PIC16C781-I/SO - 8-bit MCU 1.75KB OTP 20MHz 20-SOIC | Microchip
MPN: PIC16C781-I/SO ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.68 | $3.68 |
| 10 | $3.4 | $34.00 |
| 100 | $2.98 | $298.00 |
| 500 | $2.62 | $1,310.00 |
| 1,000 | $2.35 | $2,350.00 |
PIC16C781-I/SO Overview
An OTP microcontroller is a microcontroller whose program memory is written once (by the user or factory) and is non-erasable. OTP devices sit between the development-friendly Flash MCUs and the higher-cost, factory-masked ROM MCUs in Microchip's product hierarchy, making them attractive for low-to-medium volume production where the cost-per-unit advantage over Flash is significant but full ROM mask NRE is not justified. The PIC16C781 is a member of Microchip's PIC16 mid-range 8-bit core family and uses a 14-bit instruction word.
Key on-chip features include 1.75 KB OTP program memory, 128 bytes of data RAM, 16 digital I/O pins with individual direction control, an 8-channel 8-bit A/D converter, an 8-bit D/A output, a single on-chip op-amp, two analog comparators, a PSMC (Programmable Switch-Mode Controller) module for direct power-supply regulation, an 8-bit timer/counter (TMR0), a 16-bit timer/counter (TMR1), and a Watchdog Timer with its own on-chip RC oscillator for maximum reliability. The PSMC makes the PIC16C781 particularly distinctive: it allows the MCU to directly implement closed-loop control of switching power supplies without an external PWM controller IC.
Typical applications include SMPS (switch-mode power supply) primary-side control, battery chargers, LED drivers, fan/motor speed controllers, and any 5V system that needs on-board analog signal conditioning plus 8-bit digital control. The integrated op-amp and comparators let the designer build current-sense amplifiers and feedback loops around the core without external analog ICs.
When designing with this part, note that OTP memory cannot be reprogrammed in-circuit; firmware must be programmed before or during board assembly using a Microchip device programmer. The PSMC peripheral requires careful PWM dead-time and frequency programming to avoid shoot-through in the external FET bridge. Industrial-temperature range is denoted by the "I" suffix.
Drop-in alternatives for PIC16C781-I/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 PIC16C781-I/SO (same form factor and footprint) — differing in Operating Temperature, Package, A/D Converter, Core, D/A Converter.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C781T-I/SO
✅ Drop-In✓ In Stock
$5.85 / Unit
View Datasheet →PIC16F785-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C782-I/SO
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16F882-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C711-20I/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.95 / Unit
View Datasheet →PIC16C716-I/SO
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C781-I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 mid-range 8-bit RISC |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 1.75 KB (1K x 14) |
| Data RAM | 128 bytes |
| Maximum Clock Frequency | 20 MHz |
| Supply Voltage | 2.0 V to 5.5 V (5.5 V max per spec) |
| Digital I/O Pins | 16 |
| A/D Converter | 8-bit, 8 channels |
| D/A Converter | 8-bit, 1 channel |
| On-Chip Operational Amplifier | 1 |
| Analog Comparators | 2 |
| PSMC Peripheral | Yes (Programmable Switch-Mode Controller) |
| Timers | TMR0 (8-bit), TMR1 (16-bit), WDT |
| Operating Temperature | -40C to +85C (Industrial, "I" suffix) |
| Package | 20-SOIC (0.295 inch / 7.50 mm body) |
| Instruction Set | 14-bit, 35 single-word instructions |
| Mounting Type | Surface Mount |
PIC16C781-I/SO Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input channel 1 |
| Pin 4 | RA2/AN2/CVREF — PORTA bit 2 / analog input channel 2 / comparator voltage reference output |
| Pin 5 | RA3/AN3 — PORTA bit 3 / analog input channel 3 |
| Pin 6 | RA4/AN4 — PORTA bit 4 / analog input channel 4 |
| Pin 7 | RA5/AN5 — PORTA bit 5 / analog input channel 5 |
| Pin 8 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 9 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 11 | RC1 — PORTC bit 1 |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / Capture-Compare-PWM1 |
| Pin 13 | RC3 — PORTC bit 3 |
| Pin 14 | RC4 — PORTC bit 4 |
| Pin 15 | RC5 — PORTC bit 5 |
| Pin 16 | RC6 — PORTC bit 6 |
| Pin 17 | RC7 — PORTC bit 7 |
| Pin 18 | VSS — Ground reference |
| Pin 19 | VDD — Positive supply voltage |
| Pin 20 | RB0/INT — PORTB bit 0 / external interrupt input |
Typical Applications
PIC16C781-I/SO is suitable for 6 applications: Switch-Mode Power Supply (SMPS) Primary-Side Control, Battery Charger Controller, LED Driver and Lighting Control, Fan and DC Motor Speed Controller, Industrial Sensor Signal Conditioning, Appliance Control Boards.
Switch-Mode Power Supply (SMPS) Primary-Side Control
The PIC16C781-I/SO's integrated PSMC peripheral generates programmable PWM outputs with dead-time control, allowing direct closed-loop control of a primary-side switching FET bridge without an external PWM controller IC. The 8-channel 8-bit A/D reads output voltage and current, the on-chip op-amp conditions the current-sense signal, and the two comparators provide fast fault-input paths for over-current protection. The 20 MHz instruction rate keeps the control loop well under 10 us, sufficing for 50-200 kHz SMPS designs in 5V-48V systems.
Recommended
Battery Charger Controller
The PIC16C781-I/SO fits single-cell and multi-cell battery charger designs because the PSMC drives the charging-FET PWM, the on-chip op-amp amplifies the current-sense shunt signal, and the 8-bit A/D digitizes battery voltage and pack temperature for the charge-state algorithm. Two analog comparators implement fast over-voltage and over-current cutoff paths independent of firmware timing. Industrial temperature range (-40C to +85C) supports outdoor and automotive-cabin charger applications where the MCU sits near the battery thermal mass.
Recommended
LED Driver and Lighting Control
Constant-current LED drivers benefit from the PIC16C781-I/SO's PSMC PWM output, op-amp current-sense amplifier, and 8-bit D/A converter (which can serve as an analog reference for a high-side current-sense loop). The 16 digital I/O pins allow direct drive of status LEDs, button inputs, and DMX-style dimming interfaces. The 5V supply rail is convenient for driving logic-level power FETs in buck and boost LED topologies, and the 20 MHz clock supports 16-bit PWM resolution at 200 kHz switching frequency.
Recommended
Fan and DC Motor Speed Controller
Closed-loop BLDC and brushed-DC motor control up to a few hundred Hz electrical frequency fits the PIC16C781-I/SO: the PSMC provides the complementary PWM outputs for the H-bridge, the op-amp amplifies the shunt current-sense, the 8-bit A/D reads back EMF or tachometer feedback, and the two comparators handle over-current and over-temperature hardware trips. At 20 MHz, the firmware has ~200 ns per instruction to run a commutation table - sufficient for sensorless trapezoidal commutation of small fan motors.
Recommended
Industrial Sensor Signal Conditioning
The PIC16C781-I/SO's on-chip op-amp and dual comparators let it serve as a sensor front-end: amplify a thermocouple or strain-gauge signal, digitize it with the 8-bit A/D, and apply linearization or alarm thresholds. The 16 digital I/O handle switch debouncing, relay drivers, and indicator LEDs. Industrial temperature grade and 5V supply tolerance make this part appropriate for factory-floor panels, HVAC controllers, and process-instrumentation sub-assemblies.
Recommended
Appliance Control Boards
Cost-sensitive appliance control boards (coffee machines, washing machines, small kitchen appliances) benefit from the PIC16C781-I/SO's integrated analog peripherals that replace 2-3 external ICs. The PSMC drives a TRIAC or relay for heater/pump control, the op-amp reads NTC thermistor temperature, the comparators detect zero-cross for line-voltage TRIAC firing, and the 8-bit A/D monitors supply voltage and user-knob position. Industrial temp grade and 20-SOIC surface-mount package suit through-hole-replacement SMT conversions of legacy appliance boards.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C781-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C781T-I/SO | PIC16F785-I/SO | PIC16C782-I/SO | PIC16C711-20I/SO | PIC16C716-I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-SOIC (0.295 inch) | 20-SOIC - same | 20-SOIC - same | 20-SOIC - same | 20-SOIC - same | 20-SOIC - same |
| Program Memory | 1.75 KB OTP | 1.75 KB OTP | 3.5 KB Flash | 1.75 KB OTP | 1.75 KB OTP | 3.5 KB OTP |
| RAM | 128 B | 128 B | 128 B | 128 B | 68 B | 128 B |
| Max Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| PSMC Peripheral | Yes | Yes | Yes | Yes | No | No |
| On-Chip Op-Amp | 1 | 1 | 1 | 1 | 0 | 0 |
| Memory Type | OTP | OTP | Flash (reprogrammable) | OTP | OTP | OTP |
| Operating Temperature | -40C to +85C (I suffix) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- On-chip PSMC peripheral for SMPS control without external PWM IC (vs PIC16C711-20I/SO)
- Higher RAM and richer analog peripheral set vs legacy PIC16C711 (vs PIC16C711-20I/SO)
- Flash reprogrammability with same SOIC-20 footprint and PSMC peripheral (vs PIC16F785-I/SO)
Design Notes
OTP memory cannot be reprogrammed in-circuit; firmware must be programmed using a Microchip device programmer (e.g., PICSTART Plus or MPLAB PM3) before or during board assembly. Any firmware bug discovered after programming requires replacing the silicon. For prototypes and field-updateable products, choose the Flash-based PIC16F785-I/SO instead. Per the Microchip PIC16C781 datasheet, programming is performed via the ICSP interface on pins RB6/RB7 plus MCLR/VPP.
PSMC PWM outputs driving an external FET bridge need careful PCB layout: keep the PSMC output traces short and away from analog input traces (A/D, op-amp, comparator inputs) to prevent switching-noise coupling into the analog signal path. Place the PSMC output bypass capacitor and gate-drive resistor within 5 mm of the FET gate. According to the Microchip PIC16C781 datasheet, the PSMC PWM outputs are on dedicated pins that must be configured correctly before enabling the peripheral.
Decouple VDD with a 100 nF ceramic capacitor as close to pins 19-20 as possible, plus a bulk 10 uF tantalum or aluminum on the board power entry. The PIC16C781-I/SO has multiple analog peripherals (A/D, D/A, op-amp, comparators) that benefit from a quiet analog supply - consider a small ferrite bead between VDD and AVDD if the board shares noisy digital supply with analog signal conditioning. Decoupling is critical when the PSMC is switching high-current loads.
Compliance Information
RoHS/REACH/lead-free status not stated in the verified web data for this OTP part. Mark [DATA_NEEDED] in specs. Microchip publishes material-composition data on its product page; engineers should consult https://www.microchip.com/en-us/product/PIC16C781 for the latest environmental certification. Conflict-minerals compliance statement available via Microchip's corporate sustainability page.
