PIC16F84T-04/SO - 4MHz 1.75KB Flash 8-bit MCU | Microchip
MPN: PIC16F84T-04/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.71 | $2.71 |
| 10 | $2.44 | $24.40 |
| 100 | $2.17 | $217.00 |
| 500 | $1.95 | $975.00 |
| 1,000 | $1.74 | $1,740.00 |
PIC16F84T-04/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, digital peripherals, and I/O onto one semiconductor die. The PIC16F8X belongs to the broader PIC16CXX family of low-cost, high-performance, fully-static CMOS 8-bit microcontrollers, which sit within the wider taxonomy of microcontrollers -> embedded microcontrollers -> microprocessors -> semiconductors. The PIC16F84T-04/SO specifically uses Microchip's enhanced Harvard RISC architecture with only 35 single-word instructions, making it approachable for both educational and production designs.
Key features include 4 MHz maximum operating frequency (200 ns instruction cycle for the -04 variant), 68 bytes of RAM, 64 bytes of EEPROM data memory, 13 digital I/O pins, and a 10-bit timer/counter. The device supports in-circuit serial programming (ICSP), code protection, and operates from 2.0 V to 5.5 V (industrial) or 4.0 V to 5.5 V (extended), enabling battery and 5 V bus designs. The CMOS process delivers low power consumption suitable for nanoWatt applications.
The PIC16F84T-04/SO employs a RISC Harvard architecture, separating program and data buses to fetch instruction and operand simultaneously. With only 35 instructions and single-cycle execution for most opcodes, deterministic interrupt response is achievable. Internal features such as power-on reset, brown-out detect, watchdog timer, and code protection simplify firmware development and improve field reliability.
Typical applications include hobbyist projects, low-end industrial controllers, automotive aftermarket devices, simple sensor interfaces, and legacy embedded designs where pin compatibility with the PIC16F84 is required. The wide operating voltage and CMOS power economy also suit battery-powered devices.
When designing with this MCU, pay attention to the ICSP pinout (RB6/RB7) to reserve programming access and add decoupling per Microchip's guidelines. Use the -04 suffix as the indicator of the 4 MHz part; faster 10 MHz (-10) and 20 MHz (-20) parts exist in the same package for speed upgrades.
Drop-in alternatives for PIC16F84T-04/SO — 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 PIC16F84T-04/SO (same form factor and footprint) — differing in Package, Core Architecture, Timers, I/O Pins, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F84-04/SO
✅ Drop-In✓ In Stock
$3.19 / Unit
View Datasheet →PIC16F84A-04I/SO
✅ Drop-In✓ In Stock
$3.59 / Unit
View Datasheet →PIC16F84A-04E/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84A-20/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F84A-04I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84T-04/SO Maximum Ratings & Electrical Characteristics
| Core | PIC16 |
| Architecture | 8-bit RISC Harvard |
| Maximum Clock Speed | 4 MHz (-04 suffix) |
| Instruction Cycle | 200 ns (at 20 MHz input, 4 MHz oscillator) |
| Program Memory (Flash) | 1.75 KB (1K x 14 words) |
| RAM | 68 bytes |
| EEPROM Data Memory | 64 bytes |
| I/O Pins | 13 |
| Timers | 1 x 8-bit Timer0 |
| Instruction Set Size | 35 instructions |
| Supply Voltage (VDD) | 4.0 V to 5.5 V |
| Operating Temperature | 0C to +70C (commercial) |
| Package | 18-pin SOIC (SO), 300 mil |
| Packaging | Tape and Reel (T suffix) |
| Mounting Type | Surface Mount |
| Program Memory Type | Flash |
| Programming Method | ICSP (In-Circuit Serial Programming) |
| Watchdog Timer | Yes |
| Brown-out Detect | Yes |
| RoHS Status | Compliant |
PIC16F84T-04/SO Pin Configuration
| Pin 1 | RA2 — Digital I/O pin (PORTA bit 2) |
| Pin 2 | RA3 — Digital I/O pin (PORTA bit 3) |
| Pin 3 | RA4/T0CKI — Digital I/O pin with Timer0 external clock input (open-drain) |
| Pin 4 | MCLR/VPP — Master Clear reset input / programming voltage |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Digital I/O with external interrupt (PORTB bit 0) |
| Pin 7 | RB1 — Digital I/O pin (PORTB bit 1) |
| Pin 8 | RB2 — Digital I/O pin (PORTB bit 2) |
| Pin 9 | RB3 — Digital I/O pin (PORTB bit 3) |
| Pin 10 | RB4 — Digital I/O with interrupt-on-change (PORTB bit 4) |
| Pin 11 | RB5 — Digital I/O with interrupt-on-change (PORTB bit 5) |
| Pin 12 | RB6/PGC — Digital I/O with interrupt-on-change / ICSP clock (PORTB bit 6) |
| Pin 13 | RB7/PGD — Digital I/O with interrupt-on-change / ICSP data (PORTB bit 7) |
| Pin 14 | VDD — Positive supply voltage (4.0 V to 5.5 V) |
| Pin 15 | OSC2/CLKOUT — Crystal oscillator output / clock output |
| Pin 16 | OSC1/CLKIN — Crystal oscillator input / external clock input |
| Pin 17 | RA0 — Digital I/O pin (PORTA bit 0) |
| Pin 18 | RA1 — Digital I/O pin (PORTA bit 1) |
Typical Applications
PIC16F84T-04/SO is suitable for 6 applications: Educational and Hobbyist Embedded Projects, Low-End Industrial Control and Sensor Interfaces, Automotive Aftermarket and Accessory Controllers, Legacy Replacement and Through-Hole PCB Repair, Battery-Powered Wireless Sensor Nodes, Smart Home and IoT Edge Devices.
Educational and Hobbyist Embedded Projects
The PIC16F84T-04/SO is a canonical teaching MCU for introductory embedded systems courses and DIY hobbyist projects. Its 35-instruction RISC architecture is simple enough to learn in a semester yet powerful enough for genuine standalone products. The 4 MHz clock with 200 ns instruction cycle provides deterministic real-time response for sensor reading and actuator control, while 1.75 KB Flash fits typical classroom projects such as digital thermometers, reaction-time games, and LED pattern controllers. PIC microcontroller tutorials and textbooks use this part as the reference design, so students find abundant example code. The ICSP interface on RB6/RB7 lets instructors program the part repeatedly without removing it from a development board.
Recommended
Low-End Industrial Control and Sensor Interfaces
The PIC16F84T-04/SO suits low-end industrial sensor interfacing and simple relay-driver applications. Its 13 digital I/O pins can directly drive 25 mA loads at each pin, sufficient for optocouplers, LEDs, small relays, and logic-level translation to higher-power peripherals. Brown-out detection and watchdog timer features add field reliability, while the 64-byte EEPROM stores calibration constants and configuration data across power cycles. The 4 MHz clock provides adequate throughput for polling sensors at 100 Hz rates and toggling outputs in response. Applications include HVAC damper controllers, vending machine coin detectors, simple PLC replacements, and instrumentation front-ends where cost dominates over computational demands.
Recommended
Automotive Aftermarket and Accessory Controllers
The PIC16F84T-04/SO serves in 12 V automotive aftermarket accessory controllers such as alarm systems, remote keyless entry receivers, and lighting controllers. Its 4.0-5.5 V VDD range aligns with 5 V regulated rails derived from the vehicle's 12 V bus via simple linear regulators. The 13 I/O pins support switch inputs, relay outputs, and serial communication with companion RF or infrared receivers. EEPROM retains user settings (alarm codes, lighting preferences) through battery disconnects. The PIC16F84A variant with -E (extended) temperature grade is preferred for under-hood applications, but the standard commercial-temperature PIC16F84 suffices for cabin-mounted accessories.
Recommended
Legacy Replacement and Through-Hole PCB Repair
The PIC16F84T-04/SO is widely specified in legacy through-hole PCB designs and serves as a modern surface-mount replacement when repairing older equipment. Designs from the late 1990s and early 2000s often use the original PIC16F84 in PDIP-18; the SOIC version provides the same silicon in a smaller package for board-modernization projects. Hobbyists restoring vintage equipment, museums preserving interactive exhibits, and industrial maintenance teams keeping legacy machinery running benefit from Microchip's continued production of this mature part. The -04 speed grade matches original 4 MHz designs without firmware modification.
Recommended
Battery-Powered Wireless Sensor Nodes
The PIC16F84T-04/SO functions as a low-power supervisory controller in battery-powered wireless sensor nodes where its CMOS implementation and 4 MHz clock enable microamp-range sleep currents. The device handles housekeeping tasks such as timing sensor wake cycles, assembling transmit packets, and managing a companion RF transceiver via GPIO bit-banging. With brown-out detect guarding against low-battery lockups and watchdog timer recovering from RF-induced software faults, the part is well-suited to remote environmental monitors, weather stations, and agricultural sensor pods. The 64-byte EEPROM retains calibration data and node IDs across battery replacements.
Recommended
Smart Home and IoT Edge Devices
The PIC16F84T-04/SO is suitable for entry-level smart home controllers such as simple occupancy sensors, manual override switches, and basic edge devices. Its deterministic 4 MHz execution and 35-instruction simplicity allow quick response to user inputs (button presses, motion sensor triggers) and simple protocol translation to a host microcontroller over UART-style bit-banging. The ICSP interface lets installers reprogram devices in the field without disassembly. For more demanding IoT nodes requiring ADC for analog sensor integration, the PIC16F84A variant is preferred, but the original PIC16F84 suffices for purely digital control points such as relay drivers and switch panels.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F84T-04/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F84-04/SO | PIC16F84A-04I/SO | PIC16F84A-04E/SO | PIC16F84A-20/SO | PIC16F84A-04I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-pin SOIC (300 mil) | 18-pin SOIC (300 mil) - same | 18-pin SOIC (300 mil) - same | 18-pin SOIC (300 mil) - same | 18-pin SOIC (300 mil) - same | 18-pin PDIP - through-hole variant |
| Maximum Clock Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 4 MHz |
| Supply Voltage (VDD) | 4.0 V to 5.5 V | 4.0 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 |
| Program Memory | 1.75 KB Flash | 1.75 KB Flash | 1.75 KB Flash | 1.75 KB Flash | 1.75 KB Flash | 1.75 KB Flash |
| Operating Temperature | 0C to +70C (commercial) | 0C to +70C | -40C to +85C (industrial) | -40C to +125C (extended) | 0C to +70C | -40C to +85C (industrial) |
| Instruction Set | 35 instructions (14-bit) | 35 instructions | 35 instructions (enhanced) | 35 instructions (enhanced) | 35 instructions (enhanced) | 35 instructions (enhanced) |
| Packaging Format | Tape and Reel | Tube | Tube | Tube | Tube | Tube (PDIP) |
Key Differentiators
- Wider supply voltage range on the PIC16F84A family (vs PIC16F84-04/SO)
- Higher speed upgrade path in same SOIC package (vs PIC16F84A-04I/SO)
- Extended temperature grade option for industrial/automotive (vs PIC16F84A-04I/SO)
Design Notes
The PIC16F84T-04/SO requires a stable 4.0 V to 5.5 V supply; place a 100 nF decoupling capacitor as close as possible to the VDD pin (14), with a bulk 10 uF tantalum or ceramic capacitor on the supply rail. For battery-powered designs, the PIC16F84A variant (2.0-5.5 V) is preferred to support lower battery voltages. Brown-out detection should be enabled in the configuration word to reset the MCU when VDD drops below threshold, preventing EEPROM corruption.
Reserve access to the RB6/PGC (pin 12) and RB7/PGD (pin 13) signals plus MCLR/VPP (pin 4) for ICSP programming. A 5-pin header (or Tag-Connect footprint) should be exposed on the PCB to allow field programming. Place the crystal or resonator (pins 15/16) within 5 mm of the MCU with short traces, and keep clock traces away from high-current switching signals to avoid injection of noise into the oscillator circuit.
Do not exceed the 25 mA per-pin I/O source/sink limit, or the 100 mA per-port limit, or the 200 mA total VDD/GND current limit specified in the Microchip datasheet. Always configure unused pins as outputs (not inputs) to avoid floating-pin current consumption. The MCLR pin must be pulled high through a 10 kohm resistor unless external reset control is desired; do not leave MCLR floating.
Compliance Information
RoHS and REACH compliant per Microchip product page. Lead-free matte-tin finish. Not AEC-Q100 qualified - select PIC16F84A -E extended temp variants for harsh environments. Halogen-free per Microchip environmental compliance data.
