PIC12C508AT-04I/SN - 8-bit OTP MCU, 768B, 4MHz, 8-SOIC | Microchip
MPN: PIC12C508AT-04I/SN ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.1 | $2.10 |
| 10 | $1.95 | $19.50 |
| 100 | $1.75 | $175.00 |
| 500 | $1.55 | $775.00 |
| 1,000 | $1.4 | $1,400.00 |
PIC12C508AT-04I/SN Overview
A PIC12C5xx-class microcontroller belongs to the 8-bit microcontroller family, which in turn sits within the broader category of microcontrollers (MCUs) and embedded controllers in semiconductor systems. These 8-bit MCUs are widely used in cost-sensitive, low-pin-count applications because they combine a compact footprint with deterministic RISC execution and a small, easy-to-learn instruction set. The PIC12C5xx uses only 33 single-word instructions and provides 2:1 code compression over typical 8-bit CISC competitors, allowing small OTP programs to deliver meaningful control functionality.
Key features of the PIC12C508AT-04I/SN include the 4 MHz internal/external oscillator option, six general-purpose digital I/O pins, a power-on reset (POR) circuit, a watchdog timer (WDT) with on-chip RC oscillator, a programmable code protection mechanism, and an in-circuit serial programming (ICSP) interface. The device offers low power consumption with typical sleep current in the microamp range and supports operating voltages from 3.0V to 5.5V. The 12-bit wide instruction word and Harvard architecture allow single-cycle instruction fetch and execution.
Architecturally, the PIC12C508A combines a RISC engine with separate program and data buses (Harvard architecture), enabling simultaneous instruction fetch and data access. The OTP program memory uses 12-bit-wide words, providing efficient encoding for the 33-instruction RISC set. On-chip peripherals include an 8-bit real-time timer/counter (TMR0), a watchdog timer with its own dedicated RC oscillator, and a power-on reset generator, eliminating many external components and reducing BOM cost.
Typical applications include appliance control, automotive body electronics (after market), industrial control, intelligent instrumentation, remote transmitters, security systems, and small consumer products such as LED drivers, fan controllers, and battery chargers. The 8-pin footprint makes it suitable for space-constrained PCB designs where simple, deterministic logic replacement is required.
When designing with this part, note that OTP memory is one-time programmable, so code must be fully verified before production programming. Decoupling capacitors (typically 0.1 uF ceramic) should be placed close to VDD, and unused I/O pins should be configured as outputs to minimize power consumption. For new designs, evaluate the PIC10F200/PIC10F202 or PIC12F508 flash-based equivalents, which support in-circuit reprogramming and may reduce development time.
This page synthesizes distributor pricing, drop-in OTP and flash-replacement alternatives, and practical design notes not found in the manufacturer datasheet alone. Engineers can use the comparison table and design notes below to evaluate the PIC12C508AT-04I/SN against modern flash alternatives.
Drop-in alternatives for PIC12C508AT-04I/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 PIC12C508AT-04I/SN (same form factor and footprint) — differing in Package, Program Memory Size, RAM Size, Instruction Execution Time, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12C508A-04I/SN
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C508AT-04E/SN
✅ Drop-In✓ In Stock
$0.85 / Unit
View Datasheet →PIC12C508A-04I/SM
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC12F508-I/SN
✅ Drop-In✓ In Stock
$0.31 / Unit
View Datasheet →PIC12C508AT-04I/SN Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-Bit |
| Maximum Clock Frequency | 4 MHz |
| Instruction Execution Time | 1 us (4 MHz / 4) |
| Program Memory Size | 768 B (512 x 12) |
| Program Memory Type | OTP (One-Time Programmable) |
| RAM Size | 25 B |
| Number of I/O Pins | 6 |
| Supply Voltage (VDD) | 3.0 V to 5.5 V |
| Operating Temperature | -40 C to +85 C (Industrial, "I") |
| Package | 8-SOIC (SN), 3.90 mm body, surface mount |
| Mounting Type | Surface Mount |
| Oscillator Type | External / Internal RC |
| Number of Instructions | 33 single-word |
| Watchdog Timer (WDT) | Yes, dedicated on-chip RC |
| In-Circuit Serial Programming (ICSP) | Yes |
| Code Protection | Programmable |
| RoHS Status | Compliant (per distributor listings) |
| Packaging | Tape & Reel ("T" suffix) |
PIC12C508AT-04I/SN Pin Configuration
| Pin 1 | GP5/OSO/CLKOUT — Bidirectional I/O / oscillator output / clockout |
| Pin 2 | GP4/OSC1/CLKIN — Bidirectional I/O / oscillator input / external clock input |
| Pin 3 | GP3/MCLR/VPP — Bidirectional I/O / Master Clear (reset) / programming voltage |
| Pin 4 | GP2/T0CKI/INT — Bidirectional I/O / Timer0 clock input / external interrupt |
| Pin 5 | GP1/CIN-/ICSPCLK — Bidirectional I/O / comparator inverting input / ICSP clock |
| Pin 6 | GP0/CIN+/ICSPDAT — Bidirectional I/O / comparator non-inverting input / ICSP data |
| Pin 7 | VSS — Ground reference |
| Pin 8 | VDD — Positive supply voltage (3.0 V to 5.5 V) |
Typical Applications
PIC12C508AT-04I/SN is suitable for 6 applications: Appliance Control Boards, Automotive Body Electronics, Remote Control Transmitters, Industrial Sensor Signal Conditioning, LED Lighting Controllers, Smart Battery Chargers.
Appliance Control Boards
The PIC12C508AT-04I/SN is well-suited for low-cost appliance controls such as coffee makers, toasters, microwave ovens, and washing machine user interfaces. Its 8-pin SOIC footprint and 6 GPIO pins are sufficient for keypad scanning, LED driving, and triac-trigger control signals, while the 768-byte OTP program memory holds typical appliance state-machine firmware. The 4 MHz core provides 1 microsecond instruction execution, adequate for debounce, timing, and relay sequencing. Compared to a discrete logic implementation, the PIC12C508A integrates timer/counter, watchdog, and POR, reducing BOM cost and PCB area - critical for high-volume appliance production.
Recommended
Automotive Body Electronics
The PIC12C508AT-04I/SN with industrial -40C to +85C temperature grade handles automotive aftermarket body electronics such as alarm systems, remote keyless entry receivers, and lighting controllers. The wide 3.0V-5.5V supply range tolerates vehicle battery fluctuations including cold-crank and load-dump conditions when paired with appropriate protection. Six GPIO pins support relay driving and switch inputs, while the on-chip watchdog timer prevents lockup in unattended modules. The OTP memory locks firmware after production programming, preventing tampering - a valuable property in security applications where code confidentiality matters.
Recommended
Remote Control Transmitters
Battery-powered RF remote controls benefit from the PIC12C508AT-04I/SN's low sleep current, small 8-SOIC package, and 6 GPIO pins for button matrix scanning and RF module control. The 4 MHz internal RC oscillator eliminates external crystal cost, and the OTP memory provides one-time firmware lock-in for consumer products. With 25 bytes of RAM and 768 bytes of program space, the PIC12C508A handles simple button-debounce, rolling-code generation, and low-battery detection algorithms typical in remote controls. The -40C to +85C industrial temperature range covers both indoor and outdoor operating environments.
Recommended
Industrial Sensor Signal Conditioning
The PIC12C508AT-04I/SN fits small industrial sensor interface modules requiring microcontroller intelligence without the cost of larger MCUs. Its on-chip 8-bit timer/counter (TMR0) handles pulse counting from flow meters or proximity sensors, while six GPIO pins interface to analog sensors via external op-amps and comparators. The 4 MHz instruction rate provides sufficient throughput for 10 ms-class control loops. The 3.0V-5.5V supply range accommodates industrial 24V-bus powered designs after regulator stepping, and the -40C to +85C industrial temperature grade handles factory floor conditions. OTP programming locks calibration values per sensor module at production.
Recommended
LED Lighting Controllers
Small LED lighting products including decorative strings, status indicators, and architectural accent lights use the PIC12C508AT-04I/SN for PWM dimming and pattern generation. Six GPIO pins can drive multiple LED channels directly with current-limiting resistors, or control higher-power LEDs through external MOSFETs. The 4 MHz core generates PWM frequencies suitable for LED dimming without flicker, and 768 bytes of OTP holds pattern tables for chasing or breathing effects. The 8-pin SOIC package fits inside lamp bases and inline controllers, while OTP programming locks the lighting sequence to prevent unauthorized modification.
Recommended
Smart Battery Chargers
Single-cell or small multi-cell battery chargers use the PIC12C508AT-04I/SN for voltage/current monitoring and charge termination control. Six GPIO pins support voltage divider sensing, current shunt amplification input, and charge MOSFET gating. The 4 MHz execution rate handles CC-CV algorithm steps at appropriate sampling rates. The 3.0V-5.5V VDD range lets the MCU share the battery rail directly in single-cell Li-ion applications. Industrial -40C to +85C temperature grade covers charger thermal environments, while OTP memory locks the charging algorithm to a specific chemistry preventing user misconfiguration.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C508AT-04I/SN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C508A-04I/SN | PIC12C508AT-04E/SN | PIC12C508A-04I/SM | PIC12F508-I/SN |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-SOIC (SN) | 8-SOIC (SN) | 8-SOIC (SN) | 8-SOIJ (SM) | 8-SOIC (SN) |
| Program Memory Type | OTP (768 B) | OTP (768 B) | OTP (768 B) | OTP (768 B) | Flash (768 B) |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Operating Temperature | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | 0 C to +70 C (Extended) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
| RAM Size | 25 B | 25 B | 25 B | 25 B | 25 B |
| Number of I/O Pins | 6 | 6 | 6 | 6 | 6 |
| Packaging Format | Tape & Reel ("T") | Tube | Tape & Reel | Tape & Reel (SOIJ) | Tube or Tape & Reel |
| In-Circuit Reprogramming | No (OTP) | No (OTP) | No (OTP) | No (OTP) | Yes (Flash) |
| Lifecycle Status | Last-time-buy | Last-time-buy | Active | Last-time-buy | Active |
Key Differentiators
- Industrial temperature grade for harsh environments (vs PIC12C508AT-04E/SN)
- Flash reprogrammability for development flexibility (vs PIC12F508-I/SN)
- Compact 8-SOIC package with 6 GPIO in smallest Microchip PIC footprint (vs PIC12C508A-04I/SM (8-SOIJ))
Design Notes
OTP memory cannot be erased or rewritten - all firmware bugs must be debugged and fixed in code before programming the production lot. For prototypes, use a flash-based equivalent such as PIC12F508-I/SN in the same 8-SOIC footprint, then port the verified firmware to the PIC12C508AT for production. Developers should also budget for programming-tooling cost (Microchip PICkit or equivalent) since OTP parts require device programmers, not ICSP debug probes.
Place a 0.1 uF ceramic decoupling capacitor as close as possible to the VDD pin (pin 8) and VSS pin (pin 7) on the PIC12C508AT-04I/SN. For designs operating across 3.0V-5.5V with high GPIO switching transients, a bulk 10 uF tantalum or aluminum capacitor is recommended near the supply rail. Decoupling prevents supply droops that can trigger spurious brown-out or MCLR resets, especially during AC load triac firing in appliance control applications.
Configure all unused GPIO pins on the PIC12C508AT-04I/SN as outputs (set TRISIO bits to 0) to minimize sleep current and prevent floating-input-induced oscillation. Per the Microchip PIC12C5XX datasheet (DS40139E), floating inputs can draw additional supply current and may cause unintended wake-ups from sleep. For SOIC-8 layouts, maintain at least 0.2 inch clearance around the part for probe-tip access during initial bring-up and oscilloscope debugging.
When using the internal RC oscillator on PIC12C508AT-04I/SN, the GP4/OSC1 and GP5/OSO pins can be repurposed as standard GPIO. If an external crystal or resonator is used, place it within 0.5 inch of pins 1-2 and route the OSC traces over a continuous ground plane to minimize EMI pickup. The MCLR pin (pin 3) should have a pull-up resistor (typically 10 kohm) to VDD and a 100 nF capacitor to ground for reset noise immunity, unless external reset is intentionally driven by a supervisor IC.
Compliance Information
RoHS and lead-free compliance per Microchip product page and DigiKey/Mouser distributor listings. AEC-Q100 not qualified - automotive use cases are aftermarket/low-tier body electronics. Lifecycle approaching end-of-life - consider PIC12F508-I/SN flash equivalent for new designs.
