PIC12F635-E/SN - 8-bit MCU, 1.75KB Flash, 20MHz, 8-SOIC | Microchip
MPN: PIC12F635-E/SN ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.92 | $0.92 |
| 10 | $0.85 | $8.50 |
| 100 | $0.76 | $76.00 |
| 500 | $0.69 | $345.00 |
| 1,000 | $0.62 | $620.00 |
PIC12F635-E/SN Overview
An 8-bit microcontroller is a single-chip computer that processes data 8 bits at a time and typically integrates a CPU, program memory (Flash/ROM), data memory (SRAM), non-volatile storage (EEPROM), timers, communication peripherals, and I/O pins onto one silicon die. Within the broader taxonomy, 8-bit MCUs sit beneath 16-bit and 32-bit MCUs in processing capability, but lead in cost-effectiveness, deterministic interrupt response, and ultra-low power consumption, making them dominant in compact embedded designs. The PIC12F635 belongs to Microchip's PIC12 sub-family, which targets low pin count (8-14 pins) cost-sensitive applications where space, BOM cost, and battery life matter most.
Key features include a wide operating voltage range of 2.0V to 5.5V, an internal 4 MHz high-precision oscillator (factory calibrated to ±1%), 10-bit A/D converter with up to 4 input channels, an enhanced USART, an 8-bit/16-bit timer, and a hardware comparator. The nanoWatt technology provides multiple low-power modes (Run, Idle, Sleep) with standby currents as low as 50 nA typical, enabling multi-year battery life on small coin cells.
The PIC12F635 architecture uses a 14-bit wide instruction word with single-cycle execution except for branches, providing predictable timing critical for real-time control. Its enhanced mid-range core adds hardware multiply, larger stack, and prioritized interrupts versus baseline PIC devices, making it suitable for applications requiring deterministic response.
Typical applications include remote control transmitters, sensor signal conditioning, automotive body electronics, lighting controllers, RF tag readers, battery-powered consumer devices, and small appliance controls. The 8-pin footprint fits space-constrained PCB layouts while still providing enough peripherals for typical sensor-interface and actuator-control tasks.
When designing with this MCU, ensure the MCLR pin is pulled high through a 10 kΩ resistor for normal operation, place a 0.1 µF decoupling capacitor close to VDD, and configure unused I/O pins as outputs to minimize current draw. The internal oscillator eliminates external crystal cost but allows external crystal mode if higher frequency accuracy is needed.
This page synthesizes distributor pricing, parametric comparison, drop-in alternatives, and practical design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for PIC12F635-E/SN — 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-E/SN (same form factor and footprint) — differing in Package, Timers, Internal Oscillator, Operating Temperature, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12F635-I/SN
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F635T-I/SN
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.12 / Unit
View Datasheet →PIC12F675-I/SN
✅ Drop-In✓ In Stock
$0.74 / Unit
View Datasheet →PIC12F629-I/SN
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →PIC12F615-E/SN
✅ Drop-In✓ In Stock
$0.84 / Unit
View Datasheet →PIC12F635-E/SN Maximum Ratings & Electrical Characteristics
| Architecture | 8-bit PIC Mid-Range MCU |
| Program Memory (Flash) | 1.75 KB (1K x 14 words) |
| Data SRAM | 64 bytes |
| Data EEPROM | 128 bytes |
| CPU Speed (max) | 20 MHz |
| Instruction Width | 14 bits |
| Operating Voltage | 2.0 V to 5.5 V |
| I/O Pins | 5 GPIO + 1 input-only |
| Total Pin Count | 8 |
| ADC | 10-bit, 4 channels |
| Timers | 1 x 8-bit, 1 x 16-bit |
| Enhanced PWM | ECCP module |
| Communication | EUSART, SPI, I2C |
| Internal Oscillator | 4 MHz / 8 MHz selectable |
| Comparator | 1 internal analog comparator |
| Package | 8-SOIC (SN) 3.90 mm |
| Operating Temperature | -40 °C to +125 °C |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited floor life) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC12F635-E/SN Pin Configuration
| Pin 1 | VDD — Positive supply voltage (2.0V to 5.5V) |
| Pin 2 | GP5/T1CKI/OSC1/CLKIN — GPIO5 / Timer1 clock input / Oscillator input / External clock input |
| Pin 3 | GP4/T1G/OSC2/CLKOUT — GPIO4 / Timer1 gate / Oscillator output / Clock output |
| Pin 4 | GP3/MCLR/VPP — GPIO3 (input only) / Master Clear reset (active low) / Programming voltage |
| Pin 5 | GP2/AN2/T0CKI/INT/COUT/CCP1 — GPIO2 / ADC channel 2 / Timer0 clock / External interrupt / Comparator output / ECCP1 PWM output |
| Pin 6 | GP1/AN1/CIN-/VREF/ICSPCLK — GPIO1 / ADC channel 1 / Comparator inverting input / Voltage reference / ICSP clock |
| Pin 7 | GP0/AN0/CIN+/ICSPDAT/ULPWU — GPIO0 / ADC channel 0 / Comparator non-inverting input / ICSP data / Ultra-low-power wake-up |
| Pin 8 | VSS — Ground reference |
Typical Applications
PIC12F635-E/SN is suitable for 7 applications: Remote Control Transmitters, Battery-Powered Sensor Nodes, Automotive Body Electronics, LED Lighting Controllers, Small Appliance Controls, RF Tag and Transponder Readers, Industrial Control Modules.
Remote Control Transmitters
The PIC12F635-E/SN is well-suited for IR/RF remote control transmitters thanks to its nanoWatt low-power technology, internal oscillator, and small 8-SOIC footprint. Its EUSART peripheral supports direct connection to RF transmitter modules such as 433 MHz ASK/OOK devices, while the ECCP PWM module can drive an IR LED directly at 38 kHz carrier frequency. The wide 2.0-5.5 V input range allows direct operation from a single 3 V coin cell, with Sleep currents below 50 nA enabling multi-year battery life in intermittent-use remote applications. Engineers typically use GP2/CCP1 for the modulated IR output and GP0-1 for button matrix scanning, while the comparator monitors battery voltage for low-battery LED indication without waking the CPU.
Recommended
Battery-Powered Sensor Nodes
The PIC12F635-E/SN excels in battery-powered wireless sensor nodes where standby current, BOM size, and integrated analog peripherals determine design viability. The internal 4 MHz oscillator factory-calibrated to ±1% eliminates an external crystal, while the internal comparator wakes the MCU from Sleep on analog threshold crossings - a core-independent function that minimizes active CPU time and preserves battery life. The 10-bit ADC supports direct connection to thermistors, photocells, or potentiometers, and the wide 2.0-5.5 V supply range accepts unregulated lithium battery stacks. A typical sensor-node design averages 2-5 µA over the duty cycle, allowing a single CR2032 coin cell to power the node for 3-5 years in periodic-reporting applications.
Recommended
Automotive Body Electronics
The PIC12F635-E/SN operates across the full -40 °C to +125 °C automotive temperature range, making it suitable for under-hood and cabin body-electronics modules such as lighting controllers, door-lock actuators, seat-position sensors, and HVAC damper drivers. Its EUSART enables LIN-bus slave communication through an external transceiver, while the ECCP PWM module drives LED dimming or small DC motor control at frequencies up to 20 kHz. The 1.75 KB Flash stores calibration data and protocol stacks, and the 128-byte EEPROM retains user settings through battery disconnect events. Automotive designs typically add external ESD protection and reverse-battery diodes around the MCU, with the internal Brown-Out Reset (BOR) handling supply transients common in 12 V automotive rails.
Recommended
LED Lighting Controllers
The PIC12F635-E/SN provides an integrated solution for small LED lighting controllers - from decorative accent strips to indicator lamp drivers - by combining its ECCP PWM module, internal comparator, and nanoWatt low-power modes in a compact 8-SOIC package. The 20 MHz instruction rate allows smooth PWM dimming at frequencies above 200 Hz, eliminating visible flicker in RGB color-mixing applications. The internal comparator can monitor LED current through a sense resistor, providing over-current protection without external op-amps. Designs typically use GP2/CCP1 as the PWM output, GP0-1 for SPI-controlled RGB driver ICs, and the comparator input to detect LED open/short faults that latch the controller into a safe state.
Recommended
Small Appliance Controls
The PIC12F635-E/SN fits small household appliance control boards (coffee makers, blenders, air purifiers, fan controllers) where its 5 GPIO pins plus 1 input-only pin are sufficient for keypad scanning, relay drive, and indicator LED control. The 20 MHz instruction rate executes user-interface state machines with sub-millisecond response, while the internal EEPROM stores user preference settings across power cycles. The hardware comparator directly monitors AC mains zero-crossing for triac-based heater control, eliminating external zero-cross detection circuitry. Designers typically pair the MCU with a small triac driver, a 5 V LDO regulator, and a 4x4 keypad matrix, fitting the complete control board into 25 mm x 30 mm of PCB area at very low BOM cost.
Recommended
RF Tag and Transponder Readers
The PIC12F635-E/SN, in conjunction with the pin-compatible PIC16F639 family member that integrates a 125 kHz LF analog front-end, forms the basis of low-cost RFID reader modules used in access control, asset tracking, and animal identification. The PIC12F635 handles digital protocol processing, command framing, and host communication via EUSART, while an external LF antenna and front-end circuit connect to the MCU. The internal comparator monitors the demodulated RSSI signal for carrier-presence detection, and the ECCP PWM generates the LF carrier modulation. With its 1.75 KB Flash, the MCU can implement basic ISO 11784/11785 read protocols, while designers needing the full analog front-end migrate to PIC16F639 for integrated LF receiver hardware.
Recommended
Industrial Control Modules
The PIC12F635-E/SN's industrial -40 °C to +125 °C operating range and integrated EUSART, comparator, and 10-bit ADC make it a cost-effective choice for distributed industrial I/O modules such as digital input debouncers, simple closed-loop controllers, and signal-conditioning front-ends. Designers mount the MCU inside sensor housings or DIN-rail terminal blocks where the 8-SOIC footprint fits in tight spaces. The EUSART supports RS-485 communication through an external transceiver like the ADM3485, while the hardware comparator implements window-discriminator analog inputs without external op-amps. The nanoWait Sleep current under 50 nA lets modules remain powered from a shared 24 V rail without contributing meaningful quiescent load to the bus supply.
Recommended
Recommended Products Summary
Engineering reference data for PIC12F635-E/SN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12F635-I/SN | PIC12F675-I/SN | PIC12F629-I/SN | PIC12F615-E/SN |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-SOIC (SN) | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same | 8-SOIC (SN) - same |
| Program Memory (Flash) | 1.75 KB | 1.75 KB | 1.75 KB | 1.75 KB | 1.4 KB |
| CPU Speed (max) | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating Voltage | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| ADC | 10-bit, 4 channels | 10-bit, 4 channels | 10-bit, 4 channels | None | 10-bit, 4 channels |
| EUSART | Yes | Yes | No | No | No |
| Hardware Comparator | Yes | Yes | Yes | No | Yes |
| Operating Temperature | -40 °C to +125 °C (Extended) | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (Industrial) | -40 °C to +125 °C (Extended) |
| Unit Price (qty 1, USD) | $0.92 | $0.95 | $1.20 | $0.95 | $0.85 |
Key Differentiators
- Integrated EUSART and hardware comparator in 8-pin package (vs PIC12F629-I/SN)
- Extended -40 °C to +125 °C automotive temperature grade (vs PIC12F635-I/SN (Industrial))
- 1.75 KB Flash versus 1.4 KB Flash in PIC12F615 (vs PIC12F615-E/SN)
Design Notes
Place a 0.1 µF ceramic decoupling capacitor as close as possible to the VDD pin (pin 1) of the PIC12F635, with a trace length under 5 mm to suppress high-frequency switching noise. For designs with switching loads on the same supply, add a 10 µF tantalum or ceramic bulk capacitor near the MCU to handle transient current demands during ADC conversions and EEPROM writes. The internal 4 MHz oscillator draws roughly 2 mA active; use Sleep mode (50 nA typical) for duty-cycled battery applications to extend battery life.
The MCLR pin (pin 4) requires a 10 kΩ pull-up resistor to VDD for normal operation; do not leave it floating. For in-circuit serial programming (ICSP), add a 4.7 kΩ resistor in series with the ICSPCLK line (pin 6) and ICSPDAT line (pin 7) to isolate the programmer from the application circuit. Keep the ICSP connector traces short and away from switching signals. The 8-SOIC (SN) package is 3.90 mm wide; allow 0.5 mm clearance around the package for automated optical inspection.
Do not configure unused GPIO pins as analog inputs (they will draw current); instead, set them as outputs driving low or as digital inputs with the internal weak pull-up enabled. The GP3/MCLR pin is input-only and cannot be configured as an output. When using the internal comparator, disable the digital input buffer on the comparator pins to prevent unwanted digital switching noise; this is controlled by the CMCON register. The ADC reference voltage defaults to VDD; for high-precision measurements, use an external reference applied to the GP1/VREF pin.
Estimated: When using the EUSART at 20 MHz CPU clock, the maximum reliable baud rate is approximately 1.25 Mbaud. For long-distance RS-485 communication, lower the baud rate to 115200 or below to avoid signal integrity issues from cable capacitance. The internal 4 MHz oscillator has ±1% factory calibration but ±2% drift over temperature; use the FOSC<4:0> configuration bits to switch to an external crystal if higher frequency accuracy is needed for UART baud-rate stability.
Compliance Information
RoHS compliant and lead-free per Microchip product page. Not AEC-Q100 qualified - the part targets industrial/consumer markets, not automotive safety-critical applications.
