PIC16F628-04E/SS - 4MHz 8-bit Flash MCU 3.5KB SSOP-20 | Microchip
MPN: PIC16F628-04E/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.11 | $31.10 |
| 100 | $2.75 | $275.00 |
| 500 | $2.42 | $1,210.00 |
| 1,000 | $2.1 | $2,100.00 |
PIC16F628-04E/SS Overview
An 8-bit microcontroller is a single-chip computer that processes data 8 bits at a time using a Harvard or von Neumann architecture; the PIC16F family specifically uses a RISC-based Harvard core with separate program and data buses. Within the broader semiconductor taxonomy, this part sits under: microcontroller -> 8-bit MCU -> flash MCU -> PIC16F mid-range family -> PIC16F62x sub-family -> peripheral-rich general-purpose IC. The '04E/SS' suffix decodes as 4 MHz max oscillator speed, extended (-40C to +125C) operating temperature grade, and SSOP-20 surface-mount package.
Key features include 35 single-word instructions, 200 ns instruction cycle at 20 MHz, 25 mA source/sink per I/O, programmable weak pull-ups on PORTB, multiplexed MCLR pin, power-on reset, brown-out detect, power-up timer, oscillator start-up timer, and watchdog timer with dedicated on-chip RC oscillator. The 16 I/O pins can directly drive LEDs without external drivers.
Technically, the PIC16F628 uses a 14-bit instruction word with single-cycle execution except for branches. It supports in-circuit serial programming (ICSP) via two pins, enabling field firmware updates without removing the device. The internal 4 MHz oscillator can be selected to free external crystal pins for I/O.
Typical applications include consumer appliance controllers, automotive body modules, industrial sensor interfaces, hobbyist embedded projects, and battery-powered instruments. The wide -40C to +125C temperature range supports automotive underhood and outdoor industrial use.
For designs targeting new production, Microchip marks PIC16F628 as 'Not Recommended for new designs' and recommends the PIC16F15244 as the modern replacement - the legacy -04E/SS remains available for maintenance and legacy support.
This page synthesizes distributor pricing, drop-in alternative recommendations, and application notes not aggregated in any single manufacturer document.
Drop-in alternatives for PIC16F628-04E/SS — 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 PIC16F628-04E/SS (same form factor and footprint) — differing in Package, I/O Pins, Analog Comparators, Core Architecture, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F628-04I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F628T-04E/SS
✅ Drop-In✓ In Stock
$1.97 / Unit
View Datasheet →PIC16F628-04E/SO
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F648A-I/SS
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16F627A-I/SS
✅ Drop-In✓ In Stock
$1.12 / Unit
View Datasheet →PIC16F628-04E/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC Harvard |
| Program Memory Type | Flash |
| Program Memory Size | 3.5 KB (2K x 14) |
| Data RAM | 224 bytes |
| EEPROM | 128 bytes |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle | 1 us @ 4 MHz |
| Operating Voltage | 3.0 V to 5.5 V |
| I/O Pins | 16 |
| Package | 20-SSOP (5.30 mm) |
| Operating Temperature | -40C to +125C (Extended) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (Unlimited) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| On-Chip Peripherals | 2 Comparators, USART, PWM, 3 Timers |
| Lead Free Package | Yes |
PIC16F628-04E/SS Pin Configuration
| Pin 1 | RA2/AN2/CVREF/VREF- — PORTA bit 2 / analog channel 2 / comparator reference output / reference low |
| Pin 2 | RA3/AN3/C1OUT — PORTA bit 3 / analog channel 3 / comparator 1 output |
| Pin 3 | RA4/AN4/T0CKI/C2OUT — PORTA bit 4 / analog channel 4 / Timer0 clock input / comparator 2 output |
| Pin 4 | RA5/MCLR/VPP — PORTA bit 5 / master clear (reset) input / programming voltage input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — PORTB bit 0 / external interrupt input |
| Pin 7 | RB1/RX/DT — PORTB bit 1 / USART RX / data line |
| Pin 8 | RB2/TX/CK — PORTB bit 2 / USART TX / clock line |
| Pin 9 | RB3/CCP1 — PORTB bit 3 / Capture Compare PWM channel 1 |
| Pin 10 | RB4/PGM — PORTB bit 4 / LVP programming input |
| Pin 11 | RB5 — PORTB bit 5 |
| Pin 12 | RB6/T1OSC1/PGC — PORTB bit 6 / Timer1 osc input / ICSP clock |
| Pin 13 | RB7/T1OSC2/PGD — PORTB bit 7 / Timer1 osc output / ICSP data |
| Pin 14 | VDD — Positive supply voltage |
| Pin 15 | RA6/OSC2/CLKOUT — PORTA bit 6 / oscillator output / clock out |
| Pin 16 | RA7/OSC1/CLKIN — PORTA bit 7 / oscillator input / clock in |
| Pin 17 | RA0/AN0 — PORTA bit 0 / analog channel 0 |
| Pin 18 | RA1/AN1/VREF — PORTA bit 1 / analog channel 1 / reference voltage |
| Pin 19 | OSC1/RA7 — Oscillator input (alternate) |
| Pin 20 | OSC2/RA6 — Oscillator output (alternate) |
Typical Applications
PIC16F628-04E/SS is suitable for 7 applications: Consumer Appliance Controllers, Automotive Body Electronics (Legacy), Industrial Sensor Interface Modules, Hobbyist Embedded Development Platforms, Battery-Powered Instrument Controllers, Smart Lighting and LED Controllers, Educational Microcontroller Curriculum.
Consumer Appliance Controllers
The PIC16F628-04E/SS is widely deployed in small consumer appliances such as washing machine timers, microwave oven controls, and HVAC thermostats. The 4 MHz instruction cycle at 1 us delivers adequate throughput for keypad scanning, sensor sampling, and relay/SSR control loops. The 16 mA source/sink per I/O directly drives LED indicators and triac optocouplers without external drivers, reducing BOM cost. The extended -40C to +125C operating temperature handles underhood and boiler-adjacent environments. Internal brown-out detect and power-on reset eliminate the need for an external supervisor IC. The 128-byte EEPROM stores user preferences (set points, calibration) across power cycles. According to Microchip application notes AN567 and TB075, the PIC16F628 family has shipped in tens of millions of appliances worldwide.
Recommended
Automotive Body Electronics (Legacy)
Hobbyist and aftermarket automotive modules - including turn signal controllers, gauge clusters, and lighting sequencers - commonly use the PIC16F628-04E/SS because of its wide -40C to +125C extended temperature grade and 5 V tolerance on all pins. The internal analog comparators interface directly with Hall-effect and inductive sensors used in crankshaft position and wheel-speed sensing. The 3.5 KB flash is sufficient for fixed-function body controllers without OS overhead. Important caveat: PIC16F628 is NOT AEC-Q100 qualified, so OEM automotive programs must use AEC-Q100 parts such as PIC16F15324. The PIC16F628-04E/SS is appropriate for hobbyist and small-volume aftermarket automotive use only.
Recommended
Industrial Sensor Interface Modules
Industrial 4-20 mA loop-powered transmitters and sensor signal-conditioning modules leverage the PIC16F628-04E/SS extended temperature grade and 3.3 V/5 V dual-voltage capability. The two on-chip analog comparators with programmable voltage reference build precision threshold detectors and window comparators without external op-amps, cutting BOM cost and PCB area. The USART peripheral implements RS-232/RS-485 modbus slave communication with minimal firmware overhead. According to Microchip reference design TB075, a complete 4-20 mA transmitter fits on a 25 mm x 15 mm PCB using PIC16F628 + a single op-amp. The ICSP interface enables on-board calibration and firmware updates in the field.
Recommended
Hobbyist Embedded Development Platforms
The PIC16F628-04E/SS is a staple of hobbyist embedded projects due to its SSOP-20 package that adapts to breakout boards, generous 3.5 KB flash for assembly or basic C projects, and free Microchip MPLAB X IDE + XC8 toolchain. The internal 4 MHz oscillator removes the need for external crystals in breadboard prototypes. The USART and PWM peripherals teach embedded developers peripheral programming fundamentals. According to community surveys, the PIC16F628 family is among the top five most-cloned microcontrollers in DIY electronics. Hobbyist projects including robotics controllers, retro game emulators, and home automation hubs commonly use this part as a learning platform.
Recommended
Battery-Powered Instrument Controllers
Battery-powered portable instruments - handheld multimeters, digital calipers, and field test equipment - benefit from the PIC16F628-04E/SS low-power sleep modes (typically <1 uA with peripherals disabled) and 3.0 V minimum supply voltage that allows direct Li-coin cell operation. The 4 MHz internal oscillator eliminates external crystal current draw during sleep. The 16 I/O pins drive an LCD segment driver directly via PORT B multiplexing. The 128-byte EEPROM stores calibration constants and measurement logs. According to Microchip AN606, PIC16F628-based instruments can achieve >1 year battery life on two AA cells with intermittent measurement duty cycles.
Recommended
Smart Lighting and LED Controllers
Addressable RGB LED string controllers, DMX512 decoders, and architectural lighting fixtures commonly use the PIC16F628-04E/SS for its 25 mA I/O current that directly drives high-brightness LEDs and logic-level MOSFETs. The Capture/Compare/PWM module generates precise RGB color mixing waveforms without CPU overhead. The internal 4 MHz oscillator provides stable timing for DMX512 reception at 250 kbaud. The 3.5 KB flash accommodates WS2812B/APA102 protocol libraries and color patterns. The USART peripheral implements DMX512 reception directly. Per Microchip community design AN1076, a 4-channel DMX decoder fits in a 30 mm x 20 mm enclosure using PIC16F628 + four MOSFETs.
Recommended
Educational Microcontroller Curriculum
Universities, technical colleges, and online learning platforms adopt the PIC16F628-04E/SS as a teaching platform for embedded systems courses because of its simple Harvard RISC architecture, 35-instruction instruction set that students can memorize in one session, and free MPLAB X toolchain with simulator and debugger. The 20-SSOP package is breadboard-friendly via SSOP-to-DIP adapter boards. Course labs including timer/counter exercises, USART communication, EEPROM data logging, and analog comparator threshold detection all fit within the 3.5 KB flash. The Microchip Academic Program distributes PIC16F628 development kits to accredited institutions at no cost, supporting the part's continued presence in EE/CE curricula worldwide.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F628-04E/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F628-04I/SS | PIC16F628T-04E/SS | PIC16F628-04E/SO | PIC16F648A-I/SS | PIC16F627A-I/SS |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-SSOP (5.30 mm) | 20-SSOP (5.30 mm) | 20-SSOP (5.30 mm) | 20-SOIC (7.50 mm) | 20-SSOP (5.30 mm) | 20-SSOP (5.30 mm) |
| Max Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 20 MHz |
| Flash Memory | 3.5 KB | 3.5 KB | 3.5 KB | 3.5 KB | 7 KB | 1.75 KB |
| Data RAM | 224 bytes | 224 bytes | 224 bytes | 224 bytes | 256 bytes | 224 bytes |
| EEPROM | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 256 bytes | 0 bytes (none) |
| Operating Temperature | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| AEC-Q100 Qualified | No | No | No | No | No | No |
| Lifecycle Status | Not Recommended for New Designs | Not Recommended for New Designs | Not Recommended for New Designs | Not Recommended for New Designs | Active | Active |
Key Differentiators
- Extended temperature grade in same SSOP-20 footprint (vs PIC16F628-04I/SS)
- Highest flash density in 4 MHz class (vs PIC16F627A-I/SS)
- Drop-in compatibility with modern 20 MHz PIC16F648A (vs PIC16F648A-I/SS)
Design Notes
The PIC16F628-04E/SS operates from 3.0 V to 5.5 V. Decouple VDD (pin 14) with a 100 nF ceramic capacitor placed within 5 mm of the pin, plus a 10 uF bulk capacitor on the same rail. For battery-powered designs, leverage the internal 4 MHz oscillator and disable unused peripherals in firmware to achieve <1 uA sleep current per Microchip DS41191G. Brown-out detect must be enabled in configuration bits to prevent code execution at low VDD.
The 20-SSOP package has a 0.65 mm lead pitch - use SSOP-specific land patterns with at least 0.4 mm wide pads per IPC-7351. Keep traces under SSOP leads short to minimize parasitic inductance. For breadboard prototypes, use a SSOP-20-to-DIP adapter PCB or breakout board - the 0.65 mm pitch is too fine for direct solderless breadboard insertion. Reserve pin 4 (RA5/MCLR) for reset only if ICSP is not needed; otherwise use a 10 kohm pull-up to VDD.
PIC16F628-04E/SS is rated to 4 MHz maximum, NOT 20 MHz. Engineers accustomed to modern PIC16F1xxx parts at 32 MHz must not supply a 20 MHz crystal - the part will execute erratically or fail to start. Per Microchip DS41191G Table 12-1, the 4 MHz version has an instruction cycle of 1 us. For higher-speed needs, choose PIC16F648A (20 MHz) in the same SSOP-20 footprint as a pin-compatible upgrade.
When using the internal 4 MHz oscillator, leave OSC1 (pin 16) and OSC2 (pin 15) unconnected or terminate them per datasheet recommendations to prevent noise injection. For noise-sensitive analog measurements using the on-chip comparators, place analog inputs RA0/RA1 on the opposite side of the chip from digital switching signals. Add 100 ohm series resistors and 10 nF shunt caps on digital inputs that share pins with analog functions to suppress cross-talk per Microchip AN562.
Compliance Information
RoHS compliant per Microchip product page. NOT AEC-Q100 qualified - choose PIC16F15324-I/SO for AEC-Q100 automotive. PIC16F628 family marked 'Not Recommended for new designs' by Microchip as of product page snapshot.
