PIC16C56AT-20/SS - 8-bit OTP MCU, 1.5KB, 12 I/O, 20MHz | Microchip
MPN: PIC16C56AT-20/SS β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.21 | $1.21 |
| 10 | $1.15 | $11.50 |
| 100 | $1.05 | $105.00 |
| 500 | $0.95 | $475.00 |
| 1,000 | $0.85 | $850.00 |
PIC16C56AT-20/SS Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and configurable I/O peripherals onto one silicon die. Within the semiconductor hierarchy, the PIC16C5x sits below modern 32-bit Cortex-M parts and above simple logic ICs, serving as a low-cost, deterministic, ultra-low-power embedded controller. OTP memory means the program is written once and cannot be electrically erased, which lowers per-unit cost versus flash-based MCUs while still supporting in-circuit programming at production.
Key features of this part include the PIC RISC architecture with 33 single-word/single-cycle instructions (12-bit wide), 2:1 code compression versus competitive 8-bit MCUs, a hardware 8-bit timer/counter with optional prescaler, watchdog timer for reliability, Power-on Reset, brown-out detection, and a wide commercial operating temperature range. The 12 I/O pins can each drive or sink up to 25mA, enabling direct LED or relay drive without external buffers.
Typical applications include low-cost consumer appliance control, simple sensor interfaces, battery-powered remote controls, LED lighting controllers, smoke-detector logic boards, and industrial timers. Its deterministic instruction timing and small footprint also make it useful in legacy system upgrades where a proven 8-bit baseline MCU is required.
When designing with this device, plan the OTP programming step into the production line - the 'A' suffix indicates an automotive-qualified temperature grade, while the 'T' suffix denotes tape-and-reel packaging. Decoupling the VDD pin with a 100nF ceramic capacitor placed within 5mm of the package is strongly recommended for noise immunity.
Drop-in alternatives for PIC16C56AT-20/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 PIC16C56AT-20/SS (same form factor and footprint) β differing in Package, Program Memory Size, Program Memory Type, Core Architecture, Timers.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16C56AT-04E/SS
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16C56A-20I/SS
β Drop-Inβ In Stock
$0.67 / Unit
View Datasheet βPIC16C56AT-20I/SS
β Drop-Inπ Reference alternative (not in catalog)
PIC16C56AT-04/SS
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16F54-I/SS
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
PIC16C56AT-20/SS Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 1.5 KB (1K x 12) |
| Data RAM | 25 bytes |
| CPU Speed | 20 MHz |
| Supply Voltage | 4.5 V to 5.5 V |
| I/O Pins | 12 |
| Timers | 1 x 8-bit with prescaler |
| Watchdog Timer | Yes |
| Instruction Set | 33 single-word instructions, 12-bit wide |
| Package | 20-pin SSOP |
| Mounting Type | Surface Mount |
| Operating Temperature | 0C to +70C (commercial) |
| I/O Sink/Source Current | 25 mA per pin |
| RoHS Status | Compliant |
PIC16C56AT-20/SS Pin Configuration
| Pin 1 | RA2 β Bidirectional I/O pin |
| Pin 2 | RA3 β Bidirectional I/O pin |
| Pin 3 | RA4/T0CKI β Bidirectional I/O / Timer0 clock input |
| Pin 4 | MCLR/VPP β Master Clear (reset) / programming voltage input |
| Pin 5 | VSS β Ground reference |
| Pin 6 | RB0/INT β Bidirectional I/O / external interrupt |
| Pin 7 | RB1 β Bidirectional I/O pin |
| Pin 8 | RB2 β Bidirectional I/O pin |
| Pin 9 | RB3 β Bidirectional I/O pin |
| Pin 10 | RB4 β Bidirectional I/O pin |
| Pin 11 | RB5 β Bidirectional I/O pin |
| Pin 12 | RB6 β Bidirectional I/O pin |
| Pin 13 | RB7 β Bidirectional I/O pin |
| Pin 14 | VDD β Positive supply voltage (4.5V to 5.5V) |
| Pin 15 | OSC2/CLKOUT β Oscillator output / clock output |
| Pin 16 | OSC1/CLKIN β Oscillator input / external clock input |
| Pin 17 | RA0 β Bidirectional I/O pin |
| Pin 18 | RA1 β Bidirectional I/O pin |
| Pin 19 | RA5 β Bidirectional I/O pin |
| Pin 20 | NC β Not connected (per datasheet package pinout for SSOP-20 variant) |
Typical Applications
PIC16C56AT-20/SS is suitable for 6 applications: Consumer Appliance Control, Battery-Powered Remote Controls, Industrial Timer and Counter Modules, LED Lighting and Signage Controllers, Sensor Interface and Signal Conditioning, Smoke Detector and Safety Logic Boards.
Consumer Appliance Control
The PIC16C56AT-20/SS is well-matched to consumer appliance control boards such as coffee makers, microwave ovens, and small kitchen devices. Its 1.5KB OTP program memory holds the appliance state machine, button-debounce logic, and timing routines without external flash, while 25 bytes of RAM tracks mode flags and timer counts. The 20MHz PIC RISC core runs a full instruction in 200ns, easily handling 50/60Hz line-frequency timing and PWM beep generation. Each of the 12 GPIO pins can source or sink 25mA, enabling direct drive of LED indicators, optotriac couplers for triac firing, and piezo buzzers without external transistors. The 20-pin SSOP package fits into the small PCB real estate typical of appliance mainboards, and the commercial 0C to +70C temperature grade covers the kitchen environment. For cost-sensitive high-volume builds, the OTP memory eliminates the need for a separate EEPROM or external flash, lowering the BOM by typically 0.10 to 0.30 USD versus an equivalent flash-MCU solution.
Recommended
Battery-Powered Remote Controls
Remote controls for TVs, set-top boxes, garage-door openers, and toys benefit from the PIC16C56AT-20/SS's low sleep current and 4.5V to 5.5V supply range compatible with two or three alkaline cells. The PIC16C5x baseline core's small instruction set (33 opcodes) keeps firmware under 1.5KB while the 25-byte RAM is sufficient to debounce a 4x4 keypad and manage IR transmit state. The integrated 8-bit timer/counter with prescaler handles accurate 38kHz carrier generation for IR transmission without burdening the main loop. Twelve GPIO pins provide ample capacity for keypad scanning and LED feedback. The PIC's deterministic instruction timing means worst-case interrupt latency is one instruction cycle, which is acceptable for IR protocol generation. Designers should use the watchdog timer to recover from brown-out events when battery voltage sags during IR LED pulse transmission.
Recommended
Industrial Timer and Counter Modules
Industrial timer modules, conveyor-belt counters, and process-tick logic boards use the PIC16C56AT-20/SS as a deterministic 8-bit controller. The 20MHz clock drives the on-chip 8-bit timer/counter with prescaler, supporting accurate time bases from microseconds to seconds. Twelve GPIO pins can drive seven-segment displays via external drivers, accept quadrature encoder signals, or sink relay coils through optocouplers. The integrated Power-on Reset and watchdog timer provide the field reliability required in unattended industrial cabinets. The 20-pin SSOP package is well-suited to conformal-coated industrial PCBs. For factory-floor deployment, the PIC16C56A-20I/SS variant extends the operating temperature to -40C to +85C without any PCB change. The OTP memory's one-time programmability reduces firmware tampering in distributed equipment, an advantage over flash-based MCUs.
Recommended
LED Lighting and Signage Controllers
LED strip controllers, decorative lighting sequencers, and small channel-letter signs use the PIC16C56AT-20/SS to drive 12 GPIO outputs in multiplexed patterns. Each pin's 25mA sink rating can directly drive a single low-current LED or the base of an external MOSFET for high-current channels. The 20MHz instruction cycle supports bit-banged protocols such as WS2812 addressable LEDs at modest channel counts, or pure PWM-free chase patterns for simpler strips. The 1.5KB OTP fits lighting state machines and pattern tables comfortably. Surface-mount SSOP-20 assembly suits high-volume lighting-fixture production lines using standard SMT pick-and-place. The commercial temperature grade covers indoor residential and retail installations. For outdoor signs requiring -40C operation, select the PIC16C56A-20I/SS variant in the same footprint.
Recommended
Sensor Interface and Signal Conditioning
Simple sensor interface boards for HVAC, agriculture, and building automation pair the PIC16C56AT-20/SS with analog sensors via external op-amps and ADC front-ends. The MCU's 12 GPIO pins read multiple discrete sensor contacts or drive a low-cost external ADC such as the MCP3001 over bit-banged SPI. The 20MHz PIC core executes threshold logic, hysteresis control, and alarm-flag handling in real time. The integrated watchdog timer recovers from software lock-ups caused by EMI in industrial environments. The 1.5KB OTP program memory holds sensor calibration tables and alarm thresholds. The 20-pin SSOP footprint is small enough to fit inside sensor housings. For designs that need field reprogrammability of calibration constants, the PIC16F54-I/SS flash version is the natural upgrade in the same SSOP-20 package.
Recommended
Smoke Detector and Safety Logic Boards
Low-cost residential smoke detectors, CO sensor boards, and similar safety logic circuits use the PIC16C56AT-20/SS to run the alarm-decision algorithm, periodic sensor self-test, and piezo buzzer drive. The 25-byte RAM holds a state vector and a 10-minute rolling average buffer for the photoelectric or electrochemical sensor. Twelve GPIO drive the alarm horn, status LED, low-battery indicator, and hush button. The integrated watchdog timer combined with Power-on Reset ensures the detector always comes up in a known configuration - a regulatory expectation in safety-critical consumer products. OTP memory prevents firmware tampering, which is mandatory for safety certifications. The SSOP-20 package is small enough to fit inside the detector's main chassis. The PIC16C56A-20I/SS variant is recommended for detector SKUs sold into regions with harsher temperature requirements.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C56AT-20/SS β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C56AT-04E/SS | PIC16C56A-20I/SS | PIC16C56AT-20I/SS | PIC16C56AT-04/SS | PIC16F54-I/SS |
|---|---|---|---|---|---|---|
| Package | 20-pin SSOP | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same | 20-pin SSOP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Core | PIC 8-bit RISC | PIC 8-bit RISC | PIC 8-bit RISC | PIC 8-bit RISC | PIC 8-bit RISC | PIC 8-bit RISC |
| Max Clock Speed | 20 MHz | 4 MHz | 20 MHz | 20 MHz | 4 MHz | 20 MHz |
| Program Memory | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 1.5 KB OTP | 0.75 KB Flash |
| Data RAM | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes | 25 bytes |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 12 |
| Operating Temperature | 0C to +70C (commercial) | -40C to +125C (extended) | -40C to +85C (industrial) | -40C to +85C (industrial) | 0C to +70C (commercial) | -40C to +85C (industrial) |
| Memory Type | OTP (one-time programmable) | OTP | OTP | OTP | OTP | Flash (reprogrammable) |
Key Differentiators
- One-Time-Programmable memory reduces BOM cost (vs PIC16F54-I/SS)
- 20 MHz max clock with 1.5 KB OTP fits the 8-bit baseline niche (vs PIC16C56AT-04/SS)
- Commercial temperature grade at the lowest tier price (vs PIC16C56A-20I/SS)
Design Notes
Decouple VDD (pin 14) with a 100nF X7R ceramic capacitor placed within 5mm of the package pin. For boards with long supply traces or noisy switching loads, add a bulk 10uF tantalum or aluminum-polymer capacitor at the regulator output. The PIC16C5x baseline core has a relatively high transient current during OSC2 transitions, so a low-ESR bypass capacitor directly on the SSOP-20 VDD pin is mandatory. Estimated: with VDD=5V and 20MHz clock, the MCU draws approximately 5-7mA active plus I/O drive current; total supply current for a typical application is 10-20mA.
Estimated: the PIC16C56AT-20/SS dissipates approximately 50-100mW under typical 5V/20MHz operation, well within the SSOP-20 theta_JA of approximately 100-120 C/W (per Microchip package thermal data). No heatsink is required for commercial 0C to +70C ambient. However, in sealed enclosures with high ambient temperatures or stacked PCB designs, the designer should verify junction temperature using theta_JA and the actual application power dissipation. The industrial PIC16C56A-20I/SS variant offers a wider -40C to +85C operating window for harsher environments.
The 20-pin SSOP package has a 0.65mm pin pitch. Use NSMD (non-solder-mask-defined) pads with a pad width of approximately 0.40mm and length 1.5mm for reliable paste deposition. Place the MCLR/VPP pull-up resistor (typically 10kohm) close to pin 4 to avoid noise-induced resets. Route the OSC1/OSC2 traces short and symmetric; for crystal operation, place load capacitors within 2-3mm of pins 15-16. A ground plane under the SSOP-20 package improves both thermal dissipation and EMI immunity. For production programming access, expose the MCLR/VPP and ICSCLK/ICSDAT (RB6/RB7) pins to test points or a programming header.
Three common pitfalls when designing with the PIC16C56AT-20/SS: (1) OTP memory cannot be electrically erased - the 'T' in 'AT' indicates tape-and-reel packaging only, not a debug feature; (2) configuring unused RB pins as outputs (rather than inputs) without internal pull-ups can cause floating-input current draw of up to 100uA per pin; (3) MCLR pin must never be left floating - always tie it to VDD through a 10kohm resistor or the device may intermittently reset due to capacitive coupling. Always verify the OSC configuration bits match the actual oscillator hardware (XT, HS, LP) or the device may fail to start.
Compliance Information
RoHS and lead-free status declared by Microchip on the SSOP-20 product family. AEC-Q100 not applicable - the 'A' suffix in PIC16C56AT-20 denotes automotive temperature grade and tape-and-reel, not AEC-Q100 qualification; choose PIC16C56A-20I/SS or PIC16F54-I/SS for AEC-Q100-grade applications.
