PIC16F84A-04E/SO - 4MHz 8-Bit Flash MCU, 1.75KB | Microchip
MPN: PIC16F84A-04E/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.78 | $37.80 |
| 100 | $3.25 | $325.00 |
| 500 | $2.84 | $1,420.00 |
| 1,000 | $2.45 | $2,450.00 |
PIC16F84A-04E/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (Flash/ROM), data memory (RAM), non-volatile storage (EEPROM), and peripheral I/O onto one silicon die. The PIC16F family sits in Microchip's mid-range architecture taxonomy: 8-bit MCU -> PIC mid-range -> PIC16F -> PIC16F84A. This category hierarchy explains why the PIC16F84A-04E/SO is widely used as an introductory and hobbyist platform - the 35-instruction RISC instruction set is small enough to learn quickly, yet powerful enough to drive real industrial and embedded designs.
Key features include the Harvard bus architecture that lets the CPU fetch instructions and data simultaneously, an instruction pipelining scheme that overlaps fetch and execute cycles, and the in-circuit serial programming (ICSP) interface that allows Flash reprogramming without removing the part from the board. The 64-byte on-chip EEPROM supports 1M erase/write cycles typical, enabling non-volatile parameter storage without an external serial EEPROM. The 13 I/O pins can source or sink up to 25mA each, making them capable of directly driving small relays or LED arrays without buffer transistors.
Typical applications include legacy industrial controllers, low-cost consumer appliances, hobbyist and educational development boards, automotive interior accessory modules, and remote sensor nodes where the 4MHz clock and 1.75KB Flash are sufficient for periodic polling and interrupt-driven control. Designers migrating from the older PIC16F84 should reference Microchip's migration document, since the PIC16F84A adds hardware improvements such as a 4x PLL option, extended interrupt capability, and lower power consumption.
A practical design consideration when using this MCU is its 4MHz maximum oscillator frequency - at higher speeds the designer must move to the PIC16F84A-20 variant. Always place a 0.1uF decoupling capacitor directly across VDD/VSS within 5mm of the pins, and reserve the MCLR pin for a proper reset network (10k pull-up to VDD with a 100nF cap to ground) unless the internal reset is being explicitly relied upon.
This page synthesizes real-time distributor pricing, verified drop-in alternative MPNs, and practical engineering design notes drawn from Microchip's datasheet and reference documentation - information not consolidated on a single DigiKey or Mouser product listing.
Drop-in alternatives for PIC16F84A-04E/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 PIC16F84A-04E/SO (same form factor and footprint) — differing in Core Architecture, Package, I/O Pins, Instruction Set, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F84A-04I/SO
✅ Drop-In✓ In Stock
$3.59 / Unit
View Datasheet →PIC16F84A-04/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84A-20/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F84A-10/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F84A-04E/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 (8-bit RISC, Harvard) |
| Core Speed (Max) | 4 MHz |
| Instruction Execution Time | 200 ns (one instruction per cycle at 4 MHz) |
| Program Memory (Flash) | 1.75 KB (1K x 14 words) |
| Data Memory (SRAM) | 68 bytes |
| Data EEPROM | 64 bytes |
| Number of I/O Pins | 13 |
| Package | 18-SOIC (0.295 in / 7.50 mm width) |
| Mounting Type | Surface Mount |
| Operating Temperature Range (E suffix) | -40 C to +125 C (Extended) |
| Peripherals | POR (Power-On Reset), WDT (Watchdog Timer), 10-bit prescaler, ICSP |
| Timer Modules | 1 x 8-bit Timer0 with programmable prescaler |
| I/O Pin Drive Strength | 25 mA source/sink per pin |
| Instruction Set Size | 35 single-word instructions |
| Programming Interface | ICSP (In-Circuit Serial Programming) via RB6/RB7 |
| Supply Voltage (VDD) | 2.0 V to 5.5 V (Extended temp, RC/HS/XT modes) |
| RoHS Status | Compliant |
PIC16F84A-04E/SO Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O pin, Port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O pin, Port A bit 3 |
| Pin 3 | RA4/T0CKI — Bidirectional I/O pin / Timer0 clock input, open-drain |
| Pin 4 | MCLR — Master Clear (reset) input, active low; tie to VDD via 10k pull-up |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Bidirectional I/O pin, Port B bit 0 / external interrupt input |
| Pin 7 | RB1 — Bidirectional I/O pin, Port B bit 1 |
| Pin 8 | RB2 — Bidirectional I/O pin, Port B bit 2 |
| Pin 9 | RB3 — Bidirectional I/O pin, Port B bit 3 |
| Pin 10 | RB4 — Bidirectional I/O pin, Port B bit 4 / interrupt-on-change |
| Pin 11 | RB5 — Bidirectional I/O pin, Port B bit 5 / interrupt-on-change |
| Pin 12 | RB6/PGC — Bidirectional I/O pin, Port B bit 6 / ICSP clock (PGC) |
| Pin 13 | RB7/PGD — Bidirectional I/O pin, Port B bit 7 / ICSP data (PGD) |
| Pin 14 | VDD — Positive supply voltage (+2.0 V to +5.5 V) |
| Pin 15 | OSC2/CLKOUT — Oscillator crystal output / CLKOUT for RC mode |
| Pin 16 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 17 | RA0 — Bidirectional I/O pin, Port A bit 0 |
| Pin 18 | RA1 — Bidirectional I/O pin, Port A bit 1 |
Typical Applications
PIC16F84A-04E/SO is suitable for 6 applications: Hobbyist and Educational Development Boards, Legacy Industrial Controller Retrofit, Automotive Interior Accessory Module, Low-Cost Consumer Appliance Control, Remote Sensor Node with Polled Sampling, In-Circuit Serial Programming (ICSP) Development Target.
Hobbyist and Educational Development Boards
The PIC16F84A-04E/SO is the canonical MCU for introductory embedded systems courses and hobbyist projects because of its 35-instruction RISC architecture. A beginner can master the entire instruction set in a weekend, yet the device delivers 4 MHz / 5 MIPS peak performance, 1.75 KB Flash for code, and 13 I/O pins capable of 25 mA source/sink per pin - enough to drive LEDs, buzzers, and small DC motors directly without buffer transistors. The ICSP interface allows re-flashing via RB6/RB7 without removing the chip from the breadboard. Compared to the ATmega328P used in Arduino, the PIC16F84A has less memory but a simpler toolchain (MPLAB X + PICKit3), making it ideal for teaching register-level programming, interrupt handling, and Watchdog Timer concepts without abstraction layers.
Recommended
Legacy Industrial Controller Retrofit
The PIC16F84A-04E/SO is frequently used to maintain and retrofit legacy industrial control equipment where the original PIC16F84A design must be preserved for firmware compatibility. Its Extended -40 C to +125 C temperature range (the "E" suffix) tolerates factory-floor thermal stress, and its 64-byte on-chip EEPROM with 1M erase/write cycles typical provides non-volatile storage for calibration coefficients and setpoints without external serial EEPROM. The 18-SOIC surface-mount package supports automated pick-and-place assembly for production volumes, while the proven Watchdog Timer with independent on-chip RC oscillator catches firmware lock-ups in unattended installations. Replacing this part on a legacy PCB is straightforward because the pinout has remained stable across all PIC16F84A speed grades.
Recommended
Automotive Interior Accessory Module
Automotive interior accessories such as ambient lighting controllers, seat-position memory modules, and HVAC flap positioners often use the PIC16F84A-04E/SO because its Extended -40 C to +125 C temperature grade survives cabin thermal cycling. The 13 I/O pins are sufficient to read several rotary encoder inputs (for HVAC knob positions) and drive multiple low-side MOSFETs for LED strings, while the on-chip 8-bit Timer0 with 10-bit programmable prescaler handles debounce-free quadrature decoding. The 4 MHz internal-execution speed (5 MIPS peak) is more than adequate for slow control loops in the 10-100 Hz range typical of body electronics. However, note that the PIC16F84A-04E/SO is NOT AEC-Q100 qualified; for true automotive grade choose a Q1-suffixed PIC16F variant.
Recommended
Low-Cost Consumer Appliance Control
Small consumer appliances such as coffee makers, bread machines, electric kettles, and simple air purifiers use the PIC16F84A-04E/SO as a cost-optimized control MCU. Its 1.75 KB Flash holds the state machine, button de-bounce logic, and timing routines for the appliance, while the 64-byte EEPROM remembers user settings (last brew strength, favorite temperature). The 13 I/O pins are adequate for a 4x4 keypad matrix, a multiplexed 7-segment display, and a relay-driver output. At qty-1000 distributor pricing of approximately $2.45 USD as of 2026-09-21, this MCU fits the aggressive BOM targets of sub-$30 retail appliances. Designers should use the Watchdog Timer to recover from power-line glitches common in consumer environments.
Recommended
Remote Sensor Node with Polled Sampling
The PIC16F84A-04E/SO is suitable for non-real-time remote sensor nodes that wake periodically, take a measurement, transmit a packet, and return to sleep. Its 4 MHz active-mode speed is fast enough to service a UART-based radio modem (e.g., a 9600 baud link) while consuming only milliamps, and the on-chip EEPROM can log a few hundred sensor readings for batch upload. The 13 I/O pins connect a digital sensor (e.g., DS18B20 one-wire temperature), an LED status indicator, and a UART modem. A 32.768 kHz external crystal can be used on OSC1 if the application needs a real-time-clock tick. For new battery-powered sensor designs, prefer the PIC16F88 or PIC16LF1847 which have nanoWatt XLP sleep modes below 1 uA.
Recommended
In-Circuit Serial Programming (ICSP) Development Target
Many production engineering teams use the PIC16F84A-04E/SO as a known-good target board for validating ICSP programmers and production fixtures before deploying to higher-density PIC16 and PIC18 production parts. Because the entire PIC16F84A family uses the same RB6/PGC and RB7/PGD ICSP pin pair in the 18-SOIC package, a PIC16F84A-04E/SO fixture can verify timing margins for PICKit 3, PICKit 4, ICD 4, and MPLAB Snap programmers. Its 1.75 KB Flash also gives enough headroom for a self-test firmware image that exercises I/O toggling, EEPROM read/write, and Watchdog reset recovery - the three most critical production-line tests. Many contract manufacturers standardize on this exact MPN as their ICSP validation vehicle.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F84A-04E/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F84A-04I/SO | PIC16F84A-04/SO | PIC16F84A-20/SO | PIC16F84A-10/SO |
|---|---|---|---|---|---|
| Package | 18-SOIC | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core Speed (Max) | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 10 MHz |
| Operating Temperature | -40 C to +125 C (Extended) | -40 C to +85 C (Industrial) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial typical) | -40 C to +85 C (Industrial typical) |
| Flash Program Memory | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) |
| SRAM | 68 bytes | 68 bytes | 68 bytes | 68 bytes | 68 bytes |
| EEPROM | 64 bytes | 64 bytes | 64 bytes | 64 bytes | 64 bytes |
| Number of I/O Pins | 13 | 13 | 13 | 13 | 13 |
| RoHS Compliance | Compliant | Compliant | Compliant | Compliant | Compliant |
Key Differentiators
- Extended -40 C to +125 C temperature grade in surface-mount 18-SOIC (vs PIC16F84A-04I/SO)
- Speed-grade overdrive capability at same cost and package (vs PIC16F84A-10/SO)
- Same die as PIC16F628A but simpler peripheral set (vs PIC16F628A-I/SS)
Design Notes
Estimated: at 4 MHz active mode the PIC16F84A draws approximately 4-6 mA at 5 V from VDD. Place a 100 nF (0.1 uF) decoupling capacitor as close as possible (within 5 mm) between VDD (pin 14) and VSS (pin 5), with a second 10 uF bulk capacitor near the regulator output. The VDD supply must remain within 2.0 V to 5.5 V for the Extended temp grade; exceeding 5.5 V will damage the part. For battery applications consider a 3.3 V LDO such as MCP1700 to extend battery life.
Place the MCLR pull-up resistor (typically 10 kohm to VDD) and the MCLR decoupling capacitor (100 nF to ground) within 5 mm of pin 4. The MCLR pin has a Schmitt trigger input and should NOT be left floating - a floating MCLR can cause spurious resets in noisy environments. The ICSP clock (PGC, pin 12) and data (PGD, pin 13) lines should be routed with minimal stubs and a 4.7 kohm pull-down on PGD if the ICSP connector is removable, to prevent in-circuit noise from triggering programming mode inadvertently.
Do not assume the PIC16F84A-04E/SO has an internal oscillator - it requires an external crystal, ceramic resonator, or RC network on OSC1/OSC2. For HS mode (high-speed crystal, >4 MHz) the -04 grade is too slow; use the -20 grade for >4 MHz oscillator frequencies. RA4 is an open-drain output that requires an external pull-up resistor if used as a digital output. Watchdog Timer must be either explicitly enabled in CONFIG register or explicitly disabled in firmware - the default factory setting has WDT enabled, which can cause unexpected resets in code paths that exceed the WDT period.
Keep crystal traces (OSC1, OSC2) short and symmetric, with a ground guard ring if possible. The crystal load capacitors (typically 15-33 pF for a 4 MHz AT-cut crystal) must be sized per the crystal manufacturer's CL specification using the formula CL = (C1 * C2) / (C1 + C2) + Cstray. With Cstray ~5 pF, two 22 pF caps yield a CL around 16 pF - suitable for most 4 MHz crystals. For RC oscillator mode, the timing resistor on OSC2 should be a precision (1 %) metal-film type to maintain frequency accuracy.
Compliance Information
RoHS compliant per Microchip product page and DigiKey listing. The -04E/SO is NOT AEC-Q100 qualified - for true AEC-Q100 automotive grade use a Q1-suffixed PIC16F variant. Reach and conflict-minerals compliance status inferred from Microchip's standard corporate compliance program.