PIC16C66T-04I/SO - 8-Bit 4MHz 14KB EPROM MCU 28-SOIC | Microchip
MPN: PIC16C66T-04I/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.16 | $6.16 |
| 10 | $5.54 | $55.40 |
| 100 | $4.93 | $493.00 |
| 500 | $4.31 | $2,155.00 |
| 1,000 | $3.7 | $3,700.00 |
PIC16C66T-04I/SO Overview
A PIC microcontroller (Programmable Integrated Circuit) is a family of low-cost, high-performance, fully-static 8-bit microcontrollers built on a RISC (Reduced Instruction Set Computing) architecture, in the broader category hierarchy of microcontroller -> embedded processor -> semiconductor IC. The PIC16C6X family uses only 35 single-word instructions to learn, with all instructions executing in a single cycle except program branches (two-cycle), giving a deterministic instruction throughput. The 'C' suffix denotes the original EPROM-based PIC16 family, distinguishing it from later flash-based PIC16F parts.
Key features include 14KB EPROM program memory (8K x 14-bit words), 368 bytes of data RAM, 22 digital I/O pins, integrated synchronous serial port (SSP) supporting SPI and I2C, an addressable USART, three 8-bit timer/counters plus one 16-bit timer/counter with capture/compare/PWM, an 8-bit analog-to-digital converter (ADC) on select family members, and a watchdog timer with on-chip RC oscillator. The 'T' suffix indicates Tape and Reel packaging, while the 'I' suffix indicates the industrial temperature grade of -40C to +85C.
The 28-pin SOIC wide-body (7.50 mm) package is a surface-mount plastic outline with a lead pitch of 1.27 mm, and the device is qualified for industrial operating environments. The PIC16C66T-04I/SO uses a Harvard architecture with separate program and data buses, which allows simultaneous fetch of an instruction and access of a data operand, maximizing throughput at the 4 MHz clock input.
Typical applications include industrial control systems, automotive body and chassis electronics, low-power consumer devices, sensor interface front-ends, and embedded control boards where a small package count and well-documented peripheral set are required. The on-chip peripherals (USART, SSP, timers, ADC) reduce external component count for cost-sensitive designs.
When designing with this part, note that the 4 MHz rating reflects the maximum oscillator input; at this clock most instructions execute in 1 microsecond, and at 5V supply the device typically draws under 20 mA active. Ensure the MCLR reset, oscillator, and power pins are properly decoupled per the Microchip PIC16C6X datasheet to avoid spurious resets or oscillator start-up issues.
This page synthesizes distributor pricing, drop-in and same-family alternatives, and practical design notes not found in a single source on the manufacturer datasheet, helping engineers evaluate and source the PIC16C66T-04I/SO efficiently.
Drop-in alternatives for PIC16C66T-04I/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 PIC16C66T-04I/SO (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, Timers, Number of I/O Pins, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C66-04I/SO
✅ Drop-In✓ In Stock
$5.1 / Unit
View Datasheet →PIC16C66T-04/SO
✅ Drop-In✓ In Stock
$5.5 / Unit
View Datasheet →PIC16C66-20I/SO
✅ Drop-In✓ In Stock
$6.42 / Unit
View Datasheet →PIC16C66-04E/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$5.72 / Unit
View Datasheet →PIC16C66T-04I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C 8-bit RISC |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 14 KB (8K x 14-bit words) |
| Data RAM | 368 bytes |
| Maximum Clock Frequency | 4 MHz |
| Supply Voltage (Vdd) | 4.5 V to 5.5 V |
| Number of I/O Pins | 22 |
| Package Type | 28-SOIC wide-body (7.50 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| Instruction Set | 35 single-word instructions |
| Timers | 3 x 8-bit + 1 x 16-bit with CCP |
| Communication Peripherals | USART, SSP (SPI / I2C) |
| ADC | 8-bit (on family members with ADC suffix) |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| Packaging Suffix | T = Tape & Reel |
| Temperature Grade Suffix | I = Industrial (-40C to +85C) |
PIC16C66T-04I/SO Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / analog input 2 |
| Pin 5 | RA3/AN3/VREF — PORTA bit 3 / analog input 3 / voltage reference |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/SS/AN4 — PORTA bit 5 / slave select / analog input 4 |
| Pin 8 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 9 | OSC2/CLKOUT — Oscillator output |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator out / Timer1 clock in |
| Pin 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator in / CCP2 |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / Capture Compare PWM 1 |
| 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 / clock |
| Pin 17 | RC7/RX/DT — PORTC bit 7 / USART receive / data |
| Pin 18 | VSS — Ground reference |
| Pin 19 | VDD — Positive supply voltage (4.5V to 5.5V) |
| Pin 20 | RB0/INT — PORTB bit 0 / external interrupt |
| Pin 21 | RB1 — PORTB bit 1 |
| Pin 22 | RB2 — PORTB bit 2 |
| Pin 23 | RB3 — PORTB bit 3 |
| Pin 24 | RB4 — PORTB bit 4 |
| Pin 25 | RB5 — PORTB bit 5 |
| Pin 26 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 27 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 28 | VSS — Ground reference (second VSS pin) |
Typical Applications
PIC16C66T-04I/SO is suitable for 6 applications: Industrial Control Systems, Automotive Body Electronics, Consumer Appliance Control, Sensor Interface Front-End, Embedded Control Boards, Low-Power Remote Terminals.
Industrial Control Systems
The PIC16C66T-04I/SO is well matched to industrial control panels where its 22 digital I/O lines, 4 MHz RISC core, and integrated USART and SSP peripherals handle discrete I/O, sensor polling, and serial communication with operator interfaces. The 14KB EPROM stores state machines and lookup tables for PID loops or sequencing, and the 368-byte RAM supports small data buffers without external memory. The industrial -40C to +85C rating allows deployment near motors, solenoids, and 24V control cabinets where ambient temperature swings are routine.
Recommended
Automotive Body Electronics
The PIC16C66T-04I/SO suits automotive body and chassis subsystems such as lighting controllers, mirror positioners, and simple HVAC actuators, where 22 I/O lines interface with relays, switches, and position sensors, and the on-chip USART links to a body control module. The 4 MHz clock delivers 1 microsecond per instruction, sufficient for 10 ms-class control loops; the wide SOIC package and industrial temperature range tolerate under-hood thermal stress. The on-chip ADC and CCP peripherals support throttle position feedback and PWM lamp dimming.
Recommended
Consumer Appliance Control
The PIC16C66T-04I/SO fits cost-sensitive consumer appliances such as washing machine controllers, microwave user interfaces, and small kitchen devices where the 14KB EPROM holds the user interface state machine plus a small protocol stack. The integrated timers drive 7-segment multiplexed displays, the SSP bus interfaces with an EEPROM for user presets, and the USART communicates with inverter boards or sensor modules. The 28-SOIC wide-body package enables single-side PCB assembly in high-volume lines.
Recommended
Sensor Interface Front-End
The PIC16C66T-04I/SO acts as a local sensor front-end for low-bandwidth analog and digital sensors, using the on-chip 8-bit ADC (on ADC-equipped family members) to digitize thermistor, potentiometer, or photodiode signals, and forwarding processed data over USART or SSP to a host processor. The 4 MHz clock and 35-instruction RISC set support simple digital filtering and threshold detection in firmware; the 368-byte RAM is sufficient for circular sample buffers in polled mode.
Recommended
Embedded Control Boards
The PIC16C66T-04I/SO is appropriate for low-cost 8-bit embedded boards such as hobby controllers, evaluation platforms, and training kits, where 22 I/O lines, a USART, and an SSP bus are exposed via 0.1-inch headers. The 14KB EPROM holds the firmware image, the 4 MHz crystal or RC oscillator determines instruction timing, and the MCLR pin supports in-circuit serial programming through the ICSP interface. The 28-SOIC wide-body package is hand-solderable on breakout PCBs for prototyping.
Recommended
Low-Power Remote Terminals
The PIC16C66T-04I/SO supports low-power remote terminal units for utility metering, environmental monitoring, and building automation, where the SLEEP instruction combined with watchdog timer wake-up allows multi-mA average current draw on battery supply. The integrated USART enables low-speed data reporting over RS-485 or radio modem, and the 14KB EPROM stores compressed protocol frames. The industrial temperature grade is essential for outdoor enclosures experiencing seasonal swings.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C66T-04I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C66-04I/SO | PIC16C66T-04/SO | PIC16C66-20I/SO | PIC16C66-04E/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC wide-body (7.50 mm) | 28-SOIC wide-body (7.50 mm) - same | 28-SOIC wide-body (7.50 mm) - same | 28-SOIC wide-body (7.50 mm) - same | 28-SOIC wide-body (7.50 mm) - same |
| Program Memory | 14 KB OTP EPROM | 14 KB OTP EPROM | 14 KB OTP EPROM | 14 KB OTP EPROM | 14 KB OTP EPROM |
| Data RAM | 368 bytes | 368 bytes | 368 bytes | 368 bytes | 368 bytes |
| Max Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 4 MHz |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | -40C to +125C (Extended) |
| Supply Voltage | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V |
| I/O Pins | 22 | 22 | 22 | 22 | 22 |
| Packaging Form | Tape & Reel | Tube | Tape & Reel | Tube | Tube |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND |
Key Differentiators
- Industrial temperature grade and Tape & Reel packaging in a single part number (vs PIC16C66-04I/SO)
- Wider temperature range than commercial grade (vs PIC16C66T-04/SO)
- Lower speed grade for cost-sensitive, time-relaxed designs (vs PIC16C66-20I/SO)
Design Notes
The PIC16C66T-04I/SO operates from a 4.5V to 5.5V single supply. Place a 100 nF decoupling capacitor as close as possible to the VDD pin (pin 19) and another 100 nF near VSS (pin 18) to suppress switching transients from the internal core. For battery-backed or sleep-mode applications, the watchdog timer continues to draw from the watchdog RC oscillator; if the application spends significant time in SLEEP, factor this into the standby budget.
Use a 28-SOIC wide-body land pattern with 1.27 mm pitch. Route the oscillator traces (OSC1/OSC2) short and surrounded by a ground guard ring to reduce radiated emissions and to prevent coupling of high-speed digital signals into the clock. The MCLR pin (pin 1) should be pulled up to VDD through a 10 kohm resistor with a 100 nF capacitor to VSS for brown-out protection; do not leave MCLR floating.
Configuration word programming is required at device programming time to select oscillator mode, watchdog enable, and code protection. Setting the wrong configuration word (especially watchdog always on, or wrong oscillator mode) is a common cause of 'dead' units that appear to be bricked. Verify the configuration bits against the application before programming. Also note: OTP EPROM cannot be erased; design with a flash-based PIC16F equivalent for development cycles and only commit to OTP for production.
Keep the ICSP pins RB6/PGC and RB7/PGD accessible in the PCB layout for in-circuit serial programming, or add a 2x3 or 1x6 header to the board. The 28-SOIC wide-body is hand-solderable but a reflow profile matching JEDEC J-STD-020 (peak 245C for 30 seconds) is recommended for production. Route analog inputs (AN0-AN4) away from high-frequency digital lines to preserve ADC accuracy.
Compliance Information
RoHS, REACH, lead-free, halogen-free, and conflict-minerals status not explicitly provided in verified web data; placeholders marked as unknown. AEC-Q100 is not_applicable because this is a general-purpose industrial/consumer PIC, not specifically qualified to AEC-Q100 automotive standards.
