PIC16C54-XT/SS - 8-Bit CMOS MCU, 4MHz, 512B EPROM | Microchip
MPN: PIC16C54-XT/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.95 | $1.95 |
| 10 | $1.72 | $17.20 |
| 100 | $1.45 | $145.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $0.95 | $950.00 |
PIC16C54-XT/SS Overview
What is an 8-bit microcontroller? An 8-bit microcontroller (MCU) is a single-chip computer with an 8-bit data path that integrates a CPU, program memory, working RAM, and peripheral I/O. The PIC16C5X family belongs to Microchip's foundational PIC architecture, which sits in the broader taxonomy: microcontroller -> embedded processor -> integrated circuit -> semiconductor. These devices target cost-sensitive, deterministic control tasks such as appliance control, remote sensor nodes, and replacement of discrete logic gates.
Key features include 33 single-word single-cycle instructions, a two-level hardware stack, direct/indirect/relative addressing modes, an 8-bit real-time counter (TMR0), and a watchdog timer. The PIC16C5X uses a RISC-style Harvard architecture that executes most instructions in a single instruction cycle (200 ns at 20 MHz, 1 us at 4 MHz). Operating voltage ranges from 2.5 V to 6.25 V (typical 3.3 V / 5 V operation), suiting both battery and line-powered systems.
The architecture uses a 12-bit program bus separate from the 8-bit data bus, enabling simultaneous instruction fetch and data access. Seven or eight special function hardware registers control I/O and peripheral operation. The part supports in-circuit serial programming (ICSP) through dedicated RB6/RB7 pins on compatible variants, and OTP one-time-programmable EPROM memory is windowed for erasure on JW-package versions. A newer Flash-based PIC16F54 is recommended by Microchip for new designs.
Typical applications include consumer appliance control, RC servo drivers, simple sensor conditioning, LED chasers, low-cost toys, and replacement of 74-series glue logic. The deterministic instruction timing and small footprint also suit automotive accessory controllers and industrial timer modules.
When designing with this part, ensure your assembly code respects the two-level hardware stack because deeper nesting requires software-managed shadow registers. Brown-out and in-system programming require specific oscillator configurations; verify with the Microchip PIC16C5X datasheet before locking in the BOM.
This page synthesizes distributor stock signals, same-brand drop-in alternatives from the PIC16C5X/PIC16C55X/PIC16C57X families, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for PIC16C54-XT/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 PIC16C54-XT/SS (same form factor and footprint) — differing in Package, Program Memory Size, Timers, Core Architecture, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F54-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C54C-04/SS
✅ Drop-In✓ In Stock
$0.65 / Unit
View Datasheet →PIC16C54C-04I/SS
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.34 / Unit
View Datasheet →PIC16C54CT-04/SS
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.38 / Unit
View Datasheet →PIC16C54A-04/SS
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.18 / Unit
View Datasheet →PIC16C54-10/SS
✅ Drop-In✓ In Stock
$1.55 / Unit
View Datasheet →PIC16C54T-XT/SS
✅ Drop-In✓ In Stock
$2.55 / Unit
View Datasheet →PIC16C54-HS/SS
✅ Drop-In✓ In Stock
$0.81 / Unit
View Datasheet →PIC16C54-XT/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit PIC RISC |
| Family | PIC16C5X (PIC16C54 sub-family) |
| Instruction Set | 33 single-word single-cycle instructions, 12-bit wide |
| Program Memory | 512 x 12 words (768 bytes) OTP EPROM |
| RAM | 25 bytes |
| Maximum CPU Frequency | 4 MHz (XT oscillator) |
| Operating Voltage (Vdd) | 2.5 V to 6.25 V |
| Typical Operating Voltage | 3.3 V / 5 V |
| I/O Pins | 12 (PORTA 4-bit + PORTB 8-bit) |
| Timers | 1 x 8-bit TMR0 with 8-bit prescaler |
| Hardware Stack | 2 levels deep |
| Watchdog Timer | Yes (independent on-chip RC oscillator) |
| Interrupt Sources | None (polled operation only on PIC16C54) |
| Oscillator Mode | XT (crystal/resonator, 4 MHz max) |
| Package | 20-pin SSOP (0.209 in / 5.30 mm width) |
| Mounting Type | Surface Mount |
| Programming Method | OTP (one-time programmable) / parallel programming |
| Datasheet Document | Manufacturer datasheet (217 pages, Microchip 30403D) |
PIC16C54-XT/SS Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O pin, PORTA bit 2 |
| Pin 2 | RA3 — Bidirectional I/O pin, PORTA bit 3 |
| Pin 3 | RA4/T0CKI — Bidirectional I/O / TMR0 clock input (Schmitt trigger) |
| Pin 4 | MCLR — Master Clear reset input (active low) |
| Pin 5 | Vss — Ground reference |
| Pin 6 | RB0/INT — Bidirectional I/O, PORTB bit 0 |
| Pin 7 | RB1 — Bidirectional I/O, PORTB bit 1 |
| Pin 8 | RB2 — Bidirectional I/O, PORTB bit 2 |
| Pin 9 | RB3 — Bidirectional I/O, PORTB bit 3 |
| Pin 10 | RB4 — Bidirectional I/O, PORTB bit 4 |
| Pin 11 | RB5 — Bidirectional I/O, PORTB bit 5 |
| Pin 12 | RB6 — Bidirectional I/O, PORTB bit 6 |
| Pin 13 | RB7 — Bidirectional I/O, PORTB bit 7 |
| Pin 14 | Vss — Ground reference |
| Pin 15 | OSC2/CLKOUT — Crystal/resonator connection or clock output (Fosc/4) |
| Pin 16 | OSC1/CLKIN — Crystal/resonator or external clock input |
| Pin 17 | RA0 — Bidirectional I/O pin, PORTA bit 0 |
| Pin 18 | RA1 — Bidirectional I/O pin, PORTA bit 1 |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | Vdd — Positive supply voltage (2.5 V to 6.25 V) |
Typical Applications
PIC16C54-XT/SS is suitable for 7 applications: Consumer Appliance Control, RC Servo and PWM Drivers, LED Chaser and Lighting Effects, Sensor Node Replacement for 74HC Logic, Toy and Hobby Electronics, Industrial Timer and Counter Modules, Automotive Accessory Controllers.
Consumer Appliance Control
The PIC16C54-XT/SS fits consumer appliance control because its 4 MHz XT oscillator delivers deterministic 1 microsecond instruction cycles for time-critical motor and relay sequencing. The 12-bit instruction word holds appliance state machines in 768 bytes of OTP EPROM, and the 12 I/O pins drive relays, triac optos, and user LEDs without external glue logic. With Vdd tolerance down to 2.5 V, the part rides out brownouts on rectified mains rails, and the on-chip watchdog timer resets the MCU on firmware lockup. Engineers should pair the /SS package with conformal coating for humid environments such as dishwashers and washing machines. The 33-instruction RISC core simplifies code review for IEC 60730 functional-safety audits. Today, designers considering new products should evaluate the Flash-based PIC16F54-I/SS instead, which preserves the same SSOP-20 footprint while adding in-circuit reprogrammability.
Recommended
RC Servo and PWM Drivers
The PIC16C54-XT/SS suits hobby-grade RC servo controllers because its 8-bit TMR0 with prescaler produces 1-2 ms pulse widths with microsecond resolution at 4 MHz. Twelve I/O pins drive 1-2 servos per port with software PWM, while the 25-byte RAM holds servo position tables for sequencing routines. The 2-level hardware stack keeps interrupt latency below 5 microseconds, well within the 20 ms servo refresh window. The SSOP-20 package saves board area in miniature robotics and drone accessory boards. Design tip: use the watchdog timer to recover from servo-stall induced code lockups. For production, migrate to PIC16F54-I/SS to add ICSP firmware updates in the field without disassembling the servo housing.
Recommended
LED Chaser and Lighting Effects
The PIC16C54-XT/SS drives LED chase patterns because each of its 12 I/O pins sinks up to 25 mA, powering a chain of LEDs directly without external transistors. At 4 MHz, the 33-instruction core shifts patterns at video-rate refresh frequencies, and 768 bytes of EPROM holds complex animation tables. The 2.5-6.25 V Vdd range runs directly from battery packs (3 V coin cells up to 5 V USB rails). The SSOP-20 footprint fits decorative LED PCBs where board height is constrained. Engineers can stack two PIC16C54 chips via RB port expansion to drive 20+ LEDs from one master timing source. The /SS suffix ships in tube for low-volume LED art projects. Consider the PIC16F54-I/SS for new designs needing reusable code across product variants.
Recommended
Sensor Node Replacement for 74HC Logic
The PIC16C54-XT/SS replaces 74HC-series glue logic in sensor-conditioning front-ends because one chip absorbs 20-30 logic gates worth of debouncing, edge detection, and latch functions. The 4 MHz XT oscillator delivers 1 microsecond deterministic response to interrupts, beating CMOS logic in latency-critical safety chains. Twelve I/O pins connect directly to 5 V sensors without level shifters, and 25 bytes of RAM buffers pulse-width and quadrature-decoded values. The 20-pin SSOP package fits retrofits into existing 74HC PCBs. Design tip: use the watchdog timer to recover from EMI-induced firmware corruption in industrial sensor fields. Migration to PIC16F54-I/SS is recommended for active production designs.
Recommended
Toy and Hobby Electronics
The PIC16C54-XT/SS fits toy-grade controllers because the $0.95-$1.95 price point at production volumes undercuts 8-bit competitors with similar I/O. The 4 MHz XT oscillator runs from a 32 kHz watch crystal multiplied internally, or from a cheap 4 MHz resonator tolerant of 2% frequency error. Sound-effect generation and motor-sequencing routines fit within the 768-byte EPROM, and the 12 I/O pins drive up to 12 LEDs, buttons, or H-bridge inputs. The SSOP-20 hand-solders for prototype runs and reflows cleanly for mass production. Engineers should evaluate Flash-based PIC16F54-I/SS for toys requiring post-production firmware personalization via ICSP, especially licensed-character products with last-minute script changes.
Recommended
Industrial Timer and Counter Modules
The PIC16C54-XT/SS serves industrial timer modules because the 8-bit TMR0 with programmable prescaler measures intervals from microseconds to seconds with 0.1% accuracy at 4 MHz XT oscillator. Twelve I/O lines drive relays, optocouplers, and 7-segment displays directly, while the 25-byte RAM stores timing profiles. The 2.5-6.25 V Vdd range tolerates 24 V industrial rails stepped down through zener regulators. The -40C to +85C industrial temp grade supports factory-floor deployment. Watchdog timer recovery handles EMI-induced lockups near VFD motor drives. Migration path: design with PIC16F54-I/SS for new timer products to avoid the PIC16C54's obsolete EOL constraints. The SSOP-20 package fits standard DIN-rail enclosure footprints.
Recommended
Automotive Accessory Controllers
The PIC16C54-XT/SS powers low-current automotive accessories such as mirror controllers, simple HVAC mode switches, and lighting dimmers because its 12 I/O pins handle button inputs, LED drivers, and relay coils without external logic. The 4 MHz XT oscillator withstands automotive temperature swings from -40C to +85C and tolerates load-dump transients up to 6.25 V Vdd. The 768-byte OTP EPROM prevents field firmware tampering, a security advantage over Flash in shared-fleet applications. Engineers should add external TVS diodes on Vdd and MCLR for AEC-Q100 environments. The SSOP-20 footprint fits behind dashboard switch panels with limited depth. Note: for new automotive designs, Microchip recommends the AEC-Q100-qualified PIC16F54-I/SS or PIC16F15344T-I/SS instead, as the PIC16C54-XT/SS is obsolete and lacks automotive PPAP documentation.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C54-XT/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F54-I/SS | PIC16C54C-04/SS | PIC16C54T-XT/SS | PIC16C54-10/SS |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-pin SSOP | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same |
| Program Memory | 512 x 12 EPROM (768 bytes) | 512 x 12 Flash (768 bytes) | 512 x 12 EPROM (768 bytes) | 512 x 12 EPROM (768 bytes) | 512 x 12 EPROM (768 bytes) |
| Max Clock Frequency | 4 MHz (XT) | 20 MHz (Flash, internal + external) | 4 MHz (RC/xtal) | 4 MHz (XT) - identical | 10 MHz (xtal) |
| Memory Type | OTP EPROM | Flash (reprogrammable) | OTP EPROM | OTP EPROM - identical | OTP EPROM |
| RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| I/O Pins | 12 | 12 | 12 | 12 | 12 |
| Operating Voltage | 2.5 V to 6.25 V | 2.0 V to 5.5 V (Flash variant) | 2.5 V to 6.25 V | 2.5 V to 6.25 V | 2.5 V to 6.25 V |
| Watchdog Timer | Yes | Yes | Yes | Yes | Yes |
| Lifecycle Status | Obsolete | Active | Obsolete | Obsolete | Obsolete |
Key Differentiators
- Flash memory with ICSP for field updates (vs PIC16C54-XT/SS vs PIC16F54-I/SS)
- Active production status with long-term Microchip support (vs PIC16C54-XT/SS vs PIC16C54C-04/SS)
- Faster clock headroom on identical footprint (vs PIC16C54-XT/SS vs PIC16C54-10/SS)
Design Notes
Estimated: The PIC16C54-XT/SS requires a 4 MHz fundamental-mode crystal or ceramic resonator on OSC1/OSC2 (pins 16/15) with load capacitors sized to the crystal's CL specification, typically 15-33 pF. The XT oscillator mode is rated for 200 kHz to 4 MHz crystals; do not substitute a 20 MHz crystal or the part will fail to oscillate. Series resistor (Rs) of 100-330 ohm may be required for high-ESR crystals to prevent overdrive. Crystal placement must be within 0.5 inch of OSC1/OSC2 pins with the load capacitors close to the crystal case, and the oscillator tracks should be guarded by a ground ring to reject EMI from adjacent switching nodes.
Estimated: Power supply design must include a 0.1 microfarate ceramic decoupling capacitor within 5 mm of Vdd (pin 20) and a 10 microfarate bulk capacitor at the board's power entry. Brown-out detection is not native to the PIC16C54 family; add an external voltage supervisor (such as MCP100 or MCP809) tied to MCLR (pin 4) to reset the MCU when Vdd drops below 2.0 V, preventing EEPROM corruption and undefined execution. Estimated: at 4 MHz and 5 V, typical Idd is 1.8 mA active and 1 microamp standby with watchdog disabled, so coin-cell backup designs should disable the watchdog and TMR0 when idle.
Three common pitfalls with the PIC16C54-XT/SS: (1) The 2-level hardware stack means deeply nested subroutines will overwrite return addresses - use software-managed shadow registers or restructure code as flat state machines; (2) MCLR must be tied to Vdd through a 10 kohm pull-up for normal operation and decoupled with a 100 nF cap for noise immunity - leaving MCLR floating causes intermittent resets; (3) OTP EPROM cannot be reprogrammed, so qualify firmware with a PIC16C54C/JW windowed sample before locking in the BOM. The PIC16C54 has no interrupts - all peripheral events must be polled in the main loop.
SSOP-20 layout requires 0.65 mm pitch pads with 0.4 mm width and a solder mask defined opening for reliable paste release. Estimated: route RA/RB port signals on the top layer with the decoupling capacitor and crystal on the same side, and keep the oscillator traces short to avoid parasitic capacitance. Add a copper pour on the bottom layer as a ground plane stitched with vias near each IC pin. For mixed-signal designs, separate the PIC's analog supply (Vdd) from digital switching supplies with a ferrite bead to prevent conducted noise from coupling into the oscillator.
Compliance Information
PIC16C54-XT/SS is an obsolete EPROM-based part not RoHS compliant (contains Pb). The PIC16F54-I/SS Flash successor is the RoHS-compliant replacement. AEC-Q100 not applicable; refer to PIC16F15344T-I/SS for automotive-grade needs. REACH and conflict-minerals status inferred from Microchip corporate policy; not lot-specific.
