PIC12LC509AT-04I/SM - 8-bit 4MHz OTP MCU, 1.5KB | Microchip
MPN: PIC12LC509AT-04I/SM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.43 | $1.43 |
| 10 | $1.29 | $12.90 |
| 100 | $1.1 | $110.00 |
| 500 | $0.95 | $475.00 |
| 1,000 | $0.85 | $850.00 |
PIC12LC509AT-04I/SM Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, volatile working memory, and configurable peripheral blocks into one package. The PIC10/12 family sits at the low end of Microchip's 8-bit PIC microcontroller portfolio, designed for cost-sensitive, pin-limited applications such as appliance controls, sensor signal conditioning, and battery-powered logic replacements. The PIC architecture uses a RISC instruction set with only 33 single-word instructions, allowing most instructions to execute in one instruction cycle (200 ns at 20 MHz / 1 us at 4 MHz).
Key features include a programmable 8-bit prescaler plus TMR0 timer/counter, Power-On Reset (POR), Device Reset Timer (DRT), a Watchdog Timer (WDT) with its own on-chip RC oscillator, and user-programmable code protection. The OTP program memory allows one-time field programming while keeping unit cost lower than Flash-based equivalents. Brown-out and power-on reset blocks hold the device in a known state on cold starts, and the internal oscillator option reduces external component count.
The PIC12LC509A architecture uses a Harvard-design CPU with separate program and data paths. The OTP program memory is 12 bits wide to match the instruction format, while the data RAM is organized as general-purpose file registers plus special-function registers mapped into bank 0. The 6 I/O pins are multiplexed with the GP0..GP5 ports and can be individually configured as digital inputs or outputs via the TRISGPIO register. Internal peripherals include the TMR0 timer with an 8-bit programmable prescaler that can be clocked from the system oscillator, the external GP2/T0CKI pin, or the internal WDT RC oscillator.
Typical applications include low-cost logic replacement, smart sensors and battery-powered instrumentation, white goods and appliance user-interface controllers, simple RC-servo or stepper pulse generators, and personal-care or hobby devices. Designers choose this part when small package size, low power, and minimal external components outweigh the need for reprogrammability or analog peripherals.
A key design consideration: the OTP memory cannot be erased and rewritten. Engineers should plan prototypes around the Flash-based PIC12F509 (same die family, Flash, same pinout) and migrate to this OTP part only once firmware is frozen. Decoupling on VDD should be a 100 nF ceramic placed within 5 mm of the pin, and unused inputs must be tied to a defined logic level (never floating) to avoid shoot-through current on the I/O drivers.
This page synthesizes distributor pricing, drop-in alternatives, and design considerations for the PIC12LC509AT-04I/SM that are not aggregated on the manufacturer product page.
Drop-in alternatives for PIC12LC509AT-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 PIC12LC509AT-04I/SM (same form factor and footprint) — differing in Program Memory Size, I/O Pins, Instruction Execution Time, Instruction Set, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12LC509AT-04/SM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12LC509A-04I/SM
✅ Drop-In✓ In Stock
$0.71 / Unit
View Datasheet →PIC12C509A-04I/SM
✅ Drop-In✓ In Stock
$0.93 / Unit
View Datasheet →PIC12C509AT-04I/SM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F509-I/SM
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12F509T-I/SM
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12F508-I/SM
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12LC509AT-04I/SM Maximum Ratings & Electrical Characteristics
| Core | 8-bit PIC RISC |
| Instruction Set | 33 single-word instructions |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM | 41 bytes |
| EEPROM | None (OTP only) |
| Maximum CPU Frequency | 4 MHz |
| Supply Voltage (VDD) | 2.5 V to 5.5 V |
| I/O Pins | 6 (GP0..GP5) |
| Timers | TMR0 with 8-bit programmable prescaler |
| Watchdog Timer | Yes (independent on-chip RC oscillator) |
| Power-On Reset | Yes (POR + DRT) |
| Code Protection | User-programmable |
| Package | 8-pin SOIJ (208 mil) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (industrial, 'I') |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC12LC509AT-04I/SM Pin Configuration
| Pin 1 | GP5/OSC1/CLKIN — Bidirectional I/O / oscillator input / external clock input |
| Pin 2 | GP4/OSC2/CLKOUT — Bidirectional I/O / oscillator output / clock output |
| Pin 3 | GP3/MCLR/VPP — Bidirectional I/O / Master Clear (reset) / programming voltage input |
| Pin 4 | VSS — Ground reference |
| Pin 5 | GP0 — Bidirectional I/O port bit 0 |
| Pin 6 | GP1 — Bidirectional I/O port bit 1 |
| Pin 7 | GP2/T0CKI — Bidirectional I/O / TMR0 external clock input |
| Pin 8 | VDD — Positive supply voltage (2.5 V to 5.5 V) |
Typical Applications
PIC12LC509AT-04I/SM is suitable for 6 applications: Low-Cost Logic Replacement, Battery-Powered Smart Sensor, White Goods / Appliance UI Controller, RC Servo / Stepper Pulse Generator, Personal Care / Hobby Device Controller, Industrial Sensor Interface Module.
Low-Cost Logic Replacement
The PIC12LC509AT-04I/SM is well-suited as a drop-in replacement for discrete CMOS logic gates or small PLAs in cost-sensitive designs. Its 4 MHz core, 1.5 KB OTP program memory, 41 B RAM, and 6 I/O pins cover the full timing logic of typical glue-logic replacements such as signal multiplexing, latch functions, monostable multivibrators, or simple state machines. Designers benefit from the LC variants 2.5 V minimum supply, which allows direct 3.3 V system integration and battery operation. Compared to a 74HC00 quad NAND, the PIC12LC509AT-04I/SM adds programmability at lower PCB area and competitive unit cost at qty 1000.
Recommended
Battery-Powered Smart Sensor
The PIC12LC509AT-04I/SM fits battery-powered sensor signal-conditioning applications thanks to its low-power CMOS core, 2.5 V to 5.5 V supply, and only 6 I/O pins. A typical circuit uses two I/O pins for an SPI/I2C-style digital sensor, one for a wake-up interrupt, and one for an indicator LED driver. The Watchdog Timer with its dedicated on-chip RC oscillator lets the firmware sleep between sensor reads, minimizing quiescent current. Compared to an 8-bit Flash MCU like the PIC12F509, this OTP part saves unit cost in volume but loses the ability to do firmware field updates.
Recommended
White Goods / Appliance UI Controller
The PIC12LC509AT-04I/SM is a common choice for white-goods appliance user-interface controllers where simple button inputs drive LED indicators or buzzer outputs. The 6 I/O pins comfortably handle 4 buttons plus 2 indicator LEDs (or 2 buttons plus 4 LEDs). The 4 MHz core and 1.5 KB OTP hold button-debounce state machines, mode-selection logic, and basic timing functions. The industrial -40C to +85C temperature range supports refrigerator, dishwasher, and washing-machine environments without thermal derating. Compared to a discrete 555-timer plus logic gate implementation, the LC509A reduces part count and BOM cost.
Recommended
RC Servo / Stepper Pulse Generator
The PIC12LC509AT-04I/SMs TMR0 timer with its 8-bit programmable prescaler, 4 MHz CPU clock, and 6 I/O pins make it suitable for hobby and low-cost commercial pulse-train generators for RC servos or stepper motors. The 200 ns instruction cycle supports servo refresh rates up to 50 Hz across multiple channels using software PWM. Pin count of 6 supports 2-axis unipolar stepper control or 4-channel servo drive. The PICs deterministic instruction timing is more reliable than discrete RC timers and costs less than a dedicated motion controller.
Recommended
Personal Care / Hobby Device Controller
The PIC12LC509AT-04I/SM serves as a low-cost controller in personal care devices (electric toothbrush, hair trimmer) and hobby electronics (LED blinky toys, model-train accessories). Its 2.5 V minimum supply allows direct 2x AA or 2x AAA battery operation, and the industrial temperature range survives bathroom or outdoor thermal swings. The 1.5 KB OTP holds small state machines for switch inputs, LED/H-bridge outputs, and battery-low indicators. Designers use this part because the OTP cost beats Flash at high volume, and the SOIJ package fits into tight enclosures.
Recommended
Industrial Sensor Interface Module
The PIC12LC509AT-04I/SM operates as a simple protocol-translator or sensor-interface module in industrial systems, where its -40C to +85C industrial range, 2.5 V to 5.5 V supply, and 6 I/O pins support one-wire or UART bridging functions. The PIC RISC cores deterministic timing is well-suited for software UART bit-banging at common baud rates up to 9600 bps. Power-On Reset and the Watchdog Timer keep the module recoverable in electrically noisy industrial cabinets. Compared to a generic UART bridge IC, the LC509A offers programmable flexibility for custom protocols.
Recommended
Recommended Products Summary
Engineering reference data for PIC12LC509AT-04I/SM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12LC509AT-04/SM | PIC12LC509A-04I/SM | PIC12C509A-04I/SM | PIC12F509-I/SM |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-pin SOIJ (SM, 208 mil) | 8-pin SOIJ (SM, 208 mil) - same | 8-pin SOIJ (SM, 208 mil) - same | 8-pin SOIJ (SM, 208 mil) - same | 8-pin SOIJ (SM, 208 mil) - same |
| Program Memory | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB Flash |
| CPU Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| RAM | 41 B | 41 B | 41 B | 41 B | 41 B |
| Supply Voltage | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 3.0 V to 5.5 V | 2.0 V to 5.5 V |
| Operating Temperature | -40C to +85C (industrial) | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +85C (industrial) | -40C to +85C (industrial) |
| Memory Type | OTP (one-time programmable) | OTP | OTP | OTP | Flash (reprogrammable) |
| I/O Pins | 6 | 6 | 6 | 6 | 6 |
Key Differentiators
- Lowest voltage drop-in for battery designs in the PIC12C509A family (vs PIC12C509A-04I/SM)
- Industrial temperature range vs commercial-temperature sibling (vs PIC12LC509AT-04/SM)
- OTPs cost advantage over Flash sibling at high volume (vs PIC12F509-I/SM)
Design Notes
The PIC12LC509AT-04I/SM uses OTP memory, so firmware bugs cannot be fixed in the field. Always prototype with the Flash-based PIC12F509-I/SM (same 8-pin SOIJ footprint and pinout) and migrate to the OTP LC509A only after the firmware is fully validated and frozen. Designing the SOIJ footprint to accept either part from the start allows a painless transition.
Place a 100 nF (0.1 uF) ceramic decoupling capacitor within 5 mm of the VDD pin (pin 8) to suppress switching noise from the internal oscillator and I/O transitions. For battery-powered designs, add a 10 uF bulk capacitor at the battery terminals. Unused I/O pins (GP0..GP5) must be configured as outputs or tied to VDD/VSS through a resistor - never left floating - to avoid shoot-through current in the input buffer that can drain the battery.
The 8-pin SOIJ package has a 208 mil body width, slightly wider than a 150 mil SOIC. Confirm the PCB land pattern matches Microchip package drawing C04-068 for SOIJ, otherwise an SOIC footprint will not accept the LC509A. The exposed thermal pad is not present on this 8-pin part, but a continuous ground pour under the package reduces EMI from the internal oscillator.
If using an external crystal or resonator on OSC1/OSC2 (pins 1 and 2), keep the trace length to each oscillator pad under 5 mm and surround the oscillator traces with a ground pour. The MCLR/VPP pin (pin 3) requires a 10 kohm pull-up to VDD for normal operation; in-circuit serial programming (ICSP) is performed by driving this pin to ~13 V briefly during programming.
Compliance Information
RoHS compliant per Microchip product page and LCSC listing for C628855. MSL Level 1 per JEDEC J-STD-020. Industrial -40C to +85C temperature grade. Not AEC-Q100 qualified; not recommended for automotive safety-critical applications.
