educational Microcontroller Trainers.
Appliance Control Boards
The PIC16LC66T-04/SO's 22 I/O pins, 8-channel 8-bit ADC, and USART make it well-suited for washing machine, dishwasher, and microwave oven control boards. The wide 2.5V to 5.5V supply range allows direct connection to rectified mains-derived rails with simple regulation, and the 4 MHz / 1 MIPS throughput is sufficient for keypad scanning, relay control, sensor reading, and user-interface animation. The OTP memory enables low per-unit cost in high-volume appliance production. A typical implementation places the MCU between the power supply and the relay driver array, with the ADC reading temperature sensors and the CCP module generating PWM for motor speed control. Designers should note that OTP requires verified firmware at production commit.
Recommended
LED Lighting Controllers
The PIC16LC66T-04/SO can drive multichannel LED lighting controllers via its CCP module for PWM dimming and the 8-channel ADC for ambient light sensing. The 22 I/O pins can control multiple LED strings with MOSFET drivers while supporting DMX-style serial protocols via the USART. The 2.5V to 5.5V supply range enables direct battery or USB-powered LED strip controllers. The low-cost OTP memory is acceptable for fixed-pattern lighting products. A typical circuit places the MCU at the center of the LED driver board, with the PWM output feeding N-channel MOSFET gates for high-current LED string switching. Engineers should add flyback protection on inductive loads.
Recommended
Industrial Sensor Interface Modules
The PIC16LC66T-04/SO's 8-channel 8-bit ADC, USART, and 22 I/O pins enable multi-sensor aggregation modules that read thermocouples, pressure transducers, or digital switches and forward processed data via RS-232 or RS-485. The 2.5V to 5.5V supply range accepts 24V industrial bus power with simple regulator front-ends. The PIC RISC architecture's deterministic instruction timing simplifies sensor-sampling-rate calculations in real-time control loops. Typical usage involves reading analog sensors at fixed intervals, applying linearization in firmware, and transmitting formatted packets via the USART. Choose PIC16LC66T-04I/SO for industrial-grade temperature compliance.
Recommended
Consumer Remote Controls and IR Interfaces
The PIC16LC66T-04/SO's low power consumption, ample I/O for keypad matrix scanning, and USART make it suitable for universal remote controls, IR transceivers, and consumer automation keypads. The 14KB OTP program memory holds complex IR protocol libraries (RC5, NEC, SIRC) with margin for custom command sets. The 4 MHz clock and CMOS static design enable long battery life via sleep-mode wake-on-interrupt. A typical circuit uses Timer1 for IR carrier generation, the CCP module for protocol timing, and external transistors for IR LED drive. Use the PIC16LC66-04/SO tube variant for low-volume hand-assembled remote controls.
Recommended
Low-Speed Serial Communication Hubs
The PIC16LC66T-04/SO includes both a USART (SCI) and an SSP module supporting SPI and I2C, allowing it to bridge legacy serial peripherals to a host controller. The 22 I/O pins and 14KB OTP program memory fit multi-protocol hub firmware, including sensor-to-MQTT bridges or industrial Modbus gateway prototypes. The 2.5V to 5.5V supply range matches 3.3V and 5V serial rail levels directly without level shifters in same-rail designs. In a typical hub implementation, the MCU receives I2C sensor data and forwards it over USART as formatted ASCII or Modbus frames to a host CPU.
Recommended
Educational Microcontroller Trainers
The PIC16LC66T-04/SO is widely used in university embedded systems courses and hobbyist trainer boards due to its 28-SOIC ease-of-soldering, free MPLAB IDE toolchain, and the extensive PIC16C6X teaching materials. The 14KB program memory accommodates student projects from LED blinkers to UART-controlled displays, while the 22 I/O pins allow breadboard-friendly breakout boards exposing timers, ADC, and CCP peripherals. For student labs, the PIC16F66 flash variant is preferred because mistakes can be erased and reprogrammed thousands of times. Production final-year projects may commit to the OTP variant for cost reasons.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC66T-04/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LC66-04/SO | PIC16LC66T-04I/SO | PIC16LC66-04I/SO | PIC16F66-I/SO | PIC16LC66-04/SP | PIC16LC66-04I/SP |
|---|---|---|---|---|---|---|---|
| Package | 28-SOIC (T&R) | 28-SOIC (Tube) | 28-SOIC (T&R) | 28-SOIC (Tube) | 28-SOIC (Tube) | 28-SPDIP (through-hole) | 28-SPDIP (through-hole) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP (14KB) | OTP (14KB) | OTP (14KB) | OTP (14KB) | Flash (14KB) | OTP (14KB) | OTP (14KB) |
| Max Clock Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 4 MHz | 4 MHz |
| Supply Voltage | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.0 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V |
| Temperature Grade | Commercial (0C to +70C) | Commercial (0C to +70C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Commercial (0C to +70C) | Industrial (-40C to +85C) |
| I/O Pins | 22 | 22 | 22 | 22 | 22 | 22 | 22 |
| ADC Channels | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit | 8 x 8-bit |
| Packaging Media | Tape & Reel | Tube | Tape & Reel | Tube | Tube | Tube | Tube |
Key Differentiators
- Tape-and-reel packaging optimized for high-volume SMT assembly (vs PIC16LC66-04/SO)
- OTP memory provides lowest per-unit cost in high-volume production (vs PIC16F66-I/SO)
- Commercial temperature grade matches indoor consumer electronics specs (vs PIC16LC66T-04I/SO)
- LC low-voltage CMOS process supports 3.3V operation natively (vs PIC16C66 (standard C variant, not LC))
Design Notes
Place a 100nF ceramic decoupling capacitor as close as possible (within 5mm) to the VDD pin (pin 20) with a low-impedance ground return to pin 8 or pin 19. For designs with ADC use, add a 10uF bulk capacitor on the VDD rail. The PIC16LC66T-04/SO operating range is 2.5V to 5.5V; do not exceed 5.5V or the brown-out detector may mis-trigger. If the supply is sourced from a switching regulator, add a ferrite bead or LC filter to prevent switching noise from coupling into the analog reference and corrupting ADC readings.
OTP memory cannot be erased or reprogrammed. According to Microchip PIC16C6X datasheet guidance, prototype code MUST be developed and verified on a flash-based PIC16F66-I/SO or JW (windowed UV-erasable) variant before committing to OTP production. Once programmed, a faulty OTP device is bricked. Designers should also note that the 'T' suffix in PIC16LC66T-04/SO denotes tape-and-reel packaging for SMT assembly lines; manual prototype assembly is easier with the tube variant PIC16LC66-04/SO.
Route the MCLR/VPP pin (pin 1) with a short trace to a 10k pull-up resistor to VDD; this pin is sensitive to noise that can cause spurious resets. Place the crystal or resonator within 10mm of pins 9 (OSC1) and 10 (OSC2) with a grounded guard ring around the oscillator traces to minimize EMI coupling. For ADC accuracy, route analog inputs (RA0-RA5) away from digital switching traces like the USART lines and PWM outputs; ADC reference VREF+/VREF- should bypass with 100nF capacitors. The 28-SOIC package has no exposed thermal pad; thermal dissipation is negligible at the PIC's typical 5 to 25 mA operating current.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - this is a commercial-grade 8-bit MCU intended for consumer applications. For automotive designs, choose AEC-Q100-qualified dsPIC or PIC18 variants instead.
