PIC12F509-I/SN - 8-Bit 4MHz MCU, 1.5KB Flash | Microchip
MPN: PIC12F509-I/SN ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.3 | $1.30 |
| 10 | $1.18 | $11.80 |
| 100 | $1.05 | $105.00 |
| 500 | $0.92 | $460.00 |
| 1,000 | $0.82 | $820.00 |
| 3,000 | $0.71 | $2,130.00 |
PIC12F509-I/SN Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory (Flash/ROM), working RAM, and configurable I/O peripherals. The PIC12F509 belongs to the 8-bit PIC10/12 baseline/enhanced mid-range hierarchy, sitting between the even smaller 6/8-pin PIC10F family and the 14/20-pin PIC16F family. Its 8-bit Harvard architecture with separate program and data buses allows single-cycle instruction execution, and its 12-bit wide instruction word delivers the typical 2:1 code compression over competitive 8-bit MCUs of its class.
Key features include an internal 4 MHz RC oscillator with calibrated accuracy of typically ±1%, six general-purpose digital I/O pins (one input-only GP3), one 8-bit timer/counter (Timer0), a watchdog timer with its own on-chip RC oscillator for reliable operation, and an in-circuit serial programming (ICSP) interface. The device supports a wide 2.0V to 5.5V operating voltage range and the industrial -40C to +85C temperature range, making it suitable for both battery-powered consumer products and harsh-environment embedded nodes.
The PIC12F509's power-on reset, brown-out detect, and code-protection features are all integrated on-chip, eliminating external reset supervisors. Its ultra-low power architecture typically draws less than 1 mA active at 4 MHz / 5V and only microamperes in sleep, qualifying it for energy-harvesting and always-on sensor applications.
Typical applications include battery-powered timer/sequencer modules, LED blinkers, replacement of discrete logic gates with software, simple sensor signal conditioning, low-end consumer appliances, and IoT edge-node controllers. The 8-pin SOIC footprint makes hand-soldering and breadboarding straightforward for hobbyists and rapid prototyping.
When designing with this part, allocate one I/O pin to MCLR (reset) if you need external reset, or leave it tied to VDD through a resistor for the internal reset configuration. The ICSP pins (GP1/GP0) are shared with GPIO, so plan your pinout to keep PGD/PGC available during in-circuit programming.
This page synthesizes distributor stock levels, drop-in SOIC-8 alternatives, and practical design notes not consolidated in the manufacturer datasheet alone, giving procurement and embedded engineers a single reference for evaluation, replacement, and board bring-up.
Drop-in alternatives for PIC12F509-I/SN — 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 PIC12F509-I/SN (same form factor and footprint) — differing in Package, Timers, Core Architecture, Watchdog Timer, Instruction Set.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12F509-I/P
✅ Drop-In✓ In Stock
$0.86 / Unit
View Datasheet →PIC12F509-I/MS
✅ Drop-In✓ In Stock
$0.51 / Unit
View Datasheet →PIC12F509T-I/SN
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F508-I/SN
✅ Drop-In✓ In Stock
$0.31 / Unit
View Datasheet →PIC12F509-E/SN
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12CE518-04E/SN
✅ Drop-In✓ In Stock
$1.38 / Unit
View Datasheet →PIC12F509-I/SN Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory | 1.5 KB Flash (1K x 12 words) |
| RAM | 41 bytes |
| Data EEPROM | 41 bytes |
| Maximum CPU Speed | 4 MHz |
| Instruction Set Width | 12-bit |
| Number of Instructions | 33 single-word/single-cycle |
| Operating Voltage Range | 2.0 V to 5.5 V |
| I/O Pins | 6 (5 GPIO + 1 input-only GP3) |
| Timers | 1 x 8-bit Timer0 with prescaler |
| Watchdog Timer | Yes, with dedicated on-chip RC oscillator |
| Internal Oscillator | 4 MHz RC, factory calibrated |
| Brown-out Reset | Yes |
| In-Circuit Programming | ICSP (2-wire) |
| Operating Temperature Range | -40 C to +85 C (Industrial) |
| Package | 8-pin SOIC (SN, 3.90 mm body) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| MSL Level | 1 |
PIC12F509-I/SN Pin Configuration
| Pin 1 | VDD — Positive supply voltage (+2.0 V to +5.5 V) |
| Pin 2 | GP5/OSC1/CLKIN — Bidirectional I/O pin / Timer1 clock input / external clock input |
| Pin 3 | GP4/OSC2/CLKOUT — Bidirectional I/O pin / oscillator output / clock output (Fosc/4) |
| Pin 4 | GP3/MCLR/VPP — Input-only GPIO / Master Clear reset (active low) / programming voltage input |
| Pin 5 | GP2/T0CKI/INT/COUT — Bidirectional I/O / Timer0 clock input / external interrupt / comparator output |
| Pin 6 | GP1/ICSPDAT — Bidirectional I/O / ICSP data line |
| Pin 7 | GP0/ICSPCLK — Bidirectional I/O / ICSP clock line |
| Pin 8 | VSS — Ground reference |
Typical Applications
PIC12F509-I/SN is suitable for 7 applications: Battery-Powered LED Blinker / Indicator, Logic-Gate Replacement / Glue Logic MCU, Simple Sensor Signal Conditioning, Consumer Appliance Timer / Sequencer, Toy and Hobby Electronics Controller, Automotive Accessory and Aftermarket Modules, IoT Edge Sensor Node (Simple Protocol).
Battery-Powered LED Blinker / Indicator
The PIC12F509-I/SN is purpose-built for battery-powered single-LED indicators where every microamp matters. Its 2.0 V to 5.5 V VDD range supports two-cell alkaline or coin-cell operation down to end-of-life voltage, while its 4 MHz internal RC oscillator eliminates the crystal, reducing BOM to just the MCU, the LED, and one current-limit resistor. Sleep current under 1 uA (watchdog disabled) yields years of life on a single CR2032. The 6 I/O pins are sufficient to drive an RGB status LED, a pushbutton, and an optional buzzer, with GP3 reserved as the wake-up input on interrupt edge.
Recommended
Logic-Gate Replacement / Glue Logic MCU
When discrete 74HC logic becomes too bulky or power-hungry, the PIC12F509-I/SN replaces 2-4 logic gates with a single 8-pin MCU, executing the equivalent boolean logic in software at 4 MIPS. Its 33 single-cycle instructions fit within the 1.5 KB Flash for typical combinational and sequential glue functions such as debouncing, multiplexing, edge-detection, and short protocol bridges. The wide 2.0-5.5 V VDD range means it can straddle 3.3 V and 5 V logic domains without level shifters, and the ICSP pins (GP0/GP1) double as general I/O when not programming.
Recommended
Simple Sensor Signal Conditioning
The PIC12F509-I/SN is widely used as a low-cost sensor front-end MCU that reads a single analog sensor via GP2's T0CKI comparator mode or digital sensor via the GPIO pins, then drives a relay, MOSFET, or PWM output. Its 8-bit Timer0 with programmable prescaler enables precise event timing for pulse counting, duty-cycle measurement, and frequency-to-digital conversion. Operating down to 2.0 V lets it run directly from solar cells or thermoelectric harvesters without a boost converter, while brown-out reset prevents undefined behavior during brown-out events.
Recommended
Consumer Appliance Timer / Sequencer
In small consumer appliances (coffee makers, humidifiers, air fresheners), the PIC12F509-I/SN serves as a cost-optimized timer/sequencer that drives relays or TRIACs in a fixed on/off pattern. Its Timer0 with prescaler can generate minute- or hour-scale delays from the internal 4 MHz oscillator, and the watchdog timer provides automatic recovery from brown-outs or ESD-induced lockups. The industrial -40 C to +85 C temperature rating covers kitchen and bathroom environments, and the small 8-pin SOIC simplifies EMC-compliant PCB layout.
Recommended
Toy and Hobby Electronics Controller
The PIC12F509-I/SN is a staple of hobby electronics, RC servos, and educational kits because of its sub-$1 price, hand-solderable SOIC-8 footprint, and free MPLAB X IDE + XC8 toolchain. Six I/O pins can drive two hobby servos via Timer0 PWM, or read up to 4 buttons plus an I2C peripheral on GP0/GP1. Its 4 MIPS performance is more than enough to bit-bang UART, software I2C, or WS2812 NeoPixel protocols at low LED counts, making it a teaching-grade introduction to embedded C and assembly programming.
Recommended
Automotive Accessory and Aftermarket Modules
For non-safety automotive accessories (LED accent lighting, dome-light delays, switch-panel controllers), the PIC12F509-I/SN provides a low-cost MCU in a tiny 8-pin SOIC. Its 2.0-5.5 V range is compatible with 12 V battery systems after a simple 5 V LDO regulator, and its -40 C to +85 C industrial range covers cabin environments. While not AEC-Q100 qualified (the PIC12F509T-I/SN automotive variant or PIC16F15313 should be used for under-hood applications), it remains a popular choice for interior aftermarket modules where cost dominates over qualification.
Recommended
IoT Edge Sensor Node (Simple Protocol)
In minimalist IoT edge nodes (window/door contact sensors, soil-moisture probes, leak detectors), the PIC12F509-I/SN acts as a wake-up MCU that reads one digital sensor and wakes a more powerful BLE/LoRa SoC only when an event occurs. Sleep currents below 1 uA (watchdog off) yield multi-year coin-cell life, and the 33-instruction RISC core is sufficient for sensor debouncing and one-wire-style bit-banging. Its ICSP pins (GP0/GP1) double as GPIO for the radio module's serial interface, avoiding any pin multiplexing.
Recommended
Recommended Products Summary
Engineering reference data for PIC12F509-I/SN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12F509-I/P | PIC12F509-I/MS | PIC12F508-I/SN | PIC12F509-E/SN | PIC12CE518-04E/SN |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-SOIC (SN) | PDIP-8 (through-hole, different footprint) | MSOP-8 (different SMD footprint) | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same |
| Program Memory | 1.5 KB Flash (1K x 12) | 1.5 KB Flash | 1.5 KB Flash | 0.75 KB Flash | 1.5 KB Flash | 0.75 KB OTP EPROM |
| RAM | 41 bytes | 41 bytes | 41 bytes | 25 bytes | 41 bytes | 25 bytes |
| Data EEPROM | 41 bytes | 41 bytes | 41 bytes | None | 41 bytes | 16 bytes |
| Maximum CPU Speed | 4 MHz (4 MIPS) | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Operating 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 | 2.5 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 +125 C (Extended) | -40 C to +125 C |
| Unit Price (qty-1, USD) | 1.30 | 1.45 | 1.35 | 1.20 | 1.40 | 1.10 (OTP EPROM, lower cost) |
Key Differentiators
- Highest Flash density in 8-pin SOIC PIC10/12 baseline family (vs PIC12F508-I/SN)
- Single lowest-cost 8-bit Flash MCU with both data EEPROM and 4 MHz internal oscillator (vs PIC12CE518-04E/SN)
- Industrial temperature range at lower cost than the extended-temperature variant (vs PIC12F509-E/SN)
Design Notes
For battery-powered designs, disable the watchdog timer (WDTE = 0b0 in CONFIG) to achieve sub-1 uA sleep currents on the PIC12F509-I/SN. Estimated: with watchdog on, sleep current is ~5-10 uA typical at 3 V; with watchdog off, it drops to <1 uA, extending a CR2032 (220 mAh) coin-cell life from years to over a decade in a duty-cycled sensor application. Always use the brown-out reset (BOREN = 1) to prevent undefined execution during battery brown-out, and select the lowest BOR voltage threshold (BORV = 1) for 2.0 V minimum operation.
Keep the ICSP pins (GP0/ICSPCLK and GP1/ICSPDAT) accessible on the production PCB by routing them to a 2x3 or 1x6 header strip, even if they are also used as GPIO in the application. The 0.1 inch pitch header is the Microchip recommended ICSP layout per the PICkit 5 user guide. Place a 100 nF decoupling capacitor within 5 mm of the VDD pin (pin 1) and a bulk capacitor (10 uF) at the supply entry point. The VSS pin (pin 8) should connect to a ground pour with at least one via nearby for thermal dissipation.
Do not use GP3 (pin 4) as a general-purpose output - it is input-only and doubles as the MCLR/reset input. If MCLR is enabled in CONFIG (MCLRE = 1), pin 4 must be pulled high to VDD through a 10 kohm resistor; leaving it floating will cause intermittent resets. Also note that the internal 4 MHz oscillator is calibrated at 5 V / 25 C; for UART bit-banging at 3.3 V, recalibrate the OSCCAL register or accept ±2-3% baud-rate error. The ICSP clock and data lines share GP0/GP1, so high-speed switching on those pins during programming may affect in-circuit debugging.
When the PIC12F509-I/SN drives long cables (sensor wires, RS-485-style differential signaling from a transceiver), series-terminate the output with 100 ohm resistors to dampen reflections, and add a TVS diode (e.g., PESD5V0L1BA) at the connector for ESD protection. The internal 4 MHz oscillator has limited immunity to fast supply transients; place a ferrite bead or 10 ohm resistor in series with VDD for noisy industrial environments, and bulk-decouple with 10 uF electrolytic in parallel with the 100 nF ceramic decoupling cap. For EMI-sensitive applications, route GP0/GP1 signals over an unbroken ground plane and avoid running them parallel to switching power traces.
Estimated: The PIC12F509-I/SN in 8-pin SOIC has a junction-to-ambient thermal resistance theta_JA of approximately 100 C/W. At maximum operating current of ~5 mA active at 5.5 V (worst case), power dissipation is ~28 mW, yielding a junction temperature rise of ~2.8 C above ambient - well within the 85 C industrial limit. No thermal management is required for any realistic 8-pin SOIC application. The PIC12F509's CMOS design is inherently low-power and self-heating is negligible compared to ambient temperature variation.
Compliance Information
RoHS and lead-free per Microchip product page (PIC12F509 family is lead-free and RoHS compliant). Not AEC-Q100 qualified; for automotive use, choose a -Q1 suffix variant or migrate to PIC16F15313. Halogen-free status not explicitly stated in the verified web data and is marked unknown. The alternative PIC12CE518-04E/SN is flagged 'Not Halogen Free' on GlobalSpec.
