PIC12C671-04/P - 8-Bit 4MHz OTP MCU w/ ADC | Microchip | PDIP-8
MPN: PIC12C671-04/P β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.31 | $2.31 |
| 50 | $1.96 | $98.00 |
| 100 | $1.73 | $173.00 |
| 500 | $1.62 | $810.00 |
| 1,000 | $1.5 | $1,500.00 |
PIC12C671-04/P Overview
What is an 8-bit OTP microcontroller? An 8-bit OTP microcontroller is a small, low-cost, single-chip computer with a CPU datapath of 8 bits, on-chip non-volatile program memory that is one-time-programmable (can be written once and not erased), RAM for variables, integrated peripherals such as A/D converters, timers, and digital I/O. PIC microcontrollers sit within the broader taxonomy: 8-bit MCU -> microcontroller -> embedded controller -> semiconductor IC. The 12C family represents Microchip's mid-range baseline of OTP PIC MCUs in 8-pin packages.
The PIC12C671-04/P features a RISC CPU with only 35 single-word instructions, a hardware multiplier-free 8-bit ALU, 4MHz maximum clock at 4V-5.5V (or 10MHz at the same range for -10 speed grades), and DC to 4MHz operation at 3V-5.5V. On-chip peripherals include a 4-channel 8-bit ADC, an 8-bit timer/counter with 8-bit prescaler, a Watchdog Timer with its own on-chip RC oscillator, and a power-on reset. The 6 I/O pins are individually direction-controlled and provide 25mA source/sink capability per pin, sufficient to drive LEDs directly.
Typical applications for this device include low-cost consumer appliances, sensor signal conditioning with ADC readback, simple state machines for appliance control, battery chargers, automotive interior accessories (non-AEC-Q100 qualified), and any general-purpose 8-pin embedded control. The OTP memory suits production volumes where in-field firmware updates are not required.
When designing with this part, observe that the OTP memory requires one-time programming at production; budget for an emulator (PIC12C671 ICD or ICE) during development. The 6 I/O pins are shared with the ADC, so plan analog channel assignments carefully. The internal RC oscillator can be used or an external crystal/RC selected via configuration bits.
Drop-in alternatives for PIC12C671-04/P 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 PIC12C671-04/P (same form factor and footprint) β differing in Operating Temperature, Package, Timers, Watchdog Timer, Program Memory Size.
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PIC12C672-04/P
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PIC12F675-I/P
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PIC12C508A-04/P
β Drop-Inβ In Stock
$0.95 / Unit
View Datasheet βPIC12C509A-04/P
β Drop-Inπ Reference alternative (not in catalog)
PIC12C671-04/P Maximum Ratings & Electrical Characteristics
| Architecture | PIC 8-bit RISC |
| Core | 8-bit PIC |
| Maximum Clock Frequency | 4 MHz |
| Program Memory Size | 1.75 KB (1024 x 14) OTP |
| RAM Size | 128 bytes |
| EEPROM | Not present (CE674/675 variants only) |
| I/O Pins | 6 |
| ADC | 4 channels x 8-bit |
| Supply Voltage | 3.0 V to 5.5 V |
| Instruction Set Size | 35 single-word instructions |
| Timers | 1 x 8-bit with 8-bit prescaler |
| Watchdog Timer | Yes, with dedicated on-chip RC oscillator |
| Package | 8-Pin PDIP (P) |
| Operating Temperature | -40C to +85C (commercial/industrial) |
| I/O Sink/Source Current | 25 mA per pin |
| Mounting Type | Through-Hole |
| RoHS Status | Compliant |
PIC12C671-04/P Pin Configuration
| Pin 1 | GP5/OSC1/CLKIN β General-purpose I/O pin 5 / Oscillator crystal input / External clock input |
| Pin 2 | GP4/OSC2/CLKOUT β General-purpose I/O pin 4 / Oscillator crystal output / Clock output (Fosc/4) |
| Pin 3 | GP3/MCLR/VPP β General-purpose I/O pin 3 / Master Clear (reset, active low) / Programming voltage input |
| Pin 4 | GP2/AN2/TOCKI/INT β General-purpose I/O pin 2 / ADC channel 2 / Timer0 clock input / External interrupt |
| Pin 5 | GP1/AN1/VREF β General-purpose I/O pin 1 / ADC channel 1 / ADC voltage reference input |
| Pin 6 | GP0/AN0 β General-purpose I/O pin 0 / ADC channel 0 |
| Pin 7 | VDD β Positive supply voltage (3.0V to 5.5V) |
| Pin 8 | VSS β Ground reference |
Typical Applications
PIC12C671-04/P is suitable for 6 applications: Low-Cost Sensor Reading with ADC, Appliance Control State Machine, Battery-Operated Timer / Blinker, Automotive Interior Accessories (Non-Qualified), Replacement of Discrete Logic 555/Logic Gates, Educational and Hobbyist Embedded Projects.
Low-Cost Sensor Reading with ADC
The PIC12C671-04/P suits low-cost sensor front-ends where a handful of analog channels need to be digitized and processed locally. Its 4-channel 8-bit ADC provides 256 quantization levels over the 0-Vdd range, sufficient for thermistor voltage dividers, LDR photocells, or simple pressure sensor bridges. The 4MHz clock (1us instruction cycle) lets a single channel conversion complete in approximately 20us. Six I/O pins drive LEDs for status indication. The 3V-5.5V supply range aligns with two-AA alkaline battery stacks or a 5V regulated rail. Total BOM is the MCU plus a decoupling cap and the analog front-end.
Recommended
Appliance Control State Machine
Small household appliances (coffee makers, fan controllers, water heaters) often need a simple state machine that reads a few buttons and drives a relay or TRIAC. The PIC12C671-04/P fits this role with its 1.75KB OTP program memory, 25mA source/sink I/O, and on-chip watchdog timer. The watchdog prevents firmware lockup that could leave a heater element on. The 8-pin PDIP package simplifies through-hole assembly for low-volume products. OTP cost is justified when the firmware is finalized and production volumes are high enough that per-unit cost dominates the BOM.
Recommended
Battery-Operated Timer / Blinker
The 3.0V minimum supply and low-power design of PIC12C671-04/P suit battery-operated timer circuits, blinking LED markers, and replacement for 555-based pulse generators. With the internal RC oscillator and code-driven timing, an LED can be blinked at low frequency for months on a coin cell or AA pack. The watchdog timer with dedicated RC oscillator can wake the MCU from sleep at intervals without an external crystal. The 6 I/O pins allow multi-channel LED driving or low-side N-MOSFET switching.
Recommended
Automotive Interior Accessories (Non-Qualified)
PIC12C671-04/P is widely used in non-safety automotive interior accessories where AEC-Q100 qualification is not required: dome-light delay modules, simple turn-signal reminders, seat-position memory switches, and HVAC trim controls. Its 8-bit ADC reads potentiometers for trim position, the 25mA I/O sinks standard automotive indicator bulbs, and the 3-5.5V supply works from the 12V battery after a 7805 regulator. For safety-critical or under-hood automotive use, designers must choose AEC-Q100-qualified PIC16F equivalents instead.
Recommended
Replacement of Discrete Logic 555/Logic Gates
Designers frequently migrate legacy 555-timer and discrete-logic circuits to a PIC12C671-04/P for fewer parts and configurable timing. A single PIC replaces a 555 plus support components with software-defined period and duty cycle. The OTP memory holds the timing constants, 6 I/O pins handle multiple independent channels, and the 1us instruction cycle supports timing resolutions below 1ms. The result is one part on the BOM instead of several 555s, reducing assembly cost and increasing reliability.
Recommended
Educational and Hobbyist Embedded Projects
The PIC12C671-04/P is a popular choice in educational kits and hobbyist projects because of its simple 8-pin PDIP package (easy breadboarding), Microchip's free MPLAB X IDE, and the extensive PIC instruction-set literature. With only 35 instructions and 1.75KB of code space, beginners can complete small projects (LED chasers, digital dice, basic voltmeters) within a single lab session. The 4MHz internal RC oscillator eliminates the need for external crystals, and PICkit programmers target this part for quick in-circuit programming.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C671-04/P β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C672-04/P | PIC12F675-I/P | PIC12F683-I/P | PIC12C508A-04/P | PIC12C509A-04/P |
|---|---|---|---|---|---|---|
| Package | PDIP-8 | PDIP-8 (same) | PDIP-8 (same) | PDIP-8 (same) | PDIP-8 (same) | PDIP-8 (same) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 1.75 KB OTP | 3.5 KB OTP (+100%) | 1.75 KB Flash | 2 KB Flash | 0.75 KB OTP | 1.5 KB OTP |
| RAM | 128 B | 128 B | 64 B | 128 B | 25 B | 41 B |
| Max Clock | 4 MHz | 4 MHz | 20 MHz | 20 MHz | 4 MHz | 4 MHz |
| ADC | 4 ch x 8-bit | 4 ch x 8-bit | 4 ch x 10-bit | 4 ch x 10-bit | None | None |
| Memory Type | OTP | OTP | Flash | Flash | OTP | OTP |
| EEPROM | None | None | 64 B | 256 B | None | None |
| Approx Unit Price (qty 100) | $1.73 | $1.73 (same tier) | $1.85 (Flash premium) | $2.10 (Flash + PWM) | $1.45 (smaller memory) | $1.55 |
Key Differentiators
- On-chip 8-bit ADC with no external ADC required (vs PIC12C508A-04/P / PIC12C509A-04/P)
- Flash-based upgrade path with same pinout (vs PIC12F675-I/P)
- OTP-only architecture for ultra-low unit cost (vs PIC12F675-I/P)
Design Notes
PIC12C671-04/P uses one-time-programmable (OTP) program memory, which means each unit can only be programmed once. During development, design with the Flash-based PIC12F675-I/P (same 8-pin PDIP pinout) and migrate to PIC12C671-04/P only when firmware is finalized for production. Programming a code error into OTP memory bricks the device, wasting both the IC and the manufacturing slot.
Place a 0.1uF ceramic decoupling capacitor as close as physically possible to pins 7 (VDD) and 8 (VSS). Keep traces short (under 5mm). The ADC inputs are sensitive to supply noise; if ADC accuracy matters in your design, add a small RC filter (10 ohm + 100nF) between VDD and the PIC's VDD pin to attenuate switching noise from the same board.
Pin 3 is shared between GP3 (digital I/O), MCLR (reset), and VPP (programming voltage). If MCLR is enabled in configuration bits, pin 3 cannot be used as a general-purpose input without glitches on reset. To free pin 3 for digital I/O, disable MCLR in the configuration word, but understand that you lose the external hardware reset path. Use the internal Power-On Reset (POR) as compensation.
When using an external crystal (XT or HS oscillator modes), route the OSC1 and OSC2 traces symmetrically with short, parallel lengths and surround them with a ground pour to minimize stray capacitance. Keep the crystal within 5mm of the IC pins. If using the internal RC oscillator, leave the OSC1/OSC2 pins available as GP5/GP4 by selecting the INTRC configuration mode in the configuration word.
Compliance Information
PIC12C671-04/P is RoHS-compliant (lead-free PDIP package). Not AEC-Q100 qualified; for AEC-Q100 automotive designs, choose PIC16F or PIC18F equivalent parts instead.
