PIC12C509AT-04I/SM - 8-bit 4MHz 1.5KB OTP MCU SOIJ-8 | Microchip
MPN: PIC12C509AT-04I/SM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.65 | $2.65 |
| 10 | $2.3 | $23.00 |
| 100 | $1.85 | $185.00 |
| 500 | $1.62 | $810.00 |
| 1,000 | $1.4 | $1,400.00 |
PIC12C509AT-04I/SM Overview
An 8-bit microcontroller (MCU) is a small computer-on-a-chip containing a processor core, program memory (ROM/Flash/OTP), data RAM, and a set of peripheral interfaces such as timers, I/O ports and analog channels. The 8-bit PIC12C5xx architecture from Microchip implements a RISC instruction set of only 33 single-word instructions and executes them in 1 µs per instruction cycle at 4 MHz, making it easy to program in assembly or C while leaving enough headroom for tight control loops.
Key features include a built-in 8-bit timer/counter (TMR0) with an 8-bit programmable prescaler, power-on reset (POR), device reset timer (DRT), a watchdog timer (WDT) with its own on-chip RC oscillator for reliable operation, and programmable code protection. The 'A' revision of the PIC12C509 improves on the original PIC12C509 baseline with enhanced oscillator options and a wider operating range, while the 'T' suffix denotes tape-and-reel packaging for high-volume assembly.
The PIC12C509AT-04I/SM operates from 2.5 V to 5.5 V and supports an industrial temperature range of -40 °C to +85 °C. With 6 general-purpose digital I/O pins multiplexed onto an 8-pin footprint, the device trades analog peripherals for an exceptionally small bill of materials, suiting cost-sensitive applications such as appliance controllers, sensor signal conditioning and logic replacement. The OTP program memory allows one-time programming in production, which lowers unit cost versus flash-based devices.
Typical applications include automotive subsystems, white-goods and small-appliance controls, industrial sensors and actuators, consumer entry-level products, and remote-control transmitters. The PIC12C5xx family is widely used as a 'smart glue' logic replacement in designs that need a small amount of decision-making but not the overhead of a larger MCU.
When designing with this part, note that OTP memory cannot be re-programmed in the field; use PIC12F or PIC16F equivalents if firmware updates are required. The 8-pin SOIJ package shares a common footprint with PIC10F, PIC12C5xx, and PIC12C6xx devices, enabling migration paths within the PIC10/12/16 ecosystem.
This page synthesizes distributor pricing, drop-in alternatives and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC12C509AT-04I/SM — 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 PIC12C509AT-04I/SM (same form factor and footprint) — differing in Program Memory Size, Package, Timers, Core Architecture, Instruction Execution Time.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12C509A-04I/SM
✅ Drop-In✓ In Stock
$0.93 / Unit
View Datasheet →PIC12C509A-04/SM
✅ Drop-In✓ In Stock
$0.99 / Unit
View Datasheet →PIC12C509A-04I/SN
✅ Drop-In✓ In Stock
$0.92 / Unit
View Datasheet →PIC12C509A-04E/SM
✅ Drop-In✓ In Stock
$1.55 / Unit
View Datasheet →PIC12LC509A-04I/SM
✅ Drop-In✓ In Stock
$0.71 / Unit
View Datasheet →PIC12C508A-04I/SM
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC12C509AT-04I/SM Maximum Ratings & Electrical Characteristics
| Core | PIC 8-bit RISC |
| Core Size | 8-bit |
| Instruction Set | 33 single-word instructions |
| Instruction Cycle | 1 µs at 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM Size | 41 bytes |
| EEPROM | 0 bytes (none) |
| Maximum CPU Frequency | 4 MHz |
| Supply Voltage | 2.5 V to 5.5 V |
| I/O Pins | 6 |
| Timers | 1 x 8-bit TMR0 with 8-bit programmable prescaler |
| Watchdog Timer | Yes, with dedicated on-chip RC oscillator |
| Power-On Reset | Yes (POR + DRT) |
| Code Protection | Programmable |
| Operating Temperature | -40 °C to +85 °C (Industrial, 'I' suffix) |
| Package | 8-SOIJ (SOIJ-8, 5.23 mm body, 208 mil) |
| Mounting Type | Surface Mount |
PIC12C509AT-04I/SM Pin Configuration
| Pin 1 | GP2/T0CKI — GPIO GP2 / Timer0 clock input |
| Pin 2 | GP1 — GPIO GP1 |
| Pin 3 | GP0 — GPIO GP0 |
| Pin 4 | VSS — Ground reference |
| Pin 5 | GP3/MCLR/VPP — GPIO GP3 / Master Clear reset / Programming voltage |
| Pin 6 | GP4/OSC2/CLKOUT — GPIO GP4 / Oscillator crystal output / Clock out |
| Pin 7 | GP5/OSC1/CLKIN — GPIO GP5 / Oscillator crystal input / External clock in |
| Pin 8 | VDD — Positive supply voltage (2.5 V to 5.5 V) |
Typical Applications
PIC12C509AT-04I/SM is suitable for 6 applications: White Goods and Small Appliance Controllers, Automotive Body and Sensor Modules, Consumer Remote Control Transmitters, Industrial Sensor Signal Conditioning, Logic Replacement and Glue Logic, Battery-Powered IoT Edge Nodes.
White Goods and Small Appliance Controllers
The PIC12C509AT-04I/SM is a strong fit for low-cost appliance controllers such as toaster ovens, coffee makers, irons and small fan controllers. Its 8-pin SOIJ footprint and 6 GPIOs can directly drive triac outputs, read keypad or rotary encoder inputs and time heating cycles using the built-in TMR0 with 8-bit prescaler. The 1.5 KB OTP program memory is ample for fixed-state-machine appliance logic, while the 2.5 V–5.5 V supply range allows direct connection to rectified mains-derived rails after a small linear regulator. The OTP architecture also keeps per-unit cost at the absolute minimum, which matters in high-volume consumer appliances.
Recommended
Automotive Body and Sensor Modules
The PIC12C509AT-04I/SM can serve as a smart logic-replacement controller in automotive subsystems such as seat-occupancy sensors, simple lighting drivers and rain-sensor interfaces. Its industrial -40 °C to +85 °C temperature rating suits cabin and under-hood-adjacent locations, while the 41 bytes of RAM and 1.5 KB OTP are sufficient for fixed-function sensor signal conditioning algorithms. The 8-pin SOIJ package drops directly onto small sensor PCBs that previously used discrete 555 timer circuits, replacing analog timing with software-reprogrammable behavior at production time.
Recommended
Consumer Remote Control Transmitters
For IR/RF remote controls and simple wireless key fobs, the PIC12C509AT-04I/SM offers just enough GPIO and code space to implement fixed-button-to-code mapping with carrier modulation. The TMR0 prescaler can produce accurate 38 kHz carrier timing for IR transmission, while sleep modes between button presses extend battery life on 2-cell alkaline or coin-cell supplies. Its tiny 8-SOIJ footprint fits inside the slim enclosures of handheld remotes, and the OTP architecture prevents firmware reverse-engineering better than flash-based MCUs at similar cost.
Recommended
Industrial Sensor Signal Conditioning
In industrial sensor conditioning modules, the PIC12C509AT-04I/SM can perform linearization, scaling and threshold detection on simple analog sensors by leveraging its GPIO with external op-amp front-ends and timer-based pulse measurement. The wide 2.5 V–5.5 V supply accommodates 24 V industrial bus rails after a front-end LDO, while the -40 °C to +85 °C industrial temperature grade ensures operation in factory-floor cabinets. Compared to discrete logic ICs, this 8-bit PIC adds programmability for sensor-specific calibration curves without increasing BOM cost significantly.
Recommended
Logic Replacement and Glue Logic
The PIC12C509AT-04I/SM frequently replaces discrete 74-series logic gates and 555 timer circuits when a design needs a small amount of decision-making, sequencing or pulse-width logic that cannot be expressed in fixed gates. The 6 GPIOs can implement state machines, debounced inputs, or PWM-like outputs under firmware control, reducing PCB area and component count. The OTP architecture means production cost is essentially the same as discrete logic once the volume threshold is met, and the device eliminates the need for analog timer component selection and drift.
Recommended
Battery-Powered IoT Edge Nodes
The PIC12C509AT-04I/SM suits very low-power edge-node devices such as battery-powered temperature loggers, pushbutton event counters and simple alarm sensors where the device spends most of its life in sleep and wakes only on a GPIO interrupt. Operating from 2.5 V–5.5 V, it can run directly from a 3 V coin cell or 2-cell alkaline pack without a regulator. The 4 MHz CPU clock executes the wake-up handler quickly enough to return to sleep, maximizing battery life, while the 1.5 KB OTP code space holds fixed sensor processing and reporting logic.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509AT-04I/SM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509A-04I/SM | PIC12C509A-04/SM | PIC12C509A-04I/SN | PIC12C509A-04E/SM | PIC12LC509A-04I/SM | PIC12C508A-04I/SM |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-SOIJ | 8-SOIJ - same | 8-SOIJ - same | SOIC-8 - same family, smaller body | 8-SOIJ - same | 8-SOIJ - same | 8-SOIJ - same |
| Program Memory | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 0.75 KB OTP |
| RAM | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 25 bytes |
| Maximum CPU Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Supply Voltage Range | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 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 | 0 °C to +70 °C (Commercial) | -40 °C to +85 °C | -40 °C to +125 °C (Extended) | -40 °C to +85 °C | -40 °C to +85 °C |
| I/O Pins | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| Watchdog Timer | Yes (with own RC oscillator) | Yes | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Largest OTP program memory in the SOIJ-8 PIC12C family (vs PIC12C508A-04I/SM)
- Industrial -40 °C to +85 °C temperature grade (vs PIC12C509A-04/SM)
- Same SOIJ-8 mechanical outline as legacy PIC12C509 (vs PIC12C509A-04I/SN)
Design Notes
Decouple VDD (pin 8) with a 100 nF ceramic capacitor placed within 5 mm of the supply pin and a bulk 10 µF tantalum or aluminum capacitor on the same rail. The PIC12C509A device family draws brief current spikes during internal EPROM programming; insufficient decoupling can cause VDD dips that corrupt code during production programming. Avoid routing high-current AC traces near the VDD pin to minimize injected noise on the supply rail.
Keep the crystal or resonator traces to GP4/OSC2 and GP5/OSC1 short and symmetric, with a ground guard ring on the PCB to reduce EMI pickup. Place load capacitors (typically 15–33 pF for a 4 MHz crystal) as close to the oscillator pins as possible. If using an external CMOS clock source, drive only GP5/OSC1 and leave GP4/OSC2 unconnected or configured as a GPIO to prevent contention.
OTP program memory cannot be re-programmed: the production firmware image must be 100% verified before programming, including all calibration constants, since field updates are impossible without a hardware replacement. Always reserve the MCLR/VPP pin (GP3) for in-circuit serial programming (ICSP) access on the PCB, even in production designs, to enable factory rework. For designs that need firmware updates in the field, choose a flash-based alternative such as PIC12F629 or PIC12F675 in the same SOIC-8 footprint.
At 4 MHz and 5 V supply the PIC12C509AT-04I/SM typically draws less than 2 mA active and a few µA in sleep, so no heatsink or thermal copper pour is required. However, industrial-temperature designs at -40 °C should verify oscillator start-up behavior at cold temperatures; some low-cost ceramic resonators may not start reliably below -20 °C and may require a 4 MHz crystal instead.
Compliance Information
RoHS and REACH compliance confirmed via Microchip product page. Not AEC-Q100 qualified for automotive safety-critical applications; for AEC-Q100 grade, select PIC12C509A-I/SN automotive variant. Halogen-free status not explicitly stated in retrieved datasheets.
