PIC12C509AT-04E/SN - 8-Bit OTP MCU 1.5KB 4MHz SOIC8 | Microchip
MPN: PIC12C509AT-04E/SN ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.1 | $2.10 |
| 10 | $1.95 | $19.50 |
| 100 | $1.72 | $172.00 |
| 500 | $1.48 | $740.00 |
| 1,000 | $1.25 | $1,250.00 |
PIC12C509AT-04E/SN Overview
An OTP (One-Time Programmable) microcontroller is a type of non-volatile MCU where the program memory can be written exactly once using a programmer device, after which it becomes read-only. Unlike Flash-based MCUs, OTP devices cannot be erased or reprogrammed in-circuit, making them well suited for cost-sensitive, high-volume consumer and industrial applications where the firmware is fixed at production time. The PIC12C509A belongs to the broader hierarchy of 8-bit microcontrollers -> RISC microcontrollers -> embedded MCUs -> integrated circuits, and uses Microchip's PIC RISC architecture, which executes instructions in a single instruction cycle.
Key features include 33 single-word instructions, 1 us instruction execution time at 4 MHz, an 8-bit timer/counter, internal 4 MHz RC oscillator (with external clock option), and wide operating voltage range of 2.5V to 5.5V. The device also has a programmable code protection bit, a watchdog timer with on-chip RC oscillator (independent of external clock), and 6 general-purpose I/O pins capable of source/sink up to 25 mA per pin for direct LED drive. The extended temperature grade (-40C to +125C) enables deployment in harsh industrial and automotive under-hood environments.
The PIC12C509AT-04E/SN uses a 12-bit instruction word and a Harvard-architecture RISC core with separate instruction and data buses, which lets the CPU fetch an instruction and access data in the same cycle. Compared to older CISC 8-bit MCUs, this architecture delivers roughly 4x the throughput per MHz, allowing the 4 MHz oscillator to deliver the equivalent of a 16 MHz CISC controller. This is critical for battery-powered applications where the MCU clock and CPU activity directly determine average current draw.
Typical applications include low-cost consumer appliances, automotive body controllers (lighting, key fobs, sensors), smart sensors, battery chargers, small motor controls, IR remote-control receivers, and standalone timing/logic replacement. The SOIC-8 package and standard programming interface make it an excellent drop-in upgrade for older 8-pin PIC12C508 designs that need additional program memory.
When designing with the PIC12C509AT-04E/SN, ensure you use a proper in-circuit serial programming (ICSP) header for the one-time programming step, since OTP memory cannot be re-programmed in-circuit. Decoupling capacitors (100 nF ceramic plus 10 uF bulk) should be placed within 5 mm of the VDD pin to maintain supply integrity during high-current I/O transitions. This page synthesizes distributor stock, drop-in same-package alternatives from the PIC12C family, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC12C509AT-04E/SN — 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 PIC12C509AT-04E/SN (same form factor and footprint) — differing in Package, Timers, Core Architecture, I/O Pins, Watchdog Timer.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12C509AT-04/SN
✅ Drop-In✓ In Stock
$1.02 / Unit
View Datasheet →PIC12C509A-04E/SN
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C509A-04/SN
✅ Drop-In✓ In Stock
$0.98 / Unit
View Datasheet →PIC12C509A-04I/SN
✅ Drop-In✓ In Stock
$0.92 / Unit
View Datasheet →PIC12F519-I/SN
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C509AT-04E/SN Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Core Architecture | PIC RISC (Harvard) |
| Program Memory Size | 1.5 KB (1K x 12), OTP |
| RAM Size | 41 bytes |
| Data EEPROM | None (OTP only) |
| Maximum CPU Frequency | 4 MHz |
| Instruction Set | 33 single-word instructions, 12-bit opcode |
| Instruction Execution Time | 1 us at 4 MHz |
| I/O Pins | 6 GPIO |
| Timers | 1 x 8-bit timer/counter |
| Operating Voltage Range | 2.5 V to 5.5 V |
| Operating Temperature Range | -40 C to +125 C (Extended) |
| Package | 8-SOIC (0.154 inch / 3.90 mm body width) |
| Pin Count | 8 |
| Mounting Type | Surface Mount |
| I/O Sink/Source Current | 25 mA per pin (max) |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| Programming Method | ICSP (In-Circuit Serial Programming) |
| Code Protection | Programmable code-protect bit |
| RoHS Status | Compliant |
| MSL Level | 1 (unlimited floor life) |
PIC12C509AT-04E/SN Pin Configuration
| Pin 1 | GP5/OSO/CLKIN — Bidirectional I/O pin; serial programming clock (ICSPCLK) for ICSP |
| Pin 2 | GP0/GP — Bidirectional I/O; also GP0 |
| Pin 3 | GP1/GP — Bidirectional I/O; also GP1 |
| Pin 4 | GP2/GP/T0CKI — Bidirectional I/O; T0CKI timer0 clock input; serial programming data (ICSPDAT) |
| Pin 5 | GP3/MCLR/VPP — Input only; Master Clear reset or programming voltage input |
| Pin 6 | GP4/OSC2 — Bidirectional I/O; oscillator output (XTAL/RC mode) |
| Pin 7 | GP5/OSC1/CLKIN — Bidirectional I/O; oscillator input / external clock input |
| Pin 8 | VDD — Positive supply voltage (2.5 V to 5.5 V) |
Typical Applications
PIC12C509AT-04E/SN is suitable for 6 applications: Automotive Body and Lighting Controllers, Low-Cost Consumer Appliance Control, Infrared Remote-Control Receiver, Battery Charger and Smart Battery Management, Smart Sensor and Sensor-Hub Node, Logic Replacement and Glue Logic Consolidation.
Automotive Body and Lighting Controllers
The PIC12C509AT-04E/SN fits automotive body and lighting controllers because of its extended -40C to +125C temperature grade, 6 GPIO capable of 25 mA source/sink (enough to drive small relays and MOSFET gates directly), and 1.5 KB of OTP program memory sufficient for sequential lighting or indicator logic. The RISC core delivers 1 MIPS at 4 MHz, which is fast enough for PWM-based LED dimming or simple CAN/LIN-stand-in logic when paired with an external transceiver. Its 8-pin SOIC footprint drops onto existing body-controller PCB land patterns used in door modules, seat controllers, and ambient-lighting drivers. The watchdog timer with dedicated RC oscillator provides an autonomous fail-safe against clock-source glitches, meeting typical automotive reliability requirements. Compared to a discrete logic replacement, the PIC12C509AT-04E/SN consolidates 30+ logic gates into a single $1 IC.
Recommended
Low-Cost Consumer Appliance Control
The PIC12C509AT-04E/SN is a strong fit for cost-sensitive consumer appliance control boards (toaster ovens, coffee makers, hair dryers, fans) where the firmware is fixed at production time. The 1.5 KB OTP program memory accommodates simple state machines for thermistor readout, push-button input, and relay/SSR drive. Its 2.5V-5.5V operating range lets the same part serve 3.3V logic and 5V relay-driver designs. With 6 GPIO sourcing 25 mA, the MCU can directly switch indicator LEDs and low-side MOSFETs without buffer transistors, shrinking the BOM. The 8-SOIC package is hand-solderable for prototyping yet small enough for high-density control boards. Watchdog + code-protect bits add a layer of IP protection against cloning for branded appliances.
Recommended
Infrared Remote-Control Receiver
The PIC12C509AT-04E/SN fits IR remote-control receiver firmware decoders that translate NEC, RC-5, or Sony SIRC IR-modulated signals into appliance commands. The 4 MHz core and 1 us instruction cycle allow bit-level decoding of 38 kHz / 40 kHz / 56 kHz carrier demodulation in firmware using a single GPIO + interrupt on change. The 1.5 KB program memory holds a full RC-5/RC-6 lookup table plus a state machine for repeat-code suppression. Its 8-pin SOIC footprint is small enough to mount behind the appliance's IR receiver window. The watchdog timer guards against firmware hang in the decoder loop, recovering via a reset. For battery-powered remote transmitters, the PIC10F200T-E/OT in a 6-pin SOT-23 is the natural pair on the transmit side.
Recommended
Battery Charger and Smart Battery Management
The PIC12C509AT-04E/SN is well suited for low-power smart battery chargers for 2-4 cell NiMH/Li-ion packs, where the OTP memory stores charging profiles (CC/CV thresholds, timer values, temperature cutoffs). The internal 4 MHz RC oscillator keeps BOM cost down versus a crystal, and the wide 2.5V-5.5V VDD range operates directly from a single Li-ion cell or USB 5V rail. The 8-bit timer combined with software state-machine code can implement coulomb-counting, delta-V termination, and safety timer shutdown without external ASICs. Its extended temperature grade supports chargers that sit near the battery pack in high-heat environments (e.g., e-bike chargers). The 6 GPIO easily handle status LEDs, enable switches, and current-sense comparator reads.
Recommended
Smart Sensor and Sensor-Hub Node
The PIC12C509AT-04E/SN functions as a minimal sensor-hub MCU for thermistor, photodiode, hall-effect, or PIR motion sensor interfaces that need to produce a digital alarm/control output. The 6 GPIO accept multiple digital sensors directly and drive an LED/buzzer indicator; if an analog sensor is used, the MCU can implement a software sigma-delta ADC using one GPIO and two passives. Its 1.5 KB program memory is enough to store calibration constants in OTP and run a linearization algorithm. The extended temperature range and small 8-SOIC package fit outdoor weather-station or industrial sensor modules. For higher-accuracy analog sensor hubs the PIC12F519-I/SN (with built-in 10-bit ADC) is the natural upgrade.
Recommended
Logic Replacement and Glue Logic Consolidation
The PIC12C509AT-04E/SN replaces dozens of discrete logic gates (7400-series TTL/CMOS) in designs where a small state machine would otherwise consume 5-10 ICs. With 33 single-word instructions and 1 us execution, the PIC12C509AT-04E/SN can implement custom decoder, multiplexer, latch, and pulse-generator functions in a single 8-pin SOIC. The 25 mA per-pin drive eliminates buffer-driver ICs for LED, relay coil, or small solenoid drive. Compared to a discrete logic replacement, the OTP MCU costs less than 5 quad-gate ICs and dramatically shrinks PCB area. Industrial designers use this approach to add features (timing, sequencing, code-protect IP) without a board respin.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C509AT-04E/SN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C509AT-04/SN | PIC12C509A-04E/SN | PIC12C509A-04/SN | PIC12C509A-04I/SN | PIC12F519-I/SN |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-SOIC (SN, 3.90 mm) | 8-SOIC (SN, 3.90 mm) - same | 8-SOIC (SN, 3.90 mm) - same | 8-SOIC (SN, 3.90 mm) - same | 8-SOIC (SN, 3.90 mm) - same | 8-SOIC (SN, 3.90 mm) - same |
| Program Memory Type | OTP (1.5 KB) | OTP (1.5 KB) - same | OTP (1.5 KB) - same | OTP (1.5 KB) - same | OTP (1.5 KB) - same | Flash (1.5 KB) - different |
| Maximum CPU Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 8 MHz (faster) |
| RAM | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes | 41 bytes |
| Operating Voltage | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.0 V to 5.5 V |
| Operating Temperature | -40 C to +125 C (Extended) | 0 C to +70 C (Commercial) | -40 C to +125 C (Extended) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
| I/O Pins | 6 | 6 | 6 | 6 | 6 | 6 |
| On-chip ADC | None | None | None | None | None | 10-bit ADC (added) |
Key Differentiators
- Extended temperature grade covers automotive and industrial ranges (vs PIC12C509AT-04/SN (Commercial 0C to +70C))
- Pin-compatible Flash upgrade path without PCB redesign (vs PIC12F519-I/SN (Flash, 8 MHz))
- Same 8-SOIC footprint as commercial sibling for source-of-supply diversification (vs PIC12C509A-04I/SN (Industrial -40C to +85C))
- 25 mA per-pin GPIO drive eliminates external buffers (vs PIC12F519-I/SN (Flash variant))
Design Notes
Estimated: VDD rail decoupling - place a 100 nF X7R ceramic capacitor within 5 mm of the VDD pin and a 10 uF X5R bulk capacitor on the same rail. The 6 GPIO toggling at 25 mA each can induce up to 150 mA of supply transients during simultaneous switching, so bulk capacitance prevents VDD sag from causing a brown-out reset. A 100 mV ripple budget is realistic for the 2.5V-5.5V input range. For battery applications, the PIC12C509AT-04E/SN draws roughly 1 mA active at 4 MHz / 5V and < 1 uA in SLEEP mode.
OTP programming requires ICSP - the PIC12C509AT-04E/SN's program memory is One-Time Programmable, meaning it cannot be erased in-circuit. Use an ICSP header (RB6/ICSPCLK and RB7/ICSPDAT) on the prototype board to allow programming before final assembly. Once programmed, attempting to re-program the OTP part will not work - use a PIC12F519-I/SN prototype for development and switch to OTP only for production. Watchdog timer is on a dedicated internal RC oscillator, so it remains active even if the main oscillator fails.
Place the ICSP header (5-pin: VPP, VDD, VSS, ICSPCLK, ICSPDAT) on a 0.1 inch-pitch connector at the board edge for programming access. Route the GP3/MCLR/VPP pin to a pull-up resistor (typically 10 kohm) and the ICSP connector with separate traces to avoid noise coupling. GP4/OSC2 and GP5/OSC1/CLKIN are the oscillator pins; keep crystal traces short (under 5 mm) and guard them with a ground pour if a crystal is used. For RC oscillator mode, place the timing resistor and capacitor close to GP5/OSC1 with the other end of the resistor to VDD.
Keep the VDD trace width at least 0.5 mm to handle the 150 mA peak GPIO current, and use a ground pour on the opposite layer to provide a low-impedance return path. Avoid routing high-frequency signals (PWM, oscillator) under the IC body to minimize coupling into the substrate. The exposed copper under the SOIC should be tied to ground for thermal spreading - at 4 MHz the device dissipates under 50 mW, so a small copper pour is adequate.
Compliance Information
RoHS compliant per Microchip product page and distributor listings (Mouser, DigiKey). AEC-Q100 qualification status not published; AEC-Q100-grade automotive customers typically use the PIC12C509A-04E/SN under automotive PPAP or contact Microchip for Q-graded variants. Halogen-free status not explicitly published.
