PIC12F509T-I/MS - 8-bit MCU 1.5KB Flash 6 I/O MSOP-8 | Microchip
MPN: PIC12F509T-I/MS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.06 | $1.06 |
| 10 | $0.92 | $9.20 |
| 100 | $0.78 | $78.00 |
| 500 | $0.69 | $345.00 |
| 1,000 | $0.61 | $610.00 |
| 2,500 | $0.54 | $1,350.00 |
PIC12F509T-I/MS Overview
A baseline PIC12 microcontroller (MCU) is a small 8-bit flash-programmable controller built on Microchip's RISC architecture. MCUs sit in the device hierarchy below microprocessors; the PIC12 family is the entry-level 8-bit line optimized for cost-sensitive, low-pin-count embedded applications, while the broader PIC® family extends into 16-bit and DSC parts. The PIC12F509 specifically is a flash-based successor to the original 12C508/509 OTP family, giving users reprogrammable code memory in the same 8-pin footprint.
Key features of the PIC12F509T-I/MS include a 4 MHz internal oscillator with 1% accuracy (factory calibrated), a 41-byte general-purpose RAM, an 8-level hardware stack, a watchdog timer with on-chip low-power oscillator, and a precision 4 MHz LFINTOSC. The device integrates brown-out reset, power-on reset, and an in-circuit serial programming (ICSP) interface, allowing firmware updates without removing the part from the board. The "T" suffix denotes Tape & Reel packaging for high-volume assembly.
Architecturally, the PIC12F509 uses a 12-bit instruction word with single-cycle execution except for branches, delivering typical 2:1 code compression over comparable 8-bit controllers. Its Harvard architecture separates program and data paths, and the 33 single-word instructions simplify firmware development in MPLAB® X IDE and the MPASM/XC8 toolchain.
Typical applications include low-cost consumer appliances, LED lighting controllers, battery chargers, sensor interfaces, and simple standby controllers in industrial equipment. With only six usable I/O, the part fits tightly-constrained boards where a full 14- or 20-pin MCU would be overkill.
When designing with this part, ensure the GP3 pin is configured carefully because it is the only open-drain input shared with the MCLR/VPP function. Place a 100 nF decoupling capacitor adjacent to VDD, and connect VSS directly to a low-impedance ground plane to minimize EMI on the internal oscillator.
This page synthesizes Microchip datasheet parameters, distributor pricing tiers, drop-in alternatives drawn from the PIC12 baseline family, and practical design notes not aggregated elsewhere on XAIPART.
Drop-in alternatives for PIC12F509T-I/MS — 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 PIC12F509T-I/MS (same form factor and footprint) — differing in Package, Internal Oscillator, Timers, Watchdog Timer, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12F509-I/MS
✅ Drop-In✓ In Stock
$0.51 / Unit
View Datasheet →PIC12F509T-I/MC
✅ Drop-In✓ In Stock
$0.28 / Unit
View Datasheet →PIC12F509-E/MS
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →PIC12F509-E/MC
✅ Drop-In✓ In Stock
$0.5 / Unit
View Datasheet →PIC12F508T-I/MC
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F508-I/MC
✅ Drop-In✓ In Stock
$0.47 / Unit
View Datasheet →PIC12F509T-I/MS Maximum Ratings & Electrical Characteristics
| Product Family | PIC® 12F (baseline, 8-bit) |
| Core Architecture | PIC RISC, 8-bit, 12-bit instruction word |
| Program Memory (Flash) | 1.5 KB (1K x 12) |
| RAM | 41 bytes |
| EEPROM (on-chip data) | None |
| I/O Pins | 6 (5 bidirectional GPIO + 1 input-only GP3/MCLR) |
| CPU Speed | 4 MHz (DC to 4 MHz instruction rate) |
| Instruction Set | 33 instructions, single-cycle except branches |
| Hardware Stack | 8 levels |
| Operating Voltage (VDD) | 2.0 V to 5.5 V |
| Internal Oscillator | 4 MHz LFINTOSC, factory calibrated ±1% |
| Watchdog Timer | Yes, with dedicated on-chip low-power oscillator |
| Brown-Out Reset / POR | Yes |
| In-Circuit Serial Programming (ICSP) | Yes |
| Package | 8-pin MSOP |
| Operating Temperature | -40°C to +85°C (Industrial, "I") |
| Mounting Type | Surface Mount |
| MSL Level | MSL1 (per Microchip package profile) |
| RoHS Status | Compliant |
| Lead-Free | Yes (Matte Tin finish) |
PIC12F509T-I/MS Pin Configuration
| Pin 1 | VDD — Positive supply voltage (2.0 V to 5.5 V) |
| Pin 2 | GP5/T1CKI/OSC1/CLKIN — Bidirectional I/O / Timer1 clock input / Crystal oscillator input / External clock input |
| Pin 3 | GP4/AN3/T1G/OSC2/CLKOUT — Bidirectional I/O / analog input / Timer1 gate / Crystal oscillator output / Clock out (FOSC/4) |
| Pin 4 | GP3/MCLR/VPP — Input-only / Master Clear (reset) / Programming voltage input |
| Pin 5 | GP2/T0CKI/INT/COUT/FOSC4 — Bidirectional I/O / Timer0 clock input / External interrupt / Comparator output / FOSC/4 output |
| Pin 6 | GP1/CIN-/ICSPCLK — Bidirectional I/O / Comparator inverting input / ICSP clock |
| Pin 7 | GP0/CIN+/ICSPDAT — Bidirectional I/O / Comparator non-inverting input / ICSP data |
| Pin 8 | VSS — Ground reference |
Typical Applications
PIC12F509T-I/MS is suitable for 7 applications: LED Lighting Controller, Battery Charger Controller, Industrial Sensor Interface, Consumer Appliance Control, IoT Sensor Node (Simple), Standby / Auxiliary Power Controller, Automotive Accessory Module.
LED Lighting Controller
The PIC12F509T-I/MS fits LED lighting controllers where 6 I/O is sufficient for one or two PWM channels plus a few status LEDs. Its 4 MHz LFINTOSC with ±1% factory accuracy provides flicker-stable PWM at 1 kHz without external timing components, and the 2.0 V to 5.5 V supply range allows direct connection to a 3.3 V or 5 V LED driver rail. The 1.5 KB flash is enough for color-mixing logic in RGB accent lights or simple dimming curves. Designers place 100 nF decoupling adjacent to VDD and route GP2 as the PWM output.
Recommended
Battery Charger Controller
The PIC12F509T-I/MS works as a simple battery charger controller where charge-current sensing and timer logic only need 6 I/O. Its 2.0 V minimum supply supports single-cell Li-ion or NiMH packs directly, while the internal 4 MHz oscillator provides reliable timing for CC/CV state transitions. Brown-out reset and watchdog timer protect against low-voltage lockup during deep discharge. A 1.5 KB flash holds the state machine plus temperature-compensation look-up tables. The exposed GP3/MCLR doubles as a wake-up source from sleep mode.
Recommended
Industrial Sensor Interface
The PIC12F509T-I/MS handles industrial sensor signal conditioning where the MCU must debounce switches, count pulses, and drive a logic-level output. With 6 I/O, it accepts two digital sensor inputs (GP0, GP1) plus a frequency input (GP5/T1CKI), and drives three outputs for indicator LEDs or relay drivers via external transistors. The 41-byte RAM handles running pulse counts; 1.5 KB flash stores calibration constants. Operating from -40°C to +85°C industrial range, the part suits factory-floor modules with limited board space and EMI-rich environments.
Recommended
Consumer Appliance Control
The PIC12F509T-I/MS fits small consumer appliances like coffee makers, blenders, and humidifiers that need button scanning, timer logic, and relay/SSR drive. Six I/O accommodate three buttons, a buzzer, and a triac gate drive, while the 1.5 KB flash holds menu logic and timing routines. Brown-out reset protects against mains brownouts common with inductive loads. The MSOP-8 footprint simplifies PCB layout in space-constrained housings, and the 2.0 V to 5.5 V range allows direct 3.3 V logic compatibility.
Recommended
IoT Sensor Node (Simple)
The PIC12F509T-I/MS serves low-bandwidth IoT nodes such as temperature beacons or door/window contact sensors where the MCU reads one digital input, applies debounce logic, and drives a low-power radio enable line. Six I/O is sufficient for I²C-style bit-banging to a sensor plus a wake-up GPIO. 1.5 KB flash holds the radio enable pulse pattern and basic security handshakes; 41 bytes RAM handles running averages. Power consumption in Sleep mode is microamp-range when the watchdog is disabled, supporting multi-year coin-cell operation.
Recommended
Standby / Auxiliary Power Controller
The PIC12F509T-I/MS acts as a standby microcontroller that wakes a main system on a button press or external event. Its low-power Sleep mode draws single-digit microamps, and the watchdog timer or external interrupt on GP3/MCLR wakes the part within microseconds. The 1.5 KB flash handles power-sequencing state machines, while 41 bytes RAM tracks wake events. The 2.0 V to 5.5 V supply range lets it run directly from a system standby rail. Designers pair it with a main MCU for smart-home hubs or set-top boxes.
Recommended
Automotive Accessory Module
The PIC12F509T-I/MS fits cost-sensitive automotive accessories such as ambient lighting strips, simple alarm indicators, and aftermarket convenience modules. Six I/O drive RGB LED channels or relay outputs; the 4 MHz LFINTOSC provides stable timing for blinking patterns. While the part is rated -40°C to +85°C, designs targeting engine-bay mounting should use the extended-temperature PIC12F509-E/MS variant (which retains the same 8-pin MSOP footprint). Designers should add external ESD protection on GP3/MCLR since automotive environments are ESD-rich.
Recommended
Recommended Products Summary
Engineering reference data for PIC12F509T-I/MS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12F509-I/MS | PIC12F509T-I/MC | PIC12F509-E/MS | PIC12F508T-I/MC | PIC12F508-I/MC |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-pin MSOP | 8-pin MSOP | 8-pin MSOP | 8-pin MSOP | 8-pin MSOP | 8-pin MSOP |
| Program Memory (Flash) | 1.5 KB | 1.5 KB | 1.5 KB | 1.5 KB | 0.75 KB | 0.75 KB |
| RAM | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 25 bytes | 25 bytes |
| I/O Pins | 6 | 6 | 6 | 6 | 6 | 6 |
| Max CPU Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Operating Temperature | -40°C to +85°C (I) | -40°C to +85°C | -40°C to +85°C | -40°C to +125°C (E) | -40°C to +85°C | -40°C to +85°C |
| Packaging Format | Tape & Reel (T) | Tube | Tape & Reel | Tube | Tape & Reel | Tube |
| RoHS / Lead-Free | RoHS Compliant / Lead-Free | RoHS Compliant / Lead-Free | RoHS Compliant / Lead-Free | RoHS Compliant / Lead-Free | RoHS Compliant / Lead-Free | RoHS Compliant / Lead-Free |
Key Differentiators
- Tape-and-Reel packaging for high-volume SMT assembly (vs PIC12F509-I/MS)
- Industrial temperature grade -40°C to +85°C standard (vs PIC12F509-E/MS (extended temperature))
- Same die as PIC12F509T-I/MC in DFN-8 (vs PIC12F509T-I/MC)
- 1.5 KB flash versus 0.75 KB on the PIC12F508 family (vs PIC12F508T-I/MC)
- Compact MSOP-8 footprint with RISC 12-bit core (vs PIC12F509-I/P (PDIP-8))
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as physically possible to the VDD pin (pin 1) with a short, wide trace to the VSS pin (pin 8). For battery applications above 50 mA peak load, add a 10 µF bulk capacitor adjacent to the MCU. The internal 4 MHz LFINTOSC starts in roughly 4 µs; allow a 1 ms power-on-reset delay before executing code. Brown-out reset voltage is internally set and not user-adjustable on the PIC12F509.
The MSOP-8 land pattern requires thermal pad isolation - route VSS on a dedicated ground pour directly under pin 8 to minimize EMI coupling into the internal oscillator. Avoid routing noisy switching traces under the package or within 2 mm of the LFINTOSC pins (GP4/OSC2, GP5/OSC1) when used in external clock mode. Keep the MCLR/VPP trace short and shielded to prevent spurious resets in noisy industrial environments.
GP3 is the only input-only pin shared with the MCLR/VPP function; configure CONFIG< MCLRE > carefully because disabling MCLR repurposes GP3 as a digital input. When using ICSP, ensure no low-impedance load is connected to GP0 or GP1 (the ICSPDAT/ICSPCLK pins) during programming, or the programmer will fail to communicate. Do not exceed 5.5 V on any I/O pin - the absolute maximum is VDD + 0.3 V. The watchdog timer uses a separate internal low-power oscillator (~32 kHz typical) that is not synchronized to the main instruction clock, so WDT timeouts vary by approximately ±20%.
At 4 MHz and 5 V, the PIC12F509T-I/MS consumes roughly 2 mA active current. Power dissipation in the MSOP-8 package is well below 100 mW, so thermal management is not a concern. However, in enclosed housings with no airflow, the ambient temperature can rise above +70°C; in such cases, the extended-temperature PIC12F509-E/MS variant (rated to +125°C) provides additional margin without changing the footprint or BOM cost significantly.
When designing with the comparator peripheral on GP0/CIN+ and GP1/CIN-, keep analog traces short and surrounded by a ground guard ring. The internal comparator can source/sink only a few microamps; for higher drive, buffer with an external op-amp. For PWM generation, software bit-banging on GP2 or GP4 produces a stable signal because the instruction-cycle timing is locked to the LFINTOSC; avoid using the comparator output pin for PWM because the comparator response time is non-deterministic.
Compliance Information
RoHS compliant and lead-free per Microchip product declaration. The PIC12F509T-I/MS is not AEC-Q100 qualified; for automotive designs requiring formal qualification, evaluate Microchip's PIC16F or dsPIC automotive lines. REACH SVHC declaration available from Microchip's environmental compliance page.
