PIC16C65B-04I/PQ - 8-Bit 4MHz MCU 7KB OTP 33 I/O | Microchip
MPN: PIC16C65B-04I/PQ ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.45 | $5,450.00 |
PIC16C65B-04I/PQ Overview
A microcontroller (MCU) is a single-chip computer containing a processor core, program and data memory, and peripheral interfaces. Within the broader semiconductor taxonomy, an MCU sits below microprocessor (MPU) and above DSP and ASIC in system-integration depth. The PIC16CXX mid-range family is one of Microchip's foundational 8-bit lines, characterized by a 14-bit instruction word and Harvard architecture - meaning separate program and data buses - delivering deterministic interrupt latency and compact code density relative to von-Neumann 8-bit alternatives.
Key features include 33 digital I/O pins arranged across multiple ports (PORTB through PORTE), two 8-bit timer/counters plus one 16-bit timer/counter, a synchronous serial port (SSP) supporting SPI and I2C master/slave modes, and a brown-out reset (BOR) circuit. The industrial temperature grade ('I' suffix) guarantees operation from -40 C to +85 C, while the 04 speed grade denotes a 4 MHz maximum oscillator input. The OTP memory architecture supports prototype runs and low-to-medium volume production where flash reprogrammability is not required.
Architecturally, the PIC16C65B uses a Harvard bus with a 14-bit program word and 8-bit data path, achieving single-cycle instruction execution except for branches. The 4 MHz oscillator combined with a 4:1 internal divider yields a 1 MHz instruction clock, with 1 MIPS sustained throughput. Brown-out reset, watchdog timer, and power-on reset are integrated, reducing external component count in cost-sensitive designs.
Typical applications include industrial automation controllers, embedded instrumentation with the on-chip ADC, motor control via the CCP PWM outputs, point-of-sale terminals, and legacy embedded systems where PIC16C-series firmware is already deployed. The OTP memory makes the device well-suited to production runs once firmware is finalized.
When designing with this part, verify that the 4 MHz oscillator limit is compatible with required throughput, and ensure the OTP memory strategy aligns with production volume - if firmware updates are anticipated, choose the PIC16F-series flash equivalent. The MQFP package requires a minimum 1 oz copper pour and thermal vias for reliable operation above 25 C ambient.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC16C65B-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 PIC16C65B-04I/PQ (same form factor and footprint) — differing in Timers, Package, Program Memory Type, Mounting Type, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C65B-04E/PQ
✅ Drop-In✓ In Stock
$11.1 / Unit
View Datasheet →PIC16C65B-04/PQ
✅ Drop-In✓ In Stock
$10.25 / Unit
View Datasheet →PIC16C65A-04I/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C65AT-04I/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C65A-20I/PQ
✅ Drop-In✓ In Stock
$8.62 / Unit
View Datasheet →PIC16C65B-04I/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC mid-range (Harvard) |
| Instruction Set Width | 14-bit |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 7 KB (4K x 14 words) |
| RAM Size | 192 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Throughput | 1 MIPS |
| I/O Pins | 33 |
| ADC Channels | 5 x 8-bit (on 'B' silicon) |
| Timers | Two 8-bit + one 16-bit |
| CCP Modules | 2 |
| Communication Peripherals | USART, SSP (SPI / I2C), Parallel Slave Port |
| Supply Voltage | 4.0 V to 6.0 V |
| Operating Temperature | -40 C to +85 C (Industrial, 'I' suffix) |
| Package | 44-pin MQFP (10 x 10 mm) |
| Mounting Type | Surface Mount |
| Speed Grade | 04 (4 MHz max) |
PIC16C65B-04I/PQ Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage |
| 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 / ADC voltage reference |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer 0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / Analog input 4 / SPI slave select |
| Pin 8 | VSS — Ground |
| Pin 9 | OSC1/CLKIN — Oscillator crystal input / external clock |
| Pin 10 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer 1 oscillator output / Timer 1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer 1 oscillator input / CCP2 output |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 output |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 19 | VSS — Ground |
| Pin 20 | VDD — Positive supply voltage |
| Pin 21 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 22 | RB1 — PORTB bit 1 |
| Pin 23 | RB2 — PORTB bit 2 |
| Pin 24 | RB3 — PORTB bit 3 |
| Pin 25 | RB4 — PORTB bit 4 |
| Pin 26 | RB5 — PORTB bit 5 |
| Pin 27 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 28 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 29 | VSS — Ground |
| Pin 30 | VDD — Positive supply voltage |
| Pin 31 | VSS — Ground |
| Pin 32 | RD0 — PORTD bit 0 (parallel slave port data) |
| Pin 33 | RD1 — PORTD bit 1 (parallel slave port data) |
| Pin 34 | RD2 — PORTD bit 2 (parallel slave port data) |
| Pin 35 | RD3 — PORTD bit 3 (parallel slave port data) |
| Pin 36 | RD4 — PORTD bit 4 (parallel slave port data) |
| Pin 37 | RD5 — PORTD bit 5 (parallel slave port data) |
| Pin 38 | RD6 — PORTD bit 6 (parallel slave port data) |
| Pin 39 | RD7 — PORTD bit 7 (parallel slave port data) |
| Pin 40 | RE0/RD/AN5 — PORTE bit 0 / parallel slave port read / Analog input 5 |
| Pin 41 | RE1/WR/AN6 — PORTE bit 1 / parallel slave port write / Analog input 6 |
| Pin 42 | RE2/CS/AN7 — PORTE bit 2 / parallel slave port chip select / Analog input 7 |
| Pin 43 | VDD — Positive supply voltage |
| Pin 44 | VSS — Ground |
Typical Applications
PIC16C65B-04I/PQ is suitable for 6 applications: Industrial Automation Controller, Embedded Instrumentation with ADC, Motor Control with CCP PWM, Point-of-Sale Terminal, Legacy System Maintenance, Educational and Training Boards.
Industrial Automation Controller
The PIC16C65B-04I/PQ fits industrial PLC and machine controller boards where its 33 digital I/O pins, two CCP/PWM modules, and 5-channel 8-bit ADC directly drive sensor inputs, relay outputs, and PWM-controlled valves or motors. The 4 MHz throughput is sufficient for sequencing relay logic and reading analog process variables at sub-kHz rates. Industrial -40 C to +85 C temperature rating supports factory-floor enclosures without additional thermal conditioning. Drop-in compatibility with PIC16C65B-04/PQ enables stocking a single PCB for both commercial and industrial variants.
Recommended
Embedded Instrumentation with ADC
The PIC16C65B-04I/PQ's 5-channel 8-bit on-chip ADC eliminates an external converter in digital panel meters, weigh scales, and process indicators. Combined with the I2C/SPI SSP for sensor interfacing and USART for data logging output, the device functions as a complete single-chip measurement subsystem. The 192-byte RAM supports local data buffering before UART transmission. Industrial temperature rating suits outdoor and uncontrolled-environment deployments.
Recommended
Motor Control with CCP PWM
The two on-chip Capture/Compare/PWM modules of the PIC16C65B-04I/PQ drive brushed DC motor speed control and small stepper sequencing in appliance, fan, and pump controllers. The 33 I/O pins handle direction relays, enable lines, and Hall-effect sensor inputs. At 4 MHz the PWM frequency is suitable for sub-10 kHz motor drive, well within audible band limits for low-noise applications. The industrial temperature grade supports HVAC and white-goods deployments.
Recommended
Point-of-Sale Terminal
POS terminals and electronic cash registers use the PIC16C65B-04I/PQ for keyboard scanning, display driving, and serial communication to receipt printers via the USART. The 7 KB OTP program memory fits legacy firmware, and the 33 I/O pins accommodate 4x4 key matrices plus LCD interface lines. The 4 MHz throughput is adequate for transaction processing rates typical of retail terminals. Industrial temperature grade handles variable store environments.
Recommended
Legacy System Maintenance
The PIC16C65B-04I/PQ is maintained in production lines supporting installed equipment where firmware compatibility is mandatory. Customers with field-deployed PIC16C65B firmware continue sourcing this part for repair and refurbishment. The OTP memory prevents accidental firmware corruption during board swap. Industrial temperature rating matches the original deployment environment. Distributors continue stocking the part despite Microchip's obsolete classification for this aftermarket support role.
Recommended
Educational and Training Boards
Universities and embedded-systems training programs use the PIC16C65B-04I/PQ in microcontroller teaching laboratories because the mid-range 14-bit instruction set illustrates fundamental MCU concepts without the complexity of modern peripherals. The 44-pin MQFP package is widely accepted by academic soldering workstations, and the OTP architecture forces students to verify code before programming. The 4 MHz speed grade keeps timing analysis tractable for introductory coursework.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C65B-04I/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C65B-04E/PQ | PIC16C65B-04/PQ | PIC16C65A-04I/PQ | PIC16C65AT-04I/PQ | PIC16C65A-20I/PQ |
|---|---|---|---|---|---|---|
| Package | 44-pin MQFP (10x10 mm) | 44-pin MQFP (10x10 mm) - same | 44-pin MQFP (10x10 mm) - same | 44-pin MQFP (10x10 mm) - same | 44-pin MQFP (10x10 mm) - same | 44-pin MQFP (10x10 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB OTP |
| Operating Temperature | -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) |
| ADC Channels | 5 x 8-bit | 5 x 8-bit | 5 x 8-bit | None | None | None |
| Parallel Slave Port | Yes | Yes | Yes | No | No | No |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Integrated 5-channel 8-bit ADC on B silicon (vs PIC16C65A-04I/PQ)
- Parallel Slave Port for external bus interface (vs PIC16C65A-04I/PQ)
- Industrial temperature range vs commercial-only alternative (vs PIC16C65B-04/PQ)
Design Notes
Estimated: At 4 MHz clock with all peripherals active and 33 I/O pins loaded at typical CMOS input levels, the PIC16C65B-04I/PQ draws approximately 10-15 mA from a 5 V supply, dissipating roughly 50-75 mW. Place a 100 nF decoupling capacitor within 5 mm of each VDD pin and a 10 uF bulk capacitor at the board supply entry. The four VDD pins (20, 30, 31, 43) and four VSS pins (8, 19, 29, 31) must all be connected for proper operation.
The 44-pin MQFP package has 0.8 mm pitch leads; the PCB land pattern must follow IPC-7351 MQFP standards with 0.4 mm wide pads and 1.5 mm pad length. Route signals on inner layers only; keep the area beneath the package free of traces to allow post-solder inspection. Add a thermal pad pattern to the exposed die attach pad even though the MQFP-44 is not a true no-lead package, since the die-attach paddle improves heat spreading.
The PIC16C65B silicon requires a precise programming sequence for OTP memory; using a generic device programmer without the PIC16C65B device file will fail verification. Brown-out reset must be enabled in the configuration word for industrial deployments, or the device may execute corrupted code at supply-edge transitions. The MCLR pin cannot be left floating - tie through a 10 kohm pull-up to VDD to prevent spurious resets.
Compliance Information
Legacy OTP MQFP package is not lead-free; not AEC-Q100 qualified (consumer/industrial grade only). REACH status compliant per Microchip product declaration. For RoHS-compliant equivalent, choose PIC16F877A-20I/PQ.
