PIC16C56AT-04E/SO - 8-bit OTP MCU, 4MHz, 1.5KB | Microchip
MPN: PIC16C56AT-04E/SO β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.56 | $25.60 |
| 100 | $2.27 | $227.00 |
| 500 | $2.04 | $1,020.00 |
| 1,000 | $1.81 | $1,810.00 |
PIC16C56AT-04E/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, and peripheral interfaces on one silicon die. The PIC16C5X family belongs to the 8-bit microcontroller taxonomy, sitting beneath broader categories of microcontrollers, embedded processors, and finally integrated circuits. These classic PIC MCUs serve cost-sensitive, deterministic control applications where 12-bit wide instructions deliver 2:1 code compression versus competing 8-bit architectures of the same era.
Key features include an extended operating temperature range of -40C to +125C (the 'E' suffix), 4 MHz maximum clock at 4 MHz crystal/RC oscillator input, 12 I/O pins with high-current sink/source capability, an 8-bit real-time timer/counter, watchdog timer with on-chip RC oscillator, power-on reset, and code protection. The 18-SOIC (0.295 inch / 7.50 mm width) package supports legacy surface-mount designs with reliable hand-soldering and standard IR reflow profiles.
The PIC16C56AT uses an enhanced Harvard architecture with separate program and data buses, allowing simultaneous instruction fetch and data access. Its 33 single-word instructions and 12-bit-wide instruction word simplify compiler output and hand-coded assembly, while the fully static design enables operation down to DC clock speeds for low-power sleep implementations.
Typical applications include appliance control, automotive sub-systems (body electronics, lighting controllers), industrial sensor interfaces, simple motor control, smart card readers, and battery-powered instrument front-ends. The 1.5 KB program memory fits state-machine logic, lookup tables, and small protocol stacks including I2C bit-banging or LIN slave handlers.
When designing with this device, note that the OTP memory cannot be reprogrammed - choose the PIC16F56 flash sibling or PIC16C56A-20/SO windowed ceramic-package variant for development. Decoupling VDD with 0.1 uF close to the pins is mandatory; the MCLR reset pin requires a pull-up for normal operation.
This page synthesizes distributor inventory, parametric alternatives, and practical design notes beyond the manufacturer datasheet, helping engineers source, qualify, and design-in the PIC16C56AT-04E/SO with confidence.
Drop-in alternatives for PIC16C56AT-04E/SO 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 PIC16C56AT-04E/SO (same form factor and footprint) β differing in Package, Timers, I/O Pins, Mounting Type, Program Memory Type.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C56A-04E/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56A-04E/P
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.21 / Unit
View Datasheet βPIC16C55AT-04E/SO
β Drop-Inβ In Stock
$1.67 / Unit
View Datasheet βPIC16C558-04E/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16F56-I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56AT-04E/SO Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Series | PIC16C5X |
| Core Architecture | PIC (8-bit RISC, Harvard) |
| Program Memory | 1.5 KB (1K x 12) OTP/EPROM |
| RAM | 25 x 8 bytes |
| Maximum Clock Frequency | 4 MHz |
| Data Bus Width | 8 bit |
| Instruction Set Word Size | 12 bit |
| I/O Pins | 12 |
| Timers | 1 x 8-bit with WDT |
| Watchdog Timer | Yes (on-chip RC oscillator) |
| Package | 18-SOIC (0.295" / 7.50 mm width) |
| Operating Temperature Range | -40C to +125C (Extended, 'E' suffix) |
| Oscillator Type | External RC / Crystal |
| Program Memory Type | OTP (One-Time Programmable) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
PIC16C56AT-04E/SO Pin Configuration
| Pin 1 | RA2 β Port A bit 2 (bidirectional I/O) |
| Pin 2 | RA3 β Port A bit 3 (bidirectional I/O) |
| Pin 3 | RTCC β Real-Time Clock/Counter input (Schmitt trigger) |
| Pin 4 | MCLR β Master Clear (reset, active low, requires pull-up) |
| Pin 5 | VSS β Ground reference |
| Pin 6 | RB0 β Port B bit 0 (bidirectional I/O) |
| Pin 7 | RB1 β Port B bit 1 (bidirectional I/O) |
| Pin 8 | RB2 β Port B bit 2 (bidirectional I/O) |
| Pin 9 | RB3 β Port B bit 3 (bidirectional I/O) |
| Pin 10 | RB4 β Port B bit 4 (bidirectional I/O) |
| Pin 11 | RB5 β Port B bit 5 (bidirectional I/O) |
| Pin 12 | RB6 β Port B bit 6 (bidirectional I/O) |
| Pin 13 | RB7 β Port B bit 7 (bidirectional I/O) |
| Pin 14 | VSS β Ground reference (second VSS pin) |
| Pin 15 | OSC2 β Oscillator output (crystal/RC) |
| Pin 16 | OSC1 β Oscillator input (crystal/RC) |
| Pin 17 | RC0 β Port C bit 0 (bidirectional I/O) |
| Pin 18 | RC1 β Port C bit 1 (bidirectional I/O) |
Typical Applications
PIC16C56AT-04E/SO is suitable for 6 applications: Appliance Control Front-End, Automotive Body Electronics, Industrial Sensor Interface, Smart Card and RFID Reader, Battery-Powered Instrument Front-End, LED Lighting Controller.
Appliance Control Front-End
The PIC16C56AT-04E/SO fits white-goods appliance controls including dishwasher cycle timers, washing machine user interfaces, and microwave oven keypad handlers. Its 1.5 KB OTP memory holds state-machine code for relay sequencing, LED/LCD multiplexing, and buzzer feedback patterns. The 12 I/O pins directly drive triac optocouplers, scan 4x4 matrix keypads via Charlieplexing, and read rotary encoder inputs. The extended -40C to +125C range survives under-hood or compressor-adjacent mounting where consumer-grade MCUs would fail. Compared with modern Cortex-M0 alternatives, this part costs less than half per unit at production volumes, justifying OTP for one-time-programmed firmware.
Recommended
Automotive Body Electronics
The PIC16C56AT-04E/SO serves automotive body controllers such as interior lighting dimmers, seat-position memory switches, and mirror-adjustment modules. Its 4 MHz core and 12-bit instruction width deliver deterministic control without RTOS overhead, and the -40C to +125C range handles cabin and underhood thermal excursions. The 12 I/O lines read switch matrices, drive MOSFET gates for LED strings, and PWM low-side loads for seat motors. Microchip's automotive-grade product longevity program typically supports the PIC16C5X family for 15+ years, matching vehicle production cycles.
Recommended
Industrial Sensor Interface
The PIC16C56AT-04E/SO excels at industrial sensor signal-conditioning nodes, converting analog or digital sensor outputs to clean protocol frames for PLC backplanes. The 1.5 KB program memory fits calibration tables, linearization curves for thermocouples or RTDs, and Modbus RTU or 4-20 mA loop transmitters. Its 4 MHz clock provides ample bandwidth for bit-banged SPI/I2C to digital sensors like the MCP9808 or ADS1118. The wide operating temperature ensures reliable operation in factory-floor enclosures without derating, and the OTP memory protects against firmware tampering in field-deployed sensor modules.
Recommended
Smart Card and RFID Reader
The PIC16C56AT-04E/SO drives low-cost contactless smart-card readers for access control, transit fare collection, and loyalty terminals. Its deterministic instruction timing handles bit-banged ISO 14443 Type A/B protocols for proximity cards and ISO 15693 for vicinity tags. The 25-byte RAM fits temporary buffers for UID extraction and authentication challenge-response sequences, while the 1.5 KB OTP stores cryptographic look-up tables for proprietary protocols. Compared with 32-bit alternatives, the PIC16C5X core's predictable timing eliminates RTOS jitter in critical reader-to-card handshake windows.
Recommended
Battery-Powered Instrument Front-End
The PIC16C56AT-04E/SO suits handheld instruments like digital multimeters, infrared thermometers, and portable gas detectors where low cost and small footprint outweigh raw compute. Its 4 MHz core and 12 I/O pins drive segment LCDs via charge-pump circuits, read rotary-encoder knobs, and time battery shutoff via watchdog. Compared with more capable PIC16F1xxx parts, the PIC16C56AT-04E/SO delivers production-cost savings below $1.50 USD per unit at 1K quantities - critical for sub-$20 consumer test instruments competing in retail channels.
Recommended
LED Lighting Controller
The PIC16C56AT-04E/SO controls decorative and architectural LED installations including RGB strip drivers, DMX512 slave nodes, and Christmas light sequences. Its 12 I/O pins and hardware timer generate software PWM channels for color mixing and brightness control at up to 8-bit resolution per channel. The 1.5 KB program memory holds pattern tables, fade curves, and DMX address parsing logic. The wide -40C to +125C range supports outdoor IP65-rated fixtures where ambient temperatures swing from winter cold to summer sun exposure.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56AT-04E/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56A-04E/SO | PIC16C55AT-04E/SO | PIC16C558-04E/SO | PIC16F56-I/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same | 18-SOIC - same |
| Program Memory | 1.5 KB OTP | 1.5 KB OTP | 1 KB OTP (-33%) | 2 KB OTP (+33%) | 1.5 KB Flash (reprogrammable) |
| RAM | 25 bytes | 25 bytes | 24 bytes | 68 bytes | 25 bytes |
| Max Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| I/O Pins | 12 | 12 | 12 | 13 | 12 |
| Program Memory Type | OTP | OTP | OTP | OTP | Flash |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +85C |
| Instruction Set Word | 12-bit | 12-bit | 12-bit | 14-bit | 12-bit |
Key Differentiators
- Extended -40C to +125C temperature range (vs PIC16F56-I/SO)
- Lowest unit cost in PIC16C5X family (vs PIC16C558-04E/SO)
- OTP memory protects against firmware tampering (vs PIC16F56-I/SO)
Design Notes
Decouple VDD with a 0.1 uF ceramic capacitor placed within 5 mm of the VDD/VSS pins. The PIC16C5X core draws brief current spikes during instruction fetches; insufficient decoupling causes oscillator jitter and unexpected resets via the brown-out or MCLR paths. For battery-powered designs, add a 10 uF bulk electrolytic or tantalum on the VDD rail to handle inrush when relays or LED strings energize.
Route the crystal/oscillator traces as short as possible, with the load capacitors (typically 15-33 pF for low-speed crystals) placed close to OSC1 and OSC2. Keep oscillator traces away from switching traces and high-current outputs to minimize EMI coupling. If using an external clock source, drive only OSC1 and leave OSC2 floating per datasheet recommendations. The MCLR pin requires a 10 kohm pull-up to VDD - never leave it floating in production designs.
OTP memory cannot be erased or rewritten - verify firmware on a PIC16C56A-20/SO windowed ceramic-package variant or PIC16F56-I/SO Flash sibling before committing to production volume. Configuration bits (watchdog enable, oscillator selection, code protection, MCLR enable) are part of the program memory and must be set correctly - an unprogrammed device defaults to safe but unusable state. I/O pins default to input on power-up; configure TRIS registers before driving outputs.
The PIC16C5X I/O pins have limited sink/source capability (typically 25 mA per pin, 100 mA total). For driving relays, solenoids, or high-current LEDs, use external MOSFETs (2N7002 or similar) or driver ICs (ULN2003A) rather than loading the MCU outputs directly. When reading switch contacts, add 100 nF debounce capacitors in parallel or implement software debounce with a 5-10 ms timer to eliminate contact bounce artifacts.
Compliance Information
RoHS compliant per Microchip product declaration. The 'E' suffix denotes extended -40C to +125C temperature grade, not automotive qualification; AEC-Q100 status not specified on the datasheet. Lead-free and halogen-free per package materials declaration.
