PIC16C55A-20I/P - 8-Bit 20MHz OTP MCU 768B | Microchip
MPN: PIC16C55A-20I/P β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.48 | $2.48 |
| 10 | $2.3 | $23.00 |
| 100 | $2.05 | $205.00 |
| 500 | $1.82 | $910.00 |
| 1,000 | $1.6 | $1,600.00 |
PIC16C55A-20I/P Overview
A microcontroller (MCU) is a single-chip computer that contains a processor core, memory, and programmable input/output peripherals. The PIC16C5X family from Microchip Technology belongs to the broader category of 8-bit microcontrollers -> microcontrollers -> microprocessors -> semiconductors. These devices implement a RISC architecture with 33 single-word, single-cycle instructions and a 12-bit wide instruction word, achieving 2:1 code compression over competing 8-bit MCUs in the same price class.
Key features of the PIC16C55A-20I/P include a 20 MHz maximum clock speed, 20 MHz operating frequency, a two-level deep hardware stack, direct/indirect/relative addressing modes, and an 8-bit real-time clock/counter (TMR0) with 8-bit programmable prescaler. It supports a wide operating voltage range typical of the PIC16C5X family, with low power consumption suitable for battery and industrial applications.
From an architectural standpoint, the device uses a Harvard-style separated program and data bus, with the 12-bit instruction path enabling efficient encoding of arithmetic, branch, and bit-oriented operations in a single cycle. The PIC16C55A derivative of the PIC16C5X series offers expanded I/O (20 pins) and program memory (512 x 12) relative to the PIC16C54 base device, with OTP one-time-programmable EPROM for cost-sensitive production runs. Note: This device is marked as 'Not Recommended for new designs' (NRND) by Microchip; for new designs, Microchip recommends the PIC16F57-I/P family.
Typical applications include industrial control logic, automotive body electronics, simple sensor interfaces, appliance controls, and battery-powered instrument subsystems. The 20 MHz instruction execution rate and 20 GPIO make the device well-suited for tasks such as keypad scanning, LED driving, and low-speed serial protocols. Industrial temperature grade (-40C to +85C) extends its suitability to factory automation and outdoor equipment.
When designing with the PIC16C55A-20I/P, ensure the system clock source (RC oscillator, crystal, or resonator) matches the 20 MHz maximum rating, and respect the two-level hardware stack depth when writing interrupt or call-heavy code. Engineers targeting new designs should evaluate the Flash-based PIC16F57-I/P as a migration path that preserves pin-out while adding reprogrammability and longer-life cycle status.
This page synthesizes distributor stock levels, parametric equivalents, pricing tiers, and practical design notes not found in the manufacturer datasheet, enabling faster component selection and risk assessment for both new designs and legacy maintenance scenarios.
Drop-in alternatives for PIC16C55A-20I/P β 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 PIC16C55A-20I/P (same form factor and footprint) β differing in Operating Temperature, Package, Program Memory Size, Timers, Mounting Type.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C54A-20I/P
β Drop-Inβ In Stock
$1.38 / Unit
View Datasheet βPIC16C554-04I/P
β Drop-Inβ In Stock
$2.2 / Unit
View Datasheet βPIC16C554-20I/P
β Drop-Inπ Reference alternative (not in catalog)
PIC16C55A-04I/P
β Drop-Inπ Reference alternative (not in catalog)
PIC16F57-I/P
β Drop-Inπ Reference alternative (not in catalog)
PIC16C55A-20I/P Maximum Ratings & Electrical Characteristics
| Program Memory Size | 768 B (512 x 12) |
| Memory Type | OTP (One-Time Programmable EPROM) |
| RAM Size | 24 B |
| CPU Core | PIC 8-bit RISC |
| Instruction Set Width | 12-bit |
| Number of Instructions | 33 single-word/single-cycle |
| Maximum Clock Frequency | 20 MHz |
| Operating Supply Voltage | 2.5 V to 6.25 V (PIC16C5X family) |
| Number of I/O Pins | 20 |
| Timers | 1 x 8-bit (TMR0 with 8-bit prescaler) |
| Hardware Stack Depth | 2 levels |
| Package | 28-pin PDIP (DIP-28, 0.600 inch, 15.24 mm) |
| Mounting Type | Through-Hole (DIP) |
| Operating Temperature | -40 C to +85 C (Industrial) |
| Temperature Grade Code | I (Industrial) |
| Speed Grade | 20 MHz (suffix -20) |
| Data EEPROM | None (ROM-less data) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC16C55A-20I/P Pin Configuration
| Pin 1 | RA2 β Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 β Bidirectional I/O port A bit 3 |
| Pin 3 | T0CKI β Timer0 clock input / RA4 |
| Pin 4 | /MCLR β Master Clear (Reset) input, active low |
| Pin 5 | VSS β Ground reference |
| Pin 6 | RB0 β Bidirectional I/O port B bit 0 |
| Pin 7 | RB1 β Bidirectional I/O port B bit 1 |
| Pin 8 | RB2 β Bidirectional I/O port B bit 2 |
| Pin 9 | RB3 β Bidirectional I/O port B bit 3 |
| Pin 10 | RB4 β Bidirectional I/O port B bit 4 |
| Pin 11 | RB5 β Bidirectional I/O port B bit 5 |
| Pin 12 | RB6 β Bidirectional I/O port B bit 6 |
| Pin 13 | RB7 β Bidirectional I/O port B bit 7 |
| Pin 14 | VSS β Ground reference (secondary) |
| Pin 15 | OSC2 β Oscillator output (crystal/RC) |
| Pin 16 | OSC1 β Oscillator input (crystal/RC/external clock) |
| Pin 17 | VDD β Positive supply voltage |
| Pin 18 | RC0 β Bidirectional I/O port C bit 0 |
| Pin 19 | RC1 β Bidirectional I/O port C bit 1 |
| Pin 20 | RC2 β Bidirectional I/O port C bit 2 |
| Pin 21 | RC3 β Bidirectional I/O port C bit 3 |
| Pin 22 | RC4 β Bidirectional I/O port C bit 4 |
| Pin 23 | RC5 β Bidirectional I/O port C bit 5 |
| Pin 24 | RC6 β Bidirectional I/O port C bit 6 |
| Pin 25 | RC7 β Bidirectional I/O port C bit 7 |
| Pin 26 | RA0 β Bidirectional I/O port A bit 0 |
| Pin 27 | RA1 β Bidirectional I/O port A bit 1 |
| Pin 28 | VDD β Positive supply voltage (secondary) |
Typical Applications
PIC16C55A-20I/P is suitable for 6 applications: Industrial Control Logic, Appliance Control, Battery-Powered Instrumentation, Automotive Body Electronics, Remote Sensor Interface, Educational and Hobby Projects.
Industrial Control Logic
The PIC16C55A-20I/P fits industrial control logic applications thanks to its 20 GPIO pins and 20 MHz instruction rate. Its industrial temperature range (-40C to +85C) tolerates factory-floor heat. With 768 bytes of OTP program memory and 24 bytes RAM, it handles discrete I/O tasks such as relay sequencing, sensor debouncing, and PWM control loops. Engineers typically pair it with optocouplers for 24V industrial bus isolation.
Recommended
Appliance Control
White goods and small appliances use the PIC16C55A-20I/P for keypad scanning, LED/motor drive timing, and basic user-interface logic. Its 20 MHz CPU executes instructions in a single 200 ns cycle, sufficient for software UART bit-banging at 9600 baud to communicate with simple sensors. The 28-pin PDIP through-hole package simplifies hand-soldered prototyping in low-volume appliance designs.
Recommended
Battery-Powered Instrumentation
The PIC16C55A-20I/P suits battery-powered sensor instruments because the PIC16C5X architecture supports sleep and low-power operating modes drawing microamp-level quiescent current. A 20 MHz clock can be switched off between sensor reads, enabling multi-year battery life on a single lithium cell. The 24-byte RAM is enough to buffer a few sensor readings before transmission.
Recommended
Automotive Body Electronics
Although AEC-Q100 is not specified, the PIC16C55A-20I/P's industrial temperature grade and robust PIC architecture make it usable in non-critical automotive body electronics such as interior lighting controllers, mirror adjusters, and seat-position memory modules. Its 20 I/O pins directly drive LEDs, relays, and Hall-effect sensors. Designers should add TVS diodes for transient protection in 12V vehicle environments.
Recommended
Remote Sensor Interface
The PIC16C55A-20I/P serves as a sensor-interface MCU, reading analog signals through an external ADC and transmitting results via UART or simple bit-banged protocols. Its 5 MIPS throughput handles linearization math and CRC checksum generation for remote telemetry. The two-level hardware stack is adequate for shallow subroutines common in sensor-state-machine code.
Recommended
Educational and Hobby Projects
The PIC16C55A-20I/P is widely used in educational labs and hobbyist projects teaching 8-bit embedded programming. Its through-hole 28-pin PDIP package is breadboard-friendly, and the 20 MHz instruction rate makes timing experiments responsive. Students learn RISC concepts, OTP programming workflows, and assembly-level bit manipulation using MPLAB X IDE and the PICkit programmer family.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55A-20I/P β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C54A-20I/P | PIC16C554-04I/P | PIC16C554-20I/P | PIC16C55A-04I/P | PIC16F57-I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-pin PDIP (DIP-28) | 28-pin PDIP (DIP-28) - same | 28-pin PDIP (DIP-28) - same | 28-pin PDIP (DIP-28) - same | 28-pin PDIP (DIP-28) - same | 28-pin PDIP (DIP-28) - same |
| Max Clock Frequency | 20 MHz | 20 MHz | 4 MHz | 20 MHz | 4 MHz | 20 MHz |
| Program Memory | 768 B (512 x 12 OTP) | 384 B (256 x 12 OTP) | 768 B (512 x 12 OTP) | 768 B (512 x 12 OTP) | 768 B (512 x 12 OTP) | 3 KB (2K x 14 Flash) |
| RAM Size | 24 B | 24 B | 24 B | 24 B | 24 B | 72 B |
| Number of I/O Pins | 20 | 12 | 13 | 13 | 20 | 20 |
| Memory Type | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | Flash (reprogrammable) |
| Operating Temperature | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) | -40 C to +85 C (Industrial) |
| Lifecycle Status | NRND (Not Recommended for new designs) | NRND | NRND | NRND | NRND | Active |
Key Differentiators
- Largest OTP program memory in PIC16C5X 28-pin PDIP family (vs PIC16C54A-20I/P)
- Highest 8-bit throughput at 20 MHz in this PDIP package (vs PIC16C554-04I/P)
- Flash-based migration option with same PCB footprint (vs PIC16F57-I/P)
Design Notes
The PIC16C55A-20I/P has only a two-level hardware stack, which limits nested CALL depth. Subroutines that call other subroutines more than one level deep will overwrite the return PC and cause code to execute incorrectly. Flatten the call hierarchy or restructure with computed GOTOs to avoid stack overflow. This is a common issue when porting C code written for larger PIC18/PIC24 parts.
When laying out a 28-pin PDIP PCB, place the oscillator crystal or resonator as close to pins 15 (OSC2) and 16 (OSC1) as possible, with short traces to minimize stray capacitance. Keep digital signal traces away from the OSC1/OSC2 lines to avoid injected noise. A 1 M-ohm resistor across the crystal and 15-33 pF load capacitors (per crystal datasheet) ensure stable 20 MHz oscillation.
Add a 0.1 uF ceramic decoupling capacitor close to each VDD pin (pins 17 and 28) and a 10 uF bulk capacitor at the board power entry. The PIC16C55A's OTP EPROM programming mode requires a high-voltage VPP on pin 4 (/MCLR); ensure your programmer socket or ICP circuit can supply 13V nominal during programming without disrupting other supply rails.
Compliance Information
RoHS compliant per Microchip product page; lead-free PDIP package. Industrial temperature grade only - not AEC-Q100 qualified. For automotive applications, AEC-Q100-qualified PIC16F variants should be selected instead.
