PIC16F639-E/SO - 8-Bit PIC MCU w/ KeeLoq, 3.5KB Flash | Microchip
MPN: PIC16F639-E/SO β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.15 | $315.00 |
| 500 | $2.78 | $1,390.00 |
| 1,000 | $2.45 | $2,450.00 |
PIC16F639-E/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, RAM, non-volatile program memory, and peripheral interfaces on one die. Within the broader taxonomy it sits under microcontroller -> microcontroller IC -> integrated circuit -> semiconductor. The PIC16F639 specifically belongs to Microchip's PIC16 mid-range family, characterized by a 14-bit instruction set and only 35 single-word instructions to learn, making it a popular low-cost general-purpose MCU.
Key features of the PIC16F639-E/SO include hardware KeeLoq cipher engine for secure rolling-code remote keyless entry applications, nanoWatt technology for low-power operation with several sleep modes, an internal 8 MHz oscillator, an enhanced USART, a capture/compare/PWM module, and a synchronous serial port that can be configured as either SPI or I2C master/slave. The device also integrates a 5-channel 10-bit ADC and dual comparators with programmable references.
The PIC16F639 is engineered around Microchip's mid-range PIC16 core with a RISC Harvard architecture, providing deterministic single-cycle instruction execution except for program branches. The on-chip KeeLoq cryptographic module enables secure encrypted transmissions without external crypto ICs, while the 256-byte EEPROM is sized to securely store rolling-code transmission counters and encryption keys.
Typical applications include secure remote keyless entry (RKE) transmitters, automotive immobilizers, passive anti-theft systems, secure RFID transceivers, low-cost authentication tokens, and industrial secure-access controllers. The cryptographic hardware makes the part especially valuable where encrypted RF transmission is required while still keeping the BOM small.
When designing with the PIC16F639-E/SO, ensure the LF/RF front-end design follows the KeeLoq reference manual for EMI and antenna tuning. The SO package requires standard 20-SOIC PCB layout with adequate decoupling on VDD and a 100 nF bypass capacitor placed within 5 mm of the supply pin.
This page synthesizes distributor pricing, drop-in package-compatible alternatives, and practical design notes not found in the manufacturer datasheet alone, optimized for engineers sourcing the PIC16F639-E/SO for secure low-power embedded designs.
Drop-in alternatives for PIC16F639-E/SO β 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/SO (same form factor and footprint) β differing in ADC, Comparators, Core Architecture, I/O Pins, Operating Temperature.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16F639-I/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16F639T-I/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16F636-I/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16F636-E/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16F631-I/SO
β Drop-Inβ In Stock
$1.28 / Unit
View Datasheet βPIC16F639-E/SO Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Core Architecture | PIC16 (mid-range, 14-bit instructions) |
| Program Memory (Flash) | 3.5 KB (2K x 14) |
| RAM | 128 bytes |
| EEPROM | 256 bytes |
| Maximum Clock Frequency | 20 MHz |
| Supply Voltage (VDD) | 2.0 V to 5.5 V |
| I/O Pins | 11 |
| ADC | 10-bit, 5 channels |
| Comparators | 2 (with programmable reference) |
| Cryptographic Module | KeeLoq-compatible hardware cipher |
| PLVD (Programmable Low-Voltage Detect) | Yes |
| Communication Peripherals | Enhanced USART, SSP (SPI / I2C), CCP |
| Timers | Timer0, Timer1, Timer2 |
| Oscillator Options | Internal 8 MHz, external, LP/HS/XT/RC modes |
| Operating Temperature | -40 C to +125 C |
| Package | 20-pin SOIC (SO) - SOIC-20 |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC16F639-E/SO Pin Configuration
| Pin 1 | RA5/T1CKI/OSC1/CLKIN β I/O / Timer1 clock / oscillator input |
| Pin 2 | RA4/AN3/T1G/OSC2/CLKOUT β I/O / ADC input / Timer1 gate / oscillator output |
| Pin 3 | RA3/MCLR/VPP β I/O / Master Clear (reset) / programming voltage |
| Pin 4 | RA2/AN2/COUT/T0CKI/INT β I/O / ADC / comparator output / Timer0 clock / external interrupt |
| Pin 5 | RA1/AN1/C1-/C2-/VREF β I/O / ADC / comparator inverting inputs / voltage reference |
| Pin 6 | RA0/AN0/C1+/C2+/CVREF β I/O / ADC / comparator non-inverting inputs / CV reference |
| Pin 7 | VSS β Ground reference |
| Pin 8 | KIE / RB7 β KeeLoq indicator / I/O |
| Pin 9 | RB6 β I/O port B bit 6 |
| Pin 10 | RB5 β I/O port B bit 5 |
| Pin 11 | RB4 β I/O port B bit 4 |
| Pin 12 | RB3/CCP1 β I/O / Capture-Compare-PWM |
| Pin 13 | RB2/SDI/SDA β I/O / SPI data in / I2C data |
| Pin 14 | RB1/SDO/SCL β I/O / SPI data out / I2C clock |
| Pin 15 | RB0/SCK/SCL β I/O / SPI clock |
| Pin 16 | VDD β Positive supply voltage (2.0 V to 5.5 V) |
| Pin 17 | RC7/RX/DT β I/O / USART RX / data |
| Pin 18 | RC6/TX/CK β I/O / USART TX / clock |
| Pin 19 | RC5 β I/O port C bit 5 |
| Pin 20 | RC4 β I/O port C bit 4 |
Typical Applications
PIC16F639-E/SO is suitable for 6 applications: Automotive Remote Keyless Entry (RKE), Automotive Immobilizer / Passive Anti-Theft, Garage Door / Gate Opener Transmitter, Secure Industrial Access Token, Wireless Security Sensor / PIR Detector, Smart Meter Tamper-Detection Module.
Automotive Remote Keyless Entry (RKE)
The PIC16F639-E/SO's integrated KeeLoq hardware cipher makes it a natural fit for secure rolling-code RKE transmitters. The 3.5 KB Flash holds the KeeLoq encoder plus USART-driven RF transmit routines; the 256-byte EEPROM stores up to several transmission counters and encryption keys with 1M-cycle endurance. The 2.0-5.5 V supply allows direct connection to a single CR2032 coin cell while nanoWatt sleep modes extend battery life to multi-year lifetimes typical of automotive remotes. The 11 I/O pins easily accommodate 4-5 button inputs, an LED indicator, and a KeeLoq-coded RF data line to an external SAW-based or PLL transmitter such as the MICRF112 or MAX1472.
Recommended
Automotive Immobilizer / Passive Anti-Theft
In passive immobilizer systems the PIC16F639-E/SO acts as the LF base-station decoder that authenticates the transponder before allowing engine start. Its hardware KeeLoq block validates the rolling-code challenge-response in real time while the 10-bit ADC monitors the LF antenna tuning and the comparators detect presence of the key fob. The dual analog comparators also handle amplitude-shift keying demodulation from the LF receiver front-end. Operating temperature of -40 C to +125 C ensures reliable operation in automotive underhood and cabin environments across global climate zones.
Recommended
Garage Door / Gate Opener Transmitter
The PIC16F639-E/SO provides cost-effective encrypted transmission for residential and commercial garage-door or gate openers where KeeLoq security prevents code-grabbing replay attacks. Its 35-instruction PIC16 mid-range core is well within the budget of a small handheld 3-button transmitter; the 256-byte EEPROM stores 32-bit encrypted counters and the secret manufacturer key. The wide 2.0-5.5 V supply range supports a 3 V coin cell or a 3.6 V Li-SOCl2 primary battery for a 10-year shelf life.
Recommended
Secure Industrial Access Token
For industrial access tokens the PIC16F639-E/SO combines KeeLoq rolling-code encryption with the enhanced USART to communicate with an external secure RFID/NFC front end. The 10-bit ADC supports battery-voltage telemetry sent back over the secure channel, while nanoWatt sleep modes drop consumption below 100 nA between button presses to give years of life from a single coin cell. Programmable Low-Voltage Detect (PLVD) issues a graceful tamper flag when the supply falls below the secure-storage threshold.
Recommended
Wireless Security Sensor / PIR Detector
Wireless PIR or window/door sensors benefit from the PIC16F639-E/SO's low-power nanoWatt modes combined with secure KeeLoq-encoded transmissions to the alarm panel. The MCU spends >99% of its time in sleep consuming sub-microamp current and wakes on interrupt from the PIR or comparator threshold detection. The 2 comparators provide accurate window-comparator action on the PIR analog front-end; the 10-bit ADC reads battery and temperature for telemetry. Encryption prevents replay attacks that defeat simple fixed-code wireless sensors.
Recommended
Smart Meter Tamper-Detection Module
Smart electricity and water meters require tamper detection with cryptographic authentication - an ideal role for the PIC16F639-E/SO. The PLVD detects supply-side tamper attempts; the comparators monitor magnetic-field sensors; and the KeeLoq cipher securely transmits tamper events back to the utility's head-end system. The 256-byte EEPROM stores audit logs and key material with cryptographic write protection. The -40 C to +125 C rating handles outdoor meter enclosures and meter-base temperature extremes.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F639-E/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F639-I/SO | PIC16F639T-I/SO | PIC16F636-I/SO | PIC16F636-E/SO | PIC16F631-I/SO |
|---|---|---|---|---|---|---|
| Package | SOIC-20 (SO) | SOIC-20 (SO) - same | SOIC-20 (SO) - same | SOIC-20 (SO) - same | SOIC-20 (SO) - same | SOIC-20 (SO) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core Architecture | PIC16 mid-range 8-bit | PIC16 mid-range 8-bit | PIC16 mid-range 8-bit | PIC16 mid-range 8-bit | PIC16 mid-range 8-bit | PIC16 mid-range 8-bit |
| Program Memory (Flash) | 3.5 KB (2K x 14) | 3.5 KB (2K x 14) | 3.5 KB (2K x 14) | 3.5 KB (2K x 14) | 3.5 KB (2K x 14) | 1.75 KB (-50%) |
| RAM | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 128 bytes |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 128 bytes (-50%) | 128 bytes (-50%) | None (-100%) |
| KeeLoq Crypto Engine | Yes | Yes | Yes | No | No | No |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| 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 | 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 +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +125 C (extended) | -40 C to +85 C (industrial) |
Key Differentiators
- Integrated hardware KeeLoq cipher engine (vs PIC16F636-I/SO)
- 256-byte secure EEPROM for keys and counters (vs PIC16F631-I/SO)
- Mid-range PIC16 core with 5 MIPS throughput (vs PIC16F630-E/P)
- nanoWatt technology for sub-uA sleep (vs PIC16F636-E/SO)
Design Notes
Estimated: at 20 MHz / 5 V the PIC16F639-E/SO draws approximately 11 mA active, dropping to <1 uA in sleep. For a coin-cell RKE transmitter running mostly in sleep, average consumption of 1-2 uA is achievable, giving 5+ years of life from a 220 mAh CR2032. Always place a 100 nF decoupling capacitor within 5 mm of the VDD pin (pin 16) and a 10 uF bulk capacitor if a noisy regulator is upstream. Estimated battery-life figures are first-order only; always characterize your application.
MCLR (pin 3) must be pulled to VDD through a 10 kohm resistor; never leave it floating, or the device will intermittently reset. For ICSP programming, isolate MCLR from the rest of the circuit so the high-voltage VPP pulse does not back-drive external components. The KeeLoq module must be enabled in configuration bits (CWG bit) or the encryption routines will silently no-op, causing security failure in production.
For RF transmitters driven from PIC16F639-E/SO, keep the KeeLoq-coded data line short and away from the antenna trace. The PIC's enhanced USART provides clean 9-bit data framing needed for fixed-format transmitter modules such as MAX1472; use a hardware timer rather than software bit-banging to ensure jitter-free data edges. Place a series resistor (100-330 ohm) on the data line to dampen ringing into the SAW resonator.
At 20 MHz and 5 V the PIC16F639-E/SO dissipates roughly 50 mW internally. The SOIC-20 package thermal resistance is approximately 80 C/W (estimated), giving a junction rise of 4 C above ambient - well within the 125 C limit. No special thermal management is required even inside a sealed automotive keyfob enclosure.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified; for automotive AEC-Q100 requirements consult Microchip automotive-grade PIC portfolio.
