PIC16C56AT-04/SO - 4MHz 8-bit OTP MCU 1.5KB | Microchip SOIC-18
MPN: PIC16C56AT-04/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.61 | $26.10 |
| 100 | $2.18 | $218.00 |
| 500 | $1.93 | $965.00 |
| 1,000 | $1.72 | $1,720.00 |
PIC16C56AT-04/SO Overview
An 8-bit microcontroller (MCU) is a self-contained computing element that integrates a CPU core, non-volatile program memory, working RAM, and programmable I/O peripherals on a single CMOS die. The PIC16C5X family represents one of the earliest reduced-instruction-set computing (RISC) architectures adopted in mainstream microcontrollers, employing a 12-bit-wide instruction word that yields roughly 2:1 code compression versus competing 8-bit CISC architectures in the same era. Within the broader taxonomy, this device sits at the hierarchy: 8-bit MCU -> RISC microcontroller -> microcontroller -> embedded processor -> semiconductor IC.
Key differentiating specifications of the PIC16C56AT-04/SO include its 33 single-word (12-bit) instructions, fully static CMOS design that allows clock rates down to DC, dedicated watchdog timer with on-chip RC oscillator, power-saving SLEEP mode, and wide operating voltage range. The 12-bit instruction width and Harvard bus architecture deliver deterministic throughput of one instruction per two clock cycles, enabling predictable interrupt response suitable for cost-sensitive real-time control loops.
Typical applications include low-cost appliance control, automotive interior lighting (non-safety), simple sensor interfaces, hobby robotics, and replacement of discrete logic in legacy designs. The OTP program memory is ideal for short production runs or prototype deployments where mask-ROM volume economics are not justified. The 4 MHz CPU clock combined with 1K instruction words provides sufficient headroom for state-machine-style controllers in industrial and consumer products.
When designing with this part, designers should note the absence of in-circuit serial programming (ICSP) on early PIC16C5X silicon - code is loaded via a parallel programmer socket prior to solder mounting, or via windowed ceramic packages. The '04' speed grade must not be exceeded; 20 MHz variants use the '-20' suffix. For new designs, the flash-based PIC16F57 family offers modern in-circuit programmability at the cost of changed non-volatile memory technology.
This page consolidates distributor pricing, drop-in alternatives, parametric comparison, and design notes not aggregated on any single manufacturer or distributor page, providing a faster engineering reference than individual datasheet searches.
Drop-in alternatives for PIC16C56AT-04/SO — 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-04/SO (same form factor and footprint) — differing in Core Architecture, Program Memory Type, Watchdog Timer, Mounting Type, Family.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56AT-04I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C56AT-04E/SO
✅ Drop-In✓ In Stock
$1.81 / Unit
View Datasheet →PIC16C56AT-20/SO
✅ Drop-In✓ In Stock
$1.71 / Unit
View Datasheet →PIC16C56A-04I/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.02 / Unit
View Datasheet →PIC16C56A-04/SO
✅ Drop-In✓ In Stock
$1.4 / Unit
View Datasheet →PIC16C56AT-04/SO
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.72 / Unit
View Datasheet →PIC16C56AT-04/SO Maximum Ratings & Electrical Characteristics
| Product Type | 8-bit Microcontroller (MCU) |
| Series | PIC 16C |
| Family | PIC16C5X |
| Core Architecture | RISC, 12-bit instruction word |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM Size | 25 bytes |
| Maximum CPU Frequency | 4 MHz |
| Number of I/O Pins | 12 |
| Number of Instructions | 33 single-word (12-bit) |
| Supply Voltage | 5 V (typical) |
| Operating Temperature | 0C to +70C (Commercial) |
| Package Type | 18-SOIC (7.50 mm body width, 0.295 inch) |
| Mounting Type | Surface Mount (Gull-Wing leads) |
| Watchdog Timer | Yes, on-chip dedicated RC oscillator |
| Power-Saving Modes | SLEEP mode |
| RoHS Status | Non-Compliant (legacy OTP product) |
PIC16C56AT-04/SO Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O port A bit 2 |
| Pin 2 | RA3 — Bidirectional I/O port A bit 3 |
| Pin 3 | RTCC — Real-Time Clock/Counter input or I/O |
| Pin 4 | MCLR — Master Clear (reset) input, active low |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0 — Bidirectional I/O port B bit 0 (interrupt-on-change) |
| Pin 7 | RB1 — Bidirectional I/O port B bit 1 |
| Pin 8 | RB2 — Bidirectional I/O port B bit 2 |
| Pin 9 | RB3 — Bidirectional I/O port B bit 3 |
| Pin 10 | RB4 — Bidirectional I/O port B bit 4 |
| Pin 11 | RB5 — Bidirectional I/O port B bit 5 |
| Pin 12 | RB6 — Bidirectional I/O port B bit 6 |
| Pin 13 | RB7 — Bidirectional I/O port B bit 7 |
| Pin 14 | VDD — Positive supply voltage (+5V) |
| Pin 15 | OSC2 — Oscillator output (crystal/RC/resonator) |
| Pin 16 | OSC1 — Oscillator input (crystal/RC/external clock) |
| Pin 17 | RA0 — Bidirectional I/O port A bit 0 |
| Pin 18 | RA1 — Bidirectional I/O port A bit 1 |
Typical Applications
PIC16C56AT-04/SO is suitable for 6 applications: Low-Cost Appliance Control, Hobby Robotics and Educational Kits, Automotive Interior Lighting, Simple Sensor Interface Modules, Replacement of Discrete Logic (Logic Integration), Remote Control and IR Transmitter/Receiver.
Low-Cost Appliance Control
The PIC16C56AT-04/SO fits low-cost appliance control boards (coffee makers, toasters, simple washing-machine user interfaces) where its 1.5 KB OTP program memory holds the entire state-machine firmware. The 4 MHz CPU at 1 MIPS instruction throughput handles button debouncing, relay sequencing, and LED multiplexing without external logic. The 12 I/O pins directly drive segment displays and sense triac zero-cross signals. The OTP memory is ideal because appliance firmware rarely changes once locked down, and the 18-SOIC package supports automated SMT assembly at high throughput.
Recommended
Hobby Robotics and Educational Kits
The PIC16C56AT-04/SO's 33-instruction RISC architecture and 25-byte RAM make it a classic teaching vehicle for embedded programming courses and hobby robotics projects. At 4 MHz it provides responsive control of DC motors, servos, and sensor arrays via the 12 I/O pins, while the 12-bit instruction word illustrates RISC code-density advantages over 8051-class parts. The 18-SOIC package fits standard 0.1-inch-pitch breakout boards. The OTP memory encourages disciplined firmware development, and the Watchdog timer teaches real-time reliability concepts in laboratory exercises.
Recommended
Automotive Interior Lighting
The PIC16C56AT-04/SO can drive non-safety automotive interior lighting modules (ambient LED strips, vanity mirrors, courtesy lamps) where its 12 I/O pins handle PWM dimming, button inputs, and LIN-bus emulation via software. The commercial temperature grade (0C to +70C) suffices for cabin environments, and the 18-SOIC footprint integrates easily into compact lighting-controller PCBs. The Watchdog timer ensures recovery from automotive electrical transients. Note: safety-critical lighting requires the AEC-Q100 qualified PIC16F series instead.
Recommended
Simple Sensor Interface Modules
The PIC16C56AT-04/SO interfaces low-bandwidth sensors (thermistors, photodiodes, simple switches) to higher-level controllers via UART bit-banging or pulse-width encoding on its 12 I/O pins. At 4 MHz it samples analog channels via the on-chip comparator and computes threshold decisions in firmware, transmitting results to a host MCU. The 25-byte RAM is sufficient for short rolling buffers, and the SLEEP mode reduces quiescent current for battery-powered sensor nodes. The 18-SOIC package suits miniature sensor PCBs.
Recommended
Replacement of Discrete Logic (Logic Integration)
The PIC16C56AT-04/SO replaces dozens of 74-series logic gates in legacy designs by integrating state-machine behavior into firmware, reducing PCB area and BOM cost. The 1.5 KB OTP holds the equivalent of 200+ discrete gates worth of sequencing logic, and the 18-SOIC package replaces DIP-14 or DIP-16 logic packages with the same footprint plus added flexibility. Designers can change behavior via firmware revision rather than PCB rework. This use case is common when modernizing 1980s-1990s industrial controllers.
Recommended
Remote Control and IR Transmitter/Receiver
The PIC16C56AT-04/SO implements consumer remote-control transmitter and receiver firmware thanks to its deterministic interrupt latency (2 clock cycles) and 4 MHz CPU, which accurately generates and decodes IR carrier frequencies (typically 36-40 kHz). The 12 I/O pins drive IR LEDs, read keypads, and indicate status LEDs without external glue logic. The 1.5 KB OTP holds dozens of button-to-code mappings. SLEEP mode drops quiescent current below 1 uA for battery-powered remotes lasting years on a single cell.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56AT-04/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56AT-04I/SO | PIC16C56AT-04E/SO | PIC16C56AT-20/SO | PIC16C56A-04/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC (0.295 inch) | 18-SOIC (0.295 inch) - same | 18-SOIC (0.295 inch) - same | 18-SOIC (0.295 inch) - same | 18-SOIC (0.295 inch) - same |
| Program Memory | 1.5 KB OTP (1K x 12) | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP |
| Maximum CPU Frequency | 4 MHz | 4 MHz | 4 MHz | 20 MHz (5x faster) | 4 MHz |
| RAM Size | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| I/O Pins | 12 | 12 | 12 | 12 | 12 |
| Operating Temperature | 0C to +70C (Commercial) | -40C to +85C (Industrial) | Extended grade | 0C to +70C (Commercial) | 0C to +70C (Commercial) |
| Memory Type | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM | OTP EPROM |
Key Differentiators
- Single-supply 5V operation with 33-instruction RISC core (vs PIC16C55AT-04/SO)
- Commercial-temperature pricing advantage (vs PIC16C56AT-04I/SO)
- Industry-standard 18-SOIC JEDEC MS-013 footprint (vs PIC16C56A-20I/SS (20-pin SSOP))
Design Notes
The PIC16C56AT-04/SO operates from a single +5V supply on VDD (pin 14) with VSS (pin 5) as ground. During SLEEP mode, the on-chip watchdog timer continues running from its dedicated internal RC oscillator, drawing typically 7-15 uA. For battery-powered designs, disable the watchdog via configuration bit if absolute minimum quiescent current is required. Estimated: at 5V VDD and 4 MHz CPU active, typical IDD is approximately 2-5 mA depending on I/O loading and oscillator type.
Place the decoupling capacitor (0.1 uF ceramic) within 5 mm of the VDD pin (14) to suppress noise injected by the CPU core. The MCLR reset pin (4) requires a 10 kohm pull-up resistor to VDD for normal operation; do not leave MCLR floating. The OSC1/OSC2 crystal or ceramic resonator (pins 16/15) should be placed adjacent to the IC with short traces to minimize stray capacitance; ground the oscillator can pin if using a 3-pin ceramic resonator.
Do not confuse PIC16C56 with PIC16F56 - the F suffix indicates flash memory and ICSP support, while the C suffix indicates one-time-programmable EPROM. The PIC16C56AT-04/SO cannot be reprogrammed in-circuit; firmware must be loaded via a parallel programmer before PCB mounting. The 'A' suffix denotes the silicon revision (PIC16C56A) and should not be confused with the lead-free packaging suffix. Programming voltage on the MCLR/VPP pin must reach 13V during parallel programming - verify programmer compatibility.
Compliance Information
RoHS non-compliant per legacy PIC16C5X product family status. Not AEC-Q100 qualified - select automotive-grade PIC16F variants for vehicle applications.
