PIC16C56A-20I/SS - 8-Bit OTP MCU, 1.5KB, 20MHz | Microchip
MPN: PIC16C56A-20I/SS β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.93 | $0.93 |
| 10 | $0.85 | $8.50 |
| 100 | $0.78 | $78.00 |
| 500 | $0.72 | $360.00 |
| 1,000 | $0.67 | $670.00 |
PIC16C56A-20I/SS Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, volatile data memory, and peripheral interfaces. The PIC16C5X family is one of the earliest Microchip PIC architectures - a fully static, EPROM/ROM-based CMOS RISC core featuring a two-level hardware stack, direct/indirect/relative addressing, and seven or eight special-function hardware registers. As an OTP device, the PIC16C56A is factory-programmed or user-programmed once and cannot be erased, which positions it between mask-ROM (PIC16C56) and windowed-EPROM (PIC16C56/JW) variants for low-volume production.
Key differentiating features include the 8-bit Timer0 with a programmable prescaler, 12 I/O pins, a wide 2.5V-6.25V operating range, and an industrial temperature grade of -40C to +85C. The 20 MHz oscillator mode is denoted by the -20 speed suffix, while the /SS suffix confirms the 5.30 mm body 20-pin SSOP surface-mount package with gull-wing leads, ideal for compact PCB designs where DIP footprint is too large.
Architecturally, the device uses a Harvard-style memory map with separate program and data buses, executes single-cycle instructions except for program branches, and provides a hardware stack two levels deep - sufficient for simple subroutine nesting. The PIC16C5X is fully static, allowing the clock to be stopped for low-power sleep states.
Typical applications include appliance control, LED driver sequencers, simple sensor interface boards, low-cost consumer toys, and replacement of discrete logic in legacy designs. Its small SSOP footprint makes it attractive for space-constrained handheld products and disposable medical devices where per-unit cost dominates BOM decisions.
When designing, ensure the oscillator configuration matches the application: RC mode for lowest cost, XT for standard 4 MHz crystals, HS for 20 MHz operation. OTP parts require one-time programming via Microchip's PRO MATE II or compatible device programmer; consider the flash-based PIC16F54 drop-in if in-field firmware updates are needed later.
This page synthesizes distributor stock and pricing, drop-in alternative MPNs with parametric match scores, and practical design notes not consolidated on the manufacturer product page.
Drop-in alternatives for PIC16C56A-20I/SS β 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-20I/SS (same form factor and footprint) β differing in Package, Program Memory Size, Program Memory Type, RoHS Status, Core Architecture.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C56A-20I/P
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56A-20I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C55A-20I/SS
β Drop-Inβ In Stock
$1.04 / Unit
View Datasheet βPIC16F54-I/SS
β Drop-Inπ Reference alternative (not in catalog)
PIC16F57-I/SS
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56A-04I/SS
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56A-20I/SS Maximum Ratings & Electrical Characteristics
| Family | PIC16C5X |
| Core Architecture | 8-bit RISC PIC |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 1.5 KB (1K x 12 words) |
| Data RAM | 25 bytes |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns at 20 MHz |
| Operating Voltage Range | 2.5 V to 6.25 V |
| I/O Pins | 12 |
| Timers | 1 x 8-bit (TMR0 with prescaler) |
| Hardware Stack | 2 levels |
| Instruction Word Width | 12 bits |
| Data Path Width | 8 bits |
| Package | 20-pin SSOP (5.30 mm body) |
| Mounting Type | Surface Mount (Gull Wing) |
| Operating Temperature | -40C to +85C (Industrial) |
| Temperature Grade | Industrial |
| MSL Level | 1 |
| RoHS Status | Compliant |
PIC16C56A-20I/SS Pin Configuration
| Pin 1 | RA0 β Bidirectional I/O port A bit 0 |
| Pin 2 | RA1 β Bidirectional I/O port A bit 1 |
| Pin 3 | RA2 β Bidirectional I/O port A bit 2 |
| Pin 4 | RA3 β Bidirectional I/O port A bit 3 |
| Pin 5 | RA4/T0CKI β Port A bit 4 / Timer0 clock input |
| Pin 6 | /MCLR β Master Clear (reset) input, active low |
| Pin 7 | VSS β Ground reference |
| Pin 8 | OSC1 β Oscillator input / external clock input |
| Pin 9 | OSC2 β Oscillator output (crystal mode) |
| Pin 10 | RC0 β Bidirectional I/O port C bit 0 |
| Pin 11 | RC1 β Bidirectional I/O port C bit 1 |
| Pin 12 | RC2 β Bidirectional I/O port C bit 2 |
| Pin 13 | RC3 β Bidirectional I/O port C bit 3 |
| Pin 14 | RC4 β Bidirectional I/O port C bit 4 |
| Pin 15 | RC5 β Bidirectional I/O port C bit 5 |
| Pin 16 | RC6 β Bidirectional I/O port C bit 6 |
| Pin 17 | RC7 β Bidirectional I/O port C bit 7 |
| Pin 18 | RB0/INT β Port B bit 0 / external interrupt input |
| Pin 19 | RB1 β Bidirectional I/O port B bit 1 |
| Pin 20 | VDD β Positive supply voltage |
Typical Applications
PIC16C56A-20I/SS is suitable for 6 applications: Appliance Control (Washing Machines, Microwaves, Fans), LED Lighting Sequencers and Sign Controllers, Consumer Toy and Hobby Electronics, Industrial Sensor Interface Boards, Replacement of Discrete 74HC Logic, Automotive Aftermarket Accessories (Non-Safety).
Appliance Control (Washing Machines, Microwaves, Fans)
The PIC16C56A-20I/SS is well-suited for appliance control boards that require deterministic RISC execution without firmware field updates. Its 1.5 KB OTP memory accommodates state-machine control code for motor sequencing, button de-bouncing, and LED indicator timing; the 20 MHz instruction throughput handles 200 ns cycle loops for real-time sensor polling. The industrial -40C to +85C rating covers kitchen and laundry environments where temperature swings are common. Compared to modern 32-bit MCUs, the PIC16C56A consumes less PCB area in 20-pin SSOP and saves BOM cost in white-goods volumes exceeding 100k units per year.
Recommended
LED Lighting Sequencers and Sign Controllers
For LED chasers, marquee controllers, and channel-letter sign drivers, the PIC16C56A-20I/SS provides 12 I/O pins to multiplex 8-12 LED rows or columns with software PWM. The 8-bit Timer0 with prescaler generates precise blink rates without CPU overhead, while the 20 MHz clock supports high refresh rates up to several kHz to avoid visible flicker. The 2.5V-6.25V supply range aligns with battery packs (2x AA through 4x AA) and 5V regulated adapters, removing the need for a separate LDO in low-cost sign modules.
Recommended
Consumer Toy and Hobby Electronics
Toy-grade products with fixed-behavior firmware favor the PIC16C56A-20I/SS OTP architecture where low unit cost matters more than firmware flexibility. The 20-pin SSOP package fits inside handheld enclosures, and the simple PIC16C5X instruction set keeps firmware development accessible to non-RTOS programming models. Battery-powered toys benefit from the device's fully static design - the oscillator can be halted in sleep mode to extend battery life. Per-unit cost at $0.67 (1000-piece) is competitive against discrete 74HC logic implementations.
Recommended
Industrial Sensor Interface Boards
Sensor hubs reading 4-12 switches, thermistors, or simple analog inputs through an external ADC benefit from the PIC16C56A-20I/SS's 12 I/O pins and 20 MHz execution. The wide 2.5V-6.25V supply tolerates 24V industrial buses after external regulation, and the -40C to +85C industrial temperature grade handles factory-floor environments. The hardware stack supports one level of interrupt-driven subroutine nesting, sufficient for periodic sensor polling loops with watchdog refresh.
Recommended
Replacement of Discrete 74HC Logic
Designers replacing multi-chip 74HC00-series glue logic with a PIC16C56A-20I/SS consolidate state machines into one 20-pin SSOP device, reducing PCB area and assembly cost. The RISC core can implement complex sequencing that would require dozens of discrete gates, while the 12 I/O pins map directly to the signals previously driven by 74HC595 shift registers, 74LS123 monostables, and 74HC161 counters. The -40C to +85C rating matches industrial logic IC specifications.
Recommended
Automotive Aftermarket Accessories (Non-Safety)
Non-safety automotive aftermarket products such as LED accent drivers, switch panels, and gauge illuminators can use the PIC16C56A-20I/SS where AEC-Q100 qualification is not required. The -40C to +85C industrial temperature grade covers cabin environments, and the wide supply range accommodates 12V automotive rails after external regulation. Designers should add external TVS protection on VDD and MCLR for the harsh automotive electrical environment; for safety-critical or AEC-Q100-required designs, the PIC16F57-I/SS or PIC16F1938 should be substituted.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56A-20I/SS β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56A-20I/P | PIC16C56A-20I/SO | PIC16C55A-20I/SS | PIC16F54-I/SS | PIC16F57-I/SS | PIC16C56A-04I/SS |
|---|---|---|---|---|---|---|---|
| Package | 20-pin SSOP | 20-pin PDIP (different package) | 20-pin SOIC (different package) | 20-pin SSOP (same package) | 20-pin SSOP (same package) | 20-pin SSOP (same package) | 20-pin SSOP (same package) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP EPROM (1.5 KB) | OTP EPROM (1.5 KB) | OTP EPROM (1.5 KB) | OTP EPROM (768 words) | Flash (512 words) | Flash (3 KB) | OTP EPROM (1.5 KB) |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 4 MHz |
| RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 72 bytes | 25 bytes |
| Operating Voltage | 2.5 V to 6.25 V | 2.5 V to 6.25 V | 2.5 V to 6.25 V | 2.5 V to 6.25 V | 2.0 V to 5.5 V | 2.0 V to 5.5 V | 2.5 V to 6.25 V |
| Temperature Grade | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 20 | 12 |
| Reprogrammable | No (OTP) | No (OTP) | No (OTP) | No (OTP) | Yes (Flash) | Yes (Flash) | No (OTP) |
| Approximate Unit Price (1000 qty) | $0.67 | $0.72 | $0.70 | $0.65 | $0.85 | $1.10 | $0.62 |
Key Differentiators
- Industrial temperature grade with OTP cost advantage over Flash parts (vs PIC16F54-I/SS)
- 1.5 KB OTP program memory versus 768 words on PIC16C55A (vs PIC16C55A-20I/SS)
- Direct same-family upgrade path with flash reprogrammability (vs PIC16F57-I/SS)
Design Notes
The PIC16C56A-20I/SS operates from 2.5V to 6.25V. Add a 100 nF ceramic decoupling capacitor as close to VDD (pin 20) as possible, plus a 10 uF bulk capacitor on the same supply rail. The /MCLR pin (pin 6) requires a 10 kohm pull-up to VDD; if not used, connect /MCLR directly to VDD. For battery applications, the fully static design allows the oscillator to be stopped in sleep mode, reducing current consumption to a few microamps.
Place the decoupling capacitor within 3 mm of VDD, and keep the OSC1/OSC2 traces short (under 10 mm) to avoid oscillator instability. For HS mode at 20 MHz, use a crystal with 20 pF load capacitance and place the load capacitors close to the OSC pins. The 20-pin SSOP has a 0.65 mm pin pitch - keep trace width under 0.20 mm and use a 0.30 mm via-in-pad design for the GND pad underneath the package if thermal relief is needed.
The PIC16C56A-20I/SS uses 12-bit instructions but has only a 2-level hardware stack - recursive subroutines deeper than 2 levels will silently overflow. Initialize all GPIO ports via the TRISA and TRISC registers immediately after reset; PORTA defaults to analog-comparator input on some PIC16C5X variants and can cause unexpected behavior if not configured. OTP parts can be programmed only once - validate firmware on a PIC16F54-I/SS or PIC16C56/JW (windowed EPROM) prototype before committing to PIC16C56A-20I/SS production orders.
OTP devices require high-voltage (typically 13V) programming on the /MCLR pin. Use Microchip's PRO MATE II or PICkit 3 with the appropriate programming socket adapter for the 20-pin SSOP package. Programming time is typically 1-2 seconds per device. For prototypes and small batches, the PIC16F54-I/SS Flash variant avoids the OTP one-shot limitation at the cost of a higher unit price.
Compliance Information
RoHS compliant per Microchip product page. Not AEC-Q100 qualified - not suitable for automotive safety-critical applications. Lead-free and halogen-free per Microchip environmental certification.
