PIC16F639-E/SS - 8-bit 20MHz Flash MCU w/ KeeLoq Crypto | Microchip
MPN: PIC16F639-E/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.18 | $3.18 |
| 10 | $2.94 | $29.40 |
| 100 | $2.58 | $258.00 |
| 500 | $2.21 | $1,105.00 |
| 1,000 | $1.86 | $1,860.00 |
PIC16F639-E/SS Overview
A PIC microcontroller is a Harvard-architecture, RISC-based 8-bit MCU that executes single-word instructions in a single instruction cycle (except branches), giving it deterministic throughput for embedded control tasks. PIC MCUs sit inside the broader hierarchy: microcontroller (MCU) -> embedded processor -> semiconductor IC. The PIC16F639 belongs to the PIC16 family, characterized by 14-bit instruction words, 35 single-word instructions, and on-chip Flash program memory. The 'F' suffix indicates Flash-based (reprogrammable in-circuit), and the '639 denotes a member of the LF PIC family that bundles analog peripherals with the KeeLoq security engine.
Key features of the PIC16F639-E/SS include an integrated hardware KeeLoq-compatible cryptographic encoder for secure remote-keyless-entry (RKE) and rolling-code applications, a Programmable Low-Voltage Detect (PLVD) circuit, two on-chip analog comparators, an internal 8 MHz oscillator, and the nanoWatt power-management feature set with multiple sleep modes. The 11 I/O pins support digital I/O, analog comparator inputs, and peripheral functions. The device operates from 2.0 V to 3.6 V (per Microchipusa) and 4.5 V to 5.5 V (per Chipdig summary - two voltage ranges are reported by different sources; see _validation_note).
Architecture-wise, the PIC16F639 employs a 14-bit instruction word with a 35-instruction RISC core, an 8-level hardware stack, and direct/indirect addressing modes. The on-chip Flash allows in-circuit serial programming (ICSP) via two pins, eliminating external programming hardware during prototyping. The KeeLoq-compatible cryptographic module performs rolling-code encoding in hardware, drastically reducing the firmware burden for secure transmitter designs.
Typical applications include remote keyless entry (RKE) systems, automotive immobilizers, secure access controls, wireless security sensors, and low-power battery-operated remote controls. The 20-pin SSOP package and compact footprint also make the device suitable for small-form-factor industrial sensors and consumer electronics. Per Microchip, the -E temperature grade is the Extended (-40 C to +125 C) variant.
When designing with this part, note that the PIC16F639 uses ICSP pins (RB6/RB7) which are shared with general-purpose I/O - allocate them carefully if the firmware requires in-circuit programming access. The KeeLoq-compatible encoder requires a manufacturer-specific transmission protocol and code-format configuration that must be licensed and programmed at production time.
This page synthesizes distributor pricing, drop-in alternatives (same-brand PIC16F639-TI variants), and practical design notes not found in the manufacturer datasheet, helping engineers evaluate this device for secure low-power embedded designs.
Drop-in alternatives for PIC16F639-E/SS — 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 PIC16F639-E/SS (same form factor and footprint) — differing in Core Architecture, I/O Pins, Instruction Set.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F639-I/SS
✅ Drop-In✓ In Stock
$2.2 / Unit
View Datasheet →PIC16F639T-E/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F639T-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F639-E/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (14-bit instruction word) |
| Instruction Set | 35 single-word instructions |
| CPU Speed | 20 MHz (max) |
| Program Memory (Flash) | 3.5 KB (2K x 14 words) |
| RAM | 256 bytes |
| I/O Pins | 11 |
| Supply Voltage Range (low) | 2.0 V to 3.6 V (per Microchipusa summary) |
| Supply Voltage Range (high) | 4.5 V to 5.5 V (per Chipdig summary) |
| Operating Temperature (E grade) | -40 C to +125 C (Extended) |
| Cryptographic Module | KeeLoq-compatible hardware encoder |
| Analog Comparators | 2 |
| Low-Voltage Detect | Programmable (PLVD) |
| ICSP | In-Circuit Serial Programming (RB6/RB7) |
| Package | 20-pin SSOP (5.30 mm body) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC16F639-E/SS Pin Configuration
| Pin 1 | RA5 — Bidirectional I/O / analog comparator reference |
| Pin 2 | RA4 — Bidirectional I/O / Timer0 clock input |
| Pin 3 | RA3 — Bidirectional I/O / MCLR (Reset, active-low) |
| Pin 4 | RA2 — Bidirectional I/O / analog comparator input |
| Pin 5 | RA1 — Bidirectional I/O / analog comparator input |
| Pin 6 | RA0 — Bidirectional I/O / analog comparator input |
| Pin 7 | VSS — Ground reference |
| Pin 8 | VDD — Positive supply voltage |
| Pin 9 | OSC2 — Crystal/Resonator connection or digital I/O |
| Pin 10 | OSC1 — Crystal/Resonator connection or digital I/O |
| Pin 11 | RB7 — Bidirectional I/O / ICSP data |
| Pin 12 | RB6 — Bidirectional I/O / ICSP clock |
| Pin 13 | RB5 — Bidirectional I/O / KeeLoq-related I/O |
| Pin 14 | RB4 — Bidirectional I/O / KeeLoq-related I/O |
| Pin 15 | RB3 — Bidirectional I/O / KeeLoq-related I/O |
| Pin 16 | RB2 — Bidirectional I/O / KeeLoq-related I/O |
| Pin 17 | RB1 — Bidirectional I/O / KeeLoq-related I/O |
| Pin 18 | RB0 — Bidirectional I/O / KeeLoq-related I/O / interrupt |
| Pin 19 | VDD — Positive supply voltage (second VDD pin) |
| Pin 20 | VSS — Ground reference (second VSS pin) |
Typical Applications
PIC16F639-E/SS is suitable for 7 applications: Remote Keyless Entry (RKE) Transmitter, Automotive Immobilizer, Wireless Security Sensor Node, Garage Door Opener Remote, Industrial Remote Control Pendant, Access Control Keypad / Token, Smart Meter / Utility Tamper Detection.
Remote Keyless Entry (RKE) Transmitter
The PIC16F639-E/SS is purpose-built for handheld remote keyless entry transmitters thanks to its integrated KeeLoq-compatible hardware cryptographic encoder. The 3.5 KB Flash stores manufacturer key, serial number, and rolling-code counter; the 256-byte RAM handles button debounce and transmission framing. Operating at 20 MHz with 2.0-3.6 V supply from a single CR2032 cell, the device delivers a 200 ns instruction cycle while the nanoWatt sleep modes drop quiescent current to microamp levels between button presses. The 11 I/O pins support up to 4-5 button inputs plus an LED indicator and SAW/UHF transmitter enable, while ICSP on RB6/RB7 allows factory key provisioning without external programmer hardware. The Extended -40 C to +125 C temperature grade covers automotive cabin environments.
Recommended
Automotive Immobilizer
For automotive immobilizer systems the PIC16F639-E/SS provides the rolling-code authentication core that pairs a transponder in the key with the vehicle ECU. The KeeLoq-compatible encoder generates a unique transmission each insertion event; the on-chip PLVD monitors battery voltage to flag low-battery conditions to the user before lockout. The Extended -40 C to +125 C grade is mandatory for under-dash and steering-column installations where temperatures regularly exceed 85 C. With 20 MHz CPU throughput the MCU completes the authentication handshake in well under 100 ms, and the 20-SSOP package fits inside the key-head form factor alongside the LF coil interface circuitry.
Recommended
Wireless Security Sensor Node
In wireless door/window contact and PIR motion sensors the PIC16F639-E/SS combines low power consumption with secure transmission. The on-board analog comparators (2x) can directly interface to a PIR sensor amplifier output without external comparator ICs, while the Programmable Low-Voltage Detect (PLVD) issues a low-battery warning when the coin-cell drops below threshold. The 3.5 KB Flash accommodates sensor event logs and rolling-code transmission routines; the 256-byte RAM is sufficient for stack and temporary event buffering. nanoWatt sleep modes drop quiescent current to single-digit microamps, enabling multi-year battery life on a single CR2032 cell.
Recommended
Garage Door Opener Remote
Garage door opener remotes benefit from the PIC16F639-E/SS rolling-code security to prevent code-grabbing replay attacks. The 3.5 KB Flash stores manufacturer key plus learn-mode routine; 11 I/O pins support 2-3 buttons (open/close/light), a transmit-enable line to the 315/433 MHz SAW transmitter, and a learn-mode LED indicator. 20 MHz execution ensures the rolling-code algorithm runs within the transmit window before the RF stage is keyed on, reducing average current draw. The Extended -40 C to +125 C temperature grade covers garage environments where summer heat can push inside-vehicle temperatures above 70 C.
Recommended
Industrial Remote Control Pendant
For overhead crane controls, hoist remotes, and other industrial pendant stations the PIC16F639-E/SS Extended temperature rating is essential. The on-chip KeeLoq-compatible encoder prevents accidental or malicious actuation by ensuring every transmission is uniquely encoded. The two analog comparators can monitor battery voltage and an emergency-stop input without external circuitry. The 20-pin SSOP package with 11 I/O pins supports up to 6 motion-control buttons plus an E-stop line, and the nanoWatt sleep modes extend battery life between shifts.
Recommended
Access Control Keypad / Token
For PIN-pad entry systems and proximity-token authenticators the PIC16F639-E/SS provides hardware-accelerated rolling-code encoding that is far more secure than software-only implementations. The 3.5 KB Flash stores the token ID, rolling counter, and authentication routine; the 256-byte RAM handles keypad scan buffering. 11 I/O pins support a 4x4 matrix keypad scan or 8 capacitive-touch inputs, plus status LED and buzzer drive. Operating from 2.0-3.6 V the device runs from battery backup during power outages, maintaining secure access even when the host controller is offline.
Recommended
Smart Meter / Utility Tamper Detection
Utility smart meters use the PIC16F639-E/SS as a low-power cryptographic co-processor that detects tamper events (magnetic field, cover removal, reverse current) and securely transmits them back to the utility. The two on-chip comparators monitor the meter's Hall-effect sensor and tamper switches directly; the PLVD detects brownout conditions and saves state to Flash. The KeeLoq-compatible encoder ensures the tamper alert cannot be spoofed by an attacker. The Extended -40 C to +125 C temperature grade is required for outdoor meter installations in extreme climates.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F639-E/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F639-I/SS | PIC16F639T-E/SS | PIC16F639T-I/SS |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-SSOP | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same |
| Temperature Grade | Extended (-40C to +125C) | Industrial (-40C to +85C) | Extended (-40C to +125C) | Industrial (-40C to +85C) |
| Packaging | Tube | Tube | Tape and Reel | Tape and Reel |
| Flash Memory | 3.5 KB | 3.5 KB | 3.5 KB | 3.5 KB |
| RAM | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| CPU Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| KeeLoq Crypto Module | Yes (hardware) | Yes (hardware) | Yes (hardware) | Yes (hardware) |
| Lifecycle Status | Active | Active | Active | Active |
Key Differentiators
- Integrated KeeLoq-compatible hardware cryptographic encoder (vs PIC16F628A-I/SS)
- Extended -40 C to +125 C temperature grade for harsh environments (vs PIC16F639-I/SS)
- On-chip analog comparators and PLVD eliminate external components (vs Generic 8-bit MCU without comparators)
Design Notes
The PIC16F639-E/SS operates from 2.0 V to 3.6 V per the Microchipusa summary (note: one third-party source lists 4.5-5.5 V - verify with the official datasheet document 41249E before design). For CR2032 coin-cell applications the nanoWatt sleep modes drop quiescent current below 1 uA; however, peak TX current during a KeeLoq transmission can briefly reach 10 mA on the RF stage, so add a 100 nF decoupling cap adjacent to VDD (pin 8) and a 10 uF bulk cap on the battery terminal.
Estimated: keep the SSOP-20 trace from MCLR (RA3, pin 3) short and away from RF traces to avoid spurious resets. The ICSP pins RB6/RB7 (pins 11/12) must be accessible on the PCB for in-circuit programming - do not load them with heavy capacitance. Place the decoupling capacitor (100 nF X7R) within 3 mm of VDD pin 8, and ensure both VSS pins (7 and 20) are tied to a continuous ground plane for thermal and electrical stability.
The MCLR pin (RA3) is shared with general-purpose I/O - if you enable the internal MCLR (default configuration), the pin cannot be used as GPIO without configuration-word changes. Also note that KeeLoq transmission encoding requires a manufacturer-specific transmission format and serial number that must be programmed at production time using a Microchip-approved programmer; do not assume generic rolling-code libraries will work without the proper Microchip KeeLoq toolkit.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - the Extended temperature grade is specified for the silicon, but the part is not formally AEC-Q100 certified. For full AEC-Q100 automotive qualification contact Microchip directly.
