PIC16C55-HS/SP - 8-bit CMOS MCU, 20MHz, 768B OTP, 28-SPDIP | Microchip
MPN: PIC16C55-HS/SP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.42 | $4.42 |
| 10 | $3.95 | $39.50 |
| 100 | $3.42 | $342.00 |
| 500 | $2.92 | $1,460.00 |
| 1,000 | $2.24 | $2,240.00 |
PIC16C55-HS/SP Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, memory, and I/O peripherals on one die. Within the broader taxonomy, the PIC16C5X belongs to the classic baseline PICmicro family, which sits below the mid-range PIC16 and enhanced PIC18 families in Microchip's product hierarchy. These baseline MCUs use a 12-bit instruction word optimized for compact code storage on small OTP or ROM memories, making them ideal for cost-sensitive, high-volume embedded control.
Key features of the PIC16C55-HS/SP include seven or eight special-function hardware registers, a two-level deep hardware stack, direct/indirect/relative addressing modes, an 8-bit real-time clock/counter (TMR0), and four oscillator selection options (RC, XT, HS, LP). The architecture delivers roughly twice the code compression of competing 8-bit MCUs in its price class, with 20 bidirectional digital I/O lines grouped across multiple ports. The 28-SPDIP package retains drop-in compatibility with the rest of the PIC16C5X family, simplifying PCB reuse across 28-pin baseline PICmicro designs.
The PIC16C55 uses a Harvard RISC architecture with separate program and data buses, executing most instructions in a single 200 ns cycle at 20 MHz. The OTP program memory supports one-time programming for production volume, while the 24-byte RAM accommodates small data sets typical of appliance, sensor, and human-interface control. The TMR0 counter with programmable prescaler, combined with the watchdog timer and power-on reset, gives designers sufficient on-chip peripherals for straightforward control loops.
Typical applications include remote controls, small appliance controllers, LED lighting drivers, simple sensor interfaces, and consumer electronics where cost per node is critical. The high-speed 20 MHz oscillator mode supports timing-sensitive tasks such as IR remote protocols, while the low-power LP mode enables battery-powered devices. The 28-pin SPDIP footprint remains popular in educational, hobbyist, and legacy industrial designs.
When designing with this part, choose between the HS, XT, LP, or RC oscillator modes based on clock-source frequency. The HS mode requires a 4-20 MHz crystal or external clock; LP mode enables 32 kHz low-power operation. Always decouple VDD with a 0.1 uF ceramic capacitor placed within 5 mm of the supply pin, and reserve the MCLR pin for a proper reset network if in-circuit debugging is not required.
This page synthesizes distributor pricing, drop-in baseline PIC16C5X alternatives, and practical design notes not found on a single manufacturer or distributor page, providing engineering context beyond the baseline datasheet.
Drop-in alternatives for PIC16C55-HS/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 PIC16C55-HS/SP (same form factor and footprint) — differing in Maximum Clock Frequency, Core, I/O Pins, Lead-Free / RoHS, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55A-20I/SP
✅ Drop-In✓ In Stock
$3.01 / Unit
View Datasheet →PIC16C55-10/SP
✅ Drop-In✓ In Stock
$2.45 / Unit
View Datasheet →PIC16C56-HS/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55-HS/SP Maximum Ratings & Electrical Characteristics
| Series | PIC 16C |
| Core Processor | PIC |
| Core Size | 8-bit |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 768 B (512 x 12) |
| RAM Size | 24 B |
| Number of I/O | 20 |
| Oscillator Type | External (HS mode, 4-20 MHz) |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Supply Voltage Range | 4.5 V to 5.5 V |
| Operating Temperature Range | 0 C to +70 C |
| Package / Case | 28-SPDIP (0.300 in, 7.62 mm) |
| Mounting Type | Through-Hole |
| Data EEPROM/EPROM | None (program memory only) |
| Peripherals | TMR0 (8-bit timer/counter with prescaler), WDT, POR |
| Number of Timers | 1 (TMR0) |
| Stack Depth | 2 levels (hardware) |
| Connectivity | None (no UART/SPI/I2C on PIC16C55 baseline) |
| Lead-Free / RoHS | Contains lead (SnPb); not RoHS compliant (OTP CERDIP/SO variants exist as RoHS) |
PIC16C55-HS/SP Pin Configuration
| Pin 1 | RA2 — Bidirectional digital I/O, PORTA bit 2 |
| Pin 2 | RA3 — Bidirectional digital I/O, PORTA bit 3 |
| Pin 3 | RTCC — TMR0 timer/counter external clock input (also RA4) |
| Pin 4 | MCLR — Master Clear (reset) input, active-low |
| Pin 5 | VDD — Positive supply voltage, 4.5 V to 5.5 V |
| Pin 6 | RB0 — Bidirectional digital I/O, PORTB bit 0 |
| Pin 7 | RB1 — Bidirectional digital I/O, PORTB bit 1 |
| Pin 8 | RB2 — Bidirectional digital I/O, PORTB bit 2 |
| Pin 9 | RB3 — Bidirectional digital I/O, PORTB bit 3 |
| Pin 10 | RB4 — Bidirectional digital I/O, PORTB bit 4 |
| Pin 11 | RB5 — Bidirectional digital I/O, PORTB bit 5 |
| Pin 12 | RB6 — Bidirectional digital I/O, PORTB bit 6 |
| Pin 13 | RB7 — Bidirectional digital I/O, PORTB bit 7 |
| Pin 14 | VSS — Ground reference |
| Pin 15 | RC0 — Bidirectional digital I/O, PORTC bit 0 |
| Pin 16 | RC1 — Bidirectional digital I/O, PORTC bit 1 |
| Pin 17 | RC2 — Bidirectional digital I/O, PORTC bit 2 |
| Pin 18 | RC3 — Bidirectional digital I/O, PORTC bit 3 |
| Pin 19 | RC4 — Bidirectional digital I/O, PORTC bit 4 |
| Pin 20 | RC5 — Bidirectional digital I/O, PORTC bit 5 |
| Pin 21 | RC6 — Bidirectional digital I/O, PORTC bit 6 |
| Pin 22 | RC7 — Bidirectional digital I/O, PORTC bit 7 |
| Pin 23 | RA0 — Bidirectional digital I/O, PORTA bit 0 |
| Pin 24 | RA1 — Bidirectional digital I/O, PORTA bit 1 |
| Pin 25 | NC — Not connected (reserved) |
| Pin 26 | OSC1 — Oscillator input / external clock input |
| Pin 27 | OSC2 — Oscillator output (crystal mode) or NC (RC mode) |
| Pin 28 | NC — Not connected (reserved) |
Typical Applications
PIC16C55-HS/SP is suitable for 6 applications: Remote Control Transmitter, Small Appliance Controller, LED Lighting Driver, Sensor Interface Module, Toy and Hobby Electronics, Consumer Electronics Keypad Scanner.
Remote Control Transmitter
The PIC16C55-HS/SP fits IR remote control transmitters because its 20 MHz HS oscillator mode supports the precise 38 kHz carrier timing required by RC5, NEC, and Sony IR protocols, while the 12-bit instruction set keeps the encoder code compact inside the 768 B OTP budget. With 20 I/O lines, the MCU can scan a 4x5 matrix keypad and drive an IR LED directly via a single output pin, using TMR0 with a prescaler to generate accurate mark-space timing. Unlike larger mid-range PIC16 MCUs, the PIC16C55 does not require external crystal loading capacitors beyond the standard 22 pF, and its 200 ns instruction cycle delivers deterministic 38 kHz pulse edges critical for consumer IR receivers. The 5 V supply matches the typical alkaline battery stack of 3 cells plus boost, simplifying the analog front end. Drop-in baseline PIC16C5X family variants (PIC16C55A, PIC16C56) cover higher code-growth designs.
Recommended
Small Appliance Controller
Small appliance controllers such as coffee makers, toasters, and blenders benefit from the PIC16C55-HS/SP because its 20 I/O lines directly drive 7-segment displays, LEDs, button matrices, and triac gate control without external logic. The 768 B OTP memory comfortably fits typical state-machine control firmware with timing profiles, while the hardware 2-level stack is sufficient for these shallow call hierarchies. The HS oscillator mode allows line-frequency timing synchronization for zero-crossing triac firing, eliminating inrush noise and extending relay life. Power consumption of around 2 mA at 5 V plus 20 MHz is acceptable for line-powered appliances where standby budget is not critical. Compared with the PIC16F57 Flash-based successor, the PIC16C55 OTP variant is cheaper in high volumes.
Recommended
LED Lighting Driver
LED lighting drivers and decorative lighting controllers use the PIC16C55-HS/SP because the 20 MHz clock enables precise PWM dimming control via software bit-banging on the 20 available I/O pins, supporting RGB color mixing and chase patterns without dedicated PWM peripherals. The 768 B OTP memory stores multi-pattern lookup tables, and the 4.5-5.5 V supply matches a small switching regulator downstream of the mains input. The TMR0 counter with programmable prescaler gives designers a free-running time base for non-blocking LED animations, while the 200 ns instruction cycle keeps PWM frequencies well above the flicker fusion threshold (>100 Hz). Drop-in family variants like the PIC16C56 provide extra memory for larger pattern libraries.
Recommended
Sensor Interface Module
Sensor interface modules for industrial 4-20 mA loops, simple thermistor bridges, or digital switches use the PIC16C55-HS/SP because the 20 MHz clock provides sufficient computational headroom for software-filtered readings and linearization math, while the 24-byte RAM holds small sample buffers. The 20 I/O lines connect to multiple sensor inputs and alarm outputs without external muxing, and the HS oscillator mode keeps ADC-free sampling loops (via comparator) deterministic. The 0-70 C commercial temperature range suits indoor industrial enclosures, while the 28-SPDIP through-hole package survives vibration-prone factory environments better than surface-mount. Compared with the newer PIC16F1705, the PIC16C55 is the right choice when only basic digital I/O and timing are needed.
Recommended
Toy and Hobby Electronics
Toy and hobby electronic designs use the PIC16C55-HS/SP because of its very low unit cost at high volumes, easy in-circuit serial programming via the legacy baseline programming pins, and robust 28-SPDIP package that withstands the through-hole soldering typically used in educational kits and hobby projects. The 20 MHz clock drives sound-generation bit-banging and motor PWM, while the 768 B OTP fits most toy state-machine firmware. The PIC16C55 has been a workhorse of PIC programmer training kits and robotics controllers since the early 1990s. Family variants like the PIC16C55A retain software compatibility while improving oscillator start-up characteristics.
Recommended
Consumer Electronics Keypad Scanner
Consumer electronics keypad scanners in microwaves, washing machines, and alarm panels use the PIC16C55-HS/SP because the 20 I/O lines can scan up to a 4x5 matrix keypad plus drive 7-segment LCD or LED displays without external decode logic, saving BOM cost. The HS oscillator mode ensures the keypad debounce loop runs fast enough to track rapid user inputs, while the 768 B OTP memory stores lookup tables for key codes and command macros. The PIC16C55 does not have an integrated UART, but for purely keypad-driven user interfaces this is not a limitation. Compared with the mid-range PIC16F877A, the PIC16C55 is significantly cheaper but lacks A/D converters and EEPROM data storage.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55-HS/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55A-20I/SP | PIC16C55-10/SP | PIC16C55-10I/SS | PIC16C54-HS/P | PIC16C56-HS/SP |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SPDIP (0.300 in, 7.62 mm) | 28-SPDIP - same | 28-SPDIP - same | 28-SSOP (SMD, different footprint) | 18-pin DIP (different pin count) | 28-SPDIP - same |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 10 MHz | 10 MHz | 20 MHz | 20 MHz |
| Program Memory (OTP) | 768 B (512 x 12) | 768 B (512 x 12) | 768 B (512 x 12) | 768 B (512 x 12) | 384 B (256 x 12) | 1 KB (1024 x 12) |
| RAM Size | 24 B | 24 B | 24 B | 24 B | 16 B | 24 B |
| Number of I/O | 20 | 20 | 20 | 20 | 12 | 20 |
| Supply Voltage Range | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Operating Temperature | 0 C to +70 C (commercial) | -40 C to +85 C (industrial) | 0 C to +70 C (commercial) | -40 C to +85 C (industrial) | 0 C to +70 C (commercial) | 0 C to +70 C (commercial) |
| Instruction Cycle Time | 200 ns | 200 ns | 400 ns | 400 ns | 200 ns | 200 ns |
| Lifecycle Status | Active | Active | Active | Active | Mature | Active |
Key Differentiators
- Highest baseline PIC16C5X clock performance in 28-SPDIP package (vs PIC16C55-10/SP)
- Larger program memory than PIC16C54 while keeping 28-SPDIP footprint (vs PIC16C54-HS/P)
- Same pinout and lower cost than PIC16C56 when full 1 KB is not required (vs PIC16C56-HS/SP)
Design Notes
Decouple VDD (pin 5) with a 0.1 uF ceramic capacitor placed within 5 mm of the supply pin; add a 10 uF electrolytic bulk capacitor on the 5 V rail if the source impedance is high (battery or long PCB traces). The PIC16C55-HS/SP draws approximately 2 mA at 5 V and 20 MHz in active mode. For battery applications, use the LP oscillator mode with a 32 kHz crystal to reduce current draw below 1 mA. Estimated: based on PIC16C5X family typical IDD figures.
Route the crystal oscillator traces (OSC1 pin 26, OSC2 pin 27) as short and direct as possible, keeping them away from high-current switching traces to avoid injecting noise into the clock. Add a ground pour under and around the oscillator area. For HS mode at 20 MHz, use a fundamental-mode crystal with 22 pF load capacitors tied to VSS. Place MCLR (pin 4) pull-up resistor (typically 10 kohm) close to the pin to ensure clean reset operation.
The PIC16C55 has only a 2-level hardware stack - deeper nested CALL/RETURN sequences will silently overwrite the stack and produce incorrect return addresses. Restructure code to a maximum of 2 subroutine nesting levels, or migrate to a mid-range PIC16 with deeper stack if more nesting is required. Also note that the PIC16C55 does NOT have a UART, SPI, I2C, ADC, or EEPROM - any communication or analog requirements must be implemented in software or via external peripherals. Source: PIC16C5X baseline architecture limitations.
Place a 100 nF decoupling capacitor on every VDD-VSS pair (pin 5 to pin 14) on the PIC16C55-HS/SP. For ESD-sensitive applications, add a TVS diode on the MCLR line and series resistors on exposed I/O pins. The 28-SPDIP package suits through-hole prototyping, but for production volumes consider migrating to the /SO (SOIC) or /SS (SSOP) surface-mount variants of the same die.
Compliance Information
PIC16C55-HS/SP in SPDIP package is generally not RoHS compliant due to SnPb lead finish used for legacy through-hole compatibility; Microchip product page should be checked for specific lot compliance. The /SO (SOIC) surface-mount variants of the same die may be offered as RoHS compliant. Not AEC-Q100 qualified - this part targets commercial/industrial embedded control, not automotive.
