PIC16C65A-04I/PQ - 4MHz 8-bit MCU, 7KB OTP, 44-MQFP | Microchip
MPN: PIC16C65A-04I/PQ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $15.55 | $15.55 |
| 10 | $14.2 | $142.00 |
| 100 | $12.85 | $1,285.00 |
| 500 | $11.4 | $5,700.00 |
| 1,000 | $9.95 | $9,950.00 |
PIC16C65A-04I/PQ Overview
What is an 8-bit OTP microcontroller? An 8-bit microcontroller integrates a CPU, program memory, RAM, and peripherals on a single die. OTP (One-Time-Programmable) memory uses EPROM cells that can be written once and erased only by UV exposure (through a windowed package). In the broader taxonomy, the PIC16C65A sits under microcontroller -> embedded MCU -> semiconductor device, and it belongs to Microchip's mid-range PIC16 family that uses a 14-bit instruction word.
Key features include a high-performance RISC CPU with only 35 single-word instructions, all single-cycle except program branches (two cycles), and DC to 4 MHz operating speed. Power consumption is low at 5V/4 MHz (15 uA typical) and 3V/32 kHz (1 uA typical). The PIC16C65A integrates multiple peripherals: a USART for serial communication, an SSP module for SPI/I2C, capture/compare/PWM (CCP) modules, an 8-bit ADC, and two 8-bit timers plus one 16-bit timer with optional prescaler.
The architecture uses a Harvard design with separate program and data buses, allowing instruction fetch and data access in a single clock cycle. This RISC-style approach delivers deterministic execution and predictable interrupt latency, which has made the PIC16 mid-range family a workhorse for industrial control and embedded applications since the 1990s. The 44-MQFP package provides 33 I/O pins - more than smaller PIC16C6X parts (28-pin) - while remaining compatible with the same instruction set and development toolchain.
Typical applications include industrial automation controllers, sensor signal conditioning, motor control with PWM, serial communication bridges, embedded data acquisition, and legacy embedded-system upgrades. The wide industrial temperature range and OTP memory suit fixed-program production runs where field firmware updates are not required.
Design tip: when migrating from the PIC16C65B or PIC16C65 to PIC16C65A, verify peripheral register maps; the 'A' revision changed ADC configuration bits. For modern designs, consider the flash-based PIC16F877A as a drop-in upgrade with the same 44-pin footprint but in-circuit reprogrammability.
This page synthesizes distributor pricing, drop-in alternatives, and engineering design notes not typically presented in a single manufacturer datasheet view.
Drop-in alternatives for PIC16C65A-04I/PQ — 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 PIC16C65A-04I/PQ (same form factor and footprint) — differing in Operating Temperature Range, Package, Timers, Program Memory Size, Instruction Set.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C65A-04I/P
✅ Drop-In✓ In Stock
$5.25 / Unit
View Datasheet →PIC16C65A-04/PQ
✅ Drop-In✓ In Stock
$6.2 / Unit
View Datasheet →PIC16F877A-I/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C64A-04I/PQ
✅ Drop-In✓ In Stock
$6.4 / Unit
View Datasheet →PIC16C64AT-04I/PQ
✅ Drop-In✓ In Stock
$7.55 / Unit
View Datasheet →PIC16C65A-04I/PQ Maximum Ratings & Electrical Characteristics
| Product Family | PIC16C6X Mid-Range |
| Core Architecture | 8-bit RISC (PIC16) |
| Program Memory | 7 KB (4K x 14) OTP EPROM |
| RAM | 192 bytes |
| EEPROM Data Memory | None (OTP only) |
| Maximum Clock Frequency | 4 MHz |
| Instruction Set Size | 35 single-word instructions |
| Operating Voltage (Vdd) | 4.0 V to 5.5 V |
| I/O Pins | 33 |
| Timers | Two 8-bit, one 16-bit |
| ADC | 8-bit, 8 channels |
| Serial Communication | USART (SCI), SSP (SPI/I2C) |
| CCP Modules | Yes (Capture/Compare/PWM) |
| Interrupt Sources | Yes (multiple vectored) |
| Package | 44-pin MQFP (10x10 mm), gull-wing |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Power Consumption (5V/4 MHz) | 15 uA typical |
| Power Consumption (3V/32 kHz) | 1 uA typical |
| Programming Method | Parallel (OTP EPROM, UV-erasable window optional) |
PIC16C65A-04I/PQ Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / Analog input 2 |
| Pin 4 | RA3/AN3 — PORTA bit 3 / Analog input 3 |
| Pin 5 | RA4/AN4 — PORTA bit 4 / Analog input 4 (open-drain) |
| Pin 6 | RA5/AN5/SS — PORTA bit 5 / Analog input 5 / SPI Slave Select |
| Pin 7 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 8 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| Pin 9 | MCLR — Master Clear reset input (active low) |
| Pin 10 | Vss — Ground reference |
| Pin 11 | RC0 — PORTC bit 0 |
| Pin 12 | RC1 — PORTC bit 1 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / Capture-Compare-PWM 1 output |
| Pin 14 | RC3 — PORTC bit 3 |
| Pin 15 | RC4 — PORTC bit 4 |
| Pin 16 | RC5 — PORTC bit 5 |
| Pin 17 | RC6/Tx/CK — PORTC bit 6 / USART Tx / I2C clock |
| Pin 18 | RC7/Rx/DT — PORTC bit 7 / USART Rx / I2C data |
| Pin 19 | Vss — Ground reference |
| Pin 20 | VDD — Positive supply voltage (4.0V to 5.5V) |
| Pin 21 | RD0 — PORTD bit 0 |
| Pin 22 | RD1 — PORTD bit 1 |
| Pin 23 | RD2 — PORTD bit 2 |
| Pin 24 | RD3 — PORTD bit 3 |
| Pin 25 | RD4 — PORTD bit 4 |
| Pin 26 | RD5 — PORTD bit 5 |
| Pin 27 | RD6 — PORTD bit 6 |
| Pin 28 | RD7 — PORTD bit 7 |
| Pin 29 | RE0/RD — PORTE bit 0 / Parallel Slave Port read |
| Pin 30 | RE1/WR — PORTE bit 1 / Parallel Slave Port write |
| Pin 31 | RE2/CS — PORTE bit 2 / Parallel Slave Port chip select |
| Pin 32 | Vss — Ground reference |
| Pin 33 | VDD — Positive supply voltage |
| Pin 34 | RB0/INT — PORTB bit 0 / External interrupt input |
| Pin 35 | RB1 — PORTB bit 1 |
| Pin 36 | RB2 — PORTB bit 2 |
| Pin 37 | RB3 — PORTB bit 3 |
| Pin 38 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 39 | RB5 — PORTB bit 5 (interrupt-on-change) |
| Pin 40 | RB6 — PORTB bit 6 (interrupt-on-change / ICSP clock) |
| Pin 41 | RB7 — PORTB bit 7 (interrupt-on-change / ICSP data) |
| Pin 42 | Vss — Ground reference |
| Pin 43 | VDD — Positive supply voltage |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C65A-04I/PQ is suitable for 6 applications: Industrial Automation Controllers, Sensor Signal Conditioning & Data Acquisition, Motor Control with PWM (CCP), Serial Communication Bridges (UART/SPI/I2C), Embedded Display & Keypad Interfaces, Legacy Embedded System Upgrades.
Industrial Automation Controllers
The PIC16C65A-04I/PQ fits industrial automation controllers because of its industrial -40 C to +85 C temperature range, 33 digital I/O pins for digital inputs and relay outputs, USART for Modbus RTU slave communication, and 8-channel 8-bit ADC for analog sensor acquisition (pressure, temperature, flow). Its 7 KB OTP memory holds mid-complexity ladder-replacement firmware for PLC block I/O and machine control. The 44-MQFP footprint gives enough I/O to drive multi-axis systems or 16+ opto-isolated digital inputs directly. Long-term Microchip lifecycle support and stable silicon make it a low-risk choice for production industrial equipment where firmware is locked after release. Power consumption of 15 uA at 5V/4 MHz allows fan-less DIN-rail enclosures.
Recommended
Sensor Signal Conditioning & Data Acquisition
The PIC16C65A-04I/PQ is a strong fit for sensor signal conditioning front-ends thanks to its 8-channel 8-bit ADC, multiple timers for sampling rate control, and USART/SPI interfaces for forwarding digitized data to a host controller or display. The ADC has 8 input channels shared with PORTA, sufficient for thermocouple, RTD bridge, pressure transducer, and photo-sensor arrays. USART enables RS-232/RS-485 output to SCADA or HMI panels. At 4 MHz instruction rate, the MCU can sustain ~30 ksps with proper ADC clock prescaler selection. The PIC16 mid-range core's deterministic 1 us instruction cycle simplifies real-time sampling loop design. Industrial temperature grade supports outdoor and process-plant deployment.
Recommended
Motor Control with PWM (CCP)
The PIC16C65A-04I/PQ's two Capture/Compare/PWM modules and 16-bit TMR1 make it suitable for brushed DC motor speed control and stepper motor sequencing. The CCP PWM outputs drive MOSFET gate drivers at frequencies up to ~20 kHz (above audible range for quiet operation), while TMR1 provides precise commutation timing. 33 I/O pins can support up to 4 half-bridge motor channels or a single 3-phase bridge with logic-level FET drivers. Quadrature encoder feedback uses the CCP capture input. The 7 KB OTP holds PID loop firmware plus safety state machines. Industrial temperature grade supports factory-floor motor cabinets. For higher-performance BLDC/FOC control, migrate to dsPIC30F or PIC16F877A variants.
Recommended
Serial Communication Bridges (UART/SPI/I2C)
The PIC16C65A-04I/PQ excels as a protocol bridge between UART, SPI, and I2C devices. Its integrated USART (SCI) provides asynchronous RS-232/RS-485 communication, while the SSP module supports both SPI master/slave and I2C slave modes. This allows the MCU to act as a gateway between legacy UART peripherals and modern SPI/I2C sensors, or as a Modbus-to-I2C adapter for industrial networks. At 4 MHz, sustained SPI throughput reaches ~1 Mbps in master mode. CCP timers handle inter-frame timing and bus arbitration delays. The 33 I/O accommodate multiple simultaneous buses plus status LEDs. Industrial temperature grade suits factory-floor protocol conversion.
Recommended
Embedded Display & Keypad Interfaces
The PIC16C65A-04I/PQ drives character LCDs (HD44780-compatible) and 4x4 matrix keypads via its 33 I/O pins. PORTC and PORTD provide 16 pins sufficient for 8-bit LCD data bus plus 6 control lines (RS, RW, E, backlight, contrast), leaving PORTB and PORTE for keypad scanning with interrupt-on-change. 7 KB OTP holds character set mapping, menu navigation, and keypad debounce state machines. The USART enables remote terminal or HMI uplink. SPI drives graphical LED matrix displays. Industrial temperature range supports outdoor kiosks and machine-tool operator panels. Migration path: PIC16F877A for graphical LCD support with the same 44-pin MQFP footprint.
Recommended
Legacy Embedded System Upgrades
The PIC16C65A-04I/PQ is a common choice for maintaining and upgrading legacy 1990s-2000s embedded products where the original PIC16C65B or PIC16C65 was specified. Its drop-in compatibility with the broader PIC16C6X family (same instruction set, similar peripheral register maps) makes it a low-risk substitution for failed units or product refresh cycles. The industrial temperature grade matches legacy production equipment operating specs. Many OEMs use it as a long-term continuity part while evaluating migration to PIC16F877A (flash, in-circuit reprogrammable) for new revisions. The 44-MQFP footprint preserves PCB layout investment across PIC16C6X family variants. Long Microchip lifecycle commitment supports 10-20 year product support windows.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C65A-04I/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C65A-04I/P | PIC16C65A-04/PQ | PIC16F877A-I/PQ | PIC16C64A-04I/PQ | PIC16C64AT-04I/PQ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (10x10 mm) | 40-PDIP (through-hole) | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 4 MHz | 4 MHz |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 14 KB Flash | 4 KB OTP | 4 KB OTP |
| RAM | 192 bytes | 192 bytes | 192 bytes | 368 bytes | 128 bytes | 128 bytes |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 33 |
| Operating Voltage | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 2.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V |
| Temperature Range | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
| Memory Type | OTP EPROM | OTP EPROM | OTP EPROM | Flash (ICSP) | OTP EPROM | OTP EPROM |
| In-Circuit Programming | No (parallel programmer required) | No (parallel programmer required) | No (parallel programmer required) | Yes (ICSP via RB6/RB7) | No (parallel programmer required) | No (parallel programmer required) |
Key Differentiators
- Industrial temperature grade in surface-mount MQFP (vs PIC16C65A-04/PQ)
- 44-MQFP surface-mount package with 33 I/O (vs PIC16C65A-04I/P)
- Mature, long-life industrial product (vs PIC16F877A-I/PQ)
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible to each VDD pin (pins 20, 33, 43) with a short trace to the adjacent Vss pin. Add a 10 uF bulk tantalum or aluminum electrolytic capacitor at the board's power entry point. The PIC16C65A's ADC accuracy degrades with noisy VDD; for sensor applications, use a separate low-dropout regulator (e.g., Microchip MCP1700) to power the analog supply rail. The 5V supply must be regulated to within +/-5% - operation below 4.0 V is out-of-spec and may cause EPROM programming voltage issues during firmware load.
The 44-MQFP package (10x10 mm body, 0.8 mm lead pitch) requires reflow soldering with proper land pattern per IPC-7351. Keep traces under the package short and avoid routing signals beneath the die. MCLR pin (pin 9) should have a 10 kohm pull-up to VDD and a 100 nF capacitor to Vss for noise immunity; this prevents spurious resets from switching noise on long cables. OSC1/OSC2 traces (pins 7-8) should be short and symmetric - keep crystal within 10 mm of the MCU and guard with ground pour. For industrial environments, add TVS diodes on MCLR and supply rails for transient protection.
Common pitfalls when designing with PIC16C65A-04I/PQ: (1) OTP memory cannot be re-programmed - every firmware bug during development requires a new MCU; use PIC16F877A or windowed CERDIP for prototypes. (2) The ADC reference voltage is VDD - noisy supplies cause ADC noise; use an external reference for precision measurements. (3) PORTB pull-ups must be enabled via OPTION_REG; many engineers forget this for keypad scanning applications. (4) Interrupt-on-change on PORTB requires reading the port to clear the mismatch condition, otherwise the interrupt re-fires indefinitely. (5) The USART BRGH bit must be set correctly for the chosen baud rate at 4 MHz clock; standard 9600 baud is achievable but error margins are tight.
Compliance Information
RoHS/lead-free status not specified in the verified web data - marked as unknown. The MQFP package was historically leaded; verify with Microchip product page or distributor for current RoHS compliance. PIC16C65A is not AEC-Q100 qualified.
