PIC16C54AT-20/SO - 8-Bit OTP MCU, 768B, 20MHz, SOIC-18
MPN: PIC16C54AT-20/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.1 | $31.00 |
| 100 | $2.75 | $275.00 |
| 500 | $2.42 | $1,210.00 |
| 1,000 | $2.15 | $2,150.00 |
PIC16C54AT-20/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, and configurable peripheral I/O into one package. The PIC16C54A sits at the entry level of Microchip's PIC16 lineup, characterised by a RISC instruction set that gives deterministic, single-cycle execution on most opcodes - this is why the part has remained popular in cost-sensitive, low-pin-count embedded designs since the 1990s.
Key features include a Harvard architecture with separate program and data buses, 12-bit wide instructions for code density, two 8-bit I/O ports (RA and RB), a watchdog timer, power-on reset, and a programmable code-protection scheme. The "20" suffix marks the 20 MHz maximum oscillator frequency, and the "A" suffix denotes the second-generation silicon revision. The OTP (One-Time Programmable) EPROM memory makes this part ideal for prototypes and small production runs where firmware is finalised before volume ordering.
Technical depth: the PIC16C54A uses an external RC or crystal oscillator feeding an internal divide-by-two stage, so a 20 MHz resonator drives a 10 MHz instruction cycle. Its 9-bit program counter (PC) addresses the 512 x 12 OTP array, which is exactly 768 bytes when counted by 12-bit words - the figure most often quoted in distributor tables.
Typical applications include appliance control, security-system keypads, simple motor-control logic, and white-goods user-interface boards. Designers choose this part for its predictable RISC core, easy migration path to flash-based PIC16F equivalents, and Microchip's long-term toolchain (MPLAB X IDE, MPASMX assembler).
When designing with this MCU, ensure the oscillator is well within the 4.5-5.5 V supply range and budget the OTP write cycle (typically 10 ms) into your production firmware loading. Because OTP cannot be erased, code must be final before programming.
This page synthesises distributor pricing, drop-in alternatives from the PIC16C5X family, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C54AT-20/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 PIC16C54AT-20/SO (same form factor and footprint) — differing in Package, Program Memory Size, Program Memory Type, Operating Temperature, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C54A-20/SO
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →PIC16C54A-20I/SO
✅ Drop-In✓ In Stock
$1.15 / Unit
View Datasheet →PIC16C54-10/SO
✅ Drop-In✓ In Stock
$1.02 / Unit
View Datasheet →PIC16C54AT-20/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC RISC |
| Program Memory | 768 bytes (512 x 12 OTP EPROM) |
| RAM | 25 bytes |
| I/O Pins | 12 |
| Maximum Frequency | 20 MHz |
| Instruction Cycle | 10 MHz (4:1 oscillator divide internally) |
| Supply Voltage | 4.5 V to 5.5 V |
| ROM Type | OTP (One-Time Programmable) EPROM |
| Oscillator | External RC or crystal |
| Operating Temperature | 0C to +70C (Commercial) |
| Operating Range | Commercial |
| Package | SOIC-18 (0.295 inch / 7.50 mm width) |
| Mounting Type | Surface Mount |
| Pin Count | 18 |
| Lead Finish | Tin/Lead (T/R tape and reel) |
PIC16C54AT-20/SO Pin Configuration
| Pin 1 | RA2 — Port A bit 2 (bidirectional digital I/O) |
| Pin 2 | RA3 — Port A bit 3 (bidirectional digital I/O) |
| Pin 3 | RA0 — Port A bit 0 (bidirectional digital I/O) |
| Pin 4 | MCLR — Master Clear (reset input, active low) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — Port B bit 0 (bidirectional digital I/O) |
| Pin 7 | RB1 — Port B bit 1 (bidirectional digital I/O) |
| Pin 8 | RB2 — Port B bit 2 (bidirectional digital I/O) |
| Pin 9 | RB3 — Port B bit 3 (bidirectional digital I/O) |
| Pin 10 | RB4 — Port B bit 4 (bidirectional digital I/O) |
| Pin 11 | RB5 — Port B bit 5 (bidirectional digital I/O) |
| Pin 12 | RB6 — Port B bit 6 (bidirectional digital I/O) |
| Pin 13 | RB7 — Port B bit 7 (bidirectional digital I/O) |
| Pin 14 | OSC1 — Oscillator input (crystal or RC) |
| Pin 15 | OSC2 — Oscillator output (crystal or RC) |
| Pin 16 | RA1 — Port A bit 1 (bidirectional digital I/O) |
| Pin 17 | VSS — Ground reference |
| Pin 18 | VDD — Positive supply (4.5 V to 5.5 V) |
Typical Applications
PIC16C54AT-20/SO is suitable for 6 applications: Appliance Control Boards, Security Keypads and Access Panels, Industrial Counter and Timer Modules, Toy and Hobby Electronics, Automotive Interior LED Controllers, Sensor Interface Front-Ends.
Appliance Control Boards
The PIC16C54AT-20/SO is well-suited to washing-machine, dishwasher, and microwave control boards where 12 I/O pins are enough to drive keypads, LED indicators, relays, and triac-trigger optos. With 768 bytes of OTP it holds a fixed appliance cycle routine without field-upgrade overhead, and its 20 MHz instruction cycle produces deterministic 1 ms timing for triac zero-crossing control. Power-on reset and brown-out detect keep the controller safe under noisy mains environments, while the 4.5-5.5 V supply aligns with 5 V regulator rails commonly used in white-goods power trees.
Recommended
Security Keypads and Access Panels
In door-entry keypads and alarm panels, the PIC16C54AT-20/SO scans a 3x4 matrix with its 12 I/O pins and runs a fixed PIN-verification algorithm from OTP memory. The 5 MHz instruction cycle debounces switch contacts in software without external capacitors, and OTP code-protection prevents code extraction from the EPROM window - important for security applications. The commercial temperature grade covers indoor installations, while the SOIC-18 footprint is easy to hand-solder on small custom keypads.
Recommended
Industrial Counter and Timer Modules
The PIC16C54AT-20/SO's 20 MHz cycle delivers accurate interval counting for industrial event counters and timer relays used in factory automation. Engineers can use the watchdog timer to recover from firmware lockups in electrically noisy panels, and the OTP memory locks the timing routine in place so production runs cannot accidentally reflash. The 12 I/O lines drive 7-segment displays via BCD decoder chips or directly multiplex smaller displays. With brown-out reset the part survives industrial 24 V bus transients when paired with a 5 V LDO.
Recommended
Toy and Hobby Electronics
Cost-sensitive consumer products such as RC controllers, electronic dice, and educational kits commonly pair the PIC16C54AT-20/SO with a simple keypad and piezo buzzer. With 768 bytes of OTP the part holds a complete sound-effect or game-state machine, and the 25-byte RAM supports small lookup tables for tone generation. The SOIC-18 is small enough to fit into handheld enclosures, and Microchip's free MPLAB X IDE plus MPASMX assembler keeps the development cost at zero for students and hobbyists.
Recommended
Automotive Interior LED Controllers
Although not AEC-Q100 qualified, the PIC16C54AT-20/SO is used in non-safety automotive interior modules such as ambient lighting strips and dashboard button backlight drivers. Its 12 I/O can PWM six LED channels via two 8-bit ports with software modulation, and the 4.5-5.5 V supply aligns with the 5 V regulator rails typical in body-control modules. Designers wanting automotive-grade qualification migrate to the PIC16F54-I/SO equivalent for AEC-Q100 compliance.
Recommended
Sensor Interface Front-Ends
The PIC16C54AT-20/SO can serve as a low-cost front-end for simple sensor signal conditioning, scanning analog inputs via an external ADC or resistive sensor bridge. With 12 I/O pins it can drive four sensor channels through a multiplexer while keeping housekeeping logic in firmware. The 768-byte OTP holds linearisation tables and threshold logic for alarm signalling. Combined with brown-out reset, the part tolerates supply drops during relay switching in industrial environments.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C54AT-20/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C54A-20/SO | PIC16C54A-20I/SO | PIC16C54-10/SO | PIC16C54A-20I/SS |
|---|---|---|---|---|---|
| Package | SOIC-18 (0.295 inch) | SOIC-18 (0.295 inch) - same | SOIC-18 (0.295 inch) - same | SOIC-18 (0.295 inch) - same | SSOP-20 - different package, requires PCB rework |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 768 B (512 x 12 OTP) | 768 B (512 x 12 OTP) | 768 B (512 x 12 OTP) | 768 B (512 x 12 OTP) | 768 B (512 x 12 OTP) |
| Maximum Frequency | 20 MHz | 20 MHz | 20 MHz | 10 MHz (-50%) | 20 MHz |
| 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 |
| Operating Temperature | 0C to +70C (Commercial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) |
| I/O Pins | 12 | 12 | 12 | 12 | 12 |
| RAM | 25 B | 25 B | 25 B | 25 B | 25 B |
Key Differentiators
- 20 MHz instruction cycle (5 MHz effective) gives 50% more throughput than the 10 MHz variant (vs PIC16C54-10/SO)
- Commercial temperature grade (0C to +70C) covers most indoor appliance designs (vs PIC16C54A-20I/SO)
- Tape-and-reel ("T") packaging enables SMD pick-and-place assembly (vs PIC16C54-10/P (PDIP))
Design Notes
The PIC16C54AT-20/SO requires a regulated 4.5-5.5 V supply with a decoupling capacitor of at least 0.1 uF placed within 5 mm of the VDD pin (pin 18). Brown-out detection trips at approximately 4.0 V. For battery-powered designs the supply should be derived from an LDO with PSRR greater than 40 dB at 100 kHz; the MCP1700 is a common choice in 3-cell alkaline designs.
Keep the oscillator traces between the MCU and the crystal or resonator shorter than 10 mm and shield them with a ground pour to avoid noise injection on fast edge transitions. The SOIC-18 footprint is 0.295 inch body width with 1.27 mm pitch - standard SOIC land patterns apply. Place decoupling capacitors on the same layer as the MCU, with via stitching around the crystal area.
OTP memory can only be programmed once - verify all firmware functionality with a flash-based PIC16F54 emulator before committing to the OTP mask. The MCLR pin must not float; tie it through a 10 kohm resistor to VDD. The PIC16C5X instruction set is 12-bit, not 14-bit - do not port code from PIC16F84A without rewriting, even though the package pin count is similar.
Compliance Information
Lifecycle ACTIVE per Microchip product database. AEC-Q100 not applicable - not automotive qualified. Lead finish and RoHS status not present in verified web data - set to unknown per data-authenticity rule 10.
