PIC16F84A-04E/P - 8-bit 4MHz Flash MCU, 1.75KB | Microchip
MPN: PIC16F84A-04E/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.1 | $31.00 |
| 100 | $2.78 | $278.00 |
| 500 | $2.45 | $1,225.00 |
| 1,000 | $2.2 | $2,200.00 |
PIC16F84A-04E/P Overview
A PIC16F-series 8-bit microcontroller is a RISC-based microcomputer built around the PIC Harvard architecture that separates program and data buses to allow simultaneous fetch and execute. PIC microcontrollers sit in the broader category hierarchy: 8-bit MCU -> microcontroller -> embedded controller -> semiconductor IC. They are widely used in cost-sensitive, low-power applications where deterministic timing and a small footprint matter more than raw compute performance.
Key features include 13 digital I/O pins across PORTA (5) and PORTB (8), individually selectable weak pull-ups on PORTB, interrupt-on-change on RB<7:4>, a 15-bit hardware timer (Timer0) with 8-bit prescaler, a 10-bit Timer0 prescaler, and an 8-bit Timer2 with PWM capability. The device also provides a Watchdog Timer with its own on-chip RC oscillator, in-circuit serial programming (ICSP), and low-power SLEEP mode for battery applications.
The architecture is based on a Harvard design with separate 14-bit program memory and 8-bit data memory buses, which lets the CPU fetch the next instruction while reading the current instruction's operand. This single-cycle fetch/execute yields 200 ns instruction time at 20 MHz (4 MHz for the -04 variant). The CMOS Flash process also enables in-system reprogramming without an external ROM eraser.
Typical applications include industrial control logic, hobbyist/educational embedded projects, simple sensor readouts, home automation nodes, and legacy product retrofits. The 18-pin PDIP package is breadboard-friendly and supports hand-soldering for development work.
A key design consideration is the operating voltage window: PIC16F84A devices are rated for 2.0V to 5.5V (5.5V maximum absolute), so 5V TTL logic systems are straightforward but a 3.3V rail may need level translation on digital I/O. Designers should also budget time to read the family datasheet - configuration word bits (WDTE, CP, etc.) control essential features.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC16F84A-04E/P — 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 PIC16F84A-04E/P (same form factor and footprint) — differing in Core Architecture, Package, Timers, Mounting Type, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F84A-04/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84A-04I/P
✅ Drop-In✓ In Stock
$1.65 / Unit
View Datasheet →PIC16F84-04I/P
✅ Drop-In✓ In Stock
$2.18 / Unit
View Datasheet →PIC16F84-04/SO
✅ Drop-In✓ In Stock
$3.19 / Unit
View Datasheet →PIC16F819-I/PTSL
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F818-I/P
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC16F628A-04/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84A-04E/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC Harvard 8-bit RISC |
| Maximum Clock Frequency | 4 MHz |
| Program Memory (Flash) | 1.75 KB (1K x 14) |
| Data RAM | 68 bytes |
| Data EEPROM | 64 bytes |
| Instruction Set | 35 single-word instructions |
| Instruction Execution Time | 200 ns at 4 MHz |
| Digital I/O Pins | 13 (PORTA 5 + PORTB 8) |
| Operating Voltage Range | 4.0 V to 5.5 V (extended temp) |
| Operating Temperature Range | -40 C to +125 C (extended, "E") |
| Package | 18-pin PDIP (P) |
| Timers | Timer0 (8-bit w/ 8-bit prescaler), Watchdog Timer with dedicated RC oscillator |
| Special Peripherals | PORTB weak pull-ups, RB<7:4> interrupt-on-change |
| Programming Interface | ICSP (In-Circuit Serial Programming) |
| RoHS Status | Compliant |
PIC16F84A-04E/P Pin Configuration
| Pin 1 | RA2 — Bidirectional digital I/O |
| Pin 2 | RA3 — Bidirectional digital I/O |
| Pin 3 | RA4/T0CKI — Digital I/O / Timer0 clock input (open-drain output) |
| Pin 4 | MCLR/VPP — Master Clear reset (active low) / programming voltage |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Digital I/O / external interrupt input |
| Pin 7 | RB1 — Digital I/O |
| Pin 8 | RB2 — Digital I/O |
| Pin 9 | RB3 — Digital I/O |
| Pin 10 | RB4 — Digital I/O / interrupt-on-change |
| Pin 11 | RB5 — Digital I/O / interrupt-on-change |
| Pin 12 | RB6/PGC — Digital I/O / ICSP clock |
| Pin 13 | RB7/PGD — Digital I/O / ICSP data |
| Pin 14 | VDD — Positive supply (2.0-5.5V) |
| Pin 15 | OSC2/CLKOUT — Crystal oscillator output / clock output |
| Pin 16 | OSC1/CLKIN — Crystal oscillator input / external clock |
| Pin 17 | RA0 — Bidirectional digital I/O |
| Pin 18 | RA1 — Bidirectional digital I/O |
Typical Applications
PIC16F84A-04E/P is suitable for 6 applications: Educational Embedded Projects, Industrial Control Logic Replacement, Hobbyist and DIY Electronics, Simple Sensor Readout Front-Ends, Legacy Product Retrofit and Repair, Appliance Control Modules.
Educational Embedded Projects
The PIC16F84A-04E/P has been a teaching staple for two decades because of its simple 35-instruction RISC core, 18-pin PDIP breadboard footprint, and forgiving 2.0V-5.5V supply range. The 4 MHz clock rate gives 1 MIPS performance - plenty for blinking LEDs, scanning keypads, and timing loops in university labs. The 1.75 KB Flash holds meaningful student projects while still forcing efficient code. The -40C to +125C extended temp suffix means the same part survives outdoor labs and lab-bench mishaps.
Recommended
Industrial Control Logic Replacement
Mature 24V industrial cabinets that use discrete 5V logic often retrofit the PIC16F84A-04E/P as a cost-effective glue-logic replacement for legacy 8051 or HC11 designs. The 13 GPIO pins handle sensor reads and relay drive, while the 200 ns instruction execution ensures deterministic loop timing for safety interlocks. The extended temperature range covers unheated enclosures, and ICSP allows in-system firmware updates via the RB6/RB7 pins without removing the chip. The 64-byte EEPROM gives non-volatile storage for calibration constants.
Recommended
Hobbyist and DIY Electronics
Hobbyists choose the PIC16F84A-04E/P for its through-hole 18-pin PDIP that drops into breadboards without soldering, plus its long history of free assembler tutorials. Projects from POV LED displays to model-railway controllers use the device's PORTB weak pull-ups for direct switch input. The 4 MHz speed is more than enough for slow human-interface tasks, and the ICSP header means firmware reflashes in seconds. With 1.75 KB Flash, builders can fit complete state machines for animation or sensor polling.
Recommended
Simple Sensor Readout Front-Ends
Battery-powered sensor transmitters use the PIC16F84A-04E/P as a low-power front-end that wakes periodically, takes a digital reading, and returns to sleep. The PIC16F84A's < 1 uA typical sleep current preserves coin-cell batteries across multi-year deployments. The 8-bit Timer0 serves as a wake-up interval counter when fed from an external 32.768 kHz crystal on T1OSC. GPIO pins read comparator or digital sensor outputs, and the 64-byte EEPROM stores calibration data across power cycles.
Recommended
Legacy Product Retrofit and Repair
Industrial equipment built in the late 1990s and early 2000s often shipped with PIC16F84A-04E/P controllers that are now failing from decade-old flash wearout. The same Microchip part number is still orderable, allowing direct swap-in repairs without PCB modification. The 18-pin PDIP is also socketed in many legacy designs, so replacement requires no desoldering. For new designs that need pin compatibility with legacy firmware, the PIC16F84A-04E/P remains the authentic match.
Recommended
Appliance Control Modules
White-goods appliances such as washing machines, dishwashers, and microwave ovens frequently use the PIC16F84A-04E/P as the user-interface controller because of its low cost, ample GPIO for button matrices and 7-segment digit drives, and reliable EEPROM storage for cycle settings. The extended -40 C to +125 C temperature rating covers motor-compartment heat, and the 5.5V absolute-max supply tolerates noisy rectified mains rails with proper decoupling. The 4 MHz speed keeps up with rotary-encoder scanning and buzzer tone generation.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F84A-04E/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F84A-04/P | PIC16F84A-04I/P | PIC16F84-04I/P | PIC16F819-I/P | PIC16F818-I/P | PIC16F628A-04/P |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | PDIP-18 | PDIP-18 - same | PDIP-18 - same | PDIP-18 - same | PDIP-18 - same | PDIP-18 - same | PDIP-18 - same |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 8 MHz (with internal 8 MHz) | 10 MHz (with internal) | 4 MHz |
| Program Memory (Flash) | 1.75 KB | 1.75 KB | 1.75 KB | 1.75 KB | 2.93 KB | 1.75 KB | 3.5 KB |
| Data RAM | 68 bytes | 68 bytes | 68 bytes | 68 bytes | 256 bytes | 128 bytes | 224 bytes |
| Data EEPROM | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 256 bytes | 64 bytes | 128 bytes |
| Operating Temperature | -40 C to +125 C (extended) | 0 C to +70 C (commercial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | 0 C to +70 C (commercial) |
| Internal Oscillator | No | No | No | No | Yes (8 MHz) | Yes (8 MHz) | Yes (4 MHz) |
| A/D Converter | No | No | No | No | Yes (10-bit) | Yes (10-bit) | No (comparators only) |
Key Differentiators
- Extended -40 C to +125 C temperature grade as standard part number (vs PIC16F84A-04/P)
- Through-hole PDIP-18 for breadboard-friendly prototyping (vs PIC16F84A-04/SS)
- Authentic original-spec part for legacy retrofits (vs PIC16F628A-04/P)
Design Notes
Decouple VDD (pin 14) with a 100 nF ceramic capacitor placed within 5 mm of the pin, plus a bulk 10 uF tantalum or aluminum electrolytic on the supply rail. PIC16F84A-04E/P supply range is 4.0V to 5.5V over the extended -40 C to +125 C grade; for 3.3V operation verify against the datasheet's parametric table or use a PIC16LF variant. Inductance from long VDD traces can cause reset glitches when the MCLR capacitor charges - keep the trace short.
Place the crystal or resonator within 5 mm of pins 15 (OSC2) and 16 (OSC1), with a ground guard ring to minimize coupling noise into the clock. For ICSP programming, keep RB6 (pin 12) and RB7 (pin 13) free of series resistors above 10 kOhm or capacitors above 10 pF, since these pins carry the programming clock and data during in-circuit serial programming. Adding a 4.7 kOhm pull-up on MCLR (pin 4) is standard practice.
Configuration word bits (WDTE, CP, PWRTE, FOSC) control essential functions and are often forgotten on first design. The default configuration has the Watchdog Timer enabled, which can cause confusing resets if the CLRWDT instruction is not serviced. Brown-out reset is not present on PIC16F84A - for supply droop protection, use an external voltage supervisor such as MCP100 on MCLR.
Compliance Information
RoHS and REACH compliance per Microchip product page. Not AEC-Q100 qualified (consumer/industrial grade only). For automotive applications requiring AEC-Q100, a PIC16F1x-series successor is recommended.
