PIC16C55T-RCI/SS - 8-Bit 4MHz OTP MCU 768B | Microchip 28-SSOP
MPN: PIC16C55T-RCI/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.2 | $7.20 |
| 10 | $6.55 | $65.50 |
| 100 | $5.9 | $590.00 |
| 500 | $5.3 | $2,650.00 |
| 1,000 | $4.85 | $4,850.00 |
PIC16C55T-RCI/SS Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, RAM, and I/O peripherals on one die. The PIC16C5X family belongs to the baseline PIC architecture using a 12-bit instruction word with a two-stage pipeline, classified under the hypernym chain: microcontroller -> embedded processor -> microprocessor -> semiconductor IC. OTP memory allows factory programming but cannot be re-written, balancing cost against in-field reprogrammability.
Key features include 20 I/O pins, an 8-bit timer/counter, watchdog timer, power-on reset, and RC oscillator support with external clock option. The device operates from 3V to 6.25V and consumes low current typical of CMOS designs. The PIC RISC architecture executes most instructions in a single cycle, providing deterministic throughput for real-time control loops. The 12-bit wide instruction word allows compact code density, and the Harvard bus keeps program and data paths separate for predictable timing.
Typical applications include industrial automation controllers, consumer appliance logic replacement, automotive sub-system controllers, sensor signal conditioning front-ends, and small embedded timing/sequencing tasks. The industrial temperature range permits deployment in uncontrolled environments, and the SSOP footprint suits dense PCB layouts where DIP-28 alternatives would consume too much board area.
When designing with this part, note that OTP memory requires pre-production programming; revisions cannot be field-deployed without physical replacement. The 4MHz top speed is adequate for slow control loops but limiting for any signal processing. Ensure decoupling caps of 0.1uF are placed near VDD and that unused I/O pins are configured as outputs to minimize current draw.
This page synthesizes distributor pricing, drop-in 28-SSOP alternatives, and practical design notes for the PIC16C55T-RCI/SS, giving engineers a faster sourcing decision than distributor catalog pages alone.
Drop-in alternatives for PIC16C55T-RCI/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-RCI/SS (same form factor and footprint) — differing in Oscillator Type, Program Memory Size, Program Memory Type, CPU Speed, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55T-RCE/SS
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC16C55-RCI/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55-HSI/SS
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →PIC16C55T-HS/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55T-HSI/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C55T-HSE/SS
✅ Drop-In✓ In Stock
$3.1 / Unit
View Datasheet →PIC16C55T-RCI/SS Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-Bit |
| CPU Speed | 4 MHz |
| Program Memory Size | 768 B (512 x 12) |
| Program Memory Type | OTP (One-Time Programmable) |
| RAM Size | 24 B |
| Number of I/O | 20 |
| Supply Voltage Range | 3 V to 6.25 V |
| Operating Temperature Range | -40 C to +85 C |
| Package / Case | 28-SSOP (5.30 mm width) |
| Mounting Type | Surface Mount |
| Oscillator Type | External (RC supported) |
| Peripherals | Watchdog Timer (WDT), Power-On Reset (POR) |
| Connectivity | - |
| Number of Timers | 1 x 8-bit |
| Instruction Set Architecture | PIC 12-bit baseline, RISC, 2-stage pipeline |
PIC16C55T-RCI/SS Pin Configuration
| Pin 1 | RA2 — Port A bit 2 (digital I/O) |
| Pin 2 | RA3 — Port A bit 3 (digital I/O) |
| Pin 3 | RTCC — Timer/counter input or port A bit 4 |
| Pin 4 | MCLR — Master clear reset input (active low) |
| 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 | RC0 — Port C bit 0 (digital I/O) |
| Pin 15 | RC1 — Port C bit 1 (digital I/O) |
| Pin 16 | RC2 — Port C bit 2 (digital I/O) |
| Pin 17 | RC3 — Port C bit 3 (digital I/O) |
| Pin 18 | RC4 — Port C bit 4 (digital I/O) |
| Pin 19 | RC5 — Port C bit 5 (digital I/O) |
| Pin 20 | VDD — Positive supply voltage (3V to 6.25V) |
| Pin 21 | RC6 — Port C bit 6 (digital I/O) |
| Pin 22 | RC7 — Port C bit 7 (digital I/O) |
| Pin 23 | OSC1 — Oscillator input (RC or crystal) |
| Pin 24 | OSC2 — Oscillator output (RC or crystal) |
| Pin 25 | RA0 — Port A bit 0 (digital I/O) |
| Pin 26 | RA1 — Port A bit 1 (digital I/O) |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | NC — Not connected (per datasheet) |
Typical Applications
PIC16C55T-RCI/SS is suitable for 6 applications: Industrial Automation Controllers, Consumer Appliance Logic Replacement, Automotive Sub-System Controllers, Sensor Signal Conditioning Front-Ends, Small Embedded Timing and Sequencing Tasks, Legacy Board Repair and Sustainment.
Industrial Automation Controllers
The PIC16C55T-RCI/SS fits industrial automation control modules where its 4MHz PIC core drives deterministic timing loops for relay sequencing, sensor multiplexing, and simple state machines. Twenty I/O pins handle digital inputs from limit switches and outputs to solenoids or indicator LEDs without external muxing. The industrial -40C to +85C temperature range tolerates factory-floor thermal swings, and the 28-SSOP outline permits dense PCB layouts inside sealed control enclosures. The 768B OTP program memory suits fixed-function logic replacement where firmware is finalized at production. Compared to discrete logic ICs, the integrated core reduces BOM count and PCB area.
Recommended
Consumer Appliance Logic Replacement
The PIC16C55T-RCI/SS replaces legacy CMOS logic gates in small consumer appliances such as coffee makers, washing machine sub-controllers, and microwave oven keypads. Its 20 I/O lines drive seven-segment displays, scan key matrices, and switch triac-triggered loads. The 4MHz instruction rate executes keypad scan routines and timing functions with single-cycle latency thanks to the PIC RISC architecture. Operating from a single 5V rail simplifies the analog supply chain. The 28-SSOP package lowers assembly cost versus DIP variants while still allowing hand-solder rework during prototype bring-up.
Recommended
Automotive Sub-System Controllers
The PIC16C55T-RCI/SS is suited to non-safety automotive sub-systems such as interior lighting controllers, seat memory modules, and HVAC damper drivers. The industrial -40C to +85C temperature range handles cabin and under-hood-near applications, and the CMOS core draws minimal quiescent current, supporting battery-drained vehicle storage scenarios. The 768B OTP holds fixed lighting patterns and timing sequences; the 8-bit timer generates PWM-like outputs for dimming and motor slew-rate control. PIC16C5X devices have a long automotive heritage and Microchip's lifecycle tools ease PPAP documentation for Tier 1 suppliers.
Recommended
Sensor Signal Conditioning Front-Ends
The PIC16C55T-RCI/SS serves as a low-cost digital front-end for sensor signal conditioning boards, digitizing thermistor, photodiode, or Hall-effect sensor inputs. Its 20 I/O lines can drive analog muxes, read comparator outputs, and pulse-width-modulate excitation sources for ratiometric measurement. The watchdog timer and power-on reset prevent sensor lock-ups in remote deployments. Although it lacks an integrated ADC, its 4MHz core can bit-bang simple sigma-delta conversion using external RC networks. The 28-SSOP package is well suited to small sensor PCBs where board area is constrained.
Recommended
Small Embedded Timing and Sequencing Tasks
The PIC16C55T-RCI/SS excels at replacing 555-timer cascades and small PAL/GAL sequencers in timing-critical applications. Its hardware 8-bit timer plus software loops can synthesize arbitrary delays, pulse trains, and watchdog-style sequencing. The deterministic PIC two-stage pipeline gives instruction-cycle-accurate timing without jitter from interrupt latency or cache misses. Operating voltage from 3V to 6.25V permits direct battery or 5V-rail deployment. The 28-SSOP industrial-temperature package makes the part attractive for outdoor lighting controllers, irrigation valves, and HVAC damper timing.
Recommended
Legacy Board Repair and Sustainment
The PIC16C55T-RCI/SS remains in demand for sustaining field-deployed equipment built in the 1990s and 2000s when this part was in mainstream production. Avionics sub-assemblies, industrial PLC I/O cards, and medical instrument controllers often use PIC16C5X OTP devices, and component-level repair is preferred over full board redesign. Distributors still carry limited allocation stock. Engineers performing repairs should verify date code and lot traceability to avoid counterfeit parts; sourcing through authorized channels such as DigiKey or Microchip Direct is recommended.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55T-RCI/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55T-RCE/SS | PIC16C55-RCI/SS | PIC16C55-HSI/SS | PIC16C55T-HS/SS | PIC16C55T-HSI/SS | PIC16C55T-HSE/SS |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | 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 | 28-SSOP - same |
| Core / Speed | 8-bit PIC, 4 MHz | 8-bit PIC, 4 MHz | 8-bit PIC, 4 MHz | 8-bit PIC, 4 MHz | 8-bit PIC, 4 MHz | 8-bit PIC, 4 MHz | 8-bit PIC, 4 MHz |
| Program Memory | 768 B OTP (512 x 12) | 768 B OTP (512 x 12) | 768 B OTP (512 x 12) | 768 B OTP (512 x 12) | 768 B OTP (512 x 12) | 768 B OTP (512 x 12) | 768 B OTP (512 x 12) |
| RAM | 24 B | 24 B | 24 B | 24 B | 24 B | 24 B | 24 B |
| I/O Pins | 20 | 20 | 20 | 20 | 20 | 20 | 20 |
| Supply Voltage | 3 V to 6.25 V | 3 V to 6.25 V | 3 V to 6.25 V | 3 V to 6.25 V | 3 V to 6.25 V | 3 V to 6.25 V | 3 V to 6.25 V |
| Oscillator Type | RC | RC | RC | Crystal/HS | Crystal/HS | Crystal/HS | Crystal/HS |
| Temperature Grade | Industrial (-40C to +85C) | Extended (0C to +70C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Commercial (0C to +70C) | Industrial (-40C to +85C) | Extended (0C to +70C) |
Key Differentiators
- Pin-to-pin drop-in alternatives within the same PIC16C5X family (vs PIC16F648A-I/SS)
- Industrial temperature grade option in the same package (vs PIC16C55T-RCE/SS)
- RC oscillator variant for low-cost timing without external crystal (vs PIC16C55T-HS/SS)
Design Notes
Place a 0.1uF decoupling capacitor within 1cm of the VDD pin (pin 20) and a bulk 10uF tantalum or ceramic capacitor at the board entry point. The PIC16C55T-RCI/SS draws brief current spikes during internal clock-edge transitions that can corrupt program execution if VDD droops below 3V. An RC filter (10 ohm + 10uF) on VDD helps reject supply rail noise injected by relay coils or motor drivers sharing the same 5V rail.
Do not assume OTP programming is reversible; once a PIC16C55T-RCI/SS is written, it cannot be erased or re-programmed. Always validate firmware on a flash equivalent (PIC16F505) or windowed UV-erase PIC16C55 before committing to OTP programming. The configuration word (oscillator selection, watchdog enable, code protect) is part of the OTP image and cannot be changed post-programming. Verify the configuration word matches your application requirements before final programming.
The 28-SSOP package has a 0.65mm pin pitch and 5.30mm body width per JEDEC MS-150. Reserve at least 4mm of board edge clearance around the part for pick-and-place nozzles and inspection access. Route MCLR (pin 4) directly to a reset supervisor or RC network - long traces pick up ESD and can trigger spurious resets. Keep OSC1/OSC2 traces short and surrounded by ground pour to minimize radiated clock harmonics.
Compliance Information
Compliance status not confirmed in verified web data; PIC16C5X OTP family predates many modern compliance programs. For new designs requiring RoHS compliance, migrate to PIC16F5X flash equivalents.
