PIC16C558-20I/P - 20MHz 8-bit OTP MCU, 3.5KB EPROM, 18-PDIP | Microchip
MPN: PIC16C558-20I/P ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.22 | $4.22 |
| 10 | $3.85 | $38.50 |
| 100 | $3.42 | $342.00 |
| 500 | $3.1 | $1,550.00 |
| 1,000 | $2.78 | $2,780.00 |
PIC16C558-20I/P Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, working RAM, and peripheral I/O on one die. The PIC16C558 belongs to the mid-range PIC microcontrollers category, which sits inside the broader 8-bit MCU taxonomy (8-bit MCU -> microcontroller -> embedded processor -> semiconductor). Mid-range PIC parts extend baseline PIC12/PIC14 devices with more interrupts, larger memory, and a richer peripheral set, while remaining cheaper and simpler than 16-bit dsPIC or 32-bit PIC32 parts.
Key features include 200 ns instruction execution at 20 MHz, 14-bit instruction width, two 8-bit timers (Timer0, Timer2) plus a 16-bit Timer1, a 10-bit (approximate) capture/compare/PWM module, 8-bit parallel port architecture, and a programmable watchdog timer with on-chip RC oscillator. Power-saving features include SLEEP mode with wake-up on pin change, and the device supports in-circuit serial programming (ICSP) despite the OTP program memory, allowing prototype code drop-in to OTP shipping units.
The architecture is a Harvard RISC design with separate program (14-bit) and data (8-bit) buses, eliminating fetch bottlenecks and giving deterministic single-cycle execution for most instructions. The OTP memory cell uses a one-time-fuse bit per instruction word, providing non-volatile storage after programming. Brown-out reset (BOR), power-on reset (POR), and a configurable oscillator selection (LP, XT, HS, RC) make the part tolerant of noisy industrial supplies and a wide range of crystal frequencies.
Typical applications include appliance control boards, automotive body electronics subsystems, industrial sensor interfaces, simple closed-loop fan or pump controllers, and low-cost user-interface panels where the PIC16C558-20I/P can replace larger 40-pin MCUs. The 18-pin PDIP footprint remains popular in through-hole manufacturing lines and in legacy designs that need a stable, long-lifecycle controller.
When designing with this device, allocate one full 5 V-tolerant port for the ICSP interface even in production units, because OTP parts still require ICSP for the initial code load. Decouple VDD/VSS with a 100 nF ceramic placed within 5 mm of the pins, and configure the MCLR pin with the standard 10 kΩ pull-up plus a 100 nF reset-delay capacitor to ensure clean power-on behavior.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, organized for both procurement and engineering audiences.
Drop-in alternatives for PIC16C558-20I/P — 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 PIC16C558-20I/P (same form factor and footprint) — differing in Package, Timers, Program Memory Type, Watchdog Timer, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C558-20/P
✅ Drop-In✓ In Stock
$1.72 / Unit
View Datasheet →PIC16C558-20/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C558-20/SO
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C558-04I/SO
✅ Drop-In✓ In Stock
$3.11 / Unit
View Datasheet →PIC16C558-20E/SS
✅ Drop-In✓ In Stock
$2.53 / Unit
View Datasheet →PIC16C558-20I/P Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Series | PIC16C |
| Architecture | PIC16 (Mid-Range Harvard RISC) |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Program Memory Size | 3.5 KB (2K x 14 words) |
| RAM Size | 128 bytes |
| Number of I/O Pins | 13 |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Instruction Set Size | 35 single-word instructions |
| Supply Voltage | 3.3 V / 5 V (3.0 V to 5.5 V operating range) |
| Operating Temperature | -40 °C to +85 °C (Industrial, /I suffix) |
| Package | 18-pin PDIP (0.300 in / 7.62 mm) |
| Mounting Type | Through Hole |
| Timers | Timer0 (8-bit), Timer1 (16-bit), Timer2 (8-bit) |
| CCP Module | Capture/Compare/PWM (1 channel) |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| Brown-out Reset / POR | Yes |
| ICSP (In-Circuit Serial Programming) | Supported |
PIC16C558-20I/P Pin Configuration
| Pin 1 | RA2 — PORTA bit 2 (bidirectional digital I/O) |
| Pin 2 | RA3 — PORTA bit 3 (bidirectional digital I/O) |
| Pin 3 | RA4 — PORTA bit 4 (bidirectional digital I/O, also Timer0 clock input) |
| Pin 4 | MCLR — Master Clear (reset) input, active low |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — PORTB bit 0 (bidirectional digital I/O, external interrupt) |
| Pin 7 | RB1 — PORTB bit 1 (bidirectional digital I/O) |
| Pin 8 | RB2 — PORTB bit 2 (bidirectional digital I/O) |
| Pin 9 | RB3 — PORTB bit 3 (bidirectional digital I/O) |
| Pin 10 | RB4 — PORTB bit 4 (bidirectional digital I/O, interrupt-on-change) |
| Pin 11 | RB5 — PORTB bit 5 (bidirectional digital I/O, interrupt-on-change) |
| Pin 12 | RB6 — PORTB bit 6 (bidirectional digital I/O, interrupt-on-change, ICSP clock) |
| Pin 13 | RB7 — PORTB bit 7 (bidirectional digital I/O, interrupt-on-change, ICSP data) |
| Pin 14 | VDD — Positive supply voltage (3.0 V to 5.5 V) |
| Pin 15 | OSC2 — Oscillator output (crystal/ceramic resonator connection) |
| Pin 16 | OSC1 — Oscillator input (crystal/ceramic resonator or external clock) |
| Pin 17 | RA0 — PORTA bit 0 (bidirectional digital I/O) |
| Pin 18 | RA1 — PORTA bit 1 (bidirectional digital I/O) |
Typical Applications
PIC16C558-20I/P is suitable for 6 applications: Appliance Control Boards, Automotive Body Electronics Subsystems, Industrial Sensor Interface Modules, Small Fan or Pump Speed Controllers, User-Interface Panel Controllers, Legacy Through-Hole Industrial Controls.
Appliance Control Boards
The PIC16C558-20I/P is a strong fit for white-goods and small-appliance controller boards where its 20 MHz throughput, 13 GPIO pins, and OTP cost advantage deliver the lowest BOM cost. With 3.5 KB of program memory it can host motor-control state machines plus user-interface scanning for washing-machine, dishwasher, and microwave front panels. The /I industrial temperature grade covers the under-cabinet thermal environment of most kitchen installations.
Recommended
Automotive Body Electronics Subsystems
The PIC16C558-20I/P is suited to non-safety automotive body-electronics subsystems such as seat controllers, mirror adjusters, and simple lighting drivers, where its -40 °C to +85 °C industrial temperature grade and proven PIC16 reliability are acceptable. With three timers (8-bit, 16-bit, 8-bit) and a single CCP channel it can drive a small brushed DC motor for mirror-fold or window-lift sub-functions. For safety-critical or AEC-Q100-mandated subsystems, migrate to a Q100-qualified flash-based PIC16F or dsPIC33 part instead.
Recommended
Industrial Sensor Interface Modules
The PIC16C558-20I/P fits low-channel-count industrial sensor-interface modules that aggregate digital inputs and drive relay or opto-isolated outputs. Its 13 GPIO pins can scan up to 13 dry-contact sensor inputs, with the 16-bit Timer1 providing precise interval timing for debounce and event timestamping. The brown-out reset and watchdog timer protect against the supply transients common on 24 V industrial bus rails feeding downstream regulators.
Recommended
Small Fan or Pump Speed Controllers
The PIC16C558-20I/P works well as the brain in low-power single-phase fan or pump speed controllers, where its single CCP module generates PWM at 20 MHz with sufficient resolution for 4-quadrant closed-loop control. The 16-bit Timer1 can be configured as a counter for tachometer feedback from a Hall sensor. OTP memory locks the calibrated control law at production time, preventing firmware drift across the unit's installed lifetime.
Recommended
User-Interface Panel Controllers
The PIC16C558-20I/P drives low-cost membrane-key and LED-indicator user-interface panels for exercise equipment, vending machines, and HVAC thermostats. Its 13 GPIO pins scan a 4×4 matrix keypad with 8 remaining lines driving LED or 7-segment indicators via the CCP PWM channel for dimming. The PIC16 RISC core's deterministic interrupt latency keeps button-press response snappy and consistent across all temperature corners.
Recommended
Legacy Through-Hole Industrial Controls
The PIC16C558-20I/P is the correct replacement for maintaining legacy through-hole industrial control boards that were originally designed around the PIC16C55x 18-pin PDIP footprint. Its through-hole 18-pin PDIP remains the easiest package for hand-rework and field replacement on older equipment that still populates axial and through-hole components. The OTP memory matches the original part's locked firmware behavior, avoiding unintended configuration drift during repair.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C558-20I/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C558-20/P | PIC16C558-20/SS | PIC16C558-04I/SO |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-pin PDIP | 18-pin PDIP - same | 20-pin SSOP - same die, surface-mount | 18-pin SOIC - same die, surface-mount |
| Maximum Clock Frequency | 20 MHz | 20 MHz - same | 20 MHz - same | 4 MHz - lower |
| Program Memory | 3.5 KB OTP EPROM | 3.5 KB OTP EPROM - same | 3.5 KB OTP EPROM - same | 3.5 KB OTP EPROM - same |
| Operating Temperature Grade | Industrial (-40C to +85C) | Commercial (0C to +70C) | Industrial (-40C to +85C) - same | Industrial (-40C to +85C) - same |
| RAM Size | 128 bytes | 128 bytes - same | 128 bytes - same | 128 bytes - same |
| I/O Pins | 13 | 13 - same | 13 - same | 13 - same |
| Mounting Type | Through Hole | Through Hole - same | Surface Mount - different | Surface Mount - different |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Industrial temperature grade on through-hole footprint (vs PIC16C558-20/P)
- Through-hole PDIP vs surface-mount SSOP/SOIC (vs PIC16C558-20/SS)
- 20 MHz full speed vs 4 MHz cost-down grade (vs PIC16C558-04I/SO)
Design Notes
Decouple VDD (pin 14) and VSS (pin 5) with a 100 nF ceramic capacitor placed within 5 mm of the pins. For boards exposed to industrial supply noise, add a 10 µF bulk tantalum or aluminum polymer capacitor on the same rail as the MCU. The PIC16C558-20I/P operates from 3.0 V to 5.5 V; voltages below 3.0 V may cause brown-out reset to trigger intermittently, especially when the ICSP module is active.
Place the 20 MHz crystal or resonator within 5 mm of OSC1 (pin 16) and OSC2 (pin 15), with short, symmetric traces and a ground guard ring to reduce EMI radiation. Add 22-33 pF load capacitors matching the crystal's load capacitance specification. Keep high-current traces (motor drivers, relay coils) at least 10 mm away from the oscillator network to prevent clock jitter and missed interrupts.
Do not assume OTP parts cannot be programmed: the PIC16C558-20I/P supports ICSP on RB6 (ICSP clock) and RB7 (ICSP data), and an external programmer must still be able to drive these pins in production. Reserve these pins for ICSP even on shipping units, or provide test-point access, otherwise factory firmware loading becomes impossible. Also configure MCLR (pin 4) with a 10 kΩ pull-up to VDD plus a 100 nF reset-delay capacitor to ensure clean power-on reset behavior.
Estimated: at 20 MHz clock with all peripherals enabled and GPIO sourcing 20 mA per pin, the PIC16C558-20I/P dissipates approximately 250 mW worst case from a 5 V supply. Junction-to-ambient thermal resistance of a PDIP-18 package is around 70 °C/W, giving a temperature rise of approximately 17 °C above ambient. No heatsink is required for industrial-temperature operation, but verify with a thermal probe in an enclosed chassis before final qualification.
Compliance Information
Compliance status not confirmed in the provided distributor data; PIC16C558 family pre-dates Microchip's standardized RoHS/REACH reporting. Part is classified obsolete; verify compliance with the authorized distributor before procurement for regulated markets.
