PIC16F636-I/SL - 8-Bit MCU, 3.5KB Flash, 20MHz | Microchip
MPN: PIC16F636-I/SL ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.91 | $1.91 |
| 10 | $1.72 | $17.20 |
| 100 | $1.53 | $153.00 |
| 500 | $1.38 | $690.00 |
| 1,000 | $1.27 | $1,270.00 |
PIC16F636-I/SL Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, memory, and peripherals on one die. The PIC16F636 belongs to the broad PIC family -> mid-range 8-bit MCU category -> CMOS Flash-based MCU, distinguished from MIPS-, ARM-, or RISC-V-based MCUs by its Harvard RISC architecture and 14-bit instruction word. Its place in the system hierarchy is typically as the brain of small embedded control loops where deterministic instruction timing and low current draw (NanoWatt technology) matter more than raw CPU throughput.
Key features include a 13-bit program counter capable of addressing 8K x 14 program space, DC-20 MHz clock speed (200 ns instruction cycle), 5 wake-up sources from Sleep, and an integrated KeeLoq-compatible Cryptographic Module for secure remote-keyless-entry applications. The 2 on-chip comparators with programmable hysteresis and dedicated reference simplify analog front-ends without external op-amps. Programmable code protection and ICD/debug support make it friendly for both secure production deployment and bench development.
The PIC16F636 uses a Harvard architecture with separate program and data buses, allowing instruction fetch and operand read in a single cycle except for branches. Its NanoWatt technology yields sub-µA Sleep current with multiple wake-up options (interrupt-on-change, comparators, timers, watchdog), suited to battery-powered duty-cycled applications. Internal RC oscillator options (8 MHz, 32 kHz, 31 kHz LF) reduce BOM cost and board area by eliminating external crystals in non-precision timing designs.
Typical applications include remote keyless entry (RKE) transmitters, security alarm panels, smoke and CO detectors, automotive body controllers, low-end remote sensors, and small appliance controls. The integrated KeeLoq cipher suits rolling-code secure wireless links where a discrete cryptographic IC would inflate BOM cost and PCB area.
When designing with this part, verify the package derating at high temperatures and confirm that the chosen debugger (ICD3, PICkit 3/4, MPLAB Snap) header layout matches the MCLR/PGD/PGC pin assignments. The /SL suffix indicates industrial temperature grade (-40C to +85C) and SOIC-14 tube packaging.
This page synthesizes distributor pricing, drop-in alternative MPNs, and practical design notes not found on any single manufacturer or distributor page.
Drop-in alternatives for PIC16F636-I/SL — 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 PIC16F636-I/SL (same form factor and footprint) — differing in Operating Temperature, Package, Comparators, ADC, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F639-I/SL
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC12F635-I/SN
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC16F685-I/SO
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.68 / Unit
View Datasheet →PIC16F18323-I/P
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PIC16F636-I/SL Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 (8-bit RISC, Harvard) |
| Program Memory (Flash) | 3.5 KB (2K x 14) |
| RAM | 128 bytes |
| Data EEPROM | 256 bytes |
| Maximum CPU Speed | 20 MHz |
| Instruction Count | 35 instructions |
| I/O Pins | 12 |
| Comparators | 2 (with programmable hysteresis) |
| Timers | 5 (depending on configuration) |
| Supply Voltage | 2.0 V to 5.5 V |
| Operating Temperature | -40C to +85C (Industrial, -I suffix) |
| Package | 14-SOIC (SL, 3.90 mm body) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited floor life) |
| RoHS Status | Compliant (lead-free) |
| Cryptographic Module | KeeLoq-compatible |
| PLVD | Programmable Low-Voltage Detect |
| Technology | NanoWatt (low-power) |
PIC16F636-I/SL Pin Configuration
| Pin 1 | VDD — Positive supply voltage (2.0V to 5.5V) |
| Pin 2 | RA5 — Bidirectional I/O with KeeLoq TX clock option |
| Pin 3 | RA4 — Bidirectional I/O / T0CKI (Timer0 clock input) |
| Pin 4 | RA3/MCLR/VPP — I/O or Master Clear (reset) / ICSP programming voltage |
| Pin 5 | RC5 — Bidirectional I/O / CCP1 (Capture/Compare/PWM) |
| Pin 6 | RC4 — Bidirectional I/O / C2OUT (Comparator 2 output) |
| Pin 7 | RC3 — Bidirectional I/O / analog channel |
| Pin 8 | RC2 — Bidirectional I/O / analog channel |
| Pin 9 | RC1 — Bidirectional I/O / analog channel |
| Pin 10 | RC0 — Bidirectional I/O / analog channel |
| Pin 11 | RA2 — Bidirectional I/O / analog channel |
| Pin 12 | RA1 — Bidirectional I/O / C1OUT (Comparator 1 output) |
| Pin 13 | RA0 — Bidirectional I/O / ICSP clock / analog channel |
| Pin 14 | VSS — Ground reference |
Typical Applications
PIC16F636-I/SL is suitable for 7 applications: Remote Keyless Entry (RKE) Transmitters, Smoke and CO Detectors, Security Alarm Panels, Small Appliance Control Boards, Automotive Body Controllers, Wireless Sensor Nodes (Battery-Powered), Consumer Remote Controls.
Remote Keyless Entry (RKE) Transmitters
The PIC16F636-I/SL is purpose-built for remote keyless entry and garage-door opener transmitters thanks to its on-chip KeeLoq-compatible Cryptographic Module and NanoWatt Sleep current below 1 µA. The cipher generates rolling codes that defeat simple replay attacks without external crypto ICs, while NanoWatt technology lets the keyfob operate for multiple years on a single CR2032 coin cell. At 20 MHz maximum clock, the device delivers enough headroom to drive Manchester-coded UHF transmitters (315/433/868 MHz SAW-based) and decode with interrupt-on-change. Compare it favorably against discrete encoder + MCU designs, which add BOM cost and PCB area to small wearable keyfobs.
Recommended
Smoke and CO Detectors
Battery-powered smoke and CO detectors benefit from the PIC16F636-I/SL NanoWatt Sleep current (sub-µA) and dual on-chip comparators that simultaneously monitor an ionization chamber and an electrochemical CO sensor. The programmable low-voltage detect (PLVD) ensures end-of-life chirp signalling when a 9 V battery drops below threshold, while the 256 bytes of EEPROM store 10-year cumulative sensor history and the device calibration constants. The 35-instruction RISC core executes the long-cycle ionization chamber read with deterministic timing, and the 12 I/O lines drive LED indicators, buzzer PWM, and the sensor drive circuits.
Recommended
Security Alarm Panels
The PIC16F636-I/SL fits small 4- to 8-zone hardwired alarm panels where 12 I/O lines suffice for door/window sensors, keypad scanning, and siren drive, while its 3.5 KB Flash accommodates zone-identifying custom messages, LED patterns, and EEPROM logs of arm/disarm events. Programmable code protection defends installer codes and the customer's security PIN from extraction, and 5 timer/counters drive piezo-keypad scanning, RTC roll-over, and watchdog. The KeeLoq cipher enables paired wireless keyfob support so the same MCU handles both wired and wireless sensors in one BOM.
Recommended
Small Appliance Control Boards
Microwave ovens, induction cooktops, coffee machines, and bread makers use the PIC16F636-I/SL because its 2 comparators drive Zero-Cross Detection on the AC line, its 5 timers control relay-switched heater and motor cycles, and its Flash memory holds feature differentiation firmware. Compared to mask-ROM ASIC solutions, the PIC16F636 lets mid-volume appliance manufacturers update firmware for energy-compliance certifications without re-spinning silicon, halving time to market and avoiding factory line-tooling costs. Industrial temperature grade handles the kitchen ambient environment.
Recommended
Automotive Body Controllers
Inside automotive body and convenience modules such as door locks, mirror positioners, seat heaters, and climate-control subsystems, the PIC16F636-I/SL delivers KeeLoq-grade encryption for paired keyless systems while driving the comparators, timers, and PWM outputs that control brushed DC actuators. Automotive OEM suppliers often use this part for tier-2 retrofit accessories where an integrated cipher is mandatory. Designers pair it with LIN or CAN transceivers for body-network wiring, though stricter AEC-Q100 projects usually migrate to the PIC16F15324 extended family.
Recommended
Wireless Sensor Nodes (Battery-Powered)
Battery-powered wireless sensor nodes (PIR detectors, glass-break sensors, temperature loggers) leverage the PIC16F636-I/SL NanoWatt Sleep currents to extend coin-cell operational life beyond 5 years. The 2 internal comparators handle low-side analog-event detection without waking the core for every threshold check, and the interrupt-on-change wakes the MCU only when a sensor transitions. The KeeLoq cipher safeguards mesh-network pairing codes against eavesdropping while the Cortex-class footprints would over-shoot BOM and current targets for this node class.
Recommended
Consumer Remote Controls
Consumer universal-remote controls (TVs, set-top boxes, streaming devices, AC units) frequently use the PIC16F636-I/SL because its on-chip KeeLoq cipher supports many manufacturer IR-protocol variants with a single firmware image. The NanoWatt sleep current lets the remote run for years on two AAA cells, while 12 I/O lines directly drive the IR emitter, RGB status LED, key matrix, and battery-monitoring ADC channel through PLVD. Pre-loaded firmware in the 3.5 KB Flash handles device-pairing codes, the 256-byte EEPROM stores learned-IR codes, and the 5 timers execute precise IR carrier-burst timing down to tens of microseconds.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F636-I/SL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F639-I/SL | PIC12F635-I/SN | PIC16F685-I/SO | PIC16F18323-I/P |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 14-SOIC (SL) | 14-SOIC (SL) - same | 8-SOIC (SN) - different footprint | 20-SOIC (SO) - different footprint | 14-PDIP (P) - different footprint |
| Flash Memory | 3.5 KB | 3.5 KB | 1.75 KB | 7 KB | 7 KB |
| Maximum Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 32 MHz |
| RAM | 128 bytes | 128 bytes | 64 bytes | 256 bytes | 256 bytes |
| EEPROM | 256 bytes | 256 bytes | 64 bytes | 256 bytes | 256 bytes |
| I/O Pins | 12 | 12 | 6 | 18 | 12 |
| Integrated Cryptographic Module | KeeLoq-compatible (yes) | KeeLoq-compatible (yes) | KeeLoq-compatible (yes) | No | No (firmware-based AES optional) |
| Supply 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 | 1.8 V to 5.5 V |
| Unit Price (qty 1, as of 2026-10-09) | $1.91 | $1.97 | $1.45 | $2.10 | $1.32 |
Key Differentiators
- On-chip KeeLoq Cryptographic Module (vs PIC16F685-I/SO)
- Larger Flash for richer feature sets (vs PIC12F635-I/SN)
- Newer PIC16F18323 offers higher core speed (vs PIC16F18323-I/P)
Design Notes
The PIC16F636 supports operating voltages from 2.0 V to 5.5 V but its NanoWatt Sleep current is specified below 1 µA at 3 V VDD. For best battery life in keyfob-style applications, regulate the supply with an LDO of no more than 50 µA quiescent (such as MCP1700 or XC6206) and place a 100 nF decoupling capacitor directly adjacent to VDD pin 1. Avoid high-Iq switching regulators in power-rail-sleep designs because their quiescent losses outweigh the MCU's consumption.
The MCLR/RA3 pin on this part is shared with the ICSP programming voltage input (VPP). Connect a 10 kΩ pull-up on MCLR to VDD so the device boots normally, while ensuring the ICSP programming header placement keeps the MCLR/PGD/PGC traces short and isolated from switching RF signals to prevent programming failures. Connect only the recommended 4.7 kΩ-10 kΩ series resistor on the MCLR/VPP line; values higher than 47 kΩ cause programming voltage margin failures.
Route the ICSP/ICDD traces (MCLR, PGD, PGC) together in a dedicated signal group and place the in-circuit-debug connector at the PCB edge for clean probe contact. Keep the COMPARATOR analog inputs (RA0-RA2, RC0-RC2) physically separated from PWM or high-frequency digital outputs (RC3-C5) to minimize digital coupling into the comparator stages. The SOIC-14 land pattern requires 1.27 mm pin pitch and standard 0.4 mm lead width, compatible with nearly all 14-SOIC footprints.
When using the on-chip comparators for low-side analog sensing, place a guard ring of ground (GND) traces around the comparator input pins to suppress digital switching noise. Reference the in-package VREF source rather than external diode-referenced strings when stability over 0.1% is required at room temperature. The 6.8 kΩ-50 kΩ analog-source impedance envelope is recommended to keep the comparator and ADC sampling time within datasheet limits.
Compliance Information
RoHS compliant per /SL suffix (lead-free matte-tin plating). Not AEC-Q100 qualified; for automotive engine-bay or under-hood designs, use AEC-Q100-graded parts such as PIC16F15324 series or PIC18F K-level.
