PIC12C509/JW - 8-Bit 4MHz EPROM MCU, 1.5KB | Microchip
MPN: PIC12C509/JW ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $6.1 | $3,050.00 |
| 1,000 | $5.45 | $5,450.00 |
PIC12C509/JW Overview
A PIC microcontroller is a compact 8-bit RISC-based CMOS MCU built around a Harvard architecture with separate program and data buses. The PIC12C5xx family that PIC12C509/JW belongs to is the lowest pin-count and lowest cost tier of the classic PIC12 line, designed for glue logic replacement, simple state machines, and space-constrained embedded control. The 12-bit instruction width keeps the core simple, while the reduced instruction set (33 single-word, single-cycle instructions) makes timing predictable for interrupt-driven and polled firmware designs.
Key features of the PIC12C509/JW include 5 general-purpose I/O pins (25 mA source/sink per pin), an 8-bit real-time clock/counter (TMR0) with an 8-bit programmable prescaler, a Watchdog Timer (WDT) with its own on-chip RC oscillator, a Power-on Reset (POR), a Device Reset Timer (DRT), and four selectable oscillator modes including the internal 4 MHz RC oscillator with programmable calibration. The part is fully static and supports a DC to 4 MHz operating range across the commercial temperature grade (0C to +70C).
The architecture is RISC with 33 single-word/single-cycle instructions, 2-level hardware stack, and direct/indirect addressing modes. EPROM-based program memory with 1,000,000 erase/write endurance makes the JW variant ideal for development. Programmable code protection is supported, and the device can be erased by exposing the quartz window to UV light, then re-programmed on standard EPROM programmers - this is the key reason /JW parts remain in service for engineering prototypes and small production runs.
Typical applications for the PIC12C509/JW include personal care appliances, simple IR remote control transmitters, low-end consumer toys, automotive body electronics sub-modules, battery chargers, and any embedded design that benefits from a sub-$1 8-pin MCU. It also functions as a programmable logic replacement, timer sequencer, or PWM controller. The windowed CDIP-8 package is intentionally chosen for prototype re-programmability rather than high-volume SMT manufacturing.
When designing with this part, note that JW ceramic parts are NOT recommended for new high-volume designs - Microchip recommends the OTP PIC12C509A in PDIP/SOIC or migrating to the PIC10F/12F Flash families. The /JW is reserved for development, evaluation, and legacy support. Always verify the oscillator selection bit setting (RC vs XT vs LP vs HS) and place a 0.1uF decoupling capacitor close to VDD.
This page synthesizes distributor pricing, drop-in compatible alternatives, and practical design notes not found in the standalone manufacturer datasheet, giving engineers a single source for lifecycle status, comparison data, and procurement guidance.
Drop-in alternatives for PIC12C509/JW — 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/JW (same form factor and footprint) — differing in Core Architecture, Mounting Type, Program Memory Size, Program Memory Type, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12C509A/JW
✅ Drop-In✓ In Stock
$9.4 / Unit
View Datasheet →PIC12C509-04/JW
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C509-04I/JW
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C509-04E/JW
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C509-04E/JWG
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F509-I/P
✅ Drop-In✓ In Stock
$0.86 / Unit
View Datasheet →PIC12C509/JW Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-Bit |
| Core Architecture | RISC |
| Maximum CPU Speed | 4 MHz |
| Program Memory Type | EPROM (UV-erasable, windowed) |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM Size | 41 bytes |
| Data EEPROM | 0 bytes (none on this family) |
| Number of I/O Pins | 5 |
| I/O Source/Sink Current | 25 mA per pin |
| Peripherals | POR, WDT, DRT, TMR0 with 8-bit prescaler |
| Supply Voltage (Vdd) | 2.5 V to 5.5 V |
| Operating Temperature | 0C to +70C (Commercial) |
| Package | 8-pin CDIP (windowed ceramic DIP) |
| Mounting Type | Through-Hole |
| Instruction Set | 33 single-word/single-cycle instructions |
| Stack Depth | 2 levels (hardware) |
| Oscillator Modes | RC, XT, LP, HS (4 selections, internal 4 MHz RC with calibration) |
| Code Protection | Programmable |
| Erase/Write Endurance | 1,000,000 cycles (EPROM) |
PIC12C509/JW Pin Configuration
| Pin 1 | VDD — Positive supply voltage (2.5V to 5.5V) |
| Pin 2 | GP5/OSC1/CLKIN — General-purpose I/O / oscillator input / external clock input |
| Pin 3 | GP4/OSC2 — General-purpose I/O / oscillator output |
| Pin 4 | GP3/MCLR — General-purpose input only / Master Clear reset (active low) |
| Pin 5 | GP2/T0CKI — General-purpose I/O / Timer0 clock input |
| Pin 6 | GP1 — General-purpose I/O |
| Pin 7 | GP0 — General-purpose I/O |
| Pin 8 | VSS — Ground reference |
Typical Applications
PIC12C509/JW is suitable for 7 applications: IR Remote Control Transmitter, Personal Care Appliance Controller, Automotive Body Electronics Sub-Module, Programmable Logic Replacement (Glue Logic MCU), Low-Cost Battery Charger Controller, Toy and Consumer Novelty Electronics, Hobbyist and Educational Development Platform.
IR Remote Control Transmitter
The PIC12C509/JW is well suited to low-cost IR remote control transmitters where the EPROM-based JW package is used for firmware iteration during development. Its 4 MHz instruction rate is fast enough to generate 38 kHz / 40 kHz / 56 kHz carrier frequencies for RC5, NEC, and Sony SIRC protocols by toggling a GPIO with software timing, while the 25 mA I/O source/sink directly drives the IR LED through a current-limiting resistor without an external transistor. The 5 GPIO pins provide VDD, VSS, one button input (or matrix key), and one IR LED output, with two pins free for the internal oscillator. Power-on Reset and Watchdog Timer guarantee the transmitter recovers from brown-out or static-discharge lockups. Total BOM for a 5-button remote is under $1, with the PIC12C509/JW dominating as the only active component alongside the IR LED and a few passives.
Recommended
Personal Care Appliance Controller
The PIC12C509/JW fits personal care appliances such as electric toothbrushes, hair dryers, and shaver control boards where a small 8-pin MCU is needed to drive a motor, time a session, and read a few buttons. The 25 mA per-pin drive directly switches low-side MOSFET gates or small relay coils, and the 2.5V-5.5V supply range accommodates 2xAA / 1xLi-ion battery chemistries without an additional LDO. The 4 MHz internal RC oscillator eliminates the external crystal cost, and the Watchdog Timer prevents firmware lock-up in vibration-rich environments. Production designs should migrate to the PIC12F509-I/P (Flash, 100K cycles, ICSP), but the PIC12C509/JW is the right choice for early prototypes where the JW window allows quick EPROM re-programming during EMC and motor-drive tuning.
Recommended
Automotive Body Electronics Sub-Module
In automotive body electronics - such as a single-function timer relay for interior lights, a wash-wipe controller, or a seat-belt reminder buzzer - the PIC12C509/JW delivers a minimal-footprint 8-bit MCU that operates across the 2.5V-5.5V range after the upstream 12V battery is regulated. The 5 GPIO pins handle 2 inputs (button or sensor) and 3 outputs (relay coil, status LED, buzzer), and the 1.5 KB EPROM fits the typical state-machine firmware (less than 800 instructions) used in these sub-modules. The Watchdog Timer with its own internal RC oscillator is critical in the automotive electrical environment because it forces a controller reset if main-clock noise or EMI corrupts program flow. The /JW windowed package is used for engineering validation and EMC re-tuning; production typically uses the PIC12C509A-04E/JW (extended temperature grade, -40C to +125C).
Recommended
Programmable Logic Replacement (Glue Logic MCU)
The PIC12C509/JW is often used to replace a small PLD, a 74HC-series logic gate cluster, or a 555-timer in designs that need a few microseconds of programmable delay, a state machine, or a custom waveform. With 5 GPIO, 1.5 KB EPROM, and a 4 MHz CPU (1 us instruction cycle), the part can implement any 4-state sequence in firmware, plus a 25 mA high-current output to drive the downstream load directly. The JW windowed ceramic CDIP package is preferred for development because the EPROM can be erased with a 20-minute UV exposure and re-flashed during logic tuning. Once the firmware is finalized, the design is ported to the PIC12C509A in PDIP or the PIC12F509-I/P Flash version for production - both are pin-compatible 8-pin DIP packages.
Recommended
Low-Cost Battery Charger Controller
The PIC12C509/JW suits simple single-chemistry battery chargers (NiMH, Li-ion with external supervisor) where the MCU monitors charge current via an ADC-less comparator input, controls a low-side MOSFET to switch the charger on/off, and blinks a status LED. Its 2.5V-5.5V operating range covers 1xLi-ion and 2xAA NiMH packs, and the 4 MHz internal RC oscillator eliminates an external crystal, reducing the BOM to the PIC, the MOSFET, a sense resistor, and a handful of passives. The 1.5 KB EPROM comfortably fits the CC/CV state machine, timeout logic, and temperature fold-back, while the 41 bytes RAM handles the ADC-free control variables. Production typically migrates to the PIC12F509-I/P or PIC10F222 for cost reduction.
Recommended
Toy and Consumer Novelty Electronics
In talking toys, LED blink-pattern novelties, and small sound-effect modules, the PIC12C509/JW provides a sub-$1 8-bit MCU with enough program memory for short voice-table lookups, PWM-driven LED patterns, and button-triggered state machines. The 25 mA per-pin source/sink directly drives RGB LEDs and small piezo speakers without external drivers, and the internal 4 MHz RC oscillator keeps the BOM small (no external crystal or resonator). The Watchdog Timer prevents firmware lock-up if the toy is dropped or the battery bounces, ensuring the toy always recovers to a known state. The /JW windowed CDIP package is used for prototype firmware development; production migrates to the PIC12C509A in PDIP or the PIC12F509-I/P Flash equivalent.
Recommended
Hobbyist and Educational Development Platform
The PIC12C509/JW is a classic teaching platform for 8-bit MCU fundamentals - the 33 single-word/single-cycle RISC instruction set, the 2-level hardware stack, and the 12-bit instruction word are all visible in a small 1.5 KB program memory footprint that fits comfortably on a single page of disassembly. The JW windowed ceramic CDIP allows students to erase and re-program the part hundreds of times with a standard EPROM programmer and a UV eraser, teaching the full lifecycle of an EPROM-based MCU. The internal 4 MHz RC oscillator avoids the complexity of external crystal selection, and 5 GPIO pins are enough to demonstrate blinking LEDs, button debouncing, and software PWM. Modern courses typically transition to the PIC12F509-I/P or PIC10F200, but the PIC12C509/JW remains a useful reference for the historical PIC12C5xx architecture.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509/JW — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509A/JW | PIC12C509-04/JW | PIC12C509-04I/JW | PIC12C509-04E/JW | PIC12C509-04E/JWG | PIC12F509-I/P |
|---|---|---|---|---|---|---|---|
| Package | 8-CDIP (windowed) | 8-CDIP (windowed) - same | 8-CDIP (windowed) - same | 8-CDIP (windowed) - same | 8-CDIP (windowed) - same | 8-CDIP (windowed) - same | 8-PDIP (non-windowed) - same footprint |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Program Memory Type | EPROM (UV-erasable) | EPROM (UV-erasable) | EPROM (UV-erasable) | EPROM (UV-erasable) | EPROM (UV-erasable) | EPROM (UV-erasable) | Flash (100K cycles) |
| Program Memory Size | 1.5 KB (1K x 12) | 1.5 KB | 1.5 KB | 1.5 KB | 1.5 KB | 1.5 KB | 1.5 KB |
| RAM Size | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes |
| Maximum CPU Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| I/O Pins | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
| Operating Temperature | 0C to +70C (Commercial) | 0C to +70C | 0C to +70C | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +125C (Extended, Pb-free) | -40C to +85C (Industrial) |
Key Differentiators
- Windowed ceramic CDIP allows UV-erasable reprogramming for development (vs PIC12C509A-04/P (OTP PDIP, non-windowed))
- Active product line in 2026 for legacy and prototyping support (vs Generic 8-bit OTP MCU competitors (e.g., ATtiny from Microchip/Atmel))
- 25 mA per-pin source/sink directly drives LEDs and small relays (vs PIC10F200-I/P (smaller 6-pin SOT-23 Flash MCU))
Design Notes
The PIC12C509/JW is an EPROM-based part with a UV window - it CANNOT be reprogrammed in-circuit. Any firmware change requires a UV eraser cycle (typically 20 minutes) and a standard EPROM programmer. For development cycles faster than 1 per day, use the PIC12F509-I/P (Flash, ICSP) or the PIC12C509A in a non-windowed package. Also note: the JW ceramic CDIP is not RoHS compliant in most lot histories because of the ceramic frit and quartz-window sealing process; verify with Microchip's material declaration before using in RoHS-bound products.
Place a 0.1uF decoupling capacitor as close as physically possible to the VDD pin (pin 1) and the VSS pin (pin 8), with the loop area minimized. If the design uses the internal 4 MHz RC oscillator, a bulk capacitor (1uF to 10uF) is also recommended at the supply rail. The PIC12C509 has no internal LDO - the VDD range is 2.5V-5.5V - so any upstream supply must be regulated. Estimated: with VDD = 5V, all GPIO inputs at VDD, all outputs unloaded, the typical supply current is approximately 1.8 mA at 4 MHz, which scales linearly with clock and is dominated by the internal oscillator.
When laying out the 8-pin CDIP footprint, allow extra board real estate around the part for the UV-window erase tool - the quartz window sits on top of the ceramic body, and the eraser lamp must physically clear the surrounding components. For prototype boards, leave 5 mm clearance above the part. If you plan to migrate to the Flash-based PIC12F509-I/P in the same PCB layout, verify the PDIP-8 footprint is identical (it is - both are JEDEC MS-001 8-pin PDIP 0.300 inch row spacing).
GP3 is input-only and shares its pin with the MCLR (Master Clear) reset function. If you use GP3 as a digital input, you must disable the MCLR function in the configuration word (set the MCLRE bit to 0) and provide an internal weak pull-up via the WPU option, otherwise the MCLR function will override the input. This is the most common firmware bug in PIC12C5xx designs that use all 5 available GPIO pins. Estimated: with MCLRE=0 and WPU=1, the input leakage on GP3 is under 1 uA at 5V.
Compliance Information
RoHS and lead-free status of the /JW windowed ceramic CDIP package is [DATA_NEEDED] - ceramic windowed DIP packages historically contain lead in the ceramic frit, but Pb-free /JWG variants exist. AEC-Q100 automotive qualification is not applicable; the PIC12C509 is commercial/industrial only. Microchip's product page recommends migrating to PIC12F509 Flash parts for new automotive or RoHS-bound designs.
