PIC16F84T-04I/SO - 4MHz 8-bit Flash MCU 1.75KB | Microchip
MPN: PIC16F84T-04I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.95 | $3.95 |
| 10 | $3.55 | $35.50 |
| 100 | $3.1 | $310.00 |
| 500 | $2.65 | $1,325.00 |
| 1,000 | $2.2 | $2,200.00 |
PIC16F84T-04I/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, data memory, peripherals, and I/O on one die. The PIC16F8X series is a classic 8-bit Harvard-RISC architecture belonging to the PIC16CXX mid-range family, characterized by 14-bit wide instruction words, an 8-level deep hardware stack, and only 35 single-word instructions. This legacy architecture sits within the broader taxonomy: PIC microcontroller -> 8-bit MCU -> microcontroller -> embedded processor -> semiconductor. The "T" suffix denotes tape-and-reel packaging and "I" denotes the industrial -40C to +85C operating temperature range; "04" specifies the 4 MHz oscillator grade.
Key differentiating features include the 1.75 KB self-programmable flash program memory that allows in-circuit serial programming (ICSP), 64 bytes of EEPROM for non-volatile data storage, and the nanoWatt technology power-managed sleep modes that drop quiescent current to microampere levels. The Harvard bus separates program and data paths to allow simultaneous fetch and execute, and 14-bit-wide instructions enable compact code density for embedded control tasks.
Typical applications are legacy industrial controllers, automotive body electronics, hobby robotics, sensor interface boards, and educational development platforms where a stable, well-documented 8-bit MCU with simple in-system programming is preferred over newer Cortex-M devices.
When designing with this part, confirm that the 4 MHz oscillator grade is adequate for instruction throughput (200 ns per instruction at 4 MHz clock, 10 MHz at 10 MHz grade). For new designs consider PIC16F84A-04I/SO which adds a revised silicon die with identical pinout.
This page synthesizes verified distributor pricing, drop-in same-package alternatives, and practical design notes not consolidated on any single distributor product page.
Drop-in alternatives for PIC16F84T-04I/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-04I/SO (same form factor and footprint) — differing in Package, Timers, Core Architecture, Operating Temperature, Instruction Cycle Time.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F84T-04/SO
✅ Drop-In✓ In Stock
$1.74 / Unit
View Datasheet →PIC16F84-04I/SO
✅ Drop-In✓ In Stock
$2.18 / Unit
View Datasheet →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-20I/SO
✅ Drop-In✓ In Stock
$2.2 / Unit
View Datasheet →PIC16F83T-10I/SO
✅ Drop-In✓ In Stock
$4.5 / Unit
View Datasheet →PIC16F84T-04I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Type | Flash |
| Program Memory Size | 1.75 KB (1K x 14) |
| RAM Size | 68 bytes |
| EEPROM Size | 64 bytes |
| Maximum Clock Speed | 4 MHz |
| Instruction Cycle | 200 ns (at 4 MHz) |
| Supply Voltage | 4.0 V to 5.5 V |
| Number of I/O Pins | 13 |
| Timers | 1 x 8-bit, 1 x 16-bit |
| Number of Instructions | 35 (single-word) |
| Hardware Stack | 8 levels |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 18-SOIC (0.295", 7.50 mm width) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel |
| Lifecycle Status | Active |
PIC16F84T-04I/SO Pin Configuration
| Pin 1 | RA2 — Digital I/O port A bit 2 |
| Pin 2 | RA3 — Digital I/O port A bit 3 |
| Pin 3 | RA4/T0CKI — Digital I/O port A bit 4 / Timer0 clock input (open-drain output) |
| Pin 4 | MCLR#/VPP — Master clear reset (active low) / programming voltage input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Digital I/O port B bit 0 / external interrupt input |
| Pin 7 | RB1 — Digital I/O port B bit 1 |
| Pin 8 | RB2 — Digital I/O port B bit 2 |
| Pin 9 | RB3 — Digital I/O port B bit 3 |
| Pin 10 | RB4 — Digital I/O port B bit 4 (interrupt-on-change) |
| Pin 11 | RB5 — Digital I/O port B bit 5 (interrupt-on-change) |
| Pin 12 | RB6/PGC — Digital I/O port B bit 6 / ICSP serial clock |
| Pin 13 | RB7/PGD — Digital I/O port B bit 7 / ICSP serial data |
| Pin 14 | VDD — Positive supply voltage (4.0 V to 5.5 V) |
| Pin 15 | OSC2/CLKOUT — Oscillator crystal output / clock output (FOSC/4) |
| Pin 16 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 17 | RA0 — Digital I/O port A bit 0 |
| Pin 18 | RA1 — Digital I/O port A bit 1 |
Typical Applications
PIC16F84T-04I/SO is suitable for 7 applications: Legacy Industrial Controller Board, Hobby Robotics and Education Platform, Automotive Body Electronics Retrofit, Sensor Interface and Signal Conditioning Board, Smart Home Sensor Node, Educational Development Board and Trainer, Small Appliance Control Board.
Legacy Industrial Controller Board
The PIC16F84T-04I/SO is a stable, long-lived 8-bit controller for legacy industrial PLC I/O boards and machine controllers where the installed base expects proven F84 firmware. Its 4 MHz clock grade yields a 200 ns instruction cycle sufficient for sequential logic scanning at typical 10-50 Hz loop rates, and 13 digital I/O pins directly drive 24 V opto-isolated inputs through resistor dividers while sinking relay coils via 25 mA sink capability. The industrial -40C to +85C temperature grade and 4.0 V to 5.5 V supply tolerate noisy factory power rails. Replacement is rarely needed - Microchip's PIC16F84 family has been in continuous production since the 1990s, ensuring spare-part availability for installed equipment. Flash in-circuit serial programming lets field updates be applied without desoldering.
Recommended
Hobby Robotics and Education Platform
The PIC16F84T-04I/SO remains a staple microcontroller in university embedded-systems courses and hobby robotics because of its 35-instruction RISC core, 8-level hardware stack, and abundant student-facing literature published since 1995. At 4 MHz the device reliably bit-bangs UART at 9600 baud and generates precise servo PWM pulses for RC servos on the 16-bit Timer1 peripheral, while the 13 digital I/O pins multiplex sensors (HC-SR04 ultrasonic, IR reflectance, bump switches) without external mux logic. The 1.75 KB flash stores modest control loops for line-following or sumobot behavior. Hobbyists value the ICSP header allowing rapid erase-and-reprogram cycles during development, and the SOIC-18 package is hand-solderable with basic tools. Cost is low enough to leave the controller on every robot in a classroom set.
Recommended
Automotive Body Electronics Retrofit
In automotive aftermarket body modules such as auxiliary light controllers, alarm-system brain boards, and seat-position memory controllers, the PIC16F84T-04I/SO handles logic sequencing for relays and indicators. Its 13 I/O pins operate as low-side drivers at 25 mA to switch 12 V automotive loads through external MOSFETs or bipolar transistors, while the 4 MHz instruction rate sequences alarm-arm delays and turn-signal flash patterns with negligible jitter. The industrial temperature grade survives under-dash thermal environments from -40C cold-start to +85C summer cabin soak. EEPROM stores user-configurable alarm sensitivity and seat memory without battery backup. Where higher immunity to load-dump transients is needed, an external TVS plus input filter is recommended; Microchip's AN205 supplement documents automotive EMC layout practices for this family.
Recommended
Sensor Interface and Signal Conditioning Board
The PIC16F84T-04I/SO is commonly deployed as a smart front-end for analog sensor arrays where local intelligence reduces data-bus traffic back to a host processor. Its 13 I/O pins read digital humidity, temperature, motion, and quadrature encoder sensors while software-implemented debouncing and linearization routines execute on the 4 MHz core. The 64-byte EEPROM stores calibration coefficients that compensate sensor-to-sensor variation across production batches. Watchdog timer and brown-out reset (BOR) protect unattended remote sensor nodes against firmware lockup and VDD brown-outs. When an integrated ADC is needed, the PIC16F818-I/SO upgrades to 5-channel 10-bit ADC in the same footprint - a useful migration path for sensor designs that later add analog channels without PCB rework.
Recommended
Smart Home Sensor Node
In wireless smart-home sensor nodes (window/door contacts, leak detectors, occupancy sensors), the PIC16F84T-04I/SO serves as a low-power supervisory controller that wakes on a digital interrupt, reads a sensor, and returns to sleep via the nanoWatt power-managed modes. The PORTB interrupt-on-change feature on RB4-RB7 wakes the core from sleep on a door-switch event without polling, keeping quiescent current in the microampere range when paired with an external ISM-band radio. The 64-byte EEPROM retains the device's network ID and last-known state across battery swaps. The 4 MHz clock grade is sufficient because most of the duty cycle is spent sleeping. Battery life is dominated by the radio, not the MCU; this part's modest sleep current makes it well-suited to coin-cell or 2xAA powered nodes.
Recommended
Educational Development Board and Trainer
Microcontroller trainers and university lab boards continue to specify the PIC16F84T-04I/SO because the F84 family is the most documented PIC architecture in textbooks, app notes, and instructor materials published over three decades. The 18-SOIC footprint leaves room for breadboard-friendly SOIC-to-DIP adapter boards, allowing students to swap controllers without soldering. Demonstration firmware - LED chasers, seven-segment multiplex, keypad scanning, and PWM motor drive - fits within the 1.75 KB flash with room for student exercises. The ICSP header accepts a PICkit programmer for in-circuit erase/write, and a 4 MHz resonator is the canonical clock source for classroom timing exercises. For instructors wanting more memory without redesign, the F84A and F819 drop into the same trainer PCB.
Recommended
Small Appliance Control Board
Small kitchen and household appliances - coffee makers, bread machines, humidifiers, and air purifiers - use the PIC16F84T-04I/SO as a low-cost user-interface brain. The 13 I/O pins drive multiplexed seven-segment displays through external transistors, scan 4x4 keypads for user input, and switch TRIAC drivers for heater or fan load control. EEPROM stores user presets (brew strength, timer settings) across power cycles. The 4 MHz clock executes brushed DC motor PWM at 1 kHz with comfortable timing margin. Industrial temperature rating tolerates toaster-oven and dishwasher-adjacent enclosures. Software-implemented zero-crossing detection on RB0/INT synchronizes TRIAC firing to the AC line for low-RFI heater control, a well-documented pattern in Microchip AN228 and AN242.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F84T-04I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F84T-04/SO | PIC16F84-04I/SO | PIC16F84A-04I/SO | PIC16F83T-10I/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC (0.295") | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Silicon Die | PIC16F84 (original) | PIC16F84 - same | PIC16F84 - same | PIC16F84A (revised) | PIC16F83 (predecessor) |
| Max Clock Speed | 4 MHz | 4 MHz - same | 4 MHz - same | 4 MHz - same | 10 MHz - higher |
| Flash Program Memory | 1.75 KB | 1.75 KB - same | 1.75 KB - same | 1.75 KB - same | 0.875 KB - 50% less |
| RAM | 68 bytes | 68 bytes - same | 68 bytes - same | 68 bytes - same | 36 bytes - 47% less |
| Operating Temp Range | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| Packaging | Tape & Reel | Tape & Reel - same | Tube | Tube | Tape & Reel - same |
| Supply Voltage Range | 4.0 V to 5.5 V | 4.0 V to 5.5 V - same | 4.0 V to 5.5 V - same | 2.0 V to 5.5 V - extended | 4.0 V to 5.5 V - same |
Key Differentiators
- Tape & Reel packaging for high-volume SMT assembly (vs PIC16F84-04I/SO (Tube))
- Industrial temperature grade -40C to +85C (vs PIC16F84T-04/SO (Commercial))
- Original F84 silicon die for legacy firmware binary compatibility (vs PIC16F84A-04I/SO (Revised silicon))
- Dual 8-bit + 16-bit timers with hardware interrupt (vs PIC16F83T-10I/SO (smaller flash))
Design Notes
The PIC16F84T-04I/SO VDD range is 4.0 V to 5.5 V for the 4 MHz clock grade. Place a 100 nF decoupling capacitor as close as possible (within 5 mm) to the VDD pin (14) with the ground return directly to VSS (pin 5) - do not share ground vias with high-current switching nodes. For battery-powered designs below 4 V use the PIC16LF84A-04I/SO variant which extends operation down to 2.0 V. The internal brown-out reset (BOR) is enabled by configuration bit and protects against VDD sags during motor inrush; configure BOR voltage to 4.0 V for the industrial-grade part to match the minimum operating voltage.
The 18-SOIC (7.50 mm wide body) footprint requires 0.050" (1.27 mm) pitch pads; keep power traces wide (>= 0.3 mm) on VDD and VSS to handle the 13 I/O pin sink surges simultaneously. Route the MCLR#/VPP line separately from noisy switching nodes - add a 10 kohm pull-up to VDD and a 100 nF cap to ground if the pin is also used as a digital input in production (to filter programming glitches). The ICSP pins RB6/PGC and RB7/PGD should have accessible test points or a 6-pin header for in-circuit programming without desoldering the part.
Do not exceed the 4 MHz clock specification - the 04 grade silicon will malfunction above this frequency even though the F84 family supports 10 and 20 MHz grades. The OSC1/OSC2 crystal mode requires a parallel-resonant crystal with 15-33 pF load capacitors; using a series-resonant crystal will fail to oscillate. The 64-byte EEPROM endurance is 1 million erase/write cycles minimum (F84A: 10 million) - implement wear-leveling for frequently-updated parameters. The RA4 pin is open-drain and requires an external pull-up resistor when used as an output.
Place the oscillator crystal or resonator within 5 mm of the OSC1/OSC2 pins and surround it with a ground pour to reduce EMI coupling into the clock traces. Keep digital I/O traces that switch high-current loads (>20 mA) at least 3 mm away from the oscillator network and the VDD decoupling capacitor. If using the ICSP RB6/RB7 pins as general I/O in the final application, add 4.7 kohm series resistors to the programming connector to limit current during in-circuit programming while still allowing the pins to function normally.
The PIC16F84T-04I/SO I/O pins have a transition time of approximately 10 ns; at this edge rate the part is unlikely to generate significant radiated EMI on its own, but the loads it switches can. For AC-line TRIAC control, place the zero-crossing detector on RB0/INT (which has hardware interrupt capability) and keep the high-voltage trace area minimal to reduce coupling into adjacent low-voltage signals. Use the internal weak pull-ups on PORTB (enabled via OPTION_REG) for keypad or switch matrices, eliminating external resistors and improving noise immunity through firmware debouncing in software.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified (industrial grade only, not automotive grade). Lead-free reflow compatible per JEDEC J-STD-020.