PIC16C66-04E/SP - 8-Bit 4MHz 14KB OTP MCU | Microchip
MPN: PIC16C66-04E/SP β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.95 | $8.95 |
| 10 | $8.06 | $80.60 |
| 100 | $6.88 | $688.00 |
| 500 | $6.05 | $3,025.00 |
| 1,000 | $5.24 | $5,240.00 |
PIC16C66-04E/SP Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, working RAM, and peripherals. Within the broader category, the PIC16C66 sits in the mid-range 8-bit family, hierarchically positioned as: 8-bit MCU -> mid-range MCU -> RISC MCU -> PIC16C family -> PIC16C6x subgroup -> PIC16C66. The /SP suffix designates the SPDIP package, the /04 designator indicates a 4 MHz maximum oscillator frequency, and the E indicates the Extended operating temperature range (-40C to +125C).
Key features include 368 bytes of RAM, 192 bytes of EEPROM data memory, three timers (Timer0, Timer1, Timer2), a 10-bit multi-channel Analog-to-Digital Converter (ADC), a synchronous/asynchronous USART with 9-bit address masking, a Capture/Compare/PWM (CCP) module, and a watchdog timer (WDT) with its own on-chip RC oscillator. Brown-out Reset (BOR) and Power-on Reset (POR) circuitry enhance reliability in noisy supply environments.
The PIC16C66-04E/SP is built on Microchip's low-power, high-speed CMOS EPROM/ROM technology with a fully static design, enabling operation from 2.5V to 6.0V (4.0V to 5.5V for the -04 speed grade) with typical currents of 15 uA at 5V/4 MHz and 1 uA at 3V/32 kHz. Its RISC pipelined core executes most instructions in a single 200 ns cycle, achieving 5 MIPS at 4 MHz.
Typical applications include industrial control systems, automotive subsystems, appliance controllers, sensor interfacing, and low-cost embedded control. The Extended temperature grade and robust peripheral set make it especially suited for harsh-environment deployments.
A critical design consideration is the OTP program memory: once programmed, code cannot be erased. For development work, use a windowed CERDIP version (PIC16C66-04E/JW) or migrate to the Flash-based PIC16F76 in the same 28-pin footprint for production reprogrammability. Always place 100 nF decoupling capacitors close to VDD/VSS pins.
This page synthesizes distributor pricing, drop-in 28-pin SPDIP alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C66-04E/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 PIC16C66-04E/SP (same form factor and footprint) β differing in Core Architecture, Operating Temperature Range, Program Memory Type, Mounting Type, Program Memory Size.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C66-04I/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16C66-04/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16C66-10I/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16C66-20E/SP
β Drop-Inβ In Stock
$4.85 / Unit
View Datasheet βPIC16C67-04E/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16F76-I/SP
β Drop-Inπ Reference alternative (not in catalog)
PIC16C66-04E/SP Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C / 8-bit RISC |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 14 KB (8K x 14) |
| Maximum Clock Frequency | 4 MHz |
| Instruction Set Width | 14-bit |
| RAM Size | 368 bytes |
| EEPROM Data Memory | 192 bytes |
| I/O Pins | 22 |
| Supply Voltage Range | 4.0 V to 5.5 V |
| Operating Temperature Range | -40 C to +125 C (Extended) |
| ADC | 10-bit multi-channel |
| Timers | 3 (Timer0, Timer1, Timer2) |
| Communication | USART (SCI) with 9-bit address masking |
| PWM Channels | 1 (CCP module) |
| Watchdog Timer | Yes (with on-chip RC oscillator) |
| Brown-out Reset / POR | Yes |
| Package | 28-SPDIP (0.300 inch / 7.62 mm) |
| Mounting Type | Through-Hole |
| Instruction Count | 35 single-word instructions |
| Instruction Cycle Time | 200 ns at 4 MHz |
PIC16C66-04E/SP Pin Configuration
| Pin 1 | MCLR/VPP β Master Clear (Reset) input / Programming voltage |
| Pin 2 | RA0/AN0 β PORTA bit 0 / Analog input 0 |
| Pin 3 | RA1/AN1 β PORTA bit 1 / Analog input 1 |
| Pin 4 | RA2/AN2 β PORTA bit 2 / Analog input 2 |
| Pin 5 | RA3/AN3/VREF β PORTA bit 3 / Analog input 3 / ADC reference |
| Pin 6 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS β PORTA bit 5 / Analog input 4 / SPI slave select |
| Pin 8 | OSC1/CLKIN β Oscillator crystal input / external clock in |
| Pin 9 | OSC2/CLKOUT β Oscillator crystal output / clock out |
| Pin 10 | RC0/T1OSO/T1CKI β PORTC bit 0 / Timer1 oscillator out / Timer1 clock in |
| Pin 11 | RC1/T1OSI/CCP2 β PORTC bit 1 / Timer1 oscillator in / CCP2 |
| Pin 12 | RC2/CCP1 β PORTC bit 2 / CCP1 PWM output |
| Pin 13 | RC3/SCK/SCL β PORTC bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA β PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO β PORTC bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK β PORTC bit 6 / USART TX / USART clock |
| Pin 17 | RC7/RX/DT β PORTC bit 7 / USART RX / USART data |
| Pin 18 | VSS β Ground reference |
| Pin 19 | VDD β Positive power supply (4.0 V to 5.5 V) |
| Pin 20 | RB0/INT β PORTB bit 0 / External interrupt |
| Pin 21 | RB1 β PORTB bit 1 |
| Pin 22 | RB2 β PORTB bit 2 |
| Pin 23 | RB3 β PORTB bit 3 |
| Pin 24 | RB4 β PORTB bit 4 |
| Pin 25 | RB5 β PORTB bit 5 |
| Pin 26 | RB6/PGC β PORTB bit 6 / ICSP clock |
| Pin 27 | RB7/PGD β PORTB bit 7 / ICSP data |
| Pin 28 | RE0/RD/AN5 β PORTE bit 0 / Read control / Analog input 5 |
| Pin 29 | RE1/WR/AN6 β PORTE bit 1 / Write control / Analog input 6 |
| Pin 30 | RE2/CS/AN7 β PORTE bit 2 / Chip select / Analog input 7 |
Typical Applications
PIC16C66-04E/SP is suitable for 7 applications: Industrial Sensor Interface and Control, Automotive Subsystem Controllers, Appliance Control Boards, HVAC Climate Control Systems, Smart Card and Secure Access Readers, Low-Cost Data Acquisition and Logging, Power Supply and Battery Charger Controllers.
Industrial Sensor Interface and Control
The PIC16C66-04E/SP is well-suited to industrial sensor interfacing because its 10-bit multi-channel ADC and 22 digital I/O lines handle both analog inputs and discrete control signals in a single IC. With its 4 MHz RISC core delivering 5 MIPS and only 200 ns instruction cycles, the MCU can sample multiple sensors, run a closed-loop PID, and update outputs in real time. The Extended -40 C to +125 C temperature grade supports factory-floor and outdoor installations where commercial parts would fail.
Recommended
Automotive Subsystem Controllers
Automotive body and chassis subsystems such as seat controllers, mirror actuators, lighting modules, and HVAC blend-door actuators are common applications for the PIC16C66-04E/SP. The Extended -40 C to +125 C temperature range covers under-hood and cabin environments, while Brown-out Reset and Power-on Reset protect against automotive supply transients and cranking dropouts. The CCP/PWM module drives actuators directly, and the USART interfaces with body-control LIN or K-line networks via an external transceiver.
Recommended
Appliance Control Boards
White-goods appliance controllers - washing machines, dishwashers, microwave ovens, and refrigerators - frequently use PIC16C66-04E/SP-class MCUs to drive keypads, displays, motor triacs, and sensor inputs. The 14 KB OTP EPROM accommodates sophisticated state machines and user-interface code, while the on-chip EEPROM (192 B) stores calibration constants and user preferences across power cycles. The 28-SPDIP through-hole package is friendly to wave-soldered appliance boards and field replacement.
Recommended
HVAC Climate Control Systems
Heating, ventilation, and air-conditioning (HVAC) climate controllers benefit from the PIC16C66-04E/SP's combination of multi-channel ADC (for temperature and humidity sensors), PWM outputs (for damper and valve actuators), and USART (for thermostat network links). The Extended temperature grade supports attic and outdoor installations, while Brown-out Reset tolerates the brown-outs typical of compressor-driven HVAC supplies. The 5 MIPS throughput easily handles PID climate loops and user-interface tasks.
Recommended
Smart Card and Secure Access Readers
The PIC16C66-04E/SP can serve as the host MCU in low-to-medium-volume secure access readers, where its OTP EPROM protects embedded keys against read-back and its on-chip EEPROM stores user credentials or audit trails. The USART interfaces with external smart-card reader ICs, while the ADC reads tamper sensors. The Extended temperature grade supports outdoor reader housings. Note that for high-security deployments, choose a part with cryptographic hardware acceleration rather than software crypto.
Recommended
Low-Cost Data Acquisition and Logging
Low-cost, multi-channel data-acquisition front-ends with local logging are a natural fit for the PIC16C66-04E/SP. The 10-bit ADC samples up to 8 analog channels, the 192-byte EEPROM offers non-volatile parameter storage, and the USART streams data to a host PC or external memory card. Brown-out Reset protects log integrity against supply glitches. For larger memory, pair with an external I2C EEPROM via the I/O lines; for higher sample rates, step up to the 20 MHz PIC16C66-20E/SP.
Recommended
Power Supply and Battery Charger Controllers
The PIC16C66-04E/SP is used as the supervisory MCU in switch-mode power supplies and battery chargers where its ADC measures voltage and current, its PWM drives a power MOSFET via a gate driver, and its USART communicates with a system host. The on-chip watchdog timer with dedicated RC oscillator catches firmware hangs that could damage batteries or loads. The Extended temperature grade supports outdoor and under-hood charger installations.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C66-04E/SP β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C66-04I/SP | PIC16C66-04/SP | PIC16F76-I/SP |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SPDIP | 28-SPDIP - same | 28-SPDIP - same | 28-SPDIP - same |
| Program Memory | 14 KB OTP EPROM | 14 KB OTP EPROM | 14 KB OTP EPROM | 14 KB Flash |
| Max Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| Operating Temperature | -40 C to +125 C (Extended) | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) |
| RAM | 368 bytes | 368 bytes | 368 bytes | 368 bytes |
| ADC | 10-bit multi-channel | 10-bit multi-channel | 10-bit multi-channel | 10-bit multi-channel (8 channels) |
| Memory Reprogrammability | One-Time Programmable (OTP) | OTP | OTP | Flash (in-circuit reprogrammable) |
| Watchdog Timer | Yes | Yes | Yes | Yes |
Key Differentiators
- Extended temperature grade covers -40 C to +125 C (vs PIC16C66-04I/SP)
- Reprogrammable Flash memory for in-circuit updates (vs PIC16C66-04E/SP (this part))
- Doubles program memory to 16 KB for richer firmware (vs PIC16C67-04E/SP)
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible to the VDD pin (pin 11) and VSS pin (pin 12), with traces kept short to minimize inductance. Add a bulk 10 uF tantalum or aluminum electrolytic capacitor on the VDD rail. For battery-powered designs, the PIC16C66-04E/SP draws approximately 15 uA at 5V/4 MHz and 1 uA at 3V/32 kHz in SLEEP mode, enabling multi-year battery life if wake-up events are infrequent.
The 28-SPDIP package has 0.100 inch (2.54 mm) pin pitch - through-hole friendly for prototype and low-volume production. Keep analog input traces short and away from digital switching signals to avoid ADC noise coupling. Place the crystal (or resonator) close to OSC1 (pin 8) and OSC2 (pin 9), with ground guard traces around the oscillator area. The MCLR pin (pin 1) requires a 10 kohm pull-up to VDD for normal operation.
Do not confuse the PIC16C66-04E/SP (4 MHz, Extended temperature) with the /I (Industrial) or base /SP variants - these have different temperature grades. The OTP EPROM cannot be erased or reprogrammed - once a bit is 0, it stays 0; this makes code revisions impossible in the field. For development, use a windowed CERDIP version (PIC16C66-04E/JW) or migrate to PIC16F76-I/SP for in-circuit reprogrammability. Always configure unused I/O pins as outputs to minimize supply current.
The 10-bit ADC requires adequate acquisition time (typically 20 us for 10k ohm source impedance). Add a small RC filter (100 ohm + 100 nF) on heavily loaded analog inputs to limit bandwidth. Enable the ADC interrupt and read the result in the ADC ISR rather than polling to avoid timing conflicts with PWM or USART peripherals. Use VREF+ tied to VDD only if supply noise is below 1 LSB; otherwise provide a clean external reference.
Compliance Information
RoHS/REACH compliance not explicitly stated in verified web data. The PIC16C66-04E/SP uses OTP EPROM (not Flash), so AEC-Q100 is not commonly qualified for this family; check Microchip automotive-grade product list for PIC16C variants.
