PIC16C54A-20/SO - 8-Bit 20MHz OTP MCU 768B | Microchip
MPN: PIC16C54A-20/SO โ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.45 | $2.45 |
| 10 | $2.18 | $21.80 |
| 100 | $1.85 | $185.00 |
| 500 | $1.62 | $810.00 |
| 1,000 | $1.4 | $1,400.00 |
PIC16C54A-20/SO Overview
What is an 8-bit OTP microcontroller? An 8-bit OTP microcontroller is a small, fixed-instruction computer on a single IC that uses one-time-programmable EPROM for program storage - meaning the firmware can be written once and is non-volatile but not erasable. The PIC16C54A belongs to the microcontroller (MCU) hypernym hierarchy: microcontroller โ 8-bit MCU โ RISC MCU โ CMOS MCU โ EPROM/ROM-based MCU โ OTP MCU. This family targets cost-sensitive embedded control where flash reprogrammability is unnecessary and a small, deterministic instruction set is preferred.
Key features of the PIC16C54A include a two-level hardware stack for subroutine nesting, direct/indirect/relative addressing modes, an 8-bit real-time clock/counter (TMR0) with programmable prescaler, and seven or eight special-function hardware registers for peripheral control. The architecture uses Harvard-style separate program/data buses, single-cycle instruction execution (except branches), and 12-bit-wide instruction words optimized for compact code density. Watchdog timer with on-chip RC oscillator and power-on reset are standard features that simplify external circuitry.
The PIC16C54A-20/SO uses a CMOS process with fully static operation, allowing the clock to be stopped without losing register state. Its low-power CMOS design and EPROM-based program memory make it well suited for high-volume, cost-sensitive consumer and industrial control applications where code is finalized at production. The 'A' revision improved oscillator stability and reduced current consumption versus the original PIC16C54.
Typical applications include appliance controls, security system sensor interfaces, simple timer/counter subsystems, LED drivers, automotive body electronics, and remote-control transmitters. The wide software base and stable instruction set also make it popular for educational and hobbyist embedded projects where a simple, deterministic core is preferred over modern flash-based MCUs.
When designing with this part, note that OTP memory cannot be re-programmed in-circuit. For prototyping or field-updatable designs, Microchip recommends the pin-compatible flash-based PIC16F54. The 18-SOIC package has a 7.50mm body width and supports standard surface-mount assembly.
This page synthesizes distributor pricing, parametric cross-references, and practical design notes not found in the manufacturer datasheet alone, helping engineers evaluate the PIC16C54A-20/SO for both new designs and legacy maintenance scenarios.
Drop-in alternatives for PIC16C54A-20/SO โ 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 PIC16C54A-20/SO (same form factor and footprint) โ differing in RoHS Status, Package, Timers, Core Architecture, Instruction Cycle.
Quick Comparison Tool โ Select alternative parts for side-by-side comparison:
PIC16F54-I/SO
โ Drop-In๐ Reference alternative (not in catalog)
PIC16C54A-20I/SO
โ Drop-Inโ In Stock
$1.15 / Unit
View Datasheet โPIC16C54A-20E/SO
โ Drop-In๐ Reference alternative (not in catalog)
PIC16C54A-04/SO
โ Drop-In๐ Reference alternative (not in catalog)
PIC16C54A-10/SO
โ Drop-In๐ Reference alternative (not in catalog)
PIC16C54A-20/SO Maximum Ratings & Electrical Characteristics
| Core | PIC16C5X 8-bit RISC |
| Program Memory Size | 768 B (512 x 12) |
| Program Memory Type | OTP (One-Time-Programmable EPROM) |
| RAM Size | 25 B |
| Maximum Clock Frequency | 20 MHz |
| Supply Voltage Range | 4.5 V to 5.5 V |
| Number of I/O Pins | 12 |
| Instruction Word Width | 12-bit |
| Data Bus Width | 8-bit |
| Timers | 1 x 8-bit (TMR0) with prescaler |
| Hardware Stack | 2-level |
| Watchdog Timer | Yes (on-chip RC oscillator) |
| Operating Temperature Range | 0C to +70C (Commercial) |
| Package | 18-SOIC (7.50 mm body width) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Non-Compliant (contains Pb) |
PIC16C54A-20/SO Pin Configuration
| Pin 1 | RA2 โ Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 โ Bidirectional I/O port A bit 3 |
| Pin 3 | RA4/TOCKI โ Bidirectional I/O port A bit 4 / TMR0 clock input |
| Pin 4 | MCLR โ Master Clear reset input (active low) |
| Pin 5 | VSS โ Ground reference |
| Pin 6 | OSC2/CLKOUT โ Oscillator crystal output / CLKOUT |
| Pin 7 | OSC1/CLKIN โ Oscillator crystal input / external clock input |
| Pin 8 | RB0/INT โ Bidirectional I/O port B bit 0 / external interrupt input |
| Pin 9 | RB1 โ Bidirectional I/O port B bit 1 |
| Pin 10 | RB2 โ Bidirectional I/O port B bit 2 |
| Pin 11 | RB3 โ Bidirectional I/O port B bit 3 |
| Pin 12 | RB4 โ Bidirectional I/O port B bit 4 |
| Pin 13 | RB5 โ Bidirectional I/O port B bit 5 |
| Pin 14 | VDD โ Positive supply voltage (+5V) |
| Pin 15 | OSC1/RC0 โ OSC1 alternate function / RC0 I/O |
| Pin 16 | RC1 โ Bidirectional I/O port C bit 1 |
| Pin 17 | RC2 โ Bidirectional I/O port C bit 2 |
| Pin 18 | RC3 โ Bidirectional I/O port C bit 3 |
Typical Applications
PIC16C54A-20/SO is suitable for 7 applications: Appliance Cycle Controller, PIR Security Sensor Interface, Automotive Body Electronics, Remote Control Transmitter, LED Lighting Controller, Battery Charger Controller, Educational / Hobbyist Embedded Platform.
Appliance Cycle Controller
The PIC16C54A-20/SO fits appliance cycle controllers such as washing machine, dishwasher, and microwave oven timers where deterministic timing and minimal BOM cost are essential. Its 8-bit 12-bit-instruction PIC16C5X core delivers 5 MIPS at the 20 MHz clock speed, easily handling relay sequencing, LED indicator multiplexing, and button-debounce state machines. The 768-byte OTP EPROM holds the complete firmware image with no external memory required, and the 12 I/O pins directly drive relays, triac optocouplers, and 7-segment displays. The 4.5V-5.5V supply matches standard 5V appliance rails, and the commercial 0C to +70C range covers indoor kitchen and laundry environments. OTP memory is a natural fit because appliance firmware is frozen at production.
Recommended
PIR Security Sensor Interface
The PIC16C54A-20/SO is well matched to PIR motion detector signal-conditioning boards in security alarm panels. Its single TMR0 8-bit timer with programmable prescaler generates precise 1-second to 1-minute debounce intervals for PIR pulse-pair validation, eliminating false triggers from thermal noise. The 25-byte RAM is sufficient for a small state machine tracking alarm/warm-up/test/armed modes, while the 12-bit instruction set keeps the C-equivalent source code under 400 instructions - well within the 768-byte OTP budget. The 20 MHz clock provides responsive handling of multiple sensor zones, and the 4.5V-5.5V supply is compatible with alarm-panel 5V rails including battery-backed standby. OTP ensures the firmware cannot be tampered with in the field.
Recommended
Automotive Body Electronics
The PIC16C54A-20/SO targets cost-sensitive automotive body controllers such as window lift switches, mirror position controllers, and seat-memory modules where deterministic response and small package count matter more than flash flexibility. The 12 I/O pins handle switch scanning, motor direction relays, and LED feedback without external mux logic. Its 20 MHz instruction rate delivers sub-millisecond response for anti-pinch algorithms on window lifts. The OTP memory prevents field firmware tampering - important for safety-certified body electronics. For underhood or engine-bay modules, the industrial-grade PIC16C54A-20I/SO (same 18-SOIC footprint, -40C to +85C) provides wider thermal margin. Note that 5V supply must be regulated from the automotive 12V/24V battery bus with load-dump protection.
Recommended
Remote Control Transmitter
The PIC16C54A-20/SO fits low-cost RF/IR remote control transmitters for garage door openers, ceiling fans, key fobs, and consumer AV equipment. Its small 768-byte OTP holds rolling-code or fixed-code transmission tables, while 25-byte RAM is sufficient for buffer-and-transmit state. The 12 I/O pins directly interface a 4x4 keypad matrix (8 lines), with 4 spare pins for status LEDs and an RF/IR transmitter enable. The PIC16C5X 12-bit instruction set keeps timing-critical transmission routines short and deterministic - critical for IR RC-5 or RF Manchester encoders where bit timing is enforced in firmware. Low CMOS quiescent current extends battery life in coin-cell powered key fobs.
Recommended
LED Lighting Controller
The PIC16C54A-20/SO drives simple LED lighting controllers such as decorative RGB string controllers, aquarium light timers, and architectural color-changing fixtures. Its TMR0 with prescaler generates PWM frequencies above 100 Hz to avoid visible flicker, while 12 I/O pins multiplex three or four PWM channels directly without external driver logic. The 20 MHz clock supports 8-bit PWM resolution at refresh rates that exceed visual perception thresholds. Commercial 0C to +70C range suits indoor architectural installations, and OTP memory locks in the lighting sequence to prevent field tampering with safety-critical sequences. The 4.5V-5.5V supply is compatible with standard USB-derived 5V LED driver rails.
Recommended
Battery Charger Controller
The PIC16C54A-20/SO is suitable for low-power NiCd/NiMH and small Li-ion charger controllers in cordless phones, electric toothbrushes, and handheld vacuum battery packs. Its TMR0 with prescaler implements accurate charge-time and -termination algorithms, while the 12-bit instruction set keeps CC/CV state-machine code compact. The 25-byte RAM holds cell voltage sample averages and charge cycle counters. The PIC16C5X deterministic single-cycle instructions make ADC-free voltage threshold checks via on-chip comparator reliable and repeatable. The 20 MHz clock samples thermistor and cell voltage frequently enough to detect thermal runaway within seconds. OTP memory locks in the charge profile and prevents unauthorized firmware modifications that could create safety hazards.
Recommended
Educational / Hobbyist Embedded Platform
The PIC16C54A-20/SO is widely used in introductory embedded systems courses, hobbyist projects, and DIY electronics kits because its PIC16C5X 12-bit instruction set is small (33 instructions) and easy to teach. The 20 MHz clock with 5 MIPS instruction throughput is fast enough for meaningful real-time tasks (servo control, sensor reading, UART bit-banging) yet slow enough to follow on a logic analyzer. The 768-byte OTP and 25-byte RAM provide a deliberately constrained environment that teaches resource-aware programming - foundational skill for any embedded engineer. Despite OTP being non-reprogrammable, low unit cost (USD 1-2 at qty 1) makes each student project affordable. The 18-SOIC package also fits standard 18-pin DIP adapter boards for breadboard prototyping.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C54A-20/SO โ comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F54-I/SO | PIC16C54A-20I/SO | PIC16C54A-20E/SO | PIC16C54A-04/SO | PIC16C54A-10/SO |
|---|---|---|---|---|---|---|
| Package | 18-SOIC | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 768 B OTP | 768 B Flash | 768 B OTP | 768 B OTP | 768 B OTP | 768 B OTP |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 4 MHz | 10 MHz |
| Temperature Grade | Commercial (0C to +70C) | Industrial (-40C to +85C) | Industrial (-40C to +85C) | Extended (-40C to +125C) | Commercial | Commercial |
| RAM | 25 B | 25 B | 25 B | 25 B | 25 B | 25 B |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 12 |
| Lifecycle Status | NRND | Active | NRND | NRND | NRND | NRND |
| Memory Type | OTP EPROM | Flash (reprogrammable) | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM |
Key Differentiators
- Reprogrammable flash memory vs OTP (vs PIC16F54-I/SO)
- Wider temperature range option for harsh environments (vs PIC16C54A-20I/SO (Industrial grade))
- Lower cost per unit in high-volume production (vs PIC16C54A-04/SO (4 MHz version))
Design Notes
The PIC16C54A uses One-Time-Programmable EPROM - firmware cannot be erased or re-written after the initial programming. This means any firmware bug discovered after programming requires the entire chip to be replaced, not reflashed. For development, prototype with the flash-based PIC16F54-I/SO (same 18-SOIC pinout) and only commit to PIC16C54A-20/SO for production runs after firmware is fully validated. Estimated cost impact: OTP allows 30-50% unit-cost savings over flash, but with no field-updatability.
The PIC16C54A requires a regulated 4.5V to 5.5V supply. A 100nF ceramic decoupling capacitor must be placed within 5mm of the VDD pin (pin 14) with a short, wide PCB trace to VSS (pin 5). In noisy environments (relay boards, motor control), add a 10uF tantalum or aluminum polymer bulk capacitor on the same 5V rail. Avoid switching the regulator off and on rapidly - the EPROM programming margin can be affected by slow VDD rise times below 100 us. Brown-out detection must use the internal BOD circuit configured at 4.5V.
The 18-SOIC package has a 7.50 mm body width (300 mil) - the wide-body SOIC variant, NOT the 3.9 mm (150 mil) narrow SOIC. Verify your PCB land pattern matches the wide SOIC footprint, otherwise pins will not align with pads. Keep analog and digital ground separated if the design mixes analog sensing with digital logic - connect grounds at a single point near the MCU VSS pin. Place the crystal/oscillator within 10 mm of OSC1/OSC2 with guard traces to reduce EMI. For programming header, dedicate a 5-pin in-circuit serial programming (ICSP) header on production boards even though OTP precludes field updates - useful for factory programming and quality verification.
OSC1 and OSC2 traces must be kept short (under 10 mm) and surrounded by a ground guard ring to prevent the oscillator from picking up digital switching noise. When using an external clock source instead of a crystal, drive OSC1 with a clean CMOS-level signal (rise/fall times under 50 ns) and leave OSC2 floating. The MCLR pin must have a 10 kohm pull-up to VDD with a 100 nF capacitor to ground for power-on reset; do not leave MCLR floating even if it appears to work in prototypes, as noise can cause spurious resets. All I/O pins default to high-impedance input on POR and require TRIS register configuration before use.
Estimated: The PIC16C54A-20/SO has a typical operating power consumption of approximately 10 mA at 20 MHz and 5V (50 mW), plus quiescent current under 1 mA in sleep. The 18-SOIC package has a theta_JA of approximately 85 C/W, giving a junction temperature rise of only 4.25 C above ambient at full operation - well within the 0C to +70C commercial range. No heatsink or thermal management is required. However, in sealed enclosures without airflow, ambient temperature may exceed 70C and the PIC16C54A-20I/SO industrial-temperature variant should be used instead. The PIC16C54A-20E/SO extended variant supports -40C to +125C for underhood automotive deployments.
Compliance Information
PIC16C54A-20/SO is not RoHS compliant due to lead-bearing solder finish on the 18-SOIC pins. For RoHS-compliant designs, use PIC16F54-I/SO (lead-free). Not AEC-Q100 qualified - choose PIC16C54A-20I/SO or PIC16C54A-20E/SO with automotive-grade testing for automotive applications.
