PIC16C55T-XT/SS - 8-bit 4MHz OTP MCU 768B | 28-SSOP
MPN: PIC16C55T-XT/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.32 | $4.32 |
| 10 | $3.89 | $38.90 |
| 100 | $3.41 | $341.00 |
| 500 | $2.97 | $1,485.00 |
| 1,000 | $2.64 | $2,640.00 |
PIC16C55T-XT/SS Overview
An 8-bit OTP microcontroller is a single-chip microcomputer containing a CPU, program memory, data RAM, and peripheral I/O on one die. The OTP (One-Time Programmable) memory uses fuse/antifuse or EPROM cells that can be written once with a device programmer but cannot be electrically erased; this gives PIC16C5X parts a low-cost, low-power profile suited to high-volume production where firmware is finalized. The PIC16C5X family implements a RISC architecture with only 33 single-word/single-cycle instructions, allowing most instructions to execute in one clock cycle for deterministic throughput at low MHz.
Key specifications include 4 MHz maximum operating frequency, 768 bytes (512 x 12) OTP program memory, 24 bytes of RAM, 20 I/O pins, and a 3.0V to 6.25V supply voltage range. The device uses an external XT oscillator (crystal/resonator up to 4 MHz) and operates over the commercial 0°C to 70°C temperature range. The 28-SSOP (5.30 mm width, 0.65 mm pitch) package enables high-density board layouts while remaining hand-solderable for prototype builds.
The PIC16C55 architecture employs a Harvard-style separate program/data bus, with a 12-bit-wide instruction word. Peripherals include a watchdog timer, power-on reset, and a 8-bit timer/counter with optional prescaler. The 20 I/O pins support TTL/CMOS levels, with individual pin direction control. Compared to its PIC16C54 sibling, the PIC16C55 offers larger program memory (768 B vs 512 B) for applications requiring additional lookup tables or state machines.
Typical applications include industrial control, appliance control, low-cost remote-control encoders, LED driver controllers, and consumer electronic toys. The wide 3.0V to 6.25V supply range and external XT oscillator support standard 4 MHz crystals used across the embedded market.
When designing with this part, ensure that firmware is finalized before programming because the OTP memory cannot be re-programmed in-circuit. For development and field updates, use a Flash-based PIC16F5X variant (e.g., PIC16F57) as a development substitute on the same SSOP footprint.
Drop-in alternatives for PIC16C55T-XT/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-XT/SS (same form factor and footprint) — differing in Package, Program Memory Size, Timers, Program Memory Type, Maximum Clock Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-XT/SS
✅ Drop-In✓ In Stock
$2.42 / Unit
View Datasheet →PIC16C55A-04/SS
✅ Drop-In✓ In Stock
$2.25 / Unit
View Datasheet →PIC16C55-LPI/SS
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC16C558-20/SS
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C55T-XT/SS Maximum Ratings & Electrical Characteristics
| Series | PIC16C5X |
| Core Processor | PIC |
| Core Size | 8-bit |
| Maximum Clock Speed | 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 768 B (512 x 12) |
| Data RAM Size | 24 B |
| Number of I/O Pins | 20 |
| Supply Voltage Range | 3.0 V to 6.25 V |
| Oscillator Type | External (XT crystal/resonator) |
| Operating Temperature Range | 0 °C to 70 °C (commercial) |
| Package | 28-SSOP (5.30 mm, 0.65 mm pitch) |
| Mounting Type | Surface Mount |
| Peripherals | Watchdog Timer, POR, 8-bit Timer/Counter with prescaler |
| Instruction Set | 33 single-word/single-cycle RISC instructions |
PIC16C55T-XT/SS Pin Configuration
| Pin 1 | RA0 — Port A bit 0 (bidirectional I/O) |
| Pin 2 | RA1 — Port A bit 1 (bidirectional I/O) |
| Pin 3 | RA2 — Port A bit 2 (bidirectional I/O) |
| Pin 4 | RA3 — Port A bit 3 (bidirectional I/O) |
| Pin 5 | VDD — Positive supply voltage |
| Pin 6 | VSS — Ground reference |
| Pin 7 | RB0 — Port B bit 0 (bidirectional I/O) |
| Pin 8 | RB1 — Port B bit 1 (bidirectional I/O) |
| Pin 9 | RB2 — Port B bit 2 (bidirectional I/O) |
| Pin 10 | RB3 — Port B bit 3 (bidirectional I/O) |
| Pin 11 | RB4 — Port B bit 4 (bidirectional I/O) |
| Pin 12 | RB5 — Port B bit 5 (bidirectional I/O) |
| Pin 13 | RB6 — Port B bit 6 (bidirectional I/O) |
| Pin 14 | RB7 — Port B bit 7 (bidirectional I/O) |
| Pin 15 | RC0 — Port C bit 0 (bidirectional I/O) |
| Pin 16 | RC1 — Port C bit 1 (bidirectional I/O) |
| Pin 17 | RC2 — Port C bit 2 (bidirectional I/O) |
| Pin 18 | RC3 — Port C bit 3 (bidirectional I/O) |
| Pin 19 | RC4 — Port C bit 4 (bidirectional I/O) |
| Pin 20 | RC5 — Port C bit 5 (bidirectional I/O) |
| Pin 21 | RC6 — Port C bit 6 (bidirectional I/O) |
| Pin 22 | RC7 — Port C bit 7 (bidirectional I/O) |
| Pin 23 | RD0 — Port D bit 0 (bidirectional I/O) |
| Pin 24 | RD1 — Port D bit 1 (bidirectional I/O) |
| Pin 25 | RD2 — Port D bit 2 (bidirectional I/O) |
| Pin 26 | RD3 — Port D bit 3 (bidirectional I/O) |
| Pin 27 | OSC1 — External crystal oscillator input (XT mode) |
| Pin 28 | OSC2 — External crystal oscillator output (XT mode) |
Typical Applications
PIC16C55T-XT/SS is suitable for 6 applications: Industrial Control Logic Replacement, Consumer Appliance Controllers, Remote Control Encoders, LED Display Drivers and Chasers, Toy and Game Electronics, Sensor Signal Pre-Processing.
Industrial Control Logic Replacement
The PIC16C55T-XT/SS fits legacy industrial control boards where the PIC16C5X footprint is already designed in, with its 4 MHz XT oscillator and 3.0-6.25 V supply matching 5V control backplanes. Its 20 GPIO pins drive relays, solenoids, and indicator LEDs through simple RC debouncing, while the watchdog timer protects against code lockup in unattended equipment. Per Microchip PIC16C5X datasheet, the 768 B OTP memory holds typical state machines for pump sequencing, conveyor control, or HVAC damper logic without requiring external storage.
Recommended
Consumer Appliance Controllers
PIC16C55T-XT/SS suits cost-sensitive consumer appliances such as coffee makers, microwave ovens, washing-machine control boards, and small kitchen appliances. The 768 B OTP memory is sufficient for menu-driven UI state machines, while 20 GPIO pins interface with keypads, 7-segment LED displays, and triac-triggered heater/timer outputs. Per Microchip PIC16C5X datasheet, the 3.0-6.25 V supply directly accepts rectified 5 V rails from appliance power supplies, eliminating the need for additional LDO regulators.
Recommended
Remote Control Encoders
PIC16C55T-XT/SS is well-suited for low-cost RF/IR remote control transmitters where the OTP memory holds fixed key-scan lookup tables. Its 4 MHz execution rate supports software-generated Manchester or PWM encoding at typical 38 kHz IR carrier rates, while the 20 GPIO directly scan 4x5 key matrices without external logic. Per Microchip PIC16C5X datasheet, the 3.0-6.25 V supply matches 3 V coin-cell or 4.5 V battery packs commonly used in remote handsets.
Recommended
LED Display Drivers and Chasers
PIC16C55T-XT/SS drives LED chaser patterns, marquee displays, and decorative lighting controllers using its 20 GPIO pins to multiplex up to 64 LEDs in a matrix arrangement via charlieplexing or row-column scanning. The 768 B OTP memory stores multiple animation patterns indexed by button inputs. Per Microchip PIC16C5X datasheet, the 4 MHz clock rate generates accurate timing for visual effects while the wide supply range accepts 3.3 V or 5 V LED driver rails.
Recommended
Toy and Game Electronics
PIC16C55T-XT/SS fits electronic toys, educational kits, and simple game consoles where cost per unit is paramount and firmware is finalized. The OTP memory prevents field tampering with game logic, while 20 GPIO directly drive speakers, vibration motors, and LED indicators. Per Microchip PIC16C5X datasheet, the 33 single-cycle instructions make timing-critical sound generation and motor control loops easy to implement without external timers or DACs.
Recommended
Sensor Signal Pre-Processing
PIC16C55T-XT/SS serves as a pre-processor for analog sensor arrays in distributed measurement systems, where the 20 GPIO read multiple digital sensors and the 4 MHz core executes linearization and threshold-detection algorithms stored in 768 B OTP memory. Per Microchip PIC16C5X datasheet, the wide 3.0-6.25 V supply accepts unregulated sensor bus voltages, while the small 28-SSOP package enables co-location with sensor elements on compact PCB modules.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55T-XT/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-XT/SS | PIC16C55A-04/SS | PIC16C55-LPI/SS | PIC16C558-20/SS |
|---|---|---|---|---|---|
| Package | 28-SSOP | 28-SSOP - same | 28-SSOP - same | 28-SSOP - same | 28-SSOP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP | OTP | OTP | OTP | OTP |
| Program Memory Size | 768 B (512 x 12) | 768 B (512 x 12) | 768 B (512 x 12) | 768 B (512 x 12) | 2 K (approx) |
| Maximum Clock Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| Number of I/O Pins | 20 | 20 | 20 | 20 | 20 |
| Supply Voltage Range | 3.0 V to 6.25 V | 3.0 V to 6.25 V | 3.0 V to 6.25 V | 2.5 V to 6.25 V | 2.5 V to 6.25 V |
| Oscillator Mode | External XT | External XT | External XT | External LP | External XT/HS |
| Operating Temperature | 0 °C to 70 °C | 0 °C to 70 °C | 0 °C to 70 °C | -40 °C to 85 °C | 0 °C to 70 °C |
Key Differentiators
- Lowest-cost OTP MCU with RISC core and 20 I/O (vs PIC16C558-20/SS)
- OTP memory lock-in for anti-tampering designs (vs PIC16F57-I/SS)
- Same 28-SSOP footprint for easy substitution (vs PIC16C55-XT/SS)
Design Notes
OTP memory cannot be electrically erased - once programmed, firmware is permanent. Engineers transitioning from PIC16F5X (Flash) parts must validate firmware on a Flash equivalent (e.g., PIC16F57-I/SS) before committing to PIC16C55T-XT/SS for production. Allocate a few prototype units for code verification before placing a volume OTP order, because field firmware updates are impossible.
Place the 4 MHz crystal and its two load capacitors (typically 15-33 pF, ceramic NPO) within 5 mm of OSC1 (pin 27) and OSC2 (pin 28). Keep crystal traces short and isolated from switching signals. Provide a guard ground ring around the oscillator area. Keep MCLR/VPP trace short to minimize in-circuit programming noise pickup; add a 100 nF decoupling capacitor on VDD (pin 5) placed within 3 mm of the pin.
PIC16C55T-XT/SS draws approximately 2.5 mA at 5 V, 4 MHz with all I/O unloaded. Estimated: with 20 GPIO each sourcing 10 mA, total supply current can reach 25 mA. Ensure the 5 V regulator provides at least 50 mA headroom and add a 10 µF bulk + 100 nF decoupling capacitor pair on VDD to handle GPIO switching transients. NRND parts should be sourced with multi-channel inventory to mitigate supply risk.
Compliance Information
RoHS and lead-free compliant per Microchip product page. Not AEC-Q100 qualified - this part targets consumer/industrial commercial applications, not automotive.
