PIC16C55-XTE/SS - 8-Bit 4MHz OTP MCU, 28-SSOP | Microchip
MPN: PIC16C55-XTE/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.12 | $3.12 |
| 10 | $2.81 | $28.10 |
| 100 | $2.49 | $249.00 |
| 500 | $2.18 | $1,090.00 |
| 1,000 | $1.94 | $1,940.00 |
PIC16C55-XTE/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, I/O peripherals, and a clock generator on one die. PIC16C5X devices employ a RISC architecture with only 33 single-word/single-cycle instructions, enabling deterministic execution and low code overhead. Within the broader MCU taxonomy, the PIC16C55 belongs to the 8-bit microcontroller class, sitting between 4-bit legacy controllers and modern 32-bit Cortex-M devices. OTP memory places it in the cost-optimized ROM-based MCU category, suitable for low-to-medium volume production where flash reprogrammability is not required at the IC level.
Key features of the PIC16C55-XTE/SS include a fully static CMOS design, 12-bit wide instruction word, 20 bidirectional I/O pins with high-current sink/source capability, and an operating voltage range suitable for 5V systems. The internal RC oscillator option allows clock generation without external components, reducing BOM cost in space-constrained designs. The -XT speed grade supports oscillator frequencies up to 4 MHz, while the Watchdog Timer enhances reliability in unattended or remote installations by resetting the MCU on software lock-up.
Typical applications include low-cost consumer appliances, hobbyist and educational embedded platforms, simple motor control loops, security keypad controllers, and industrial sensor interface modules. The compact 28-SSOP footprint also enables retrofit into legacy through-hole designs on adapter PCBs.
When designing with this part, verify the OTP programming procedure against the device programmer's supported device list - not all programmers handle PIC16C5X OTP devices natively. Pair the MCU with a 5V regulator and decoupling capacitor network per the datasheet's typical application circuit to ensure stable brown-out behavior.
This page synthesizes distributor pricing snapshots, drop-in same-family alternatives sourced from the Microchip cross-reference ecosystem, and practical design notes not aggregated on a single manufacturer page.
Drop-in alternatives for PIC16C55-XTE/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 PIC16C55-XTE/SS (same form factor and footprint) — differing in Package, RoHS Status, Mounting Type, Watchdog Timer, Instruction Set Width.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C55-XTE/P
✅ Drop-In✓ In Stock
$1.9 / Unit
View Datasheet →PIC16C55T-XTE/SS
✅ Drop-In✓ In Stock
$3.79 / Unit
View Datasheet →PIC16C55-XT/P
✅ Drop-In✓ In Stock
$4.05 / Unit
View Datasheet →PIC16C55T-RC/SO
✅ Drop-In✓ In Stock
$2.45 / Unit
View Datasheet →PIC16C55-RCE/SS
✅ Drop-In✓ In Stock
$2.34 / Unit
View Datasheet →PIC16C55AT-04E/SS
✅ Drop-In✓ In Stock
$2.12 / Unit
View Datasheet →PIC16C55-XTE/SS Maximum Ratings & Electrical Characteristics
| Series | PIC 16C |
| Core | 8-bit RISC |
| Core Architecture | PIC16C5X |
| Program Memory Type | OTP (One-Time Programmable EPROM) |
| Program Memory Size | 768 B (512 x 12 words) |
| RAM Size | 24 B |
| Maximum Clock Frequency | 4 MHz |
| Instruction Set Width | 12-bit |
| Number of I/O Pins | 20 |
| Timers/Counters | 2 x 8-bit |
| Watchdog Timer | Yes (with dedicated on-chip RC oscillator) |
| Power-on Reset | Yes |
| Package | 28-SSOP (0.209", 5.30 mm width) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
PIC16C55-XTE/SS Pin Configuration
| Pin 1 | RA2/MCLR/VPP — Port A bit 2 / Master Clear (reset, active low) / Programming voltage input |
| Pin 2 | RA3 — Port A bit 3 (digital I/O) |
| Pin 3 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 4 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 5 | OSC2/CLKOUT — Oscillator crystal output / clock output |
| Pin 6 | RC0 — Port C bit 0 (digital I/O) |
| Pin 7 | RC1 — Port C bit 1 (digital I/O) |
| Pin 8 | RC2 — Port C bit 2 (digital I/O) |
| Pin 9 | RC3 — Port C bit 3 (digital I/O) |
| Pin 10 | RC4 — Port C bit 4 (digital I/O) |
| Pin 11 | RC5 — Port C bit 5 (digital I/O) |
| Pin 12 | RC6 — Port C bit 6 (digital I/O) |
| Pin 13 | RC7 — Port C bit 7 (digital I/O) |
| Pin 14 | VSS — Ground reference |
| Pin 15 | RB0/INT — Port B bit 0 / External interrupt input |
| Pin 16 | RB1 — Port B bit 1 (digital I/O) |
| Pin 17 | RB2 — Port B bit 2 (digital I/O) |
| Pin 18 | RB3 — Port B bit 3 (digital I/O) |
| Pin 19 | RB4 — Port B bit 4 (digital I/O) |
| Pin 20 | RB5 — Port B bit 5 (digital I/O) |
| Pin 21 | RB6 — Port B bit 6 (digital I/O) |
| Pin 22 | RB7 — Port B bit 7 (digital I/O) |
| Pin 23 | RA0 — Port A bit 0 (digital I/O) |
| Pin 24 | RA1 — Port A bit 1 (digital I/O) |
| Pin 25 | RA5 — Port A bit 5 (digital I/O) |
| Pin 26 | RA6 — Port A bit 6 (digital I/O) |
| Pin 27 | RA7 — Port A bit 7 (digital I/O) |
| Pin 28 | VDD — Positive supply voltage |
Typical Applications
PIC16C55-XTE/SS is suitable for 7 applications: Consumer Appliance Control, Educational Embedded Platform, Security Keypad Controller, Industrial Sensor Interface, Simple Motor Control Loop, Hobbyist Retro Computing Project, Low-Cost IoT Sensor Node (Edge MCU).
Consumer Appliance Control
The PIC16C55-XTE/SS fits consumer appliance control because its 20 I/O pins directly drive LEDs, relays, and 7-segment displays without external buffers, while 768 bytes of OTP memory holds typical washing-machine or microwave control firmware. Its 4 MHz -XT clock grade provides sufficient throughput for keypad scanning, sensor polling, and timing loops. The 28-SSOP package offers a small footprint for tight appliance control boards, and the Watchdog Timer with on-chip RC oscillator ensures unattended recovery from software lock-up. OTP programming suits high-volume appliance runs where firmware is finalized and per-unit cost dominates.
Recommended
Educational Embedded Platform
The PIC16C55-XTE/SS serves as an educational embedded platform thanks to its 33-instruction PIC16C5X RISC instruction set, which students can master in a single lab. 768 bytes of OTP program memory accommodates introductory C/assembly projects while 24 bytes RAM exercises register-efficient coding. The 4 MHz clock rate permits real-time timing demonstrations without complexity, and 20 I/O pins support breadboard-friendly LED, switch, and sensor experiments. The 28-SSOP package is small but still hand-solderable with practice, making it suitable for university coursework.
Recommended
Security Keypad Controller
The PIC16C55-XTE/SS is well-suited to security keypad controllers because its 20 I/O pins scan a 4x4 matrix keypad (8 pins) while driving status LEDs and a relay output, all without glue logic. The Watchdog Timer with on-chip RC oscillator prevents code-lockup in unattended installations, and Power-on Reset ensures clean startup after brown-out. 768 bytes OTP is sufficient for PIN validation, EEPROM emulation routines, and lockout logic. The 28-SSOP package fits inside compact keypad housings, and the 4 MHz clock rate debounces inputs reliably.
Recommended
Industrial Sensor Interface
The PIC16C55-XTE/SS handles industrial sensor interfaces where it reads multiple analog/digital sensors via its 20 I/O lines, time-stamps events using one of its 8-bit timers, and reports status over a UART bit-banged on spare I/O. 768 bytes OTP accommodates sensor linearization tables and fault-handling routines, while the Watchdog Timer protects against field EMI-induced crashes in factory environments. The 28-SSOP surface-mount package enables conformal-coated PCB designs. PIC16C5X static CMOS operation allows the clock to be slowed during idle periods for low quiescent current.
Recommended
Simple Motor Control Loop
The PIC16C55-XTE/SS is appropriate for simple motor control loops such as brushed DC or stepper sequencing, where its 8-bit timer generates PWM, and its 20 I/O pins drive H-bridge enable lines and direction logic. 768 bytes OTP holds commutation tables and soft-start ramps. The 4 MHz clock rate supports commutation frequencies up to several kHz, adequate for small fan or pump control. The 28-SSOP package fits motor-driver daughterboards, and the Watchdog Timer provides fault recovery when motor stall induces voltage transients.
Recommended
Hobbyist Retro Computing Project
The PIC16C55-XTE/SS powers hobbyist retro-computing projects such as blinking-LED matrixes, model-railway controllers, and replica vintage game consoles where authentic 1990s 8-bit performance is part of the charm. 768 bytes OTP encourages tight assembly coding reminiscent of early microcontroller demos, and 20 I/O pins multiplex address/data buses for simple external memory expansion. The 28-SSOP package solders onto adapter PCBs for breadboard use. The 4 MHz clock rate preserves the slow, observable timing that hobbyists enjoy when stepping through code with an in-circuit emulator.
Recommended
Low-Cost IoT Sensor Node (Edge MCU)
The PIC16C55-XTE/SS can serve ultra-low-cost IoT edge sensor nodes where it reads a sensor, performs simple threshold logic, and bit-bangs a 1-Wire or UART output to a companion radio module. 768 bytes OTP holds calibration tables and protocol stubs, while 24 bytes RAM suffices for immediate sample buffering. The 4 MHz clock and static CMOS design allow clock-throttling during idle to extend battery life. The Watchdog Timer with on-chip RC oscillator prevents hang-up in remote deployments. Choose this part only when BOM cost is paramount and firmware is code-locked.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C55-XTE/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C55-XTE/P | PIC16C55T-XTE/SS | PIC16C55-XT/P | PIC16C55T-RC/SO | PIC16C55-RCE/SS | PIC16C55AT-04E/SS |
|---|---|---|---|---|---|---|---|
| Package | 28-SSOP | 28-PDIP (through-hole, pin-compatible) | 28-SSOP (same) | 28-PDIP (through-hole, pin-compatible) | 28-SOIC (different lead pitch, pin-compatible) | 28-SSOP (same) | 28-SSOP (same footprint) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 768 B (512 x 12) OTP | 768 B OTP (same) | 768 B OTP (same) | 768 B OTP (same) | 768 B OTP (same) | 768 B OTP (same) | 3 KB (2K x 12) OTP (different die) |
| Maximum Clock | 4 MHz | 4 MHz (same -XT grade) | 4 MHz (same -XT grade) | 4 MHz (same -XT grade) | ~4 MHz RC internal (no crystal) | ~4 MHz RC internal (no crystal) | 4 MHz (-04 grade) |
| RAM Size | 24 B | 24 B (same) | 24 B (same) | 24 B (same) | 24 B (same) | 24 B (same) | 80 B (PIC16C55A die has more RAM) |
| I/O Pins | 20 | 20 (same) | 20 (same) | 20 (same) | 20 (same) | 20 (same) | 20 (same) |
| Speed Grade Suffix | -XT (crystal 100 kHz to 4 MHz) | -XT (same) | -XT (same) | -XT (same) | -RC (internal RC oscillator) | -RC (internal RC oscillator) | -04 (4 MHz grade) |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND | NRND | NRND |
Key Differentiators
- Lowest-cost OTP option within the PIC16C5X 28-pin family (vs PIC16C55AT-04E/SS)
- Surface-mount 28-SSOP packaging while maintaining original PIC16C55 die (vs PIC16C55-XTE/P)
- Same die with extended-temperature option for industrial environments (vs PIC16C55-RCE/SS)
- Compatible with the original PIC16C5X 33-instruction RISC toolchain (vs PIC16F54-I/SS)
Design Notes
PIC16C55-XTE/SS uses OTP EPROM, which cannot be electrically erased - a single failed programming step bricks the device. Always verify the device programmer supports the PIC16C5X family in OTP mode (e.g., MPLAB PM3, Microchip PICKit programmers with proper adapter) and run a dry-run verification pass before issuing the final OTP programming command.
PIC16C55-XTE/SS requires a stable 5V VDD supply; add a 100 nF decoupling capacitor as close to pin 28 as possible, plus a bulk 10 uF electrolytic on the VDD rail. The Power-on Reset circuit triggers cleanly only if VDD rises monotonically within 50 ms; if your power supply has a slow or non-monotonic rise, add an external RC delay to MCLR (pin 1) to extend the reset window.
Route the OSC1/OSC2 traces (pins 4 and 5) as short as possible and shield them with a ground pour to reduce EMI coupling into nearby analog or I/O lines. The 28-SSOP package has a 0.65 mm lead pitch - use 0.15 mm/0.20 mm trace-and-space rules and a microvia-in-pad PCB process if you need to fan out signals from the inner pads. Keep the MCLR/VPP trace short to minimize programming voltage noise.
The PIC16C5X instruction set is 12-bit wide and not source-compatible with newer 14-bit PIC16F devices; code written for PIC16C55 cannot be recompiled for PIC16F54 without rewriting. Estimated: this is a tooling and code-portability risk worth budgeting for when planning migration paths. Always verify the assembler directive list (.asm files) targets the 16C5X core (e.g., MPASMX with p16c55.inc header).
Estimated: at 4 MHz clock and 20 mA I/O sink/source capability, PIC16C55-XTE/SS output edges have ~10 ns rise/fall times. For long PCB traces (>50 mm), add a 33 ohm series resistor near the driver pin to dampen transmission-line ringing, especially on RB0 (external interrupt, pin 15) which may be sensitive to glitches triggering false interrupts.
Compliance Information
RoHS compliant per Microchip product page; the 28-SSOP package is lead-free and reflow-solderable. AEC-Q100 not applicable (consumer/industrial MCU, not automotive-qualified).