PIC16C65BT-04/L - 8-Bit 4MHz MCU 7KB OTP 44-PLCC | Microchip
MPN: PIC16C65BT-04/L β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.95 | $7.95 |
| 10 | $7.16 | $71.60 |
| 100 | $6.36 | $636.00 |
| 500 | $5.71 | $2,855.00 |
| 1,000 | $5.07 | $5,070.00 |
PIC16C65BT-04/L Overview
An 8-bit PIC microcontroller is a RISC-class Harvard-architecture device that executes one instruction per cycle (except branches) from on-chip program memory, with separate program and data bus structures. The PIC16CXX family occupies the mid-range tier of Microchip's PIC portfolio (10/12/14/16/17/18-bit instruction widths), positioned above baseline PIC10/12/16 devices and below the high-end PIC17/18 series, and it serves as the ancestor lineage of today's enhanced mid-range PIC16F1xxx family.
Key features of the PIC16C65BT-04/L include 7KB OTP program memory (4K x 14 words), 192 bytes of data RAM, 33 I/O pins, hardware USART for UART, MSSP peripheral supporting SPI and I2C (master/slave), two 8-bit timers plus one 16-bit timer with capture/compare/PWM, a 5-channel 8-bit ADC, and a watchdog timer with on-chip RC oscillator. The CMOS fully-static design permits operation down to DC and supports a wide operating voltage of 2.5V to 5.5V.
The PIC16C65B architecture uses a 14-bit instruction word, two-stage pipeline, 8-level hardware stack, and direct/indirect addressing modes. Its peripheral set is integrated for embedded control, eliminating external logic and reducing BOM cost. Interrupt sources include external RB0/INT, port-B change, timer overflows, USART TX/RX, ADC completion, MSSP, and EEPROM write completion.
Typical applications include industrial control panels, sensor signal conditioning, motor-control front-ends, UART-connected sensor hubs, and legacy embedded systems. The device is widely used in HVAC controls, security alarm panels, vending machine controllers, automotive body electronics, and industrial automation where deterministic 8-bit performance with simple software development is required.
When designing with the PIC16C65BT-04/L, reserve MCLR with a proper RC or diode reset network, place a 0.1uF decoupling capacitor adjacent to each VDD pin, and ensure the oscillator traces are short and guarded by ground. OTP parts cannot be erased, so development should use a windowed PIC16C65B JW part or a Flash equivalent (such as PIC16F877) for prototyping.
This page synthesizes distributor pricing, drop-in alternatives drawn from Microchip's 44-PLCC pin-compatible PIC16C6x family, and practical design considerations not consolidated in the original manufacturer datasheet.
Drop-in alternatives for PIC16C65BT-04/L 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-04/L (same form factor and footprint) β differing in ADC, Mounting Type, Timers, Program Memory Size, CCP Modules.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C65B-04I/L
β Drop-Inβ In Stock
$5.3 / Unit
View Datasheet βPIC16C65B-04E/L
β Drop-Inβ In Stock
$10.85 / Unit
View Datasheet βPIC16C65B-04/PQ
β Drop-Inβ In Stock
$10.25 / Unit
View Datasheet βPIC16F877-04I/L
β Drop-Inπ Reference alternative (not in catalog)
PIC16F874-04I/L
β Drop-Inπ Reference alternative (not in catalog)
PIC16C65A-04I/L
β Drop-Inπ Reference alternative (not in catalog)
PIC16C65BT-04/L Maximum Ratings & Electrical Characteristics
| Core | 8-bit PIC |
| Series | PIC16CXX (PIC16C6x mid-range family) |
| Maximum Clock Frequency | 4 MHz (-04 speed grade) |
| Program Memory Size | 7 KB (4K x 14) OTP |
| RAM Size | 192 x 8 bytes |
| Data EEPROM | Not specified (no internal EEPROM on PIC16C65B) |
| Number of I/O Pins | 33 |
| Package | 44-pin PLCC (J-lead, 16.59 x 16.59 mm) |
| Supply Voltage | 2.5 V to 5.5 V |
| Operating Temperature | -40 C to +85 C (industrial, T-suffix) |
| ADC | 5 channels, 8-bit |
| Timers | Two 8-bit (TMR0, TMR2) + one 16-bit (TMR1) with CCP |
| Communication Peripherals | USART (UART) + MSSP (SPI, I2C master/slave) |
| Watchdog Timer | Yes (with on-chip RC oscillator) |
| Instruction Word Width | 14 bits |
| Mounting Type | Surface Mount (PLCC socket or SMT) |
| Programming Method | OTP (One-Time Programmable, ICSP) |
PIC16C65BT-04/L Pin Configuration
| Pin 1 | RA0/AN0 β Port-A bit 0 / ADC channel 0 |
| Pin 2 | RA1/AN1 β Port-A bit 1 / ADC channel 1 |
| Pin 3 | RA2/AN2 β Port-A bit 2 / ADC channel 2 |
| Pin 4 | RA3/AN3/VREF+ β Port-A bit 3 / ADC channel 3 / ADC reference voltage input |
| Pin 5 | RA4/T0CKI β Port-A bit 4 / Timer-0 external clock input |
| Pin 6 | RA5/AN4/SS β Port-A bit 5 / ADC channel 4 / SPI slave select |
| Pin 7 | OSC1/CLKIN β Oscillator crystal input / external clock input |
| Pin 8 | OSC2/CLKOUT β Oscillator crystal output / clock output (Fosc/4) |
| Pin 9 | MCLR/VPP β Master clear reset (active-low) / programming voltage |
| Pin 10 | VSS β Ground reference |
| Pin 11 | VDD β Positive supply voltage (2.5 V to 5.5 V) |
| Pin 12 | RB0/INT β Port-B bit 0 / external interrupt input |
| Pin 13 | RB1 β Port-B bit 1 |
| Pin 14 | RB2 β Port-B bit 2 |
| Pin 15 | RB3/PGM β Port-B bit 3 / low-voltage ICSP programming clock |
| Pin 16 | RB4 β Port-B bit 4 (interrupt-on-change) |
| Pin 17 | RB5 β Port-B bit 5 (interrupt-on-change) |
| Pin 18 | RB6/PGC β Port-B bit 6 / ICSP serial clock (interrupt-on-change) |
| Pin 19 | RB7/PGD β Port-B bit 7 / ICSP serial data (interrupt-on-change) |
| Pin 20 | RC0/T1OSO/T1CKI β Port-C bit 0 / Timer-1 oscillator output / Timer-1 clock input |
| Pin 21 | RC1/T1OSI/CCP2 β Port-C bit 1 / Timer-1 oscillator input / CCP2 output |
| Pin 22 | RC2/CCP1 β Port-C bit 2 / CCP1 output |
| Pin 23 | RC3/SCK/SCL β Port-C bit 3 / MSSP SPI clock / I2C clock |
| Pin 24 | RC4/SDI/SDA β Port-C bit 4 / MSSP SPI data in / I2C data |
| Pin 25 | RC5/SDO β Port-C bit 5 / MSSP SPI data out |
| Pin 26 | RC6/TX/CK β Port-C bit 6 / USART TX / USART clock |
| Pin 27 | RC7/RX/DT β Port-C bit 7 / USART RX / USART data |
| Pin 28 | RD0 β Port-D bit 0 |
| Pin 29 | RD1 β Port-D bit 1 |
| Pin 30 | RD2 β Port-D bit 2 |
| Pin 31 | RD3 β Port-D bit 3 |
| Pin 32 | RD4 β Port-D bit 4 |
| Pin 33 | RD5 β Port-D bit 5 |
| Pin 34 | RD6 β Port-D bit 6 |
| Pin 35 | RD7 β Port-D bit 7 |
| Pin 36 | RE0/RD β Port-E bit 0 / parallel slave port read |
| Pin 37 | RE1/WR β Port-E bit 1 / parallel slave port write |
| Pin 38 | RE2/CS β Port-E bit 2 / parallel slave port chip select |
| Pin 39 | VSS β Ground reference |
| Pin 40 | VDD β Positive supply 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-04/L is suitable for 6 applications: Industrial Control Panels, HVAC Thermostat Controllers, Security Alarm Panels, Vending Machine Controllers, UART-Connected Sensor Hubs, Automotive Body Electronics.
Industrial Control Panels
The PIC16C65BT-04/L's 33 digital I/O lines, 5-channel 8-bit ADC, and USART fit directly into industrial control panel designs where multiple sensor inputs and actuator outputs must be coordinated. The 4 MHz instruction cycle yields 1 us deterministic timing for PID loop tasks, and the 192-byte RAM accommodates small state machines without external memory. Place the MCU between the 24V-to-5V regulator and the relay/solenoid drivers, with the USART carrying Modbus RTU traffic to a host PLC. Compared with a 16-bit MCU it offers far simpler toolchain and lower BOM cost.
Recommended
HVAC Thermostat Controllers
Wall-mounted HVAC thermostats use the PIC16C65BT-04/L to read thermistor or temperature-sensor ADC channels, drive a triac-gated 24 VAC fan relay, and communicate over UART with a building automation bus. The 4 MHz clock is sufficient for 250 ms control loop and display refresh tasks, and the 33 I/O pins support LCD, keypad, and multiple relay outputs. The 44-PLCC package fits comfortably inside a wall-plate footprint and the -40 to +85 C rating covers plenum environments. Using a Flash sibling like the PIC16F877-I/L avoids OTP write-time delays during calibration.
Recommended
Security Alarm Panels
Alarm panels integrate PIR sensors, door/window reed switches, sirens, and a PSTN or GSM dialer - all of which the PIC16C65BT-04/L can service through its 33 I/O and USART. The MSSP module drives an I2C EEPROM for event logging, while the CCP timer generates precise beep patterns for the piezo siren. The 7 KB OTP program memory accommodates the zone-scan state machine plus dialer firmware. Designed in the late 1990s and still shipped in security panels today, this MCU remains the canonical alarm-panel processor.
Recommended
Vending Machine Controllers
Vending machines require multi-drop coin acceptor interfaces, bill validator pulse counters, dispenser motor drivers, and a multi-button keypad plus LCD display - all roles the PIC16C65BT-04/L handles with its 33 I/O and CCP modules. The MSSP supports SPI to an external shift register that drives the LCD segments, while the USART connects to a MDB peripheral bus. Operating from a 24 VDC bus down-regulated to 5 V, this MCU's 2.5 V to 5.5 V supply range tolerates regulator ripple typical of vending machine power supplies.
Recommended
UART-Connected Sensor Hubs
Distributed sensor hubs aggregate analog and digital inputs from industrial equipment and forward them over RS-485 or RS-232 to a host controller. The PIC16C65BT-04/L's USART supports asynchronous 9-bit mode for RS-485 addressing, while the 5-channel 8-bit ADC handles thermocouple-amplified or pressure-transducer inputs. The MSSP can drive an I2C sensor frontend, freeing the main core to perform protocol framing. With 192 bytes RAM it can buffer a frame before Modbus transmission without external memory.
Recommended
Automotive Body Electronics
Body controllers for window lifters, mirror adjusters, and seat positioners have used the PIC16C65BT-04/L since its introduction, taking advantage of the 33 I/O pins to drive multiple motor H-bridges and read Hall-effect position sensors. The 4 MHz clock generates PWM via the CCP module for soft-start window lifters. Operating from an automotive 12 V bus regulated to 5 V, the MCU must withstand load-dump transients - design with TVS protection and follow Microchip's automotive EMC guidelines. For new automotive programs, migrate to the AEC-Q100 qualified PIC16F877-I/L.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C65BT-04/L β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C65B-04I/L | PIC16C65B-04E/L | PIC16C65B-04/PQ | PIC16F877-04I/L | PIC16F874-04I/L | PIC16C65A-04I/L |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-PLCC (L) | 44-PLCC (L) - same | 44-PLCC (L) - same | 44-PLCC (PQ) - same | 44-PLCC (L) - same | 44-PLCC (L) - same | 44-PLCC (L) - same |
| Program Memory | 7 KB OTP | 7 KB OTP - same | 7 KB OTP - same | 7 KB OTP - same | 14 KB Flash (+100%) | 7 KB Flash (same) | 7 KB OTP - same |
| RAM | 192 B | 192 B - same | 192 B - same | 192 B - same | 368 B (+92%) | 192 B - same | 192 B - same |
| EEPROM | None (OTP) | None - same | None - same | None - same | 256 B internal | 256 B internal | None - same |
| Maximum Clock | 4 MHz | 4 MHz - same | 4 MHz - same | 4 MHz - same | 4 MHz - same | 4 MHz - same | 4 MHz - same |
| I/O Pins | 33 | 33 - same | 33 - same | 33 - same | 33 - same | 33 - same | 33 - same |
| Operating Temperature | -40 C to +85 C (industrial, T-suffix) | -40 C to +85 C (industrial) | -40 C to +125 C (extended) | 0 C to +70 C (commercial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) |
| Lifecycle Status | Obsolete (last-time-buy) | Obsolete | Obsolete | Obsolete | Active | Active | Obsolete |
Key Differentiators
- Silicon revision B silicon for the canonical PIC16C65B mid-range MCU (vs PIC16C65A-04I/L (revision A silicon))
- OTP-based 7 KB program memory for one-time programmable deployment (vs PIC16F877-04I/L (Flash memory))
- Industrial temperature range (-40 C to +85 C) with T-suffix designation (vs PIC16C65B-04/PQ (commercial 0 to +70 C))
Design Notes
Power the PIC16C65BT-04/L from a regulated 5 V (or 3.3 V) supply with at least 100 mA of headroom for I/O switching transients. Place a 0.1 uF decoupling capacitor within 5 mm of each VDD pin (pins 11 and 40) and a bulk 10 uF tantalum or aluminum cap on the supply rail. For battery applications, the brown-out reset (BOR) module must be enabled in the configuration word to prevent code corruption during supply droops below 2.5 V.
PIC16C65B is OTP - firmware is written once and cannot be erased or rewritten. Do not use OTP parts for development; use a JW (windowed) PIC16C65B or a Flash sibling such as PIC16F877 to iterate firmware. Failure to verify your firmware on a Flash equivalent first is a common cause of dead-on-arrival production boards. Always program the configuration word (oscillator, watchdog, BOR, code protection) before the application code to avoid an in-circuit reset loop.
Keep the oscillator traces (OSC1/OSC2) shorter than 10 mm and guard them with a ground pour. Place the 22 pF crystal loading capacitors within 5 mm of the OSC pins with symmetric trace lengths. The MCLR pin must have a 10 kohm pull-up to VDD and a 100 nF cap to ground for decoupling; do not leave MCLR floating or rely on the internal pull-up alone. ICSP pins PGC (RB6) and PGD (RB7) require series 10 kohm resistors near the MCU to isolate the programming tool from the application circuit.
Estimated: at 5 V VDD, 4 MHz clock, and typical I/O loading of 10 mA per pin (33 I/O x 10 mA = 330 mA max), worst-case dissipation is roughly (5 V x 0.330 A) = 1.65 W. The 44-PLCC has theta_JA around 45 C/W on a 1 oz copper 4-layer board, giving a 74 C junction rise above 25 C ambient - within the 125 C max but with margin for elevated ambient. Use wide VDD/VSS copper pours and at least 4 thermal vias under the PLCC die-attach pad to keep junction temperature below 100 C in enclosed industrial enclosures.
Compliance Information
PIC16C65B family is a legacy OTP microcontroller introduced in the late 1990s. RoHS/REACH compliance status is not explicitly documented in the verified data. Lead-free and halogen-free status unknown. Not AEC-Q100 qualified - automotive designs should migrate to PIC16F877-I/L with appropriate automotive qualification. Verification against Microchip product environmental compliance page required.
