PIC16LC54AT-04/SS - 8-Bit 4MHz OTP MCU, 768B | Microchip
MPN: PIC16LC54AT-04/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.83 | $1.83 |
| 10 | $1.65 | $16.50 |
| 100 | $1.4 | $140.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $0.99 | $990.00 |
| 3,000 | $0.86 | $2,580.00 |
PIC16LC54AT-04/SS Overview
What is an OTP microcontroller? An OTP (One-Time-Programmable) microcontroller contains program memory that can be written exactly once using a programming voltage, after which the bit pattern is permanent. OTP MCUs sit between fully-mask-ROM parts (cheapest at volume, but require a full mask NRE) and flash-based MCUs (re-programmable in-circuit). For low-to-mid-volume production runs where firmware must be locked at the factory and field updates are not required, OTP offers the lowest unit cost while preserving the flexibility of late-stage firmware changes during development.
Key features of the PIC16LC54AT-04/SS include 4 MHz maximum clock, fully static CMOS design allowing clock-stopped operation for ultra-low standby power, a programmable code-protection bit, a watchdog timer with on-chip RC oscillator, and a power-on reset (POR) circuit. The 12-bit wide, highly symmetrical instruction set reduces development time and produces compact code density - a hallmark of the PIC16C5X architecture. The device also offers an internal MCLR reset and four oscillator options selectable at programming time (RC, LP, XT, HS).
Architecturally, the PIC16LC54A uses a Harvard-style design with separate program and data buses, a 2-level deep hardware stack, and a single 8-bit ALU. Unlike its modern PIC16F successors, the PIC16LC54A does not support interrupts - the program counter simply loops through software branches. This makes the core deterministic and well-suited to simple state-machine and timing-control applications where interrupt latency would add unnecessary complexity.
Typical applications include low-cost consumer appliances, battery-powered sensor transmitters, simple motor and relay controllers, replacement of discrete logic in legacy designs, LED display drivers, and remote-control transmitters. The wide 3.0 V to 6.25 V supply range also suits industrial 5 V systems, while the low-power CMOS core allows long-life operation from 2-3 AA cells.
When designing with this part, note that the OTP memory means firmware bugs require a board re-spin - use the PIC16F54 flash equivalent (same pinout) for prototyping and the PIC16LC54AT-04/SS only after firmware is finalized. The 20-SSOP package has a 0.65 mm pitch and requires standard surface-mount reflow.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on the manufacturer datasheet, giving you a single-source engineering reference for the PIC16LC54AT-04/SS.
Drop-in alternatives for PIC16LC54AT-04/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 PIC16LC54AT-04/SS (same form factor and footprint) — differing in Package, Core Architecture, Family, Operating Temperature, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16LC54A-04/SS
✅ Drop-In✓ In Stock
$3.85 / Unit
View Datasheet →PIC16LC54A-04E/SS
✅ Drop-In✓ In Stock
$2.84 / Unit
View Datasheet →PIC16F54T-I/SS
✅ Drop-In✓ In Stock
$0.34 / Unit
View Datasheet →PIC16C54AT-04E/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C54AT-04I/SS
✅ Drop-In✓ In Stock
$1.21 / Unit
View Datasheet →PIC16LC54AT-04/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit, Harvard |
| Family | PIC16C5X (PIC16LC54A sub-family) |
| Program Memory Type | OTP (One-Time-Programmable EPROM) |
| Program Memory Size | 768 bytes (512 x 12 words) |
| RAM | 25 bytes |
| Maximum CPU Clock | 4 MHz |
| Supply Voltage (Vdd) | 3.0 V to 6.25 V |
| I/O Pins | 12 |
| Instruction Width | 12 bits |
| Stack Depth | 2 levels (hardware) |
| Interrupts | None |
| Watchdog Timer | Yes (with on-chip RC oscillator) |
| Power-On Reset | Yes (POR) |
| Code Protection | Yes (programmable) |
| Oscillator Modes | RC, LP, XT, HS (selected at programming) |
| Package | 20-pin SSOP (5.30 mm body, 0.65 mm pitch) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (industrial) |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC16LC54AT-04/SS Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O port A bit 3 |
| Pin 3 | RB0 — Bidirectional I/O port B bit 0 |
| Pin 4 | RB1 — Bidirectional I/O port B bit 1 |
| Pin 5 | RB2 — Bidirectional I/O port B bit 2 |
| Pin 6 | RB3 — Bidirectional I/O port B bit 3 |
| Pin 7 | RB4 — Bidirectional I/O port B bit 4 |
| Pin 8 | RB5 — Bidirectional I/O port B bit 5 |
| Pin 9 | RB6 — Bidirectional I/O port B bit 6 |
| Pin 10 | RB7 — Bidirectional I/O port B bit 7 |
| Pin 11 | VSS — Ground reference |
| Pin 12 | OSC1 — Oscillator input or RC external connection |
| Pin 13 | OSC2 — Oscillator output; CLKIN in RC mode |
| Pin 14 | T0CKI — Timer0 clock input (shared with I/O) |
| Pin 15 | MCLR — Master clear reset (active low) |
| Pin 16 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 17 | RA1 — Bidirectional I/O port A bit 1 |
| Pin 18 | VDD — Positive supply voltage (3.0 V to 6.25 V) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | NC — Not connected (per datasheet) |
Typical Applications
PIC16LC54AT-04/SS is suitable for 7 applications: Battery-Powered Sensor Transmitter, Simple Relay and Solenoid Controller, Remote Control Transmitter (RF/IR), Consumer Appliance Timer Controller, LED Display and Sign Driver, Replacement of Discrete Logic in Legacy Designs, Toy and Hobby Electronic Controller.
Battery-Powered Sensor Transmitter
The PIC16LC54AT-04/SS fits battery-powered sensor transmitters because its low-voltage CMOS core operates down to 3.0 V, drawing microamp-level standby current from 2-3 AA cells that can last years. The 4 MHz clock and 768 bytes of OTP program memory hold a simple wake-measure-transmit-sleep state machine, while 25 bytes of RAM buffer sensor readings. The 12-bit instruction set and fully static design let the firmware stop the clock entirely between transmissions, a feature unique to CMOS PIC16C5X parts and unavailable on older NMOS designs.
Recommended
Simple Relay and Solenoid Controller
For relay and solenoid switching panels, the PIC16LC54AT-04/SS provides 12 digital I/O pins, each capable of sourcing or sinking enough current to drive a transistor driver stage. Its deterministic instruction execution (no interrupts, fixed 1 us per instruction at 4 MHz) makes timing easy to calculate without race conditions. The OTP memory locks the relay-firing logic at production, preventing accidental firmware change in the field. The wide 3.0-6.25 V supply range accepts 5 V industrial rails directly.
Recommended
Remote Control Transmitter (RF/IR)
The PIC16LC54AT-04/SS is well-suited to handheld remote controls where cost dominates and firmware is finalized before volume production. Its 4 MHz CPU produces precise timing for IR carrier generation (typically 38 kHz) and RF Manchester/PCM encoding without needing a hardware UART. The 12 I/O pins drive the keypad matrix and TX modulator, while the low-voltage CMOS core extends battery life across years of standby. OTP memory locks the pairing code at the factory, blocking aftermarket cloning.
Recommended
Consumer Appliance Timer Controller
Microwave ovens, washing machines, and small kitchen appliances use the PIC16LC54AT-04/SS to sequence motor, heater, and buzzer events. The OTP memory locks the appliance firmware at factory build, removing any risk of post-sale tampering with safety timing. The watchdog timer with on-chip RC oscillator independently monitors software lockup, resetting the MCU if the main loop stalls. The 25 bytes of RAM are enough for countdown timers and mode flags without external memory expansion.
Recommended
LED Display and Sign Driver
For static LED signs, channel letters, and animated light bars, the PIC16LC54AT-04/SS sequences multiple LED rows and columns without external logic. Each of the 12 I/O pins can source or sink 25 mA directly when configured as output, enough for indicator LEDs and small 7-segment digits. The 4 MHz clock multiplexes 4-8 digit displays at refresh rates above 100 Hz, eliminating visible flicker. OTP locking prevents end users from altering the display pattern after deployment.
Recommended
Replacement of Discrete Logic in Legacy Designs
The PIC16LC54AT-04/SS replaces clusters of 74HC00-series logic gates in legacy designs by reading inputs and computing outputs entirely in firmware. A single PIC16LC54AT-04/SS can replace 4-8 discrete logic ICs, reducing PCB area and assembly cost. The OTP memory ensures the replacement logic is locked exactly to the legacy behavior. The 20-SSOP footprint occupies less board space than two SO-14 gates, simplifying the layout of older industrial control boards.
Recommended
Toy and Hobby Electronic Controller
The PIC16LC54AT-04/SS powers motor and sound sequencing in low-cost toys, model train controllers, and hobby electronics. Its 4 MHz CPU and 12-bit instructions generate servo PWM, beep tones, and motor H-bridge control patterns without external timers. OTP memory locks game-play logic to prevent firmware hacking in mass-market toys. The wide 3.0-6.25 V supply runs directly from 2-4 cell battery packs, eliminating the need for voltage regulation.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC54AT-04/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LC54A-04/SS | PIC16LC54A-04E/SS | PIC16F54T-I/SS | PIC16C54AT-04E/SS | PIC16C54AT-04I/SS |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-SSOP | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same | 20-SSOP - same |
| Program Memory Type | OTP (768 bytes) | OTP (768 bytes) | OTP (768 bytes) | Flash (768 bytes) | OTP (768 bytes) | OTP (768 bytes) |
| Maximum Clock | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 4 MHz | 4 MHz |
| Supply Voltage | 3.0 V to 6.25 V | 3.0 V to 6.25 V | 3.0 V to 6.25 V | 2.0 V to 5.5 V | 4.0 V to 6.25 V | 4.0 V to 6.25 V |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 12 |
| RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| Packaging Format | Tape & Reel (T suffix) | Tube | Tube | Tape & Reel | Tape & Reel | Tape & Reel |
Key Differentiators
- Lowest-cost 8-bit MCU option at 3.0 V operation (vs PIC16C54AT-04E/SS)
- OTP cost advantage over flash for high-volume production (vs PIC16F54T-I/SS)
- Tape-and-reel packaging for SMT assembly (vs PIC16LC54A-04/SS (tube))
Design Notes
OTP memory is write-once: any firmware bug forces a board re-spin. Always prototype with the PIC16F54T-I/SS flash equivalent (same SSOP-20 footprint and pinout), validate the firmware completely, then commit to PIC16LC54AT-04/SS only for the production BOM. Estimating: prototyping with PIC16F54T-I/SS adds roughly $0.30 per unit but avoids $5,000-$20,000 in respin costs if a firmware bug ships.
Add a 0.1 uF ceramic decoupling capacitor directly between VDD (pin 18) and VSS (pin 11), placed within 5 mm of the IC. For designs with noisy relay or solenoid coils nearby, add a 10 uF tantalum or aluminum bulk cap in parallel. The PIC16LC54AT-04/SS core draws less than 2 mA at 4 MHz / 5 V, but I/O pin switching transients can inject supply noise without proper bypassing.
Place the oscillator crystal or resonator within 10 mm of pins 12-13 (OSC1/OSC2), with a ground guard ring around the oscillator traces to block switching noise coupling into the clock. Keep the MCLR pull-up (typically 10 kohm to VDD) close to pin 15. The SSOP-20 footprint has a 0.65 mm pitch - use 0.15 mm/6 mil trace-and-space rules for escape routing and a 0.30 mm solder mask dam between pads to prevent solder bridging during reflow.
The PIC16LC54AT-04/SS has no internal interrupt controller - all timing is handled by polled loops and the watchdog timer. Software structure must poll the watchdog (CLRWDT instruction) at least every 18 ms (typical WDT period) or the chip will reset. Estimating: at 4 MHz each instruction takes 1 us, so place CLRWDT calls no more than 18,000 instructions apart in the main loop.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified; for automotive applications consult Microchip for PIC16F or PIC18 family AEC-Q100 parts.
