PIC12C509-04/SM - 8-Bit 4MHz OTP MCU | Microchip | 8-SOIC
MPN: PIC12C509-04/SM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.96 | $2.96 |
| 10 | $2.66 | $26.60 |
| 100 | $2.37 | $237.00 |
| 500 | $2.11 | $1,055.00 |
| 1,000 | $1.87 | $1,870.00 |
PIC12C509-04/SM Overview
An 8-bit microcontroller (MCU) is a single-chip computer built around an 8-bit data path, a compact instruction set, on-chip program memory, working RAM, and configurable I/O. The PIC12C509 belongs to Microchip's foundational PIC12C sub-family of 8-pin mid-range devices, occupying the hierarchy: microcontroller -> embedded MCU -> 8-bit MCU -> PIC12 family -> PIC12C5xx OTP series -> semiconductor. These devices are favored for legacy designs, cost-sensitive consumer products, and applications where Flash reprogrammability is not required.
Key features include 25 mA source/sink capability per I/O pin (sufficient to drive small relays, LEDs, or power MOSFET gates directly), four selectable oscillator modes including a factory-calibrated internal 4 MHz RC oscillator, on-chip Power-on Reset (POR), and an instruction execution time of 1 microsecond at 4 MHz. The device is supported by a 33 single-word instruction set optimized for code density, and its 8-pin footprint enables compact PCB designs.
The PIC12C509 uses a Harvard-architecture RISC core with separate program and data buses. The 12-bit-wide instruction word delivers a typical 2:1 code compression over competing 8-bit architectures, allowing more functionality in the constrained 1.5 KB OTP. The OTP memory is programmed once via Microchip's ICSP (In-Circuit Serial Programming) interface and is not erasable; for field-updatable designs, the PIC12F509 (Flash-based successor) is recommended.
Typical applications include small appliance control (coffee makers, fans, remote-control toys), low-end sensor signal conditioning, simple LED drivers, and replacement of discrete logic glue in legacy industrial systems. The wide operating temperature range (commercial 0C to +70C) supports indoor commercial and light-industrial use.
When designing with this device, ensure that the selected oscillator mode is compatible with the application timing budget. Because the program memory is OTP, firmware must be fully validated before committing to production programming. The internal 4 MHz RC oscillator is factory-calibrated, eliminating external crystal components in cost-sensitive designs.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes compiled from manufacturer datasheets and authorized distributor listings, providing information gain beyond what a single datasheet or catalog entry offers.
Drop-in alternatives for PIC12C509-04/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 PIC12C509-04/SM (same form factor and footprint) — differing in Watchdog Timer, Program Memory Size, Operating Temperature Range, Timers, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12C509A-04/SM
✅ Drop-In✓ In Stock
$0.99 / Unit
View Datasheet →PIC12C509AT-04/SM
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC12C509-04/P
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC12C508-04/SM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C508A-04/SM
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC12C509-04/SM Maximum Ratings & Electrical Characteristics
| Manufacturer | Microchip Technology |
| Product Family | PIC® 12C |
| Core | 8-bit PIC RISC |
| Program Memory Size | 1.5 KB (1K x 12) OTP |
| RAM Size | 41 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle Time | 1 microsecond @ 4 MHz |
| I/O Pins | 6 |
| I/O Sink/Source Current | 25 mA per pin |
| Package / Case | 8-SOIJ (8-SOIC, 0.209" / 5.30 mm body width) |
| Mounting Type | Surface Mount |
| Oscillator Options | 4 selections (internal 4 MHz RC, external RC, crystal, LP) |
| Operating Temperature Range | 0C to +70C (commercial) |
| Instruction Set | 33 single-word instructions |
| Programming Method | ICSP (In-Circuit Serial Programming) |
| Power-on Reset | Yes (on-chip) |
| Watchdog Timer | Yes |
| RoHS Status | Compliant (per distributor listings) |
PIC12C509-04/SM Pin Configuration
| Pin 1 | GP5/OSC1/CLKIN — General-purpose I/O / oscillator input / external clock input |
| Pin 2 | GP4/OSC2/CLKOUT — General-purpose I/O / oscillator output / clock output |
| Pin 3 | GP3/MCLR/Vpp — General-purpose input / Master Clear reset (active low) / programming voltage input |
| Pin 4 | Vss — Ground reference |
| Pin 5 | GP2/T0CKI/INT/COUT — General-purpose I/O / Timer0 clock input / external interrupt / comparator output |
| Pin 6 | GP1/CIN-/ICSPCLK — General-purpose I/O / comparator negative input / ICSP clock |
| Pin 7 | GP0/CIN+/ICSPDAT — General-purpose I/O / comparator positive input / ICSP data |
| Pin 8 | Vdd — Positive supply voltage |
Typical Applications
PIC12C509-04/SM is suitable for 6 applications: Small Appliance Control, Remote Control and Toy Electronics, LED Driver and Lighting Controller, Sensor Signal Conditioning and Threshold Detection, Legacy Industrial Logic Replacement, Automotive Interior Accessories.
Small Appliance Control
The PIC12C509-04/SM fits small appliance control because its 4 MHz instruction execution provides sufficient speed for state-machine-based control loops, and its 6 I/O pins can directly drive relays, LEDs, triac gates, and user-interface buttons without external drivers. Each GPIO sinks/sources 25 mA - high enough to energize small 5V relays or indicator LEDs directly. The internal factory-calibrated 4 MHz RC oscillator eliminates external crystals, reducing BOM cost and PCB area in coffee makers, fans, toasters, and handheld vacuums. With 1.5 KB of OTP program memory, the device handles appliance timing patterns, button debouncing, and simple PWM routines. Trade-off: OTP memory means firmware must be fully debugged before production programming, increasing time-to-production if firmware changes are likely.
Recommended
Remote Control and Toy Electronics
The PIC12C509-04/SM is well-suited for remote control transmitters and electronic toys because its compact 8-pin SOIJ package enables miniature PCB designs while still providing 6 I/O pins for buttons, status LEDs, and IR or RF encoder output. The 1 microsecond instruction cycle at 4 MHz easily handles NEC, RC5, or custom IR protocols and supports real-time button scanning. The 25 mA per-pin drive can directly power an IR LED through a current-limiting resistor, eliminating the need for external transistor drivers. Internal 4 MHz RC oscillator eliminates crystal components, lowering BOM cost. Watchdog timer improves field reliability against ESD or low-battery brownouts common in consumer toys.
Recommended
LED Driver and Lighting Controller
The PIC12C509-04/SM drives LED-based lighting controllers and decorative light strings because its 6 GPIO pins, each rated at 25 mA source/sink, can directly drive multiple LEDs in parallel or interface to low-side MOSFET drivers for higher-current strings. The 4 MHz clock supports PWM dimming frequencies above the flicker fusion threshold (typically >100 Hz), enabling smooth brightness control. Its 1.5 KB OTP program memory accommodates chase patterns, fade routines, and simple scheduling logic. The internal 4 MHz RC oscillator simplifies board layout by removing external timing components. The 8-SOIJ surface-mount package supports automated pick-and-place assembly for high-volume decorative lighting production.
Recommended
Sensor Signal Conditioning and Threshold Detection
The PIC12C509-04/SM fits low-end sensor conditioning modules because its 4 MHz core and 33-instruction RISC set easily handle threshold comparisons, simple linearization math, and alarm flag generation from analog sensor inputs. With 6 I/O pins, the MCU can interface to multiple digital sensors (e.g., temperature switches, Hall-effect sensors) or one analog sensor via an external comparator. The internal 4 MHz RC oscillator provides timing stability sufficient for polling-based sampling at rates under 10 kHz. Watchdog timer and Power-on Reset improve reliability in unattended sensor nodes. Trade-off: no on-chip ADC, so analog measurement requires an external ADC or comparator IC.
Recommended
Legacy Industrial Logic Replacement
The PIC12C509-04/SM is commonly specified for replacing aging 8-pin logic ICs (4017, 4021, discrete gate arrays) in legacy industrial controllers because it offers programmable behavior in the same physical footprint. Engineers can replicate multi-chip discrete logic functions in a single MCU, reducing component count, improving reliability, and simplifying documentation. Its commercial 0C to +70C range and on-chip Power-on Reset support factory-floor enclosures. The 25 mA I/O drive can directly interface to 5V industrial logic. Watchdog timer recovers the system from transient EMI-induced lockups. OTP memory is acceptable here because industrial logic is typically firmware-stable for years.
Recommended
Automotive Interior Accessories
The PIC12C509-04/SM drives simple automotive interior accessories (ambient lighting controllers, seat heater switches, indicator chimes) because its 6 I/O pins and 25 mA drive handle button inputs, LED indicators, and small relay or MOSFET outputs. The 4 MHz instruction cycle manages debounced button scanning, beep generation, and timed PWM dimming of interior LEDs. Note: for under-hood or AEC-Q100-qualified designs, Microchip's PIC12C509A-04/SM or PIC16F series should be evaluated instead, as the standard PIC12C509-04/SM is commercial temperature grade. Trade-off: OTP memory means firmware bugs require hardware swap; Flash-based PIC12F509 is preferred for new automotive designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509-04/SM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509A-04/SM | PIC12C509AT-04/SM | PIC12C509-04/P | PIC12C508-04/SM | PIC12C508A-04/SM |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-SOIJ (5.30 mm body width) | 8-SOIJ (5.30 mm body width) | 8-SOIJ (5.30 mm body width) | PDIP-8 (through-hole) | 8-SOIJ (5.30 mm body width) | 8-SOIJ (5.30 mm body width) |
| Program Memory | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 768 bytes OTP | 768 bytes OTP |
| RAM Size | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 25 bytes | 25 bytes |
| Maximum Clock Frequency | 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 | OTP |
| Silicon Revision | Original (pre-A) | 'A' revision (improved calibration) | 'A' revision (tape and reel) | Original (pre-A), PDIP package | Original (pre-A), smaller memory | 'A' revision, smaller memory |
Key Differentiators
- Pin-compatible 'A' silicon revision with improved oscillator calibration (vs PIC12C509A-04/SM)
- Same die available in PDIP-8 through-hole package (vs PIC12C509-04/P)
- Larger program memory than the PIC12C508 family (vs PIC12C508-04/SM)
Design Notes
The PIC12C509-04/SM operates from a single Vdd supply (typical 2.5V to 5.5V per Microchip PIC12C5XX datasheet DS40139E; full min/max limits to be confirmed in datasheet revision). Place a 0.1 microfarad ceramic decoupling capacitor as close as physically possible to the Vdd pin (pin 8) to suppress digital switching noise. For applications with high-current peripherals driven by the same supply, add a 10 microfarad bulk capacitor near the IC. The internal 4 MHz RC oscillator draws additional current during operation; for battery-powered designs, consider using the LP oscillator mode with a 32.768 kHz crystal and waking the CPU via Watchdog Timer to minimize average current consumption.
The 8-SOIJ (SOIC-8 with 0.209 inch / 5.30 mm body width) package requires a standard SOIC-8 land pattern with 1.27 mm pin pitch. Keep traces to the MCLR/Vpp pin (pin 3) short to minimize stray capacitance that can interfere with ICSP programming; long traces coupled to switching nodes can cause programming failures. Place the ICSP connector or test points near the MCU to reduce programming cable length. If using an external crystal or resonator between pins 1 and 2, keep the crystal traces short and surrounded by a ground guard ring to reduce EMI susceptibility. Decoupling capacitor on Vdd should be on the same PCB side as the IC, not routed through vias if possible.
Three common pitfalls to avoid with the PIC12C509-04/SM: (1) OTP program memory cannot be erased - any firmware bug shipped to production becomes a hardware recall. Fully validate firmware using a Flash-based PIC12F509 prototype before committing to OTP programming. (2) The MCLR pin (pin 3) is shared with the GP3 general-purpose input; GP3 is input-only, so you cannot drive MCLR low via firmware. If using MCLR as a reset, ensure no code path attempts to drive pin 3 as an output. (3) The internal 4 MHz RC oscillator is factory-calibrated but its frequency drifts with Vdd and temperature - for time-critical applications (UART baud-rate accuracy, infrared carrier frequency), use an external crystal oscillator mode rather than the internal RC.
Compliance Information
RoHS and lead-free compliance per Microchip product documentation and distributor listings. Not AEC-Q100 qualified; for automotive applications, evaluate AEC-Q100-qualified PIC12 variants. Commercial temperature grade (0C to +70C) only.
