PIC16LC558-04I/SO - 4MHz 8-bit MCU 3.5KB OTP 18-SOIC | Microchip
MPN: PIC16LC558-04I/SO β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.71 | $1.71 |
| 10 | $1.62 | $16.20 |
| 100 | $1.43 | $143.00 |
| 500 | $1.27 | $635.00 |
| 1,000 | $1.1 | $1,100.00 |
PIC16LC558-04I/SO Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, RAM, program memory, and peripherals. PIC microcontrollers use a modified Harvard RISC architecture with a small instruction set (33 single-word instructions in the PIC16C5x family), enabling predictable timing and efficient code density. PIC16C5x devices sit in the baseline hierarchy: 8-bit MCU -> RISC MCU -> PIC microcontroller -> embedded controller. The 'C' suffix designates the EPROM/OTP program memory variant (vs. 'F' for Flash), and the 'LC' prefix designates the low-voltage (2.5 V to 5.5 V) CMOS process node.
Key features include a 4 MHz maximum operating frequency, 2 K x 14 (3.5 KB) of OTP program memory organized as 12-bit-wide instructions, 128 bytes of data RAM, a 13-bit program counter addressing 8 KB of program space, and 13 digital I/O pins arranged across two ports (RA0-RA3, RA4, RB0-RB7). The device supports in-circuit serial programming (ICSP), has a watchdog timer, and operates from a single 2.5 V to 5.5 V supply. Its baseline architecture omits interrupts, simplifying deterministic loop-based firmware patterns.
The PIC16LC558 uses a RISC pipelined execution engine with 12-bit instructions and a fixed instruction cycle of 4 oscillator clocks (1 Β΅s per instruction at 4 MHz). The Harvard bus architecture separates program and data memory buses, allowing simultaneous instruction fetch and data access. The OTP memory is windowless and one-time-programmable - once programmed the code is permanent but cannot be erased, making the part well suited to mature production firmware with no field upgrade requirement.
Typical applications include appliance control, sensor interfaces, low-end consumer electronics, industrial control logic, automotive body modules (non-safety), LED drivers, and battery-powered devices where 2.5 V operation from a single cell plus a boost converter extends usable runtime. The 13 I/O and small memory suit simple state-machine and fixed-sequence control tasks.
When designing with the PIC16LC558-04I/SO, note that it lacks interrupts and on-chip peripherals beyond timers and watchdog, so firmware must use polling. The OTP memory means firmware must be finalized before programming - there is no Flash-style in-field update path. Designers targeting the same pinout with flash memory should evaluate the PIC16F505 / PIC16F506 families in SOIC packages.
This page synthesizes distributor pricing, parametric alternatives, and design notes for the PIC16LC558-04I/SO that are not consolidated in the Microchip datasheet alone.
Drop-in alternatives for PIC16LC558-04I/SO 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 PIC16LC558-04I/SO (same form factor and footprint) β differing in Package, Timers, Program Memory Size, Watchdog Timer, Program Memory Type.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C558-04I/SO
β Drop-Inβ In Stock
$3.11 / Unit
View Datasheet βPIC16LC558-04/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C558-04/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16F505-04I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16F506-I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16LC558-04I/SO Maximum Ratings & Electrical Characteristics
| Core | PIC 8-bit RISC |
| Family | PIC16C5x (PIC16LC558) |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 3.5 KB (2K x 14) |
| Data RAM | 128 bytes |
| Maximum CPU Frequency | 4 MHz |
| Instruction Cycle | 1 us at 4 MHz (4 oscillator clocks per instruction) |
| Operating Voltage (Vdd) | 2.5 V to 5.5 V |
| I/O Pins | 13 |
| Number of Pins | 18 |
| Package | 18-SOIC (0.295 inch, 7.50 mm width) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 C to +85 C (Industrial, 'I' suffix) |
| Timers | Yes (8-bit RTCC + WDT) |
| Watchdog Timer | Yes |
| In-Circuit Serial Programming (ICSP) | Yes |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC16LC558-04I/SO 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 | RA4/T0CKI β Bidirectional I/O port A bit 4 / Timer 0 clock input |
| Pin 4 | MCLR/Vpp β Master clear reset input (active low) / programming voltage input |
| Pin 5 | Vss β Ground reference |
| Pin 6 | RB0/INT 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 | Vdd β Positive supply voltage (2.5 V to 5.5 V) |
| Pin 15 | OSC2/CLKOUT β Oscillator crystal output / clock output |
| Pin 16 | OSC1/CLKIN β Oscillator crystal input / external clock input |
| Pin 17 | RA0 β Bidirectional I/O port A bit 0 |
| Pin 18 | RA1 β Bidirectional I/O port A bit 1 |
Typical Applications
PIC16LC558-04I/SO is suitable for 6 applications: Appliance Control (Microwave, Washer, Dishwasher), Sensor Interface and Signal Conditioning, Battery-Powered Consumer Electronics, Industrial Control Logic (PLCs, Relay Drivers), LED Lighting and Display Drivers, Automotive Body Control Modules (Non-Safety).
Appliance Control (Microwave, Washer, Dishwasher)
The PIC16LC558-04I/SO is widely deployed in white-goods control boards (microwave ovens, washing machines, dishwashers) where its 3.5 KB OTP, 4 MHz CPU, and 13 I/O are sized for relay sequencing, LED indicators, and keypad scanning. The 2.5 V to 5.5 V Vdd lets the board share the appliance's existing 5 V or 3.3 V rail, and the 18-SOIC package sits flat against the PCB with no socket requirement. The OTP memory locks in the final firmware image at production, eliminating the risk of accidental field reprogramming that could change safety-relevant behavior.
Recommended
Sensor Interface and Signal Conditioning
In low-cost sensor-interface boards (temperature, humidity, PIR motion), the PIC16LC558-04I/SO reads analog signals through an external ADC, applies digital filtering in firmware, and drives a relay or UART output. Its 128-byte RAM is sufficient for 8 to 16 sample moving-average filters on 10 Hz signals, and the 4 MHz CPU executes the inner loop in well under 1 ms per cycle. The industrial -40 C to +85 C temperature range enables deployment in unheated outdoor enclosures, and the low 2.5 V Vdd supports battery-powered wireless sensor nodes.
Recommended
Battery-Powered Consumer Electronics
Battery-powered handheld devices (remote controls, electronic toys, kitchen scales) benefit from the PIC16LC558-04I/SO's 2.5 V to 5.5 V operating range, which allows direct connection to 2x AA alkaline cells (3.0 V) without a boost regulator. The 4 MHz speed handles button-debouncing, LCD driving, and simple PWM motor control, while 13 I/O is enough for keypads up to 4 x 4. The 18-SOIC surface-mount package is well suited to high-volume pick-and-place assembly, and the OTP memory prevents end users from cloning firmware via ISP access.
Recommended
Industrial Control Logic (PLCs, Relay Drivers)
In industrial logic modules, the PIC16LC558-04I/SO acts as a small I/O controller scanning discrete inputs and energizing relay coils or solid-state outputs. The 13 GPIO can be split into 8 inputs (PORTB) and 5 outputs (PORTA) for typical 8-input / 5-output logic modules, with firmware executing a deterministic ladder-logic simulation each 10 ms. The industrial -40 C to +85 C rating covers factory-floor environments, and the OTP memory prevents tampering with safety-relevant logic in the field.
Recommended
LED Lighting and Display Drivers
LED controllers for decorative lighting, signage, and 7-segment displays use the PIC16LC558-04I/SO to generate PWM dimming waveforms and multiplex display digits. At 4 MHz, each PWM period is set by a 256-step software counter, giving 16 kHz PWM at 60 Hz refresh with 8-bit dimming resolution. The 13 GPIO can drive up to 8 LED channels directly, and external transistors extend the drive to higher-current LED strings. The OTP memory locks the dimming curve and safety limits at production time.
Recommended
Automotive Body Control Modules (Non-Safety)
In non-safety automotive body modules (window lift logic, mirror control, ambient lighting), the PIC16LC558-04I/SO scans switches, drives small motors, and communicates via LIN or simple PWM. The industrial -40 C to +85 C temperature grade covers cabin environments (under-hood modules need -40 C to +125 C, requiring PIC16F or PIC18F parts). The 4 MHz CPU and 3.5 KB OTP are sufficient for state-machine control of 2 to 4 motors with debounced switch inputs.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC558-04I/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C558-04I/SO | PIC16LC558-04/SO | PIC16C558-04/SO | PIC16F505-04I/SO | PIC16F506-I/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Program Memory | 3.5 KB OTP | 3.5 KB OTP | 3.5 KB OTP | 3.5 KB OTP | 1.5 KB Flash | 1.5 KB Flash |
| RAM | 128 bytes | 128 bytes | 128 bytes | 128 bytes | 72 bytes | 67 bytes |
| Max CPU Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| Supply Voltage | 2.5 V to 5.5 V | 3.0 V to 6.0 V | 2.5 V to 5.5 V | 3.0 V to 6.0 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V |
| I/O Pins | 13 | 13 | 13 | 13 | 12 | 12 |
| Temperature Range | -40 C to +85 C (Industrial) | -40 C to +85 C | 0 C to +70 C | 0 C to +70 C | -40 C to +85 C | -40 C to +85 C |
| Memory Type | OTP | OTP | OTP | OTP | Flash (reprogrammable) | Flash (reprogrammable) |
Key Differentiators
- Same 18-SOIC footprint with Flash reprogrammability for field-updateable firmware (vs PIC16C558-04I/SO (OTP))
- 5x faster CPU clock for time-critical or PWM-intensive applications (vs PIC16F505-04I/SO (4 MHz))
- Adds 10-bit ADC for direct analog sensor reading (vs PIC16LC558-04I/SO (no ADC))
- Lower voltage operation enables direct 2x alkaline cell operation (vs PIC16C558-04I/SO (3.0V min))
Design Notes
The PIC16LC558-04I/SO is a baseline PIC16C5x device with NO interrupt controller - all firmware must be implemented as polled state machines. Do not attempt to write interrupt-driven code; the device lacks the INTCON, PIE, and PIR registers entirely. Also note that the OTP memory can be programmed only ONCE; if the firmware needs field updates, choose the PIC16F505 or PIC16F506 family instead. The baseline architecture also lacks a hardware UART, so asynchronous serial must be bit-banged in firmware.
Estimated: at 4 MHz CPU clock and 5.0 V Vdd, active current is approximately 2 mA typical and 5 mA maximum. The PIC16LC558 has no true sleep mode (baseline architecture) - the lowest power state is the Watchdog Timer (WDT) wakeup from halt, with the CPU clock stopped. If the application requires idle currents below 100 uA, use the PIC16F505 (Flash, has SLEEP instruction) or PIC16LF1554 instead. Add a 100 nF decoupling capacitor as close as possible to the Vdd pin (pin 14).
Place a 100 nF ceramic decoupling capacitor within 5 mm of the Vdd pin (14) with the ground trace returning directly to the Vss pin (5) - this minimizes switching-noise-induced brownouts during oscillator transitions. For the MCLR pin (4), a 10 kohm pull-up to Vdd plus a 100 nF cap to ground implements the standard Microchip recommended reset circuit. If using a crystal oscillator, keep the crystal traces short (under 10 mm) and surround them with a ground pour to reduce EMI.
When designing the PCB, use a 4-layer stack-up with a dedicated ground plane for the SOIC18 footprint to keep digital switching noise away from analog references. The 18-SOIC land pattern follows JEDEC MS-013 with 1.27 mm pin pitch - copy the pattern directly from the Microchip land pattern document rather than scaling a generic SOIC footprint. For production programming, expose the ICSP pins (RB6/ RB7 / MCLR) to test points or a header to enable in-circuit serial programming during board bring-up.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - this part is intended for industrial / consumer use, not automotive safety-critical applications.