PIC16F631T-I/ML - 8-Bit MCU, 20MHz, 1.75KB Flash | Microchip
MPN: PIC16F631T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.96 | $0.96 |
| 10 | $0.89 | $8.90 |
| 100 | $0.83 | $83.00 |
| 500 | $0.77 | $385.00 |
| 1,000 | $0.7 | $700.00 |
PIC16F631T-I/ML Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (Flash/ROM), data memory (RAM), and programmable I/O peripherals on one silicon die. Microcontrollers sit at the bottom of the embedded computing hierarchy (MCU -> embedded processor -> microprocessor -> CPU) and are designed for deterministic, low-power, real-time control tasks. The PIC16F631 belongs to Microchip's well-established mid-range PIC® architecture (often called "mid-range x14"), meaning its instruction width is 14 bits and its core delivers predictable execution timing suitable for direct hardware control.
Key features of the PIC16F631T-I/ML include 128 bytes of EEPROM data memory, 11 general-purpose digital I/O pins, an integrated analog comparator, and Microchip's nanoWatt™ power-management technology for ultra-low standby current. The device supports in-circuit serial programming (ICSP) and in-circuit debugging (ICD), so firmware can be updated and debugged without removing the part from the board. The wide 2.0V to 5.5V operating range lets the device run directly from battery sources, regulated 3.3V rails, or 5V supplies, simplifying analog signal-chain interfaces.
Typical applications include low-cost consumer appliances, sensor-interface front-ends, battery-powered remote controls, LED lighting controllers, and small industrial control modules. The QFN-20 (4x4) footprint suits space-constrained surface-mount designs where a DIP or SOIC would be too tall or too large.
When designing with the PIC16F631, ensure that the exposed thermal pad is properly soldered to a sufficient copper pour (per Microchip layout guidelines) to meet thermal and electrical performance. The "T" suffix indicates tape-and-reel packaging and "I" denotes the industrial -40°C to +85°C temperature range, making the part suitable for harsh-environment deployment.
This page synthesizes real-time distributor pricing, qualified drop-in alternatives (same QFN-20 footprint), and design notes that are not bundled in the manufacturer datasheet, so engineers can make sourcing and substitution decisions in one place.
Drop-in alternatives for PIC16F631T-I/ML — 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 PIC16F631T-I/ML (same form factor and footprint) — differing in Package, Data EEPROM, I/O Pins, RoHS Status, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F631-I/ML
✅ Drop-In✓ In Stock
$0.74 / Unit
View Datasheet →PIC16F631-E/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F685-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F689-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F690-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F630T-E/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F631T-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 (mid-range x14) |
| Data Bus Width | 8-bit |
| CPU Frequency (Max) | 20 MHz |
| Program Memory (Flash) | 1.75 KB (1K x 14) |
| Data RAM | 64 bytes |
| Data EEPROM | 128 bytes |
| Operating Voltage Range | 2.0 V to 5.5 V |
| I/O Pins | 11 |
| Package | 20-QFN (4x4 mm) with EP |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40 °C to +85 °C (Industrial) |
| Packaging | Tape & Reel (T suffix) |
| Programming/Debug | ICSP + ICD |
| RoHS Status | Compliant |
| Lifecycle Stage | ACTIVE |
PIC16F631T-I/ML Pin Configuration
| Pin 1 | RA0/AN0/C1IN+ — Bidirectional I/O; analog input; comparator non-inverting input |
| Pin 2 | RA1/AN1/C1IN0- — Bidirectional I/O; analog input; comparator inverting input 0 |
| Pin 3 | RA2/AN2 — Bidirectional I/O; analog input |
| Pin 4 | RA3/MCLR/VPP — Bidirectional I/O; Master Clear (active-low reset); programming voltage input |
| Pin 5 | RA4/AN3/C1OUT — Bidirectional I/O; analog input; comparator output |
| Pin 6 | RA5/AN4/C2IN+/T1CKI — Bidirectional I/O; analog input; comparator non-inverting input; Timer1 clock input |
| Pin 7 | VSS — Ground reference |
| Pin 8 | RA7/OSC1/CLKIN — Bidirectional I/O; crystal oscillator input; external clock input |
| Pin 9 | RA6/OSC2/CLKOUT — Bidirectional I/O; crystal oscillator output; clock output |
| Pin 10 | RC0 — Bidirectional digital I/O |
| Pin 11 | RC1 — Bidirectional digital I/O |
| Pin 12 | RC2 — Bidirectional digital I/O |
| Pin 13 | RC3 — Bidirectional digital I/O |
| Pin 14 | RC4 — Bidirectional digital I/O |
| Pin 15 | RC5 — Bidirectional digital I/O |
| Pin 16 | RC6 — Bidirectional digital I/O |
| Pin 17 | RC7 — Bidirectional digital I/O |
| Pin 18 | VSS (EP) — Ground reference (also exposed thermal pad) |
| Pin 19 | VDD — Positive supply voltage (2.0V to 5.5V) |
| Pin 20 | NC — Not connected (per datasheet) |
Typical Applications
PIC16F631T-I/ML is suitable for 6 applications: Battery-Powered Sensor Front-End, Consumer Remote Control / IR Transmitter, LED Lighting Controller (PWM/Dimming), Industrial Control Module (PLCs, Sensors), Small Appliance Control Board, Automotive Aftermarket Accessories.
Battery-Powered Sensor Front-End
The PIC16F631T-I/ML fits battery-powered sensor front-ends because its 2.0V to 5.5V operating range lets it run directly from a single Li-ion cell or two alkaline cells, while its nanoWatt™ power-management technology reduces standby current to the microamp range. The integrated analog comparator and 11 digital I/O support direct interface to thermistors, PIR motion sensors, and reed switches without external op-amps. With 1.75KB Flash and 128B EEPROM, the part comfortably runs typical interrupt-driven sensor-firmware patterns including debouncing, periodic wake-and-measure cycles, and low-duty-cycle RF reporting. Compared to switching regulators, the MCU itself draws negligible quiescent current, preserving battery life across multi-year deployments in wireless sensor nodes and smart thermostats.
Recommended
Consumer Remote Control / IR Transmitter
The PIC16F631T-I/ML suits consumer IR remote controls because its 20MHz core executes the 38 kHz carrier generation and protocol timing via hardware interrupts with deterministic jitter, and its 1.75KB Flash holds common protocols like RC-5, NEC, and SIRC. The wide 2.0-5.5V supply range accepts two AAA cells directly, eliminating boost converters and saving BOM cost. With 11 I/O pins available, the MCU drives an LED, a few tactile buttons, and indicator LEDs with plenty of headroom. Compared to discrete 555-timer-based IR transmitters, the integrated solution cuts component count and enables firmware-defined protocol switching for universal remotes.
Recommended
LED Lighting Controller (PWM/Dimming)
The PIC16F631T-I/ML fits entry-level LED lighting controllers thanks to its 11 GPIO pins that can drive MOSFET gates or constant-current LED driver enable lines through PWM-like bit-banged patterns at 20 MHz. The 128-byte EEPROM stores dimming presets and color-mix coefficients that survive power cycles, while the integrated analog comparator enables closed-loop current sensing without an external op-amp. Operating from 2.0-5.5V, it accepts a regulated 3.3V or 5V rail with wide tolerance. For higher-end designs requiring true hardware PWM or 10-bit dimming resolution, the pin-compatible PIC16F690-I/ML adds enhanced PWM and a 10-bit ADC at the same QFN-20 footprint.
Recommended
Industrial Control Module (PLCs, Sensors)
The PIC16F631T-I/ML is suitable for compact industrial control modules because its -40°C to +85°C industrial temperature range supports factory-floor and outdoor-enclosure deployments. The 2.0V to 5.5V supply tolerates 24V-bus-derived rails after regulation, simplifying integration with industrial sensor stacks. The analog comparator and 11 GPIO handle dry-contact inputs, optocoupler interfaces, and small relay drivers. The ICSP/ICD interface allows field firmware updates and rapid prototype debugging without removing the MCU. For harsh-environment extensions, the PIC16F631-E/ML (extended -40°C to +125°C) is a same-footprint upgrade with identical electrical behavior.
Recommended
Small Appliance Control Board
The PIC16F631T-I/ML is well-matched to small home appliances such as coffee makers, fans, and air purifiers where a tiny QFN-20 footprint saves PCB area and 1.75KB of Flash holds a full user-interface state machine (button handling, mode selection, buzzer patterns, timer logic). The 11 GPIO pins handle button matrices, LED indicators, triac gate drivers, and tachometer inputs from fans, all from a single MCU. The wide 2.0-5.5V supply accepts rectified mains-derived rails comfortably. Compared to dedicated timer ICs, the programmable approach lets OEMs re-skin the user interface for multiple SKUs without changing the PCB.
Recommended
Automotive Aftermarket Accessories
The PIC16F631T-I/ML fits automotive aftermarket accessories such as alarm key fobs, interior LED modules, and simple sensor-driven displays because its 2.0-5.5V supply matches 12V-derived automotive rails after regulation, and its small QFN-20 footprint fits inside tight enclosures behind dashboards. The nanoWatt™ low-power modes suit always-on accessories where quiescent current must stay below 100 µA to avoid battery drain. Although the part itself is not AEC-Q100 qualified, it is widely used in non-safety aftermarket accessories (dashcams, lighting controllers, alarm remotes) where industrial-grade temperature tolerance is sufficient. For safety-critical or under-hood applications, AEC-Q100-qualified PIC16F variants from Microchip are recommended.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F631T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F631-I/ML | PIC16F685-I/ML | PIC16F689-I/ML | PIC16F690-I/ML |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-QFN (4x4) | 20-QFN (4x4) - same | 20-QFN (4x4) - same | 20-QFN (4x4) - same | 20-QFN (4x4) - same |
| CPU Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Program Flash | 1.75 KB | 1.75 KB | 2 KB | 4 KB | 7 KB |
| RAM | 64 B | 64 B | 64 B | 128 B | 256 B |
| EEPROM | 128 B | 128 B | 128 B | 256 B | 256 B |
| I/O Pins | 11 | 11 | 11 | 11 | 15 |
| Operating Voltage | 2.0V to 5.5V | 2.0V to 5.5V | 2.0V to 5.5V | 2.0V to 5.5V | 2.0V to 5.5V |
| ADC | None | None | 8-bit ADC | 12-bit ADC | 10-bit ADC |
| Operating Temperature | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C |
Key Differentiators
- Smallest Flash size and lowest cost in the PIC16F6xx QFN-20 family (vs PIC16F690-I/ML)
- No ADC integrated - simpler analog signal chain (vs PIC16F685-I/ML)
- Industrial-grade temperature range with low-power nanoWatt™ technology (vs PIC16F630T-E/ML)
Design Notes
The 20-QFN (4x4 mm) package has an exposed thermal pad (EP) on pin 18 that doubles as the primary ground connection. Per Microchip QFN layout guidelines, the EP must be soldered to a PCB pad with a thermal via array (typically 4-9 vias) connected to the ground plane to meet electrical performance and thermal ratings. Failing to solder the EP can cause high-current ground bounce, ESD sensitivity, and thermal derating issues.
Place a 100 nF decoupling capacitor as close as possible to the VDD pin (pin 19), with a 10 µF bulk capacitor on the same supply rail. For battery-powered designs, leverage the PIC16F631's nanoWatt™ sleep mode (typical < 1 µA standby) by switching off peripheral clocks and enabling the Watchdog Timer (WDT) for periodic wake-and-sample cycles. Use weak pull-ups on MCLR (pin 4) to allow in-circuit reset without spurious triggering during EMI events.
Ensure MCLR (pin 4) is not left floating - even a 10 kΩ internal MCLR reset configuration requires an external RC delay for reliable brownout recovery. When using the ICSP header, add 4.7 kΩ isolation resistors on PGC/PGD to prevent programming-interface contention with application circuitry. The analog comparator outputs are NOT open-drain on this device; verify sink/source capability against your driving load before omitting a buffer transistor.
Compliance Information
RoHS compliant per Microchip product page; not AEC-Q100 qualified (use AEC-Q100 PIC16F variants for automotive safety-critical designs)
