PIC16C65B-20E/P - 8-Bit OTP MCU 7KB 20MHz DIP-40 | Microchip
MPN: PIC16C65B-20E/P ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.2 | $8.20 |
| 10 | $7.45 | $74.50 |
| 100 | $6.6 | $660.00 |
| 500 | $5.85 | $2,925.00 |
| 1,000 | $5.2 | $5,200.00 |
PIC16C65B-20E/P Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, memory, and programmable I/O peripherals. The PIC16C65B belongs to Microchip's mid-range PIC16C architecture, which sits between the baseline PIC10/12/16 families and the enhanced PIC18 family. The 65B is a one-time-programmable (OTP) variant using EPROM technology, which historically enabled high-volume, low-cost embedded designs that did not require firmware field updates. It shares its instruction set and peripheral set with the PIC16C63A, 73B, and 74B siblings, making it part of a scalable, code-compatible product family.
Key features include 33 digital I/O pins, three 8-bit timer/counters (Timer0, Timer1, Timer2), two capture/compare/PWM modules, a USART for serial communication, an 8-bit parallel slave port, and a watchdog timer with its own on-chip RC oscillator. Power consumption is exceptionally low: typical operating current is 15 µA at 5 V/4 MHz and only 1 µA in standby at 3 V/32 kHz, supporting battery-powered applications. The device provides 15 interrupt sources and a fully static CMOS design that permits operation down to DC clock rates.
The PIC16C65B integrates a RISC architecture with 35 single-word instructions, 200 ns instruction execution time at 20 MHz, a 14-bit instruction word, and an 8-bit data path. It uses a Harvard architecture with separate program and data buses, two 8-bit file select registers, and a hardware stack of eight levels for subroutine/interrupt nesting. The internal oscillator mode is not provided on this OTP device; it requires an external crystal, resonator, or RC clock source on OSC1/OSC2.
Typical applications include industrial control panels, automotive body and chassis ECUs, instrumentation, motor control front-ends, and embedded serial communication gateways. Its automotive grade and OTP cost structure also make it a fit for high-volume appliance control and HVAC control modules. Designers choose this part when code is finalized and low per-unit cost is more important than field re-programmability.
A key design consideration is that OTP cannot be electrically re-programmed; any code change after programming requires a new device, so verification must be done on a windowed or flash-equivalent part (such as PIC16F877) during prototyping. Also, since this part is in the legacy OTP product line, lifecycle availability is constrained compared to flash PIC16F replacements - validate supply before committing to a new design.
Drop-in alternatives for PIC16C65B-20E/P — 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-20E/P (same form factor and footprint) — differing in Mounting Type, Timers, Core Architecture, Package, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C65B-04E/P
✅ Drop-In✓ In Stock
$5.45 / Unit
View Datasheet →PIC16C65B-20I/P
✅ Drop-In✓ In Stock
$5.42 / Unit
View Datasheet →PIC16F877-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C65B-04I/P
✅ Drop-In✓ In Stock
$3.75 / Unit
View Datasheet →PIC18F452-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C65A-20E/PQ
✅ Drop-In✓ In Stock
$4.85 / Unit
View Datasheet →PIC16C65B-20E/P Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Part Family | PIC16C mid-range 8-bit |
| Device Type | 8-Bit Microcontroller (MCU) |
| Program Memory Type | OTP EPROM (non-reprogrammable) |
| Program Memory Size | 7 KB (4K x 14 words) |
| RAM Size | 192 bytes |
| Data EEPROM | Not present (0 bytes) |
| Maximum CPU Frequency | 20 MHz |
| Instruction Execution Time | 200 ns at 20 MHz |
| Instruction Set Size | 35 single-word instructions |
| Operating Voltage Range | 2.5 V to 6.0 V |
| Temperature Grade (E suffix) | Extended / Automotive -40C to +125C |
| I/O Pins | 33 digital I/O |
| Timers | 3 (Timer0 8-bit, Timer1 16-bit, Timer2 8-bit) |
| CCP Modules | 2 (Capture / Compare / PWM) |
| Communication | USART (SCI), 8-bit Parallel Slave Port |
| Watchdog Timer | Yes (with dedicated on-chip RC oscillator) |
| Interrupts | 15 sources |
| Package Type | PDIP-40 (40-pin Plastic DIP, 0.600 inch / 15.24 mm row spacing) |
| Mounting Type | Through-Hole (THT) |
| Pin Count | 40 |
| RoHS Status | Non-compliant (legacy OTP product) |
| Operating Power Consumption | 15 uA typical at 5 V / 4 MHz |
| Standby Current | 1 uA typical at 3 V / 32 kHz |
PIC16C65B-20E/P Pin Configuration
| Pin 1 | MCLR — Master Clear (Reset) input, active low |
| Pin 2 | RA0 — PORTA bit 0 (digital I/O or analog input) |
| Pin 3 | RA1 — PORTA bit 1 |
| Pin 4 | RA2 — PORTA bit 2 |
| Pin 5 | RA3 — PORTA bit 3 |
| Pin 6 | RA4 — PORTA bit 4 (also Timer0 clock input) |
| Pin 7 | RA5 — PORTA bit 5 |
| Pin 8 | RE0 — PORTE bit 0 (also PSP read control) |
| Pin 9 | RE1 — PORTE bit 1 (also PSP write control) |
| Pin 10 | RE2 — PORTE bit 2 (also PSP CS control) |
| Pin 11 | VDD — Positive supply voltage (logic) |
| Pin 12 | VSS — Ground reference (logic) |
| Pin 13 | OSC1 — Crystal/Resonator input or external clock |
| Pin 14 | OSC2 — Crystal/Resonator output |
| Pin 15 | RC0 — PORTC bit 0 (also Timer1 oscillator output) |
| Pin 16 | RC1 — PORTC bit 1 (also CCP2 output) |
| Pin 17 | RC2 — PORTC bit 2 (also CCP1 output) |
| Pin 18 | RC3 — PORTC bit 3 (also USART TX) |
| Pin 19 | RC4 — PORTC bit 4 (also USART RX) |
| Pin 20 | RC5 — PORTC bit 5 (also SDI) |
| Pin 21 | RC6 — PORTC bit 6 (also TX/CK) |
| Pin 22 | RC7 — PORTC bit 7 (also RX/DT) |
| Pin 23 | RB0 — PORTB bit 0 (external interrupt input) |
| Pin 24 | RB1 — PORTB bit 1 |
| Pin 25 | RB2 — PORTB bit 2 |
| Pin 26 | RB3 — PORTB bit 3 |
| Pin 27 | RB4 — PORTB bit 4 |
| Pin 28 | RB5 — PORTB bit 5 |
| Pin 29 | RB6 — PORTB bit 6 (also ICSP clock) |
| Pin 30 | RB7 — PORTB bit 7 (also ICSP data) |
| Pin 31 | VSS — Ground reference |
| Pin 32 | RD0 — PORTD bit 0 (Parallel Slave Port data) |
| 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 | VDD — Positive supply voltage (logic) |
Typical Applications
PIC16C65B-20E/P is suitable for 6 applications: Automotive Body Control ECU, Industrial Instrumentation Front-End, HVAC Control Module, Appliance Control Board, Serial Communication Gateway, Motor Control Front-End.
Automotive Body Control ECU
The PIC16C65B-20E/P fits automotive body ECUs because its E temperature grade covers -40C to +125C, matching under-hood thermal stress. Its 7 KB OTP EPROM stores fixed lighting, wiper, and door-lock control firmware, while 33 digital I/O pins directly drive relay and MOSFET drivers. The 20 MHz CPU executes 200 ns instructions, sufficient for 10 ms PWM channels controlling interior lighting dimming. Three timers (Timer0/1/2) generate hardware PWM without software overhead, and the USART interfaces with LIN or K-Line transceivers for in-vehicle networking. Compared to flash parts, OTP reduces per-unit cost in high-volume ECUs where firmware is finalized. Design tip: add a 100 nF decoupling cap on each VDD/AVDD pair, place MCLR pull-up resistor near the IC, and reserve a 4-pin ICSP header for production programming since OTP cannot be field-updated.
Recommended
Industrial Instrumentation Front-End
The PIC16C65B-20E/P suits industrial instrumentation because its 33 digital I/O pins multiplex with on-chip comparators and ADC reference voltages to handle multi-channel sensor acquisition. The USART streams measurement data to host PCs or HMIs at 115200 bps, while the 8-bit parallel slave port connects directly to LCD controllers or parallel ADCs. With 192 bytes of RAM and 7 KB OTP, the device runs calibration tables, linearization routines, and Modbus RTU protocol stacks. The -40C to +125C temperature range supports factory-floor cabinet environments. Why this part fits: deterministic 200 ns instruction execution at 20 MHz guarantees jitter-free sampling windows without RTOS overhead. Design tip: route OSC1/OSC2 over a ground guard trace and keep the parallel port within 50 mm of the LCD connector to avoid bus reflections.
Recommended
HVAC Control Module
The PIC16C65B-20E/P integrates HVAC control logic including fan-speed PWM, temperature-sensor reading, and compressor relay sequencing in a single 40-pin PDIP footprint. Its two CCP modules generate the dual PWM channels needed for variable-speed blower motors and compressor soft-start, while the third timer (Timer0) handles the keypad scan interrupt. The 7 KB OTP EPROM accommodates fixed blower-curve lookup tables and fault-handling routines. The USART links to wall-thermostat networks, and 33 digital I/O drive relay coils, triac gates, and seven-segment displays. Why this part fits: the automotive-grade -40C to +125C temperature range covers attic and rooftop HVAC installations. Design tip: use optical isolation between the PIC's I/O and the 24 VAC triac driver stage, and add a TVS diode on MCLR for surge protection.
Recommended
Appliance Control Board
The PIC16C65B-20E/P is well suited to high-volume consumer appliance controllers including washing machines, dishwashers, and microwave ovens where the 7 KB OTP EPROM stores locked firmware and the 40-pin PDIP package supports low-cost wave-solder assembly. Three timers handle motor PWM, buzzer tones, and keypad debounce simultaneously. The CCP modules drive triac-fired heater elements and inverter interfaces, and the USART serves the diagnostic port for factory test. Why this part fits: 192 bytes RAM is sufficient for cycle counters, error logs, and sensor smoothing; 33 I/O pins handle LED arrays, button matrices, and solenoid drivers without external mux. The automotive temperature grade protects against hot-oven environments. Design tip: keep high-current traces separated from the analog AVCC/AVSS pair, and add a 10 uF bulk cap on VDD with a 100 nF bypass within 5 mm of the IC.
Recommended
Serial Communication Gateway
The PIC16C65B-20E/P acts as a serial protocol gateway bridging RS-232, RS-485, and proprietary sensor buses in industrial and building-automation networks. The USART handles the primary RS-232/RS-485 link at up to 115200 bps, while the 8-bit parallel slave port interfaces with an external wireless modem or Ethernet controller. With 7 KB OTP, the part runs full Modbus RTU or BACnet MS/TP protocol stacks. Why this part fits: 20 MHz CPU clock provides deterministic protocol turnaround time, and the automotive temperature grade supports outdoor cabinet installations. Design tip: add a TVS diode array on the RS-485 lines for surge protection, and isolate the PIC GND from the RS-485 transceiver GND with a 100 ohm resistor plus bypass capacitor.
Recommended
Motor Control Front-End
The PIC16C65B-20E/P serves as the control front-end in small BLDC or stepper motor drives for HVAC dampers, valve actuators, and conveyor systems. Two CCP modules deliver complementary PWM outputs with programmable dead-band control, while the 8-bit parallel slave port interfaces with an external gate driver or position-feedback encoder. The 20 MHz instruction rate sustains 8 kHz PWM switching with 1 us resolution. Why this part fits: the OTP EPROM stores tuned PI velocity-loop coefficients without risk of accidental field rewrites, and the -40C to +125C temperature grade handles motor compartment heat. Design tip: route PWM outputs on short traces with ground guard, and place a 10 kohm pull-up on MCLR to prevent spurious resets during motor inrush events.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C65B-20E/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C65B-04E/P | PIC16C65B-20I/P | PIC16F877-I/P | PIC16C65B-04I/P | PIC18F452-I/P | PIC16C65A-20E/P |
|---|---|---|---|---|---|---|---|
| Package | PDIP-40 | PDIP-40 - same | PDIP-40 - same | PDIP-40 - same | PDIP-40 - same | PDIP-40 - same | PDIP-40 - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 7 KB OTP EPROM | 7 KB OTP EPROM | 7 KB OTP EPROM | 14 KB flash | 7 KB OTP EPROM | 32 KB flash | 4 KB OTP EPROM |
| Maximum CPU Frequency | 20 MHz | 4 MHz | 20 MHz | 20 MHz | 4 MHz | 40 MHz | 20 MHz |
| RAM Size | 192 bytes | 192 bytes | 192 bytes | 368 bytes | 192 bytes | 1536 bytes | 192 bytes |
| Temperature Grade | Extended -40C to +125C | Extended -40C to +125C | Industrial -40C to +85C | Industrial -40C to +85C | Industrial -40C to +85C | Industrial -40C to +85C | Extended -40C to +125C |
| Operating Voltage | 2.5 V to 6.0 V | 2.5 V to 6.0 V | 2.5 V to 6.0 V | 2.0 V to 5.5 V | 2.5 V to 6.0 V | 2.0 V to 5.5 V | 2.5 V to 6.0 V |
| Data EEPROM | Not present (0 bytes) | Not present | Not present | 256 bytes | Not present | 256 bytes | Not present |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Active | Obsolete | Active | Obsolete |
Key Differentiators
- Same PDIP-40 footprint and pinout as PIC16F877 family (vs PIC16F877-I/P)
- Extended automotive temperature grade (-40C to +125C) (vs PIC16C65B-20I/P)
- 20 MHz CPU with 200 ns instruction execution (vs PIC16C65B-04E/P)
- OTP EPROM reduces per-unit cost in high volume (vs PIC16F877-I/P)
Design Notes
OTP EPROM cannot be erased electrically. Any code change after programming requires a new device, so the entire firmware must be locked and verified on a windowed or flash-equivalent (PIC16F877) before production programming. Allow at least one full regression cycle on the flash part, then commit the final HEX to the PIC16C65B OTP units. Mismatched configuration bits between PIC16C65B and PIC16F877 are the most common porting failure - explicitly set oscillator, watchdog, brown-out, and code-protection bits identically.
Place a 100 nF ceramic decoupling capacitor within 5 mm of each VDD pin (pins 11 and 40) and a 10 uF bulk electrolytic or tantalum capacitor on the VDD rail. Add a separate 100 nF on AVCC/AVSS if your design references analog voltages. Keep the analog and digital ground returns separated and tied only at the PIC's VSS pin (pin 31) to avoid ground-loop noise on the ADC. Estimated active current at 5 V / 20 MHz is approximately 20 mA per the PIC16C65B family datasheet; ensure the regulator has at least 50 mA headroom.
The 40-pin PDIP package has 0.1 inch (2.54 mm) pin pitch and 0.6 inch (15.24 mm) row spacing. Route all 33 I/O traces on a single top layer with the MCU centered on the board to minimize trace lengths. Reserve a 4-pin ICSP header (MCLR, VDD, VSS, RB6, RB7) on every board revision - even in production, since OTP devices still need factory programming through ICSP. For automotive designs, add a TVS diode on MCLR to absorb load-dump transients.
At 5 V and 20 MHz, the PIC16C65B-20E/P draws approximately 20 mA active, dissipating 100 mW of power. Junction-to-ambient thermal resistance for the PDIP-40 package is approximately 50 C/W, yielding a 5 C temperature rise above ambient - well within safe limits. Even at the 125 C automotive ceiling, internal power dissipation does not exceed thermal derating. No external heatsink is required for the PDIP package under any normal operating condition.
The parallel slave port (PORTD plus PORTE control) operates at the CPU clock rate; keep the parallel port traces within 50 mm of the connected LCD/ASIC and add 33 ohm series resistors on each data line to dampen reflections. The USART pins (RC6/RC7) can run at 115200 bps cleanly at 20 MHz but require a 100 ohm series resistor and ground guard if the cable leaves the PCB. Crystal traces on OSC1/OSC2 must be short, symmetrical, and surrounded by a grounded guard ring to avoid spurious injection from PWM outputs.
Compliance Information
Legacy OTP product line; not lead-free per PIC16C65B family datasheet. RoHS status to be confirmed at order entry. AEC-Q100 qualification status not formally documented for the PIC16C65B-20E/P variant.
