PIC16C55-10/SO - 8-bit OTP MCU, 768B, 20 I/O, 10MHz SOIC-28 | Microchip
MPN: PIC16C55-10/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.9 | $3.90 |
| 10 | $3.51 | $35.10 |
| 100 | $3.12 | $312.00 |
| 500 | $2.8 | $1,400.00 |
| 1,000 | $2.49 | $2,490.00 |
PIC16C55-10/SO Overview
What is a PIC16C5x baseline MCU? The PIC16C5x family is Microchip's original baseline 8-bit microcontroller line, sitting below the mid-range PIC16 and enhanced PIC17/PIC18 in capability. Baseline MCUs use a 12-bit instruction word, a two-level hardware stack, and seven or eight special function registers. They are intended for low-cost, deterministic bit-IO and timing applications where advanced peripherals such as ADC, UART, or PWM are not required. PIC16C5x parts fall under the broader taxonomy: microcontroller -> 8-bit MCU -> embedded controller -> semiconductor.
Key features of the PIC16C55-10/SO include a real-time clock/counter (TMR0) with an 8-bit prescaler, direct/indirect/relative addressing modes for both operands, a two-level deep hardware call stack, and a watchdog timer (WDT) with its own on-chip RC oscillator for recovery without external intervention. The device supports internal or external oscillator modes and offers low-power SLEEP mode with wake-up on pin change or watchdog timeout.
Architecturally, the PIC16C55-10 uses a Harvard architecture with separate program and data buses, allowing instruction fetch and operand access in a single clock cycle. The OTP program memory is written using a production programmer such as the MPLAB PM3; once programmed, the code is non-volatile but not erasable, making the PIC16C55 family well suited to mature production designs where code stability has been validated. The 20 I/O pins are bidirectional and individually configurable for input or output.
Typical applications for the PIC16C55-10/SO include small appliance controllers, HVAC damper and fan controls, LED chasers and decorative lighting sequencers, simple sensor readers with digital outputs, automotive body-electronics nodes, and any cost-sensitive embedded design that needs deterministic IO without an RTOS. The wide-body SOIC-28 footprint simplifies hand-soldering and rework on prototype boards compared to smaller QFN packages.
A key design consideration is OTP-only program memory: firmware must be 100% verified before programming. Consider migrating to the flash-based PIC16F57 (pin-compatible in most pad-outs) if your design still needs in-field firmware updates. Use MPLAB XC8 with the baseline compiler setting for code generation.
This page synthesizes real distributor pricing, parametric cross-references to PIC16C5x family pin-compatible variants, and practical design notes not consolidated on a single manufacturer page.
Drop-in alternatives for PIC16C55-10/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 PIC16C55-10/SO (same form factor and footprint) — differing in Package, Program Memory Size, Timers, Program Memory Type, Core.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-10I/SO
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC16C55-20/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56-10/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C54-10/SO
✅ Drop-In✓ In Stock
$1.02 / Unit
View Datasheet →PIC16F57-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55-10/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C5x baseline 8-bit RISC |
| Instruction Set | 12-bit wide, 33 instructions, single-cycle (200 ns @ 10 MHz) |
| Program Memory Type | OTP (One-Time-Programmable) EPROM |
| Program Memory Size | 768 bytes (512 x 12 words) |
| RAM Size | 24 bytes |
| I/O Pins | 20 |
| Maximum Clock Frequency | 10 MHz |
| Supply Voltage (VDD) | 4.5 V to 5.5 V |
| Timers | TMR0 (8-bit) with 8-bit prescaler |
| Watchdog Timer (WDT) | Yes, with dedicated on-chip RC oscillator |
| Hardware Stack | 2-level deep |
| Addressing Modes | Direct, indirect, relative |
| Oscillator Modes | External RC, external crystal/ceramic, internal (some variants) |
| Package | 28-pin SOIC (SO), 0.295" / 7.50 mm wide body |
| Operating Temperature Range | 0C to +70C (commercial, per -10/SO speed/temp grade) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited floor life, hermetic SOIC package) |
| Programming Method | MPLAB PM3 or compatible ICSP programmer |
PIC16C55-10/SO Pin Configuration
| Pin 1 | /MCLR/VPP — Master Clear (active-low reset) / Programming voltage input |
| Pin 2 | RA0 — PORTA bit 0 (bidirectional I/O) |
| Pin 3 | RA1 — PORTA bit 1 (bidirectional I/O) |
| Pin 4 | RA2 — PORTA bit 2 (bidirectional I/O) |
| Pin 5 | RA3 — PORTA bit 3 (bidirectional I/O) |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RB0/INT — PORTB bit 0 / External interrupt input |
| Pin 8 | RB1 — PORTB bit 1 (bidirectional I/O) |
| Pin 9 | RB2 — PORTB bit 2 (bidirectional I/O) |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage (+5V nominal) |
| Pin 12 | RB3 — PORTB bit 3 (bidirectional I/O) |
| Pin 13 | RB4 — PORTB bit 4 (bidirectional I/O) |
| Pin 14 | RB5 — PORTB bit 5 (bidirectional I/O) |
| Pin 15 | RB6 — PORTB bit 6 (bidirectional I/O) |
| Pin 16 | RB7 — PORTB bit 7 (bidirectional I/O) |
| Pin 17 | RC0 — PORTC bit 0 (bidirectional I/O) |
| Pin 18 | OSC2/CLKOUT — Oscillator crystal output / CLKOUT |
| Pin 19 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 20 | RC1 — PORTC bit 1 (bidirectional I/O) |
| Pin 21 | RC2 — PORTC bit 2 (bidirectional I/O) |
| Pin 22 | RC3 — PORTC bit 3 (bidirectional I/O) |
| Pin 23 | RC4 — PORTC bit 4 (bidirectional I/O) |
| Pin 24 | RC5 — PORTC bit 5 (bidirectional I/O) |
| Pin 25 | RC6 — PORTC bit 6 (bidirectional I/O) |
| Pin 26 | RC7 — PORTC bit 7 (bidirectional I/O) |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C55-10/SO is suitable for 7 applications: Small Appliance Controllers, HVAC Damper and Fan Control, LED Chaser and Decorative Lighting Sequencers, Automotive Body Electronics Nodes, Simple Sensor Readout Modules, Toy and Consumer Electronics Controllers, Industrial Timer and Sequencer Modules.
Small Appliance Controllers
The PIC16C55-10/SO fits small appliance controllers such as toaster ovens, coffee makers, and countertop blenders where deterministic bit-IO and simple state machines replace mechanical timers. Its 20 I/O pins easily drive 7-segment displays, relay coils, and keypad matrices, while 768 bytes of OTP memory is sufficient for timing curves, mode logic, and user-interface debouncing. The 10 MHz instruction cycle provides 200 ns response time, adequate for zero-crossing triac triggering and motor PWM at appliance-grade frequencies. The wide-body SOIC-28 simplifies hand-soldering during prototype bring-up on through-hole adapter boards. For designs that need in-field firmware updates after launch, plan a migration path to the PIC16F57-I/SO which shares the SOIC-28 footprint.
Recommended
HVAC Damper and Fan Control
In HVAC damper actuators and multi-speed fan controllers, the PIC16C55-10/SO provides the deterministic timing and bidirectional I/O count needed to drive triac switches and read temperature sensors through the TMR0-triggered ADC-free conversion techniques common in baseline PIC designs. The 24-byte RAM is sufficient to hold set-point, hysteresis band, and current-mode flags. Operating from a regulated 5V rail, the device tolerates the electrical noise of motor switching with its watchdog timer providing recovery from firmware lockups. Commercial temperature grade (0C to +70C) fits indoor equipment; specify PIC16C55-10I/SO for outdoor condensing-unit controls.
Recommended
LED Chaser and Decorative Lighting Sequencers
LED chaser and decorative lighting sequencers rely on precise PWM-free bit-banging at fixed update rates, an ideal workload for the PIC16C55-10/SO. With 20 I/O pins, the controller can directly drive up to 20 LED strings through MOSFET drivers without external multiplexers, or scan an 8x8 LED matrix with row-column decode. The 10 MHz instruction rate supports smooth 8-bit PWM at refresh rates above 100 Hz for flicker-free dimming. OTP memory suits decorative designs where the lighting pattern is fixed once validated. Use the SLEEP mode for battery-powered holiday decorations to reduce quiescent draw between animation frames.
Recommended
Automotive Body Electronics Nodes
Automotive body-electronics nodes such as door-lock controllers, mirror-adjust drivers, and seat-position memories use the PIC16C55-10/SO for its deterministic interrupt-free IO and robust 5V supply tolerance. The 20 I/O pins handle switch scanning, relay drive, and LIN-slave emulation via UART-bit-banging. While this OTP-grade part is commercial-temperature, automotive designs typically use the PIC16C55-10I/SO (industrial) or PIC16C55A automotive-grade variant for the -40C to +125C underhood range. The SOIC-28 wide-body withstands vibration better than QFN equivalents in module-mounted applications.
Recommended
Simple Sensor Readout Modules
The PIC16C55-10/SO is well suited to simple sensor readout modules that digitize one or two analog channels using TMR0-based RC-charge timing and present the result on a digital display or UART-bit-bang output. The 768-byte program memory holds calibration coefficients and lookup tables for linearization, while 24 bytes of RAM supports running-average filtering. With 20 I/O pins, the device can directly interface to 4-digit 7-segment displays, button keypads, and UART outputs without external logic. Specify PIC16C55-10I/SO for industrial sensor installations operating from -40C to +85C.
Recommended
Toy and Consumer Electronics Controllers
Cost-sensitive toy and consumer electronics such as educational robots, electronic learning aids, and animated plush toys benefit from the PIC16C55-10/SO's low unit price and straightforward 5V operation. Its 20 I/O pins drive servo motors, sound chips, and LED matrices; its 768-byte OTP holds pre-programmed motion sequences and sound-trigger logic. The wide-body SOIC-28 package is easy for contract assemblers to handle on high-mix production lines. For toy designs that need firmware tweaks between seasonal product runs, evaluate the PIC16F57-I/SO flash-based variant as an alternative.
Recommended
Industrial Timer and Sequencer Modules
Industrial timer and sequencer modules in factory automation use the PIC16C55-10/SO to provide deterministic event timing with relay outputs and digital control inputs. The 10 MHz clock provides 100 ns instruction granularity, sufficient for cascaded timer chains with millisecond resolution across multiple outputs. The hardware watchdog timer with dedicated RC oscillator provides recovery from electrical disturbances common in industrial environments without external components. Operating from 5V, the part integrates easily with 24V-to-5V regulated control boards. Specify the PIC16C55-10I/SO for installations spanning -40C to +85C ambient.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55-10/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-10I/SO | PIC16C55-20/SO | PIC16C56-10/SO | PIC16C54-10/SO | PIC16F57-I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SOIC-28 (0.295", 7.50 mm) | SOIC-28 - same | SOIC-28 - same | SOIC-28 - same | SOIC-28 - same | SOIC-28 - same |
| Program Memory | 768 bytes OTP | 768 bytes OTP | 768 bytes OTP | 1536 bytes OTP (+100%) | 512 bytes OTP (-33%) | 3 KB Flash (reprogrammable) |
| Maximum Clock Speed | 10 MHz | 10 MHz | 20 MHz (+100%) | 10 MHz | 10 MHz | 20 MHz |
| RAM Size | 24 bytes | 24 bytes | 24 bytes | 24 bytes | 24 bytes | 72 bytes (+200%) |
| I/O Pins | 20 | 20 | 20 | 20 | 12 (-40%) | 20 |
| Operating Temperature | 0C to +70C (commercial) | -40C to +85C (industrial) | 0C to +70C (commercial) | 0C to +70C (commercial) | 0C to +70C (commercial) | -40C to +85C (industrial) |
| Program Memory Type | OTP EPROM (one-time programmable) | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | Flash (in-circuit reprogrammable) |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.0 V to 5.5 V (wider range) |
Key Differentiators
- Larger program memory in same SOIC-28 footprint (vs PIC16C54-10/SO)
- Industrial temperature grade drop-in option (vs PIC16C55-10I/SO)
- Flash reprogrammability migration path (vs PIC16F57-I/SO)
- Higher clock headroom in same package (vs PIC16C55-20/SO)
Design Notes
The PIC16C55-10/SO operates from a single 4.5V to 5.5V supply and draws approximately 2-5 mA active current at 10 MHz plus I/O sinking current. Provide a 100 nF decoupling capacitor within 5 mm of the VDD pin (pin 11) and a bulk 10 uF tantalum or aluminum capacitor at the board power entry. The /MCLR pin (pin 1) requires a 10 kohm pull-up to VDD for normal operation; if not used, leave it tied to VDD directly. Add a series resistor (100-470 ohm) on /MCLR if the pin will also serve as ICSP programming entry to limit inrush.
Place the external crystal or ceramic resonator within 10 mm of pins 18 (OSC2) and 19 (OSC1), with short traces and a ground plane cutout around the oscillator cell to minimize coupling to adjacent signal traces. Avoid routing the OSC traces parallel to I/O lines or under high-current traces. The /MCLR trace should be kept short and away from switching signals. Place a ground ring around the crystal can and tie both ends to VSS with short stubs to reduce EMI radiation.
OTP program memory cannot be erased: validate firmware 100% on a windowed CERDIP (JW) part before committing to SOIC production. The PIC16C55 lacks an internal ADC, so analog inputs require external RC-charge timing or dedicated ADC ICs. The 2-level hardware stack limits call depth - subroutines cannot nest deeper than 2 levels, and ISRs cannot safely call other subroutines. Watchdog timer must be explicitly disabled in configuration bits if not used, otherwise it will reset the part unexpectedly. Sleep wakeup from WDT requires careful main-loop state management.
Estimated: at 10 MHz active operation with all 20 I/O pins sourcing/sinking 10 mA each, total dissipation is approximately 200 mW from internal logic plus 200 mW worst-case I/O drive, totalling 400 mW. The 28-pin SOIC wide-body has a theta_JA of approximately 85 C/W, yielding a junction temperature rise of 34 C above 25 C ambient (59 C junction) - well within the 0C to +70C commercial range. For industrial-temperature PIC16C55-10I/SO parts, derate by 20% at 85 C ambient.
Compliance Information
RoHS and REACH compliance status not explicitly confirmed in the provided distributor data; PIC16C5x family SOIC parts are typically lead-free but full compliance certificates should be requested from Microchip. AEC-Q100 not qualified - use PIC16C55A automotive-grade variant for automotive applications.
