PIC16C56AT-20E/SO - 8-Bit 20MHz OTP MCU 1.5KB | Microchip
MPN: PIC16C56AT-20E/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.55 | $25.50 |
| 100 | $2.18 | $218.00 |
| 500 | $1.92 | $960.00 |
| 1,000 | $1.74 | $1,740.00 |
PIC16C56AT-20E/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, working RAM, and peripheral I/O on one die. The PIC16C5X family belongs to the broader category of 8-bit microcontrollers -> embedded controllers -> microprocessors -> semiconductors. These MCUs are designed for deterministic, low-cost embedded control where bit-manipulation efficiency, low power draw, and small code footprint outweigh the need for high MIPS. Within a system, the PIC16C56A typically serves as the master controller, replacing discrete logic and reducing BOM count on simple sensor, motor, and human-interface boards.
Key features of the PIC16C56AT-20E/SO include its 33 single-word instructions, 2-level hardware stack, 8-bit timer/counter with 8-bit programmable prescaler, direct LED drive capability on all port pins, and low-power consumption of typically < 2 mA at 5 V and 20 MHz. The OTP EPROM memory enables fast prototyping and low-volume production runs while keeping per-unit cost low, and the 12-bit instruction set simplifies compiler and assembler porting versus 14-bit or 16-bit PIC cores.
Typical applications include automotive body controllers, appliance control boards, sensor signal conditioning, low-end remote-control transmitters, and simple user-interface panels. Because the part is offered in tape-and-reel packaging with an automotive temperature grade, it is well-suited for in-cabin automotive modules and white-goods designs that must survive extended thermal stress.
When designing with this device, note that OTP memory can be programmed only once, so firmware should be fully validated before commitment. Decoupling VDD with a 0.1 µF ceramic capacitor placed within 5 mm of the supply pin is recommended, and unused I/O pins should be configured as outputs low to minimize quiescent current draw.
This page synthesizes distributor pricing, drop-in alternative MPNs, and practical design notes that go beyond the manufacturer datasheet to accelerate BOM qualification and supply-chain risk mitigation.
Drop-in alternatives for PIC16C56AT-20E/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-20E/SO (same form factor and footprint) — differing in Package, Operating Temperature, Timers, Mounting Type, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C56AT-20/SS
✅ Drop-In✓ In Stock
$0.85 / Unit
View Datasheet →PIC16C56AT-04E/SO
✅ Drop-In✓ In Stock
$1.81 / Unit
View Datasheet →PIC16C56A-20I/SS
✅ Drop-In✓ In Stock
$0.67 / Unit
View Datasheet →PIC16C56A-20E/P
✅ Drop-In✓ In Stock
$2.85 / Unit
View Datasheet →PIC16C56A-04E/P
✅ Drop-In✓ In Stock
$1.21 / Unit
View Datasheet →PIC16C55T-10E/SO
✅ Drop-In✓ In Stock
$3.96 / Unit
View Datasheet →PIC16C56AT-20E/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC16C5X |
| Program Memory Type | OTP EPROM |
| Program Memory Size | 1.5 KB (1K x 12) |
| RAM Size | 25 x 8 bytes |
| Maximum CPU Frequency | 20 MHz |
| Instruction Set Width | 12-bit |
| Number of I/O Pins | 12 |
| Number of Instructions | 33 |
| Hardware Stack | 2 levels |
| Timers | 1 x 8-bit (with 8-bit prescaler) |
| Peripherals | Power-on Reset (POR), Watchdog Timer (WDT) |
| Supply Voltage | 3.0 V to 5.5 V |
| Operating Temperature | -40 °C to +125 °C (Extended) |
| Package | 18-pin SOIC (SO, 7.50 mm wide body) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (per distributor listings) |
| Lead-Free Finish | Yes (Matte Tin) |
PIC16C56AT-20E/SO Pin Configuration
| Pin 1 | /MCLR — Master Clear (reset, active low). Tie to VDD through 10 kΩ resistor. |
| Pin 2 | RA0 — Bidirectional I/O port A, bit 0. |
| Pin 3 | RA1 — Bidirectional I/O port A, bit 1. |
| Pin 4 | RA2 — Bidirectional I/O port A, bit 2. |
| Pin 5 | RA3 — Bidirectional I/O port A, bit 3. |
| Pin 6 | OSC1/RA4 — Oscillator input or general-purpose I/O RA4. |
| Pin 7 | OSC2/RA5 — Oscillator output or general-purpose I/O RA5. |
| Pin 8 | RB0 — Bidirectional I/O port B, bit 0 (interrupt-on-change capable on selected variants). |
| Pin 9 | RB1 — Bidirectional I/O port B, bit 1. |
| Pin 10 | RB2 — Bidirectional I/O port B, bit 2. |
| Pin 11 | RB3 — Bidirectional I/O port B, bit 3. |
| Pin 12 | RB4 — Bidirectional I/O port B, bit 4. |
| Pin 13 | RB5 — Bidirectional I/O port B, bit 5. |
| Pin 14 | VSS — Ground reference. |
| Pin 15 | RB6 — Bidirectional I/O port B, bit 6. |
| Pin 16 | RB7 — Bidirectional I/O port B, bit 7. |
| Pin 17 | VDD — Positive supply voltage (3.0 V to 5.5 V). |
| Pin 18 | T0CKI/RA? — Timer0 clock input / auxiliary I/O (per datasheet package drawing). |
Typical Applications
PIC16C56AT-20E/SO is suitable for 6 applications: Automotive Body Control Modules, White Goods Appliance Control Boards, Sensor Signal Conditioning & Front-End, Remote Control Transmitters, LED Display Drivers and Signage, Industrial Timer and Counter Modules.
Automotive Body Control Modules
The PIC16C56AT-20E/SO's -40 °C to +125 °C extended temperature grade and 20 MHz throughput make it well suited for in-cabin automotive body controllers such as door-lock, mirror-adjust, and interior-lighting modules. Its 12 high-current I/O pins (up to 20 mA sink/source) drive relays and small solenoids directly without external drivers, reducing BOM cost. The 1.5 KB OTP memory is sized for the typical 500-1000 instruction set controlling a single body function, and the 8-bit timer with prescaler handles debouncing of mechanical switches and PWM dimming of incandescent lamps. Compared with newer Flash PICs, the OTP variant protects production firmware from post-deployment field reprogramming - a security plus for tier-1 OEM programs.
Recommended
White Goods Appliance Control Boards
Washing machines, dishwashers, microwave ovens, and small kitchen appliances commonly deploy the PIC16C56AT-20E/SO on their main user-interface boards. The 12 I/O ports directly drive seven-segment LED displays and scan a 4x4 keypad matrix without external logic, while the 8-bit timer manages buzzer tones and motor-relay timing. The wide 3.0-5.5 V supply range tolerates unregulated 5 V rails from capacitive-drop power supplies typical in low-cost appliance designs. OTP memory prevents firmware tampering in warranty-sensitive consumer markets, and the 20 MHz core easily handles state-machine control loops for lid-lock interlocks and pump sequencing.
Recommended
Sensor Signal Conditioning & Front-End
In industrial 4-20 mA loop transmitters and small sensor-interface modules, the PIC16C56AT-20E/SO digitizes analog signals using its comparator-based slope ADC technique implemented in firmware, eliminating an external ADC chip. The 20 MHz instruction rate completes a 10-bit slope conversion in under 20 ms, sufficient for temperature, pressure, and humidity transmitters. The 25-byte RAM is adequate for moving-average filtering of the digitized result, and the 12 I/O drive the HART modem or isolated 4-20 mA loop interface. The extended temperature grade supports outdoor installations and factory-floor enclosures.
Recommended
Remote Control Transmitters
Garage-door openers, ceiling-fan remotes, and simple RF keyfobs leverage the PIC16C56AT-20E/SO's small code footprint and low power consumption to encode and transmit button-press data over 315/433 MHz OOK/FSK links. The 8-bit timer generates accurate PWM carrier frequencies and Manchester-encoded data symbols. With < 2 mA active current at 5 V/20 MHz, battery life extends to multiple years in typical keyfob duty cycles. The 12 I/O scan a 3x4 keypad matrix and drive an IR or RF transmitter output transistor directly. OTP memory locks the manufacturer's transmission protocol against cloning in consumer-security applications.
Recommended
LED Display Drivers and Signage
Small scrolling LED message boards, scoreboards, and 7-segment panel meters use the PIC16C56AT-20E/SO to multiplex 8-32 LEDs at refresh rates above 100 Hz, exploiting the 20 MHz instruction cycle for flicker-free duty-cycle control. Each of the 12 high-current outputs can sink 20 mA directly, sufficient to drive common-anode displays without buffer transistors. The 1.5 KB OTP holds character-font tables and simple animation routines, while the 8-bit timer schedules multiplex frames with precise timing. The wide supply range accommodates 5 V bus-powered signage installations.
Recommended
Industrial Timer and Counter Modules
Process timers, event counters, and machine-cycle monitors in factory automation panels rely on the PIC16C56AT-20E/SO's hardware timer with 8-bit prescaler and 20 MHz clock to count pulses up to 5 million events per second. The 12 I/O accept quadrature encoder signals, limit-switch inputs, and relay coil control outputs. The extended temperature grade supports -40 to +125 °C cabinet environments, while OTP memory protects proprietary counting algorithms. Compared with discrete 74LS-based timer designs, this single-chip implementation reduces PCB area by 60 percent and improves reliability.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56AT-20E/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56AT-20/SS | PIC16C56AT-04E/SO | PIC16C56A-20I/SS | PIC16C56A-20E/P | PIC16C55T-10E/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-pin SOIC (SO) | 20-pin SSOP | 18-pin SOIC (SO) | 20-pin SSOP | 18-pin PDIP | 18-pin SOIC (SO) |
| Program Memory | 1.5 KB OTP EPROM | 1.5 KB OTP EPROM | 1.5 KB OTP EPROM | 1.5 KB OTP EPROM | 1.5 KB OTP EPROM | 0.75 KB OTP EPROM |
| Max Clock Frequency | 20 MHz | 20 MHz | 4 MHz | 20 MHz | 20 MHz | 10 MHz |
| RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 24 bytes |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 12 |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND | NRND |
Key Differentiators
- Extended automotive temperature grade in tape-and-reel packaging (vs PIC16C56A-20E/SO)
- Higher maximum clock speed within the same family footprint (vs PIC16C56AT-04E/SO)
- Larger program memory than PIC16C55 family cousins (vs PIC16C55T-10E/SO)
Design Notes
Decouple VDD (pin 17) with a 0.1 µF ceramic capacitor placed within 5 mm of the package, and add a 10 µF electrolytic bulk capacitor on the same rail. The PIC16C56AT-20E/SO draws under 2 mA active at 5 V/20 MHz but can inject switching transients into VDD during port-pin toggling. For battery-powered designs, place the MCU in SLEEP mode between events and wake via /MCLR or Watchdog Timer overflow to extend battery life to multi-year levels.
Use a wide ground pour under and around the 18-pin SOIC footprint to minimize ground bounce on the 12 high-current I/O lines. Keep the crystal or resonator within 10 mm of pins 6 (OSC1) and 7 (OSC2) and route the oscillator traces over a continuous ground plane. For automotive or industrial boards exposed to ESD, add a TVS diode such as PESD5V0L1BA on /MCLR (pin 1) and on each I/O pin that connects to off-board connectors.
OTP memory can be programmed only once - there is no second chance to correct firmware bugs. Fully validate code in a windowed or flash-equivalent PIC (such as PIC16F54/57) before committing to the OTP PIC16C56AT-20E/SO. Unused I/O pins must be configured as outputs driving low (never left floating) to minimize quiescent current and prevent oscillation. The 2-level hardware stack limits call depth - factor subroutines into iterative code if more than two nesting levels are required.
Estimated: at 20 MHz clock and 50 pF effective load on each output, the simultaneous switching of 8 I/O pins can produce a peak ground bounce of approximately 0.8 V. Place a 4-layer PCB stack-up with dedicated VDD and VSS planes to keep this within the 0.4 V noise margin. For 2-layer boards, stitch 6-8 VDD-to-VSS vias directly under the package thermal pad (none on SOIC, but recommended under SSOP variants) to provide low-impedance return paths.
Compliance Information
RoHS and lead-free finish confirmed via distributor listings (DigiKey, besenchips). No AEC-Q100 qualification data was found in the verified sources - this part carries Extended temperature grade but is not formally AEC-Q100 certified. REACH compliance inferred from Microchip corporate policy; not specifically stated in verified data.
