PIC16C56A-20/SS - 8-Bit 20MHz OTP MCU 1.5KB | Microchip
MPN: PIC16C56A-20/SS ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.1 | $3.10 |
| 10 | $2.79 | $27.90 |
| 100 | $2.48 | $248.00 |
| 500 | $2.21 | $1,105.00 |
| 1,000 | $1.97 | $1,970.00 |
PIC16C56A-20/SS Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, working RAM, and I/O peripherals on one die. PIC16C5X microcontrollers belong to the original baseline PIC architecture with 12-bit-wide instructions, 8-bit-wide data paths, and a two-level deep hardware stack; they sit at the base of Microchip's PIC hierarchy (PIC16C5X -> baseline PIC -> PICmicro -> 8-bit MCU -> microcontroller -> semiconductor IC) and offer 2:1 code compression versus competing 8-bit devices in their class. The 16C56A variant uses OTP EPROM rather than mask ROM or flash, which simplifies low-volume programming while maintaining a non-volatile program image.
Key features include 12 I/O pins, an 8-bit real-time clock/counter (TMR0), direct/indirect/relative addressing modes for both data and instructions, seven or eight special-function hardware registers, and a wide operating voltage range of 3.0 V to 5.5 V. The PIC16C56A-20/SS variant is rated for 20 MHz operation across the industrial 0C to +70C range. The SSOP-20 (5.30 mm body) package keeps the footprint compact while supporting surface-mount reflow assembly.
Typical applications include low-cost consumer appliances, simple sensor interfaces, motor-control front-ends, LED drivers, and white-goods control boards where deterministic baseline-PIC code density is favored over modern peripherals. The OTP memory, two-level stack, and minimal RAM footprint make this part best suited for fixed-function, ROM-replacement designs rather than application-rich platforms.
When designing with this part, plan code size carefully: 1K x 12 of program memory is only enough for modest state-machine logic, and the two-level hardware stack restricts nested subroutine depth. The PIC16C56A-20/SS does not include an in-system debugger or EEPROM, so consider the newer PIC16F series if your firmware must evolve in the field.
This page synthesizes distributor pricing, drop-in PIC16C5X alternatives, and practical design notes not found on a single manufacturer page, helping engineers and buyers evaluate the part side-by-side with modernized flash-based PIC16F equivalents.
Drop-in alternatives for PIC16C56A-20/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 PIC16C56A-20/SS (same form factor and footprint) — differing in Core Architecture, Package, Timers, Operating Temperature, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56A-20E/SS
✅ Drop-In✓ In Stock
$0.94 / Unit
View Datasheet →PIC16C56A-20I/SS
✅ Drop-In✓ In Stock
$0.67 / Unit
View Datasheet →PIC16C56A-04/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C55A-20/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56AT-20/SS
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.85 / Unit
View Datasheet →PIC16F54-I/SS
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56A-20/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C5X baseline 8-bit |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM | 25 bytes |
| Data EEPROM | None |
| Maximum Clock Frequency | 20 MHz |
| Instruction Width | 12-bit |
| Data Bus Width | 8-bit |
| I/O Pins | 12 |
| Timers | 1 x 8-bit (TMR0) |
| Hardware Stack | 2-level |
| Supply Voltage | 3.0 V to 5.5 V |
| Operating Temperature | 0C to +70C (commercial) |
| Package | SSOP-20 (5.30 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
PIC16C56A-20/SS Pin Configuration
| Pin 1 | RA0 — PORTA bit 0 (bidirectional I/O) |
| Pin 2 | RA1 — PORTA bit 1 (bidirectional I/O) |
| Pin 3 | RA2 — PORTA bit 2 (bidirectional I/O) |
| Pin 4 | RA3 — PORTA bit 3 (bidirectional I/O) |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 6 | RB0/INT — PORTB bit 0 / external interrupt input |
| Pin 7 | RB1 — PORTB bit 1 (bidirectional I/O) |
| Pin 8 | RB2 — PORTB bit 2 (bidirectional I/O) |
| Pin 9 | RB3 — PORTB bit 3 (bidirectional I/O) |
| Pin 10 | RB4 — PORTB bit 4 (bidirectional I/O) |
| Pin 11 | RB5 — PORTB bit 5 (bidirectional I/O) |
| Pin 12 | RB6 — PORTB bit 6 (bidirectional I/O) |
| Pin 13 | RB7 — PORTB bit 7 (bidirectional I/O) |
| Pin 14 | VDD — Positive supply voltage (3.0 V to 5.5 V) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / clock out |
| Pin 16 | OSC1/CLKIN — Oscillator input / external clock in |
| Pin 17 | MCLR/VPP — Master clear reset / programming voltage input |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | VSS — Ground reference |
Typical Applications
PIC16C56A-20/SS is suitable for 6 applications: White Goods and Appliance Control, Low-Cost Sensor Interface Boards, LED Display and Lighting Controllers, Remote Control and IR Transmitter Boards, Toy and Hobby Electronics, Industrial Control Replacement Boards.
White Goods and Appliance Control
The PIC16C56A-20/SS is well suited to white-goods appliance control boards where the baseline PIC16C5X instruction set delivers compact, deterministic firmware for state-machine controllers. With 1.5 KB OTP program memory and a 5 MIPS instruction throughput at 20 MHz, it can run washing-machine timers, microwave user-interface scans, and refrigerator defrost cycles without external logic. The 12 I/O pins drive multiplexed 7-segment displays and keypad matrices directly, eliminating external latches. Compared to flash PIC16F parts, the OTP memory prevents unauthorized firmware cloning, an advantage in cost-sensitive consumer appliances shipped in high volume.
Recommended
Low-Cost Sensor Interface Boards
In simple sensor-interface designs such as thermistor readout boards, smoke detector signal chains, or PIR motion sensor modules, the PIC16C56A-20/SS provides enough processing power at very low cost. The 8-bit TMR0 timer handles periodic sampling, and the 12 I/O drive LED indicators or relay outputs directly. At 20 MHz the part completes analog-to-digital conversion sequences in tens of microseconds using software-only ADC techniques. The wide 3.0 V to 5.5 V supply range accommodates both 3.3 V and 5 V sensor rails. The OTP EPROM program memory is a benefit when the firmware is finalized and anti-cloning protection is desired.
Recommended
LED Display and Lighting Controllers
LED chaser lights, decorative lighting strips, and signage controllers often run on baseline PIC16C5X MCUs because the 5 MIPS throughput is sufficient for bit-banged PWM and the SSOP-20 footprint fits inside compact lamp bases. The PIC16C56A-20/SS can multiplex 7-segment or matrix LED displays using its 12 I/O pins with software-only scan, avoiding external drivers. The OTP memory prevents end users from copying custom chase patterns. The 20 MHz clock rate drives clean PWM dimming at frequencies above the audible band, eliminating flicker in residential and architectural lighting applications.
Recommended
Remote Control and IR Transmitter Boards
The PIC16C56A-20/SS is a classic choice for IR remote-control transmitters in TV, set-top-box, and audio-system remotes. With 1.5 KB OTP program memory, the device can store hundreds of IR protocol command codes, and the 20 MHz throughput generates accurate 38 kHz carrier frequencies using the TMR0 timer. The 12 I/O drive a keypad matrix of up to 16 keys while leaving pins for IR LED output and status indicators. The OTP memory prevents firmware cloning in aftermarket remote markets, and the SSOP-20 footprint fits inside slim remote-control enclosures.
Recommended
Toy and Hobby Electronics
Mass-market toys and hobby electronics benefit from the PIC16C56A-20/SS combination of low unit cost, compact SSOP-20 packaging, and deterministic baseline-PIC code density. Toy manufacturers favor OTP EPROM because it prevents firmware copying by competitors while keeping per-unit cost low. The 5 MIPS throughput at 20 MHz runs sound effects, motor drivers, and servo sequences with precise timing, and the 12 I/O drive LEDs, motors, and audio outputs without external glue logic. Compared with PIC16F-series alternatives, the OTP memory also shortens assembly line programming time.
Recommended
Industrial Control Replacement Boards
The PIC16C56A-20/SS is commonly used as a drop-in replacement on legacy industrial control boards where the original baseline PIC16C5X was specified. With 1.5 KB program memory and a 5 MIPS throughput, it handles relay sequencing, contact-debounce logic, and simple proportional control loops. The SSOP-20 footprint matches the original PIC16C55 and PIC16C56 layouts, allowing direct PCB swap. Although the device is NRND, it remains a viable choice for sustaining existing production lines, and Microchip's continued support of the PIC16C5X family ensures long-term availability for repair and refurbishment channels.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56A-20/SS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56A-20E/SS | PIC16C56A-20I/SS | PIC16C56A-04/SS | PIC16C55A-20/SS | PIC16F54-I/SS |
|---|---|---|---|---|---|---|
| Package | SSOP-20 | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same | SSOP-20 - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | ||
| Program Memory | 1.5 KB OTP EPROM | 0.75 KB OTP EPROM | 0.75 KB Flash | |||
| Maximum Clock | 20 MHz | 4 MHz | 20 MHz | |||
| Temperature Range | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +85C (industrial) | |||
| Program Memory Type | OTP EPROM | OTP EPROM (extended temp) | Flash (re-programmable) | |||
| RAM | 25 bytes | 25 bytes | 25 bytes | |||
| I/O Pins | 12 | 12 | 12 |
Key Differentiators
- Widest commercial-temperature 20 MHz baseline PIC with OTP EPROM in SSOP-20 (vs PIC16C56A-04/SS)
- Larger program memory than closest baseline sibling (vs PIC16C55A-20/SS)
- Lower-cost commercial-temperature OTP option versus flash-based alternative (vs PIC16F54-I/SS)
Design Notes
At 20 MHz the PIC16C56A-20/SS draws approximately 5 mA active current at 5 V. For battery-powered designs, the -04 speed grade variant (PIC16C56A-04/SS) draws 1-2 mA at 4 MHz and is a viable drop-in if your timing budget allows. Always include a 100 nF decoupling capacitor close to VDD (pin 14) and a 10 uF bulk capacitor on the supply rail; the baseline PIC16C5X is sensitive to VDD droop during MCLR reset transitions.
Keep the OSC1/OSC2 traces short and shield them with a ground pour to prevent radiated EMI. The PIC16C56A-20/SS uses a 20 MHz fundamental crystal or ceramic resonator; place the load capacitors (typically 15-33 pF) within 5 mm of the oscillator pins. MCLR (pin 17) requires a 10 kohm pull-up to VDD for normal operation and must never be left floating; connect a 100 nF capacitor from MCLR to ground for noise immunity.
The PIC16C56A-20/SS has only a 2-level hardware stack, so deeply nested subroutine calls will overwrite the return address and crash the firmware. Avoid recursion or call chains deeper than two levels, and prefer in-line code for hot paths. OTP EPROM parts can be programmed only once - if you need to iterate during development, use a PIC16F54-I/SS or a windowed PIC16C56A/JW (UV-erasable) on the engineering bench.
Compliance Information
RoHS/REACH/lead-free status not confirmed in the verified web data - [DATA_NEEDED] for these parameters. Not AEC-Q100 qualified (industrial-grade part).
