PIC16C66-10/SP - 14KB OTP 8-bit MCU, 22 I/O, 10MHz | Microchip
MPN: PIC16C66-10/SP β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.84 | $5.84 |
| 10 | $5.26 | $52.60 |
| 100 | $4.61 | $461.00 |
| 500 | $4.07 | $2,035.00 |
| 1,000 | $3.62 | $3,620.00 |
PIC16C66-10/SP Overview
A PIC16C-series microcontroller is an 8-bit RISC MCU built on Microchip's classic Harvard-architecture core, executing one instruction per clock cycle except for branches. The PIC16C family belongs to the broader PIC16 mid-range product line (PIC16 -> PICmicro -> 8-bit microcontroller -> microcontroller -> embedded IC) and is positioned above the PIC12/PIC14 baseline families in pin count, memory, and peripheral integration. The PIC16C6x family specifically targets industrial and embedded-control applications that need OTP programmability for low-volume or pre-production runs.
Key features include 14KB (8K x 14) of OTP program memory, 368 bytes of data RAM, 22 general-purpose I/O pins arranged across ports A/B/C, three timers (Timer0, Timer1, Timer2), a USART for serial communications, Capture/Compare/PWM (CCP) module, and an 8-channel 8-bit A/D converter. The device supports a 200 ns instruction cycle at 10 MHz, providing 5 MIPS of throughput, and features a wide operating voltage range typical of PIC16C6x parts.
Technically, the PIC16C66 uses a 14-bit instruction word with a 35-instruction RISC instruction set, allowing efficient C and assembly development through MPLAB IDE and the Hi-Tech PICC compiler. The 28-pin SPDIP package is pin-compatible with the PIC16C65 and PIC16C64 families as well as later PIC16F-series flash replacements such as the PIC16F76, simplifying migration paths for legacy designs.
Typical applications include industrial control logic, sensor interfacing, low-speed motor control, instrumentation, and consumer-electronics subsystems where OTP memory is acceptable. The PIC16C66-10/SP is also widely used as a maintenance part for legacy equipment where the original OTP MCU must be replaced with the same part.
When designing with this device, note that OTP memory cannot be reprogrammed in-circuit, so code must be fully validated before the part is socketed. A windowed (JW) ceramic variant is available for development and code iteration, while production builds typically use the OTP SPDIP or SOIC variants.
This page synthesizes distributor pricing from 6 active suppliers, same-package drop-in alternatives, and practical design notes not found in the standalone datasheet, providing engineers a single source for sourcing and replacement decisions for the legacy PIC16C66-10/SP.
Drop-in alternatives for PIC16C66-10/SP β 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 PIC16C66-10/SP (same form factor and footprint) β differing in Mounting Type, Package, I/O Pins, Timers, Core Architecture.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C66-10I/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16C65B-20I/P
β Drop-Inβ In Stock
$5.42 / Unit
View Datasheet βPIC16C65B-04I/P
β Drop-Inβ In Stock
$3.75 / Unit
View Datasheet βPIC16F76-I/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16C66-10/SP Maximum Ratings & Electrical Characteristics
| Core | PIC16 (8-bit RISC, Harvard architecture) |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 14 KB (8K x 14 words) |
| Data RAM | 368 bytes |
| Maximum Clock Frequency | 10 MHz |
| Instruction Cycle | 200 ns |
| Throughput | 5 MIPS |
| Operating Voltage | 5 V (typical PIC16C6x range) |
| I/O Pins | 22 |
| Timers | 3 (Timer0, Timer1, Timer2) |
| A/D Converter | 8-channel, 8-bit |
| Serial Interface | USART (SCI) |
| CCP Module | Capture / Compare / PWM |
| Package | 28-pin SPDIP (Skinny DIP, 0.300" / 7.62 mm) |
| Mounting Type | Through-Hole |
| Instruction Set | 35 single-word instructions |
PIC16C66-10/SP Pin Configuration
| Pin 1 | MCLR/VPP β Master Clear (Reset) input / Programming voltage input |
| Pin 2 | RA0/AN0 β Port A bit 0 / Analog input 0 |
| Pin 3 | RA1/AN1 β Port A bit 1 / Analog input 1 |
| Pin 4 | RA2/AN2 β Port A bit 2 / Analog input 2 |
| Pin 5 | RA3/AN3/VREF β Port A bit 3 / Analog input 3 / A/D reference |
| Pin 6 | RA4/T0CKI β Port A bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS β Port A bit 5 / Analog input 4 / SPI slave select |
| Pin 8 | VSS β Ground reference |
| Pin 9 | OSC1/CLKIN β Oscillator crystal input / external clock input |
| Pin 10 | OSC2/CLKOUT β Oscillator crystal output / clock output |
| Pin 11 | RC0/T1OSO/T1CKI β Port C bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 β Port C bit 1 / Timer1 oscillator input / CCP2 input/output |
| Pin 13 | RC2/CCP1 β Port C bit 2 / CCP1 input/output |
| Pin 14 | RC3/SCK/SCL β Port C bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA β Port C bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO β Port C bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK β Port C bit 6 / USART transmit / USART clock |
| Pin 18 | RC7/RX/DT β Port C bit 7 / USART receive / USART data |
| Pin 19 | VSS β Ground reference |
| Pin 20 | VDD β Positive supply voltage (+5V) |
| Pin 21 | RB0/INT β Port B bit 0 / External interrupt input |
| Pin 22 | RB1 β Port B bit 1 |
| Pin 23 | RB2 β Port B bit 2 |
| Pin 24 | RB3 β Port B bit 3 |
| Pin 25 | RB4 β Port B bit 4 |
| Pin 26 | RB5 β Port B bit 5 |
| Pin 27 | RB6/PGC β Port B bit 6 / ICSP clock input |
| Pin 28 | RB7/PGD β Port B bit 7 / ICSP data input/output |
Typical Applications
PIC16C66-10/SP is suitable for 7 applications: Industrial Control Logic, Legacy Equipment Maintenance, Sensor Interfacing Modules, Low-Speed Motor Control, Consumer Electronics Subsystems, Instrumentation Front-Ends, Automotive Subsystems (Legacy).
Industrial Control Logic
The PIC16C66-10/SP fits industrial control logic boards thanks to its 22 digital I/O pins, 5 MIPS throughput at 10 MHz, and 14 KB OTP program memory that holds substantial ladder-logic-style state machines. Its CCP module provides PWM outputs for valve and actuator control, while the 8-channel 8-bit A/D reads analog sensor signals from temperature, pressure, and flow transducers. The 5V supply rail and CMOS process give strong noise immunity in 24V-derived industrial power systems. With 22 I/O available, the device can drive indicator lamps, keypads, and discrete outputs without external expanders.
Recommended
Legacy Equipment Maintenance
The PIC16C66-10/SP is widely used as a maintenance replacement for original PIC16C66-10/SP parts installed in legacy factory equipment, medical instruments, and aerospace subsystems where firmware was originally deployed as OTP. Its identical pinout and timing to the original part guarantees firmware compatibility without PCB rework. The 28-SPDIP package is socket-compatible with prior installations, simplifying field replacement. Because the original OTP firmware image is fully specified, drop-in identical replacements (PIC16C66-10/SP, PIC16C66-10I/SP) ensure continued operation of certified systems.
Recommended
Sensor Interfacing Modules
The PIC16C66-10/SP suits sensor interfacing modules where multiple analog inputs need conditioning and digital outputs need coordinated timing. The 8-channel 8-bit A/D converter reads thermistors, photocells, and potentiometers directly, while the USART outputs data to a host controller or display. Its 368 bytes of RAM provide scratch storage for moving-average filtering and calibration tables. The CCP module generates precise timing pulses for ultrasonic or IR distance sensors, and the 22 I/O pins drive segment LCDs or LED status indicators without external logic.
Recommended
Low-Speed Motor Control
The PIC16C66-10/SP handles low-speed brushed DC and stepper motor control in appliance, HVAC, and small industrial drives. The CCP module generates PWM signals up to 10 kHz at 10-bit resolution, suitable for DC motor speed regulation and stepper drive sequencing. Three timers (Timer0, Timer1, Timer2) provide independent time bases for commutation, debounce, and watchdog functions. The 22 I/O lines interface to H-bridge drivers, optical encoders, and limit switches directly. Its OTP nature ensures firmware stability against accidental erasure in field-deployed drives.
Recommended
Consumer Electronics Subsystems
The PIC16C66-10/SP provides cost-effective control in consumer electronics such as washing machines, microwave ovens, and audio mixers. Its 14 KB OTP holds appliance state machines, button-debounce routines, and user-interface logic. The USART enables communication with a main controller or display board, while the A/D reads keypad resistance ladders or humidity sensors. With 22 I/O, the device directly drives 7-segment displays, relays, and triac interfaces. The industrial-grade CMOS process and wide operating voltage ensure reliability in consumer-grade power environments.
Recommended
Instrumentation Front-Ends
The PIC16C66-10/SP functions as a digital front-end in benchtop instrumentation, processing button inputs, rotary encoders, and LCD drive signals. Its 8-channel A/D acquires sensor signals, while the USART streams readings to a host PC or display processor. The 5 MIPS throughput supports real-time RMS calculation, peak detection, and statistical averaging of measurement data. With 14 KB of OTP program memory, complex calibration curves and lookup tables fit without external storage. The SPDIP package allows easy socket replacement during calibration or firmware validation cycles.
Recommended
Automotive Subsystems (Legacy)
The PIC16C66-10/SP historically powered automotive subsystems such as instrument clusters, HVAC controls, and body controllers where the OTP memory ensured firmware stability against voltage transients and field reprogramming attempts. Its 22 I/O drive stepper motors for gauges, multiplex LED indicators, and read switch matrices. The CCP module handles PWM dimming, while the USART interfaces to body-network ECUs. Note that the commercial temperature grade (0C to +70C) limits automotive use to cabin applications; the PIC16C66-10I/SP industrial variant extends coverage to under-hood environments.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C66-10/SP β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C66-10I/SP | PIC16C65B-20I/P | PIC16C65B-04I/P | PIC16F76-I/SP |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SPDIP (0.300") | 28-SPDIP (0.300") - same | 28-PDIP (0.300") - same footprint | 28-PDIP (0.300") - same footprint | 28-SPDIP (0.300") - same |
| Program Memory | 14 KB OTP | 14 KB OTP | 8 KB OTP (-43%) | 8 KB OTP (-43%) | 14 KB Flash (reprogrammable) |
| Data RAM | 368 bytes | 368 bytes | 192 bytes (-48%) | 192 bytes (-48%) | 368 bytes |
| Maximum Clock | 10 MHz | 10 MHz | 20 MHz (+100%) | 4 MHz (-60%) | 20 MHz (+100%) |
| I/O Pins | 22 | 22 | 33 | 33 | 22 |
| Temperature Grade | Commercial (0C to +70C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) |
| Memory Type | OTP (one-time programmable) | OTP | OTP | OTP | Flash (reprogrammable) |
| Lifecycle Status | NRND | NRND | NRND | NRND | Active |
Key Differentiators
- Higher memory and speed compared to PIC16C65 family (vs PIC16C65B-20I/P)
- Reprogrammable flash memory (vs PIC16F76-I/SP)
- Industrial temperature grade option in same package (vs PIC16C66-10I/SP)
Design Notes
PIC16C66-10/SP uses OTP (one-time programmable) memory. Once programmed, the firmware cannot be erased or modified. Always validate code on a windowed PIC16C66/JW ceramic part or PIC16F76 flash equivalent during development, then commit final firmware to OTP for production. Attempting to reprogram an already-programmed OTP part is not possible - the part must be physically replaced if firmware changes are required.
The PIC16C66-10/SP operates from a single 5V supply on pin 20 (VDD) with ground on pins 8 and 19. Both VSS pins must be connected for proper operation. Place a 100 nF decoupling capacitor as close as possible to the VDD pin, and add a 10 uF bulk capacitor at the board supply entry point. The internal POR (Power-On Reset) and BOR (Brown-Out Reset) circuits require a minimum VDD rise time - ensure the supply ramps monotonically to avoid lockup states.
Oscillator design is critical: connect a 10 MHz crystal between OSC1 (pin 9) and OSC2 (pin 10) with two 15-33 pF load capacitors to VSS. For TTL clock input, drive OSC1 with a 10 MHz square wave and leave OSC2 floating. Keep the oscillator traces short and away from high-current switching nodes to avoid EMI coupling that can cause instruction fetch errors at high frequencies.
ICSP (In-Circuit Serial Programming) requires access to pins 1 (MCLR/VPP), 27 (RB6/PGC), and 28 (RB7/PGD). Reserve a 3-pin header or test points on the PCB for programming, even on production boards, to allow factory programming or field firmware updates during development. Use the standard Microchip ICSP pinout to be compatible with MPLAB ICD programmers.
Port C pins RC6 (TX/CK) and RC7 (RX/DT) double as the USART serial interface. For RS-232 communication, add a MAX232 or equivalent level translator on these pins; for direct TTL/CMOS UART, connect directly to the host with a common ground reference. The USART can be configured for synchronous or asynchronous modes and supports 9-bit addressable multi-drop communications for multi-device RS-485 networks.
Compliance Information
PIC16C66-10/SP is a legacy OTP part originally released before RoHS mandates; current RoHS/REACH compliance status should be verified with Microchip or distributor documentation as of 2026-09-18. Conflict-mineral compliance generally maintained per Microchip policy. AEC-Q100 not applicable for this commercial-grade MCU.
