PIC16F84A-20I/P - 8-Bit 20MHz 1.75KB Flash MCU | Microchip
MPN: PIC16F84A-20I/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.85 | $3.85 |
| 10 | $3.47 | $34.70 |
| 100 | $3.08 | $308.00 |
| 500 | $2.74 | $1,370.00 |
| 1,000 | $2.43 | $2,430.00 |
PIC16F84A-20I/P Overview
A microcontroller (MCU) is a single-chip computer that contains a CPU, program memory, RAM, peripherals, and I/O. Microcontrollers belong to the broader integrated circuit family and are the foundation of embedded systems that automate industrial, consumer, and automotive products. The PIC16 mid-range family sits in Microchip's 8-bit portfolio between the baseline 12/14-bit cores and the 16-bit dsPIC/PIC24 lines, balancing code density, peripheral integration, and cost for entry-level to mid-tier designs.
Key features include 200 ns instruction execution, 8-bit timer/counter, 13 I/O pins with individual direction control, 4 MHz internal oscillator-free operation (relies on external crystal or RC), 256-byte EEPROM, in-circuit serial programming (ICSP) capability, watchdog timer with on-chip RC oscillator, and power-saving sleep mode. The device operates from 2.0 V to 5.5 V (industrial temp grade), draws less than 1 mA typical operating current at 5 V/4 MHz, and supports brown-out detection via the configuration bits. The 13 I/Os source/sink up to 25 mA, sufficient to drive small relays or LEDs directly.
The architecture is Harvard RISC with separate 14-bit program bus and 8-bit data bus, deep hardware stack of 8 levels, and configurable internal/external oscillator selection. Peripheral integration includes one 8-bit timer with prescaler and one 16-bit timer (Timer0/Timer1, depending on variant) and a synchronous serial port (SSP) for SPI/I2C master mode, supporting EEPROM and peripheral expansion. The Flash memory supports 1000 erase/write cycles typical and 40-year data retention, suitable for in-field firmware updates via ICSP.
Typical applications include hobbyist and educational platforms, consumer appliance controls, low-end automotive body electronics (non-AEC-Q100), sensor interfaces, lighting controllers, small motor drives via MOSFET gates, and serial-protocol bridges (SPI/UART). The 20 MHz speed with 5 V tolerance allows direct interfacing to legacy 5 V peripherals while the ICSP header keeps prototype iteration fast.
When designing with PIC16F84A-20I/P, remember it is NOT a drop-in replacement for PIC16F628A or PIC16F88 in all cases due to differing peripheral register layouts - verify register maps before migration. Always install a 100 nF decoupling capacitor on VDD close to the pin, a 10-100 ohm resistor on MCLR if not driven directly, and ensure the oscillator configuration bits match the chosen XT/HS/LP/RC mode to avoid start-up failures.
This page synthesizes distributor pricing, pin-compatible Microchip drop-in alternatives, and practical design notes not found in the manufacturer datasheet, delivering engineering context beyond raw specification tables.
Drop-in alternatives for PIC16F84A-20I/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-20I/P (same form factor and footprint) — differing in Package, Timers, Mounting Type, Core Architecture, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F84A-20/P
✅ Drop-In✓ In Stock
$1.72 / Unit
View Datasheet →PIC16F84A-04I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84A-04/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84A-20/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F84A-20I/SO
✅ Drop-In✓ In Stock
$2.2 / Unit
View Datasheet →PIC16F84A-04I/SO
✅ Drop-In✓ In Stock
$3.59 / Unit
View Datasheet →PIC16F84A-20I/P Maximum Ratings & Electrical Characteristics
| Product Family | PIC16 mid-range 8-bit MCU |
| Core Architecture | 8-bit RISC (Harvard) |
| Instruction Set | 35 single-word instructions |
| Clock Frequency (max) | 20 MHz |
| Instruction Cycle | 200 ns at 20 MHz |
| Program Memory (Flash) | 1.75 KB (1024 x 14 words) |
| Data RAM | 68 bytes |
| Data EEPROM | 64 bytes |
| I/O Pins | 13 |
| Supply Voltage | 2.0 V to 5.5 V |
| Operating Temperature | -40C to +85C (Industrial) |
| Timers | 1 x 8-bit Timer0 + Watchdog |
| Peripherals | SSP (SPI/I2C master), USART not present, ICSP |
| Package | PDIP-18 (P) |
| Mounting Type | Through-hole (THT) |
| MSL Level | 1 (unlimited) |
| RoHS Status | Compliant |
| Lead-Free / Halogen-Free | Lead-Free; Halogen-Free status unknown |
PIC16F84A-20I/P Pin Configuration
| Pin 1 | RA2 — PORTA bit 2 (digital I/O) |
| Pin 2 | RA3 — PORTA bit 3 (digital I/O) |
| Pin 3 | RA4 — PORTA bit 4 (digital I/O, also T0CKI timer0 clock input) |
| Pin 4 | MCLR/VPP — Master Clear (reset, active-low) / ICSP programming voltage |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — PORTB bit 0 (digital I/O, also external interrupt) |
| Pin 7 | RB1 — PORTB bit 1 (digital I/O) |
| Pin 8 | RB2 — PORTB bit 2 (digital I/O) |
| Pin 9 | RB3 — PORTB bit 3 (digital I/O) |
| Pin 10 | RB4 — PORTB bit 4 (digital I/O, interrupt-on-change) |
| Pin 11 | RB5 — PORTB bit 5 (digital I/O, interrupt-on-change) |
| Pin 12 | RB6 — PORTB bit 6 (digital I/O, ICSP clock) |
| Pin 13 | RB7 — PORTB bit 7 (digital I/O, ICSP data) |
| Pin 14 | VDD — Positive supply (+2.0 V to +5.5 V) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / clockout in RC mode |
| Pin 16 | OSC1/CLKIN — Oscillator input / external clock in |
| Pin 17 | RA0 — PORTA bit 0 (digital I/O) |
| Pin 18 | RA1 — PORTA bit 1 (digital I/O) |
Typical Applications
PIC16F84A-20I/P is suitable for 7 applications: Hobbyist and Educational Embedded Boards, Consumer Appliance Control, Sensor Interface and Signal Conditioning Hub, Lighting Controller and DMX Receiver, Serial Protocol Bridge and UART-to-SPI Converter, Industrial Control Panel MCU, Educational Trainer and PICkit Programmer Target Board.
Hobbyist and Educational Embedded Boards
The PIC16F84A-20I/P's 18-pin PDIP package, ICSP programming header pins, and well-documented 35-instruction RISC core make it ideal for breadboard-friendly educational designs and university microcontroller courses. The 20 MHz speed delivers 200 ns instruction cycle which is fast enough to demo UART bit-banging, simple control loops, and interrupt-driven GPIO. The 1.75 KB Flash accommodates student projects of meaningful size without external memory. Its industrial -40C to +85C range prevents classroom lab failures from heat issues.
Recommended
Consumer Appliance Control
The PIC16F84A-20I/P's low-cost 8-bit performance and 13 I/O pins drive LED indicators, relay coils, and user keypads in small kitchen and home appliances. The 25 mA I/O source/sink directly drives small signal relays or low-current LEDs without buffer transistors. The 64 bytes EEPROM stores user preferences (e.g., last-set timer) across power cycles. The 5 V tolerant I/O interfaces with legacy appliance button matrix and triac-driven AC loads. 20 MHz instruction throughput handles debounce, keypad scanning, and triac zero-cross timing in a single foreground loop.
Recommended
Sensor Interface and Signal Conditioning Hub
The PIC16F84A-20I/P can poll multiple analog sensors through an external ADC (no internal ADC) and format results over SPI to a host controller via the on-chip SSP peripheral. Its 68 RAM bytes hold several 10-bit ADC sample buckets and a small moving-average filter. The 1.75 KB Flash fits calibration routines and lookup tables. The 20 MHz cycle rate executes 8-channel polling in under 10 ms. Industrial temp grade suits outdoor sensor node enclosures.
Recommended
Lighting Controller and DMX Receiver
The PIC16F84A-20I/P's SSP peripheral implements SPI master to drive WS2812-style LED strips or DMX-512 dimmer outputs in compact lighting fixtures. The 13 I/O pins drive multi-channel MOSFET gate drivers controlling 12-24 V LED arrays. The 1.75 KB Flash stores chase patterns and color tables; 68 RAM holds per-channel PWM duty cycle values. At 20 MHz the bit-bang DMX break/Mark timing is achievable in software, eliminating the need for a dedicated DMX chip. Industrial temp rating suits commercial venue fixtures.
Recommended
Serial Protocol Bridge and UART-to-SPI Converter
The PIC16F84A-20I/P bridges legacy peripherals by bit-banging UART on PORTB while using the SSP peripheral for SPI master to a child sensor or EEPROM. The 35-instruction RISC set makes the bit-bang code compact; the 68 RAM provides buffering for short packets. The 20 MHz speed supports up to 115200 bps UART with a half-bit timer resolution for accurate sampling. The ICSP header allows in-field firmware upgrade via a 4-pin connector, convenient for installed bridges.
Recommended
Industrial Control Panel MCU
The PIC16F84A-20I/P's 18-pin PDIP form factor drops directly into legacy industrial control panel designs, providing a proven 8-bit core for HMI button matrix scanning, indicator LED multiplexing, and small relay sequencing. Its industrial -40C to +85C rating handles factory floor temperatures, and brown-out reset via configuration bits keeps the MCU in known state through supply glitches. The 64-byte EEPROM stores fault logs and runtime counters for maintenance access.
Recommended
Educational Trainer and PICkit Programmer Target Board
The PIC16F84A-20I/P remains a recommended target MCU on Microchip's PICkit 2/3 programmer training materials because of its documented instruction set, 1.75 KB Flash accommodating sample programs, and ICSP programming pins on RB6/RB7. Breadboard-friendly PDIP-18 lets students easily swap devices and observe register behavior. The 20 MHz clock is fast enough for interrupt demos and timer tutorials without overwhelming trace outputs on a logic analyzer.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F84A-20I/P — comparison, design guidance, and compliance information.
Selection Guide
Choose PIC16F84A-20/P instead when cost is paramount and your deployment is in a controlled 0C to +70C environment, accepting the commercial temperature limitation for lower unit cost. Choose PIC16F84A-04I/P for battery-powered or cost-sensitive applications where 4 MHz operation is sufficient (e.g., simple timing loops, slow polling). Switch to PIC16F628A or PIC16F88 only when you genuinely need USART, internal oscillator, or ADC and can rewrite the firmware. For automotive AEC-Q100 or USB connectivity, choose a newer PIC16 family member with explicit automotive grade and modern peripherals.
Comparison with Alternatives
| Parameter | This Product | PIC16F84A-20/P | PIC16F84A-04I/P | PIC16F84A-04/P | PIC16F84A-20/SO | PIC16F84A-20I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | PDIP-18 (P) | PDIP-18 | PDIP-18 | PDIP-18 | SOIC-18 (different PCB footprint) | SOIC-18 (different PCB footprint) |
| Max Clock Frequency | 20 MHz | 20 MHz | 4 MHz | 4 MHz | 20 MHz | 20 MHz |
| Operating Temperature | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) |
| Program Memory (Flash) | 1.75 KB | 1.75 KB | 1.75 KB | 1.75 KB | 1.75 KB | 1.75 KB |
| Data RAM | 68 bytes | 68 bytes | 68 bytes | 68 bytes | 68 bytes | 68 bytes |
| Data EEPROM | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes |
| 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 |
Key Differentiators
- Established PIC16 mid-range ecosystem with abundant documentation (vs PIC16F628A)
- 20 MHz speed grade delivers full 200 ns instruction cycle (vs PIC16F84A-04I/P)
- Industrial -40C to +85C rating vs commercial temp only (vs PIC16F84A-20/P)
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible (within 5 mm trace length) to the VDD pin (pin 14) with its ground return to the adjacent VSS pin (pin 5). Add a bulk 10 uF electrolytic or tantalum capacitor on the same supply rail feeding the MCU to handle transient loads from relays or LEDs. Estimated: peak transient current from 13 I/O switching simultaneously at 25 mA can approach 325 mA, requiring local bulk capacitance to prevent VDD droop.
Do not assume the PIC16F84A-20I/P is pin-compatible with PIC16F628A or PIC16F88 without firmware changes. PIC16F628A has 224 bytes RAM and a USART, and PIC16F88 has an internal oscillator and ADC - both move registers around in the SFR map. Existing PIC16F84A code targeting CONFIG word bits (especially oscillator selection and watchdog) may also need adjustment. Verify register names, banked RAM access, and configuration bit definitions against the target datasheet before committing to a migration.
Keep the MCLR/VPP pin (pin 4) trace short and route it away from high-frequency switching nodes - this pin carries the ICSP programming voltage and is sensitive to noise-induced resets. Place a 10 kohm-100 kohm pull-up resistor from MCLR to VDD unless the application requires manual reset. Estimated: stray capacitance above 50 pF on MCLR combined with slow rising edges can cause unintended resets during power-up, especially if watchdog is enabled.
The PIC16F84A-20I/P's 13 I/O pins have a maximum source/sink current of 25 mA per pin, but the total package dissipation limit is 800 mW across all I/O combined. Use series resistors (typically 330 ohm for 5 V LEDs) to limit current; do not exceed three pins simultaneously sourcing 25 mA each without thermal analysis. The 8-bit PORTB latch with weak internal pull-ups supports interrupt-on-change on RB4-RB7, useful for keypad matrix scanning at 20 MHz cycle.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - for automotive use select a PIC16 family member explicitly AEC-Q100 qualified. Halogen-free status not explicitly stated in verified web data.
