PIC16F677-I/SS - 8-bit 20MHz 3.5KB Flash MCU | Microchip | 20-SSOP
MPN: PIC16F677-I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.12 | $2.12 |
| 10 | $1.89 | $18.90 |
| 100 | $1.62 | $162.00 |
| 500 | $1.41 | $705.00 |
| 1,000 | $1.27 | $1,270.00 |
PIC16F677-I/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash/ROM), volatile working memory (RAM), non-volatile data storage (EEPROM), and a rich set of peripherals (ADC, timers, comparators, communication interfaces) into one IC. Within the broader system hierarchy, MCUs sit between simple digital logic and full microprocessors, enabling embedded control in everything from appliance keypads to industrial sensor nodes. The PIC16F677 belongs to the PIC16F "low pin-count" (20-pin) sub-family of the mid-range PIC microcontrollers.
Key features include 18 general-purpose digital I/O pins with individually programmable weak pull-ups, two 8-bit timers plus one 16-bit timer, one enhanced capture/compare/PWM (ECCP) module, two analog comparators, a 10-bit successive-approximation ADC with 12 channels, a USART for asynchronous serial communications, and nanoWatt Technology for ultra-low-power sleep modes consuming as little as 50 nA typical. The device supports in-circuit serial programming (ICSP) via two pins, allowing field firmware updates without removing the chip from the board.
The PIC16F677's nanoWatt power management and 2.0–5.5 V supply tolerance make it well suited to battery-powered applications such as remote sensors, low-end consumer products, and portable instruments where mains power is unavailable. Its on-chip 10-bit ADC with 12 analog inputs and dual comparators allow direct interface to analog sensors (temperature, light, voltage) without external signal conditioning, while the USART and SSP modules enable communication with companion ICs or host microprocessors.
Typical applications include home-automation sensor nodes, smoke and CO detector signal conditioning, HVAC thermostat control loops, low-end motor control via PWM, battery chargers with CC/CV profiles, industrial counter/totalizer panels, and remote control transmitter/receiver pairs. For each of these, the wide supply range tolerates USB, 4-series-NiMH, or single-cell Li-ion power rails.
When designing with this part, observe the Microchip header-file conventions and place a 0.1 µF decoupling capacitor within 5 mm of VDD with a short ground return; the /MCLR reset pin should be pulled up through a 10 kΩ resistor unless a manual-reset circuit is used. Confirm oscillator configuration bits before programming to avoid bootloader or timing errors.
This page synthesizes distributor pricing, drop-in same-family alternatives, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16F677-I/SS — 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 PIC16F677-I/SS (same form factor and footprint) — differing in Package, Timers, Core Architecture, ADC, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F677T-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F677-E/SS
✅ Drop-In✓ In Stock
$1.41 / Unit
View Datasheet →PIC16F690-I/SS
✅ Drop-In✓ In Stock
$1.41 / Unit
View Datasheet →PIC16F676-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F677-I/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 mid-range x14 (RISC) |
| Program Memory | 3.5 KB (2K x 14) Flash |
| Data EEPROM | 128 bytes |
| Data RAM | 128 bytes |
| Maximum CPU Frequency | 20 MHz (200 ns instruction cycle) |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| I/O Pins | 18 |
| ADC | 10-bit, up to 12 channels |
| Comparators | 2 analog comparators |
| Timers | 2 x 8-bit + 1 x 16-bit |
| PWM Modules | 1 x ECCP (Enhanced Capture/Compare/PWM) |
| Serial Interfaces | 1 x USART, 1 x SSP (SPI/I2C) |
| Internal Oscillator | 8 MHz (calibrated ±1% typical) |
| Package | 20-pin SSOP (5.30 mm body) |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| Mounting Type | Surface Mount |
| MSL Level | MSL1 |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC16F677-I/SS Pin Configuration
| Pin 1 | /MCLR/VPP — Master Clear (reset) input / programming voltage |
| Pin 2 | RA0/AN0/C1IN+/ICSPDAT — Digital I/O / analog input 0 / comparator input / ICSP data |
| Pin 3 | RA1/AN1/C1IN-/ICSPCLK — Digital I/O / analog input 1 / comparator input / ICSP clock |
| Pin 4 | RA2/AN2/C1OUT — Digital I/O / analog input 2 / comparator 1 output |
| Pin 5 | RA3/AN3/C2IN+ — Digital I/O / analog input 3 / comparator 2 input + |
| Pin 6 | RA4/AN4/C2OUT/T0CKI — Digital I/O / analog input 4 / comparator 2 output / Timer0 clock |
| Pin 7 | RA5/AN5/SS/HLVDIN — Digital I/O / analog input 5 / SSP slave select / high/low voltage detect |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RA7/OSC1/CLKI — Digital I/O / oscillator crystal input / external clock input |
| Pin 10 | RA6/OSC2/CLKO — Digital I/O / oscillator crystal output / clock output |
| Pin 11 | RC0/AN8 — Digital I/O / analog input 8 |
| Pin 12 | RC1/AN9 — Digital I/O / analog input 9 |
| Pin 13 | RC2/AN10 — Digital I/O / analog input 10 |
| Pin 14 | RC3/AN11 — Digital I/O / analog input 11 |
| Pin 15 | RC4/C2IN-/SDI/SDA — Digital I/O / comparator 2 input - / SPI data in / I2C data |
| Pin 16 | RC5/SDO — Digital I/O / SPI data out |
| Pin 17 | RC6/TX/CK — Digital I/O / USART transmit / USART clock |
| Pin 18 | RC7/RX/DT — Digital I/O / USART receive / USART data |
| Pin 19 | VSS — Ground reference |
| Pin 20 | VDD — Positive supply voltage (2.0 V to 5.5 V) |
Typical Applications
PIC16F677-I/SS is suitable for 6 applications: Battery-Powered Sensor Nodes, Smoke and CO Detector Signal Conditioning, HVAC Thermostat Control Loops, Low-End DC Motor Speed Control, Industrial Counter / Totalizer Panels, Battery Charger CC/CV Profiles.
Battery-Powered Sensor Nodes
The PIC16F677-I/SS is well matched to battery-powered wireless sensor nodes thanks to its 2.0–5.5 V supply range and nanoWatt Technology, which drops sleep current to sub-100 nA and lets a CR2032 cell run the node for years. The 10-bit ADC with up to 12 channels reads thermistor, photocell, or PIR sensors directly without external signal conditioning. Designers typically wake on a timer interrupt, sample the ADC, transmit via USART to a companion radio (e.g. an MRF89XA), and return to sleep. Compared to a Cortex-M0+ solution, the PIC16F677 reduces idle current ~5× while keeping firmware well below 3.5 KB for most telemetry frames.
Recommended
Smoke and CO Detector Signal Conditioning
The PIC16F677-I/SS excels in residential smoke and CO detector designs where its two on-chip analog comparators and 12-channel 10-bit ADC process the ion-chamber photocurrent, thermistor compensation, and piezo-driver feedback in a single chip. The wide 2.0–5.5 V VDD tolerates the 9 V battery + 3.3 V regulator stack commonly used in smoke alarms. The ECCP module drives the 3 kHz piezo sounder at controlled duty cycles while the USART lets the detector interface to interconnected alarm panels. At qty detection at 1,000 pieces the BOM cost stays under $1.30 per detector, fitting the consumer-safety price target.
Recommended
HVAC Thermostat Control Loops
In HVAC thermostat designs the PIC16F677-I/SS reads thermistor temperature via the 10-bit ADC, drives a triac-based HVAC compressor via ECCP PWM, and provides user-interface control through its 18 GPIO pins. Its 2.0–5.5 V operating range accepts 24 VAC-derived 5 V rails after rectification, simplifying the thermostat power supply. The PIC16F677's 35 single-word instruction set is straightforward enough to implement PID thermostat loops in under 2 KB of firmware, and the 128-byte EEPROM stores user setpoints across power cycles. Compared with a discrete logic solution, it consolidates sensing, control, and UI in one chip.
Recommended
Low-End DC Motor Speed Control
The PIC16F677-I/SS drives low-power brushless DC or brushed DC motors using its ECCP module for variable-frequency PWM, while the 10-bit ADC reads back EMF sensing or current-shunt voltage for closed-loop speed control. Its 20 MHz instruction rate (200 ns cycle) supports 8 kHz PWM with comfortable firmware overhead. The 2.0–5.5 V VDD range lets the PIC share the motor-driver supply rail without level shifting, reducing BOM cost in fans, pumps, and small appliances. At qty 1,000 the unit price of ~$1.27 keeps total motor-control BOM under $3 for cost-sensitive appliances.
Recommended
Industrial Counter / Totalizer Panels
Industrial counters, totalizers, and event-logger panels rely on the PIC16F677-I/SS for its 16-bit timer/counter, 128-byte EEPROM for non-volatile event logs, and 18 GPIO pins for LCD/keypad interfaces. The wide 2.0–5.5 V VDD range handles 24 V industrial bus power when paired with a simple linear regulator. With 3.5 KB Flash, firmware can store debounce routines, multi-channel event counting, and Modbus-RTU framing on the USART for SCADA integration. The -40 °C to +85 °C industrial grade handles factory-floor thermal ranges.
Recommended
Battery Charger CC/CV Profiles
Linear and switch-mode battery chargers benefit from the PIC16F677-I/SS as a state-machine controller, using its ADC to read charge-current sense resistors and battery voltage, while the ECCP module drives the charger MOSFET. The 2.0–5.5 V VDD range suits 1S Li-ion (4.2 V) and 4S NiMH (4.8 V) chemistries. The 128-byte EEPROM stores chemistry-specific CC/CV setpoints and end-of-charge thresholds. Compared to a dedicated charger IC, the PIC16F677 gives designers full flexibility for custom charge profiles, including LiFePO4 and NiZn chemistries. The -40 °C to +85 °C range covers most charging environments.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F677-I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F677T-I/SS | PIC16F677-E/SS | PIC16F690-I/SS | PIC16F676-I/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-SSOP (5.30mm) | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same |
| Program Memory (Flash) | 3.5 KB | 3.5 KB | 3.5 KB | 7 KB | 1.75 KB |
| Data EEPROM | 128 bytes | 128 bytes | 128 bytes | 256 bytes | 128 bytes |
| Maximum CPU Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| Digital I/O Pins | 18 | 18 | 18 | 18 | 12 |
| ADC Channels | 12 x 10-bit | 12 x 10-bit | 12 x 10-bit | 12 x 10-bit | 8 x 10-bit |
| Operating Temperature | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C | -40 °C to +125 °C (Extended) | -40 °C to +85 °C | -40 °C to +85 °C |
Key Differentiators
- Widest ADC channel count in 20-SSOP PIC16F sub-family (vs PIC16F676-I/SS)
- Larger Flash with same footprint vs PIC16F676 (vs PIC16F676-I/SS)
- Extended-temperature variant available on same package (vs PIC16F677-I/SS (this product))
- Industrial temp grade (-40 °C to +85 °C) matches most embedded use cases (vs PIC16F677-E/SS)
Design Notes
Decouple VDD with a 0.1 µF X7R ceramic capacitor placed within 5 mm of pin 20 with a short, wide trace to pin 19 (VSS). For noisy 24 V industrial rails or USB-derived 5 V supplies, add a 10 µF tantalum or aluminum polymer bulk capacitor at the regulator output. The PIC16F677 has separate digital (VDD) and ADC voltage pins on some variants - on the 20-pin SSOP, ADC reference is taken from VDD, so a clean supply directly improves ADC accuracy. Brown-out reset (BOR) should be enabled in configuration bits for unattended industrial deployments.
Keep the 20-SSOP footprint clear of high-current switching traces; the SSOP's 0.65 mm pitch requires adequate solder mask sliver (≥0.2 mm) and IPC-7351-compliant land patterns for reliable reflow. For production designs, add a 0.1 µF cap adjacent to /MCLR (pin 1) and a 10 kΩ pull-up to VDD unless a manual reset circuit or pushbutton is desired. Trace the ICSPDAT (pin 2) and ICSPCLK (pin 3) lines with 0.2 mm clearance and avoid running them parallel to switching-power traces for >5 mm to prevent programming glitches.
Always set the configuration bits correctly before code commits: oscillator selection (INTOSC vs HS vs XT), watchdog timer enable, code-protect bits, and BOR voltage threshold. A common pitfall is leaving the PIC in HS oscillator mode when no external crystal is fitted, which causes a non-functional device. The 35-instruction set is not fully orthogonal - read-modify-write on PORT registers (BSF/BCF on PORTB/PORTA) can cause bit glitches; use the LATCH register (LATx) for read-modify-write operations on output ports to avoid this documented erratum.
Compliance Information
RoHS compliant per Microchip product page. Industrial temperature grade -40 °C to +85 °C. Not AEC-Q100 qualified - choose PIC16F677T-I/SS automotive-grade screening for AEC-Q100 equivalent applications or consult Microchip for PPAP support.
