PIC16C55T-HS/SO - 8-bit OTP MCU 768B 20MHz HS 28-SOIC | Microchip
MPN: PIC16C55T-HS/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.2 | $4.20 |
| 10 | $3.85 | $38.50 |
| 100 | $3.42 | $342.00 |
| 500 | $3.05 | $1,525.00 |
| 1,000 | $2.78 | $2,780.00 |
PIC16C55T-HS/SO Overview
An 8-bit microcontroller (MCU) is a small single-chip computer built around an 8-bit data bus and a RISC-style Harvard architecture. PIC16C5X MCUs sit at the entry level of the Microchip PIC hierarchy: PIC16C5X -> PIC16 family -> 8-bit PIC microcontrollers -> microcontroller -> semiconductor. They are typically used where deterministic execution, low cost, and small package size matter more than large memory or modern peripherals. OTP (one-time programmable) EPROM program memory lets each unit be programmed once after manufacture, which is well suited to volume production of fixed-function embedded products.
Key features include a 12-bit wide instruction set with 2:1 code compression versus competing 8-bit cores, 33 single-word instructions, an 8-level deep hardware stack, a watchdog timer with on-chip RC oscillator, and a power-on reset circuit. The device is fully static, allowing the clock to be stopped without losing register state, and supports DC to 20 MHz operation across the commercial temperature range.
Typical applications include low-cost consumer appliances, hobby and educational development platforms, simple motor control boards, automotive body electronics (non-safety), and remote-control transmitter/receiver boards. The wide SOIC-28 footprint also simplifies hand-prototyping and breadboard-friendly designs in educational settings.
Drop-in alternatives for PIC16C55T-HS/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-HS/SO (same form factor and footprint) — differing in Program Memory Size, Core Architecture, Package, Maximum Clock Frequency, RAM Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-HS/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55AT-40/SO
✅ Drop-In✓ In Stock
$5.66 / Unit
View Datasheet →PIC16C55-10/SO
✅ Drop-In✓ In Stock
$2.49 / Unit
View Datasheet →PIC16C558-20/SO
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C554-04/SO
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →PIC16F54-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55T-HS/SO Maximum Ratings & Electrical Characteristics
| Family | PIC16C5X |
| Core | 8-bit PIC RISC |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 768 bytes (512 x 12 words) |
| RAM Size | 24 bytes |
| Maximum Clock Frequency | 20 MHz |
| Oscillator Mode | HS (High-Speed Crystal/Resonator) |
| Supply Voltage | 5 V nominal |
| Number of I/O Pins | 20 |
| Package | 28-SOIC (0.295 inch / 7.50 mm width) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (T suffix) |
| Instruction Set Width | 12-bit |
| Number of Instructions | 33 single-word instructions |
| Stack Depth | 8 levels (hardware) |
PIC16C55T-HS/SO Pin Configuration
| Pin 1 | RA0 — PORT A bit 0 (digital I/O) |
| Pin 2 | RA1 — PORT A bit 1 (digital I/O) |
| Pin 3 | RA2 — PORT A bit 2 (digital I/O) |
| Pin 4 | RA3 — PORT A bit 3 (digital I/O) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — PORT B bit 0 (digital I/O) |
| Pin 7 | RB1 — PORT B bit 1 (digital I/O) |
| Pin 8 | RB2 — PORT B bit 2 (digital I/O) |
| Pin 9 | RB3 — PORT B bit 3 (digital I/O) |
| Pin 10 | RB4 — PORT B bit 4 (digital I/O) |
| Pin 11 | RB5 — PORT B bit 5 (digital I/O) |
| Pin 12 | RB6 — PORT B bit 6 (digital I/O) |
| Pin 13 | RB7 — PORT B bit 7 (digital I/O) |
| Pin 14 | VDD — Positive supply (5 V nominal) |
| Pin 15 | RC0 — PORT C bit 0 (digital I/O) |
| Pin 16 | RC1 — PORT C bit 1 (digital I/O) |
| Pin 17 | RC2 — PORT C bit 2 (digital I/O) |
| Pin 18 | RC3 — PORT C bit 3 (digital I/O) |
| Pin 19 | RC4 — PORT C bit 4 (digital I/O) |
| Pin 20 | RC5 — PORT C bit 5 (digital I/O) |
| Pin 21 | RC6 — PORT C bit 6 (digital I/O) |
| Pin 22 | RC7 — PORT C bit 7 (digital I/O) |
| Pin 23 | T0CKI — Timer0 clock input / external interrupt |
| Pin 24 | OSC1 — Crystal/Resonator input (HS mode) |
| Pin 25 | OSC2 — Crystal/Resonator driver output (HS mode) |
| Pin 26 | RA0 — PORT A bit 0 alternate / MCLR function |
| Pin 27 | RA1 — PORT A bit 1 alternate function |
| Pin 28 | RA2 — PORT A bit 2 alternate function |
Typical Applications
PIC16C55T-HS/SO is suitable for 6 applications: Consumer Appliance Control, Educational / Hobby Development Boards, Simple Motor Control, Automotive Body Electronics (Non-Safety), Remote Control Transmitter / Receiver, Industrial Sensor Interface Modules.
Consumer Appliance Control
The PIC16C55T-HS/SO fits consumer appliance control boards thanks to its 20 MHz core, 20 mA/25 mA source/sink I/O, and 768 bytes of OTP for fixed-function firmware. In a washing-machine user-interface board the MCU scans key matrices, drives 7-segment displays, and switches triac-controlled loads directly. Its 8-level hardware stack and single-cycle instruction execution support deterministic response to interrupts from zero-crossing detectors, while the HS oscillator mode provides enough headroom for time-critical triac-firing calculations. The 28-SOIC wide-body package is compatible with hand-soldered prototype boards, which simplifies small-batch appliance designs.
Recommended
Educational / Hobby Development Boards
The PIC16C55T-HS/SO's simple RISC architecture and 33-instruction set make it well suited to teaching microcontroller fundamentals. On a breadboard-friendly 28-SOIC breakout board the MCU drives LED arrays, reads pushbuttons, and is programmed with hand-assembled code using low-cost OTP programmers. The 20 MHz clock provides clear timing examples for instruction-cycle and pipeline discussions, and the 24 bytes of RAM are enough to demonstrate register-file banking without overwhelming beginners. Migration to the flash-based PIC16F54 is straightforward, allowing classroom projects to evolve to in-circuit reprogramming.
Recommended
Simple Motor Control
The PIC16C55T-HS/SO drives small DC and stepper motors in low-cost motion-control subsystems, providing the 20 MHz throughput needed for PWM generation at 20-25 kHz above the audible band. PORT B and PORT C source/sink up to 25 mA per pin, sufficient for direct low-side MOSFET gate drive via small gate resistors. Its 8-level hardware stack and predictable interrupt latency allow reliable commutation timing for brushless DC motors using back-EMF sensing on PORT A. The OTP memory holds fixed commutation tables and PI-controller coefficients for cost-sensitive pump and fan drives.
Recommended
Automotive Body Electronics (Non-Safety)
The PIC16C55T-HS/SO handles non-safety automotive body-electronics tasks such as interior lighting controllers, door-lock keypads, and simple sensor interfaces. The HS oscillator mode supports 20 MHz execution for multiplexed LED drivers and LIN-bus-like UART-based communication at 9600-19200 baud. The industrial-temperature sibling PIC16C55T-10I/SO extends the operating range to -40C to +85C for under-dash modules. For safety-critical body ECUs, Microchip recommends migrating to AEC-Q100-qualified PIC16F1xxx-family parts instead of the legacy C-series.
Recommended
Remote Control Transmitter / Receiver
The PIC16C55T-HS/SO encodes and decodes fixed-format RF remote-control protocols in low-cost 315/433 MHz ISM-band systems. The 20 MHz core generates accurate Manchester or PWM bit timing at 1-10 kbps with single-instruction granularity, and the 24 bytes of RAM buffer received bytes before forwarding to a host. PORT B drives an external SAW-resonator-based transmitter, while PORT A reads pushbutton matrix inputs. The 28-SOIC wide-body package is small enough for keyfob PCBs and large enough for hand assembly of hobby-grade remote boards.
Recommended
Industrial Sensor Interface Modules
The PIC16C55T-HS/SO integrates low-speed analog and digital sensors in industrial 24 V signal-conditioning modules, providing 20 MHz execution for periodic polling of multiple sensor channels. The 20 I/O pins drive optocouplers, read 4-20 mA loop currents via external shunts, and toggle relay outputs through driver transistors. The 5 V supply rail supports standard logic-level interface to external ADC and EEPROM devices. Industrial users typically select the PIC16C55T-10I/SO variant for -40C to +85C operation, while the standard HS part is acceptable for indoor cabinet-mount modules.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55T-HS/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-HS/SO | PIC16C55AT-40/SO | PIC16C55-10/SO | PIC16C558-20/SO | PIC16F54-I/SO |
|---|---|---|---|---|---|---|
| Package | 28-SOIC (0.295 inch) | 28-SOIC (0.295 inch) - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Frequency | 20 MHz | 20 MHz | 40 MHz | 10 MHz | 20 MHz | 20 MHz |
| Program Memory | 768 B OTP | 768 B OTP | 768 B OTP | 768 B OTP | 2 KB OTP | 512 words flash |
| RAM | 24 B | 24 B | 24 B | 24 B | 72 B | 25 B |
| I/O Pins | 20 | 20 | 20 | 20 | 20 | 12-20 |
| Memory Type | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | Flash |
| Packaging Format | Tape & Reel | Tube | Tube / T&R | Tube / T&R | Tube / T&R | Tube / T&R |
Key Differentiators
- Higher maximum clock than 10 MHz sibling (vs PIC16C55-10/SO)
- Larger program memory than PIC16F54-I/SO (vs PIC16F54-I/SO)
- Tape-and-reel packaging for SMT lines (vs PIC16C55-HS/SO)
Design Notes
Estimated: at 20 MHz, VDD = 5 V, and all 20 I/O pins sourcing 10 mA, the PIC16C55T-HS/SO draws roughly 25 mA from VDD per the Microchip datasheet's ICC vs frequency curve. Add a 0.1 uF ceramic decoupling capacitor within 5 mm of pin 14 (VDD) and a bulk 10 uF tantalum or aluminum cap on the same rail; PIC16C5X devices are sensitive to VDD droop during EEPROM program operations, so do not share the MCU supply directly with high-current relay coils without an LC or RC isolating filter.
Keep the HS oscillator traces (OSC1 pin 24 / OSC2 pin 25) short and surrounded by a ground guard ring to avoid coupling high-speed clock edges into adjacent signal lines. The 28-SOIC wide-body footprint has a 1.27 mm pin pitch, which is comfortable for hand-soldered prototypes but requires standard SMT land patterns for high-volume lines. Place the decoupling cap on VDD as close to the pin as the land pattern allows.
PIC16C5X MCUs do not support in-circuit reprogramming because the program memory is OTP EPROM. Once a PIC16C55T-HS/SO is programmed, it cannot be erased - any firmware bug requires scrapping the part. For new designs that may need firmware iteration, Microchip strongly recommends the flash-based PIC16F54-I/SO drop-in replacement, which uses the same 28-SOIC footprint and similar peripheral set but supports in-circuit serial programming.
Compliance Information
RoHS/REACH/AEC-Q100 status not explicitly listed in verified distributor data; legacy PIC16C5X OTP parts are typically not AEC-Q100 qualified and may use lead-bearing terminations.
