PIC16F631-I/ML - 8-Bit 20MHz 1.75KB Flash MCU | Microchip QFN-20
MPN: PIC16F631-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.65 | $1.65 |
| 10 | $1.42 | $14.20 |
| 100 | $1.18 | $118.00 |
| 500 | $0.99 | $495.00 |
| 1,000 | $0.86 | $860.00 |
| 3,000 | $0.74 | $2,220.00 |
PIC16F631-I/ML Overview
A microcontroller (MCU) is a single-chip computer containing a processor core, program and data memory, and programmable I/O peripherals. The PIC16F631 belongs to the mid-range (x14 instruction word) PIC® family, which balances code density, peripheral integration, and low power consumption. Within the broader semiconductor hierarchy, this part sits at: 8-bit microcontroller -> microcontroller -> embedded processor -> integrated circuit -> semiconductor. This taxonomy matters because engineers selecting the PIC16F631 are typically targeting low-cost, low-power applications where 32-bit performance is unnecessary.
Key differentiating features include nanoWatt Technology power management with multiple sleep modes (typical standby current below 1 µA), an integrated analog comparator with programmable reference, and on-chip EEPROM for non-volatile data storage. The 20 MHz oscillator delivers 5 MIPS of throughput, adequate for sensor conditioning, user-interface scanning, and basic communication tasks. The part also includes in-circuit serial programming (ICSP) for field updates.
The PIC16F631 uses a modified Harvard RISC architecture with a 14-bit instruction word and 8-bit data path, allowing deterministic instruction timing and compact code density. Its internal 8 MHz oscillator is factory calibrated to ±1 %, and an optional 31 kHz low-power oscillator supports real-time-clock-like operation. Hardware multipliers are absent — designers use software routines for arithmetic beyond simple addition/subtraction.
Typical applications include home-appliance control, battery-powered sensor nodes, low-end remote controls, and consumer electronics subsystems requiring analog sensing and PWM outputs. The integrated analog comparator makes the device suitable for threshold detection (e.g., battery monitors, light sensors) without external op-amps.
When designing with the PIC16F631-I/ML, ensure decoupling of VDD with a 100 nF ceramic capacitor placed within 2 mm of the package pin. For QFN-20 (4x4), expose the thermal pad to a grounded copper pour to aid thermal dissipation; this pad is internally connected to VSS. Consider using the internal oscillator to reduce BOM cost when ±1 % frequency accuracy is acceptable.
This page consolidates distributor pricing, drop-in compatible alternatives, and practical QFN-20 layout guidance that complements — but does not replace — the official Microchip datasheet (document number 41287D per the manufacturer product page).
Drop-in alternatives for PIC16F631-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 PIC16F631-I/ML (same form factor and footprint) — differing in Core Architecture, Data EEPROM, I/O Pins, Package, Data RAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F630-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F677-I/ML
✅ Drop-In✓ In Stock
$1.42 / Unit
View Datasheet →PIC16F685-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F687-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)
PIC16F631-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit (mid-range x14) |
| Program Memory (Flash) | 1.75 KB (1K x 14) |
| Data RAM | 128 bytes |
| Data EEPROM | 64 bytes |
| Maximum CPU Clock | 20 MHz |
| Instruction Throughput | 5 MIPS |
| Supply Voltage (VDD) | 2.0 V to 5.5 V (industrial: 4.5 V to 5.5 V) |
| I/O Pins | 11 (bidirectional) |
| ADC | None (no on-chip ADC per PIC16F631 datasheet family overview) |
| Comparators | 2 (on-chip, with programmable reference) |
| Timers | 1 x 8-bit, 1 x 16-bit |
| PWM / CCP Modules | Enhanced CCP (1x ECCP) + 1x CCP |
| Internal Oscillator | 8 MHz factory-calibrated (typical ±1 %) |
| Low-Power Oscillator | 31 kHz LFINTOSC |
| Operating Temperature (Industrial) | -40 °C to +85 °C |
| Package | 20-pin QFN (4 x 4 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited floor life) |
| RoHS Status | Compliant |
| Programming Interface | ICSP (In-Circuit Serial Programming) |
| Low-Power Mode (nanoWatt) | Typical standby current < 1 µA |
PIC16F631-I/ML Pin Configuration
| Pin 1 | RA0/AN0/C1IN+/ICSPDAT — GPIO RA0 / analog input 0 / comparator 1 non-inverting input / ICSP data |
| Pin 2 | RA1/AN1/C1IN-/ICSPCLK — GPIO RA1 / analog input 1 / comparator 1 inverting input / ICSP clock |
| Pin 3 | RA2/AN2/CVREF/C1OUT — GPIO RA2 / analog input 2 / comparator voltage reference output / comparator 1 output |
| Pin 4 | RA3/MCLR/VPP — GPIO RA3 / master clear reset (active low) / programming voltage |
| Pin 5 | RA4/AN3/T0CKI/C2OUT — GPIO RA4 / analog input 3 / Timer0 clock input / comparator 2 output |
| Pin 6 | RA5/AN4/SS/HLVDIN/C2IN+ — GPIO RA5 / analog input 4 / SPI slave select / high/low voltage detect / comparator 2 non-inverting input |
| Pin 7 | VSS — Ground reference |
| Pin 8 | OSC1/RA7/CLKIN — External oscillator input / GPIO RA7 / external clock input |
| Pin 9 | OSC2/RA6/CLKOUT — External oscillator output / GPIO RA6 / clock output |
| Pin 10 | RC0 — GPIO RC0 |
| Pin 11 | RC1 — GPIO RC1 |
| Pin 12 | RC2/P1A/CCP1 — GPIO RC2 / PWM output P1A / CCP1 output |
| Pin 13 | RC3/P1B/CCP2 — GPIO RC3 / PWM output P1B / CCP2 output |
| Pin 14 | RC4 — GPIO RC4 |
| Pin 15 | RC5 — GPIO RC5 |
| Pin 16 | RC6 — GPIO RC6 |
| Pin 17 | RC7 — GPIO RC7 |
| Pin 18 | VDD — Positive supply voltage (2.0 V to 5.5 V) |
| Pin 19 | VSS — Ground reference (second pad for QFN) |
| Pin 20 | RB4 — GPIO RB4 |
Typical Applications
PIC16F631-I/ML is suitable for 7 applications: Battery-Powered Sensor Node, Home Appliance Control Board, IR Remote Control Transmitter, Capacitive Touch / Proximity Detector, LED Lighting Controller, Battery Charger / Monitor, Automotive Interior Accessory (Non-Safety).
Battery-Powered Sensor Node
The PIC16F631-I/ML is well matched to battery-powered sensor nodes thanks to its nanoWatt Technology standby current below 1 µA and 2.0-5.5 V supply range covering single-cell lithium and dual-AA chemistries. The 20 MHz CPU provides 5 MIPS — adequate for periodic sensor reads, threshold checks against the on-chip analog comparators, and short RF packet formatting. Designers typically duty-cycle the MCU at <1 % active time, holding sleep current below the self-discharge rate of the battery. The 20-pin QFN footprint and internal 8 MHz oscillator eliminate the external crystal BOM, shrinking PCB area and quiescent draw simultaneously.
Recommended
Home Appliance Control Board
In home-appliance subsystems — small kitchen appliances, washing-machine user interfaces, thermostat front-ends — the PIC16F631-I/ML provides 11 GPIO pins for keypad scanning, LED driving, and relay/triac interface. Its two on-chip comparators handle line-voltage zero-cross detection and over-temperature sensing without external op-amps. The 1.75 KB flash is sufficient for state-machine control firmware, while 64 bytes of EEPROM allows last-mode memory after power loss. Industrial -40 to +85 °C operation supports unheated garage or laundry-room installations.
Recommended
IR Remote Control Transmitter
Low-end IR remote controls benefit from the PIC16F631-I/ML's low cost, small footprint, and ultra-low standby current. The 20 MHz clock easily generates 36-40 kHz carrier frequencies for NEC or RC5 protocols via PWM, and the ECCP module can drive an IR LED directly with appropriate current-limiting. Battery-life extension is critical — nanoWatt sleep mode draws well under 1 µA when the device is idle, allowing a single CR2032 coin cell to power a remote for years. The 20-pin QFN (4x4) package fits inside slim remote housings.
Recommended
Capacitive Touch / Proximity Detector
The PIC16F631-I/ML's two on-chip analog comparators can be configured with the CTMU (Charge Time Measurement Unit) for basic capacitive touch sensing on a few keys without an external touch controller. The internal comparators handle proximity wake-up, allowing the MCU to remain in deep sleep until the user approaches, then wake within microseconds to scan the touch pads. Combined with the wide 2.0-5.5 V supply range, this makes the part a cost-effective touch UI for consumer devices like small appliances and toys.
Recommended
LED Lighting Controller
The PIC16F631-I/ML drives single or multi-channel LED lighting via its PWM-capable ECCP module, supporting dimming and color-mixing routines for strip lights or decorative fixtures. The internal 8 MHz oscillator is accurate enough for stable PWM duty cycles without external timing components. The comparators enable zero-current detection in buck-driver topologies, while 64 bytes of EEPROM store last brightness setting across power cycles. Industrial temperature grading permits outdoor lighting enclosures.
Recommended
Battery Charger / Monitor
For simple single-cell Li-ion charger controllers, the PIC16F631-I/ML monitors voltage and current through its two analog comparators, terminating charge at the 4.2 V cutoff without a dedicated charger IC. The 20 MHz clock supports CC-CV charging algorithms with software PWM, and 64 bytes of EEPROM log cycle count for warranty tracking. Note that the part lacks ADC, so the comparators provide threshold detection — designers needing continuous voltage measurement should select the PIC16F677 or PIC16F685 from the same family as a drop-in upgrade.
Recommended
Automotive Interior Accessory (Non-Safety)
For non-safety automotive interior accessories — interior lighting, simple climate-control keypads, accessory sockets — the PIC16F631-I/ML's industrial -40 to +85 °C range survives cabin environments. Designers must select the AEC-Q100 qualified PIC16F631T-I/ML for under-hood or safety-relevant applications; this standard -I part suits only non-critical cabin functions. The 2.0-5.5 V supply range handles 12 V battery drops during cranking via external regulation.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F631-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F630-I/ML | PIC16F677-I/ML | PIC16F685-I/ML | PIC16F690-I/ML |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | QFN-20 (4x4 mm) | QFN-20 (4x4 mm) - same | QFN-20 (4x4 mm) - same | QFN-20 (4x4 mm) - same | QFN-20 (4x4 mm) - same |
| Flash Program Memory | 1.75 KB (1K x 14) | 0.875 KB | 3.5 KB | 4 KB | 4 KB |
| Data RAM | 128 bytes | 64 bytes | 256 bytes | 256 bytes | 256 bytes |
| Data EEPROM | 64 bytes | 64 bytes | 256 bytes | 256 bytes | 256 bytes |
| On-chip ADC | None (comparators only) | None (comparators only) | 10-bit, 12 channels | 10-bit + 12-bit ADC | 10-bit, 12 channels |
| Comparators | 2 | 1 | 2 | 2 | 2 |
| Maximum Clock | 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 |
| Operating Temperature | -40 °C to +85 °C (industrial) | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
Key Differentiators
- Only 20-pin QFN family member optimized for pure comparator-based sensing without ADC overhead (vs PIC16F677-I/ML)
- Lower-cost entry point in the PIC16F6xx QFN-20 family (vs PIC16F690-I/ML)
- NanoWatt Technology with sub-µA standby current for battery-powered designs (vs PIC16F630-I/ML)
- Mid-range x14 architecture with deterministic 200 ns instruction cycle (vs PIC16F505-I/P (older baseline family))
Design Notes
Place a 100 nF ceramic decoupling capacitor within 2 mm of the VDD pin and a bulk 10 µF electrolytic or tantalum near the MCU for transient load support. For QFN-20 packages, the exposed thermal pad (EP) is internally bonded to VSS and must be soldered to a copper ground pour. Use a star-ground topology if the design mixes analog comparators with switching nodes. Add a 10 kΩ pull-up on MCLR (pin 4) to avoid spurious resets; use a Schottky diode from MCLR to VDD if in-circuit serial programming is required.
For the QFN-20 (4x4 mm) footprint, the central thermal pad requires at least 4 thermal vias (0.3 mm drill, 0.6 mm pad) to the inner ground plane for heat dissipation. Keep trace widths under the QFN to a minimum to preserve the ground-pour integrity. Maintain 0.2 mm clearance between QFN pads and any copper pour to prevent solder wicking during reflow. Land pattern recommendations follow IPC-7351 nominal-density profiles. Place the crystal (if used) within 5 mm of OSC1/OSC2 to minimize parasitic capacitance.
Estimated: With 20 MHz external clock at 5 V VDD, ICC peaks around 11 mA active. Do not assume the internal 8 MHz oscillator matches an external crystal's frequency under all conditions — recalibrate after enabling the PLL or switching oscillator modes. Do not enable the weak pull-ups on RA3/MCLR; this pin requires a dedicated external pull-up. Avoid driving the analog comparators above VDD or below VSS to prevent ESD latch-up. When migrating code from PIC16F630 to PIC16F631, verify that comparator 2 registers are configured correctly — only one comparator exists on the F630.
Keep analog comparator input traces short and routed away from PWM outputs (RC2/RC3) to avoid coupling. Use a guard ring around the comparator input pad when sensing high-impedance analog signals. If the CTMU is used for capacitive touch, route the charge/discharge traces with constant geometry and use a ground flood on adjacent layers to minimize leakage. The internal comparators have a typical input offset of ±5 mV — adequate for threshold sensing but not for precision measurement (consider PIC16F677 with 10-bit ADC for higher accuracy).
Compliance Information
RoHS compliant and lead-free per Microchip product page (ML suffix indicates lead-free QFN package). Industrial -I temperature grade covers -40 °C to +85 °C but is NOT AEC-Q100 qualified for automotive safety applications. For AEC-Q100 needs, select an automotive-qualified PIC16F631 variant or consult Microchip's automotive-grade product portfolio.
