PIC16C54A-20I/SS - 8-bit OTP MCU 20MHz 12 I/O SSOP-20 | Microchip
MPN: PIC16C54A-20I/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.93 | $3.93 |
| 10 | $3.54 | $35.40 |
| 100 | $3.14 | $314.00 |
| 500 | $2.83 | $1,415.00 |
| 1,000 | $2.51 | $2,510.00 |
PIC16C54A-20I/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and peripheral I/O. The PIC16C5X family sits at the foundational tier of Microchip's 8-bit MCU portfolio, using a RISC Harvard architecture with 12-bit-wide instructions and 8-bit-wide data path, two-level hardware stack, and direct/indirect/relative addressing modes. These parts ship in One-Time-Programmable (OTP) EPROM variants and target cost-sensitive, high-volume embedded control where program code is finalized at production.
Key features of the PIC16C54A-20I/SS include 12 I/O pins, an 8-bit real-time clock/counter (TMR0) with 8-bit prescaler, a Watchdog Timer (WDT) with on-chip RC oscillator for reliable resets, and power-saving SLEEP mode. Power-on reset, power-up timer and oscillator start-up timer eliminate external reset circuitry. The SSOP-20 (5.30 mm body width) is significantly narrower than the PDIP-20 footprint, enabling compact board designs while still offering 20 functional pins.
The PIC16C54A-20I/SS uses CMOS process technology with static (fully static) operation, allowing the clock to be stopped without losing register state - an unusual and useful feature for low-power applications. The 12-bit instruction word provides 2:1 code compression versus typical 8-bit MCUs of its era, allowing tighter code density in 768 bytes of OTP. The PIC16C5X core executes one instruction per instruction cycle (four oscillator clocks), giving 5 MIPS at 20 MHz - more than adequate for control loops, simple protocols and state-machine glue logic.
Typical applications include appliance control (washing machines, microwave ovens, coffee makers), HVAC thermostat controls, security and fire-alarm panels, remote-control transmitters and receivers, and automotive body modules (RKE, lighting). The wide industrial temperature range plus the 4.5V-5.5V supply voltage make it suitable for 5V-only industrial subsystems and battery-backed sensor nodes. Per Microchip, PIC16F54 is the recommended newer migration target with flash memory, identical pinout and same peripherals.
When designing with the PIC16C54A-20I/SS, ensure the OTP memory programming flow matches the chosen programmer (e.g., MPLAB PM3 or PICSTART Plus), because OTP parts can only be programmed once. Use the in-circuit debug header only on the JW (windowed) variants, not on the OTP/SS industrial part. Decouple VDD with a 0.1 uF ceramic plus 10 uF electrolytic placed within 5 mm of the supply pins.
This page consolidates current distributor pricing, drop-in alternative pinouts, and pragmatic design notes that complement the manufacturer datasheet and reference manuals.
Drop-in alternatives for PIC16C54A-20I/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 PIC16C54A-20I/SS (same form factor and footprint) — differing in Package, Timers, Core Architecture, Program Memory Size, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C54A-20/SO
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →PIC16C54A-20/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C54A-20E/SS
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C54A-20I/SO
✅ Drop-In✓ In Stock
$1.15 / Unit
View Datasheet →PIC16C54A-20I/P
✅ Drop-In✓ In Stock
$1.38 / Unit
View Datasheet →PIC16C54A-04/SS
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →PIC16C54-10/SS
✅ Drop-In✓ In Stock
$1.55 / Unit
View Datasheet →PIC16F54-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C54A-20I/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC16C5X RISC (Harvard) |
| Instruction Set Width | 12-bit |
| Data Path Width | 8-bit |
| Program Memory (ROM) | 768 bytes OTP EPROM |
| RAM | 25 bytes |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle | 4 oscillator clocks (1:4) |
| I/O Pins | 12 |
| Timers | 8-bit TMR0 with 8-bit prescaler |
| Hardware Stack | 2 levels |
| Watchdog Timer | Yes (on-chip RC oscillator) |
| Supply Voltage (VDD) | 4.5 V to 5.5 V |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 20-pin SSOP (0.209", 5.30 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC16C54A-20I/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 | T0CKI — Timer0 external clock input / I/O |
| Pin 4 | MCLR — Master Clear reset input (active low) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — Bidirectional I/O port B bit 0 / INT |
| Pin 7 | RB1 — Bidirectional I/O port B bit 1 |
| Pin 8 | RB2 — Bidirectional I/O port B bit 2 |
| Pin 9 | RB3 — Bidirectional I/O port B bit 3 |
| Pin 10 | RB4 — Bidirectional I/O port B bit 4 |
| Pin 11 | RB5 — Bidirectional I/O port B bit 5 |
| Pin 12 | RB6 — Bidirectional I/O port B bit 6 |
| Pin 13 | RB7 — Bidirectional I/O port B bit 7 |
| Pin 14 | VSS — Ground reference |
| Pin 15 | OSC2 — Oscillator crystal output / I/O |
| Pin 16 | OSC1 — Oscillator crystal input / external clock |
| Pin 17 | VDD — Positive supply voltage |
| Pin 18 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 19 | RA1 — Bidirectional I/O port A bit 1 |
| Pin 20 | VSS — Ground reference |
Typical Applications
PIC16C54A-20I/SS is suitable for 6 applications: Washing Machine and Dishwasher Controller, Microwave Oven Control Panel, HVAC Thermostat and Zone Controller, Security and Fire Alarm Panels, Remote-Control Transmitter / Receiver (RKE), Battery-Operated Utility Meter and Sensor Node.
Washing Machine and Dishwasher Controller
The PIC16C54A-20I/SS fits appliance motor-control boards because of its industrial -40C to +85C rating, 5V supply tolerance across brown-out conditions, and 12 digital I/O pins capable of directly driving TRIAC optocouplers, relay coils, and seven-segment LED displays. At 20 MHz (5 MIPS) the OTP MCU easily sequences the wash, rinse and spin cycles with software timers, while the integrated Watchdog Timer recovers the controller from motor-stall noise events without external supervisor hardware. Compared with newer ARM Cortex parts, the PIC16C54A-20I/SS keeps BOM cost below USD 4 in volume, a decisive factor for consumer white goods.
Recommended
Microwave Oven Control Panel
Microwave keypads, LED displays and magnetron timing loops use the PIC16C54A-20I/SS as the single-chip controller because 12 I/O pins handle a 4x4 matrix keypad plus seven-segment or 14-segment displays without external multiplexing logic. The 768-byte OTP holds the cook-time curves, defrost profiles and child-lock state machine, while the 8-bit TMR0 with prescaler drives the beeper PWM and the 50/60 Hz mains reference. OTP is appropriate here because the firmware is frozen at production. The industrial temperature grade lets the same part be reused across geographies without re-qualifying the BOM.
Recommended
HVAC Thermostat and Zone Controller
The PIC16C54A-20I/SS serves as the low-cost supervisory MCU in residential and light-commercial HVAC thermostats. Its 5V-only operation tolerates the rectified 24 VAC thermostat bus after a small buck regulator, the Watchdog Timer protects against brown-outs during compressor cycling, and the 12 I/O interface with thermistor front ends, LCD segment drivers, relay outputs and a one-wire interface to outdoor temperature sensors. With 20 MHz instruction throughput the part runs PID-style thermostat loops at 1 Hz update rate without exhausting CPU margin.
Recommended
Security and Fire Alarm Panels
In PIR motion-detector panels, glass-break modules and conventional fire-alarm control boards the PIC16C54A-20I/SS provides the supervision state machine and indicator-LED multiplexer. Its 4.5-5.5V supply tolerates battery-backed rails under discharge, the Watchdog Timer resets the panel after ESD events on the sensor wiring, and the integrated Power-on Reset eliminates the external MCP130 supervisor. The OTP memory prevents code tampering once the panel is sealed, which is required for some alarm-system certification regimes.
Recommended
Remote-Control Transmitter / Receiver (RKE)
The PIC16C54A-20I/SS is well suited to automotive remote-keyless-entry transmitters and receivers. The 12 I/O drive up to 8 button inputs and 4 LED indicators without external logic, and the integrated SLEEP mode plus Watchdog Timer achieve standby currents well under 1 uA on a coin cell. On the receiver side the part decodes fixed-code or basic rolling-code bit streams, drives an RF module via GPIO, and actuates door-lock relays. The industrial temperature grade is mandatory for the in-car environment from cold-start winter mornings to direct-sunlight summer dashboards.
Recommended
Battery-Operated Utility Meter and Sensor Node
Utility AMR modules, water-meter pulse counters and remote environmental sensor nodes use the PIC16C54A-20I/SS because of its fully static core (clock can be stopped to save power) and Watchdog Timer wake-up. With the internal RC WDT the part wakes from sleep once per second, counts pulses from a reed switch or sensor, averages the result, and transmits via a low-power RF link before going back to sleep. 768 bytes of OTP is enough for the metering algorithm and simple encryption, and the industrial temperature rating survives outdoor enclosures from -40C winters to +85C summer cabinets.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C54A-20I/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C54A-20/SO | PIC16C54A-20E/SS | PIC16C54A-04/SS | PIC16F54-I/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SSOP-20 (5.30 mm) | SOIC-20 - same family, wider body | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 4 MHz (-80%) | 20 MHz |
| Program Memory Type | 768 bytes OTP EPROM | 768 bytes OTP EPROM | 768 bytes OTP EPROM | 768 bytes OTP EPROM | Flash (reprogrammable) |
| Operating Temperature | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +125C (Extended) | -40C to +85C | -40C to +85C (Industrial) |
| 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 | 2.0 V to 5.5 V (wider) |
| I/O Pins | 12 | 12 | 12 | 12 | 12 |
| Replacement / Migration Status | Active, mature | Active | Active | Active | Recommended new design |
Key Differentiators
- Industrial -40C to +85C operating range in compact SSOP-20 (vs PIC16C54A-20/SS)
- 20 MHz operation - 5x faster than 04 MHz grade (vs PIC16C54A-04/SS)
- OTP memory locks firmware against tampering at production (vs PIC16F54-I/SS)
- Surface-mount SSOP-20 saves board area vs PDIP-20 (vs PIC16C54A-20I/P)
Design Notes
Decouple VDD (pin 17) with a 100 nF ceramic plus a 10 uF tantalum or aluminum electrolytic placed within 5 mm of the pin. The PIC16C54A-20I/SS draws roughly 2 mA at 5 V/20 MHz active and below 4 uA in SLEEP mode. For brown-out environments (appliance, automotive) add an MCP130 or equivalent voltage supervisor on MCLR because the internal Power-on Reset alone may not be enough to recover from a slow VDD droop.
Keep the crystal or resonator within 5 mm of OSC1 (pin 16) and OSC2 (pin 15) and route both traces over a continuous ground pour. Avoid routing RB port lines (pins 6-13) parallel to the oscillator traces to prevent injection of switching noise into the clock. The SSOP-20 thermal pad is not present on this package, but a ground flood under the part helps dissipate switching transients in high-I/O-count applications.
OTP (One-Time-Programmable) memory means the firmware cannot be erased once programmed - a bad code lock will scrap the part. Always program a known-good image with the configuration word set correctly (watchdog enable, oscillator mode, code protect bits). The PIC16C54A-20I/SS does NOT have an in-circuit debugger header, so plan for an MPLAB PM3 or PICSTART Plus programmer socket. Use the JW windowed variant only for prototypes.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - the part is industrial-temperature but not automotive-qualified; for AEC-Q100 applications use PIC16F54 equivalent designs.
