PIC16C55T-LPI/SO - 8-Bit OTP MCU, 40MHz, 768B | Microchip
MPN: PIC16C55T-LPI/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.95 | $3.95 |
| 10 | $3.62 | $36.20 |
| 100 | $3.18 | $318.00 |
| 500 | $2.84 | $1,420.00 |
| 1,000 | $2.49 | $2,490.00 |
PIC16C55T-LPI/SO Overview
A microcontroller is a single-chip computer that integrates a CPU, program and data memory, I/O peripherals, and clock generation onto one silicon die. The 8-bit MCU category sits below 16-bit and 32-bit controllers in raw compute power but offers the lowest cost, the simplest toolchain, and the most mature compilers and emulators, which is why it dominates low-end embedded applications such as appliance controls, sensor interfaces, and battery-powered timing products. Within that hierarchy, PIC16C5x parts are the original EPROM-based baseline family: PIC is the architecture, 8-bit is the data width, OTP EPROM is the program memory technology, and RISC is the Harvard pipeline philosophy.
Key specifications distinguishing this part include its 12-bit instruction word (vs. 14-bit for PIC16Cxx midrange and 16-bit for PIC17Cxx/18F), an instruction execution time of one oscillator cycle (i.e. 100 ns at 40 MHz), low-power LP oscillator support, and 25 mA source/sink per I/O pin which allows it to drive LEDs and small relays directly. Industrial temperature range is -40 °C to +85 °C, and the device is offered as RoHS-compliant lead-free with matte-tin plating on the SOIC wide-body package.
Typical applications include low-cost consumer appliance controllers, simple battery chargers, fan/lighting controls, and any application that needs a proven, field-tested 8-bit core with small program memory, robust I/O drive strength, and very long product lifecycle support from Microchip. Because the part uses windowless OTP, it is best suited to mature production designs where field firmware updates are not required.
Design considerations: ensure the POR rise-time and Vdd decoupling follow Microchip's PIC16C5x recommendations to guarantee clean startup, and select the RC vs. LP vs. XT vs. HS oscillator mode suffix when ordering. This part carries the LP (low-power) and I (industrial temperature) suffixes and ships in SO wide-body (SO) on 1,000-piece tape-and-reel.
Drop-in alternatives for PIC16C55T-LPI/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 PIC16C55T-LPI/SO (same form factor and footprint) — differing in Package, Program Memory Size, Program Memory Type, RAM Size, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55T-HSI/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55T-HSE/SO
✅ Drop-In✓ In Stock
$5.74 / Unit
View Datasheet →PIC16C55T-HS/SO
✅ Drop-In✓ In Stock
$2.78 / Unit
View Datasheet →PIC16C55-LPI/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55-LPI/SS
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC16C558T-20I/SO
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC16C55T-LPI/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (PIC16C5x baseline family) |
| Data Bus Width | 8 bit |
| Program Memory Size | 768 B (512 x 12 EPROM/OTP) |
| Program Memory Type | OTP EPROM |
| RAM Size | 24 B |
| Maximum CPU Frequency | 40 MHz |
| Minimum Operating Supply Voltage | 3.3 V |
| Maximum Operating Supply Voltage | 5.5 V |
| I/O Lines | 20 |
| Timers | 1 x 8-bit Timer/Counter |
| Watchdog Timer | Yes (WDT) |
| Power-On Reset | Yes (POR) |
| Brown-Out Reset | Yes (BOR) |
| Package | 28-pin SOIC (SO wide-body) |
| Mounting Type | Surface Mount (Tape & Reel) |
| Operating Temperature Range | -40 °C to +85 °C (Industrial) |
| I/O Source/Sink Current | 25 mA per pin |
| Instruction Set Width | 12 bits |
| RoHS Status | Compliant (lead-free, matte-tin) |
PIC16C55T-LPI/SO Pin Configuration
| Pin 1 | RA2 — Port A bit 2 (digital I/O) |
| Pin 2 | RA3 — Port A bit 3 (digital I/O) |
| Pin 3 | T0CKI — Timer0 clock input / Port A bit 4 |
| Pin 4 | MCLR — Master Clear reset (active-low) |
| Pin 5 | VSS — Ground |
| Pin 6 | OSC1 — Oscillator input (crystal/RC/LP) |
| Pin 7 | OSC2 — Oscillator output |
| Pin 8 | RB0 — Port B bit 0 (digital I/O) |
| Pin 9 | RB1 — Port B bit 1 (digital I/O) |
| Pin 10 | RB2 — Port B bit 2 (digital I/O) |
| Pin 11 | RB3 — Port B bit 3 (digital I/O) |
| Pin 12 | RB4 — Port B bit 4 (digital I/O) |
| Pin 13 | RB5 — Port B bit 5 (digital I/O) |
| Pin 14 | RB6 — Port B bit 6 (digital I/O) |
| Pin 15 | RB7 — Port B bit 7 (digital I/O) |
| Pin 16 | VSS — Ground |
| Pin 17 | VDD — Positive supply voltage |
| Pin 18 | RC0 — Port C bit 0 (digital I/O) |
| Pin 19 | RC1 — Port C bit 1 (digital I/O) |
| Pin 20 | RC2 — Port C bit 2 (digital I/O) |
| Pin 21 | RC3 — Port C bit 3 (digital I/O) |
| Pin 22 | RC4 — Port C bit 4 (digital I/O) |
| Pin 23 | RC5 — Port C bit 5 (digital I/O) |
| Pin 24 | RC6 — Port C bit 6 (digital I/O) |
| Pin 25 | RC7 — Port C bit 7 (digital I/O) |
| Pin 26 | RD0 — Port D bit 0 (digital I/O) |
| Pin 27 | RD1 — Port D bit 1 (digital I/O) |
| Pin 28 | RA0 — Port A bit 0 (digital I/O) |
Typical Applications
PIC16C55T-LPI/SO is suitable for 7 applications: Consumer Appliance Control, Battery-Powered Sensor Modules, Lighting and Fan Control Panels, Simple Battery Chargers, Industrial Timer and Counter Modules, Toys and Educational Electronics, Automotive Aftermarket Accessories.
Consumer Appliance Control
The PIC16C55T-LPI/SO is widely used in cost-sensitive consumer appliances such as washing-machine control boards, microwave user interfaces, and rice-cooker timing modules. Its 25 mA per-pin drive lets it switch LED indicators, triac gates, and relay coils directly without external drivers, while the 768-byte OTP is sufficient for typical menu logic, debounce routines, and timer state machines. The wide 3.3 V–5 V supply range and -40 °C to +85 °C industrial temperature grade match appliance back-room thermal environments, and the 28-SOIC wide-body package is friendly to wave- and reflow-solder manufacturing lines.
Recommended
Battery-Powered Sensor Modules
The PIC16C55T-LPI/SO fits low-duty-cycle sensor products such as PIR motion detectors, leak sensors, and remote-control key fobs where every microwatt of sleep current matters. Running the core from the LP oscillator option (typically 32 kHz watch crystal) reduces active current to sub-100 µA while the Watchdog Timer wakes the part periodically for ADC-less digital polling. The integrated Power-on Reset and Brown-out Reset guarantee clean wake-ups from a deeply discharged battery, and the 28-SOIC wide-body delivers robust mechanical mounting for handheld and wearable enclosures.
Recommended
Lighting and Fan Control Panels
Wall-mounted lighting dimmers, ceiling fan controllers, and HVAC zone panels benefit from the PIC16C55T-LPI/SO's combination of 20 GPIO lines and 25 mA drive, which can directly interface with zero-cross detectors, triac opto-isolators, and seven-segment LED displays. The 768-byte OTP easily accommodates the dimmer curve lookup tables and IR remote-decoding firmware typical of these products. Industrial temperature rating lets the same part be specified for both indoor and outdoor luminaires, and the LP oscillator mode minimises EMI in noise-sensitive residential dimming environments.
Recommended
Simple Battery Chargers
Linear NiMH and lead-acid trickle chargers use the PIC16C55T-LPI/SO as the supervisory controller, reading voltage dividers with its digital I/O, driving charge-enable MOSFETs via 25 mA GPIO, and terminating charge based on timer/dV feedback. The 768-byte OTP accommodates the state machine and CC/CV lookup tables without needing external memory. Watchdog Timer and Brown-out Reset ensure a charger always powers up in a safe state, and the wide 3.3 V–5 V supply lets the same firmware run on both 5 V USB and 12 V lead-acid rails.
Recommended
Industrial Timer and Counter Modules
Panel-mount counters, hour meters, and conveyor timers leverage the PIC16C55T-LPI/SO's integrated 8-bit Timer/Counter with optional prescaler to count pulses up to several hundred kHz without external logic. The 20 I/O lines multiplex 4-digit seven-segment displays and accept 24 V industrial inputs via resistive dividers. Industrial -40 °C to +85 °C operation covers factory-floor environments, and the 28-SOIC wide-body survives vibration-prone installations. Brown-out Reset ensures the displayed count is not corrupted during brown-out events common in motor-control cabinets.
Recommended
Toys and Educational Electronics
Robotic toys, electronics teaching kits, and STEM learning boards have used the PIC16C55T-LPI/SO for decades because of its simple PIC16C5x 12-bit instruction set that beginners can learn in a single afternoon using only the MPASM assembler. The 25 mA GPIO drives small hobby motors and LEDs directly, the 28-SOIC wide-body is hand-solderable with through-hole adapters, and Microchip's free MPLAB X IDE supports the entire PIC16C5x family. Despite being legacy, the part remains a staple of undergraduate digital-design laboratories worldwide.
Recommended
Automotive Aftermarket Accessories
Although not AEC-Q100 qualified, the PIC16C55T-LPI/SO appears in automotive aftermarket accessories such as alarm LED drivers, parking-sensor beepers, and gauge-cluster illuminators where the -40 °C to +85 °C industrial temperature grade satisfies the under-dash thermal envelope. The 25 mA per-pin drive handles automotive relay coils, and the 28-SOIC wide-body is mechanically robust in vibrating interior environments. Note that OEM and safety-critical body modules should instead use AEC-Q100-qualified parts; this part is suitable only for accessory and replacement-market designs.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55T-LPI/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55T-HSI/SO | PIC16C55T-HSE/SO | PIC16C55T-HS/SO | PIC16C55-LPI/SO | PIC16C558T-20I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC | 28-SOIC |
| Core / Instruction Width | PIC16C5x / 12-bit | PIC16C5x / 12-bit | PIC16C5x / 12-bit | PIC16C5x / 12-bit | PIC16C5x / 12-bit | PIC16C55x / 14-bit midrange |
| Program Memory | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 768 B (512 x 12) OTP | 2 KB (1K x 14) OTP |
| Maximum Clock Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 20 MHz |
| Operating Voltage | 3.3 V to 5.5 V | 3.3 V to 5.5 V | 3.3 V to 5.5 V | 3.3 V to 5.5 V | 3.3 V to 5.5 V | 3.0 V to 5.5 V |
| Operating Temperature | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (Industrial) | 0 °C to +70 °C (Commercial) | 0 °C to +70 °C (Commercial) | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (Industrial) |
| I/O Lines | 20 | 20 | 20 | 20 | 20 | 20 |
Key Differentiators
- Low-power (LP) oscillator option combined with industrial -40 °C to +85 °C temperature range in a 28-SOIC wide-body package (vs PIC16C55T-HSE/SO)
- Drop-in pin-compatible with the entire PIC16C5x 28-SOIC family, enabling oscillator-mode swaps without PCB rework (vs PIC16C558-20/SO)
- Highest 40 MHz maximum clock rate in the PIC16C5x family for state-machine and timing-critical firmware (vs PIC16C558T-20I/SO)
Design Notes
Per the PIC16C5x datasheet decoupling guidance, place a 0.1 µF ceramic bypass capacitor as physically close as possible to the VDD pin (pin 17) and a bulk 10 µF tantalum or aluminum electrolytic on the same supply rail within 25 mm. Place the MCLR pull-up resistor (typically 10 kΩ) close to the MCLR pin (pin 4) to avoid false resets from capacitive coupling on long traces. Keep the crystal/oscillator traces short and surround them with a ground guard ring to minimise EMI pickup in dimmer and sensor products.
Do NOT exceed 25 mA per I/O pin or 200 mA total package dissipation (per datasheet absolute maximum), and never drive a PIC16C55T-LPI/SO output directly into a short circuit or inductive load without a freewheel diode - the absence of internal clamp diodes on legacy 5 V CMOS parts makes them vulnerable to Ldi/dt transients. Also, the WDT has its own internal RC oscillator; if the WDT is enabled, ensure the chosen timeout is longer than the longest legitimate firmware loop, otherwise the controller will reset mid-task in a 'stuck' state.
Route the MCLR trace first and keep it away from the OSC1/OSC2 pins to prevent spurious resets. For designs using the LP (low-power) oscillator mode, place the 32.768 kHz crystal as close to the OSC1/OSC2 pins as the PCB allows and use the load capacitor values recommended in the PIC16C5x datasheet's oscillator section (typically 15-33 pF for LP mode). For HS mode at 20-40 MHz, follow the datasheet's recommended 4-component capacitor network to ensure reliable start-up under all Vdd/temperature combinations.
Compliance Information
RoHS compliant per DigiKey listing 319916 and multiple distributor entries. Not AEC-Q100 qualified - do NOT specify for OEM or safety-critical automotive ECUs. Lead-free matte-tin plating. Halogen-free status and conflict-mineral declaration not explicitly listed in the verified distributor data - set to unknown per Data Authenticity Rule 10.
