PIC12C509T-04I/SM - 8-Bit 4MHz MCU 1.5KB OTP | Microchip
MPN: PIC12C509T-04I/SM β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.28 | $12.80 |
| 100 | $1.07 | $107.00 |
| 500 | $0.92 | $460.00 |
| 1,000 | $0.81 | $810.00 |
| 2,500 | $0.74 | $1,850.00 |
PIC12C509T-04I/SM Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, data RAM, and peripherals onto one die, optimized for deterministic control tasks. The PIC12C509 family belongs to Microchip's baseline PIC12C architecture, which uses a RISC-like instruction set with only 33 single-word/single-cycle instructions. This positions the PIC12C509 at the bottom of the PIC family hierarchy (baseline PIC12 -> mid-range PIC16 -> enhanced mid-range PIC16 -> PIC18 -> PIC24/dsPIC), offering the smallest package count and lowest cost for cost-sensitive, space-constrained applications.
Key features include a 2.5V to 5.5V supply voltage range that allows direct operation from a single lithium cell or 3.3V/5V regulated rails, 200 ns instruction execution time, a programmable code protection bit, and an internal RC oscillator that eliminates the need for external clock components. The OTP program memory enables fast prototyping and short production runs without the tooling investment required for mask-ROM parts.
Architecturally, the PIC12C509 uses a 12-bit instruction word with a two-stage pipeline, separate instruction and data buses (Harvard architecture), and a hardware stack for subroutine nesting. The 6 I/O pins are multiplexed with the GP3 input and the MCLR reset, providing flexible pin assignment for digital I/O, timer-driven events, and external interrupts.
Typical applications include consumer appliance control, battery-powered sensor nodes, automotive interior accessories, LED driving, simple motor control, and replaceable logic in legacy designs. The wide voltage range and industrial temperature grade make it especially well-suited for harsh-environment embedded modules.
When designing with this device, allocate sufficient OTP programming margin for late-stage firmware changes and ensure the GP3 pin is configured correctly because it is input-only. The internal oscillator is factory-trimmed but allows no further in-circuit calibration, so timing-sensitive designs should use the external oscillator mode.
This page synthesizes distributor pricing, drop-in alternatives from the PIC12C5xx family, and practical design notes not found in the manufacturer datasheet alone, giving engineers a single reference for cross-referencing the part against PIC12C509A and PIC12C508A family variants.
Drop-in alternatives for PIC12C509T-04I/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 PIC12C509T-04I/SM (same form factor and footprint) β differing in Core Architecture, Program Memory Size, I/O Pins, Data EEPROM, Instruction Execution Time.
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-04/SM
β Drop-Inβ In Stock
$0.99 / Unit
View Datasheet βPIC12C509-04E/SM
β Drop-Inπ Reference alternative (not in catalog)
PIC12C509-04I/SM
β Drop-Inπ Reference alternative (not in catalog)
PIC12C508A-04I/SM
β Drop-Inβ In Stock
$1.05 / Unit
View Datasheet βPIC10F200T-I/OT
β Drop-Inπ Reference alternative (not in catalog)
PIC12C509T-04I/SM Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC baseline |
| Instruction Set Width | 12-bit |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.5 KB (1K x 12) |
| Data RAM | 41 bytes |
| Data EEPROM | None |
| Maximum CPU Frequency | 4 MHz |
| Instruction Execution Time | 200 ns (at 20 MHz clock input equivalent); 1 us at 4 MHz internal |
| Supply Voltage Range | 2.5 V to 5.5 V |
| I/O Pins | 6 (GP0-GP5, with GP3 input-only) |
| Timers | 1 x 8-bit (TMR0) |
| Watchdog Timer (WDT) | Yes, on-chip |
| Power-on Reset (POR) | Yes |
| Brown-out Reset (BOR) | No (not present on baseline PIC12C509) |
| ADC | None |
| Internal Oscillator | 4 MHz RC (factory calibrated) |
| External Oscillator | Not supported (RC only) |
| Operating Temperature | -40C to +85C (Industrial) |
| Package Type | 8-pin SOIJ (SM) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited floor life) |
| RoHS Status | Compliant |
PIC12C509T-04I/SM Pin Configuration
| Pin 1 | GP5/OSC1/CLKIN β Bidirectional I/O pin GP5; tied to internal oscillator |
| Pin 2 | GP4/OSC2 β Bidirectional I/O pin GP4; oscillator output |
| Pin 3 | GP3/MCLR/VPP β Input-only pin GP3; shared with Master Clear reset and programming voltage input |
| Pin 4 | GP2/T0CKI β Bidirectional I/O pin GP2; alternate TMR0 clock input |
| Pin 5 | GP1 β Bidirectional I/O pin GP1 |
| Pin 6 | GP0 β Bidirectional I/O pin GP0 |
| Pin 7 | GND β Ground reference |
| Pin 8 | VDD β Positive supply voltage (2.5 V to 5.5 V) |
Typical Applications
PIC12C509T-04I/SM is suitable for 6 applications: Consumer Appliance Control, Battery-Powered Sensor Modules, Automotive Interior Accessories, LED Lighting Drivers, Simple Motor Control, Replaceable Logic in Legacy Designs.
Consumer Appliance Control
The PIC12C509T-04I/SM is well suited to consumer appliance control, where its 1.5 KB OTP program memory, 6 I/O pins, and 2.5V-5.5V supply range cover typical small-motor, solenoid, and indicator-LED tasks. The internal 4 MHz RC oscillator eliminates external clock components, reducing BOM cost in toaster-oven timers, coffee-machine controllers, and similar 8-pin designs. Power-on Reset (POR) and Watchdog Timer (WDT) provide brown-out and firmware-fault recovery without external supervisor parts. The 200 ns instruction cycle is fast enough for sensor polling, debounce routines, and PWM-style LED dimming using software loops.
Recommended
Battery-Powered Sensor Modules
The PIC12C509T-04I/SM is a strong fit for battery-powered sensor modules such as PIR motion detectors, door/window contact sensors, and remote control units, where its 2.5V minimum supply allows direct operation from a single 3V lithium coin cell. Sleep current is dominated by the device's < 1 uA standby, enabling multi-year battery life. The 6 I/O pins can be routed to one analog input via the comparator trick, a digital output, and an external interrupt source. Industrial -40C to +85C temperature grade covers indoor-outdoor deployments without premium cost.
Recommended
Automotive Interior Accessories
Inside the cabin, the PIC12C509T-04I/SM is appropriate for low-speed accessories such as LED vanity-mirror controllers, ambient lighting drivers, and HVAC damper servo interfaces. Its industrial -40C to +85C range handles cabin-temperature extremes, and the 5.5V maximum supply tolerates load-dump-filtered 12V battery rails. The PIC core's deterministic 1 us instruction cycle simplifies timing analysis for CAN-bus-side interfaces and LIN-like UART software implementations. For under-hood applications, designers should select an AEC-Q100 qualified PIC instead, such as the PIC16F15313-I/SN.
Recommended
LED Lighting Drivers
The PIC12C509T-04I/SM drives single-channel or RGB LED strings in decorative and architectural lighting fixtures, where its 6 I/O pins can be assigned to three MOSFET gate drivers and one enable signal. Software-based PWM at frequencies up to 4 kHz avoids flicker in camera applications, while the PIC12C509A's 14-bit instructions provide headroom for color-mixing algorithms. The 2.5V-5.5V supply operates directly from a 5V regulated bus. Industrial temperature grade allows outdoor-enclosure deployment.
Recommended
Simple Motor Control
For small DC motor and unipolar stepper control in applications such as valve actuators, locks, and small pumps, the PIC12C509T-04I/SM's 6 I/O pins can drive two H-bridge halves and read one or two end-stop inputs. The internal 4 MHz RC oscillator is sufficient for software-step commutation rates up to a few kHz. Watchdog timer and POR provide fault recovery if firmware enters an unexpected state. The PIC12C509A upgrade is recommended when more sophisticated acceleration/deceleration profiles are needed.
Recommended
Replaceable Logic in Legacy Designs
The PIC12C509T-04I/SM is a popular drop-in replacement for legacy 8-pin glue-logic gates and small PALs in industrial control modules, where the OTP memory allows fixed-function firmware that exactly mimics discrete logic. The 2.5V-5.5V supply covers 3.3V and 5V legacy rails, and the industrial -40C to +85C range matches the original operating environment. The 33-instruction baseline PIC core is straightforward to program in assembly language for engineers maintaining installed-base equipment. For new designs, the flash-based PIC10F200 family is preferred for in-field updates.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509T-04I/SM β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509A-04I/SM | PIC12C509A-04/SM | PIC12C509-04E/SM | PIC12C509-04I/SM | PIC12C508A-04I/SM | PIC10F200T-I/OT |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-pin SOIJ (SM) | 8-pin SOIJ (SM) - same | 8-pin SOIJ (SM) - same | 8-pin SOIJ (SM) - same | 8-pin SOIJ (SM) - same | 8-pin SOIJ (SM) - same | 6-pin SOT-23 - different |
| Program Memory Size | 1.5 KB (1K x 12) OTP | 1.75 KB Flash/EPROM | 1.75 KB Flash/EPROM | 1.5 KB (1K x 12) OTP | 1.5 KB (1K x 12) OTP | 0.75 KB (768 x 12) | 256 words Flash |
| RAM | 41 bytes | 80 bytes | 80 bytes | 41 bytes | 41 bytes | 25 bytes | 16 bytes |
| Maximum CPU Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Instruction Set Width | 12-bit | 14-bit | 14-bit | 12-bit | 12-bit | 12-bit (508) / 14-bit (508A) | 12-bit |
| Operating Temperature Range | -40C to +85C (Industrial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| I/O Pins | 6 | 6 | 6 | 6 | 6 | 6 | 4 |
| Watchdog Timer | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Approximate Qty-1 Price (USD) | $1.42 | $1.55 | $1.40 | $1.50 | $1.40 | $1.30 | $0.65 |
Key Differentiators
- 8-pin SOIJ industrial-temperature MCU at the lowest cost in the PIC baseline family (vs PIC12C508A-04I/SM)
- Industrial -40C to +85C temperature grade standard vs commercial-only on -04 variants (vs PIC12C509A-04/SM)
- Internal 4 MHz oscillator eliminates external clock components (vs PIC12C509A-04I/SM)
Design Notes
The PIC12C509T-04I/SM operates from 2.5V to 5.5V. Place a 0.1 uF decoupling capacitor as close as possible to the VDD pin (pin 8) and a bulk 10 uF capacitor on the supply rail. For battery-powered designs below 3.0V, verify the internal POR trip point - the datasheet specifies a guaranteed POR threshold around 2.0V-2.3V, but staying above 2.5V prevents brown-out lockups in cold temperatures. Estimated: VDD quiescent current is typically 1-2 mA at 4 MHz with all peripherals active, dropping to a few microamps in sleep mode.
In the 8-pin SOIJ package, pin 1 is identified by the chamfered corner or notch mark on the package top. The SOIJ footprint is smaller than SOIC-8 - confirm pad dimensions against the Microchip SOIJ-8 land pattern recommendation in the package specification document. Keep traces to GP3/MCLR short to minimize the risk of inadvertent resets from capacitive coupling. The exposed lead frame on the bottom of the SOIJ package is NOT designed for thermal dissipation, so no copper pour connection is required.
Three common pitfalls when using the PIC12C509T-04I/SM: (1) GP3 is input-only - attempting to drive it as an output will not work and may damage the part on some lots. (2) The OTP program memory can be programmed only once - any code bug requires a new part, not a reprogramming. (3) The internal 4 MHz RC oscillator has a +/- 2% accuracy over the full -40C to +85C range, so UART-style bit-banged communication at high baud rates may need calibration. Use the PIC12C509A-04I/SM with crystal oscillator support for timing-sensitive applications.
For in-circuit serial programming (ICSP), expose the GP3/MCLR/VPP pin (pin 3) and the VDD/GND pins to test points or a programming header. The ICSP interface uses GP0 as data and GP1 as clock. Keep the GP0 and GP1 traces short and avoid series resistors in the programming path - the ICD programmer drives these lines directly. If the design uses GP0/GP1 for high-current outputs, add 0-ohm series jumpers that can be removed during programming.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified - the -04I industrial temperature grade is specified for -40C to +85C only. For AEC-Q100 automotive applications, use PIC16F15313 or other qualified PIC microcontrollers.
