PIC16C558-20/SS - 3.5KB OTP 8-bit MCU, 20 SSOP | Microchip
MPN: PIC16C558-20/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3 | $3.00 |
| 10 | $2.8 | $28.00 |
| 100 | $2.55 | $255.00 |
| 500 | $2.3 | $1,150.00 |
| 1,000 | $2.05 | $2,050.00 |
PIC16C558-20/SS Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program memory, working RAM, and peripheral interfaces. The PIC16C558 belongs to the PIC16C5X family of OTP (one-time-programmable) baseline-to-mid-range controllers, sitting in the system hierarchy as follows: PIC16C5X → PIC16C family → 8-bit PIC microcontroller → embedded MCU → semiconductor. The OTP memory is factory- or field-programmed once using a device programmer and cannot be erased, making the PIC16C558 suited to high-volume fixed-code applications rather than firmware development.
Key features include 13 bidirectional I/O pins with individual direction control, an 8-bit timer/counter (TMR0) with an 8-bit prescaler, a watchdog timer with on-chip RC oscillator for reliable system recovery, and power-saving SLEEP mode. The device also integrates a 4 MHz internal RC oscillator option (selected at programming time), a programmable code-protection scheme, and an in-circuit serial programming (ICSP) interface that allows programming after PCB assembly.
The PIC16C558 uses a RISC Harvard architecture with separate program and data buses, allowing instruction fetch and data access to occur in parallel. The 8-bit ALU, 8-bit working register (W), 11-bit program counter, and 2-level deep hardware stack provide deterministic execution suitable for interrupt-free control loops. The 20 MHz clock with 4-clock-per-instruction cycle produces the headline 200 ns instruction time referenced in the device family literature.
Typical applications include appliance controls, automotive body electronics (with the -I and -E temperature variants), industrial sensor interfaces, LED drivers, and low-cost remote-control transmitters. The wide 3.0-5.5 V supply range supports both 3.3 V and 5 V system designs. Engineers designing with the PIC16C558 should plan for OTP programming early in the design cycle, since the device cannot be re-programmed in-circuit beyond the initial ICSP write; for iterative development a FLASH-based PIC16F equivalent is recommended, but only certain speed-grade and pinout variants qualify as true drop-in parts. This page synthesizes distributor pricing, drop-in same-package alternatives drawn from the verified cross-reference data, and practical design notes not aggregated on any single manufacturer or distributor page.
Drop-in alternatives for PIC16C558-20/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 PIC16C558-20/SS (same form factor and footprint) — differing in Package, Program Memory Size, Program Memory Type, Timers, Watchdog Timer.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C558T-20/SS
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →PIC16C558-04/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C554T-20/SS
✅ Drop-In✓ In Stock
$1.74 / Unit
View Datasheet →PIC16C554T-04I/SS
✅ Drop-In✓ In Stock
$1.09 / Unit
View Datasheet →PIC16C55-10I/SS
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC12F675-I/P
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C558-20/SS Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Program Memory Type | OTP (One-Time-Programmable) EPROM |
| Program Memory Size | 3.5 KB (2048 x 14-bit words) |
| Data RAM | 128 bytes |
| Number of I/O Pins | 13 |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Instruction Set | 35 single-word instructions (PIC mid-range) |
| Supply Voltage (Vdd) | 3.0 V to 5.5 V |
| Operating Temperature | 0 °C to +70 °C (commercial) |
| Package | 20-pin SSOP (SS, 5.30 mm body, 0.65 mm pitch) |
| Mounting Type | Surface Mount |
| Timers | 1 x 8-bit Timer (TMR0) with 8-bit prescaler |
| Watchdog Timer | Yes, with on-chip RC oscillator |
| Oscillator Modes | External RC, External Crystal/Ceramic, Internal 4 MHz RC (selected at programming) |
| Code Protection | Programmable via EPROM fuse bits |
| In-Circuit Programming | ICSP supported |
| Architecture | RISC, Harvard (separate program/data buses) |
| Hardware Stack | 2 levels |
| RoHS Status | Compliant |
PIC16C558-20/SS Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O pin; also analog input on some PIC16C5X variants |
| Pin 2 | RA3 — Bidirectional I/O pin |
| Pin 3 | T0CKI — Timer0 external clock input |
| Pin 4 | !MCLR/VPP — Master Clear reset input (active-low) / programming voltage input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Bidirectional I/O pin; also external interrupt input |
| Pin 7 | RB1 — Bidirectional I/O pin |
| Pin 8 | RB2 — Bidirectional I/O pin |
| Pin 9 | RB3 — Bidirectional I/O pin |
| Pin 10 | RB4 — Bidirectional I/O pin |
| Pin 11 | RB5 — Bidirectional I/O pin |
| Pin 12 | RB6 — Bidirectional I/O pin |
| Pin 13 | RB7 — Bidirectional I/O pin |
| Pin 14 | VSS — Ground reference |
| Pin 15 | VDD — Positive supply (3.0 V to 5.5 V) |
| Pin 16 | RC0 — Bidirectional I/O pin |
| Pin 17 | RC1 — Bidirectional I/O pin |
| Pin 18 | RC2 — Bidirectional I/O pin |
| Pin 19 | RC3 — Bidirectional I/O pin |
| Pin 20 | OSC1/CLKIN — Oscillator crystal input or external clock input |
Typical Applications
PIC16C558-20/SS is suitable for 8 applications: Appliance Control Panels, Automotive Body Electronics, Industrial Sensor Interfaces, Remote Control Transmitters, LED Lighting Drivers, Battery Charger Controllers, Toy and Hobby Electronics, Smart Home Sensor Nodes.
Appliance Control Panels
The PIC16C558-20/SS fits appliance control panels (washer, dryer, dishwasher, microwave user interfaces) because its 13 digital I/O pins are sufficient to scan a 4x4 keypad matrix and drive 7-segment or LCD indicator outputs, while the 3.5 KB OTP memory holds fixed menu and timing code. Its 3.0-5.5 V supply range interfaces directly to 5 V logic and to white-LED indicator drivers. Unlike FLASH MCUs, the OTP memory prevents field firmware tampering, a regulatory advantage for safety-certified appliances. The SSOP-20 footprint allows compact PCB integration behind the front panel.
Recommended
Automotive Body Electronics
The PIC16C558-20/SS, in its -I industrial temperature variant, is used in non-safety automotive body modules such as interior lighting controllers, mirror adjusters, and seat-position sensors. The 20 MHz instruction rate handles LIN-bus bit-banging at 19.2 kbaud and PWM-driven LED dimming in firmware without external peripherals. The 13 I/O pins drive multiple MOSFET half-bridges and read Hall-effect or potentiometer feedback. The OTP memory prevents end-user reflashing of calibration constants, supporting OEM service procedures. A watch-dog timer with internal RC oscillator provides the deterministic reset behavior required by ISO 7637 transient tests when properly characterized.
Recommended
Industrial Sensor Interfaces
The PIC16C558-20/SS is well-suited to industrial 4-20 mA loop-powered sensor transmitters and simple PLC input modules where its 3.0-5.5 V supply matches 24 V-to-5 V regulator rails and its 20 MHz instruction cycle handles digital filtering of pulse-train sensor outputs. The 128 B RAM buffers ASCII command strings from RS-485 slaves using bit-banged UART, and the 3.5 KB OTP memory holds calibration tables and Modbus protocol stacks. The watchdog timer with internal RC oscillator meets the IEC 61131-2 requirement for deterministic recovery from firmware upset. Industrial users should select the -I or -E temperature grade for operation across -40 °C to +125 °C.
Recommended
Remote Control Transmitters
The PIC16C558-20/SS powers 315/433/868 MHz ISM-band remote-control transmitters (garage-door openers, ceiling-fan controllers, RF keyfobs) where its 20 MHz instruction cycle generates precise PWM timing for OOK/ASK modulation and its 13 I/O pins scan 4x4 keypad matrices. The OTP memory holds fixed transmitter ID codes that cannot be erased by an attacker, a security benefit over FLASH parts. Low-cost SLEEP mode with watchdog wake-up extends battery life in intermittent-keypress applications to multi-year lifetimes on a single coin cell. The SSOP-20 footprint fits inside the smallest keyfob housings.
Recommended
LED Lighting Drivers
The PIC16C558-20/SS controls decorative and architectural LED drivers (RGB strips, DMX512 slaves, low-power architectural fixtures) where its 20 MHz instruction cycle produces DMX-512 break and mark-after-break timing in firmware without an external UART, and its 13 I/O pins drive three PWM channels plus a chip-select/address bus for cascaded drivers. The 128 B RAM holds DMX slot data and the 3.5 KB OTP memory stores personality profiles and color macros that cannot be field-modified, ensuring consistent show programming across venues. Watch-dog reset recovers from mains brown-out events common in stage-power environments.
Recommended
Battery Charger Controllers
The PIC16C558-20/SS is used in NiCd/NiMH and small Li-ion charger controllers where its 13 I/O pins monitor cell voltage, current shunt, and temperature thermistor while driving MOSFET half-bridges for charge/discharge control. The 200 ns instruction cycle samples the ADC-equivalent voltage at > 10 kHz to implement constant-current, constant-voltage (CCCV) charge termination algorithms. The watchdog timer protects against firmware lockup during fault conditions, and the 3.0-5.5 V supply operates directly from a single Li-ion cell. OTP memory prevents unauthorized firmware changes that could compromise charge-safety profiles.
Recommended
Toy and Hobby Electronics
The PIC16C558-20/SS drives hobby-grade RC receivers, animated toys, model-train controllers, and educational kits where its 20 MHz instruction cycle executes simultaneous servo PWM generation and IR-protocol decoding without peripheral contention. The 13 I/O pins handle up to 4 hobby servos plus an IR receiver input and a serial debug link. OTP memory locks the toy firmware so end users cannot accidentally reflash a safety-relevant motor control. The SSOP-20 package is small enough for hand-held enclosures and the 3.0-5.5 V supply runs from 2x AA cells with a boost converter.
Recommended
Smart Home Sensor Nodes
The PIC16C558-20/SS implements simple smart-home sensor endpoints (door/window contacts, PIR motion detectors, temperature/humidity loggers) where its 13 I/O pins connect to a PIR sensor, a digital temperature IC, and a sub-GHz or BLE module via UART. The watchdog timer with internal RC oscillator provides deterministic recovery from RF-induced firmware upsets, and SLEEP mode with < 1 µA quiescent extends battery life to multi-year operation on a CR2032 cell. The 3.5 KB OTP memory holds the application code plus a small ZigBee or proprietary stack fragment. The SSOP-20 package is small enough for in-wall mounting boxes.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C558-20/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C558T-20/SS | PIC16C558-04/SS | PIC16C554T-20/SS | PIC16C554T-04I/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SSOP-20 | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same |
| Program Memory | 3.5 KB OTP | 3.5 KB OTP - same | 3.5 KB OTP - same | 0.875 KB OTP - 75% less | 0.875 KB OTP - 75% less |
| RAM | 128 B | 128 B - same | 128 B - same | 80 B - 38% less | 80 B - 38% less |
| Max Clock Frequency | 20 MHz | 20 MHz - same | 4 MHz - 80% less | 20 MHz - same | 4 MHz - 80% less |
| Instruction Cycle | 200 ns | 200 ns - same | 1000 ns - 5x slower | 200 ns - same | 1000 ns - 5x slower |
| I/O Pins | 13 | 13 - same | 13 - same | 13 - same | 13 - same |
| Supply Voltage | 3.0 V to 5.5 V | 3.0 V to 5.5 V - same | 3.0 V to 5.5 V - same | 3.0 V to 5.5 V - same | 3.0 V to 5.5 V - same |
| Operating Temperature | 0 °C to +70 °C (Commercial) | 0 °C to +70 °C - same | 0 °C to +70 °C - same | 0 °C to +70 °C - same | -40 °C to +85 °C (Industrial) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Highest program memory in the PIC16C5X SSOP-20 line (vs PIC16C554T-20/SS)
- Maximum throughput of 20 MHz in the family (vs PIC16C558-04/SS)
- Standard commercial 0 °C to +70 °C temperature grade (vs PIC16C554T-04I/SS)
- Largest RAM in the PIC16C5X SSOP-20 tier (vs PIC16C55-10I/SS)
Design Notes
The PIC16C558-20/SS draws a typical operating current of 1.8 mA at 5 V and 4 MHz, scaling to roughly 7 mA at 20 MHz with all I/O pins switching; SLEEP mode current is < 1 µA. Place a 100 nF decoupling capacitor within 5 mm of the VDD pin and a 10 µF bulk capacitor near the IC supply entry to suppress switching transients during SLEEP-to-active wake events. Estimated: the 7 mA figure at 20 MHz is an extrapolation based on the 1.8 mA / 4 MHz datasheet typical and assumes CMOS I/O loading; verify with bench measurement on the final PCB layout.
Choose the oscillator mode (external RC, external crystal, or internal 4 MHz RC) by programming the FOSC configuration fuse at OTP-programming time — the selection is non-reversible after programming. For UART bit-banging at standard baud rates above 19.2 kbaud, use a crystal or ceramic resonator with a stability of ±100 ppm or better; the internal 4 MHz RC oscillator is typically ±5% and is unsuitable for asynchronous serial without software over-sampling. When migrating to the -04 speed grade, retune any bit-banged timing loops to the 1 µs instruction cycle before deployment.
The OTP memory is one-time-programmable — a bad configuration fuse write (wrong oscillator mode, accidental code-protect enable, wrong watchdog timer selection) cannot be undone. Always program engineering samples first, validate the configuration with a socketed test, and only then proceed to volume programming. Distinguish between PIC16C558 (3.5 KB, 128 B RAM) and the smaller PIC16C554 (0.875 KB, 80 B RAM) — the device ID word read at programming time is the only reliable check, since both share the same SSOP-20 footprint. Always order pre-programmed parts from the factory (CSW - Custom Standard Order) rather than attempting field OTP programming for production volumes.
The PIC16C558-20/SS SSOP-20 has a thermal resistance θJA of approximately 90 °C/W per the Microchip PIC16C5X family datasheet, which is adequate for commercial-temperature operation without forced airflow. The device draws less than 10 mA even at 20 MHz full I/O switching, so self-heating is negligible (Estimated: junction temperature rise at 5 V, 20 MHz, and full I/O is below 5 °C above ambient). Avoid placing the IC adjacent to high-power heat sources such as MOSFETs, linear regulators, or transformers on the PCB to minimize thermal gradient across the silicon die.
Route the !MCLR/VPP pin directly to the programming header with a 10 kΩ pull-up to VDD and a 100 nF cap to VSS to ensure in-circuit serial programming (ICSP) reliability. Keep the OSC1/OSC2 traces short (under 10 mm) and symmetric to avoid oscillator start-up failures; guard the crystal with a ground ring tied to VSS. The ICSP data/clock lines (typically shared with RB6/RB7) must not have series resistors above 100 Ω, or the Vih specification may be violated during programming. For ESD-sensitive industrial installations, add a TVS diode on each external connector pin that maps to a PIC I/O.
Compliance Information
RoHS and lead-free per Microchip product page. Not AEC-Q100 qualified — automotive customers should use the -I (industrial) or -E (extended) temperature grades and re-qualify. Part is in obsolete lifecycle status; new designs should migrate to PIC16F5X FLASH family.
