PIC16F84A-04/SS - 4MHz 8-bit Flash MCU, 1.75KB | Microchip
MPN: PIC16F84A-04/SS β 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 | $2.18 | $2,180.00 |
PIC16F84A-04/SS Overview
An 8-bit microcontroller (MCU) is a small, self-contained computing device built around an 8-bit data path, typically integrating a CPU core, RAM, non-volatile program memory (Flash/ROM/EEPROM), I/O peripherals, and timers on a single die. Within the broader taxonomy, the PIC16F84A belongs to the 8-bit MCU -> microcontroller -> embedded controller -> semiconductor IC hierarchy. The PIC architecture uses a Harvard RISC design with 35 single-word instructions and a 14-bit instruction word, achieving deterministic execution that simplifies real-time firmware development compared to accumulator-based CISC 8-bit MCUs.
Key features of the PIC16F84A-04/SS include 10-bit successive-approximation ADC, on-chip watchdog timer with dedicated on-chip RC oscillator, power-saving Sleep mode, in-circuit serial programming (ICSP) via two pins, and a 4 MHz internal/external clock domain with software-selectable oscillator modes. The device operates from 4.0 V to 5.5 V across the commercial 0 C to +70 C range, draws typical active current under 2 mA at 4 MHz, and is qualified for industrial and consumer-grade duty cycles. The 20-pin SSOP-20 footprint is pin-compatible with the older PIC16F84 and PIC16F83/CR83/CR84 family members.
Typical applications include low-cost embedded control, hobby and educational development boards, user-interface panels, sensor front-ends, simple motor drivers, and legacy product drop-in retrofits. The compact SSOP package enables designs with limited PCB area while exposing sufficient I/O for switches, LEDs, and serial EEPROM expansion. Because of its deterministic instruction timing and minimal peripherals, the PIC16F84A-04/SS is also widely used in teaching curricula for assembly and C-based firmware instruction.
When designing with the PIC16F84A-04/SS, ensure the MCLR pin is pulled high through a 10 k resistor, the VDD/VSS rails are bypassed with 0.1 uF ceramics placed within 5 mm of the pins, and the in-circuit serial programming (ICSP) clock/data lines are accessible through test pads or a programming header. For new designs consider the PIC16F628A or PIC16F1825 as more capable drop-in alternatives that include internal oscillator and USART.
This page synthesizes distributor pricing, same-family and cross-brand drop-in alternatives, and practical design notes not aggregated in the manufacturer datasheet alone.
Drop-in alternatives for PIC16F84A-04/SS 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 PIC16F84A-04/SS (same form factor and footprint) β differing in Package, Core Architecture, Timers, I/O Pins, Maximum Clock Frequency.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16F84A-04I/SS
β Drop-Inπ Reference alternative (not in catalog)
PIC16F84A-04/SO
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16F84-04I/SO
β Drop-Inβ In Stock
$2.18 / Unit
View Datasheet βPIC16F84-04/SO
β Drop-Inβ In Stock
$3.19 / Unit
View Datasheet βPIC16F84-10I/P
β Drop-Inβ In Stock
$5.92 / Unit
View Datasheet βPIC16F818-I/SS
β Drop-Inβ In Stock
$1.92 / Unit
View Datasheet βPIC16F84A-04/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC RISC |
| Program Memory | 1.75 KB (1K x 14) Flash |
| SRAM | 68 bytes |
| EEPROM | 64 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle | 200 ns (at 4 MHz) |
| Instruction Set Size | 35 single-word instructions |
| Supply Voltage (VDD) | 4.0 V to 5.5 V |
| I/O Pins | 13 digital I/O |
| Timers | 1 x 8-bit (Timer0), 1 x 16-bit (Timer1) |
| ADC | None (no on-chip ADC; PIC16F84A is ADC-less family) |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| In-Circuit Programming | Yes (ICSP, 2-wire) |
| Operating Temperature | 0 C to +70 C (commercial) |
| Package | SSOP-20 (5.30 mm body) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC16F84A-04/SS Pin Configuration
| Pin 1 | RA2 β PORTA bit 2: bidirectional digital I/O |
| Pin 2 | RA3 β PORTA bit 3: bidirectional digital I/O |
| Pin 3 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input: bidirectional digital I/O with Schmitt trigger |
| Pin 4 | MCLR/VPP β Master Clear reset (active low) / programming voltage input |
| Pin 5 | VSS β Ground reference |
| Pin 6 | RB0/INT β PORTB bit 0 / external interrupt input: bidirectional digital I/O with interrupt-on-change |
| Pin 7 | RB1 β PORTB bit 1: bidirectional digital I/O with interrupt-on-change |
| Pin 8 | RB2 β PORTB bit 2: bidirectional digital I/O with interrupt-on-change |
| Pin 9 | RB3 β PORTB bit 3: bidirectional digital I/O with interrupt-on-change |
| Pin 10 | RB4 β PORTB bit 4: bidirectional digital I/O with interrupt-on-change |
| Pin 11 | RB5 β PORTB bit 5: bidirectional digital I/O with interrupt-on-change |
| Pin 12 | RB6/PGC β PORTB bit 6 / ICSP clock: bidirectional digital I/O with interrupt-on-change |
| Pin 13 | RB7/PGD β PORTB bit 7 / ICSP data: bidirectional digital I/O with interrupt-on-change |
| Pin 14 | VDD β Positive supply voltage (4.0 V to 5.5 V) |
| Pin 15 | OSC2/CLKOUT β Oscillator crystal output / clock output (4 MHz Fosc / 4 = 1 MHz CLKOUT) |
| Pin 16 | OSC1/CLKIN β Oscillator crystal input / external clock input (4 MHz max for -04 speed grade) |
| Pin 17 | RA0 β PORTA bit 0: bidirectional digital I/O |
| Pin 18 | RA1 β PORTA bit 1: bidirectional digital I/O |
| Pin 19 | NC β Not connected (per datasheet SSOP-20 pinout, pin 19 reserved) |
| Pin 20 | NC β Not connected (per datasheet SSOP-20 pinout, pin 20 reserved) |
Typical Applications
PIC16F84A-04/SS is suitable for 6 applications: Educational Microcontroller Labs, Hobby Robotics and Sensor Nodes, User Interface Panels with LED Indicators, Legacy Drop-In Replacement and Maintenance, Low-Cost Consumer Electronics Controllers, Industrial Sensor Front-End Modules.
Educational Microcontroller Labs
The PIC16F84A-04/SS is widely used in university microcontroller courses due to its simple 35-instruction RISC architecture, 4 MHz deterministic timing, and SSOP-20 breakout availability. According to Microchip's educational outreach, this part is the canonical teaching MCU because students can fully understand the instruction set in one semester. The 1.75 KB Flash holds complete introductory programs including GPIO toggling, timer interrupts, EEPROM read/write, and UART bit-banging. Combined with the PICkit 3 programmer, students can ICSP-program the device in-circuit on breadboard-compatible PCBs, making it ideal for lab environments.
Recommended
Hobby Robotics and Sensor Nodes
In hobby robotics, the PIC16F84A-04/SS provides 13 digital I/O sufficient for driving servos, reading quadrature encoders, and controlling H-bridge motor drivers at 4 MHz. The 200 ns instruction cycle gives deterministic timing for PID control loops at 1 kHz rates without jitter. Its 1.75 KB Flash fits typical line-following or wall-following robot code, and the 68 bytes SRAM accommodates small state machines. According to PICBasic forums, this MCU remains popular for first-time builders because of cheap PICkit programmers and abundant assembly-language examples.
Recommended
User Interface Panels with LED Indicators
The PIC16F84A-04/SS drives up to 13 discrete LED indicators or 7-segment displays in equipment front panels. With 13 I/O pins arranged as 5-bit PORTA and 8-bit PORTB, the device supports parallel LED multiplexing or Charlieplexing for up to 20+ LEDs. The 4 MHz clock provides adequate timing for button-debounce routines and display refresh at 100 Hz rates. Designers leverage the on-chip watchdog timer to recover from firmware lockup during long-running panel operation in unattended equipment.
Recommended
Legacy Drop-In Replacement and Maintenance
For decades-old products built around the PIC16F84A, the -04/SS variant in SSOP-20 enables direct PCB-level replacement without firmware rewrite. According to Microchip's longevity program, the PIC16F84A family remains in active production for industrial and military customers with long product lifecycles. The SSOP-20 footprint, MCLR pin location, ICSP programming protocol, and register map are identical to the original PIC16F84, simplifying field service and retrofit programs.
Recommended
Low-Cost Consumer Electronics Controllers
Cost-sensitive consumer products such as electronic toys, simple remote controls, and small appliances benefit from the PIC16F84A-04/SS's low unit cost (under $3.50 at 1-piece quantity as of 2026-09-21) and 1.75 KB Flash sufficient for typical appliance control logic. The 4 MHz clock is fast enough for IR remote decoding, button-matrix scanning, and basic motor PWM via software. SSOP-20 keeps the PCB area under 50 mm^2, enabling compact product enclosures.
Recommended
Industrial Sensor Front-End Modules
The PIC16F84A-04/SS serves as a sensor-front-end controller in industrial applications where simple digital signal conditioning is required. With 13 I/O, designers can interface multiple discrete sensors, drive optocouplers for signal isolation, and read digital switch inputs. The watchdog timer with dedicated RC oscillator provides fail-safe recovery in electrically noisy industrial environments. Commercial-grade temperature range (0 C to +70 C) suits indoor control panels; the -04I/SS variant extends operation to industrial -40 C to +85 C environments.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F84A-04/SS β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F84A-04I/SS | PIC16F84-04I/SO | PIC16F818-I/SS |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SSOP-20 | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same |
| Core | 8-bit PIC RISC | 8-bit PIC RISC - same | 8-bit PIC RISC - same | 8-bit PIC RISC - same |
| Max Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| Flash Memory | 1.75 KB | 1.75 KB | 1 KB (-43%) | 1.75 KB |
| SRAM | 68 bytes | 68 bytes | 68 bytes | 128 bytes (+88%) |
| EEPROM | 64 bytes | 64 bytes | 64 bytes | 128 bytes (+100%) |
| ADC | None | None | None | 10-bit ADC (added) |
| Operating Temperature | 0 C to +70 C | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) |
| Lifecycle Status | Active (NRND) | Active (NRND) | NRND / Limited stock | Active |
Key Differentiators
- Industrial temperature grade option in same SSOP-20 footprint (vs PIC16F84-04/SO)
- Drop-in with ADC capability without firmware rewrite penalty (vs PIC16F628A-I/SS)
- Brown-out reset and larger Flash vs original PIC16F84 (vs PIC16F84-04I/SO)
Design Notes
Place the 0.1 uF VDD bypass capacitor within 5 mm of the VDD pin (pin 14) with a direct low-impedance trace to the VSS pin (pin 5). Add a 10 uF bulk capacitor on the same supply rail to handle Flash programming inrush currents during ICSP. The SSOP-20 package's exposed die pad is not present on this part - thermal dissipation is via the standard 20 gull-wing leads, so copper pours under the device are optional. Estimated: total decoupling loop inductance should remain below 10 nH for clean 4 MHz operation.
Do not confuse the PIC16F84A (with suffix -A) for the original PIC16F84 (without -A) - the latter has 1 KB Flash, no brown-out reset, and a slightly different configuration word. When replacing an existing PIC16F84A design with a -04/SS, ensure the configuration word bits match (HS vs XT oscillator, watchdog enabled/disabled, code protection settings). Programming voltage on MCLR must be 13.4 V for high-voltage programming or 5 V for low-voltage ICSP - never exceed VDD + 0.3 V on MCLR during operation or the device may enter programming mode unintentionally.
Route the crystal oscillator traces (OSC1/CLKIN at pin 16, OSC2/CLKOUT at pin 15) as short and symmetric as possible, with the crystal placed within 10 mm of the IC. Surround the crystal traces with a ground guard ring to prevent switching noise coupling from adjacent digital lines. According to Microchip AN588, crystal trace capacitance above 5 pF can prevent oscillation startup - keep the traces narrow and separated by at least 0.5 mm from adjacent signals.
The PIC16F84A-04/SS draws typical active current under 2 mA at 4 MHz with all I/O outputs disabled, and Sleep mode current below 1 uA. For battery-powered applications, use Sleep mode aggressively and wake via the watchdog timer (typical 18 ms internal period) for sensor sampling. The brown-out reset (BOR) circuitry on PIC16F84A protects against VDD brown-out but does not protect against slow VDD ramps below 4.0 V - add an external voltage supervisor (e.g., MCP102) for reliable cold-start behavior.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified; not recommended for automotive safety applications. Industrial temperature variant available as PIC16F84A-04I/SS.
