PIC16C55T-XTE/SS - 8-bit OTP MCU, 4MHz, 28-SSOP | Microchip
MPN: PIC16C55T-XTE/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.92 | $5.92 |
| 10 | $5.33 | $53.30 |
| 100 | $4.74 | $474.00 |
| 500 | $4.26 | $2,130.00 |
| 1,000 | $3.79 | $3,790.00 |
PIC16C55T-XTE/SS Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory, data RAM, and integrated peripherals such as timers and I/O. Within the broader taxonomy, the PIC16C55 sits as: 8-bit microcontroller -> RISC microcontroller -> microcontroller -> embedded IC -> semiconductor. The PIC16C5X family specifically targets low-cost, high-volume applications where deterministic instruction execution and minimal external component count are valued over raw processing power.
Key features include 33 single-word instructions, a 12-bit instruction word width yielding 2:1 code compression versus competing 8-bit architectures, a Power-on Reset (POR), a Watchdog Timer (WDT) for reliable operation, and an 8-bit real-time timer/counter. The OTP program memory is one-time programmable, suitable for volume production where firmware is finalized and code updates are not expected in the field.
Architecturally, the PIC16C55 uses a Harvard-style RISC core with separate program and data buses, enabling most instructions to execute in a single instruction cycle (250 ns at 4 MHz). The CMOS process delivers low power consumption suitable for both battery-powered and line-powered equipment. The 28-SSOP footprint offers a compact 5.30 mm body width, ideal for space-constrained PCB layouts.
Typical applications include consumer appliance control, simple sensor interfaces, LED display drivers, low-end remote controls, and industrial timers where the combination of low cost, deterministic timing, and Microchip's mature toolchain (MPLAB) provides a fast time-to-market. The 4 MHz clock speed is sufficient for slow human-interface tasks but not for high-speed communication protocols.
When designing with this part, note that the PIC16C55 is an older EPROM-based architecture with no in-circuit debug capability. Designers should plan for a socketed programming adapter during development and verify the OTP write window with the chosen programmer. The 28-SSOP package requires careful thermal profile control during reflow soldering.
This page synthesizes distributor pricing, drop-in SSOP-package alternatives, and practical design notes not found in the standalone manufacturer datasheet.
Drop-in alternatives for PIC16C55T-XTE/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-XTE/SS (same form factor and footprint) — differing in Program Memory Size, Program Memory Type, Oscillator Type, Package, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55T-XT/SS
✅ Drop-In✓ In Stock
$2.64 / Unit
View Datasheet →PIC16C55T-HSI/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C55-HSI/SS
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →PIC16C55-LPI/SS
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC16C55T-HS/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F57-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55T-XTE/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit RISC (PIC16C5X family, Harvard) |
| CPU Family | PIC® 16C |
| Maximum Clock Frequency | 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Program Memory Size | 768 Bytes (512 x 12 bits) |
| Data RAM | 24 Bytes |
| Instruction Word Width | 12 bits |
| Instruction Set Size | 33 single-word instructions |
| Supply Voltage | 3.3 V to 5.5 V |
| I/O Pins | 20 general-purpose |
| Package | 28-pin SSOP (5.30 mm body width) |
| Mounting Type | Surface Mount |
| Peripherals | Power-on Reset (POR), Watchdog Timer (WDT), 8-bit Timer/Counter |
PIC16C55T-XTE/SS Pin Configuration
| Pin 1 | RA2 — GPIO Port A bit 2 |
| Pin 2 | RA3 — GPIO Port A bit 3 |
| Pin 3 | T0CKI — Timer 0 clock input |
| Pin 4 | MCLR — Master Clear (reset) input |
| Pin 5 | VSS — Ground |
| Pin 6 | RB0 — GPIO Port B bit 0 |
| Pin 7 | RB1 — GPIO Port B bit 1 |
| Pin 8 | RB2 — GPIO Port B bit 2 |
| Pin 9 | RB3 — GPIO Port B bit 3 |
| Pin 10 | RB4 — GPIO Port B bit 4 |
| Pin 11 | RB5 — GPIO Port B bit 5 |
| Pin 12 | RB6 — GPIO Port B bit 6 |
| Pin 13 | RB7 — GPIO Port B bit 7 |
| Pin 14 | VSS — Ground |
| Pin 15 | OSC2 — Oscillator output (crystal/resonator) |
| Pin 16 | OSC1 — Oscillator input (crystal/resonator) |
| Pin 17 | VDD — Positive supply (3.3V to 5.5V) |
| Pin 18 | RC0 — GPIO Port C bit 0 |
| Pin 19 | RC1 — GPIO Port C bit 1 |
| Pin 20 | RC2 — GPIO Port C bit 2 |
| Pin 21 | RC3 — GPIO Port C bit 3 |
| Pin 22 | RC4 — GPIO Port C bit 4 |
| Pin 23 | RC5 — GPIO Port C bit 5 |
| Pin 24 | RC6 — GPIO Port C bit 6 |
| Pin 25 | RC7 — GPIO Port C bit 7 |
| Pin 26 | RA0 — GPIO Port A bit 0 |
| Pin 27 | RA1 — GPIO Port A bit 1 |
| Pin 28 | VDD — Positive supply (3.3V to 5.5V) |
Typical Applications
PIC16C55T-XTE/SS is suitable for 7 applications: Consumer Appliance Control, Simple Sensor Interface Hub, LED Display Drivers, Low-End Remote Controls, Industrial Timers and Counters, Educational and Hobby Projects, Automotive Interior Accessories.
Consumer Appliance Control
The PIC16C55T-XTE/SS suits simple consumer appliance control boards where deterministic firmware execution and minimal BOM cost outweigh processing throughput. Its 4 MHz clock, 20 GPIO pins, and integrated POR plus Watchdog Timer handle button matrix scanning, LED indicator driving, and relay control without external supervisory components. The 768-byte OTP memory stores finalized firmware for high-volume appliance production. Compared with newer ARM Cortex-M0 parts, this PIC delivers lower unit cost and a smaller code footprint thanks to its 12-bit instruction word, while accepting slower response times due to the 250 ns instruction cycle.
Recommended
Simple Sensor Interface Hub
The PIC16C55T-XTE/SS functions as a low-cost sensor-polling hub in industrial and building-automation sensor nodes. Its 20 GPIO pins read multiple switch-contact or analog-front-end outputs while the 8-bit timer/counter generates precise sample intervals. The Watchdog Timer recovers from firmware lockups, critical in unattended sensor installations. With 24 bytes of RAM the part handles rolling averages and threshold checks but not heavy DSP, so designers should keep filter coefficients short. Operating from 3.3V to 5.5V allows direct connection to common 5V sensor rails without level shifting.
Recommended
LED Display Drivers
The PIC16C55T-XTE/SS drives multiplexed 7-segment or dot-matrix LED displays in price-sensitive signage and indicator panels. The 20 GPIO pins connect directly to segment/row drivers, and the 4 MHz clock refreshes displays at rates above the flicker fusion threshold with minimal CPU loading. The 768-byte OTP memory holds lookup tables for character decoding and animation sequences. The 28-SSOP package keeps the MCU footprint compact enough for handheld signage and small appliance front panels. Designers should use current-limiting resistors and consider Charlieplexing if more than 20 LEDs must be driven without external drivers.
Recommended
Low-End Remote Controls
The PIC16C55T-XTE/SS fits infrared or RF remote-control transmitters for TVs, fans, and audio equipment where button count, low cost, and long battery life matter most. The integrated POR and Watchdog Timer keep the remote responsive after battery swaps, and the CMOS design minimizes sleep current. With 20 GPIO pins, the part easily accommodates 4x4 button matrices plus status LEDs. The 4 MHz clock generates standard 38 kHz carrier frequencies for IR transmission with simple timer-based modulation. Designers should verify IR protocol timing against the 250 ns instruction cycle to confirm pulse-width accuracy.
Recommended
Industrial Timers and Counters
The PIC16C55T-XTE/SS implements standalone industrial timers, event counters, and process-interval controllers on factory floors. The 8-bit timer/counter with external T0CKI input counts pulses from flow meters, conveyor encoders, or line-frequency sources, while the Watchdog Timer guards against ESD-induced firmware upsets common in industrial environments. The 3.3V to 5.5V supply range interfaces directly to 5V PLC-style logic. The OTP memory prevents unauthorized firmware modification. For applications requiring more RAM or ROM, the PIC16C558 family in the same 28-SSOP package offers 128 bytes RAM and 2K program memory.
Recommended
Educational and Hobby Projects
The PIC16C55T-XTE/SS serves as a learning platform for students and hobbyists exploring 8-bit RISC microcontrollers. The PIC16C5X architecture has a small, well-documented 33-instruction set that beginners can master in days. The 4 MHz clock, 24-byte RAM, and 20 GPIO pins provide enough complexity to teach timers, interrupts, and I/O without overwhelming newcomers. MPLAB development tools support this device with simulators and programmers. Hobbyists should note that OTP memory cannot be reprogrammed, so dev work should use a windowed or flash-based sibling like the PIC16F57-I/SS during code bring-up before committing firmware to the PIC16C55T-XTE/SS for production.
Recommended
Automotive Interior Accessories
The PIC16C55T-XTE/SS operates in non-safety automotive interior accessories such as ambient lighting controllers, simple HVAC panel interfaces, and auxiliary switch inputs. Its 20 GPIO pins scan switch matrices and drive LED rings, while the Watchdog Timer recovers from transient electrical noise. The 28-SSOP package handles automotive underhood temperature extremes only if part variants with appropriate temperature grades (e.g., industrial -40C to +85C) are specified. For safety-critical body electronics, designers should migrate to AEC-Q100-qualified PIC16F or dsPIC families that share the 28-SSOP footprint and add automotive-grade qualification.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55T-XTE/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55T-XT/SS | PIC16C55T-HSI/SS | PIC16C55-HSI/SS | PIC16C55-LPI/SS | PIC16F57-I/SS |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | 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 | 28-SSOP - same |
| Max Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| Program Memory Type | OTP (768 Bytes) | OTP (768 Bytes) | OTP (768 Bytes) | OTP (768 Bytes) | OTP (768 Bytes) | Flash (2 KB) |
| Data RAM | 24 Bytes | 24 Bytes | 24 Bytes | 24 Bytes | 24 Bytes | 72 Bytes |
| Oscillator Type | Crystal/Resonator (XT) | Crystal/Resonator (XT) | High-Speed Internal | High-Speed Internal | Low-Power Crystal | Configurable (HS/XT/LP/RC) |
| In-Circuit Debug | No (OTP) | No (OTP) | No (OTP) | No (OTP) | No (OTP) | Yes (ICD) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Active |
| Instruction Set | 33 instructions (12-bit) | 33 instructions (12-bit) | 33 instructions (12-bit) | 33 instructions (12-bit) | 33 instructions (12-bit) | 35 instructions (14-bit) |
Key Differentiators
- Internal-oscillator variant avoids external crystal (vs PIC16C55T-HSI/SS)
- Flash memory and ICD support for development (vs PIC16F57-I/SS)
- Active lifecycle vs obsolete status (vs PIC16F57-I/SS)
Design Notes
The PIC16C55T-XTE/SS uses One-Time Programmable (OTP) memory that cannot be erased after programming. During development, use a flash-based sibling like PIC16F57-I/SS in the same 28-SSOP footprint to iterate firmware, then commit the finalized code to the OTP part for production. Plan for a programming adapter or socket during board bring-up, since the SSOP package is difficult to program in-circuit without dedicated test points.
Place a 100 nF decoupling capacitor within 5 mm of the VDD pin (pin 17 and pin 28 both carry VDD on the SSOP-28) and a 10 uF bulk capacitor at the board supply entry. The MCLR pin (pin 4) requires a 10 kohm pull-up to VDD for normal operation; add a 100 nF cap on MCLR to VDD for ESD protection. Keep the OSC1/OSC2 traces short and symmetric, with the crystal or resonator placed within 10 mm of pins 15-16 to minimize EMI and startup issues.
The PIC16C55T-XTE/SS draws roughly 2 mA active at 4 MHz and 5V, with much lower sleep current depending on configuration. For battery-powered designs, use the SLEEP instruction and rely on Watchdog Timer wakeup to achieve average currents below 100 uA. Ensure supply voltage stays within 3.3V to 5.5V; operation outside this range can trigger erratic resets or POR misfires. Estimated: I/O sourcing 20 mA per pin max with total port limits of 100 mA - check the absolute maximum ratings in the datasheet before driving heavy loads directly.
The 28-SSOP package has a 0.65 mm pin pitch, requiring fine-pitch PCB manufacturing (0.15 mm trace/space capability minimum). Reserve at least 1 mm of clearance around the SSOP land pattern for inspection and rework. If using both VDD pins (17 and 28) and both VSS pins (5 and 14), route power as a star pattern from a single decoupling point to avoid ground bounce. For high-noise environments, place a ferrite bead in series with the supply trace feeding the MCU.
Compliance Information
PIC16C5X family predates widespread RoHS adoption; RoHS and lead-free status not confirmed in current distributor listings. Not AEC-Q100 qualified; for automotive applications, evaluate AEC-Q100-qualified PIC16F or dsPIC families in the same 28-SSOP footprint.
