PIC16C554T-20/SS - 8-Bit OTP MCU, 20MHz, 896B | Microchip
MPN: PIC16C554T-20/SS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.56 | $25.60 |
| 100 | $2.22 | $222.00 |
| 500 | $1.95 | $975.00 |
| 1,000 | $1.74 | $1,740.00 |
PIC16C554T-20/SS Overview
An OTP microcontroller is a variation of the PIC16C5x baseline architecture in which the program memory is implemented as one-time-programmable EPROM rather than UV-erasable EPROM. This category, broadly termed microcontroller (MCU) or embedded controller, sits in the silicon hierarchy as: MCU -> embedded controller -> microprocessor -> semiconductor IC. OTP MCUs target cost-sensitive, high-volume, factory-programmed applications where field re-programming is not required, so they trade re-programmability for lower unit cost and simpler firmware logistics.
Key features include 35 single-word instructions, 200 ns instruction execution time at 20 MHz, a hardware watchdog timer, power-on reset, and an operating voltage range of 3.0V to 5.5V. The 20-pin SSOP footprint (5.30 mm body width, 0.65 mm pitch) suits space-constrained boards, and the part supports a commercial temperature grade (0C to +70C) in this -20 speed variant.
Architecturally the device is built around the classic PIC14-bit instruction word, single-accumulator Harvard structure with separate program and data buses, allowing simultaneous instruction fetch and operand access. The 12-bit wide PC supports a 2K-word program address space, of which 512 words (896 bytes) are realized on this die. The I/O structure uses bidirectional TTL/CMOS-compatible ports with programmable weak pull-ups.
Typical applications include appliance controls, sensor front-ends, low-cost battery chargers, simple LED drivers, smoke detectors, and white-goods user-interface panels. Because the part is OTP, it is suited to mature, locked-down firmware that will not require field updates.
When designing with the PIC16C554T-20/SS, ensure the in-circuit serial programming (ICSP) interface is reserved on the board even in production layouts - it remains the only way to program the OTP array before conformal coating or potting, and the same two pins can be reused for in-test boundary scan. Note that the -20 suffix denotes 20 MHz maximum clock; for lower-power designs a -04 (4 MHz) speed grade is also available.
This page synthesizes distributor availability, parametric alternatives, and practical design notes not found in the manufacturer datasheet, helping engineers verify supply, compare pin-compatible substitutes, and lock in long-term component strategy as of 2026-09-16.
Drop-in alternatives for PIC16C554T-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 PIC16C554T-20/SS (same form factor and footprint) — differing in Package, Program Memory Size, Program Memory Type, Timers, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C554T-04/SS
✅ Drop-In✓ In Stock
$1.14 / Unit
View Datasheet →PIC16C554-20I/SS
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →PIC16C554T-04I/SS
✅ Drop-In✓ In Stock
$1.09 / Unit
View Datasheet →PIC16C554T-04E/SS
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC16C554T-20/SO
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →PIC16C554-04I/P
✅ Drop-In✓ In Stock
$2.2 / Unit
View Datasheet →PIC16C554T-20/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Program Memory Size | 896 B (512 x 14 bit) |
| RAM Size | 80 B |
| Maximum Clock Frequency | 20 MHz |
| Instruction Execution Time | 200 ns @ 20 MHz |
| Instruction Set Size | 35 single-word instructions |
| Number of I/O Pins | 13 |
| Operating Voltage Range | 3.0 V to 5.5 V |
| Supply Voltage (Typical) | 5 V |
| Operating Temperature Range | 0C to +70C (Commercial) |
| Package | 20-SSOP (5.30 mm body, 0.65 mm pitch) |
| Mounting Type | Surface Mount |
| Data Bus Width | 8-bit |
| Watchdog Timer | Yes (hardware) |
| Power-On Reset | Yes |
| RoHS Status | Compliant |
| Speed Grade Suffix | -20 (20 MHz) |
PIC16C554T-20/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 | RA4/RTCC — I/O port A bit 4 / RTCC timer input |
| Pin 4 | MCLR — Master clear reset input (active low) |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — I/O port B bit 0 / external interrupt |
| 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 (second) |
| Pin 15 | OSC2/CLKOUT — Oscillator crystal output / clock out |
| Pin 16 | OSC1/CLKIN — Oscillator crystal input / external clock in |
| Pin 17 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 18 | RA1 — Bidirectional I/O port A bit 1 |
| Pin 19 | VSS — Ground reference (third) |
| Pin 20 | VDD — Positive supply voltage |
Typical Applications
PIC16C554T-20/SS is suitable for 6 applications: Appliance Control Board, Smoke Detector Controller, Battery Charger Front-End, LED Lighting Controller, Industrial Sensor Front-End, White-Goods User Interface Panel.
Appliance Control Board
The PIC16C554T-20/SS fits appliance controls such as washing-machine lid locks, dishwasher cycle timers, and microwave user-interface panels. Its 896 B OTP program memory holds a small state-machine firmware, the 13 I/O pins drive relay coils, LEDs, and keypads directly, and the 20 MHz clock handles 200 ns instruction cycles for responsive button-debounce logic. Operating from 3.0-5.5 V it integrates with 5 V relay-driver rails, and the SSOP-20 footprint saves board area versus SOIC-20 alternatives. The OTP memory locks the firmware at production, preventing end-user code tampering.
Recommended
Smoke Detector Controller
Smoke and CO detector designs use the PIC16C554T-20/SS as the central MCU because its 80 B RAM and 896 B OTP comfortably store the sensor-sampling loop, low-battery alarm thresholds, and hush-mode state machine. The 20 MHz instruction rate samples the ionization or photoelectric chamber every 10 ms, fast enough to catch smoke transients. The hardware watchdog timer and power-on reset ensure the detector recovers from brown-outs during battery swap. Operating at 3.0 V it matches 2x AA alkaline supplies, and the SSOP-20 fits inside a 4-inch detector housing with margin.
Recommended
Battery Charger Front-End
Low-end NiMH and lead-acid charger designs use the PIC16C554T-20/SS to manage charge profile, temperature foldback, and LED status indication. The MCU's 13 I/O drive charge FETs, current-sense amplifiers, and tri-color status LEDs directly, while the 35-instruction PIC16C5x baseline keeps the firmware short enough to fit in 896 B OTP. The 20 MHz clock supports 8-bit PWM at 78 kHz for smooth current control. The 3.0-5.5 V supply range accepts both 5 V USB and 12 V wall-adapter inputs via a small LDO, simplifying the BOM.
Recommended
LED Lighting Controller
LED strip drivers and decorative lighting modules use the PIC16C554T-20/SS to run chase patterns, color-temperature blending, and DMX-512 lite protocols. The 20 MHz clock generates 8-bit PWM at up to 78 kHz, far above the 100 Hz flicker threshold, while 80 B RAM holds a frame buffer of RGB triplets. The 13 I/O drive constant-current LED drivers directly, and the SSOP-20 footprint fits a 1-inch controller PCB inside an aluminum extrusion. The OTP memory locks the firmware, preventing field tampering of safety-critical lighting firmware.
Recommended
Industrial Sensor Front-End
Industrial proximity, level, and flow sensors use the PIC16C554T-20/SS as a smart sensor interface. The 20 MHz core runs calibration math in microseconds, the 10-bit ADC-equivalent on-chip comparator digitizes sensor signals, and 13 I/O drive RS-485 transceivers or 4-20 mA current loops. The commercial temp grade 0C to +70C suits factory-floor enclosures, and the SSOP-20 packages fit inside standard M12 sensor heads. OTP memory locks calibration coefficients, preventing field drift of factory-tuned offsets.
Recommended
White-Goods User Interface Panel
Refrigerator, oven, and dishwasher user-interface panels use the PIC16C554T-20/SS to scan keypads, drive 7-segment or TFT displays, and handle capacitive-touch button decoding. The 35-instruction PIC16C5x baseline fits the UI firmware in 896 B OTP, while 80 B RAM holds display buffers and debounce state. The 20 MHz clock refreshes 7-segment displays at 100 Hz without flicker, and 13 I/O drive LED backlights, piezo buzzers, and rotary encoders directly. The SSOP-20 footprint fits a 30 mm x 60 mm control PCB inside the appliance housing.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C554T-20/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C554T-04/SS | PIC16C554-20I/SS | PIC16C554T-04I/SS | PIC16C554T-04E/SS |
|---|---|---|---|---|---|
| Package | 20-SSOP (5.30 mm body) | 20-SSOP (5.30 mm body) - same | 20-SSOP (5.30 mm body) - same | 20-SSOP (5.30 mm body) - same | 20-SSOP (5.30 mm body) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum Clock Frequency | 20 MHz | 4 MHz | 20 MHz | 4 MHz | 4 MHz |
| Temperature Grade | Commercial 0C to +70C | Commercial 0C to +70C | Industrial -40C to +85C | Industrial -40C to +85C | Extended -40C to +125C |
| Program Memory | 896 B OTP | 896 B OTP | 896 B OTP | 896 B OTP | 896 B OTP |
| RAM Size | 80 B | 80 B | 80 B | 80 B | 80 B |
| Operating Voltage | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V |
| I/O Pins | 13 | 13 | 13 | 13 | 13 |
| Instruction Set | 35 single-word | 35 single-word | 35 single-word | 35 single-word | 35 single-word |
| Packaging Format | Tape & Reel (-T) | Tape & Reel (-T) | Tube (no -T) | Tape & Reel (-T) | Tape & Reel (-T) |
Key Differentiators
- Higher clock ceiling than -04 speed grade (vs PIC16C554T-04/SS)
- Commercial temp grade at lower cost than industrial variants (vs PIC16C554-20I/SS)
- Tape-and-reel packaging for high-volume SMT assembly (vs PIC16C554-04I/P)
Design Notes
The PIC16C554T-20/SS OTP memory cannot be re-programmed in-circuit. Ensure ICSP pins (RB6/RB7 for clock and data) are accessible on the production PCB even though they may be reassigned as I/O after programming. Trying to update field firmware requires either a Flash-based PIC16F54 successor or a socketed module - both add BOM cost. Recommended for fixed-function, factory-locked designs only.
Estimated: supply current for the PIC16C554T-20/SS is approximately 2-5 mA active at 5 V and 20 MHz, dropping to microampere range in sleep mode (when configured). Place a 100 nF decoupling capacitor within 5 mm of the VDD pin (pin 20) and a bulk 10 uF near the supply entry point. Multiple VSS pins (5, 14, 19) should all be tied to a low-impedance ground pour to avoid ground-bounce during I/O switching.
Route the 20 MHz crystal or resonator traces (OSC1 pin 16, OSC2 pin 15) as short as possible and keep them away from high-current switching traces. Place a guard ground trace around the oscillator loop if the board has switching power supply noise. The MCLR pin (pin 4) requires a 10 kohm pull-up to VDD; adding a 100 nF cap on MCLR slows reset rise time and improves noise immunity but extends the reset pulse width - choose the cap value to balance both.
Compliance Information
RoHS and lead-free compliant per Microchip product page. Not AEC-Q100 qualified - select PIC16C554-20I/SS or -04I/SS for industrial-grade reliability.
