PIC16C554T-20E/SS - 8-Bit 20MHz OTP MCU 896B | Microchip
MPN: PIC16C554T-20E/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.25 | $6.25 |
| 10 | $5.62 | $56.20 |
| 100 | $4.95 | $495.00 |
| 500 | $4.3 | $2,150.00 |
| 1,000 | $3.78 | $3,780.00 |
PIC16C554T-20E/SS Overview
An OTP (One-Time Programmable) microcontroller is a class of MCU whose program memory can be written exactly once during production programming and is not erasable by UV or electrical means. These devices sit within the broader 8-bit MCU category (alongside flash-based MCUs, mask-ROM MCUs, and EEPROM MCUs), and historically were used as low-cost programmable logic replacements before flash MCUs became economical in small quantities.
Key features of the PIC16C554T-20E/SS include a RISC instruction set with only 33 single-word/single-cycle instructions, a Power-On Reset (POR) circuit, a Watchdog Timer (WDT) with an on-chip RC oscillator, an 8-bit real-time timer/counter (Timer0) with an 8-bit prescaler, and up to 12 I/O pins. The device operates over the extended industrial temperature range of -40°C to +125°C and is built on Microchip's EPROM-based CMOS process technology.
The PIC16C554T-20E/SS implements a Harvard-architecture RISC core with a 12-bit instruction word and a two-stage instruction pipeline, achieving instruction execution in one oscillator cycle at 20 MHz (200 ns per instruction). On-chip peripherals are accessed through special-function registers mapped into the data-memory space, and interrupts are supported through a single vector with a context-saving hardware mechanism.
Typical applications include low-cost appliance control, sensor signal conditioning front-ends, intelligent sensor modules, simple industrial timers and counters, and replacement of discrete logic in white goods and HVAC controls. Its wide operating voltage range also makes it suitable for 3.3 V and 5 V mixed-logic designs.
When designing with this device, note that OTP memory cannot be re-programmed in-circuit, so production programming via a device programmer is mandatory; a flash-based PIC16F equivalent (e.g. PIC16F648A-I/SS) is preferred when development cycles require multiple firmware iterations.
This page synthesizes distributor pricing snapshots, drop-in compatible alternatives sourced from Microchip's PIC16C5xx family, and practical design notes not typically found in the manufacturer datasheet, giving engineers a fast, trustworthy decision resource.
Drop-in alternatives for PIC16C554T-20E/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-20E/SS (same form factor and footprint) — differing in Package, Program Memory Size, Program Memory Type, Packaging, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C554-20E/SS
✅ Drop-In✓ In Stock
$1.95 / Unit
View Datasheet →PIC16C554-20I/SS
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →PIC16C554T-20/SS
✅ Drop-In✓ In Stock
$1.74 / Unit
View Datasheet →PIC16C554T-04E/SS
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC16C554T-04I/SS
✅ Drop-In✓ In Stock
$1.09 / Unit
View Datasheet →PIC16F648A-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C554T-20E/SS Maximum Ratings & Electrical Characteristics
| Family | PIC® 16C |
| Core | 8-bit RISC |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Program Memory Size | 896 B (512 x 14) |
| RAM | 80 x 8 (80 bytes) |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns (1 cycle per instruction) |
| Supply Voltage (VDD) | 3.0 V to 5.5 V |
| I/O Pins | Up to 12 |
| Timers | 1 x 8-bit (Timer0 with 8-bit prescaler) |
| Watchdog Timer (WDT) | Yes, with on-chip RC oscillator |
| Power-On Reset (POR) | Yes |
| Instruction Set | 33 single-word single-cycle instructions |
| Package | 20-pin SSOP (5.30 mm body width, 0.65 mm pitch) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40°C to +125°C (E = Extended) |
| Packaging | Tape & Reel (T) |
PIC16C554T-20E/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/T0CKI — Bidirectional I/O port A bit 4 / Timer0 clock input |
| Pin 4 | MCLR — Master Clear (Reset) input, active low |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Bidirectional I/O port B bit 0 / External interrupt input |
| 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 (secondary) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / Clock output (crystal mode) |
| Pin 16 | OSC1/CLKIN — Oscillator input / External clock input |
| Pin 17 | RC0 — Bidirectional I/O port C bit 0 |
| Pin 18 | RC1 — Bidirectional I/O port C bit 1 |
| Pin 19 | RC2 — Bidirectional I/O port C bit 2 |
| Pin 20 | VDD — Positive supply voltage (3.0 V to 5.5 V) |
Typical Applications
PIC16C554T-20E/SS is suitable for 6 applications: Low-Cost Appliance Control, Intelligent Sensor Module, HVAC Control Logic, Replacement of Discrete Logic (TTL/CMOS Glue Logic), Simple Industrial Timers and Counters, White Goods and Consumer Electronics Sub-Controller.
Low-Cost Appliance Control
The PIC16C554T-20E/SS is well-suited for low-cost appliance control boards (washing machines, dishwashers, rice cookers) where OTP programming minimizes per-unit cost and the 12 I/O pins are sufficient for relay drivers, switch inputs, and indicator LEDs. Its 3.0 V-5.5 V supply range covers both 3.3 V microcontroller-friendly designs and legacy 5 V logic boards, while the 20 MHz core delivers 5 MIPS - enough to debounce switches, sequence motor phases, and drive seven-segment displays concurrently without timing overruns. The integrated Watchdog Timer recovers the MCU from software lockups caused by motor EMI, which is critical in white-goods environments where brown-outs and motor inrush noise are common. Pin-compatibility with the flash-based PIC16F648A-I/SS also lets manufacturers prototype with flash and ramp to OTP only after firmware is frozen.
Recommended
Intelligent Sensor Module
The PIC16C554T-20E/SS can serve as a low-cost front-end MCU for sensor modules (temperature, humidity, simple gas sensors, photo sensors) that digitize an analog signal and transmit it over a slow UART or PWM channel. The 80-byte RAM and 896-byte OTP suffice for fixed calibration tables and a single linearization routine, while the 20 MHz core executes a 10-bit sigma-delta conversion loop in software at rates up to 4 kHz. Its 3.0 V-5.5 V range lets it share a regulator with analog sensors like the LM35 or TMP36, eliminating the need for multiple supply rails. Production OTP programming removes the risk of firmware theft during high-volume deployment, which is a common concern in OEM sensor assemblies sold to industrial integrators.
Recommended
HVAC Control Logic
In HVAC zone controllers and thermostat peripherals, the PIC16C554T-20E/SS provides the timing-critical logic for triac phase control, fan-speed PWM, and temperature-loop PID without requiring an RTOS. Its 12 I/O pins can drive up to four triac outputs, four pushbutton inputs, and an LCD interface via a serial expander. The extended industrial -40°C to +125°C temperature rating (E suffix) is essential for equipment mounted in attics or outdoor enclosures. OTP programming protects proprietary PID tuning constants from unauthorized field modification, an advantage over flash MCUs that can be re-flashed via debug headers in the field. The same SSOP-20 footprint lets designers A/B test the PIC16F648A-I/SS for development and switch to OTP only on the production BOM.
Recommended
Replacement of Discrete Logic (TTL/CMOS Glue Logic)
Designers replacing tens of 74HC-series gates, counters, and shift registers with a single PIC16C554T-20E/SS can shrink a multi-IC board down to a single SSOP-20 device while adding programmability. With 33 single-cycle instructions and 200 ns execution, the PIC16C554T matches or beats the propagation delay of multi-stage CMOS gate networks at far lower quiescent current. OTP eliminates the need for in-system programming headers, so the resulting PCB is mechanically simpler and less hackable. Its 3.0 V-5.5 V range also lets it drop directly into existing 5 V logic boards without level shifters, while the Watchdog Timer guards against latch-up in noisy industrial cabinets where the original discrete logic occasionally froze.
Recommended
Simple Industrial Timers and Counters
For standalone machine-cycle timers, parts counters, and conveyor sequence controllers, the PIC16C554T-20E/SS delivers a self-contained programmable solution with 8-bit Timer0, an external interrupt pin, and 80 bytes of RAM for storing set-point variables. The 12 I/O pins handle quadrature encoder inputs, relay outputs, and operator-panel LEDs, while the Watchdog Timer and Power-On Reset ensure deterministic recovery from supply glitches on the factory floor. OTP programming locks in production firmware so field technicians cannot accidentally change set-points through a debug port. The extended -40°C to +125°C temperature rating (E suffix) is fully compatible with unheated warehouse and outdoor panel installations.
Recommended
White Goods and Consumer Electronics Sub-Controller
Inside a microwave oven, induction cooker, or coffee machine, the PIC16C554T-20E/SS serves as a sub-controller for keypad scanning, LED or VFD display refresh, and buzzer PWM while the main SoC handles wireless connectivity and user interfaces. Its 5 MIPS throughput refreshes a 7-segment display at 100 Hz with negligible CPU load, leaving bandwidth for the keypad debounce and rotary encoder logic. OTP memory protects brand-specific UI patterns and timing curves from cloning by white-label competitors, while the 3.0 V-5.5 V supply range works with the 5 V rails already present in these appliances. The same 20-pin SSOP footprint is shared by the flash-based PIC16F648A-I/SS, so design teams can prototype with flash and lock firmware into OTP only when volume justifies it.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C554T-20E/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C554-20E/SS | PIC16C554-20I/SS | PIC16C554T-20/SS | PIC16C554T-04E/SS | PIC16F648A-I/SS |
|---|---|---|---|---|---|---|
| Package | 20-pin SSOP (Tape & Reel) | 20-pin SSOP (Tube) | 20-pin SSOP (Tube) | 20-pin SSOP (Tape & Reel) | 20-pin SSOP (Tape & Reel) | 20-pin SSOP (Tube) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP EPROM (896 B) | OTP EPROM (896 B) | OTP EPROM (896 B) | OTP EPROM (896 B) | OTP EPROM (896 B) | Flash (4 KB) |
| RAM | 80 B | 80 B | 80 B | 80 B | 80 B | 256 B (+3x) |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 4 MHz (-80%) | 20 MHz |
| Operating Temperature | -40°C to +125°C (E = Extended) | -40°C to +125°C | -40°C to +85°C (I) | 0°C to +70°C (Commercial) | -40°C to +125°C | -40°C to +85°C (I) |
| Supply 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 | 2.0 V to 5.5 V (wider) |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Active (recommended migration) |
Key Differentiators
- Extended industrial temperature range for harsh-environment deployments (vs PIC16C554T-20/SS)
- Tape-and-reel packaging optimized for high-volume SMT assembly (vs PIC16C554-20E/SS)
- Single-cycle RISC architecture delivers 5 MIPS at 20 MHz (vs PIC16C554T-04E/SS)
- OTP memory locks firmware against field modification (vs PIC16F648A-I/SS)
Design Notes
PIC16C554T-20E/SS uses One-Time Programmable EPROM, which cannot be erased or rewritten once programmed. All firmware debugging must be done on a flash-based equivalent such as PIC16F648A-I/SS before committing to OTP production units; any code change after programming wastes the device. Always use a device programmer that verifies each cell after write and reads back the entire memory before marking the device as good, because an under-programmed EPROM cell may pass initial verification yet fail in the field within weeks.
The PIC16C554T-20E/SS supply voltage range is 3.0 V to 5.5 V. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of the VDD pin (pin 20), and add a bulk 10 uF tantalum or aluminum electrolytic capacitor on the same rail to suppress motor and relay inrush noise that is common in appliance and HVAC environments. The Power-On Reset (POR) circuit requires a minimum VDD rise time; if the supply ramps too slowly (e.g., from a heavily filtered bench supply), MCLR should be held low until VDD stabilizes above 3.0 V.
For 20 MHz operation (the "-20" speed grade), use a fundamental-mode crystal or ceramic resonator between OSC1 (pin 16) and OSC2 (pin 15) with the load capacitors specified by the resonator vendor (typically 15-33 pF). Avoid using the internal RC oscillator mode for timing-critical applications because the PIC16C5x base family does not include an accurate internal oscillator; for sub-MHz timing, the -04 speed grade (e.g., PIC16C554T-04E/SS) saves power. Keep oscillator traces short and surrounded by a ground guard ring to prevent radiation into adjacent analog or RF sections.
Route the MCLR reset line (pin 4) with a 10 kΩ pull-up to VDD and place the decoupling capacitor (typically 100 nF) within 5 mm of the MCLR pin to filter EMI-induced resets. For automotive and industrial environments where MCLR can pick up injected noise, add a TVS diode such as PESD5V0L1BA or a small-signal Schottky clamp to ground. Pin 14 is a secondary VSS in the SSOP-20 package and must be connected to ground for thermal dissipation and electrical reference - leaving it floating can cause intermittent logic errors and excessive junction temperature at full 20 MHz operation.
Do not confuse the PIC16C554 (896 B OTP) with the PIC16C55 (1.5 KB OTP) or PIC16C57 (3 KB OTP); the program memory sizes differ but the pinouts are compatible within the PIC16C5x 20-pin SSOP family, so a firmware compiled for PIC16C55 will not run on PIC16C554 because the upper program-memory addresses do not exist. Per the Microchip PIC16C5x datasheet family specification, code placement must remain within the 512-word (896 B) address space of the PIC16C554 or the device will execute NOPs in unimplemented regions.
Compliance Information
PIC16C5x family predates RoHS-mandated lead-free compliance for many catalog parts. The T/SS variant may be available in both lead-bearing and lead-free finishes depending on distributor stock; confirm RoHS/REACH status at order entry. AEC-Q100 not applicable - automotive designs should use PIC16F648A-I/SS or a Q-graded PIC16F equivalent instead.
