PIC12F635-E/P - 8-bit Flash MCU, 1.75KB, 6 I/O, 20MHz | Microchip
MPN: PIC12F635-E/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.26 | $2.26 |
| 10 | $2.02 | $20.20 |
| 100 | $1.78 | $178.00 |
| 500 | $1.55 | $775.00 |
| 1,000 | $1.38 | $1,380.00 |
PIC12F635-E/P Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, I/O peripherals, and often non-volatile EEPROM into one package. Within the broader taxonomy, an MCU sits below microprocessor (MPU) and above logic ICs, falling inside the integrated circuit category. Microchip's PIC architecture is a RISC-style design with only 35 single-word instructions and 200 ns instruction execution, making the PIC12F635 both powerful and easy to program in assembly or C.
Key features include nanoWatt Technology for ultra-low-power operation with multiple sleep modes and dynamic switching of peripheral clocks. On-chip peripherals include an 8-bit timer/counter, an enhanced 16-bit timer, a comparator module, a 10-bit ADC (not present on all variants - verify with datasheet), and an internal 8 MHz oscillator. The 'E' suffix denotes the extended industrial temperature range (-40C to +125C), while the 'P' suffix indicates the PDIP-8 package.
The device operates from 4.5V to 5.5V, supports in-circuit serial programming (ICSP) via two pins, and provides hardware fail-safe clock monitor functionality. Its internal oscillator architecture reduces external component count, making the PIC12F635-E/P suitable for space-constrained designs where minimal BOM is critical.
Typical applications include remote controls, sensor interfaces, battery-powered consumer devices, security and alarm panels, white-goods user-interface modules, low-end motor control loops, and LED driver controllers. The six I/O pins can be configured for analog input, digital I/O, or peripheral functions.
When designing with this MCU, ensure the supply rail stays within 4.5V to 5.5V. Use decoupling capacitors (100 nF and 10 uF) close to VDD/VSS, and follow Microchip's ICSP pin usage guidelines if in-circuit programming is required during production testing.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, giving engineers a single reference for selecting and sourcing the PIC12F635-E/P.
Drop-in alternatives for PIC12F635-E/P — 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/P (same form factor and footprint) — differing in Comparators, Package, Timers, MSL Level, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC12F635-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC12F635-E/MF
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →PIC12F629-E/P
✅ Drop-In✓ In Stock
$1.2 / Unit
View Datasheet →PIC12F675-E/P
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC12F683-E/P
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC12F615-E/P
✅ Drop-In✓ In Stock
$0.74 / Unit
View Datasheet →PIC12F617-E/P
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →PIC12F635-E/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory (Flash) | 1.75 KB (1K x 14) |
| RAM | 64 bytes |
| EEPROM | 128 bytes |
| Maximum Clock Speed | 20 MHz |
| I/O Pins | 6 |
| Supply Voltage (VDD) | 4.5 V to 5.5 V |
| Operating Temperature Range | -40 C to +125 C (E = Extended) |
| Package Type | 8-PDIP (Through-Hole, 0.300 inch / 7.62 mm) |
| Instruction Set | 35 single-word instructions |
| Instruction Execution Time | 200 ns @ 20 MHz |
| On-chip Oscillator | 8 MHz internal |
| Timers | 1 x 8-bit, 1 x 16-bit |
| Comparators | Yes |
| ICSP (In-Circuit Serial Programming) | Yes |
| Power-Saving Modes | nanoWatt Technology (multiple sleep modes) |
| RoHS Status | Compliant |
| MSL Level | 1 (not moisture-sensitive for PDIP) |
PIC12F635-E/P Pin Configuration
| Pin 1 | VDD — Positive supply voltage (4.5V to 5.5V) |
| Pin 2 | GP5/T1CKI/OSC1/CLKIN — GPIO port bit 5 / Timer1 clock input / Oscillator input / external clock input |
| Pin 3 | GP4/AN3/T1G/OSC2/CLKOUT — GPIO port bit 4 / Analog input 3 / Timer1 gate / Oscillator output / clock output |
| Pin 4 | GP3/MCLR/VPP — GPIO port bit 3 (input only) / Master Clear reset (active low) / programming voltage |
| Pin 5 | GP2/AN2/T0CKI/INT/COUT — GPIO port bit 2 / Analog input 2 / Timer0 clock input / external interrupt / comparator output |
| Pin 6 | GP1/AN1/CIN-/ICSPCLK — GPIO port bit 1 / Analog input 1 / comparator inverting input / ICSP clock |
| Pin 7 | GP0/AN0/CIN+/ICSPDAT — GPIO port bit 0 / Analog input 0 / comparator non-inverting input / ICSP data |
| Pin 8 | VSS — Ground reference |
Typical Applications
PIC12F635-E/P is suitable for 7 applications: Remote Control Transmitter, Battery-Powered Sensor Node, Security Alarm Panel Auxiliary, White Goods User Interface, LED Driver Controller, Automotive Accessory Module, Industrial Control Loop.
Remote Control Transmitter
The PIC12F635-E/P fits remote control transmitters because its 1.75 KB Flash comfortably holds fixed-key IR protocols (RC5, NEC, SIRC), 128 bytes of EEPROM preserves learned-key codes across battery swaps, and nanoWatt sleep mode drops quiescent current below 1 uA so a coin cell can last years. Six I/O drive the matrix keyboard and PWM-modulated IR LED; the on-chip comparator wakes the MCU from sleep on a key press. Compared with a discrete encoder IC, this part integrates protocol stack, EEPROM-backed memory, and watchdog in one 8-PDIP device, reducing BOM by 4-6 parts and PCB area by roughly 30 percent. This application matches the part's small memory, low-pin-count architecture and ultra-low-power capability.
Recommended
Battery-Powered Sensor Node
Wireless or wired sensor nodes benefit from the PIC12F635-E/P's nanoWatt Technology, which lets the core run below 100 nA in sleep and wake on comparator or timer interrupt. Six I/O handle analog sensor input, digital interrupt, and UART- or PWM-based data transmission; 1.75 KB Flash accommodates a small state machine plus calibration table. Compared to a discrete comparator + timer + MCU architecture, this part integrates 3-4 functions in one chip, cutting quiescent current roughly 40 percent and BOM cost 25 percent. Industrial-grade -E temperature rating suits outdoor or HVAC-mounted nodes. This application directly leverages the device's low-power sleep modes and on-chip peripherals.
Recommended
Security Alarm Panel Auxiliary
Security and alarm systems use the PIC12F635-E/P as a low-pin-count auxiliary controller for individual zones or as a loop expander on a main panel. The on-chip comparator thresholds analog sensor signals (PIR, smoke, glass-break), the 16-bit timer drives precise loop polling at 10 ms intervals, and EEPROM stores calibration constants and zone ID. Compared with a dedicated analog ASIC, this MCU is reprogrammable per zone, reducing SKU count by 5-10x. The 8-PDIP package is easy to hand-solder or wave-solder during panel assembly. This application fits the part's small footprint, comparator, and EEPROM-backed non-volatile storage.
Recommended
White Goods User Interface
Washing machines, dishwashers, and microwave ovens embed PIC12F635-E/P-style MCUs to scan the keypad, drive the LED/LCD indicator, and monitor door interlocks. Six I/O can matrix a 3x3 keypad plus a buzzer; the 8-bit timer debounces keys in software; EEPROM stores user presets (cycle, delay start) across power cycles. Compared with a discrete logic-IC solution, this part integrates scanning, beeping, and non-volatile memory in one chip, cutting PCB area roughly 35 percent. Industrial -40 C to +125 C rating handles the thermal environment behind a control panel. This application leverages the MCU's general-purpose I/O, timers, and small EEPROM.
Recommended
LED Driver Controller
LED strips, signage, and architectural lighting embed the PIC12F635-E/P as the pattern-generation brain. The 8-bit PWM channel (via the CCP module or software) drives MOSFET gate drivers at up to several kHz, while the 16-bit timer sets the frame period. NanoWatt sleep between updates lets battery-powered LED wearables run for weeks. Six I/O can also drive dot-correction EEPROMs over I2C bit-bang. Compared to a 555-timer or pure-logic LED controller, this MCU offers programmable patterns, brightness curves, and DMX-style dimming at negligible BOM cost. This application fits the part's timers, PWM capability, and low-power operation.
Recommended
Automotive Accessory Module
The PIC12F635-E/P's -40 C to +125 C extended temperature range and 8-PDIP form factor make it a fit for aftermarket automotive accessories such as auxiliary light controllers, alarm LED flashers, and trailer wiring modules. Six I/O drive relays and sense inputs (ignition, brake, reverse), EEPROM stores user configuration (mode, timing), and the on-chip comparator monitors battery voltage for low-voltage cutoff. Note: this is an industrial-grade -E variant, not AEC-Q100 qualified; for OEM automotive designs, select a Q-graded PIC12F part instead. Compared to a discrete 555-based flasher, this MCU offers programmable timing patterns in one IC.
Recommended
Industrial Control Loop
Small industrial controllers such as pump timers, valve sequencers, and conveyor interlocks use the PIC12F635-E/P for its deterministic 200 ns instruction cycle and EEPROM-backed setpoint storage. Six I/O drive solenoid drivers and read limit switches; the 16-bit timer enables precise interval timing; the watchdog timer prevents lockup in unattended installations. Compared with a PLC sub-module, this MCU delivers similar deterministic behavior at roughly 10 percent the cost and one-tenth the PCB area. The extended temperature grade supports cabinet-mounted installations near motors or heaters. This application fits the part's deterministic core, watchdog, and small footprint.
Recommended
Recommended Products Summary
Engineering reference data for PIC12F635-E/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC12F629-E/P | PIC12F675-E/P | PIC12F683-E/P | PIC12F615-E/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 8-PDIP (0.300 inch) | 8-PDIP (0.300 inch) - same | 8-PDIP (0.300 inch) - same | 8-PDIP (0.300 inch) - same | 8-PDIP (0.300 inch) - same |
| Program Memory (Flash) | 1.75 KB | 1.75 KB | 1.75 KB | 2 KB | 1 KB |
| RAM | 64 B | 64 B | 64 B | 256 B | 32 B |
| EEPROM | 128 B | 64 B | 128 B | 256 B | 64 B |
| Maximum Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| I/O Pins | 6 | 6 | 6 | 6 | 6 |
| Comparator | Yes | No | Yes | Yes | Yes |
| PWM | No (software PWM only) | No | Yes (1 channel) | Yes (1 channel) | Yes (enhanced PWM) |
| Supply Voltage | 4.5 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 |
| Operating Temperature | -40 C to +125 C (Extended) | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C |
Key Differentiators
- Higher EEPROM capacity than closest PIC12F variant (vs PIC12F629-E/P)
- Lower cost than functional-superset parts with ADC (vs PIC12F675-E/P)
- Extended temperature range as standard (vs PIC12F635-I/P)
Design Notes
Place a 100 nF decoupling capacitor as close as possible between VDD (pin 1) and VSS (pin 8), and add a bulk 10 uF tantalum or ceramic on the same supply rail within 25 mm. The PIC12F635-E/P draws peak currents up to 10 mA during Flash programming; insufficient decoupling can cause brown-out resets during ICSP. The device operates from 4.5V to 5.5V - if your rail is 3.3V, choose a PIC12F variant with the F suffix or PIC12F1840 instead.
Pin 4 (GP3/MCLR/VPP) is shared between GPIO, reset, and programming voltage. If MCLR is enabled in configuration bits, the pin cannot be used as a general-purpose input without an external pull-up. For designs that need GP3 as an input, disable the MCLR function in the config word and add an internal weak pull-up. Failing to follow this is the single most common reason PIC12F prototypes do not program or reset unexpectedly.
Keep the ICSP clock and data traces (GP1 and GP0) away from high-frequency switching nodes such as relay coils or PWM-driven MOSFETs. Recommended trace length under 50 mm with no parallel routing next to noisy signals. The ICSP interface is sensitive to capacitive loading above 30 pF, which can be exceeded if long cables or headers are used in production programming fixtures.
When using the analog inputs (AN0-AN3 on GP0, GP1, GP2, GP4), configure the I/O as analog via the ANSEL register to disable the digital input buffer; otherwise leakage from the digital gate can corrupt ADC readings by 1-2 LSB. Add a 100 nF ceramic across each analog input if the source impedance exceeds 10 kohm, per Microchip's analog design guidelines.
Estimated: at 20 MHz clock and 5.5 V supply with all peripherals active, the PIC12F635-E/P core dissipation is roughly 25 mW. In the PDIP-8 package with theta_JA near 100 C/W, junction temperature rise above ambient is about 2.5 C - well within the -40 C to +125 C rating. For industrial designs near the upper temperature limit, derate clock speed below 10 MHz to stay comfortably inside the safe operating area.
Compliance Information
RoHS and REACH compliant per Microchip product declaration. The -E suffix denotes extended industrial temperature grade (-40 C to +125 C), not AEC-Q100 automotive qualification - select a Q-suffix PIC12F variant for OEM automotive designs
