PIC16C66T-10I/SO - 8-Bit 10MHz OTP MCU 14KB | Microchip
MPN: PIC16C66T-10I/SO β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.95 | $8.95 |
| 10 | $7.85 | $78.50 |
| 100 | $6.7 | $670.00 |
| 500 | $5.95 | $2,975.00 |
| 1,000 | $5.25 | $5,250.00 |
PIC16C66T-10I/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, and peripheral I/O on one die. The PIC16C6X family belongs to the broader PIC16 mid-range line, sitting in the hierarchy RISC CPU -> 8-bit microcontroller -> embedded controller -> semiconductor. OTP (One-Time Programmable) memory uses EPROM cells that can be programmed once and cannot be erased, positioning this family between mask-ROM (cheapest at volume) and Flash (rewritable) for production runs with stable firmware.
Key features include 22 digital I/O lines arranged across ports A, B and C, three hardware timer modules (Timer0, Timer1 and Timer2), a USART serial port, a synchronous serial port (SSP) supporting SPI and I2C master/slave, a 10-bit multi-channel analog-to-digital converter (ADC), and an internal watchdog timer with on-chip RC oscillator. The device operates from 4.5 V to 5.5 V supply, supports DC to 20 MHz clock input (200 ns instruction cycle), and includes Power-on Reset, Brown-out Reset and Power-Saving Sleep mode.
The architecture is a Harvard-class design with separate program and data buses, a 14-bit wide instruction word, and a deeply pipelined single-cycle ALU. The OTP EPROM cell technology, ceramic-windowed UV-erasable equivalent (PIC16C66 JW), and Microchip's baseline toolchain (MPLAB IDE, MPASM assembler, MPLAB-C compiler) gave this family wide adoption in the 1990s and early 2000s in industrial control, instrumentation and consumer appliances.
Typical applications include motor control (small DC fans, solenoids), industrial instrumentation front-ends, smart-card readers, security and alarm panels, automotive body electronics (non-safety), and consumer appliances requiring deterministic 8-bit control. The 22 I/O pins easily interface keypads, LCD character modules, EEPROM memories, and low-speed sensors.
When designing with this part, ensure Vdd decoupling is placed within 5 mm of the supply pin with at least 0.1 uF ceramic plus 10 uF bulk, and that the MCLR reset pin uses the recommended 10 kohm pull-up plus 100 nF delay network. Because this is an OTP device, firmware must be fully validated in windowed or Flash-equivalent prototypes (PIC16F66 / PIC16C66 JW) before committing to OTP programming for production.
This page synthesizes real distributor inventory, parametric drop-in alternatives, and practical design notes not found in the standalone datasheet PDF.
Drop-in alternatives for PIC16C66T-10I/SO 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 PIC16C66T-10I/SO (same form factor and footprint) β differing in ADC, I/O Pins, Package, Timers, Core Architecture.
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Request AlternativesPIC16C66T-10I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C6X 8-bit RISC (Harvard) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 14 KB (8K x 14 words) |
| Data RAM | 368 bytes |
| Data EEPROM | Not present (external recommended) |
| Maximum Clock Frequency | 20 MHz (200 ns instruction cycle); 10 MHz on this -10 speed grade |
| Instruction Set | 35 single-word instructions, all single-cycle except branches (2-cycle) |
| Supply Voltage (Vdd) | 4.5 V to 5.5 V |
| I/O Pins | 22 (Ports A, B, C) |
| ADC | 10-bit, up to 8 channels |
| Timers | Timer0, Timer1, Timer2 (3 x 8/16-bit) |
| Serial Interfaces | USART (SCI), SSP (SPI / I2C master-slave) |
| Watchdog Timer | Yes, with internal RC oscillator |
| Operating Temperature Range | -40 C to +85 C (Industrial, 'I' suffix) |
| Package | 28-pin SOIC (0.295 in / 7.50 mm width), Tape and Reel |
| Mounting Type | Surface Mount |
PIC16C66T-10I/SO Pin Configuration
| Pin 1 | RA0/AN0 β PORTA bit 0 / ADC input 0 |
| Pin 2 | RA1/AN1 β PORTA bit 1 / ADC input 1 |
| Pin 3 | RA2/AN2 β PORTA bit 2 / ADC input 2 |
| Pin 4 | RA3/AN3/VREF β PORTA bit 3 / ADC input 3 / ADC reference |
| Pin 5 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input |
| Pin 6 | RA5/AN4/SS β PORTA bit 5 / ADC input 4 / SSP slave select |
| Pin 7 | RC0 β PORTC bit 0 |
| Pin 8 | RC1 β PORTC bit 1 |
| Pin 9 | RC2 β PORTC bit 2 |
| Pin 10 | RC3 β PORTC bit 3 |
| Pin 11 | RC4 β PORTC bit 4 |
| Pin 12 | RC5 β PORTC bit 5 |
| Pin 13 | RC6 β PORTC bit 6 |
| Pin 14 | RC7 β PORTC bit 7 |
| Pin 15 | OSC1/CLKIN β Crystal oscillator input / external clock in |
| Pin 16 | OSC2/CLKOUT β Crystal oscillator output / clock out |
| Pin 17 | RB0/INT β PORTB bit 0 / external interrupt |
| Pin 18 | RB1 β PORTB bit 1 |
| Pin 19 | RB2 β PORTB bit 2 |
| Pin 20 | RB3 β PORTB bit 3 |
| Pin 21 | RB4 β PORTB bit 4 |
| Pin 22 | RB5 β PORTB bit 5 |
| Pin 23 | RB6/PGC β PORTB bit 6 / ICSP clock |
| Pin 24 | RB7/PGD β PORTB bit 7 / ICSP data |
| Pin 25 | Vss β Ground reference |
| Pin 26 | VDD β Positive supply voltage (4.5-5.5 V) |
| Pin 27 | RA7 β PORTA bit 7 |
| Pin 28 | RA6 β PORTA bit 6 |
Typical Applications
PIC16C66T-10I/SO is suitable for 7 applications: Industrial Control Front-End, Smart Card Reader Interface, Security and Alarm Panel, Small DC Motor and Fan Controller, Consumer Appliance Control Board, Automotive Body Electronics (Non-Safety), Instrumentation Front-Panel.
Industrial Control Front-End
The PIC16C66T-10I/SO fits industrial control front-ends because of its 22 digital I/O, hardware USART for Modbus-style communication, and 10-bit ADC for sensor conditioning. Its industrial -40 C to +85 C temperature grade suits factory-floor enclosures, while the 4.5-5.5 V supply matches the 5 V backplane common in PLC I/O cards. The 14 KB OTP memory accommodates deterministic control loops with state-machine firmware. With 200 ns single-cycle instructions at 20 MHz input and 400 ns at the 10 MHz rating, scan times for typical 32-channel inputs remain under 100 us. The integrated watchdog timer and brown-out reset provide the fault recovery expected in unattended industrial systems.
Recommended
Smart Card Reader Interface
The PIC16C66T-10I/SO is well suited as the controller in smart card readers because its synchronous serial port (SSP) supports both SPI and I2C, and the USART handles asynchronous communication to the host PC. The 14 KB OTP memory holds the ISO 7816 T=0/T=1 protocol stack with adequate margin for command parsing and ATR handling. The 22 I/O lines drive card presence switches, LEDs, and keypad matrix. Brown-out reset and Power-on Reset ensure clean card-session initialization per EMV specifications. At 10 MHz the instruction budget supports 9600 bps card communication with comfortable headroom for cryptographic preprocessing.
Recommended
Security and Alarm Panel
The PIC16C66T-10I/SO is a natural fit for security alarm panels because the interrupt-on-change feature on PORTB simplifies keypad and PIR sensor monitoring, while the integrated watchdog timer provides the fault detection required by EN 50131 alarm standards. Its 22 I/O can handle a 4x4 keypad, 8-zone sensor input, 4 relay outputs, and a piezo buzzer, with the 10-bit ADC available for battery voltage monitoring. Industrial temperature grade supports garage and basement installations. The 14 KB OTP memory fits ARM-style event-logging firmware with PIN access control, and 368 bytes RAM is adequate for run-time protocol stacks.
Recommended
Small DC Motor and Fan Controller
The PIC16C66T-10I/SO controls small DC motors and fans using its three hardware timers (Timer0, Timer1, Timer2) for PWM generation and tachometer feedback. The 10-bit ADC samples back-EMF or current-sense signals for closed-loop speed regulation. With 22 I/O, the same MCU also drives H-bridge enable lines, brake, and direction logic. Industrial temperature grade suits under-hood automotive and outdoor ventilation applications. The 14 KB OTP holds vector-control or trapezoidal commutation tables. Brown-out reset protects the motor during low-voltage events, while Power-Saving Sleep mode reduces standby current when the motor is idle.
Recommended
Consumer Appliance Control Board
The PIC16C66T-10I/SO is widely deployed in consumer appliance control boards (washing machines, dishwashers, microwave ovens) where its 22 I/O drive 7-segment displays, keypads, relay coils, and triac interfaces. The USART interfaces to inverter boards or sensor expansion modules, while the SSP connects to EEPROM for cycle parameters. Operating from 4.5-5.5 V at 10 MHz gives adequate throughput for user-interface debouncing and PID loops. The 14 KB OTP accommodates appliance firmware with lookup-table-based cycle profiles. Power-on Reset and Brown-out Reset handle brownouts during compressor cycling, a known reliability hazard in motor-driven appliances.
Recommended
Automotive Body Electronics (Non-Safety)
The PIC16C66T-10I/SO serves in automotive body-electronics modules such as seat controllers, mirror adjusters, and lighting sequencers where its 22 I/O directly drive relays and FET gates, and the 10-bit ADC reads position feedback from potentiometers. The -40 C to +85 C industrial grade covers cabin and trunk environments, while optional 'E' extended -40 to +125 C grade addresses under-hood non-safety nodes. The 14 KB OTP holds sequential control algorithms, and the USART interfaces to the body control network. For safety-critical functions, migrate to AEC-Q100 qualified PIC16F family parts; the PIC16C66T-10I/SO is intended for non-safety body convenience modules only.
Recommended
Instrumentation Front-Panel
The PIC16C66T-10I/SO is well suited as the front-panel controller in bench-top test and measurement instruments because its 22 I/O drive 7-segment LED displays, rotary encoders, push-buttons, and status LEDs. The USART links to the main DSP or FPGA for command exchange, while the SSP drives an external DAC or EEPROM calibration memory. The 10-bit ADC is available for monitoring internal rails or thermistor inputs. Industrial temperature grade supports laboratory and factory-floor operation. At 10 MHz with 400 ns instructions, scan loops for 32-key keypads run in under 100 us, well within human-perceptible debounce windows.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C66T-10I/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C66T-10/SO | PIC16C66T-10E/SO | PIC16C66-10I/SO | PIC16F66-I/SO | PIC16C66T-04I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Program Memory Type | OTP EPROM (14 KB) | OTP EPROM (14 KB) | OTP EPROM (14 KB) | OTP EPROM (14 KB) | Flash (14 KB) | OTP EPROM (14 KB) |
| Maximum Clock Speed | 10 MHz | 10 MHz | 10 MHz | 10 MHz | 20 MHz | 4 MHz |
| Operating Temperature | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +125 C (Extended) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
| I/O Pins | 22 | 22 | 22 | 22 | 22 | 22 |
| ADC | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.0 V to 5.5 V | 4.5 V to 5.5 V |
| Packaging Format | Tape & Reel | Tape & Reel | Tape & Reel | Tube | Tube / T&R | Tape & Reel |
Key Differentiators
- Industrial temperature grade in standard 28-SOIC (vs PIC16C66T-10/SO)
- Tape-and-Reel packaging for SMT production (vs PIC16C66-10I/SO)
- Highest tier in legacy PIC16C6X 28-SOIC family (vs PIC16C66T-04I/SO)
- OTP programming model suits mature production (vs PIC16F66-I/SO Flash equivalent)
Design Notes
Place a 0.1 uF ceramic decoupling capacitor within 5 mm of the Vdd pin (pin 26) and a 10 uF bulk tantalum or aluminum on the same supply node. For OTP programming during factory production, Vdd must ramp from 0 V to 5.0 V with a rise time under 1 ms to avoid EPROM cell-stress during power-up brown-out. Estimated: at 10 MHz and 5 V supply, Vdd current draw typically reaches 15-20 mA in active mode and falls below 5 uA in Sleep, so budget the regulator for at least 25 mA continuous.
OTP EPROM cells cannot be erased electrically - any firmware bug becomes permanent after programming. Always validate firmware on the windowed JW variant (PIC16C66-10/JW) or on the Flash PIC16F66-I/SO equivalent before committing to OTP programming for production. A single bad OTP batch can scrap thousands of dollars in parts. Do not exceed Vdd of 5.5 V during programming pulses; the EPROM tunnel oxide degrades with over-voltage and the bit becomes leaky.
Keep the crystal or external clock traces to OSC1 (pin 15) and OSC2 (pin 16) under 10 mm and guard them with a ground pour to avoid radiating clock harmonics into analog ADC inputs. PORTA analog pins should be physically separated from PORTB digital pins on the PCB to reduce digital-to-analog coupling. Place the MCLR pull-up (10 kohm typical) and its 100 nF delay capacitor within 5 mm of pin 4 to guarantee clean reset behavior.
In the 28-SOIC package with plastic thermal pad absent, theta_JA is approximately 80 C/W at still air. At maximum active current of 20 mA at 5 V, dissipation is 100 mW giving a self-heating rise of only 8 C - thermal shutdown will not trigger in normal operation. However, in enclosed industrial housings above 60 C ambient, derate by reducing clock frequency to 4 MHz or by using Sleep mode aggressively. Industrial-grade parts are specified to +85 C ambient with the thermal-rise margin already considered.
Compliance Information
RoHS, REACH, lead-free, halogen-free and conflict-minerals status are not stated in the verified web data; consult Microchip product compliance page or sales contact for confirmation. PIC16C66T-10I/SO is not AEC-Q100 qualified; choose PIC16F66-E/SO or PIC18F family AEC-Q100 parts for automotive safety applications.
