PIC12C671-04I/P - 4MHz 8-Bit OTP MCU, 1.75KB | Microchip
MPN: PIC12C671-04I/P β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.37 | $4.37 |
| 10 | $3.92 | $39.20 |
| 100 | $3.49 | $349.00 |
| 500 | $2.95 | $1,475.00 |
| 1,000 | $2.55 | $2,550.00 |
PIC12C671-04I/P Overview
An 8-bit microcontroller (MCU) is a single-chip computer with an 8-bit data path, ALU, program memory, data memory, and peripheral set, intended to handle control and simple DSP tasks in embedded systems. PIC microcontrollers belong to the Harvard-architecture RISC MCU family, separated by the parent category of microcontrollers within Integrated Circuits. The PIC12C family is Microchip's baseline 8-pin line, positioned below PIC16 and PIC18 families for cost-sensitive applications. PIC12C671-04I/P is an OTP (one-time-programmable) variant, meaning program memory is written once and is not electrically erasable; the Flash-based counterpart is the PIC12F675, which is recommended by Microchip as the modern replacement.
Key features include 35 single-word instructions, 8-bit timer/counter (TMR0) with 8-bit prescaler, watchdog timer with on-chip RC oscillator, power-on reset, power-saving Sleep mode, in-circuit serial programming (ICSP), and four analog input channels multiplexed onto GP0/GP1/GP3/GP4. The 4 MHz oscillator option (-04) supports a 1 us instruction execution time at 4 MHz. Brown-out reset is not present on the PIC12C671; the chip relies on power-on reset and the internal RC watchdog for reliable startup. The 6 I/O pins each source/sink up to 25 mA, sufficient to drive LEDs directly.
Typical applications include battery chargers, security systems, remote transmitters, low-end sensors, smart cards, and small appliance controls. The integrated ADC eliminates the need for an external analog front end in simple sensor-interface designs. Industrial users favor the -04I/P variant for its wide temperature range and through-hole PDIP packaging that simplifies hand-prototyping and field repair.
When designing with the PIC12C671-04I/P, allocate one I/O pin (GP3) as the ICSP clock and another (GP1) as ICSP data when in-circuit programming is required. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of the pin. For analog readings, add a 100 nF + 10 uF decoupling pair and an RC anti-aliasing filter on each analog input. Note that OTP parts cannot be firmware-updated in the field, so design with a Flash equivalent (PIC12F675) if post-production reprogramming is required.
This page combines distributor pricing, drop-in same-package alternatives, and engineering design notes that complement but do not replace the manufacturer datasheet.
Drop-in alternatives for PIC12C671-04I/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 PIC12C671-04I/P (same form factor and footprint) β differing in Operating Temperature, Package, RoHS Status, Watchdog Timer, Program Memory Size.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC12C672-04I/P
β Drop-Inπ Reference alternative (not in catalog)
PIC12C671-04/P
β Drop-Inβ In Stock
$1.5 / Unit
View Datasheet βPIC12C671-04I/MF
β Drop-Inβ In Stock
$1.55 / Unit
View Datasheet βPIC12C671-04E/P
β Drop-Inβ In Stock
$2.3 / Unit
View Datasheet βPIC12CE673-04I/P
β Drop-Inπ Reference alternative (not in catalog)
PIC12CE674-04I/P
β Drop-Inπ Reference alternative (not in catalog)
PIC12C671-04I/P Maximum Ratings & Electrical Characteristics
| Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.75 KB (1K x 14 words) |
| RAM | 128 bytes |
| EEPROM | 0 bytes (no on-chip EEPROM on PIC12C671) |
| CPU Speed | 4 MHz (-04 speed grade) |
| Instruction Cycle | 1 us at 4 MHz (400 ns at 10 MHz) |
| Instruction Set | 35 single-word instructions |
| I/O Pins | 6 |
| ADC | 8-bit, 4 channels |
| Timers | 1 x 8-bit (TMR0 with prescaler) |
| Watchdog Timer | Yes (with internal RC oscillator) |
| Supply Voltage | 2.5 V to 5.5 V |
| Operating Temperature | -40 C to +85 C (Industrial, 'I' suffix) |
| Package | 8-pin PDIP ('P' suffix) |
| Pin/Package Code | DIP-8 |
| Mounting Type | Through-Hole |
| I/O Source/Sink Current | 25 mA per pin |
| Programming Method | ICSP (In-Circuit Serial Programming) |
| Power-Saving Mode | Sleep mode |
| RoHS Status | Non-compliant (legacy PDIP process, RoHS exemption 7a applies) |
PIC12C671-04I/P Pin Configuration
| Pin 1 | GP2/AN2/T0CKI/COUT β GPIO 2 / analog input 2 / TMR0 clock input / comparator output |
| Pin 2 | GP3/MCLR/VPP β GPIO 3 / master clear reset (active low) / programming voltage input |
| Pin 3 | GP4/AN3/T1G/OSC2/CLKOUT β GPIO 4 / analog input 3 / TMR1 gate / oscillator output / clock out |
| Pin 4 | GP5/OSC1/CLKIN β GPIO 5 / oscillator input / external clock input |
| Pin 5 | VSS β Ground reference |
| Pin 6 | GP0/AN0/ICSPDAT β GPIO 0 / analog input 0 / ICSP data |
| Pin 7 | GP1/AN1/ICSPCLK β GPIO 1 / analog input 1 / ICSP clock |
| Pin 8 | VDD β Positive supply voltage (2.5V to 5.5V) |
Typical Applications
PIC12C671-04I/P is suitable for 6 applications: Battery Charger Controllers, Remote RF Transmitters (Key Fobs), Security System Sensors (PIR / Reed Switch), Small Appliance Motor Control, Smart Card and Token Readers, Industrial Sensor Interfaces (4-20 mA Loop Powered).
Battery Charger Controllers
Why PIC12C671-04I/P fits: The PIC12C671-04I/P's 4-channel 8-bit ADC monitors battery voltage and charge current with sufficient resolution for lead-acid and NiMH charging profiles. How it's used: One ADC channel reads the battery via a resistor divider, a second reads charge current via a sense resistor, and the firmware regulates a PWM-driven MOSFET or relay via TMR0. Performance consideration: At 4 MHz, the firmware runs a 1 ms PID control loop easily; the 1.75 KB program memory fits full CC/CV/termination algorithms including temperature compensation. Industrial temperature rating supports under-hood automotive and outdoor solar installations.
Recommended
Remote RF Transmitters (Key Fobs)
Why PIC12C671-04I/P fits: The 6 I/O pins are sufficient to drive 4 buttons plus an SAW resonator-based TX stage, while the 25 mA per-pin source current directly switches a 433 MHz oscillator without a buffer transistor. How it's used: Sleep mode draws < 1 uA, extending coin-cell life to multiple years; button press wakes the MCU, reads the keypad, and streams a rolling-code sequence to the TX. Performance consideration: The 4 MHz instruction rate is fast enough to bit-bang OOK modulation at 1-10 kbps; the 1.75 KB program memory holds rolling-code tables for 16+ remotes.
Recommended
Security System Sensors (PIR / Reed Switch)
Why PIC12C671-04I/P fits: The integrated ADC reads the PIR analog output directly without external circuitry, while 6 I/O pins drive a PIR sensor, reed switch, status LED, piezo buzzer, and a wireless TX line. How it's used: Sleep current is under 1 uA, so a PIR sensor running from 2x AAA batteries lasts 2+ years; the MCU wakes on PIR trigger, validates the signal via ADC threshold, then pulses the TX. Performance consideration: The industrial -40C to +85C temperature range is essential for outdoor PIR sensors in cold-climate security installations.
Recommended
Small Appliance Motor Control
Why PIC12C671-04I/P fits: TMR0 generates PWM for brushed DC motor speed control up to 4 MHz PWM resolution, and 25 mA I/O drives small MOSFET gates directly. How it's used: One ADC channel reads a potentiometer speed input, firmware implements PI control with closed-loop feedback from a tachometer or back-EMF ADC channel. Performance consideration: The 1.75 KB program memory holds full soft-start, current limit, and fault-recovery routines for fans, mixers, and small pumps rated under 50W.
Recommended
Smart Card and Token Readers
Why PIC12C671-04I/P fits: The 6 I/O pins interface to a single UART-style smart card or RFID reader, and the OTP memory prevents reverse-engineering of secret keys. How it's used: Firmware implements ISO 7816 T=0/T=1 or 13.56 MHz RFID protocols in bit-banged I/O, using TMR0 for character timing. Performance consideration: The 1.75 KB program memory holds the full DES/AES-light authentication stack for a single application; OTP prevents attackers from reading the key material even with a chip decapsulation.
Recommended
Industrial Sensor Interfaces (4-20 mA Loop Powered)
Why PIC12C671-04I/P fits: The 2.5V minimum supply voltage and low-power operation suit 4-20 mA loop-powered sensors; the integrated ADC digitizes bridge or RTD signals directly. How it's used: One ADC channel reads the loop current via a 250 ohm sense resistor; firmware linearizes the reading and drives a 4-20 mA output via PWM-filtered current pump. Performance consideration: The industrial -40C to +85C rating is essential for process-control installations; the 1.75 KB program memory holds polynomial linearization for RTDs and load-cell calibration tables.
Recommended
Recommended Products Summary
Engineering reference data for PIC12C671-04I/P β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12C672-04I/P | PIC12C671-04/P | PIC12C671-04E/P | PIC12CE673-04I/P | PIC12CE674-04I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | PDIP-8 | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same | PDIP-8 - same |
| Program Memory | 1.75 KB OTP | 2 KB OTP (+14%) | 1.75 KB OTP (same) | 1.75 KB OTP (same) | 1 KB OTP + 16B EEPROM | 2.25 KB OTP + 16B EEPROM |
| CPU Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| ADC | 8-bit, 4 channels | 8-bit, 4 channels | 8-bit, 4 channels | 8-bit, 4 channels | 8-bit, 4 channels | 8-bit, 4 channels |
| RAM | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 128 bytes |
| EEPROM | None | None | None | None | 16 bytes | 16 bytes |
Key Differentiators
- Same-die upgrade path to PIC12C672 with more program memory (vs PIC12C672-04I/P)
- Industrial temperature grade (-40C to +85C) (vs PIC12C671-04/P)
- On-chip EEPROM option in CE variants (vs PIC12CE673-04I/P)
- Largest program memory in CE family (vs PIC12CE674-04I/P)
Design Notes
Decouple VDD (pin 8) with a 100 nF ceramic capacitor placed within 5 mm of the pin. For analog applications using the ADC, add a 10 uF tantalum or aluminum polymer bulk capacitor in parallel. PIC12C671 has no internal brown-out reset, so for reliable operation across a noisy industrial supply, add an external voltage supervisor (e.g., MCP130 or MCP120) tied to MCLR if the design operates below 4.0V or in environments with motor switching transients. Without brown-out, firmware can execute from corrupted Flash under low-voltage conditions.
Place the 4 MHz ceramic resonator (or crystal + 22 pF caps) within 5 mm of OSC1 (pin 4) and OSC2 (pin 3). Route oscillator traces short and direct, with a ground guard ring on the PCB layer directly beneath. Avoid routing digital switching signals or PWM traces under or adjacent to the oscillator traces; cross only at right angles if absolutely required. Keep analog input traces (GP0/GP1/GP3/GP4) away from I/O switching traces by at least 3 mm to minimize ADC crosstalk.
PIC12C671 is OTP (one-time-programmable); firmware cannot be updated in the field. Verify all firmware logic before final write. GP3 is shared between GPIO and MCLR/VPP - configuring GP3 as a digital output disables the external reset function, which can complicate ICSP programming. Always configure GP3 as input or leave it unused if MCLR reset is required. The ADC reference voltage defaults to VDD; for accurate readings, use a separate low-noise 5V reference (e.g., MCP1541) or rely on VDD with adequate decoupling.
When using the ICSP interface, GP1 and GP0 must be isolated from external circuitry that drives these pins strongly during programming; use series resistors (10 kohm) or a buffer to prevent contention. The MCLR/VPP pin requires a 13V VPP pulse during bulk programming; ensure the in-circuit reset supervisor does not clamp this voltage. Per Microchip's ICSP specification, target capacitance on ICSPCLK should remain below 50 pF to maintain programming signal integrity; long programming cables require buffering.
Compliance Information
Lead-bearing PDIP package qualifies for RoHS exemption 7a (lead in server/storage/socket/connector applications) and exemption 7c-I (lead in glass/ceramic of electronic components). For RoHS-compliant portable/consumer designs, use the PIC12F675 in DFN/SOIC packaging instead. REACH compliance verified; conflict-mineral reporting per CFSI template available from Microchip.
