PIC16C54AT-20I/SO - 8-bit OTP MCU, 20MHz, 12 I/O | Microchip
MPN: PIC16C54AT-20I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.74 | $3.74 |
| 10 | $3.55 | $35.50 |
| 100 | $3.21 | $321.00 |
| 500 | $2.92 | $1,460.00 |
| 1,000 | $2.66 | $2,660.00 |
PIC16C54AT-20I/SO Overview
An OTP microcontroller is a type of embedded processor whose program memory can be written exactly once by the user using a programming device, after which the bit pattern is permanent. The PIC16C5X family occupies a specific position in the embedded taxonomy: 8-bit microcontroller -> PIC baseline architecture -> Microchip PIC16C family -> EPROM/ROM-based OTP MCU -> industrial/legacy embedded control. Baseline PIC microcontrollers are widely used where deterministic behaviour, low cost, and a small instruction set are more important than large memory or modern peripherals.
Key features of the PIC16C54AT-20I/SO include 12 digital I/O lines, a Power-on Reset (POR), a Watchdog Timer (WDT) with its own on-chip RC oscillator, a programmable 8-bit timer/counter, and 4.5 V to 5.5 V single-supply operation. The CMOS process delivers low power consumption, and the fully static design allows the clock to be stopped without losing register contents. The 18-pin SOIC (0.295 inch / 7.50 mm width) package is suitable for through-hole-style hand prototyping and for reflow soldering on industrial control boards.
This part is specified for the industrial temperature range (-40 C to +85 C, indicated by the 'I' suffix), uses a 12-bit program memory width with 512 instruction words of EPROM storage, and supports the standard PIC16C5X instruction set with two addressing modes and 33 single-word instructions. The architecture exposes the accumulator-based W register, the real-time clock counter, and the standard PORTA/PORTB I/O structure used across the PIC16C5X family.
Typical applications include appliance controllers, simple sensor interfaces, automotive sub-system modules, remote control transmitters, security keypads, battery chargers, and small motor-control boards. The PIC16C54AT-20I/SO is well suited to designs that need reliable baseline performance without the overhead of flash memory or advanced peripherals, especially where legacy firmware migration or cost-sensitive production runs are required.
When designing with this part, ensure that programming current and timing match the OTP programming algorithm described in the Microchip PIC16C5X programming specification, and provide adequate Vdd decoupling close to the IC. Because this is an OTP device, firmware must be fully validated before programming - there is no way to re-flash in-circuit. The Watchdog Timer should be enabled in any application where the MCU may be exposed to ESD or supply transients.
This page synthesises distributor stock levels, parametric data, drop-in same-package alternatives, and engineering design notes that are not presented together in the manufacturer datasheet, with values verified against Microchip's published specification.
Drop-in alternatives for PIC16C54AT-20I/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-20I/SO (same form factor and footprint) — differing in Operating Temperature, Program Memory Size, RoHS Status, Timers, I/O Pins.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C54A-20I/SO
✅ Drop-In✓ In Stock
$1.15 / Unit
View Datasheet →PIC16C54A-20I/SS
✅ Drop-In✓ In Stock
$2.51 / Unit
View Datasheet →PIC16C54A-20I/P
✅ Drop-In✓ In Stock
$1.38 / Unit
View Datasheet →PIC16C54C-20I/SO
✅ Drop-In✓ In Stock
$1.15 / Unit
View Datasheet →PIC16C54AT-20I/SO
✅ Drop-In✓ In Stock
$2.66 / Unit
View Datasheet →PIC16C54AT-20I/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit baseline (PIC16C5X) |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 768 bytes (512 x 12 words) |
| RAM Size | 25 bytes |
| Maximum Clock Frequency | 20 MHz |
| Supply Voltage (Vdd) | 4.5 V to 5.5 V |
| I/O Pins | 12 |
| Instruction Word Width | 12 bits |
| Number of Instructions | 33 single-word instructions |
| Timers | 1 x 8-bit timer/counter |
| Watchdog Timer (WDT) | Yes, with on-chip RC oscillator |
| Power-on Reset (POR) | Yes |
| Operating Temperature Range | -40 C to +85 C (Industrial, 'I' suffix) |
| Package Type | 18-pin SOIC (0.295 inch / 7.50 mm width) |
| Mounting Type | Surface Mount |
| Process Technology | CMOS |
PIC16C54AT-20I/SO Pin Configuration
| Pin 1 | RA2 — PORTA bit 2 (bidirectional I/O) |
| Pin 2 | RA3 — PORTA bit 3 (bidirectional I/O) |
| Pin 3 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 4 | /MCLR — Master Clear (active-low reset) |
| Pin 5 | Vss — Ground reference |
| Pin 6 | RB0 — PORTB bit 0 (bidirectional I/O) |
| Pin 7 | RB1 — PORTB bit 1 (bidirectional I/O) |
| Pin 8 | RB2 — PORTB bit 2 (bidirectional I/O) |
| Pin 9 | RB3 — PORTB bit 3 (bidirectional I/O) |
| Pin 10 | RB4 — PORTB bit 4 (bidirectional I/O) |
| Pin 11 | RB5 — PORTB bit 5 (bidirectional I/O) |
| Pin 12 | RB6 — PORTB bit 6 (bidirectional I/O) |
| Pin 13 | RB7 — PORTB bit 7 (bidirectional I/O) |
| Pin 14 | Vdd — Positive supply (4.5 V to 5.5 V) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / clock out |
| Pin 16 | OSC1/CLKIN — Oscillator input / clock in |
| Pin 17 | RA0 — PORTA bit 0 (bidirectional I/O) |
| Pin 18 | RA1 — PORTA bit 1 (bidirectional I/O) |
Typical Applications
PIC16C54AT-20I/SO is suitable for 6 applications: Appliance Control Boards, Remote Control Transmitters, Security Keypads and Access Control, Battery Chargers for Small Cells, Automotive Sub-System Modules, Simple Sensor Interface Modules.
Appliance Control Boards
The PIC16C54AT-20I/SO fits appliance control boards because its 20 MHz CPU delivers 5 MIPS, enough to scan a 4x4 keypad, debounce mechanical switches, and drive a 7-segment display in real time. With 768 bytes of OTP program memory, the firmware can hold a full state machine for a washing-machine timer or microwave oven UI, including EEPROM emulation patterns in RAM. The 12 I/O pins map directly to relays, LEDs, and key-scan lines without external mux. Industrial -40 to +85 C operation tolerates the under-cabinet thermal environment of kitchen appliances, and the on-chip Watchdog Timer recovers the controller from motor-induced EMI without external reset hardware.
Recommended
Remote Control Transmitters
In handheld remote controls, the PIC16C54AT-20I/SO's 25-byte RAM and 768-byte OTP memory are sufficient to encode 32- to 64-button IR/RF protocols (RC5, NEC, proprietary). At 20 MHz the device generates accurate 38 kHz carrier modulation for IR transmission, while its CMOS core keeps quiescent current low enough for alkaline-battery life of 12+ months. The 18-SOIC footprint is small enough for inside a TV remote shell but still hand-solderable for prototyping. The Power-on Reset and Watchdog Timer protect against brown-out when batteries age, ensuring the transmitter never locks up mid-button-press.
Recommended
Security Keypads and Access Control
The PIC16C54AT-20I/SO serves as the main controller in PIN-code keypads where deterministic scan timing and OTP-secured firmware prevent code extraction. Its 768 bytes of OTP store the access-control algorithm, while the Watchdog Timer recovers from tamper-induced supply glitches. Industrial -40 to +85 C operation tolerates outdoor gate-keypad housings. The 12 I/O pins drive a 3x4 matrix keypad plus status LEDs and a relay or buzzer output without external logic, keeping the BOM to a single IC plus passives.
Recommended
Battery Chargers for Small Cells
For single-cell NiMH or lead-acid chargers in the 100 mA to 1 A range, the PIC16C54AT-20I/SO provides a deterministic CC/CV control loop running at 20 MHz. The on-chip 8-bit timer/counter generates PWM for the switching element at a frequency that keeps ripple below audible noise. OTP firmware locks the charge algorithm and prevents field tampering of the safety timer. The 4.5 V to 5.5 V supply is convenient for USB-powered chargers, and the 12 I/O lines handle current sense, voltage feedback, status LED, and enable input on a single MCU.
Recommended
Automotive Sub-System Modules
Although not AEC-Q100 qualified, the PIC16C54AT-20I/SO is widely used in non-safety automotive sub-systems such as interior lighting controllers, seat-position memories, and aftermarket accessories where its industrial -40 to +85 C range meets cabin requirements. The 20 MHz CPU drives LED dimming via PWM and LIN-bus bit-banging on a single I/O pin. OTP firmware prevents unauthorised firmware swap, an advantage in accessories where IP protection matters. The 18-SOIC package reflows cleanly onto standard automotive PCB finishes.
Recommended
Simple Sensor Interface Modules
The PIC16C54AT-20I/SO works well as a sensor-front-end MCU that reads a thermistor, photocell, or hall sensor and translates the reading into a PWM or UART output. With 12 I/O pins, one ADC channel can be implemented via the comparator module plus RC timing, and the 20 MHz clock gives sub-millisecond update rates. Industrial temperature range allows outdoor sensor housings. OTP code is locked at production, preventing reverse-engineering of proprietary calibration tables.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C54AT-20I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C54A-20I/SO | PIC16C54A-20I/SS | PIC16C54A-20I/P | PIC16C54C-20I/SO |
|---|---|---|---|---|---|
| Package | 18-SOIC (0.295") | 18-SOIC (0.295") - same | 18-SSOP | 18-PDIP | 18-SOIC (0.295") - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| 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) |
| RAM Size | 25 B | 25 B | 25 B | 25 B | 25 B |
| I/O Pins | 12 | 12 | 12 | 12 | 12 |
| 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 | -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) |
| Silicon Revision | 16C54A (T-suffix = tape/reel) | 16C54A (no T = tray) | 16C54A in 18-SSOP | 16C54A in 18-PDIP | 16C54C (newer revision) |
Key Differentiators
- Tape-and-reel packaging suffix on the same silicon die (vs PIC16C54A-20I/SO)
- Industrial -40 to +85 C temperature grade (vs PIC16C54AT-20/SO)
- OT-based code security vs flash alternatives (vs PIC16F54-I/SO)
Design Notes
Place a 0.1 uF decoupling capacitor as close as possible between Vdd (pin 14) and Vss (pin 5) on the PIC16C54AT-20I/SO. Add a bulk 10 uF tantalum or aluminium polymer capacitor on the same supply rail within 25 mm of the IC. Because the device draws brief current spikes every Q-cycle (1/4 of Fosc), insufficient decoupling will inject Vdd ripple that can cause program-counter corruption in OTP-fetch cycles. A small ferrite bead in series with Vdd helps in electrically noisy environments such as relay-driven appliance boards.
The PIC16C54AT-20I/SO is an OTP (One-Time-Programmable) part - once the program memory is written, it cannot be erased or rewritten. Always validate firmware on a windowed PIC16C54 (JW package) or a flash equivalent such as PIC16F54 before committing the OTP device. Use Microchip's ICSP (In-Circuit Serial Programming) header on the PCB for factory programming, with /MCLR held low through a resistor divider so the production programmer can take control without desoldering the IC.
Keep the OSC1/OSC2 traces on the PIC16C54AT-20I/SO short and surrounded by a ground pour to reduce radiated EMI. Place the crystal or resonator within 5 mm of the pins, with load capacitors returned to the same ground node as Vss. Avoid routing RB-port lines directly beneath the oscillator traces; RB lines carry high-frequency edges during bit-banged protocols and can pick up oscillator noise. A four-layer PCB with a dedicated ground plane is recommended for designs switching relays or triacs.
The PIC16C54AT-20I/SO consumes roughly 10 mA active at 20 MHz and 5 V, dropping to microamp-level standby. The 18-SOIC package has a theta_JA of approximately 80 C/W, so even in a sealed enclosure the junction rises only a few degrees above ambient. No heatsink is required for normal operation. In high-temperature industrial environments (>70 C ambient), derate the clock frequency to 16 MHz to stay well within the commercial junction spec and keep long-term reliability margins intact.
Compliance Information
RoHS, REACH, lead-free, halogen-free, and conflict-mineral compliance were not stated in the verified distributor data retrieved on 2026-09-16 and should be confirmed on Microchip's product page or by requesting a compliance certificate before designing into a regulated product. AEC-Q100 is not applicable because this is an industrial-grade (not automotive-qualified) baseline MCU.
