PIC12F635-I/MD - 8-bit Flash MCU, 1.75KB, 20MHz, 8-DFN | Microchip
MPN: PIC12F635-I/MD ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.92 | $1.92 |
| 10 | $1.78 | $17.80 |
| 100 | $1.55 | $155.00 |
| 500 | $1.36 | $680.00 |
| 1,000 | $1.18 | $1,180.00 |
PIC12F635-I/MD Overview
An 8-bit PIC microcontroller is a RISC-based single-chip computer built around a Harvard architecture that separates program and data memory, enabling simultaneous instruction fetch and data access. The PIC12 sub-family targets ultra-compact, low-pin-count designs where 6 or fewer I/O lines are sufficient - typical examples include appliance controls, sensor nodes, remote keyless entry, and small motor drivers. Compared to larger PIC16/PIC18 devices, the PIC12 family sacrifices peripherals and memory for the smallest possible PCB footprint, making it the de facto choice when board area is at a premium.
Key features of the PIC12F635 include a precision 8 MHz internal oscillator with PLL for 32 kHz to 20 MHz operation, an integrated analog comparator, a 10-bit ADC (not present on all 8-pin PIC12s - the PIC12F635 specifically excludes this), a hardware UART (EUART), capture/compare/PWM (CCP) module, and a watchdog timer with its own on-chip low-power oscillator. The device also supports in-circuit serial programming (ICSP) and in-circuit debugging (ICD) via two dedicated pins. nanoWatt features include Sleep mode currents in the microamp range, multiple oscillator options, and peripheral module disable to quiesce unused functions.
Typical applications include remote-control transmitters, sensor signal conditioning, automotive RKE (remote keyless entry) receivers, security-system peripherals, battery chargers, LED drivers, and small consumer appliances. The 8-pin DFN package reduces PCB area by approximately 85% versus the PDIP-8 equivalent, enabling use in space-constrained designs such as wearable patches, RFID transponders, and IoT edge nodes.
When designing with this part, leave the ICSPDAT/ICSPCLK pins accessible (RA0/RA1) for production programming and debugging. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of the package, and connect the exposed thermal pad to ground for improved thermal dissipation and mechanical solder joint reliability.
This page synthesizes Microchip datasheet specifications, current distributor pricing, and drop-in same-package alternatives (PIC12F635-I/MF, PIC12F609-I/MD, PIC12F615-I/MD) not aggregated in a single view elsewhere.
Drop-in alternatives for PIC12F635-I/MD — 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/MD (same form factor and footprint) — differing in Package, Core Architecture, Operating Temperature Range, Peripherals, Program Memory (Flash).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12F635-I/MF
✅ Drop-In✓ In Stock
$0.88 / Unit
View Datasheet →PIC12F635-E/MD
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F635-E/MF
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →PIC12F609-I/MD
✅ Drop-In✓ In Stock
$0.71 / Unit
View Datasheet →PIC12F615-I/MD
✅ Drop-In✓ In Stock
$0.64 / Unit
View Datasheet →PIC12F635-I/MD Maximum Ratings & Electrical Characteristics
| Series | PIC12 |
| Core Processor | PIC |
| Core Size | 8-bit |
| Maximum Clock Speed | 20 MHz |
| Program Memory Size | 1.75 KB (1K x 14) Flash |
| RAM Size | 64 bytes |
| EEPROM Size | 128 bytes |
| Number of I/O | 6 |
| Supply Voltage Range | 2.0 V to 5.5 V |
| Operating Temperature Range | -40 °C to +85 °C (Industrial) |
| Package | 8-pin DFN (4x4 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Oscillator Type | Internal 8 MHz with PLL (32 kHz to 20 MHz), External optional |
| Peripherals | Brown-out Detect, Comparator, WDT, EUART, ICSP/ICD |
| Program Memory Type | Flash (self-programmable) |
| RoHS Status | Compliant |
| Lead Free | Yes |
PIC12F635-I/MD Pin Configuration
| Pin 1 | RA3/MCLR/VPP — GPIO RA3 / Master Clear reset (active-low) / ICSP programming voltage input |
| Pin 2 | RA0/ICSPDAT/AN0 — GPIO RA0 / ICSP data / analog input AN0 / comparator reference |
| Pin 3 | RA1/ICSPCLK/AN1 — GPIO RA1 / ICSP clock / analog input AN1 |
| Pin 4 | RA2/AN2/CVREF/C1OUT — GPIO RA2 / analog input AN2 / comparator Vref output / C1 output |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RA4/AN3/C1IN-/T1G/OSC2/CLKOUT — GPIO RA4 / analog input AN3 / comparator C1 inverting input / Timer1 gate / OSC2 / CLKOUT |
| Pin 7 | RA5/AN4/C1IN+/OSC1/CLKIN — GPIO RA5 / analog input AN4 / comparator C1 non-inverting input / OSC1 / CLKIN |
| Pin 8 | VDD — Positive supply voltage (2.0 V to 5.5 V) |
| Pin EP | EP — Exposed thermal pad - solder to ground plane for thermal dissipation and mechanical reliability |
Typical Applications
PIC12F635-I/MD is suitable for 6 applications: Remote Keyless Entry (RKE) Receiver, Industrial Sensor Signal Conditioning, Battery-Powered IoT Edge Node, Security System Peripheral Module, LED Lighting Controller, Small Consumer Appliance Control.
Remote Keyless Entry (RKE) Receiver
The PIC12F635-I/MD is well-suited for automotive remote keyless entry receiver modules because its 20 MHz CPU clock can decode rolling-code Manchester or KEELOQ transmissions in real time while the integrated EUART streams decoded commands to the body control module. The 128 bytes of EEPROM store rolling-code synchronization counters and learned transmitter IDs across power cycles, eliminating the need for an external EEPROM chip. The 6 I/O pins map directly to the RKE receiver chain: one for ASK/FSK demodulated data input, one for the learn-mode push button, and one each for status LED, relay driver, and the host UART TX/RX. With Sleep current under 1 µA in nanoWatt mode, the part can be parked in a battery-backed quiescent state for years without draining the car battery, while a GPIO interrupt wakes it on the first edge of an incoming transmission. Pin-compatible alternatives (PIC12F635-E/MD automotive variant) extend the temperature range for under-hood installations.
Recommended
Industrial Sensor Signal Conditioning
For low-power industrial sensor signal-conditioning front ends, the PIC12F635-I/MD provides an integrated analog comparator that can directly compare a sensor bridge output against an internal programmable voltage reference, eliminating the need for a dedicated comparator IC. The EUART then streams the comparator trip events (or a derived duty cycle) to a host PLC or gateway over RS-232 / RS-485 with TTL-level translation. The 2.0-5.5 V supply range allows direct operation from a 3.3 V regulated rail or a 2-cell alkaline battery pack for remote wireless sensor nodes. Six I/O pins are sufficient to drive a status LED, accept a calibration push button, and read the analog comparator output plus the EUART TX/RX pair, leaving one GPIO spare for a watchdog expander. The 20 MHz instruction throughput enables real-time debouncing and event counting without burdening the host controller, and the nanoWatt Sleep mode keeps quiescent current under 1 µA between transmissions.
Recommended
Battery-Powered IoT Edge Node
The PIC12F635-I/MD is an ideal MCU for the always-listening control plane of an IoT edge node that wakes up a higher-power radio (LoRa, BLE, sub-GHz) only when meaningful sensor events occur. The nanoWatt Sleep mode draws under 1 µA, so a CR2032 coin cell can power the part for 10+ years while it polls the analog comparator for threshold crossings or GPIO edges. On wake, the 20 MHz CPU processes the event, logs it to the 128-byte EEPROM (sufficient for ~80 timestamped events), and uses the integrated EUART to forward the data to a host processor at 9600-115200 baud. The 8-pin DFN (4x4 mm) footprint reduces PCB area by 85% versus the PDIP-8 equivalent, fitting inside the smallest wearable patches and RFID-style tags. With 1.75 KB of Flash, the firmware comfortably fits a state machine, comparator ISR, and a simple command parser for in-field reconfiguration via ICSP.
Recommended
Security System Peripheral Module
In security-system peripherals - PIR sensor modules, glass-break detectors, door/window contact transmitters - the PIC12F635-I/MD provides the ultra-low Sleep current and integrated analog comparator needed for years-long battery life. The internal comparator continuously watches the PIR amplifier output against a programmable threshold while the CPU sleeps in nanoWatt mode at under 1 µA. On a trip event, the part wakes, debounces the input, and uses the EUART (or firmware bit-banging) to transmit a coded alarm message to the central panel. The 128-byte EEPROM stores the device's unique transmitter ID and zone configuration. Six I/O pins map cleanly to a tamper switch input, alarm LED, learn-mode button, and the EUART TX/RX pair. The 2.0-5.5 V supply range allows direct operation from a single CR123A lithium primary cell, while the -40 °C to +85 °C industrial rating covers unheated attics and outdoor soffit installations.
Recommended
LED Lighting Controller
The PIC12F635-I/MD serves as a compact, low-cost controller for standalone LED drivers - decorative lighting strips, signage, and architectural fixtures - where it manages on/off scheduling, color sequencing, and brightness PWM via the integrated Capture/Compare/PWM (CCP) module. The EUART accepts configuration commands from a master controller or DMX-style receiver, while the 128-byte EEPROM retains the last-set brightness and color pattern across power cycles. Operating directly from a 5 V supply (regulated from the LED driver's high-voltage rail), the PIC12F635 dissipates negligible power itself, leaving the thermal budget to the LED driver stage. The 8-pin DFN package fits inside the tightest inline LED controllers, and the -40 °C to +85 °C rating covers outdoor installations. For higher-current applications requiring 10-bit dimming resolution, the pin-compatible PIC12F615-I/MD drops in directly with its enhanced PWM and ADC.
Recommended
Small Consumer Appliance Control
For small consumer appliances such as electric toothbrushes, hair clippers, kitchen timers, and personal-care devices, the PIC12F635-I/MD offers the right balance of features and cost. The 20 MHz CPU drives button-debounced state machines, the EUART interfaces with a host debug port or BLE module for firmware updates, and the internal comparator implements battery-low detection against an internal reference without external components. The 128-byte EEPROM stores usage counters, calibration data, and last-mode settings across battery swaps. Six I/O pins are sufficient for a power button, mode switch, status LED, motor enable, and a charging-sense input. The nanoWatt Sleep mode keeps standby current below 1 µA, preserving coin-cell and rechargeable battery life. The 8-pin DFN (4x4 mm) package fits inside toothbrush handles and other space-constrained enclosures, and the wide 2.0-5.5 V supply accommodates single-cell Li-ion, 2x AA, and USB-derived 5 V rails.
Recommended
Recommended Products Summary
Engineering reference data for PIC12F635-I/MD — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12F635-I/MF | PIC12F635-E/MD | PIC12F609-I/MD | PIC12F615-I/MD |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-pin DFN (4x4 mm) | 8-pin DFN (6x5 mm) - same pinout | 8-pin DFN (4x4 mm) - identical | 8-pin DFN (4x4 mm) - identical | 8-pin DFN (4x4 mm) - identical |
| Core / Architecture | PIC 8-bit, baseline | PIC 8-bit, baseline | PIC 8-bit, baseline | PIC 8-bit, baseline | PIC 8-bit, enhanced midrange |
| Flash Memory | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) |
| RAM | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes |
| EEPROM | 128 bytes | 128 bytes | 128 bytes | None (0 bytes) | None (0 bytes) |
| Hardware EUART | Yes (1 module) | Yes (1 module) | Yes (1 module) | No | No |
| 10-bit ADC | No | No | No | No | Yes (4 channels) |
| Operating Temperature | -40 °C to +85 °C (Industrial, I grade) | -40 °C to +85 °C | -40 °C to +125 °C (Extended, E grade) | -40 °C to +85 °C | -40 °C to +85 °C |
Key Differentiators
- Integrated EUART with internal EEPROM (vs PIC12F609-I/MD)
- No ADC, comparator instead (vs PIC12F615-I/MD)
- Industrial vs Extended temperature grade (vs PIC12F635-E/MD)
Design Notes
Solder the exposed thermal pad (EP) of the 8-pin DFN package to a grounded copper pour of at least 10 mm x 10 mm. The EP provides both the primary thermal path (improving power dissipation by ~30%) and mechanical solder-joint reliability. Place a 100 nF ceramic decoupling capacitor within 5 mm of the VDD pin (pin 8) and connect VSS (pin 5) directly to the ground plane with a via. Leave RA0/RA1 accessible on test points or a header for ICSP programming and in-circuit debugging - routing them through 0-ohm jumpers allows them to be isolated from application circuits during development.
The PIC12F635-I/MD supports the full 2.0 V to 5.5 V supply range, but the maximum CPU clock derates to 10 MHz below 4.5 V. If your design must run at full 20 MHz across the entire voltage range, add a voltage supervisor or use the internal Brown-Out Detect (BOD) configured for the 4.5 V threshold to prevent out-of-spec operation. Disable unused peripherals (ADC, EUART, comparators) via firmware to drop Sleep current below 1 µA - each disabled peripheral reduces quiescent current by several hundred nanoamperes. Use the internal 8 MHz oscillator with PLL to avoid the cost and BOM of an external crystal.
Estimated: The PIC12F635 does NOT include a 10-bit ADC - if your design reads analog sensors, choose PIC12F675 or PIC12F683 (same 8-pin footprint) instead. The MCLR pin (RA3) is enabled by default in configuration bits; if you tie it directly to VDD without enabling the internal weak pull-up, the part will not start. Configuration bits are FLASH-programmed and must be set correctly (watchdog timer disable, brown-out threshold, oscillator mode) before the first code execution. The ICSP interface uses RA0 (data) and RA1 (clock); these pins cannot be used as GPIO while a debugger is connected. Finally, the 1.75 KB Flash is partitioned as 1K x 14 instruction words - a single 14-bit word holds one PIC instruction, so a 2 KB C-compiler output will overflow.
Compliance Information
RoHS and lead-free per Microchip product page. The PIC12F635-I/MD is not AEC-Q100 qualified - automotive designs should select the PIC12F635-E/MD (extended temperature) variant, although E-grade is industrial-test rather than automotive-qualified. REACH compliance statement available on Microchip's product environmental compliance page.
