PIC16C65BT-04I/PT - 8-Bit 4MHz OTP MCU 33 I/O 44-TQFP | Microchip
MPN: PIC16C65BT-04I/PT β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.4 | $640.00 |
| 500 | $5.2 | $2,600.00 |
| 1,000 | $4.1 | $4,100.00 |
PIC16C65BT-04I/PT Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (ROM/Flash/OTP), data memory (RAM), peripherals, and I/O onto one silicon die. The PIC16C mid-range architecture uses a Harvard-style 14-bit instruction word optimized for deterministic, single-cycle execution on most instructions. Microcontrollers sit at the lowest tier of the computing hierarchy above discrete logic, yet below microprocessors, and form the backbone of embedded systems in industrial, automotive, and consumer products.
Key features of the PIC16C65BT-04I/PT include three timer/counter modules, an 8-bit parallel slave port, a watchdog timer with its own on-chip RC oscillator, capture/compare/PWM peripherals, and a power-on reset with brown-out detection. The 33 I/O pins are arranged across multiple ports (PORTA through PORTE) and can source/sink up to 25 mA per pin, allowing direct LED or relay drive in many applications without external transistors.
The OTP program memory means the part is programmed once and cannot be electrically erased, making this MCU family attractive for high-volume, low-cost, fixed-function products where firmware is locked at production. CMOS fully-static design ensures the device holds its state at DC, simplifying low-power sleep-mode implementation. The industrial temperature range and 4 MHz clock rate position this part for deterministic real-time control rather than high-throughput DSP or graphics workloads.
Typical applications include industrial control panels, motor control driver boards, sensor signal conditioning front-ends, HVAC thermostat controllers, and consumer appliance user interfaces. The integrated I2C and SPI peripherals let it act as a master to external EEPROMs, ADCs, DACs, or display drivers without an external bus controller.
When designing with this MCU, verify that the OTP memory size and I/O count are not over-provisioned because OTP parts cannot be firmware-updated in the field; if post-deployment code revision is required, migrate to the flash-based PIC16F877A in the same 44-pin TQFP. Always include decoupling capacitors of 0.1 uF and 10 uF within a few millimeters of the VDD pins and follow the oscillator layout guidelines in the Microchip mid-range reference manual to avoid clock instability.
This page synthesizes current distributor pricing, drop-in alternatives from the PIC16C mid-range family, and practical PCB layout guidance not found in the bare manufacturer datasheet - giving engineers a single-page decision reference for selecting and sourcing this legacy MCU.
Drop-in alternatives for PIC16C65BT-04I/PT 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 PIC16C65BT-04I/PT (same form factor and footprint) β differing in Core Architecture, Operating Temperature, Program Memory Size, Program Memory Type, RAM Size.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C65B-04I/PT
β Drop-Inπ Reference alternative (not in catalog)
PIC16C65B-04I/PQ
β Drop-Inβ In Stock
$5.45 / Unit
View Datasheet βPIC16F877A-I/PT
β Drop-Inπ Reference alternative (not in catalog)
PIC16F877-04I/PT
β Drop-Inπ Reference alternative (not in catalog)
PIC16C65B-20I/PT
β Drop-Inπ Reference alternative (not in catalog)
PIC16C65BT-04I/PT Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Series | PIC16CXX mid-range (PIC16C63A/65B/73B/74B family) |
| Core Architecture | PIC16C CMOS, fully-static, Harvard |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14 bits) |
| RAM Size | 192 x 8 bytes |
| Maximum CPU Frequency | 4 MHz |
| Number of I/O Pins | 33 |
| Supply Voltage (VDD) | 4.0 V to 5.5 V |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Package / Case | 44-TQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Serial Interfaces | I2C, SPI, UART/USART |
| Timers | 3 x Timer/Counters (TMR0, TMR1, TMR2) |
| Peripherals | CCP (Capture/Compare/PWM), WDT, POR/BOR, PSP |
| I/O Sink/Source Current | 25 mA per pin |
| Oscillator Type | External |
| Packaging | Tape & Reel |
| Speed Grade | -04 (4 MHz) |
PIC16C65BT-04I/PT Pin Configuration
| Pin 1 | RA0/AN0 β PORTA bit 0 / analog input 0 |
| Pin 2 | RA1/AN1 β PORTA bit 1 / analog input 1 |
| Pin 3 | RA2/AN2 β PORTA bit 2 / analog input 2 |
| Pin 4 | RA3/AN3/VREF β PORTA bit 3 / analog input 3 / voltage reference |
| Pin 5 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input |
| Pin 6 | RA5/AN4/SS β PORTA bit 5 / analog input 4 / SPI slave select |
| Pin 7 | RE0/RD β PORTE bit 0 / parallel slave port read |
| Pin 8 | RE1/WR β PORTE bit 1 / parallel slave port write |
| Pin 9 | RE2/CS β PORTE bit 2 / parallel slave port chip select |
| Pin 10 | VDD β Positive supply voltage |
| Pin 11 | VSS β Ground reference |
| Pin 12 | OSC1/CLKIN β Oscillator crystal input / external clock in |
| Pin 13 | OSC2/CLKOUT β Oscillator crystal output / clock out |
| Pin 14 | RC0/T1OSO/T1CKI β PORTC bit 0 / Timer1 oscillator output / Timer1 clock |
| Pin 15 | RC1/T1OSI/CCP2 β PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 16 | RC2/CCP1 β PORTC bit 2 / CCP1 PWM output |
| Pin 17 | RC3/SCK/SCL β PORTC bit 3 / SPI clock / I2C clock |
| Pin 18 | RD0/PSP0 β PORTD bit 0 / PSP data bit 0 |
| Pin 19 | RD1/PSP1 β PORTD bit 1 / PSP data bit 1 |
| Pin 20 | RD2/PSP2 β PORTD bit 2 / PSP data bit 2 |
| Pin 21 | RD3/PSP3 β PORTD bit 3 / PSP data bit 3 |
| Pin 22 | RC4/SDI/SDA β PORTC bit 4 / SPI data in / I2C data |
| Pin 23 | RC5/SDO β PORTC bit 5 / SPI data out |
| Pin 24 | RC6/TX/CK β PORTC bit 6 / UART transmit / clock |
| Pin 25 | RC7/RX/DT β PORTC bit 7 / UART receive / data |
| Pin 26 | RD4/PSP4 β PORTD bit 4 / PSP data bit 4 |
| Pin 27 | RD5/PSP5 β PORTD bit 5 / PSP data bit 5 |
| Pin 28 | RD6/PSP6 β PORTD bit 6 / PSP data bit 6 |
| Pin 29 | RD7/PSP7 β PORTD bit 7 / PSP data bit 7 |
| Pin 30 | VSS β Ground reference (second VSS pin) |
| Pin 31 | VDD β Positive supply (second VDD pin) |
| Pin 32 | RB0/INT β PORTB bit 0 / external interrupt |
| Pin 33 | RB1 β PORTB bit 1 |
| Pin 34 | RB2 β PORTB bit 2 |
| Pin 35 | RB3/PGM β PORTB bit 3 / low-voltage programming |
| Pin 36 | RB4 β PORTB bit 4 |
| Pin 37 | RB5 β PORTB bit 5 |
| Pin 38 | RB6/PGC β PORTB bit 6 / ICSP clock |
| Pin 39 | RB7/PGD β PORTB bit 7 / ICSP data |
| Pin 40 | MCLR/VPP β Master clear reset / programming voltage |
| Pin 41 | NC β Not connected (per datasheet) |
| Pin 42 | NC β Not connected (per datasheet) |
| Pin 43 | NC β Not connected (per datasheet) |
| Pin 44 | NC β Not connected (per datasheet) |
Typical Applications
PIC16C65BT-04I/PT is suitable for 7 applications: Industrial Control Panel MCU, HVAC Thermostat Controller, Appliance User Interface Board, Motor Control Driver Board, Sensor Signal Conditioning Front-End, Consumer Electronics Remote Control Receiver, Educational / Legacy Embedded Trainer Board.
Industrial Control Panel MCU
The PIC16C65BT-04I/PT fits industrial control panels because its 33 I/O pins directly drive 7-segment displays, keypads, status LEDs, and relay coils without external transistor arrays - each pin sinks 25 mA. The integrated I2C/SPI peripherals communicate with external EEPROM for parameter storage and DAC chips for analog output, while the 4 MHz core and industrial -40C to +85C temperature range handle factory-floor noise and heat. Three timers enable PWM-driven motor speed control and watchdog-protected deterministic loop timing for fail-safe shutdown.
Recommended
HVAC Thermostat Controller
The PIC16C65BT-04I/PT serves HVAC thermostat controllers by reading temperature sensors over I2C, driving triac-triggered outputs via PWM peripherals, and sequencing multi-stage compressor contactors through its 33 I/O lines. The 4 MHz core executes a 100 ms control loop comfortably, while brown-out reset prevents corrupted EEPROM schedules during power dips. OTP memory locks firmware against field tampering, which is a regulatory plus for commercial HVAC installations requiring fixed control algorithms.
Recommended
Appliance User Interface Board
The PIC16C65BT-04I/PT is well-suited to appliance user-interface boards (washing machines, microwave ovens, dishwashers) where the 33 I/O lines scan matrix keypads and drive 7-segment or character LCD displays. Its 192 bytes of SRAM buffer key-press debounce state, while the UART links to the main appliance controller for diagnostics. OTP memory locks the production firmware version permanently, eliminating field misconfiguration risk; the 4.0-5.5 V supply matches the appliance's 5 V regulator rail directly.
Recommended
Motor Control Driver Board
The PIC16C65BT-04I/PT controls small brushed DC and stepper motors via its CCP (Capture/Compare/PWM) module generating variable duty-cycle drive signals to external H-bridge MOSFET drivers. The 4 MHz clock yields a 1 us instruction cycle, fine enough for 10 kHz PWM switching without CPU overhead. Quadrature encoder feedback from motor shafts enters through the timer/counter capture inputs, while the watchdog timer enforces a fail-safe stop if the control loop stalls. The 44-TQFP package gives adequate thermal margin for 25 mA I/O switching.
Recommended
Sensor Signal Conditioning Front-End
The PIC16C65BT-04I/PT acts as a sensor front-end controller in industrial measurement systems, reading multiple analog sensors through an external ADC over SPI while controlling excitation and multiplexing with its GPIO. The MSSP module runs SPI at up to 4 MHz for fast successive-approximation ADC reads, while the UART streams calibrated data to a host PLC. OTP memory locks calibration coefficients against unauthorized change, important in regulated metrology applications.
Recommended
Consumer Electronics Remote Control Receiver
The PIC16C65BT-04I/PT decodes IR remote protocols in consumer AV equipment, capturing pulse widths via the CCP module and running the protocol state machine on its 4 MHz core. Its low power consumption in sleep mode (watchdog timer active) suits always-on receiver applications, while the 192-byte SRAM buffer holds incoming command streams. OTP memory ensures the decoding algorithm cannot be field-modified, protecting against unauthorized control-plane tampering in pay-TV set-top boxes.
Recommended
Educational / Legacy Embedded Trainer Board
The PIC16C65BT-04I/PT is widely used in university embedded systems courses and legacy training boards because the 44-TQFP gives access to every peripheral (I2C, SPI, UART, PWM, PSP) in a single chip without external glue logic. The 7 KB OTP forces students to write efficient assembly or C code within a tight memory budget, building skills still applicable to modern flash PICs. The 33 I/O lines drive breadboard LEDs, switches, and character displays typical of course labs.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C65BT-04I/PT β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C65B-04I/PT | PIC16F877A-I/PT | PIC16C65B-20I/PT |
|---|---|---|---|---|
| Package | 44-TQFP (10x10) | 44-TQFP (10x10) - same | 44-TQFP (10x10) - same | 44-TQFP (10x10) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 7 KB OTP | 7 KB OTP | 14 KB Flash | 7 KB OTP |
| RAM Size | 192 B | 192 B | 368 B | 192 B |
| Maximum Frequency | 4 MHz | 4 MHz | 20 MHz | 20 MHz |
| Number of I/O | 33 | 33 | 33 | 33 |
| Lifecycle Status | Obsolete | Obsolete | Active | Obsolete |
| Memory Type | OTP | OTP | Flash (re-programmable) | OTP |
Key Differentiators
- Tray-pack variant of identical silicon (vs PIC16C65B-04I/PT)
- Drop-in upgrade path to flash memory (vs PIC16F877A-I/PT)
- Five-times faster clock headroom (vs PIC16C65B-20I/PT)
Design Notes
Place a 0.1 uF ceramic decoupling capacitor within 5 mm of every VDD pin (pins 10 and 31 on the 44-TQFP) and a bulk 10 uF electrolytic or tantalum capacitor on the 5 V supply rail near the MCU. The PIC16C65BT-04I/PT draws approximately 5-15 mA active depending on oscillator configuration and I/O loading. If using sleep mode, the brown-out reset (BOR) must remain enabled to prevent corrupted EEPROM reads on power-up.
Route the OSC1/OSC2 traces (pins 12 and 13) as short as possible, surrounded by a ground guard ring, and keep them away from high-current switching traces to avoid clock jitter. If using a crystal, place the load capacitors (typically 15-33 pF) within 2 mm of the oscillator pins. The MCLR pin (pin 40) requires a 10 kohm pull-up to VDD and a 100 nF capacitor to ground for proper reset behavior - do not leave it floating.
Because the PIC16C65BT-04I/PT uses OTP memory, firmware bugs cannot be patched in the field - any silicon revision requires a board swap. Designers must invest in thorough firmware QA and pre-production burn-in testing. Also note that the -04 speed grade specifies a 4 MHz maximum oscillator input; using an 8 MHz or 20 MHz crystal will cause timing failures. If higher throughput is needed, choose the PIC16C65B-20I/PT or PIC16F877A-I/PT instead.
The PORTB pins (RB0-RB7) have internal weak pull-ups that can be enabled via the RBPU bit in the OPTION register - useful for keypad scanning without external resistors. However, PORTD used as the parallel slave port (PSP) does not have internal pull-ups and may require external 10 kohm pull-ups if interfacing with a host that tri-states its data lines during bus release. The 25 mA sink/source rating per pin allows direct LED drive but mandates series current-limit resistors to prevent destruction.
Compliance Information
Obsolete Microchip MCU; pre-dates full RoHS conversion so lead-bearing finish is typical. The pin-compatible flash replacement PIC16F877A-I/PT is RoHS compliant. REACH, halogen-free status not explicitly documented in the verified data for this legacy part.