PIC16LC781-I/SS - 8-bit 20MHz MCU 1.75KB OTP 20-SSOP | Microchip
MPN: PIC16LC781-I/SS ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.76 | $2.76 |
| 10 | $2.55 | $25.50 |
| 100 | $2.3 | $230.00 |
| 500 | $2.12 | $1,060.00 |
| 1,000 | $1.97 | $1,970.00 |
PIC16LC781-I/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, memory (program + data), and peripheral interfaces onto one piece of silicon. Within the system hierarchy, a microcontroller sits below a microprocessor (MPU) and is optimized for embedded control rather than general-purpose computing. PIC microcontrollers use a RISC Harvard architecture, which separates program and data memory buses so the core can fetch an instruction and read data in the same clock cycle, enabling deterministic single-cycle execution for most instructions.
Key features of the PIC16LC781-I/SS include its 20 MHz maximum clock rate, low-power LC process variant (the "LC" suffix), integrated 8-channel 8-bit ADC, dual analog comparators, and a programmable reference voltage output. The 16 I/O pins are shared between digital GPIO and analog peripheral functions, and the OTP (One-Time Programmable) program memory allows factory or prototyping programming with no erase window. Watchdog timer with on-chip RC oscillator, power-on reset, brown-out detect, and code protection round out the on-chip feature set.
Architecturally, the PIC16LC781 uses a 14-bit instruction word and an 8-bit data path. It supports direct, indirect, and relative addressing modes, and offers a hardware interrupt controller with context saving. Compared to flash-based PIC16F variants, the LC781 trades reprogrammability for lower cost and a simpler process, which historically made it popular in cost-sensitive high-volume appliance and consumer products.
Typical applications include white-goods control (washing machines, dishwashers, microwave ovens), small appliance timers and motor control loops, IR remote receiver decode, battery chargers, sensor signal conditioning, and low-cost user-interface boards. Designers pair the PIC16LC781 with discrete power devices, triacs or relays, and a small keypad/LED cluster to build complete front-panel controllers.
Designers should budget 5 mA typical supply current at 5 V/20 MHz and reduce clock to extend battery life. Because OTP memory cannot be re-flashed in-circuit, plan a development path that starts with a pin-compatible PIC16F877 or PIC16F887 emulator-style device for firmware bring-up, then moves to the LC781 for production.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, including verified cross-brand substitutes that share the SSOP-20 footprint.
Drop-in alternatives for PIC16LC781-I/SS — 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 PIC16LC781-I/SS (same form factor and footprint) — differing in Package, RoHS Status, ADC, Core Architecture, Data RAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16LC781T-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F88-I/SS
✅ Drop-In✓ In Stock
$3.08 / Unit
View Datasheet →PIC16F877A-I/SS
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC16LC781-I/SO
✅ Drop-In✓ In Stock
$2.46 / Unit
View Datasheet →PIC16LC781-I/SS Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Series | PIC16 |
| Core Processor | PIC |
| Core Size | 8-bit |
| Core Architecture | RISC Harvard |
| Instruction Word Width | 14-bit |
| Maximum Clock Frequency | 20 MHz |
| Program Memory Size | 1.75 KB (1K x 14) |
| Program Memory Type | OTP (One-Time Programmable) |
| RAM Size | 128 B |
| Number of I/O Pins | 16 |
| Number of ADC Channels | 8 |
| ADC Resolution | 8-bit |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| Temperature Grade | Industrial |
| Package | 20-pin SSOP (Shrink Small Outline Package) |
| Mounting Type | Surface Mount |
| Terminal Form | Gull Wing |
| Integrated Analog Comparators | 2 |
| Programmable Voltage Reference | Yes |
| Watchdog Timer | Yes (with on-chip RC oscillator) |
| Brown-out Detect / Power-on Reset | Yes |
| RoHS Status | Compliant |
PIC16LC781-I/SS Pin Configuration
| Pin 1 | MCLR/VPP — Master clear (reset) input / programming voltage input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / ADC channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / ADC channel 1 |
| Pin 4 | RA2/AN2/VREF- — PORTA bit 2 / ADC channel 2 / negative voltage reference |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / ADC channel 3 / positive voltage reference |
| Pin 6 | RA4/AN4/T0CKI — PORTA bit 4 / ADC channel 4 / Timer 0 clock input |
| Pin 7 | RA5/AN5/SS — PORTA bit 5 / ADC channel 5 / SPI slave select |
| Pin 8 | OSC1/CLKIN — Crystal oscillator input / external clock input |
| Pin 9 | OSC2/CLKOUT — Crystal oscillator output / clock output |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer 1 oscillator output / Timer 1 clock input |
| Pin 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer 1 oscillator input / CCP2 module |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / CCP1 module |
| Pin 13 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 17 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 18 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 19 | RB1 — PORTB bit 1 |
| Pin 20 | RB2 — PORTB bit 2 |
Typical Applications
PIC16LC781-I/SS is suitable for 6 applications: White Goods Control (Washing Machines, Dishwashers), Microwave Oven Control Board, Battery Charger Controller, IR Remote Receiver Decoder, Small Appliance Timer (Coffee Maker, Toaster Oven), Sensor Signal Conditioning Front-End.
White Goods Control (Washing Machines, Dishwashers)
The PIC16LC781-I/SS fits white-goods main control boards because its 8-bit PIC16 RISC core delivers deterministic single-cycle instruction execution at 20 MHz, which is essential for tight motor-control loop timing. The 1.75 KB OTP holds the entire state machine for wash-cycle sequencing, water-level sensing, and triac-driven heater control, while the 8-channel 8-bit ADC reads temperature, turbidity, and load-weight sensors. The 16 GPIO pins directly drive 7-segment LED clusters, buzzer, relay coils, and triac gates without external muxing. Industrial -40 C to +85 C temperature range tolerates under-cabinet heat in enclosed appliances.
Recommended
Microwave Oven Control Board
Microwave oven front-panel controllers use the PIC16LC781-I/SS because its 1.75 KB OTP comfortably stores keypad-debounce state machines, magnetron timing logic, and inverter control state graphs. The 8-bit ADC reads humidity-sensor and weight-sensor inputs for auto-cook programs, while the dual analog comparators generate hardware interrupts for door-switch safety interlocks. The 20-MHz instruction rate ensures response latency below 50 us, well inside the IEC 60705 safety envelope. The 20-pin SSOP footprint is small enough to fit behind the keypad PCB alongside the display driver.
Recommended
Battery Charger Controller
Lead-acid and NiMH charger designs use the PIC16LC781-I/SS as the supervisory MCU because its 8-bit ADC monitors battery voltage and charge current with 8 mV resolution at a 5 V reference - sufficient for charger termination detection. The on-chip programmable voltage reference stabilizes the ADC full-scale across temperature. OTP memory locks the charge algorithm at production, preventing field tampering with safety parameters. The low LC-process quiescent current extends standby life in float-charged backup applications.
Recommended
IR Remote Receiver Decoder
Universal-learning remote controls use the PIC16LC781-I/SS to decode RC5, NEC, and SIRC IR protocols. The 20 MHz clock delivers 1 us instruction resolution, adequate for the 560 us NEC leader pulse timing. The 128-byte RAM holds learned code tables for up to 16 devices. OTP memory locks the production firmware and prevents reverse engineering of the protocol stack. The 16 I/O pins drive an LCD, keypad matrix, and IR LED transmitter without external logic.
Recommended
Small Appliance Timer (Coffee Maker, Toaster Oven)
Appliance timer boards use the PIC16LC781-I/SS because the OTP memory economically stores fixed time-of-day, brew-strength, and toast-shade lookup tables. The on-chip watchdog timer with dedicated RC oscillator protects against mains-transient-induced firmware lockup - critical for unattended kitchen appliances. Brown-out detect ensures clean restart after power cycling. The 8-bit ADC reads NTC thermistor temperature for closed-loop toast-color control, while GPIO directly drives 7-segment displays and buzzer indicators.
Recommended
Sensor Signal Conditioning Front-End
Industrial sensor-interface boards use the PIC16LC781-I/SS as a local signal-conditioning MCU because its dual analog comparators and 8-bit ADC combine for threshold detection plus linear measurement. The 20-MIPS throughput runs digital filtering (moving average, hysteresis) on thermocouple, RTD, or strain-gauge inputs. OTP locks the calibration constants. The SSOP-20 package fits inside standard sensor housings. Industrial temperature grade handles factory-floor ambient.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC781-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LC781T-I/SS | PIC16F88-I/SS | PIC16LC781-I/SO |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-pin SSOP | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SOIC - different footprint |
| Program Memory | 1.75 KB OTP | 1.75 KB OTP | 4 KB Flash | 1.75 KB OTP |
| RAM Size | 128 B | 128 B | 368 B | 128 B |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| ADC Resolution | 8-bit | 8-bit | 10-bit | 8-bit |
| I/O Pins | 16 | 16 | 16 | 16 |
| Memory Type | OTP | OTP | Flash (reprogrammable) | OTP |
| Lifecycle Status | Last-time-buy | Last-time-buy | Active | Last-time-buy |
Key Differentiators
- Single-cycle 14-bit RISC core at 20 MHz in OTP memory (vs PIC16F88-I/SS)
- On-chip dual analog comparators and programmable voltage reference (vs PIC16LC781T-I/SS)
- Industrial -40 C to +85 C operating range with brown-out detect (vs PIC16F88-I/SS)
Design Notes
Because the PIC16LC781-I/SS uses OTP program memory, firmware bugs cannot be patched in the field. Allocate at least 20% of the 1.75 KB budget for a bootloader-style upgrade stub, even though OTP precludes re-flashing - the stub enables in-system verification on first power-up. For development, prototype on a flash-based PIC16F88-I/SS (same SSOP-20 footprint) to iterate firmware freely, then port to the LC781 for production.
Estimated: at Vdd = 5 V and Fosc = 20 MHz, typical supply current is approximately 5 mA. Add decoupling: place a 100 nF ceramic between VDD (pin 20) and VSS (pin 19) within 5 mm of the package, plus a 10 uF bulk capacitor at the regulator output. For brown-out protection, ensure the regulator's fall time at power-down is slower than the BOD re-arm time so the device exits reset cleanly.
Keep the crystal or resonator within 5 mm of OSC1 (pin 8) and OSC2 (pin 9) with short, symmetric traces. Place a ground guard ring around the oscillator cell to keep digital switching noise out of the clock. For ADC accuracy, route AVdd/AVss (tied to VDD/VSS) separately from noisy digital rails and add a ferrite bead if analog readings show more than 1 LSB of jitter.
Compliance Information
RoHS compliant per distributor listings. Not AEC-Q100 qualified; the LC781 is targeted at consumer/industrial appliances, not automotive.
