PIC16F631-E/SS - 8-bit MCU 1.75KB Flash 20MHz SSOP-20 | Microchip
MPN: PIC16F631-E/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.66 | $16.60 |
| 100 | $1.48 | $148.00 |
| 500 | $1.32 | $660.00 |
| 1,000 | $1.18 | $1,180.00 |
PIC16F631-E/SS Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program and data memory, peripherals, and I/O on one silicon die. The PIC16F631 belongs to the low pin-count (20-pin) PIC family, which sits in the taxonomy microcontroller -> embedded processor -> digital IC -> semiconductor. Microchip's mid-range x14 core delivers deterministic, single-cycle instruction execution at 200 ns per instruction at 20 MHz, simplifying real-time control loops for entry-level and cost-sensitive applications.
Key features of the PIC16F631-E/SS include nanoWatt technology for ultra-low power consumption, 18 general-purpose I/O pins, an internal 8 MHz oscillator, an enhanced capture/compare/PWM (ECCP) module, multiple timers (Timer0, Timer1, Timer2), a 10-bit ADC, comparators, and on-chip EEPROM for non-volatile data storage. The extended (-E) temperature grade is qualified to -40C to +125C, suitable for industrial, automotive aftermarket, and outdoor applications.
Internally, the PIC16F631 uses a Harvard architecture with separate program and data buses, which allows instruction fetch and data access in the same clock cycle. Its 14-bit instruction word provides compact code density, and the Flash memory supports in-circuit serial programming (ICSP) for easy field updates.
Typical applications include consumer appliances, sensor interfacing nodes, LED drivers, low-end motor control, battery chargers, security panels, and industrial control logic. It is also widely used in educational and hobbyist platforms because of its simplicity, low cost, and robust toolchain support (MPLAB X IDE + XC8 compiler + PICkit programmer).
When designing with the PIC16F631-E/SS, ensure decoupling capacitors (100 nF plus a bulk 10 uF) are placed close to VDD and VSS, and respect the 5.5 V absolute maximum on VDD to avoid latch-up. Use the internal 8 MHz oscillator to reduce BOM cost unless precise timing is required; otherwise, an external crystal up to 20 MHz is recommended for UART and timing-critical peripherals.
This page consolidates distributor pricing, SSOP-20 drop-in alternatives, and practical design notes not all available from a single datasheet source, giving engineers a faster, more informed selection workflow.
Drop-in alternatives for PIC16F631-E/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 PIC16F631-E/SS (same form factor and footprint) — differing in Package, I/O Pins, Timers, ADC, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F631-I/SS
✅ Drop-In✓ In Stock
$1.45 / Unit
View Datasheet →PIC16F630-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F630T-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F631-E/SO
✅ Drop-In✓ In Stock
$0.5927 / Unit
View Datasheet →PIC16F628AT-E/SS
✅ Drop-In✓ In Stock
$1.98 / Unit
View Datasheet →PIC16F631-E/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC mid-range 8-bit (x14 instruction word) |
| Program Memory (Flash) | 1.75 KB (1K x 14) |
| EEPROM Data Memory | 128 bytes |
| SRAM | 64 bytes |
| Maximum CPU Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns @ 20 MHz |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| I/O Pins | 18 |
| ADC | 10-bit |
| Timers | Timer0, Timer1, Timer2 |
| ECCP Module | 1 (Enhanced Capture/Compare/PWM) |
| Comparators | 2 |
| Internal Oscillator | 8 MHz (factory calibrated) |
| Operating Temperature (Extended) | -40 C to +125 C |
| Package | 20-pin SSOP |
| Mounting Type | Surface Mount |
| nanoWatt Power Management | Yes |
| In-Circuit Serial Programming | Yes (ICSP) |
| RoHS Status | Compliant |
PIC16F631-E/SS Pin Configuration
| Pin 1 | VDD — Positive supply voltage |
| Pin 2 | RA5/T1CKI/OSC1/CLKIN — GPIO RA5 / Timer1 clock input / external clock input |
| Pin 3 | RA4/T1G/OSC2/CLKOUT — GPIO RA4 / Timer1 gate / external clock output |
| Pin 4 | RA3/MCLR/VPP — GPIO RA3 / Master Clear (reset) / programming voltage |
| Pin 5 | RC5 — GPIO RC5 |
| Pin 6 | RC4 — GPIO RC4 |
| Pin 7 | RC3/CCP1 — GPIO RC3 / CCP1 PWM output |
| Pin 8 | RC6 — GPIO RC6 |
| Pin 9 | RC7 — GPIO RC7 |
| Pin 10 | RB7 — GPIO RB7 |
| Pin 11 | RB6 — GPIO RB6 |
| Pin 12 | RB5 — GPIO RB5 |
| Pin 13 | RB4 — GPIO RB4 |
| Pin 14 | RC2/AN10 — GPIO RC2 / analog input AN10 |
| Pin 15 | RC1/AN8 — GPIO RC1 / analog input AN8 |
| Pin 16 | RC0/AN4 — GPIO RC0 / analog input AN4 |
| Pin 17 | RA2/AN2 — GPIO RA2 / analog input AN2 |
| Pin 18 | RA1/AN1 — GPIO RA1 / analog input AN1 / ICSPCLK |
| Pin 19 | RA0/AN0 — GPIO RA0 / analog input AN0 / ICSPDAT |
| Pin 20 | VSS — Ground reference |
Typical Applications
PIC16F631-E/SS is suitable for 6 applications: Consumer Appliance Control, Battery-Powered Sensor Node, LED Lighting and Signage Drivers, Industrial Control Logic, Automotive Aftermarket Accessories, Educational and Hobbyist Development.
Consumer Appliance Control
The PIC16F631-E/SS fits appliance control boards because of its low cost, 18 GPIO, and Extended temperature grade. With 1.75 KB Flash, the firmware can drive a simple user interface, sense push-buttons and rotary encoders, and control relays or TRIACs through GPIO or PWM. The 10-bit ADC reads temperature sensors (NTC) and line voltage, while the ECCP module generates the zero-crossing timing needed for dimmer circuits. Operating from 2.0 to 5.5 V, the part can be powered directly from a 5 V regulator or from a rectified 3.3 V supply. Its nanoWatt sleep mode (down to a few hundred nA typical) makes it ideal for white goods that spend most of their life in standby.
Recommended
Battery-Powered Sensor Node
For wireless or wired sensor nodes running from a 3 V coin cell or two AA cells, the PIC16F631-E/SS delivers enough MIPS for periodic sensing while drawing only nanoWatts in sleep. Its 10-bit ADC reads thermistor, photocell, or gas-sensor analog outputs; the on-chip EEPROM (128 bytes) stores calibration constants without battery-backed SRAM. The internal 8 MHz oscillator eliminates an external crystal, reducing BOM and quiescent leakage. With 64 bytes of SRAM the firmware can buffer small packets before waking a companion RF IC such as the MRF24J40 over SPI. The Extended -E temp grade supports outdoor and cold-chain deployments.
Recommended
LED Lighting and Signage Drivers
In decorative LED strips, channel-letter signs, and architectural lighting, the PIC16F631-E/SS drives multiple LED strings via PWM using its ECCP module plus Timer2 for hardware PWM generation. The 10-bit PWM resolution (1024 steps) provides smooth dimming without flicker. The MCU's 5.5 V tolerance lets it interface directly to 5 V LED driver logic; the 18 GPIO can matrix up to 8x10 LED panels in a Charlieplexed arrangement. Internal EEPROM remembers brightness presets across power cycles, and nanoWatt sleep reduces idle current in always-on signage to a few hundred microamperes.
Recommended
Industrial Control Logic
Factory automation edge nodes (sensor conditioning, simple PLC replacement, machine-status indicators) commonly use the PIC16F631-E/SS because of its 5.5 V tolerance (directly interfaces to 24 V-referenced signal conditioning through external resistor dividers) and its Extended -40C to +125C temperature grade. The two on-chip comparators can implement window detectors and over-current protection without an external op-amp. 128 bytes of EEPROM store runtime counters and fault logs that survive brown-outs. Its deterministic mid-range core simplifies IEC 61508 SIL-1 functional-safety analysis compared with complex Cortex-M parts.
Recommended
Automotive Aftermarket Accessories
Aftermarket modules (alarm systems, gauge drivers, interior LED controllers, switch panels) routinely use the PIC16F631-E/SS. While not AEC-Q100 qualified, its Extended -40C to +125C grade handles automotive cabin and under-hood-adjacent thermal exposure for non-safety accessories. The hardware ECCP + Timer2 pair produces accurate PWM for motor speed or fan control, and the ADC reads fuel-level, temperature, or illumination sensors. The Flash-based ICSP interface allows field firmware updates via a 4-pin header, valuable for tuners and accessory installers.
Recommended
Educational and Hobbyist Development
The PIC16F631-E/SS is widely used in universities, vocational schools, and the maker community because of its low cost, robust PICkit programmer support, and abundant example code in MPLAB X and XC8. With 18 GPIO, students can wire up buttons, LEDs, character LCDs, and SPI/I2C peripherals without running out of pins. Its single-cycle 14-bit instruction set makes timing calculations and interrupt-latency analysis straightforward, building core embedded skills that transfer to larger PIC16 and PIC18 parts. SSOP-20 breakout boards are inexpensive and reusable across projects.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F631-E/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F631-I/SS | PIC16F630-I/SS | PIC16F630T-I/SS | PIC16F631-E/SO | PIC16F628AT-E/SS |
|---|---|---|---|---|---|---|
| Package | 20-pin SSOP | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SOIC - drop-in | 20-pin SSOP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory (Flash) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 3.5 KB (2K x 14) |
| EEPROM | 128 bytes | 128 bytes | 64 bytes (-50%) | 64 bytes (-50%) | 128 bytes | 128 bytes |
| I/O Pins | 18 | 18 | 12 (-33%) | 12 (-33%) | 18 | 16 (-11%) |
| Maximum Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating Temperature | -40 C to +125 C (Extended) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +125 C (Extended) | -40 C to +125 C (Extended) |
| 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 | 2.0 V to 5.5 V |
| Unit Price (qty 1, USD) | $1.85 | $1.65 approx | $1.55 approx | $1.55 approx | $1.85 approx | $2.40 approx |
Key Differentiators
- Extended -40C to +125C temperature grade (vs PIC16F631-I/SS)
- 18 GPIO with 10-bit ADC and 2 comparators (vs PIC16F630-I/SS)
- 128 bytes EEPROM for parameter storage (vs PIC16F630-I/SS)
Design Notes
Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of the VDD pin and a 10 uF bulk electrolytic or tantalum at the board supply entry. For battery-powered designs, the on-chip brown-out reset (BOR) and Power-on Reset (POR) eliminate the need for an external voltage supervisor; enable BOR in the configuration words at a threshold appropriate for your supply.
At 20 MHz from a 5 V supply, the PIC16F631-E/SS draws roughly 11 mA active. SSOP-20 has theta_JA around 90 C/W on a standard JEDEC 2S2P test board, giving a 1 C rise per 1 mW of dissipation. At typical 55 mW active load, junction rise over ambient is roughly 5 C - no heatsink required. In enclosed housings above 60 C ambient, derate the clock or enable nanoWatt sleep to keep junction below 150 C (SSOP rated to +125 C ambient with industrial margin).
Route MCLR through a 10 kohm pull-up to VDD; if used in a noisy environment, add a 100 nF capacitor from MCLR to VSS for hardware reset filtering. Place ICSP programming pins (RA0/ICSPDAT, RA1/ICSPCLK, MCLR/VPP) on accessible header pads to avoid rework during code development. SSOP-20 land pads should have 0.4 mm pitch with NSMD pads and a solder mask defined to reduce tombstoning during reflow.
Do not exceed 5.5 V on VDD or 8.5 V on MCLR (during ICSP) - both will trigger latch-up. The ECCP module pin must be configured as an output in the TRIS register before PWM can drive it, a common gotcha when porting code from PIC16F630 examples. If analog inputs share a pin with digital functions, set the corresponding ANSEL bit and disable the digital input buffer to save 3 uF of pin leakage that would otherwise corrupt ADC readings.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - not intended for OEM automotive safety-critical applications; use automotive-qualified PIC16F families for OEM automotive. Lead-free SSOP-20 packaging as of factory production.
