PIC16C55A-20E/SP - 8-Bit 20MHz OTP MCU 768B | Microchip
MPN: PIC16C55A-20E/SP ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.92 | $8.92 |
| 10 | $8.04 | $80.40 |
| 100 | $7.18 | $718.00 |
| 500 | $6.46 | $3,230.00 |
| 1,000 | $5.74 | $5,740.00 |
PIC16C55A-20E/SP Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, working RAM, and peripheral interfaces into one package. The PIC16C5X baseline family uses a 12-bit-wide instruction set with a RISC architecture, delivering roughly 2:1 code compression over competing 8-bit MCUs in the same price class - meaning engineers can fit equivalent application logic in half the program memory. OTP program memory lets manufacturers ship pre-programmed parts at low cost without exposing internal flash to outside programming.
Key features of the PIC16C55A include 20 I/O pins, a Power-On Reset (POR) circuit, a Watchdog Timer (WDT) for runaway code recovery, an 8-bit timer/counter, and a 4 MHz internal RC oscillator option. The device operates across 3.0V to 6.25V (industrial Vdd range typical for PIC16C5X) and consumes very low active current, suiting battery and line-powered embedded designs. The PIC16C5X 12-bit instruction width keeps the decoder compact and predictable for deterministic control loops.
Typical applications include appliance control boards, simple sensor signal conditioning, LED driver sequencing, automotive body controllers (with the E temp grade), HVAC fan/timer logic, and industrial relay-driver replacement logic. The 28-pin SPDIP footprint is also convenient for breadboarding and educational use because it fits standard DIP sockets and through-hole prototyping boards.
When designing with the PIC16C55A-20E/SP, plan for OTP programming flow using the MPLAB PM3 programmer or compatible device programmer, since OTP parts cannot be re-programmed in-circuit after the programming window is closed. Use the WDT and POR together for robust field recovery, and budget the 25-byte RAM carefully - this is a baseline PIC, not a mid-range PIC16F, so C-stack depth and large buffers will exhaust RAM quickly.
Drop-in alternatives for PIC16C55A-20E/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-20E/SP (same form factor and footprint) — differing in Package, Program Memory Size, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55A-20/SP
✅ Drop-In✓ In Stock
$3.69 / Unit
View Datasheet →PIC16C55A-04E/SP
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →PIC16C55A-04/P
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.18 / Unit
View Datasheet →PIC16C55A-20I/SP
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$3.01 / Unit
View Datasheet →PIC16C55A-20E/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$5.65 / Unit
View Datasheet →PIC16F57-I/SP
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C55A-20E/SP Maximum Ratings & Electrical Characteristics
| Product Family | PIC16C5X (PIC® 16C baseline) |
| Core Architecture | 8-bit RISC, 12-bit instruction word |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 768 B (512 x 12-bit words) |
| RAM | 25 B |
| Maximum Clock Frequency | 20 MHz |
| Operating Voltage (Vdd) | 3.0 V to 6.25 V (industrial range per datasheet) |
| I/O Pins | 20 |
| Timers | 1 x 8-bit timer/counter |
| Watchdog Timer (WDT) | Yes |
| Power-On Reset (POR) | Yes |
| Internal RC Oscillator | 4 MHz typical (nominal) |
| Temperature Grade | Extended Industrial (-40C to +125C), "E" suffix |
| Package | 28-pin SPDIP (SP), through-hole DIP, 0.300 in / 7.62 mm row pitch |
| Mounting Type | Through-Hole |
| Terminal Form / Pin Count | Through-Hole, 28 terminals |
PIC16C55A-20E/SP Pin Configuration
| Pin 1 | RA2 — Port A digital I/O bit 2 |
| Pin 2 | RA3 — Port A digital I/O bit 3 |
| Pin 3 | RA4/T0CKI — Port A digital I/O bit 4 / Timer0 clock input |
| Pin 4 | MCLR — Master Clear (reset) input, active low |
| Pin 5 | Vss — Ground reference |
| Pin 6 | RB0/INT — Port B digital I/O bit 0 / External interrupt input |
| Pin 7 | RB1 — Port B digital I/O bit 1 |
| Pin 8 | RB2 — Port B digital I/O bit 2 |
| Pin 9 | RB3 — Port B digital I/O bit 3 |
| Pin 10 | RB4 — Port B digital I/O bit 4 |
| Pin 11 | RB5 — Port B digital I/O bit 5 |
| Pin 12 | RB6 — Port B digital I/O bit 6 |
| Pin 13 | RB7 — Port B digital I/O bit 7 |
| Pin 14 | Vdd — Positive supply voltage (3.0V to 6.25V) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / clock out |
| Pin 16 | OSC1/CLKIN — Oscillator input / clock in |
| Pin 17 | RC0 — Port C digital I/O bit 0 |
| Pin 18 | RC1 — Port C digital I/O bit 1 |
| Pin 19 | RC2 — Port C digital I/O bit 2 |
| Pin 20 | RC3 — Port C digital I/O bit 3 |
| Pin 21 | RC4 — Port C digital I/O bit 4 |
| Pin 22 | RC5 — Port C digital I/O bit 5 |
| Pin 23 | RC6 — Port C digital I/O bit 6 |
| Pin 24 | RC7 — Port C digital I/O bit 7 |
| Pin 25 | RA0 — Port A digital I/O bit 0 |
| Pin 26 | RA1 — Port A digital I/O bit 1 |
| Pin 27 | RA5 — Port A digital I/O bit 5 |
| Pin 28 | RA6 — Port A digital I/O bit 6 |
Typical Applications
PIC16C55A-20E/SP is suitable for 6 applications: Appliance Control Boards, Automotive Body Controllers, Industrial Sensor Signal Conditioning, HVAC Fan and Timer Logic, LED Display and Sign Sequencers, Educational and Hobby Embedded Boards.
Appliance Control Boards
The PIC16C55A-20E/SP fits appliance control boards (washing machines, dishwashers, microwave ovens) because its 20 MHz instruction rate at 5 MIPS gives ample throughput for motor control loops, its 20 I/O pins directly drive seven-segment displays and keypads, and the Extended Industrial -40C to +125C temperature grade survives hot laundry-room and kitchen-cabinet environments. With 768 bytes of OTP program memory, manufacturers lock the firmware once and ship sealed units at low BOM cost. The internal Watchdog Timer plus Power-On Reset protects against brown-outs during compressor inrush cycles. Unlike mid-range PIC16F parts, OTP forces suppliers to absorb firmware-iteration costs, but in return the part is roughly 30% cheaper per unit.
Recommended
Automotive Body Controllers
For automotive body controllers (window lifters, mirror adjusters, seat-position memory), the PIC16C55A-20E/SP is selected because the "E" suffix guarantees operation across -40C to +125C - matching the AEC-Q100 Grade 1 thermal envelope used for non-safety body modules. The 20 MHz baseline core handles LIN-bus software UART bit-banging and PWM mirror-fold sequencing without saturating the 25-byte RAM. Power-On Reset and Watchdog Timer together survive the cranking-voltage transients common in 12V automotive harnesses. Compared with the PIC16F57 successor, the OTP variant favors cost-driven sealed production where firmware is frozen after validation.
Recommended
Industrial Sensor Signal Conditioning
In industrial sensor-interface boards (4-20 mA loop transmitters, thermocouple front-ends, limit-switch multiplexers), the PIC16C55A-20E/SP serves as a low-cost digital front-end that linearizes analog inputs and formats data for upstream PLCs. The 20 MHz clock performs 10-bit software ADC conversions in under 200 us per channel, the 20 I/O pins route multiple sensor channels, and the Extended Industrial temperature rating supports outdoor or cabinet-mounted deployments. The PIC16C5X baseline 12-bit instruction set keeps deterministic loop timing, which is critical for IEC 61131-style control loops. Compared with discrete logic implementations, this MCU cuts board area roughly 4x.
Recommended
HVAC Fan and Timer Logic
The PIC16C55A-20E/SP is well matched to HVAC fan controllers, defrost timers, and zone-damper actuators because the Extended Industrial -40C to +125C grade operates in attic, rooftop, and refrigeration-coil environments, while the 8-bit timer/counter generates accurate PWM for variable-speed blower motors. The 25-byte RAM is sufficient for state machines tracking fan mode, setpoint, and hysteresis without paging to external memory. Power-On Reset survives compressor brown-outs, and the Watchdog Timer recovers from firmware faults that could otherwise leave a damper stuck open. Compared with mechanical cam timers, this MCU cuts assembly cost by roughly 50%.
Recommended
LED Display and Sign Sequencers
For LED message signs, scrolling marquees, and channel-letter animators, the PIC16C55A-20E/SP drives 20 outputs directly - enough to multiplex an 8-digit 7-segment display with row/column scan - and the 20 MHz instruction rate refreshes the display without visible flicker at typical 100 Hz rates. The 768-byte OTP stores character tables and animation sequences compactly. The "E" temperature grade suits outdoor sign installations exposed to direct sunlight and winter cold. Compared with discrete 555-based sequencers, this MCU replaces 4-6 analog ICs and lets designers re-target firmware per sign via OTP programming.
Recommended
Educational and Hobby Embedded Boards
The PIC16C55A-20E/SP in SPDIP-28 remains popular in university embedded courses and hobbyist projects because the through-hole package fits standard 28-pin DIP sockets and breadboards without surface-mount rework. The PIC16C5X 12-bit baseline instruction set is small enough (35 instructions) for students to master in one semester, and the 25-byte RAM forces disciplined memory budgeting - a useful teaching constraint. The Extended Industrial temp grade also lets lab projects survive accidental shorts and overheating better than finer-pitch parts. Compared with modern 32-bit dev boards, the PIC16C55A keeps the focus on fundamentals: I/O, timers, interrupts, and assembly.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55A-20E/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55A-20/SP | PIC16C55A-04E/SP | PIC16C55A-04/P | PIC16C55A-20I/SP | PIC16C55A-20E/SO | PIC16F57-I/SP |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SPDIP-28 (SP) | SPDIP-28 (SP) - same | SPDIP-28 (SP) - same | SPDIP-28 (SP) - same | SPDIP-28 (SP) - same | SOIC-28 (SO) - surface mount | SPDIP-28 (SP) - same |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 4 MHz | 4 MHz | 20 MHz | 20 MHz | 20 MHz |
| Program Memory | 768 B OTP (512 x 12) | 768 B OTP | 768 B OTP | 768 B OTP | 768 B OTP | 768 B OTP | 2K words Flash |
| RAM | 25 B | 25 B | 25 B | 25 B | 25 B | 25 B | 72 B |
| Temperature Grade | Extended Industrial (-40C to +125C) | Commercial (0C to +70C) | Extended Industrial (-40C to +125C) | Commercial (0C to +70C) | Industrial (-40C to +85C) | Extended Industrial (-40C to +125C) | Industrial (-40C to +85C) |
| Memory Type | OTP (one-time programmable) | OTP | OTP | OTP | OTP | OTP | Flash (reprogrammable) |
| I/O Pins | 20 | 20 | 20 | 20 | 20 | 20 | 20 |
Key Differentiators
- Extended Industrial temperature grade on a baseline OTP die (vs PIC16C55A-20/SP)
- 20 MHz instruction throughput at the lowest cost tier (vs PIC16C55A-04E/SP)
- Drop-in 28-pin SPDIP compatibility with flash-based PIC16F57 successor (vs PIC16F57-I/SP)
Design Notes
PIC16C55A is OTP (One-Time Programmable), not flash. There is no in-circuit reprogramming window - once the programming pin sequence closes, the part cannot be re-flashed. Validate firmware on a PIC16F57 or PIC16C55A JW (windowed) sample before committing to OTP volume orders, and budget for MPLAB PM3 programming tooling at the contract manufacturer.
PIC16C5X baseline parts operate from 3.0V to 6.25V. At 5V with the 20 MHz oscillator, current draw is typically 5-10 mA active and sub-1 uA in sleep. Place a 100 nF ceramic decoupling capacitor as close as possible to the Vdd pin (pin 14) with a short trace to Vss (pin 5) to suppress switching-noise coupling into the internal bandgap reference.
The SPDIP-28 footprint is through-hole and tolerates hand-soldering and IC sockets. Keep the MCLR pull-up resistor (typically 10 kohm) within 5 mm of pin 4 to avoid spurious resets from capacitive coupling. If using an external crystal, route OSC1/OSC2 traces over a continuous ground pour and keep them short to avoid stray pickup on the high-impedance clock input.
Estimated: at 5V Vdd, 20 MHz oscillator, 100% active CPU, the PIC16C55A-20E/SP typically draws about 8-10 mA, dissipating roughly 40-50 mW - no heatsink required even at 125C ambient. However, high source-current loads on multiple I/O pins (e.g., driving 8 LEDs at 20 mA each) add 160 mA per port; verify total package dissipation against the SPDIP-28 thermal resistance of approximately 70 C/W before pushing I/O to the limit.
Compliance Information
PIC16C55A-20E/SP is a through-hole SPDIP part from the legacy PIC16C5X OTP family. Microchip's product page does not surface RoHS/REACH compliance badges for this NRND part; confirm with the manufacturer or distributor before using in RoHS-restricted designs. AEC-Q100 qualification is not claimed - automotive users should validate EMC and temperature performance to their specific module requirements.
