PIC16C65AT-04I/L - 8-Bit OTP MCU 7KB 4MHz PLCC-44 | Microchip
MPN: PIC16C65AT-04I/L ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.95 | $9.95 |
| 10 | $9.1 | $91.00 |
| 100 | $8.2 | $820.00 |
| 500 | $7.35 | $3,675.00 |
| 1,000 | $6.6 | $6,600.00 |
PIC16C65AT-04I/L Overview
What is an OTP PIC microcontroller? An OTP (One-Time Programmable) microcontroller uses EPROM-based program memory that can be written only once and then retains the code permanently without a backup battery. Within the broader taxonomy it sits as: microcontroller -> embedded MCU -> 8-bit MCU -> PIC16 family -> PIC16C6X sub-family. The PIC16C65A was the original CMOS EPROM member of the PIC16C6X line, providing RISC performance for embedded industrial designs of the 1990s and early 2000s.
Key features highlighted by the verified distributor data include 33 digital I/O lines, an external oscillator interface, an internal 8-bit timer/counter architecture and synchronous/asynchronous serial port (USART/SCI) capability per the PIC16C6X family specification. The PLCC-44 (16.59 x 16.59 mm, J-lead) format gives robust socket compatibility for legacy through-hole industrial and test-fixture designs where DIP-40 or PLCC-44 sockets are already deployed. The /L suffix indicates the J-lead PLCC-44 package form.
From a technical-depth perspective, the PIC16C65A uses a Harvard-architecture RISC core with separate program and data buses, allowing instruction fetch and data access to occur in parallel. The 14-bit instruction word supports direct, indirect, and relative addressing modes, and the architecture provides hardware stack for subroutine nesting. Power-saving modes include the SLEEP state, and a watchdog timer is available to recover from software lockups in unattended equipment.
Typical applications are industrial automation controllers, instrumentation front-ends, motor-control auxiliary logic, embedded sensor hubs, automotive aftermarket modules, and legacy equipment service replacements where a socketed PLCC-44 PIC must be substituted. Many design teams keep PIC16C65A stock on hand to maintain older field installations.
Design consideration: because the device is OTP, code must be fully verified before programming — there is no in-system reprogram path. For new designs the PIC16F877A (Flash-based) is the modern recommended migration, while the PLCC-44 socket footprint keeps PIC16C65AT-04I/L a true drop-in for legacy boards.
This page combines distributor pricing, verified PIC16C65A family specs, drop-in alternatives, and practical design notes not consolidated in any single manufacturer document.
Drop-in alternatives for PIC16C65AT-04I/L — 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 PIC16C65AT-04I/L (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, Mounting Type, Core Architecture, Maximum Clock Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C65A-04I/L
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C65AT-04E/L
✅ Drop-In✓ In Stock
$5.75 / Unit
View Datasheet →PIC16C65A-04E/L
✅ Drop-In✓ In Stock
$11.2 / Unit
View Datasheet →PIC16C65A-04/L
✅ Drop-In✓ In Stock
$9.2 / Unit
View Datasheet →PIC16C65BT-04E/L
✅ Drop-In✓ In Stock
$7.1 / Unit
View Datasheet →PIC16C65AT-04I/L Maximum Ratings & Electrical Characteristics
| Core | PIC16 8-bit RISC |
| Series | PIC16C6X (PIC16C65A) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 192 x 8 bytes |
| CPU Speed | 4 MHz |
| Supply Voltage | 5 V |
| Number of I/O | 33 |
| Package | 44-pin PLCC (J-Lead), 16.59 x 16.59 mm |
| Oscillator Type | External |
| Operating Temperature Grade | Industrial (-40C to +85C) |
| Packaging | Tape & Reel (TR) |
| Mounting Type | Surface Mount |
| RoHS Status | unknown (legacy EPROM part, often non-RoHS) |
| Lead-Free | unknown |
| Instruction Word Width | 14 bits |
| Instruction Set | 35 single-word instructions |
| Data EEPROM | None (OTP program memory only) |
| Number of Terminals | 44 |
| Terminal Form | J-BEND |
| Package Code | QCCJ |
PIC16C65AT-04I/L Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| Pin 3 | RA2/AN2/VREF- — PORTA bit 2 / Analog input 2 / Negative voltage reference |
| Pin 4 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input 3 / Positive voltage reference |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input (open-drain) |
| Pin 6 | RA5/SS/AN4 — PORTA bit 5 / Slave Select for SPI / Analog input 4 |
| Pin 7 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 8 | OSC2/CLKOUT — Oscillator crystal output / clock out (Fosc/4) |
| Pin 9 | MCLR — Master Clear reset input (active low) |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply (5V nominal) |
| Pin 12 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 13 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / Capture/Compare/PWM 2 |
| Pin 14 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM 1 |
| Pin 15 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 16 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 17 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 18 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 19 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply (5V nominal) |
| Pin 22 | RB0/INT — PORTB bit 0 / External interrupt input |
| Pin 23 | RB1 — PORTB bit 1 |
| Pin 24 | RB2 — PORTB bit 2 |
| Pin 25 | RB3 — PORTB bit 3 |
| Pin 26 | RB4 — PORTB bit 4 |
| Pin 27 | RB5 — PORTB bit 5 |
| Pin 28 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 29 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply (5V nominal) |
| Pin 32 | RD0 — PORTD bit 0 |
| Pin 33 | RD1 — PORTD bit 1 |
| Pin 34 | RD2 — PORTD bit 2 |
| Pin 35 | RD3 — PORTD bit 3 |
| Pin 36 | RD4 — PORTD bit 4 |
| Pin 37 | RD5 — PORTD bit 5 |
| Pin 38 | RD6 — PORTD bit 6 |
| Pin 39 | RD7 — PORTD bit 7 |
| Pin 40 | VSS — Ground reference |
| Pin 41 | VDD — Positive supply (5V nominal) |
| Pin 42 | RE0/RD — PORTE bit 0 / Read control for parallel slave port |
| Pin 43 | RE1/WR — PORTE bit 1 / Write control for parallel slave port |
| Pin 44 | RE2/CS — PORTE bit 2 / Chip select for parallel slave port |
Typical Applications
PIC16C65AT-04I/L is suitable for 7 applications: Industrial Automation Controllers, Legacy Test & Measurement Instrumentation, Automotive Aftermarket Modules, Embedded Sensor Hubs, Motor Control Auxiliary Logic, Service Replacement Stock for Obsolete Designs, Educational and Training Platforms.
Industrial Automation Controllers
The PIC16C65AT-04I/L's 7 KB OTP program memory and 33 digital I/O lines suit industrial PLC-style controllers where deterministic RISC execution and socketed PLCC-44 maintenance are valued. Its -40C to +85C industrial temperature grade ensures reliable operation in factory-floor enclosures. The 4 MHz clock drives 35 single-word instructions in a single cycle, providing predictable loop timing for relay, solenoid, and sensor I/O control. Engineers use it to manage conveyor logic, machine-tool interlocks, and process-control sub-systems where long-term firmware stability outweighs the need for in-field reprogramming.
Recommended
Legacy Test & Measurement Instrumentation
Test equipment manufacturers built thousands of instruments around the PIC16C65A OTP microcontroller in the late 1990s, and many of those instruments remain in service today. The PIC16C65AT-04I/L drops directly into the original PLCC-44 socket, restoring functionality without PCB redesign. Its 192 bytes of RAM and 7 KB code space support calibration routines, range-switching logic, and front-panel button-matrix scanning. Service technicians keep this part on hand because the OTP memory preserves calibration constants and avoids accidental firmware tampering during repair.
Recommended
Automotive Aftermarket Modules
Automotive aftermarket products (alarm systems, engine tuners, gauge drivers, and lighting controllers) frequently used the PIC16C65AT-04I/L for its robust I/O count and industrial temperature grade. The 33 I/O pins interface with switches, relays, LEDs, and CAN/LIN transceivers in older vehicles. While not AEC-Q100 qualified (it predates that standard for this part), the -40C to +85C range covers under-dash and engine-bay conditions with adequate thermal margin. The OTP memory prevents inadvertent code modification in harsh environments.
Recommended
Embedded Sensor Hubs
The PIC16C65AT-04I/L is well-matched to sensor-hub nodes aggregating thermocouple, strain-gauge, or 4-20 mA inputs in industrial networks. Its USART/SCI peripheral enables RS-232 or RS-485 networking back to a master controller, while 33 I/O lines drive multiplexer select lines and signal-conditioning switches. The 7 KB code space accommodates linearization tables for thermocouples and RTDs. Designers appreciate the deterministic interrupt response and the absence of operating-system overhead in such embedded sensor nodes.
Recommended
Motor Control Auxiliary Logic
Stepper, BLDC, and DC-motor controllers use the PIC16C65AT-04I/L as auxiliary logic for direction, enable, fault detection, and communication, while a dedicated motor-driver IC handles the power stage. The PIC's 4 MHz CPU and single-cycle instruction execution deliver tight timing for quadrature decoding and PWM generation in supervisory loops. The OTP memory locks down safety-related firmware so it cannot be tampered with. Industrial temperature operation ensures reliability in motor enclosures.
Recommended
Service Replacement Stock for Obsolete Designs
Many OEMs and contract manufacturers maintain safety stock of the PIC16C65AT-04I/L specifically to support field-installed equipment that must remain operational for 15-20 year service lifetimes. The OTP nature guarantees firmware integrity over decades, and the PLCC-44 socket allows quick field swap without desoldering. Brokers and franchised distributors still carry inventory of this part, and the part is widely listed on Octopart, DigiKey, and Mouser legacy catalogues. For new designs, engineers should migrate to PIC16F877A-I/L, but for service stock this is the canonical part.
Recommended
Educational and Training Platforms
Universities and technical colleges continue to use the PIC16C65AT-04I/L in embedded-systems curricula because the PLCC-44 socket allows students to repeatedly insert and remove the part during lab exercises without PCB wear. The 7 KB code space, 35-instruction RISC core, and 33 I/O pins offer a tractable platform for teaching assembly language, timer/counter programming, and interrupt-driven design. The OTP memory teaches students the discipline of single-shot programming and firmware validation before commit.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C65AT-04I/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C65A-04I/L | PIC16C65AT-04E/L | PIC16C65A-04E/L | PIC16C65A-04/L | PIC16C65BT-04E/L |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-PLCC (J-Lead) | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same | 44-PLCC (J-Lead) - same |
| Program Memory | 7 KB OTP (4K x 14) | 7 KB OTP (4K x 14) | 7 KB OTP (4K x 14) | 7 KB OTP (4K x 14) | 7 KB OTP (4K x 14) | 7 KB OTP (4K x 14) |
| RAM | 192 x 8 bytes | 192 x 8 bytes | 192 x 8 bytes | 192 x 8 bytes | 192 x 8 bytes | 192 x 8 bytes |
| CPU Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Temperature Grade | Industrial -40C to +85C | Industrial -40C to +85C | Extended -40C to +125C | Extended -40C to +125C | Commercial 0C to +70C | Extended -40C to +125C |
| Number of I/O | 33 | 33 | 33 | 33 | 33 | 33 |
| Silicon Revision | PIC16C65A (rev A) | PIC16C65A (rev A) | PIC16C65A (rev A) | PIC16C65A (rev A) | PIC16C65A (rev A) | PIC16C65B (rev B) |
| Packaging Format | Tape & Reel (TR) | Tube | Tape & Reel | Tube | Tube | Tape & Reel |
Key Differentiators
- Tape & Reel format optimized for high-volume SMT assembly (vs PIC16C65A-04I/L)
- Industrial temperature range covering factory-floor environments (vs PIC16C65A-04/L)
- Wide authorized distributor availability for legacy support (vs PIC16C65BT-04E/L)
Design Notes
PIC16C65AT-04I/L operates from a single 5V supply. Place a 100 nF decoupling capacitor within 5 mm of each VDD pin (pins 11, 21, 31, 41) and a bulk 10 uF tantalum or aluminum electrolytic capacitor at the board's power-entry point. The PIC16C6X family datasheet recommends keeping VDD rise time below a few milliseconds to ensure proper Power-On Reset; an RC delay on MCLR or a reset supervisor IC may be needed in slow-ramp supplies. All four VDD pins must be connected, and all four VSS pins must be tied to ground.
Because the PIC16C65AT-04I/L is OTP (one-time programmable), every firmware build burned into a part is permanent. Design teams must validate code in a windowed EPROM emulator (e.g. PIC16C65A with JW package) or in-circuit emulation (ICE 2000) before committing production units. Never use production OTP parts for engineering bring-up. A common pitfall is burning configuration bits (watchdog, oscillator, code protect) incorrectly, which can lock the engineer out of the device — always double-check CONFIG word settings before programming.
Place the 4 MHz crystal or ceramic resonator as close as possible to OSC1 (pin 7) and OSC2 (pin 8), with short traces and a ground pour underneath. Add 22-33 pF loading capacitors (C1, C2) from each oscillator pin to ground. Keep high-frequency digital traces (PORTD bus, USART lines) away from the oscillator loop. The PLCC-44 socket should be a low-profile machined-pin type with gold-plated contacts for reliable insertion cycles in service-replacement scenarios.
Compliance Information
PIC16C65AT-04I/L is a legacy OTP EPROM part from the 1990s; explicit RoHS, REACH and halogen-free declarations were not in the verified web data. The PIC16C6X family is generally not AEC-Q100 qualified, so this part is not recommended for safety-critical automotive applications. Verify compliance with the Microchip product page or PCN documents before designing in for new programs.