PIC16C77-20/PQ - 8-bit 20MHz 14KB OTP MCU, 44-MQFP | Microchip
MPN: PIC16C77-20/PQ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.55 | $7.55 |
| 10 | $6.8 | $68.00 |
| 100 | $6.05 | $605.00 |
| 500 | $5.4 | $2,700.00 |
| 1,000 | $4.78 | $4,780.00 |
PIC16C77-20/PQ Overview
What is a microcontroller (MCU)? An MCU is a single-chip computer that integrates a CPU core, program memory (ROM/OTP/Flash), data RAM, and peripherals such as timers, communication ports, and analog-to-digital converters. The PIC16C7X family is classified within the PIC mid-range hierarchy, sitting between baseline PIC10/12/16 devices and enhanced mid-range PIC16F1xxx devices. It is widely used in industrial control, instrumentation, and embedded systems where deterministic 8-bit processing and OTP (one-time-programmable) memory are required for cost-sensitive or end-of-life-locked firmware.
Key features include three timer/counters (Timer0, Timer1, Timer2), two Capture/Compare/PWM (CCP) modules for motor or power control, two serial ports (USART/SCI and SSP/SPI/I2C), 8 channels of 8-bit A/D conversion, and a 14-bit instruction word optimized for compact code density. The 44-pin MQFP package provides ample I/O for parallel bus interfaces, keypad scans, and LCD drive applications.
The PIC16C77 is built on a fully-static CMOS process that supports DC to 20MHz operation across the commercial and industrial temperature ranges. Its RISC core, 8-level deep hardware stack, and Harvard bus architecture deliver deterministic interrupt response suitable for real-time control loops. The integrated 8-bit ADC with multiple input channels makes it well-suited for sensor multiplexing in process control and instrumentation.
Typical applications include industrial process controllers, sensor signal conditioning front-ends, motor control boards, instrumentation front panels, and embedded systems requiring OTP-based firmware. Microchip notes that newer designs should consider the flash-based PIC16F77 for in-system reprogrammability, while the PIC16C77-20/PQ remains in active legacy production for long-life-cycle programs.
When designing with this MCU, ensure a stable 20MHz clock source and verify that the brown-out reset and watchdog timer are configured to your application's reliability requirements. OTP memory cannot be re-programmed, so firmware validation on a flash-equivalent (PIC16F77) prior to OTP commitment is a strongly recommended workflow.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that complement - but do not replace - the manufacturer datasheet, helping engineers evaluate lifecycle and replacement options.
Drop-in alternatives for PIC16C77-20/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 PIC16C77-20/PQ (same form factor and footprint) — differing in Package, Serial Interfaces, Timers, Instruction Cycle Time, A/D Converter.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F77-I/PQ
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C77-20I/PQ
✅ Drop-In✓ In Stock
$7.96 / Unit
View Datasheet →PIC16C77-20E/PQ
✅ Drop-In✓ In Stock
$4.55 / Unit
View Datasheet →PIC16C77-04I/PQ
✅ Drop-In✓ In Stock
$7.16 / Unit
View Datasheet →PIC16C77-10I/PQ
✅ Drop-In✓ In Stock
$9.85 / Unit
View Datasheet →PIC16C77-20/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16CXX mid-range 8-bit RISC |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 14 KB (8K x 14 words) |
| RAM | 368 bytes |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Instruction Set Size | 35 single-word instructions |
| Data EEPROM | Not present (OTP family) |
| I/O Pins | 33 |
| A/D Converter | 8 channels, 8-bit resolution |
| Timers | 3 (Timer0, Timer1, Timer2) |
| CCP Modules | 2 (Capture/Compare/PWM) |
| Serial Communication | 1 x USART/SCI + 1 x SSP (SPI/I2C) |
| Package | 44-MQFP (10x10 mm) |
| Mounting Type | Surface Mount |
PIC16C77-20/PQ 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 — PORTA bit 2 / Analog input channel 2 |
| Pin 4 | RA3/AN3/VREF — PORTA bit 3 / Analog input channel 3 / ADC voltage reference |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 6 | RA5/AN4/SS — PORTA bit 5 / Analog input channel 4 / SPI slave select |
| Pin 7 | RE0/RD/AN5 — PORTE bit 0 / Read control for parallel slave port / Analog input channel 5 |
| Pin 8 | RE1/WR/AN6 — PORTE bit 1 / Write control for parallel slave port / Analog input channel 6 |
| Pin 9 | RE2/CS/AN7 — PORTE bit 2 / Chip select for parallel slave port / Analog input channel 7 |
| Pin 10 | VDD — Positive power supply |
| Pin 11 | VSS — Ground reference |
| Pin 12 | OSC1/CLKIN — Oscillator input / External clock input |
| Pin 13 | OSC2/CLKOUT — Oscillator output / Clock output |
| Pin 14 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 15 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 input/output |
| Pin 16 | RC2/CCP1 — PORTC bit 2 / CCP1 input/output |
| Pin 17 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 18 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 19 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 20 | RC6/TX/CK — PORTC bit 6 / USART async transmit / USART sync clock |
| Pin 21 | RC7/RX/DT — PORTC bit 7 / USART async receive / USART sync data |
| Pin 22 | RD0/PSP0 — PORTD bit 0 / Parallel slave port bit 0 |
| Pin 23 | RD1/PSP1 — PORTD bit 1 / Parallel slave port bit 1 |
| Pin 24 | RD2/PSP2 — PORTD bit 2 / Parallel slave port bit 2 |
| Pin 25 | RD3/PSP3 — PORTD bit 3 / Parallel slave port bit 3 |
| Pin 26 | RD4/PSP4 — PORTD bit 4 / Parallel slave port bit 4 |
| Pin 27 | RD5/PSP5 — PORTD bit 5 / Parallel slave port bit 5 |
| Pin 28 | RD6/PSP6 — PORTD bit 6 / Parallel slave port bit 6 |
| Pin 29 | RD7/PSP7 — PORTD bit 7 / Parallel slave port bit 7 |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive power supply |
| Pin 32 | RB0/INT — PORTB bit 0 / External interrupt input |
| Pin 33 | RB1 — PORTB bit 1 |
| Pin 34 | RB2 — PORTB bit 2 |
| Pin 35 | RB3/PGM — PORTB bit 3 / Low-voltage programming input |
| Pin 36 | RB4 — PORTB bit 4 |
| Pin 37 | RB5 — PORTB bit 5 |
| Pin 38 | RB6/PGC — PORTB bit 6 / In-circuit debugger clock |
| Pin 39 | RB7/PGD — PORTB bit 7 / In-circuit debugger data |
| Pin 40 | MCLR/VPP — Master clear reset / Programming voltage input |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C77-20/PQ is suitable for 6 applications: Industrial Process Controllers, Motor Control and PWM Drive, Sensor Signal Conditioning Front-Ends, Instrumentation and Front-Panel Display Controllers, Embedded Serial Communication Gateways, Legacy Industrial and Aerospace Control Systems.
Industrial Process Controllers
The PIC16C77-20/PQ's 33 I/O pins and integrated 8-channel 8-bit ADC suit multi-loop process control where multiple sensor inputs and actuator outputs must be scanned deterministically. Its 20MHz operation (200ns instruction cycle) executes PID loops within sub-millisecond update intervals, while the 14KB OTP memory stores ladder-logic-equivalent control firmware locked at production time. The two CCP modules drive PWM outputs for valve or heater actuation, and the USART links the controller to SCADA HMI panels over RS-485. Compared with flash MCUs, the OTP architecture is well-matched to industrial systems where firmware rarely changes after commissioning and long-term code retention is mandated.
Recommended
Motor Control and PWM Drive
The PIC16C77-20/PQ's two Capture/Compare/PWM (CCP) modules generate complementary PWM signals suitable for brushed DC motor speed control, small BLDC commutation, or stepper drive sequencing. The 20MHz instruction cycle produces PWM frequencies above 20kHz (above audible band) with fine duty resolution, while the 33 I/O lines interface to H-bridge gate drivers, encoder feedback, and overcurrent protection. The integrated 8-bit ADC samples motor current and back-EMF in real time, enabling closed-loop torque regulation. OTP-based code locking prevents firmware tampering in commercial motor products.
Recommended
Sensor Signal Conditioning Front-Ends
With 8 channels of 8-bit ADC and 33 I/O, the PIC16C77-20/PQ multiplexes multiple analog sensors (temperature, pressure, flow, level) and outputs linearized digital values over its USART. The 20MHz RISC core executes polynomial linearization and digital filtering routines in real time without external DSP hardware. The OTP memory stores calibrated compensation coefficients per sensor channel. The MQFP package's compact 10x10mm footprint allows the MCU to sit alongside analog front-end op-amps on a small mixed-signal PCB, ideal for multi-channel data acquisition modules.
Recommended
Instrumentation and Front-Panel Display Controllers
The PIC16C77-20/PQ drives character LCDs, 7-segment LED displays, and matrix keypads via its 33 I/O pins, while monitoring user input and sensor feedback simultaneously. The integrated USART links to host PCs or printers for data logging, and the CCP modules generate timing signals for measurement gating. The 368-byte RAM buffers measurement samples before serial transmission, and the 200ns instruction cycle ensures responsive keypad debounce and menu navigation. OTP memory locks calibration constants to prevent field tampering in certified test equipment.
Recommended
Embedded Serial Communication Gateways
With both USART (SCI) and SSP (SPI/I2C) ports, the PIC16C77-20/PQ bridges legacy serial peripherals to modern SPI/I2C sensor networks, acting as a protocol converter or gateway node. The 20MHz clock provides ample processing bandwidth to buffer and forward messages without throughput bottleneck. The 8-bit ADC adds analog telemetry to the gateway, while 33 I/O handle discrete digital inputs from field equipment. OTP firmware locking prevents unauthorized reconfiguration in deployed industrial gateways, satisfying cybersecurity baselines for operational technology.
Recommended
Legacy Industrial and Aerospace Control Systems
The PIC16C77-20/PQ remains in active production specifically for long-life-cycle programs including aerospace subsystems, military field equipment, and certified industrial machinery where firmware has been validated and locked for decades. Microchip's policy of supporting the PIC16C7X family as legacy active parts ensures continued supply for these programs. The OTP memory and extended temperature variants (PIC16C77-20I/PQ industrial, PIC16C77-20E/PQ extended) meet the environmental and reliability requirements of these applications, while the 44-MQFP package remains compatible with original PCB layouts from the 1990s design era.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C77-20/PQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F77-I/PQ | PIC16C77-20I/PQ | PIC16C77-20E/PQ | PIC16C77-04I/PQ |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (10x10 mm) | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same | 44-MQFP (10x10 mm) - same |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 4 MHz |
| Program Memory Type | OTP | Flash (reprogrammable) | OTP | OTP | OTP |
| Program Memory Size | 14 KB (8K x 14) | 14 KB | 14 KB | 14 KB | 14 KB |
| RAM | 368 bytes | 368 bytes | 368 bytes | 368 bytes | 368 bytes |
| Temperature Grade | Commercial (0C to +70C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Extended (-40C to +125C) | Industrial (-40C to +85C) |
| A/D Converter | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit |
| I/O Pins | 33 | 33 | 33 | 33 | 33 |
| Drop-in Compatibility | Reference part | Yes - identical peripherals, flash vs OTP | Yes - identical silicon, industrial temp | Yes - identical silicon, extended temp | Yes - same peripherals, 4MHz vs 20MHz |
Key Differentiators
- In-system reprogrammability on identical footprint (vs PIC16F77-I/PQ)
- Industrial temperature range option (vs PIC16C77-20I/PQ)
- Extended temperature grade for harsh environments (vs PIC16C77-20E/PQ)
- Lower clock grade available for power-sensitive designs (vs PIC16C77-04I/PQ)
Design Notes
The PIC16C77-20/PQ uses one-time-programmable (OTP) memory. Once a program is written, it cannot be erased or rewritten. This makes firmware validation on a flash-based equivalent (PIC16F77) absolutely essential before OTP commitment. Build and debug your firmware on a PIC16F77 development board first, then commit the validated .hex file to PIC16C77-20/PQ units in production programming. Any firmware bug discovered post-OTP requires discarding the silicon.
The 44-MQFP package uses a 0.8mm lead pitch with a 10x10mm body. Maintain at least 0.4mm clearance between adjacent leads on the land pattern and verify solder paste stencil aperture matches IPC-7525 recommendations for fine-pitch QFP packages (typically 0.15mm stencil thickness). Place a 0.1uF decoupling capacitor within 5mm of each VDD pin (pins 10 and 31) and a bulk 10uF tantalum or ceramic capacitor near the MCU supply entry point.
The PIC16C77-20/PQ requires a stable VDD within the datasheet-specified range (typically 4.0V to 6.0V for the PIC16C7X family). Brown-out reset (BOR) should be enabled in the configuration word to prevent code execution at low VDD where memory read errors can corrupt program flow. The MCLR pin (pin 40) should be pulled to VDD through a 10kohm resistor with a 100nF capacitor to ground for power-on reset stability; do not leave MCLR floating as it can cause spurious resets.
Place the 20MHz crystal or resonator within 10mm of the OSC1/OSC2 pins (pins 12 and 13) and keep the oscillator traces short and surrounded by a ground guard ring to minimize EMI coupling. If using an external clock source, route the clock signal over a continuous ground plane and avoid crossing any high-frequency switching traces. The analog inputs (RA0-RA5, RE0-RE2) should be physically separated from digital switching signals; place the AVSS/AVDD supply pair with their own decoupling and consider a ferrite bead between digital and analog supply domains.
The PIC16C77-20/PQ's parallel slave port (PORTD plus PORTE control lines) operates at the full 20MHz instruction rate and can generate fast edge rates. When interfacing PORTD to external memory or bus peripherals, add 33 ohm series damping resistors near the MCU pins to reduce transmission-line ringing. For long PCB traces (>50mm), consider a buffer/driver to isolate bus capacitance. The I2C/SPI pins (RC3/RC4/RC5) require pull-up resistors on SCL/SDA lines per I2C specification; 4.7kohm is typical for 100kHz Standard-mode and 2.2kohm for 400kHz Fast-mode operation.
Compliance Information
Compliance values not explicitly stated in the verified web data; RoHS, REACH, lead-free, and halogen-free status should be confirmed via Microchip's product environmental compliance page. Conflict minerals compliance typical for Microchip legacy PIC16C family.
