PIC12C509A-04/SM - 8-bit 4MHz OTP MCU 1.5KB | Microchip
MPN: PIC12C509A-04/SM β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.66 | $16.60 |
| 100 | $1.42 | $142.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $0.99 | $990.00 |
PIC12C509A-04/SM Overview
A PIC microcontroller (Programmable Interrupt Controller) is a family of 8-bit RISC microcontrollers built around a Harvard architecture with separate program and data buses. The PIC12C family represents the lowest pin-count segment of the PIC family (8 pins) and is widely used as a 'glue logic' replacement, intelligent sensor interface, or simple state controller where space and cost dominate the design budget. The PIC12C509A uses CMOS process technology and is fully static, allowing the clock to be stopped without losing register state.
Key features of the PIC12C509A-04/SM include a watchdog timer with on-chip RC oscillator for reliable operation, power-on reset, power-saving SLEEP mode, and a precision 4 MHz internal RC oscillator option. The device operates over the standard commercial 0C to +70C range (no /I industrial or /E extended temp suffix on this MPN). With 1024 words of OTP program memory and 41 bytes of RAM, it targets small, low-cost, code-volume applications such as sensor signal conditioning, LED blink controllers, and appliance user-interface logic.
Architecturally, the PIC12C509A uses a 12-bit instruction word and an 8-bit data path, with two I/O ports (GPIO, GP1-GP5) that share pins with the device's internal functions such as the T0CKI timer input, the MCLR reset, and the GP3 general-purpose pin. The oscillator can be selected from an external RC, external crystal/ceramic resonator, or the internal 4 MHz RC, simplifying BOM cost. Code protection is supported via a configuration bit to lock OTP contents.
Typical applications for the PIC12C509A-04/SM include simple sensor interfaces (e.g., thermistor or thermopile readout), battery-powered LED drivers, low-end appliance controls (rice cookers, fans, coffee makers), and consumer accessories (toys, IR remote transmitters, personal care devices). It is commonly paired with an EEPROM such as 24LC02 for non-volatile parameter storage, and a low-cost op-amp for analog signal conditioning.
When designing with this device, select a programmer/debugger compatible with OTP PIC12C parts (e.g., PICSTART Plus, MPLAB ICD 2/3, or PICkit 3). Because OTP memory cannot be erased, choose the PIC12C509A-04/SM only when the firmware is final; for development use the PIC12F509 flash-based pin-compatible alternative. Ensure decoupling capacitors of 0.1 uF are placed close to VDD and that unused I/O pins are configured as outputs or inputs with weak pull-up.
This page synthesizes distributor pricing, drop-in SOIJ-8 alternatives, comparison tables, and practical design notes not found on the manufacturer product page alone.
Drop-in alternatives for PIC12C509A-04/SM 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/SM (same form factor and footprint) β differing in Package, Core Architecture, Program Memory Size, Timers, Data EEPROM.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC12C509A-04I/SM
β Drop-Inβ In Stock
$0.93 / Unit
View Datasheet βPIC12C509A-04E/SM
β Drop-Inβ In Stock
$1.55 / Unit
View Datasheet βPIC12C508A-04/SM
β Drop-Inπ Reference alternative (not in catalog)
PIC12C509-04/SM
β Drop-Inπ Reference alternative (not in catalog)
PIC12C508A-04I/SM
β Drop-Inβ In Stock
$1.05 / Unit
View Datasheet βPIC12C508-04/SM
β Drop-Inπ Reference alternative (not in catalog)
PIC12C509A-04/SM Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller |
| Core Architecture | PIC12 (Harvard, RISC) |
| Instruction Set | 33 single-word instructions |
| Instruction Cycle Time | 1 us at 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.5 KB (1024 x 12 words) |
| Data RAM | 41 bytes |
| Data EEPROM | Not present |
| Maximum Clock Frequency | 4 MHz |
| I/O Pins | 6 |
| Timers | 1 x 8-bit (TMR0) |
| ADC | None |
| Package | 8-SOIJ (SOIJ-8, 5.23 mm body) |
| Mounting Type | Surface Mount |
| Operating Temperature | 0C to +70C (commercial grade, no /I or /E suffix) |
| Supply Voltage (VDD) | 3.0 V to 5.5 V |
| Oscillator Modes | External RC, External Crystal, Internal 4 MHz RC |
| Watchdog Timer | Yes (with on-chip RC) |
| Special Features | Power-On Reset, SLEEP mode, code protection |
| RoHS Status | Compliant |
PIC12C509A-04/SM Pin Configuration
| Pin 1 | GP5/OSC1/CLKIN β Bidirectional I/O pin / oscillator input / external clock input |
| Pin 2 | GP4/OSC2/CLKOUT β Bidirectional I/O pin / oscillator output / clock output |
| Pin 3 | GP3/MCLR/VPP β Bidirectional I/O pin / Master Clear reset / programming voltage |
| Pin 4 | VSS β Ground reference |
| Pin 5 | VDD β Positive supply voltage (3.0 V to 5.5 V) |
| Pin 6 | GP2/T0CKI/INT β Bidirectional I/O pin / Timer0 clock input / external interrupt |
| Pin 7 | GP1 β Bidirectional I/O pin |
| Pin 8 | GP0 β Bidirectional I/O pin |
Typical Applications
PIC12C509A-04/SM is suitable for 6 applications: Battery-Powered Sensor Interface, Appliance Control Logic, Consumer Remote Transmitter, LED Lighting Controller, Toys and Hobby Electronics, Smart Sensor Edge Node.
Battery-Powered Sensor Interface
The PIC12C509A-04/SM is well-matched to low-cost sensor interfaces such as thermistor signal conditioning or thermopile readout, where the 4 MHz PIC12 RISC core delivers 1 MIPS in a tiny 8-SOIJ footprint. Its 41 bytes of RAM and 1.5 KB OTP program memory are sufficient for linearization look-up tables and averaging filters. The integrated 4 MHz internal RC oscillator eliminates an external resonator, reducing BOM cost, and the SLEEP mode with watchdog wake-up draws only a few microamperes, making the part ideal for 2xAA or coin-cell powered sensor nodes.
Recommended
Appliance Control Logic
Home appliances such as rice cookers, fans, coffee makers, and small kitchen devices use the PIC12C509A-04/SM as a compact state-machine controller. Its 33-instruction RISC core and 1 us instruction cycle enable tight event-response loops for relays, triacs, and keypad inputs, while the 6 GPIO pins comfortably drive a 7-segment LED or button matrix via charlieplexing. Operating from 3.0 V to 5.5 V and 0C to +70C, the part fits standard indoor appliance thermal envelopes.
Recommended
Consumer Remote Transmitter
IR remote controls and RF key-fobs commonly use the PIC12C509A-04/SM because of its tiny SOIJ-8 footprint, low SLEEP current, and adequate OTP memory for protocol state machines (NEC, RC5, custom). The 4 MHz internal RC oscillator plus a single output pin driving an IR LED through a transistor enables sub-$0.50 transmitter BOM cost. With watchdog wake-up, the part can idle in the nanoampere range until a button press.
Recommended
LED Lighting Controller
Decorative LED strings, indicator lights, and small PWM drivers benefit from the PIC12C509A-04/SM's 6 GPIO and 8-bit timer, which support multi-channel software PWM at audio noise-free frequencies. The 1.5 KB OTP memory can hold multi-pattern chase sequences, and the 3.0 V to 5.5 V supply range accommodates both 3.3 V logic-level and 5 V high-brightness LED chains. Commercial temperature range suits indoor luminaires.
Recommended
Toys and Hobby Electronics
Low-cost toys, robotics kits, and hobby electronics use the PIC12C509A-04/SM for compact, programmable behavior with a sub-$1 BOM target. The PIC12 RISC architecture is straightforward for beginners learning assembly or C, and the SOIJ-8 package fits inside the tightest enclosures. The integrated watchdog timer ensures toys do not 'lock up' when batteries are low, improving user experience.
Recommended
Smart Sensor Edge Node
Edge-of-network sensor nodes such as environmental monitors or simple alarm contacts leverage the PIC12C509A-04/SM's low power, OTP economy, and minimal 8-pin footprint. The part can wake on watchdog overflow, take a single ADC-free reading via comparator or discrete threshold, transmit a simple pulse via GPIO, and return to SLEEP - drawing only a few microamperes average. Pair with an external I2C sensor or EEPROM for smart sensor functionality.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509A-04/SM β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509A-04I/SM | PIC12C509A-04E/SM | PIC12C508A-04/SM | PIC12C509-04/SM | PIC12C508A-04I/SM |
|---|---|---|---|---|---|---|
| Package | 8-SOIJ | 8-SOIJ (same) | 8-SOIJ (same) | 8-SOIJ (same) | 8-SOIJ (same) | 8-SOIJ (same) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 1.5 KB OTP (1K x 12) | 1.5 KB OTP | 1.5 KB OTP | 0.75 KB OTP | 1.5 KB OTP | 0.75 KB OTP |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Data RAM | 41 bytes | 41 bytes | 41 bytes | 25 bytes | 41 bytes | 25 bytes |
| Operating Temperature | 0C to +70C | -40C to +85C | -40C to +125C | 0C to +70C | 0C to +70C | -40C to +85C |
| Supply Voltage | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V |
| I/O Pins | 6 | 6 | 6 | 6 | 6 | 6 |
Key Differentiators
- Wider commercial temperature range is not needed for indoor use (vs PIC12C509A-04I/SM)
- Maximum 1.5 KB OTP program memory in 8-pin package (vs PIC12C508A-04/SM)
- Successor part with active Microchip support (vs PIC12C509-04/SM)
Design Notes
Place a 0.1 uF decoupling capacitor as close as possible to the VDD pin (pin 5) of the PIC12C509A-04/SM. For battery-powered designs, add a bulk 1-10 uF capacitor near VDD to handle load transients when the internal RC oscillator or GPIO outputs switch. SLEEP current is typically under 1 uA at 3 V, so the supply filter does not need to be low-ESR - a standard X5R ceramic suffices.
Route the MCLR/VPP pin (pin 3) carefully. If using an in-circuit programmer, isolate MCLR from other circuitry or provide a programming header that disconnects the external pull-up during programming. Keep the oscillator traces (pins 1 and 2) short when using an external crystal or resonator; for internal RC mode, leave pins 1-2 as GPIO but disable the clock output bit to reduce EMI.
Because the PIC12C509A-04/SM uses OTP memory, the firmware is committed once and cannot be erased. Always prototype with the flash-based PIC12F509 (drop-in PCB pinout) before committing to OTP for production. Additionally, the 33-instruction PIC12 core does not have a hardware multiplier - if your code does heavy arithmetic, pre-compute constants or move to a PIC16 or PIC18 part.
Compliance Information
Per Microchip product page the SOIJ-8 package is lead-free and RoHS compliant. Not AEC-Q100 qualified - choose PIC12C509A-04E/SM with extended temp grade for automotive-adjacent designs.
