PIC12C508A-04I/SM - 8-bit 4MHz OTP MCU, 8-SOIJ | Microchip
MPN: PIC12C508A-04I/SM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.62 | $16.20 |
| 100 | $1.38 | $138.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $1.05 | $1,050.00 |
PIC12C508A-04I/SM Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, program and data memory, and I/O peripherals. MCUs sit within the broader taxonomy of embedded processors -> microcontrollers -> 8-bit microcontrollers -> CMOS RISC microcontrollers. The 12-bit program word width and Harvard bus architecture of the PIC12 family are deliberately simple, enabling deterministic timing and very small silicon footprints for cost-sensitive embedded applications.
Key features include 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, Power-On Reset (POR), Device Reset Timer (DRT), and programmable code protection. The internal 4 MHz oscillator eliminates external timing components, freeing all eight pins for application use. The SOIJ-8 footprint allows direct reflow soldering on standard SMT lines.
The architecture separates program memory (12-bit OTP) from data memory (8-bit-wide registers), enabling single-cycle instruction fetch and decode. The reduced 33-instruction RISC instruction set simplifies code generation, while the 200 ns minimum instruction cycle at 4 MHz (when derived from the internal RC oscillator divided appropriately) provides ample throughput for glue-logic replacement, sequencer, and protocol-translation tasks.
Typical applications include low-cost consumer appliance control, sensor-interface front-ends, automotive interior accessories, industrial timing and sequencing, and PIC12C508 pin-compatible upgrades. The wide operating voltage window supports both 3.3 V and 5 V rails commonly found in mixed-signal systems, allowing the part to coexist with low-power sensors and 5 V relay drivers.
When designing with this device, pay attention to OTP one-time programmability — once blown, code cannot be changed. For prototyping or field-upgradable designs, choose the Flash-based PIC12F508 successor (same pinout, larger memory, in-circuit serial programming). Decoupling the VDD pin with a 0.1 µF ceramic capacitor adjacent to the package is recommended for stable internal RC operation.
This page synthesizes distributor pricing, pin-compatible same-family alternatives, and practical design notes not aggregated on the manufacturer datasheet, enabling faster sourcing decisions for engineers migrating legacy PIC12C508A designs to current production.
Drop-in alternatives for PIC12C508A-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 PIC12C508A-04I/SM (same form factor and footprint) — differing in Core Architecture, Program Memory Size, Instruction Execution Time, Timers, Data EEPROM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12C508A-04/SM
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12C509A-04I/SM
✅ Drop-In✓ In Stock
$0.93 / Unit
View Datasheet →PIC12C509A-04/SM
✅ Drop-In✓ In Stock
$0.99 / Unit
View Datasheet →PIC12F508-I/SM
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12CE518-04I/SM
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12C508A-04E/SM
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12C508A-04I/SM Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 768 B (512 x 12) |
| RAM Size | 25 x 8 bytes |
| EEPROM Size | None |
| CPU Speed | 4 MHz |
| Instruction Set | 33 single-word/single-cycle instructions |
| Instruction Execution Time | 1 µs (at 4 MHz) |
| Supply Voltage (Vdd) | 3 V to 5.5 V |
| I/O Pins | 6 |
| Timers | TMR0 with 8-bit programmable prescaler, WDT |
| Oscillator Type | Internal RC |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| Package | 8-SOIJ (8-pin Small Outline IC, J-leaded) |
| Data Converters | None |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Reset/POR | Power-On Reset (POR), Device Reset Timer (DRT) |
| Code Protection | Programmable |
PIC12C508A-04I/SM Pin Configuration
| Pin 1 | GP5/OSC1/CLKIN — General-purpose I/O / oscillator input / external clock input |
| Pin 2 | GP4/OSC2/CLKOUT — General-purpose I/O / oscillator output / clock output |
| Pin 3 | GP3/MCLR/Vpp — General-purpose I/O / Master Clear Reset / programming voltage input |
| Pin 4 | Vss — Ground reference |
| Pin 5 | GP0/T0CKI — General-purpose I/O / Timer0 clock input |
| Pin 6 | GP1/AN1 — General-purpose I/O / analog comparator input |
| Pin 7 | GP2/AN0/T0CKI — General-purpose I/O / analog comparator input / Timer0 clock input |
| Pin 8 | Vdd — Positive supply voltage, 3 V to 5.5 V |
Typical Applications
PIC12C508A-04I/SM is suitable for 6 applications: Low-Cost Consumer Appliance Control, Sensor Interface Front-End, Automotive Interior Accessories, Industrial Timing and Sequencing, PIC12C508A Pin-Compatible Upgrade Path, Protocol Translation Bridge.
Low-Cost Consumer Appliance Control
The PIC12C508A-04I/SM is well suited for low-cost consumer appliance controllers where firmware is finalized at production and cost-per-node is the dominant constraint. Its 768 bytes of OTP program memory can host sequencing logic for rice cookers, coffee makers, small fans, and personal-care devices, while the 33-instruction RISC core delivers deterministic 1 µs instruction execution at 4 MHz for tight timing loops. The 6 available I/O pins drive LEDs, triac-trigger optocouplers, and keypads directly, and the internal 4 MHz RC oscillator eliminates two external timing components compared to PIC16F alternatives. At roughly $1.05 USD per unit at 1k quantity, the part enables sub-$3 BOM for high-volume household SKUs.
Recommended
Sensor Interface Front-End
As a sensor-interface front-end, the PIC12C508A-04I/SM converts analog sensor signals into digital outputs by leveraging its 6 I/O pins for multiplexed ADC triggering, calibration routines, and threshold-based decisions. Although the chip itself lacks an on-chip ADC, external delta-sigma or SAR converters connect directly via the GPIO pins, and the 4 MHz CPU runs linearization math at sub-millisecond latency. The 3 V to 5.5 V supply window lets the same board accept 3.3 V digital sensors and 5 V analog front-ends without level shifters. The industrial -40 °C to +85 °C range supports outdoor HVAC and refrigeration deployments.
Recommended
Automotive Interior Accessories
The PIC12C508A-04I/SM runs interior accessory controllers such as dome-light timers, seat-heat indicators, and simple body-control modules where firmware does not require in-field updates. Its 4 MHz internal RC oscillator survives automotive cranking voltage transients, and the 33-instruction RISC set simplifies MISRA-style static analysis for safety-critical firmware. The 6 I/O pins drive low-side MOSFETs and read Hall-effect switches for door-ajar and seat-buckle feedback. The PIC12C508A-04I/SM is pin-compatible with the automotive-grade PIC12C508A-I/SN temperature variants, simplifying PCB reuse across consumer and automotive SKUs.
Recommended
Industrial Timing and Sequencing
For industrial timing and sequencing, the PIC12C508A-04I/SM delivers deterministic 1 µs per instruction, 8-bit TMR0 with 8-bit prescaler, and a Watchdog Timer with its own internal RC oscillator — all required for safety-critical sequencers in conveyor systems, packaging machines, and pump controllers. The industrial -40 °C to +85 °C temperature range handles unheated cabinet installations, and the 8-SOIJ package stands up to vibration better than DIP-8 alternatives. The 25-byte RAM is ample for state machines with up to eight timed steps, while the 768-byte OTP holds lookup tables for timing profiles.
Recommended
PIC12C508A Pin-Compatible Upgrade Path
Designers transitioning legacy PIC12C508A socket boards can drop in the PIC12C508A-04I/SM with no firmware or PCB changes, gaining the industrial -40 °C to +85 °C temperature grade and the SOIJ-8 surface-mount footprint in a single step. The same instruction set and 12-bit program word width let existing assembly code recompile unchanged, and the 768-byte OTP matches legacy code densities. For volume production, Microchip's long-term supply commitment to the PIC12C5XX family means the PIC12C508A-04I/SM is a safe drop-in for next-generation builds targeting 7+ year product lifecycles.
Recommended
Protocol Translation Bridge
The PIC12C508A-04I/SM acts as a low-cost protocol-translation bridge between simple peripheral devices and upstream controllers, mapping GPIO bit-banged UART, I2C, or one-wire transactions to a master MCU. Its 4 MHz CPU supports 9600-baud UART at the maximum instruction throughput, while 25 bytes of RAM buffer short message frames for forwarding. The internal RC oscillator removes crystal dependencies, reducing board area for cable-side dongles and adapters. The 3 V to 5.5 V supply window lets the same firmware run on either USB-powered 3.3 V dongles or 5 V industrial nodes.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C508A-04I/SM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C508A-04/SM | PIC12C509A-04I/SM | PIC12C509A-04/SM | PIC12F508-I/SM | PIC12CE518-04I/SM |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-SOIJ | 8-SOIJ | 8-SOIJ | 8-SOIJ | 8-SOIJ | 8-SOIJ |
| Program Memory Type | OTP | OTP | OTP | OTP | Flash (ICSP) | OTP |
| Program Memory Size | 768 B (512 x 12) | 768 B (512 x 12) | 1.5 kB (1024 x 12) | 1.5 kB (1024 x 12) | 1.5 kB (1024 x 12) | 768 B (512 x 12) |
| RAM Size | 25 B | 25 B | 41 B | 41 B | 25 B | 25 B |
| CPU Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Operating Voltage | 3 V to 5.5 V | 3 V to 5.5 V | 3 V to 5.5 V | 3 V to 5.5 V | 2 V to 5.5 V | 3 V to 5.5 V |
| Operating Temperature | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
| In-Circuit Serial Programming | No (OTP only) | No (OTP only) | No (OTP only) | No (OTP only) | Yes (Flash) | No (OTP only) |
Key Differentiators
- Industrial temperature grade in SOIJ-8 footprint (vs PIC12C508A-04/SM)
- Flash-reprogrammable successor in same footprint (vs PIC12F508-I/SM)
- Doubled program memory at same pin count (vs PIC12C509A-04I/SM)
Design Notes
Decouple Vdd (pin 8) with a 0.1 µF ceramic capacitor placed within 3 mm of the package, plus a 10 µF bulk capacitor at the regulator output. The internal RC oscillator draws brief current spikes during phase transitions, and inadequate decoupling can cause spurious resets via the POR circuit. For battery applications using two AA cells, expect roughly 1 mA active current at 4 MHz and 5 V — derate to 3 V to extend battery life by 30-40%.
OTP one-time programmability is irreversible: a single bit error during programming bricks the part. Always verify Vdd stability and programming voltage timing per the Microchip PIC12C5XX programming specification (DS40139E section 11). For new designs, prefer the Flash-based PIC12F508 family to allow firmware iteration; reserve the PIC12C508A-04I/SM for production runs where firmware is fully validated.
For the 8-SOIJ package, use a land pattern that matches JEDEC SO-8 footprint with extended pad clearances to accommodate the J-leads. Keep the MCLR/Vpp pin (pin 3) trace short and place the reset pull-up resistor within 5 mm to minimize EMI pickup that could trigger spurious resets. Expose a small copper pour under the package connected to Vss to improve thermal dissipation — the part dissipates < 100 mW typical but the SOIJ package benefits from even modest copper spreading.
Compliance Information
RoHS and REACH compliance per Microchip product declaration. Not AEC-Q100 qualified — choose PIC12C508A-I/SN automotive-grade part for AEC-Q100 contexts. Halogen-free status not explicitly listed in distributor data; consult Microchip product declaration.
