PIC16C55T-LPI/SS - 8-Bit 40MHz OTP MCU 28-SSOP | Microchip
MPN: PIC16C55T-LPI/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.55 | $25.50 |
| 100 | $2.2 | $220.00 |
| 500 | $1.95 | $975.00 |
| 1,000 | $1.75 | $1,750.00 |
PIC16C55T-LPI/SS Overview
The PIC® 16C microcontroller family uses a Harvard-architecture RISC CPU with a reduced 33-instruction set and 12-bit-wide instructions that deliver 2:1 code compression over competing 8-bit architectures in the same price tier. The "PIC" acronym (Peripheral Interface Controller) reflects its origins as a peripheral interface IC, and the family has become a foundational building block in embedded systems. The PIC16C5X series sits at the entry-level of the PIC16 hierarchy, offering fully static operation, low power consumption, and OTP-based code storage for low-volume production runs.
Key features include 20 bidirectional digital I/O pins, on-chip Power-On Reset to initialize the device cleanly at power-up, a Watchdog Timer for runaway code recovery, and an integrated oscillator with selectable clock modes (RC, LP, XT, HS) for design flexibility. The 28-SSOP package (5.30 mm body width, 0.65 mm pitch) provides a compact footprint suitable for space-constrained PCB layouts while maintaining compatibility with standard reflow processes. Operating voltage spans 2.5V to 6.0V, enabling compatibility with both 3.3V and 5V logic rails.
Typical applications include low-cost consumer appliances, automotive body controllers, industrial sensor interfaces, white-goods motor control, and battery-powered instruments where small code footprint and deterministic execution are paramount. The PIC16C55T's mature toolchain (MPLAB, MPASM) and broad third-party support make it well suited for legacy designs and maintenance of installed-base products.
When designing with this device, allocate adequate decoupling (100 nF ceramic adjacent to VDD/VSS) and consider the OTP programming requirement - code must be committed during manufacturing, so development flows typically use a flash-based PIC16F5X sibling during prototyping. Pin 1 dot orientation must be verified against the SSOP notch mark during board layout.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, enabling faster component evaluation and PCB reuse decisions.
Drop-in alternatives for PIC16C55T-LPI/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 PIC16C55T-LPI/SS (same form factor and footprint) — differing in Program Memory Size, Operating Temperature, Package, Core Architecture, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-LPI/SS
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC16F57-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55T-LPI/SO
✅ Drop-In✓ In Stock
$2.49 / Unit
View Datasheet →PIC16C55T-HSI/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C554-04I/SS
✅ Drop-In✓ In Stock
$1.45 / Unit
View Datasheet →PIC16C558-20/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C55T-LPI/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Core Speed | 40 MHz maximum |
| Program Memory Type | OTP (One-Time-Programmable) EPROM |
| Program Memory Size | 768 bytes (512 x 12 bits) |
| RAM Size | 24 bytes (24 x 8) |
| Number of I/O Pins | 20 |
| Package | 28-pin SSOP (5.30 mm width) |
| Mounting Type | Surface Mount |
| Supply Voltage Range | 2.5 V to 6.0 V |
| Operating Temperature | -40C to +85C (industrial grade, LP) |
| Instruction Set | 33 instructions, 12-bit wide |
| Peripherals | Power-On Reset (POR), Watchdog Timer (WDT) |
| Oscillator Modes | RC, LP, XT, HS |
PIC16C55T-LPI/SS Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O port A bit 3 |
| Pin 3 | RA4/T0CKI — Bidirectional I/O port A bit 4 / Timer0 clock input |
| Pin 4 | MCLR/VPP — Master clear reset (active low) / Programming voltage input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Bidirectional I/O port B bit 0 / External interrupt |
| Pin 7 | RB1 — Bidirectional I/O port B bit 1 |
| Pin 8 | RB2 — Bidirectional I/O port B bit 2 |
| Pin 9 | RB3 — Bidirectional I/O port B bit 3 |
| Pin 10 | RB4 — Bidirectional I/O port B bit 4 |
| Pin 11 | RB5 — Bidirectional I/O port B bit 5 |
| Pin 12 | RB6 — Bidirectional I/O port B bit 6 |
| Pin 13 | RB7 — Bidirectional I/O port B bit 7 |
| Pin 14 | VSS — Ground reference |
| Pin 15 | OSC1/CLKIN — Oscillator crystal input / External clock input |
| Pin 16 | OSC2/CLKOUT — Oscillator crystal output / Clock output (F4 mode) |
| Pin 17 | RC0 — Bidirectional I/O port C bit 0 |
| Pin 18 | RC1 — Bidirectional I/O port C bit 1 |
| Pin 19 | RC2 — Bidirectional I/O port C bit 2 |
| Pin 20 | RC3 — Bidirectional I/O port C bit 3 |
| Pin 21 | RC4 — Bidirectional I/O port C bit 4 |
| Pin 22 | RC5 — Bidirectional I/O port C bit 5 |
| Pin 23 | RC6 — Bidirectional I/O port C bit 6 |
| Pin 24 | RC7 — Bidirectional I/O port C bit 7 |
| Pin 25 | VDD — Positive supply voltage (2.5V to 6.0V) |
| Pin 26 | NC — Not connected (per datasheet) |
| Pin 27 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 28 | RA1 — Bidirectional I/O port A bit 1 |
Typical Applications
PIC16C55T-LPI/SS is suitable for 6 applications: Consumer Appliance Control, Industrial Sensor Interface, Automotive Body Electronics, White-Goods Motor Control, Battery-Powered Instruments, Legacy Embedded System Maintenance.
Consumer Appliance Control
The PIC16C55T-LPI/SS suits low-cost consumer appliance controllers - washing machines, microwave ovens, and dishwasher user interfaces - where deterministic RISC execution and small code footprint matter. Its 768-byte OTP program memory holds typical appliance state machines (button debouncing, timer sequencing, relay control), while 20 I/O pins drive segment displays, keypads, and triac/SCR gates directly. The 40 MHz core executes the 33-instruction PIC set in single cycles, enabling responsive user-interface loops without RTOS overhead. The 2.5V-6.0V supply range accepts both 3.3V and 5V rails from simple linear regulators.
Recommended
Industrial Sensor Interface
Factory automation sensor nodes - proximity switches, limit detectors, simple counters - use the PIC16C55T-LPI/SS to read digital inputs, debounce mechanical contacts, and drive indicator LEDs or relay outputs. The integrated Watchdog Timer recovers from ESD-induced code faults on the factory floor, while Power-On Reset ensures deterministic startup after brown-out events common in industrial 24V supplies. The industrial temperature grade (-40C to +85C) tolerates cabinet environments. 20 I/O channels accommodate multi-sensor conditioning and HMI feedback on a single SSOP-28 footprint.
Recommended
Automotive Body Electronics
Body-control modules for window lifters, mirror adjusters, seat controllers, and lighting drivers leverage the PIC16C55T-LPI/SS for cost-optimized 8-bit processing where the industrial temperature grade is acceptable for cabin environments. The PIC12-bit instruction set compresses typical relay-sequencing code into 768 bytes, leaving room for diagnostic state machines and watchdog-driven safety checks. The 20 I/O pins connect directly to automotive-grade switches and power MOSFETs via gate drivers, while the SSOP-28 footprint fits space-constrained door-module PCBs.
Recommended
White-Goods Motor Control
Small motor controllers in fans, pumps, and HVAC dampers use the PIC16C55T-LPI/SS to generate PWM waveforms and read tachometer feedback in BLDC or single-phase AC induction systems. The 40 MHz core and predictable interrupt latency (no pipeline stalls) deliver deterministic commutation timing without DSP overhead. The 20 I/O pins route to gate drivers, current-sense amplifiers, and Hall-effect sensor inputs; the integrated WDT protects against motor-induced EMI causing code lockup. The 2.5V-6.0V supply operates from common 5V motor-rail regulators.
Recommended
Battery-Powered Instruments
Portable measurement devices - handheld multimeters, thermometers, environmental loggers - benefit from the PIC16C55T-LPI/SS low-power CMOS process and 2.5V minimum supply, which enables direct battery operation from 2xAA or single Li-ion cells. The 24-byte RAM accommodates small measurement buffers, while 768 bytes of OTP holds calibration tables and UI state machines. Industrial temperature grade ensures stable operation across outdoor temperature swings. Sleep-mode-friendly code patterns (WDT-based wakeups) extend battery life beyond what higher-end MCUs achieve.
Recommended
Legacy Embedded System Maintenance
Industrial installations with installed PIC16C55T-LPI/SS base - assembly line controllers, legacy PLCs, and OEM equipment - use this part for direct replacement of failed units during maintenance cycles. The OTP memory guarantees code immutability for safety-certified applications (no field firmware drift), while the mature PIC16C5X toolchain (MPLAB IDE, MPASM assembler, ICD debuggers) allows production engineers to recompile identical firmware from archived source. Maintaining the legacy footprint avoids costly PCB re-spin and certification re-validation.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55T-LPI/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-LPI/SS | PIC16F57-I/SS | PIC16C554-04I/SS | PIC16C558-20/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SSOP | 28-SSOP (same) | 28-SSOP (same) | 28-SSOP (same) | 28-SSOP (same) |
| Program Memory | 768 bytes (512 x 12) OTP | 768 bytes OTP (same) | 3.5 KB (2K x 14) Flash | 1.75 KB (1K x 14) OTP | 3.5 KB (2K x 14) OTP |
| Memory Type | OTP EPROM | OTP EPROM (same) | Flash (reprogrammable) | OTP EPROM | OTP EPROM |
| RAM Size | 24 bytes | 24 bytes (same) | 72 bytes | 80 bytes | 128 bytes |
| Maximum Core Speed | 40 MHz | 40 MHz (same) | 20 MHz | 20 MHz | 20 MHz |
| I/O Pins | 20 | 20 (same) | 20 (same) | 20 (same) | 20 (same) |
| Supply Voltage | 2.5V to 6.0V | 2.5V to 6.0V (same) | 2.0V to 5.5V | 2.5V to 6.0V | 2.5V to 6.0V |
| Lifecycle Status | Obsolete | Obsolete | Active | Obsolete | Obsolete |
Key Differentiators
- OTP memory guarantees firmware immutability for safety-certified applications (vs PIC16F57-I/SS)
- Tape-and-reel packaging optimized for high-volume automated assembly (vs PIC16C55-LPI/SS)
- 40 MHz core speed delivers 10 MIPS for tight control loops (vs PIC16C558-20/SS)
Design Notes
Decouple VDD (pin 25) with a 100 nF ceramic capacitor placed within 5 mm of the package, returning to VSS (pin 14) with the shortest possible trace. For battery-powered designs drawing <2 mA average, the PIC16C5X sleep mode reduces current to under 4 uA - verify with the LP process variant. Bulk capacitance of 4.7-10 uF near the regulator improves immunity to motor-induced supply transients common in appliance designs.
The PIC16C5X OTP memory cannot be erased or reprogrammed - any code bug discovered after programming requires a new device. During development, always prototype with a flash-based sibling (PIC16F57-I/SS, PIC16F59) and migrate to PIC16C55T only after firmware is locked. The /MCLR pin must be pulled high through a 10 kohm resistor for normal operation; leaving it floating prevents startup. Oscillator mode (RC/LP/XT/HS) must match the actual crystal or resonator choice or operation will be unreliable.
The 28-SSOP has a 0.65 mm lead pitch requiring reflow profiles consistent with JEDEC J-STD-020. Recommended pad geometry follows IPC-7351 SSOP-28 land pattern with 0.40 mm wide pads and 0.20 mm mask openings. Place the decoupling capacitor land between VDD (pin 25) and VSS (pin 14) on the top layer to minimize loop area. Avoid routing high-frequency traces beneath the SSOP - the SSOP-28 has no exposed pad and cannot dissipate more than ~500 mW without exceeding the 150C junction limit.
Pin 1 identification on the 28-SSOP relies on the dot or notch mark on the package - typical SSOP packaging places the dot on the upper-left when the notch is on the left. With pin 1 at upper-left, pins count counter-clockwise around the package: 1-14 along the left edge top-to-bottom, then 15-28 along the right edge bottom-to-top. Always confirm with the manufacturer pinout diagram; reversed orientation will short VDD to VSS and destroy the device instantly.
Compliance Information
The 'I' suffix in PIC16C55T-LPI/SS indicates Pb-free finish per Microchip ordering nomenclature. RoHS and REACH compliance assumed for industrial-grade LP variants. AEC-Q100 not applicable for industrial-grade MCU; choose PIC16F716 or PIC16F57-Q1 for automotive. Halogen-free status not confirmed in available data.
