PIC12F635-I/MF - 8-Bit MCU, 20MHz, 1.75KB Flash, 8-DFN | Microchip
MPN: PIC12F635-I/MF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.28 | $12.80 |
| 100 | $1.12 | $112.00 |
| 500 | $0.99 | $495.00 |
| 1,000 | $0.88 | $880.00 |
PIC12F635-I/MF Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, RAM, and peripherals on a single die. The PIC10/12 family of mid-range core MCUs is widely used as cost-optimized glue logic and sensor interface controllers in space-constrained designs. Within the broader taxonomy, PIC12F635 belongs to the enhanced mid-range 8-bit MCU category, with its RISC single-cycle instruction set delivering deterministic interrupt latency and ~5 MIPS peak throughput at 20 MHz, suitable for deterministic control loops where a 32-bit MCU would be over-spec.
Key features include nanoWatt power management with multiple sleep modes (typically sub-1 uA standby), a hardware USART/SPI/I2C-capable EUSART block on selected variants, internal 4 MHz and 31 kHz oscillators reducing external component count, and Microchip's In-Circuit Serial Programming (ICSP) interface for field upgrades. The on-chip enhanced comparator supports analog signal conditioning without an external op-amp, while two timer/counters and a watchdog timer enable closed-loop control and fail-safe operation. Programming is supported by the free MPLAB X IDE and XC8 compiler toolchain.
The device targets cost-sensitive 8-bit applications including PIR motion sensor signal chains, battery-powered remote controls, LED driver controllers, fan/relay control, security PIR front-ends, simple sensor nodes, and consumer appliance user-interface sub-MCUs. Its 8-pin DFN package keeps the board footprint to roughly 6x5 mm while exposing six I/O pins through multiplexed peripheral functions. Typical designs pair the PIC12F635-I/MF with a 3V coin cell or USB-powered linear regulator, a small EEPROM or sensor on the I2C bus, and a low-side MOSFET or opto-triac load driver.
When designing with the PIC12F635-I/MF, ensure decoupling is placed within 3 mm of VDD with at least a 100 nF X7R ceramic plus a bulk tantalum. Reserve GP3/MCLR for the ICSP programming header unless the internal MCLR disable is configured, and respect the 20 MHz maximum Fosc when VDD drops below 4.5V (4.5V-5.5V required for full-speed operation). This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC12F635-I/MF — 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 PIC12F635-I/MF (same form factor and footprint) — differing in Package, MSL Level, ADC, Core Architecture, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12F635-E/MF
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →PIC12F635T-I/MF
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F1840-E/MF
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.84 / Unit
View Datasheet →PIC12F1571-E/MF
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC12F1501T-I/MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.74 / Unit
View Datasheet →PIC12F1572-I/MS
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.72 / Unit
View Datasheet →PIC12F635-I/MF Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC12 enhanced mid-range 8-bit RISC |
| Program Memory (Flash) | 1.75 KB (1K x 14 words) |
| Data SRAM | 64 bytes |
| Data EEPROM | 128 bytes |
| Maximum Clock Speed | 20 MHz |
| Operating Voltage Range | 2.0 V to 5.5 V (4.5 V-5.5 V for full 20 MHz) |
| I/O Pins | 6 |
| Package | 8-pin DFN-S (6x5 mm) |
| Operating Temperature Range | -40 C to +85 C (industrial) |
| Peripherals | Enhanced Comparator, 2 Timers, WDT, BOD, POR, EUSART |
| ADC | None (analog via comparator only) |
| Internal Oscillator | 4 MHz and 31 kHz selectable |
| Programming Interface | ICSP (In-Circuit Serial Programming) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| MSL Level | 1 |
| Peak Throughput | 5 MIPS at 20 MHz |
PIC12F635-I/MF Pin Configuration
| Pin 1 | VDD — Positive supply voltage (2.0V to 5.5V) |
| Pin 2 | GP5/T1CKI/OSC1/CLKIN — General-purpose I/O / Timer1 clock input / external oscillator input |
| Pin 3 | GP4/AN3/T1G/OSC2/CLKOUT — General-purpose I/O / Timer1 gate / oscillator output / clockout |
| Pin 4 | GP3/MCLR/VPP — General-purpose I/O / Master Clear (reset, active low) / ICSP programming voltage |
| Pin 5 | GP2/COUT/T0CKI/INT — General-purpose I/O / Comparator output / Timer0 clock / external interrupt |
| Pin 6 | GP1/CIN-/ICSPCLK — General-purpose I/O / Comparator inverting input / ICSP clock |
| Pin 7 | GP0/CIN+/ICSPDAT — General-purpose I/O / Comparator non-inverting input / ICSP data |
| Pin 8 | VSS — Ground reference |
Typical Applications
PIC12F635-I/MF is suitable for 6 applications: PIR Motion Sensor Front-End, Battery-Powered Remote Control, LED Lighting Controller, Small Fan or Relay Controller, Security PIR Sensor Hub, Consumer Appliance User Interface.
PIR Motion Sensor Front-End
The PIC12F635-I/MF fits PIR motion sensor signal chains because it integrates a low-power enhanced comparator to directly condition the PIR op-amp output and a 20 MHz mid-range core for envelope detection. With nanoWatt sleep currents typically sub-1 uA and a 2.0V-5.5V supply range, it can run on two AA cells for multi-year battery life. The six I/O pins drive the alarm LED, relay or opto-triac load, and PIR analog front-end without an external ADC. The 8-pin DFN package fits behind the Fresnel lens housing. Practical designs pair it with a Microchip MCP73831 Li-ion charger or a 3V linear regulator and use the internal comparator to set the detection threshold without external op-amps.
Recommended
Battery-Powered Remote Control
The PIC12F635-I/MF's 2.0V-5.5V supply, 1.75 KB Flash, and nanoWatt sleep modes make it a natural choice for coin-cell or 2xAAA remote controls. The internal 31 kHz oscillator drives a low-duty-cycle keypad scan loop with sub-uA quiescent current, and the 20 MHz fast clock wakes on interrupt to handle IR or RF transmission bursts. The 8-pin DFN package fits inside a slim remote housing, leaving room for a coin cell and a PCB antenna for sub-GHz transmit. Real-world designs use PICkit-programmed custom IR protocols and rely on the brown-out detect (BOD) to prevent brown-out-induced lockups during battery end-of-life.
Recommended
LED Lighting Controller
The PIC12F635-I/MF drives low-end LED lighting controllers by using the enhanced comparator to sense a potentiometer or photodiode for brightness control and one of its timers to generate PWM for LED dimming. With 20 MHz throughput, it can implement soft-fade transitions and color-mixing state machines in firmware while still leaving 70-80% of the 1.75 KB Flash for application code. The 8-pin DFN package drops into a recessed LED driver PCB, and the -40C to +85C range covers indoor fixtures and outdoor enclosures. Designers typically pair it with a low-side N-channel MOSFET like the DMG3415U for PWM dimming.
Recommended
Small Fan or Relay Controller
The PIC12F635-I/MF handles small fan speed controllers or relay switching where deterministic on/off control plus RPM feedback matters more than computing horsepower. The enhanced comparator reads back-EMF or tachometer pulses from a 2-wire fan, while one timer generates the PWM drive and another handles the watchdog. Operating from 2.0V to 5.5V supports 3.3V and 5V rails, and the industrial temperature range tolerates under-hood or appliance interior environments. The 6 I/O pins map cleanly to fan-tach input, PWM output, fault LED, and a serial debug port.
Recommended
Security PIR Sensor Hub
The PIC12F635-I/MF acts as a low-cost sensor hub in distributed security systems by aggregating one PIR or reed-switch input via the comparator and forwarding state over a single-wire UART link to a master controller. Its 128-byte EEPROM stores calibration and tamper-detection parameters, while the 1.75 KB Flash holds the simple state-machine firmware. The 8-pin DFN package mounts on a tiny sensor carrier PCB that fits inside a door-frame junction box, and the -I industrial temperature grade covers outdoor and unheated garage installations.
Recommended
Consumer Appliance User Interface
The PIC12F635-I/MF serves as a sub-MCU in appliance user-interface boards, scanning 2-3 mechanical buttons and driving 2-3 indicator LEDs. The enhanced comparator wakes the device from sleep on button press via a resistor-divider network, allowing the rest of the system to stay in deep sleep until user interaction. The internal 4 MHz oscillator provides accurate timing for debounce and LED blink patterns without external crystals. The DFN-8 package measures only 6x5 mm, fitting comfortably behind a small appliance front-panel PCB alongside a 7-segment display driver.
Recommended
Recommended Products Summary
Engineering reference data for PIC12F635-I/MF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12F635-E/MF | PIC12F635T-I/MF | PIC12F1840-E/MF | PIC12F1571-E/MF | PIC12F1501T-I/MU | PIC12F1572-I/MS |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-pin DFN-S (6x5 mm) | 8-pin DFN-S (6x5 mm) - same | 8-pin DFN-S (6x5 mm) - same | 8-pin DFN-S (6x5 mm) - same | 8-pin DFN-S (6x5 mm) - same | 8-pin DFN-S - same family | 8-pin DFN-S - same family |
| Flash Memory | 1.75 KB | 1.75 KB | 1.75 KB | 7 KB | 1.75 KB | 1.75 KB | 3.5 KB |
| SRAM | 64 bytes | 64 bytes | 64 bytes | 256 bytes | 128 bytes | 64 bytes | 128 bytes |
| EEPROM | 128 bytes | 128 bytes | 128 bytes | 256 bytes | unlisted | unlisted | unlisted |
| Maximum Clock | 20 MHz | 20 MHz | 20 MHz | 32 MHz | 20 MHz | 20 MHz | 20 MHz |
| ADC | None (comparator only) | None | None | 10-bit | 10-bit | 10-bit | 10-bit |
| Operating Temperature | -40 C to +85 C | -40 C to +125 C | -40 C to +85 C | -40 C to +125 C | -40 C to +125 C | -40 C to +85 C | -40 C to +85 C |
Key Differentiators
- Lowest-cost 8-bit MCU with hardware comparator in 8-pin DFN (vs PIC12F675-I/MF)
- 4x more code space on a same-footprint upgrade path (vs PIC12F1840-E/MF)
- Extended temperature grade in identical DFN-8 package (vs PIC12F635-E/MF)
Design Notes
Decouple VDD (pin 1) with a 100 nF X7R ceramic placed within 3 mm of the package, plus a 4.7-10 uF bulk capacitor on the upstream rail. The PIC12F635-I/MF draws ~100 uA/MIPS active and sub-1 uA in sleep, so a low-Iq LDO such as MCP1700 is recommended for battery-powered designs. Estimated: at 20 MHz active with 5V VDD the core draws ~2 mA; verify with the PIC12F635 family datasheet power curves section.
Reserve GP3/MCLR (pin 4) for the ICSP programming header unless the internal MCLR disable configuration bit is set, in which case GP3 becomes a general-purpose input. Route the ICSP header to a 5-pin 0.1-inch header footprint so the PICkit can be attached without disassembly. The 8-pin DFN has an exposed pad (EP) on the underside that should be soldered to the PCB ground pour for thermal dissipation and mechanical strength.
Keep the ICSP traces short and away from switching nodes; if the design includes an analog front-end driven by the on-chip comparator, route CIN+ and CIN- (pins 6 and 7) as a differential pair with a ground guard on either side. Avoid running high-current traces under the DFN-8 thermal pad to prevent ground-bounce coupling into the analog comparator reference. Use a single ground pour stitched with vias around the MCU for low-impedance return paths.
Do not exceed 20 MHz Fosc below 4.5V VDD; the PIC12F635 datasheet's electrical characteristics specify that 20 MHz operation requires 4.5V-5.5V. Below 4.5V, Fosc derates to 10 MHz (2.0V-4.5V). Forgetting this is the most common cause of erratic behavior at low battery voltage. Also remember that the PIC12F635 has no ADC; do not connect analog sensors to GP0-GP5 expecting ADC readings - use the enhanced comparator or migrate to PIC12F675/PIC12F683 if an ADC is required.
When using the internal comparator for PIR or thermopile sensing, add a small RC low-pass filter on the comparator input to suppress switching-noise spikes from nearby digital lines. The comparator output (COUT on GP2) can be configured as an interrupt source to wake the MCU from sleep, which is essential for battery-powered motion detectors. Keep the comparator input traces short and surrounded by ground to minimize pickup from the ICSP clock line.
Compliance Information
RoHS compliant per Microchip material declaration. AEC-Q100 not qualified - choose PIC12F635-E/MF for extended temperature or PIC16F1xxx AEC-Q100 variants for automotive. Halogen-free status not explicitly stated in retrieved data.
