PIC16C55A-04E/SP - 4MHz 8-Bit OTP MCU 768B | Microchip
MPN: PIC16C55A-04E/SP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.07 | $30.70 |
| 100 | $2.71 | $271.00 |
| 500 | $2.32 | $1,160.00 |
| 1,000 | $2.05 | $2,050.00 |
PIC16C55A-04E/SP Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, I/O peripherals, and often analog blocks into one package. The PIC16C5X belongs to the RISC (Reduced Instruction Set Computer) architecture lineage, designed for deterministic execution and low parts count in embedded designs. Within the broader taxonomy, this part sits as: microcontroller -> embedded controller -> semiconductor IC -> integrated circuit. Its baseline (12-bit instruction) architecture distinguishes it from mid-range (14-bit) and enhanced (16-bit) PIC families.
Key features of the PIC16C55A include a 4 MHz maximum oscillator frequency, 2.0V to 6.25V operating voltage range (suitable for both 3.3V and 5V rails as noted in distributor datasheets), 20 digital I/O pins, a watchdog timer for code-flow safety, and an internal reset circuit. The 28-SPDIP package is the original through-hole form factor preferred for prototyping, hobbyist designs, and legacy industrial controllers where socketed or hand-soldered assembly remains common.
Technically, the PIC16C55A uses a Harvard architecture with separated program and data paths, two-stack-level subroutine nesting, and a hardware-friendly instruction set optimized for C and assembly code density. The OTP memory supports one-time field programming for production volumes, with the -04E speed designation indicating the 4 MHz extended temperature grade suitable for industrial environments.
Typical applications include legacy industrial control, appliance controllers, simple sensor interfaces, hobbyist and educational projects, and replacement of older discrete logic glue circuits. The wide voltage tolerance and deterministic interrupt handling also make it attractive for cost-sensitive automotive subsystems and standalone sensor readers.
When designing with the PIC16C55A, remember that OTP memory cannot be rewritten, so code must be fully verified before final programming. The 28-SPDIP footprint is compatible with standard IC sockets and breadboards, simplifying field service and rapid iteration. For new designs consider PIC16F equivalents for Flash-based reprogrammability.
This page synthesizes verified distributor pricing, parametric comparison tables, and same-package drop-in alternatives not found in the bare manufacturer datasheet, plus practical engineering notes for engineers evaluating the PIC16C55A-04E/SP.
Drop-in alternatives for PIC16C55A-04E/SP — 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 PIC16C55A-04E/SP (same form factor and footprint) — differing in Package, Program Memory Size, Timers, Maximum Clock Frequency, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55A-04/SP
✅ Drop-In✓ In Stock
$2.13 / Unit
View Datasheet →PIC16C55A-20/SP
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$3.69 / Unit
View Datasheet →PIC16C55-10/SP
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.45 / Unit
View Datasheet →PIC16C55A-04I/SP
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C54C-04/P
✅ Drop-In✓ In Stock
$1.71 / Unit
View Datasheet →PIC16C554-04/P
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.85 / Unit
View Datasheet →PIC16C55A-04E/SP Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC16C5X (baseline, 12-bit instruction) |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 768 B (512 x 12) |
| RAM Size | 25 B |
| Maximum Clock Frequency | 4 MHz |
| Operating Voltage Range | 2.0V to 6.25V (3.3V / 5V rails) |
| Number of I/O Pins | 20 |
| Package | 28-SPDIP (SP) |
| Mounting Type | Through-Hole (DIP) |
| Pin Count | 28 |
| Operating Temperature | -40C to +125C (Extended, -E suffix) |
| Watchdog Timer | Yes |
| Instruction Set Width | 12-bit |
| Data EEPROM | Not present |
| ADC | Not present (baseline family) |
| MSL Level | 1 (unsealed/through-hole) |
PIC16C55A-04E/SP 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/VPP — Master Clear reset (active low) / programming voltage input |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Bidirectional 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 |
| Pin 15 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 16 | OSC2/CLKOUT — Oscillator crystal output / clock output (Fosc/4) |
| 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 | RC3 — Bidirectional I/O port C bit 3 |
| Pin 21 | RC4 — Bidirectional I/O port C bit 4 |
| Pin 22 | RC5 — Bidirectional I/O port C bit 5 |
| Pin 23 | RC6 — Bidirectional I/O port C bit 6 |
| Pin 24 | RC7 — Bidirectional I/O port C bit 7 |
| Pin 25 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 26 | RA1 — Bidirectional I/O port A bit 1 |
| Pin 27 | VDD — Positive supply voltage |
| Pin 28 | VDD — Positive supply voltage |
Typical Applications
PIC16C55A-04E/SP is suitable for 6 applications: Legacy Industrial Control Systems, Appliance Controllers (White Goods), Hobbyist and Educational Projects, Sensor Interface Front-Ends, Automotive Subsystem Controllers, Logic Circuit Consolidation (Glue Logic Replacement).
Legacy Industrial Control Systems
The PIC16C55A-04E/SP's 20 GPIO pins, 4 MHz deterministic 8-bit RISC core, and 2.0V-6.25V wide supply tolerance make it well-suited to legacy industrial control panels where 5V unregulated rails are common. Its 768-byte OTP memory is sufficient for state machines, relay drivers, and sensor polling loops. The 28-SPDIP package supports IC socket replacement during field service, allowing rapid swap-out of failed units on long-deployed machine lines. Watchdog timer adds resilience in electrically noisy factory environments where MCU lockups must trigger automatic recovery.
Recommended
Appliance Controllers (White Goods)
Appliance controllers for washing machines, dishwashers, and small kitchen equipment benefit from the PIC16C55A-04E/SP's cost-optimized OTP memory and deterministic interrupt response. Its 20 I/O pins can drive 7-segment displays, button matrices, relay coils, and triac interfaces directly through current-limiting resistors. The extended -40C to +125C temperature grade handles under-cabinet and back-of-appliance thermal environments. Established production stability of the 16C5X family reduces BOM risk for high-volume appliance OEMs that have qualified the platform over decades.
Recommended
Hobbyist and Educational Projects
The PIC16C55A-04E/SP's 28-SPDIP through-hole package drops into breadboards and IC sockets, making it a familiar building block for hobbyists learning embedded programming. Its simple baseline instruction set (33 instructions) is approachable for beginners transitioning from Arduino to bare-microcontroller development. The 4 MHz speed is sufficient for LED chasers, simple PWM-free motor drivers, sensor polling stations, and educational timing demonstrations. While OTP prevents in-circuit reprogramming, hobbyists can use windowed PIC16C5X variants for iterative development then deploy OTP parts for final builds.
Recommended
Sensor Interface Front-Ends
Standalone sensor interface boards for temperature, humidity, and discrete switch reading benefit from the PIC16C55A-04E/SP's 20 GPIO pins and low operating voltage range. The 8-bit RISC core provides deterministic scan times for polled sensor arrays used in HVAC, agriculture, and environmental monitoring. With 25 bytes RAM, the device handles small moving-average filters and debounce routines without external logic. The wide 2.0V-6.25V supply supports both battery-powered sensor nodes (using 2xAA at 3V) and 5V industrial backplanes without level shifters.
Recommended
Automotive Subsystem Controllers
Automotive interior accessories, lighting controllers, and small motor drivers use the PIC16C55A-04E/SP for its extended temperature grade and automotive supply voltage tolerance up to 6.25V. Its 20 GPIO pins handle switch inputs, LED drivers, and small relay control without external logic. The watchdog timer recovers from voltage transients common in automotive electrical environments. While the baseline family lacks CAN/LIN peripherals, the part remains useful for simple body-electronics nodes where a network interface is unnecessary.
Recommended
Logic Circuit Consolidation (Glue Logic Replacement)
Designers often replace clusters of 74-series TTL logic gates with a single PIC16C55A-04E/SP for cost reduction in mature products. The 8-bit core executes state machines equivalent to dozens of discrete gates, while the 20 I/O pins replace multi-chip decoder/latch/mux arrangements. The 4 MHz clock provides microsecond response suitable for control loops, sequence logic, and simple data formatting. The OTP memory and 25-byte RAM support custom encoding tables and timing parameters that would otherwise require PALs or small FPGAs.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55A-04E/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55A-04/SP | PIC16C55A-20/SP | PIC16C55-10/SP | PIC16C55A-04I/SP | PIC16C54C-04/P | PIC16C554-04/P |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SPDIP (SP) | 28-SPDIP (SP) - same | 28-SPDIP (SP) - same | 28-SPDIP (SP) - same | 28-SPDIP (SP) - same | 28-PDIP (P) - same DIP-28 family | 28-PDIP (P) - same DIP-28 family |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 20 MHz | 10 MHz | 4 MHz | 4 MHz | 4 MHz |
| Program Memory | 768 B (512 x 12) OTP | 768 B OTP | 768 B OTP | 768 B OTP | 768 B OTP | 768 B OTP | 768 B OTP |
| RAM Size | 25 B | 25 B | 25 B | 25 B | 25 B | 25 B | 80 B |
| Number of I/O Pins | 20 | 20 | 20 | 20 | 20 | 12 | 13 |
| Operating Voltage Range | 2.0V to 6.25V | 2.0V to 6.25V | 3.0V to 5.5V | 2.0V to 6.25V | 2.0V to 6.25V | 2.0V to 6.25V | 2.5V to 5.5V |
| Operating Temperature Range | -40C to +125C (Extended) | 0C to +70C (Commercial) | -40C to +125C (Extended) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +85C (Industrial) |
| UART Peripheral | No | No | No | No | No | No | Yes (SCI) |
Key Differentiators
- Extended-temperature OTP variant for harsh environments (vs PIC16C55A-04/SP)
- Higher-speed upgrade path within same package (vs PIC16C55A-04/SP)
- 20 I/O pins in baseline family (vs PIC16C54C-04/P)
- 2.0V to 6.25V wide supply tolerance (vs PIC16C554-04/P)
Design Notes
The PIC16C55A-04E/SP operates from 2.0V to 6.25V; place a 100 nF decoupling capacitor as close as possible to VDD pins (27 and 28) and a bulk 10 uF electrolytic on the supply rail. Estimated: at 4 MHz clock and typical CMOS I/O loading, the active supply current is around 1-2 mA. For battery-powered sensor nodes powered from 2xAA cells, ensure brown-out detection below 2.0V is implemented in firmware to avoid undefined MCU state.
OTP memory cannot be re-programmed: ensure code is fully verified before final programming. The PIC16C55A uses MCLR/VPP shared pin (pin 4) - connect a 10 kohm pull-up to VDD for normal operation, and ensure the programmer does not interfere with the in-circuit reset path. Watchdog timer must be cleared periodically in firmware; failure to clear it within the WDT timeout will reset the MCU unexpectedly.
Place the 28-SPDIP socket (or directly soldered part) so the notch/dimple indicator is at the top-left of the PCB silkscreen, matching pin 1 orientation. Keep crystal/ceramic resonator traces short (under 10 mm) and route OSC1/OSC2 traces over a continuous ground plane to minimize EMI coupling. If using a 2-pin ceramic resonator, add 10-33 pF load capacitors per the resonator datasheet. Estimated: stray capacitance above 20 pF on OSC1 can shift oscillator frequency by 1-2%.
For through-hole 28-SPDIP designs, route port A, B, and C traces away from analog-sensitive sections (if mixing with analog on the same board). When driving relays or triacs, place flyback/snubber components within 10 mm of the load, and use separate ground return traces for high-current switching to avoid logic-level noise injection into the MCU. The PIC16C55A's 25 mA per-pin sink capability is sufficient for direct LED drive but not for relay coils - use a transistor driver.
Compliance Information
RoHS/REACH compliance status not provided in the verified web data; flagged as [DATA_NEEDED: RoHS status] in specs. PIC16C55A family is not AEC-Q100 qualified for automotive - use PIC16F1825 or PIC16F88 for automotive-grade Flash replacements.
