PIC12C509A-04/SN - 8-Bit 4MHz OTP MCU 1.5KB | Microchip
MPN: PIC12C509A-04/SN β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.65 | $16.50 |
| 100 | $1.42 | $142.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $0.98 | $980.00 |
PIC12C509A-04/SN Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, memory, and peripheral interfaces into one IC. The PIC12C5xx family is one of the smallest 8-bit microcontrollers Microchip produces, packaging the full PIC architecture into an 8-pin footprint. It belongs to the broader category of embedded microcontrollers -> 8-bit microcontrollers -> CMOS RISC microcontrollers -> PIC microcontrollers -> semiconductors.
Key features of the PIC12C509A-04/SN include six general-purpose I/O lines, two timers, a Watchdog Timer (WDT) for reliable operation, a Power-on Reset (POR) circuit, and an internal 4MHz oscillator. The device operates across a 2.5V to 5.5V supply range (typical 3.3V/5V operation) and is rated for the commercial 0C to +70C temperature range (the -04 speed grade denotes 4MHz). OTP memory is factory-programmable and ideal for low-to-medium volume production runs.
The PIC12C509A uses a Harvard architecture with a 12-bit program word and an 8-bit data path, allowing predictable single-cycle instruction execution. Its compact register file contains 7 special function registers and 25 general purpose registers plus 16 addressable via banking. The 8-pin SOIC (SN) package supports surface-mount assembly on 1.27mm pitch pads.
Typical applications include automotive subsystems, industrial appliance control, consumer electronics entry-level products, sensor interface front-ends, and low-cost timing/replacement logic. Six I/O pins are sufficient for simple state machines, LED drivers, and signal conditioning. Industrial designers often use the PIC12C509A for cost-sensitive and space-constrained glue logic replacement.
When designing, note that the OTP memory requires a device programmer (e.g., PICkit) and cannot be re-programmed in-circuit. For prototype or field-updatable designs, consider the Flash-based PIC12F509 alternative, which is pin-compatible with most PIC12C509A designs. The 8-SOIC package requires 1.27mm pitch land pattern and a clean analog supply if used with ADC.
This page synthesizes distributor pricing, drop-in PIC12C509A family alternatives, and practical design notes not consolidated on the manufacturer datasheet.
Drop-in alternatives for PIC12C509A-04/SN β 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 PIC12C509A-04/SN (same form factor and footprint) β differing in Package, Timers, Core Architecture, Watchdog Timer, I/O Pins.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC12C509A-04I/SN
β Drop-Inβ In Stock
$0.92 / Unit
View Datasheet βPIC12C509A-04E/SN
β Drop-Inπ Reference alternative (not in catalog)
PIC12C509A-04/SM
β Drop-Inβ In Stock
$0.99 / Unit
View Datasheet βPIC12F509-I/SN
β Drop-Inπ Reference alternative (not in catalog)
PIC12LC509A-04E/SN
β Drop-Inπ Reference alternative (not in catalog)
PIC12C509A-04/SN Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory | 1.5KB (1K x 12) OTP |
| Data RAM | 41 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle Time | 1 us |
| Number of Instructions | 33 single-word |
| Operating Voltage | 2.5 V to 5.5 V (3.3V/5V typ.) |
| I/O Pins | 6 |
| Timers | 2 |
| Watchdog Timer | Yes |
| Power-on Reset | Yes |
| Package | 8-SOIC (SN) |
| Pin Pitch | 1.27 mm |
| Mounting Type | Surface Mount |
| Temperature Range | 0C to +70C (commercial) |
| RoHS Status | Compliant |
PIC12C509A-04/SN Pin Configuration
| Pin 1 | GP5/OSC1/CLKIN β General-purpose I/O / oscillator input / external clock input |
| Pin 2 | GP4/OSC2/CLKOUT β General-purpose I/O / oscillator output / clock output (1/4 of Fosc) |
| Pin 3 | GP3/MCLR/VPP β General-purpose I/O / Master Clear reset (active low) / programming voltage |
| Pin 4 | VSS β Ground reference |
| Pin 5 | GP0 β General-purpose I/O / ICSP data |
| Pin 6 | GP1 β General-purpose I/O / ICSP clock |
| Pin 7 | GP2/T0CKI β General-purpose I/O / Timer 0 clock input |
| Pin 8 | VDD β Positive supply (2.5V-5.5V) |
Typical Applications
PIC12C509A-04/SN is suitable for 6 applications: Automotive Body Electronics, Industrial Appliance Control, Consumer Entry-Level Products, Sensor Interface Front-End, Glue Logic Replacement, LED Driver Controller.
Automotive Body Electronics
The PIC12C509A-04/SN fits automotive body electronics such as lighting controllers, simple sensor interfaces, and accessory timing modules. Its 6 GPIO and two timers are sufficient for body-control tasks like wiper interval timing, mirror-position memory, and LED dimming, while the 4MHz core delivers 4 MIPS - enough to handle 10-20ms polling loops with margin. The 8-SOIC package measures only 3.90mm wide, fitting the cramped PCB outlines typical behind dashboards. The -04I/SN industrial-grade variant extends temperature coverage to -40C to +85C, qualifying the device for cabin and under-hood periphery. Compared to discrete 555-timer logic, the PIC12C509A replaces 2-4 ICs and one PCB area at lower BOM cost, while consuming <2 mA active and <1 uA sleep current.
Recommended
Industrial Appliance Control
The PIC12C509A-04/SN is widely deployed in industrial appliance control, including small pump drivers, solenoid multiplexers, and HVAC damper actuators. Its built-in Power-on Reset and Watchdog Timer provide the field reliability demanded by appliance safety standards (e.g., IEC 60335), while OTP memory prevents accidental firmware corruption from voltage transients on the mains rail. The 6 I/O pins can directly drive triacs or optocouplers via 25 mA source/sink, eliminating level-shifters. The Harvard RISC core deterministically executes 33 instructions in 1us, simplifying timing-critical tasks like zero-crossing detection for TRIAC dimming. Compared to a CMOS 4000-series logic replacement, the PIC12C509A reduces component count from 4-6 gates to a single 8-pin IC and adds reprogrammable logic at near-discrete cost.
Recommended
Consumer Entry-Level Products
The PIC12C509A-04/SN targets cost-sensitive consumer products such as remote-control key fobs, simple toys, novelty LED gadgets, and kitchen timers. Its $0.98 unit price at 1K quantity (as of 2026-09-14) keeps BOM cost low enough for sub-$5 retail items, while the 8-SOIC footprint occupies less than 25 mm squared of board area. OTP memory prevents casual firmware extraction in security-sensitive applications like garage-door openers. Six I/O lines can matrix-scan a 3x3 keypad, drive a 7-segment LED display via current-limit resistors, and read two analog comparators through the digital I/O for thermistor interfaces. The 2.5V-5.5V range lets designers use a single CR2032 coin cell or USB-derived 5V supply without level translation.
Recommended
Sensor Interface Front-End
The PIC12C509A-04/SN excels as a low-cost sensor interface front-end for thermistor, photocell, and switch-debounce applications. Its two timers can be cascaded to generate long-period sample intervals (up to 16 seconds with a 32.768 kHz external timebase) while the WDT guards against firmware lockup in unattended sensor nodes. Six GPIO can implement a polled multi-sensor scan, with one pin dedicated to interrupt-wake from sleep for event-driven sensing. The 4MHz instruction rate is sufficient to debounce mechanical switches in software, eliminating RC filter components. For battery-powered wireless sensor nodes, the PIC12C509A's <1 uA sleep current extends coin-cell life to multi-year operation when paired with a sub-1 GHz transmitter.
Recommended
Glue Logic Replacement
The PIC12C509A-04/SN is increasingly used to replace discrete 7400-series glue logic in modern designs, combining 2-4 SSI gates into a single 8-pin IC. Designers implement state machines, pulse generators, and watchdog supervisors that would otherwise require 2-4 separate packages, reducing PCB area and assembly cost. The 4MHz core can synthesize frequencies from 1 Hz to 2 MHz via timer interrupts, replacing NE555 timer ICs with a more flexible, reprogrammable alternative. The OTP memory ensures the logic function cannot be reverse-engineered via firmware readback, providing modest IP protection. The 8-SOIC footprint is footprint-compatible with common 74HC00-family SOIC-8 parts, enabling drop-in PCB re-use with a firmware-only redesign.
Recommended
LED Driver Controller
The PIC12C509A-04/SN drives LED arrays in signage, indicator panels, and decorative lighting through PWM generated by its on-chip timers. The 6 GPIO can independently drive 6 high-brightness LEDs at 25 mA each, or 12 LEDs in a Charlieplex matrix using the same pin count. Software-controlled PWM at 4 MIPS supports >1000:1 dimming ratios at 1 kHz refresh rates, eliminating visible flicker in camera-monitored installations. The 2.5V-5.5V operating range accommodates both 3.3V logic-level LEDs and 5V high-current strings. The OTP memory stores fade patterns, blink sequences, and color-mixing profiles as a fixed state machine, freeing an external host processor from low-level timing tasks. Per FindMyChip cross-reference data, this is one of the most common PIC12C509A application patterns.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509A-04/SN β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509A-04I/SN | PIC12C509A-04E/SN | PIC12F509-I/SN | PIC12C509A-04/SM | PIC12LC509A-04E/SN |
|---|---|---|---|---|---|---|
| Package | 8-SOIC (SN, 3.90mm) | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIJ (SM, 5.28mm) - different | 8-SOIC (SN) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 1.5KB OTP | 1.5KB OTP | 1.5KB OTP | 1.5KB Flash | 1.5KB OTP | 1.5KB OTP |
| Data RAM | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes |
| Max Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Operating Voltage | 2.5V-5.5V | 2.5V-5.5V | 2.5V-5.5V | 2.0V-5.5V | 2.5V-5.5V | 2.5V-5.5V |
| Temperature Range | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +125C (extended) | -40C to +85C (industrial) | 0C to +70C (commercial) | -40C to +125C (extended) |
| Memory Type | OTP (one-time programmable) | OTP | OTP | Flash (reprogrammable) | OTP | OTP |
Key Differentiators
- Commercial-temperature 8-SOIC pricing in a mature PIC family (vs PIC12C509A-04I/SN)
- OTP memory prevents firmware extraction in security applications (vs PIC12F509-I/SN)
- 32x4 register file with hardware banking for compact code (vs ATtiny13 (cross-vendor reference))
Design Notes
The PIC12C509A-04/SN operates from 2.5V to 5.5V with typical active current under 2 mA at 4MHz and sleep current below 1 uA (per DS40139E). For battery designs, place a 100 nF decoupling capacitor within 5 mm of the VDD pin to suppress digital switching noise. If using a switching regulator for VDD, add a 10 uF bulk capacitor in parallel. The internal POR circuit handles power-on sequencing, so no external reset IC is required for most applications. Estimated: at 5V VDD and 4MHz active mode, total current is approximately 1.7 mA per the PIC12C5xx datasheet typical characteristics.
The 8-SOIC (SN) package requires a 1.27 mm pitch land pattern with pad dimensions per IPC-7351 nominal. Keep the trace from VDD pin 8 to the decoupling cap shorter than 5 mm to minimize parasitic inductance. For noisy environments (e.g., near relay coils or motor drivers), route the MCLR pull-up directly to VDD and add a 100 nF capacitor from MCLR to VSS to filter transient resets. The ICSP programming pins (GP0/GP1) can be left connected to the application circuit during programming if the load does not exceed 25 mA source/sink, but adding 4.7 kohm series resistors prevents programming conflicts.
Do not assume OTP memory can be re-programmed - it is one-time-programmable only. The PIC12C509A-04/SN does not support in-circuit serial programming (ICSP) because the OTP cell cannot be erased; use the PIC12F509-I/SN for development. The MCLR pin (pin 3) is shared with GP3, so leaving MCLR floating or tying it to VDD without a pull-up can cause spurious resets from electrical noise. The internal 4MHz oscillator has +/-2% tolerance across temperature and voltage, so external timing applications (e.g., UART baud generation above 9600 baud) may require a crystal or external resonator. Watchdog Timer must be cleared at least every 18 ms (typical WDT period at 4MHz) to prevent unwanted reset.
Compliance Information
RoHS and REACH compliance per Microchip product declaration. Not AEC-Q100 qualified - use PIC16/18 family for AEC-Q100 automotive applications. Lead-free finish is standard on the SN package.
