PIC12C509-04I/SM - 8-Bit 4MHz OTP MCU, 1.5KB | Microchip
MPN: PIC12C509-04I/SM ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.95 | $1.95 |
| 10 | $1.75 | $17.50 |
| 100 | $1.45 | $145.00 |
| 500 | $1.22 | $610.00 |
| 1,000 | $1.05 | $1,050.00 |
PIC12C509-04I/SM Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path, integrating a CPU core, program memory, data RAM, and peripherals. The PIC12C509 belongs to Microchip's baseline PIC10/12/16 family of OTP-based microcontrollers, which sit at the simplest end of the PIC architecture hierarchy: microcontroller -> embedded controller -> microprocessor -> semiconductor. Baseline PIC12 devices execute one instruction per 1us at 4 MHz and provide a minimal footprint solution for cost-sensitive, low-pin-count applications.
The PIC12C509-04I/SM operates at a clock frequency of up to 4 MHz with an instruction execution time of 1 microsecond, using a RISC instruction set of only 33 single-word instructions. It features a 12-bit program counter capable of addressing 1K x 12 of OTP, on-chip RC oscillator, and 6 general-purpose digital I/O pins. The OTP memory allows one-time field programming, lowering unit cost versus flash-based parts.
Internally, the device uses a Harvard architecture with separate program and data buses, a precision 4 MHz internal RC oscillator (no external crystal required), and a watchdog timer with on-chip RC oscillator for reliable unattended operation. Power consumption is approximately 2 mA typical at 5V/4 MHz and falls to microampere levels in SLEEP mode, making the part practical for battery-powered sensor and appliance designs.
Typical applications include simple timing and pulse generation, household appliance control (toasters, fans, coffee makers), battery chargers, LED drivers, security sensors, and any low-cost 6-I/O embedded task. The industrial temperature grade (-40C to +85C, suffix "I") broadens deployment into factory and outdoor enclosures.
When designing with the PIC12C509-04I/SM, note that OTP cannot be erased, so firmware must be fully verified before programming. For new designs or those requiring in-system reprogrammability, the pin-compatible PIC12F509 (Flash, 1.5KB) is typically preferred. For designs needing >1.5KB of code, consider PIC12C508A (512 words) or PIC16C5xx family with more I/O and memory.
This page consolidates distributor pricing, same-package drop-in alternatives, and practical design guidance drawn from the Microchip PIC12C509 datasheet family. Information not present in the verified datasheet is marked as for engineering review.
Drop-in alternatives for PIC12C509-04I/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 PIC12C509-04I/SM (same form factor and footprint) — differing in Core Architecture, Program Memory Size, I/O Pins, Instruction Execution Time, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12C509-04/SM
✅ Drop-In✓ In Stock
$1.87 / Unit
View Datasheet →PIC12C509A-04I/SM
✅ Drop-In✓ In Stock
$0.93 / Unit
View Datasheet →PIC12C509A-04I/SN
✅ Drop-In✓ In Stock
$0.92 / Unit
View Datasheet →PIC12C508A-04I/SM
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC12F508-I/SM
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12F509-I/SM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC10F200-I/P
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.28 / Unit
View Datasheet →PIC12C509-04I/SM Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM Size | 41 bytes |
| EEPROM Size | None (OTP only) |
| Maximum Clock Frequency | 4 MHz |
| Instruction Execution Time | 1 us at 4 MHz |
| Number of I/O Pins | 6 |
| Number of Instructions | 33 (single-word) |
| Operating Temperature Range | -40 C to +85 C (Industrial grade) |
| Package Type | 8-SOIJ (208 mil) |
| Mounting Type | Surface Mount |
| Oscillator | Internal 4 MHz RC |
| Watchdog Timer | Yes (on-chip RC) |
| RoHS Status | Compliant |
PIC12C509-04I/SM Pin Configuration
| Pin 1 | GP2/T0CKI — GPIO GP2 / Timer0 clock input (bidirectional) |
| Pin 2 | GP3/MCLR/VPP — GPIO GP3 (input-only) / Master Clear reset / programming voltage input |
| Pin 3 | GP4/OSC2 — GPIO GP4 / oscillator output (crystal mode) |
| Pin 4 | VSS — Ground reference |
| Pin 5 | GP0/OSC1 — GPIO GP0 / oscillator input (crystal mode) / ICSP DAT |
| Pin 6 | GP1 — GPIO GP1 / ICSP CLK |
| Pin 7 | VDD — Positive supply voltage |
| Pin 8 | GP5 — GPIO GP5 |
Typical Applications
PIC12C509-04I/SM is suitable for 7 applications: Household Appliance Control, Battery Charger State Machine, LED Driver / Lighting Controller, Security and PIR Sensor Interface, Industrial Timer and Pulse Generator, Toy and Hobby Electronics, Remote Control Replacement / Wireless Toy Key Fob.
Household Appliance Control
The PIC12C509-04I/SM's 1.5KB OTP memory and 6 I/O pins are sized precisely for simple toaster, kettle, fan, or coffee-maker control loops where one or two digital inputs (button, sensor) drive relay or triac outputs. The 4 MHz internal RC oscillator eliminates external crystal cost, and the industrial -40C to +85C grade handles kitchen thermal environments. Power consumption around 2 mA active is acceptable from mains-derived supplies, while the SLEEP mode below 10 uA supports battery-backed settings memory during mains loss.
Recommended
Battery Charger State Machine
For low-current NiCd or Li-ion chargers with simple CC/CV state transitions, the PIC12C509-04I/SM provides adequate program space for the algorithm and enough I/O for relay/LED control. The 4 MHz clock rate is sufficient to monitor Vbat at 1 kHz via comparator input and update PWM-style drive on a digital pin. Industrial temperature operation supports under-hood automotive and outdoor solar charger enclosures. The OTP memory ensures the production firmware cannot be accidentally altered by noise.
Recommended
LED Driver / Lighting Controller
The PIC12C509-04I/SM handles simple LED driver sequencing such as RGB color mixing, strobe patterns, or single-channel dimming via its 4 MHz instruction rate, which can output PWM at hundreds of Hz directly from GPIO. With 6 I/O pins, the MCU can drive up to 6 independent LED channels or take button inputs for mode selection. The industrial temperature grade supports outdoor luminaires. For new designs needing analog dimming or 1 MHz PWM, migrate to PIC12F1572 with CLC and PWM peripherals.
Recommended
Security and PIR Sensor Interface
The PIC12C509-04I/SM is well-suited for PIR motion sensor modules that translate the analog PIR signal into a digital trigger output. With 6 I/O pins, the MCU can monitor one PIR input, drive an alarm relay, blink a status LED, and accept arm/disarm buttons. The internal 4 MHz RC and watchdog timer provide reliable unattended operation. SLEEP mode current in the microampere range extends battery life for wireless PIR transmitters running on CR2032 cells.
Recommended
Industrial Timer and Pulse Generator
The PIC12C509-04I/SM's 33 single-word instructions and 1 us instruction cycle make it a versatile timer platform for industrial sequencing, delay-on-make, and pulse-train generation applications. With the TMR0 counter and watchdog timer, the MCU can produce long timing intervals up to several minutes while remaining responsive to external interrupts. Industrial -40C to +85C operation enables deployment in factory automation panels, while the 8-SOIJ package survives vibration better than DIP variants.
Recommended
Toy and Hobby Electronics
Cost-sensitive consumer toys benefit from the PIC12C509-04I/SM's small 8-pin SOIJ footprint, OTP-only memory that prevents firmware theft, and $1 BOM impact at volume. The 6 I/O pins drive motor drivers, sound chips, or LED arrays for educational robotics kits and simple animatronics. The internal RC oscillator removes crystal cost and reduces BOM. For toys requiring sound playback, an external piezo buzzer driven by PWM output from the MCU is sufficient for melody generation.
Recommended
Remote Control Replacement / Wireless Toy Key Fob
The PIC12C509-04I/SM fits low-cost 4-button RF key fobs where the MCU scans a button matrix and drives a SAW-based or OOK transmitter IC with simple on/off keying. The 4 MHz core encodes the button state into a 12-bit Manchester sequence at approximately 1 kbps, suitable for 433 MHz ASK transmitters. With OTP memory the firmware cannot be cloned by reading the program memory, providing IP protection for proprietary RF protocols. Industrial temperature grade supports automotive key fob use cases.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509-04I/SM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509-04/SM | PIC12C509A-04I/SM | PIC12C509A-04I/SN | PIC12C508A-04I/SM | PIC12F509-I/SM |
|---|---|---|---|---|---|---|
| Package | 8-SOIJ (SM) | 8-SOIJ (SM) | 8-SOIJ (SM) | 8-SOIC (SN) | 8-SOIJ (SM) | 8-SOIJ (SM) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 768 B OTP (-50%) | 1.5 KB Flash |
| RAM | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 25 bytes (-39%) | 41 bytes |
| Max Clock | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| I/O Pins | 6 | 6 | 6 | 6 | 6 | 6 |
| Memory Type | OTP | OTP | OTP | OTP | OTP | Flash (reprogrammable) |
| Operating Voltage | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.0 V to 5.5 V (wider) | 2.0 V to 5.5 V (wider) | 2.5 V to 5.5 V | 2.0 V to 5.5 V |
| Temperature Grade | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
Key Differentiators
- Sole 8-pin baseline PIC12 family part with 1.5KB OTP and 41-byte RAM in SOIJ (vs PIC12C508A-04I/SM)
- Wider voltage range and refined silicon (vs PIC12C509A-04I/SM)
- Programmable in-circuit via ICSP unlike basic PIC10F OTP (vs PIC10F200-I/P)
- Commercial temp grade variant for cost-sensitive consumer apps (vs PIC12C509-04/SM)
Design Notes
OTP (One-Time Programmable) memory cannot be erased. A single programming fault or bad firmware image permanently bricks the device. Always validate the HEX file by performing a verification read and a bench test on a windowed EPROM variant (PIC12C509-04/JW) or by using the Flash PIC12F509 to prototype before committing to OTP production. Order OTP devices only after firmware is fully signed off.
Estimated: Active current at 4 MHz, 5V is approximately 2 mA typical per Microchip datasheet characterization. Power dissipation is therefore ~10 mW at 5V/4 MHz, negligible thermal concern in the 8-SOIJ package. SLEEP mode current is single-digit microamperes; for sub-uA sleep, migrate to PIC12LF1822 or PIC10LF320 (nanoWatt XLP). Add a 100 nF ceramic decoupling capacitor as close as possible to VDD (Pin 7) and VSS (Pin 4) to suppress MCU switching noise on the supply rail.
Place the 8-SOIJ decoupling capacitor within 2 mm of the VDD pin to keep VDD ripple below 50 mV during GPIO transitions. If using an external crystal instead of the internal RC oscillator (XT or LP oscillator modes), route the OSC1/OSC2 traces short and symmetric with a ground guard ring. The MCLR/VPP pin (GP3) requires a 10 kohm pull-up to VDD for normal operation; the internal weak pull-up is disabled on GP3 by default, so an external resistor is mandatory unless ICSP is not used.
The PIC12C509 lacks a hardware UART, ADC, PWM, or I2C peripheral - these must be bit-banged in firmware. At 4 MHz instruction rate, software UART can reach ~9600 baud reliably; software I2C works up to 100 kHz. Engineers migrating from PIC16/18 families often overlook this absence. If the design requires hardware peripherals, choose the PIC12F1822 (ADC, PWM, UART, I2C) in a compatible 8-pin package.
Compliance Information
RoHS and lead-free compliance per Microchip product page and DigiKey/Mouser listings. PIC12C509 family is not AEC-Q100 qualified - automotive designs should use PIC16F1824 or PIC12F1822 with AEC-Q100 grade. REACH and conflict-mineral status reported as compliant by major distributors.
