ATTINY44A-SSU - 4KB Flash 20MHz 8-bit AVR MCU | Microchip
MPN: ATTINY44A-SSU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.95 | $1.95 |
| 10 | $1.72 | $17.20 |
| 100 | $1.46 | $146.00 |
| 500 | $1.28 | $640.00 |
| 1,000 | $1.12 | $1,120.00 |
ATTINY44A-SSU Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (Flash), working RAM, and programmable peripherals into one package. The 8-bit AVR RISC architecture is Harvard-based with separate program and data buses, executing most instructions in a single clock cycle. This places the ATTINY44A in the broader hierarchy: microcontroller -> embedded MCU -> semiconductor -> integrated circuit. It belongs to the tinyAVR subfamily, optimized for low pin-count, low-power applications.
Key features include a 10-bit ADC with up to 8 channels, two 8-bit timer/counters with PWM, one 16-bit timer/counter with two PWM channels, an internal calibrated 8 MHz oscillator, internal voltage reference, programmable watchdog timer with separate on-chip oscillator, and four software-selectable power-saving modes. The chip operates from 1.8 V to 5.5 V, drawing as little as sub-microamp current in power-down.
The AVR core uses single-cycle pipelined execution with a rich instruction set, simplifying C compiler code generation. ISP (In-System Programming) via SPI and debugWIRE on-chip debug eliminate the need for an external programmer port, while the peripheral touch controller supports capacitive sensing buttons for HMI.
Typical applications include battery-powered sensor nodes, LED light controllers, remote controls, low-cost motor control, consumer appliances, and IoT edge devices. The wide voltage range and deep sleep modes make it suitable for energy-harvesting designs.
Designers should configure unused pins as inputs with internal pull-ups enabled to minimize sleep current and prevent floating-node noise coupling into the analog ADC inputs.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that are not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATTINY44A-SSU — 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 ATTINY44A-SSU (same form factor and footprint) — differing in Package, ADC, Operating Temperature, EEPROM, Maximum Clock Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATTINY44A-SSUR
✅ Drop-In📋 Reference alternative (not in catalog)
ATTINY44-20SSU
✅ Drop-In📋 Reference alternative (not in catalog)
ATTINY441-SSUR
✅ Drop-In📋 Reference alternative (not in catalog)
ATTINY24A-SSU
✅ Drop-In📋 Reference alternative (not in catalog)
ATTINY412-SSF
✅ Drop-In✓ In Stock
$0.36 / Unit
View Datasheet →ATTINY412-SSNR
✅ Drop-In✓ In Stock
$0.42 / Unit
View Datasheet →ATTINY44A-SSU Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Program Memory (Flash) | 4 KB (2K x 16) |
| EEPROM | 256 bytes |
| SRAM | 256 bytes |
| Maximum Clock Frequency | 20 MHz |
| Operating Voltage (VCC) | 1.8 V to 5.5 V |
| I/O Pins | 12 |
| ADC | 10-bit, 8 channels |
| Timers/Counters | 1 x 8-bit + 1 x 16-bit (PWM) |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 14-pin SOIC (150-mil) |
| Mounting Type | Surface Mount |
| Programming Interface | ISP (SPI) + debugWIRE |
| MSL Level | 1 (Unlimited) |
| RoHS Status | Compliant |
ATTINY44A-SSU Pin Configuration
| Pin 1 | VCC — Power supply input (1.8 V to 5.5 V) |
| Pin 2 | PB0 (MOSI/DI/SDA/AIN0/OC0A/AREF/PCINT8) — Port B bit 0 / SPI MOSI / I2C SDA / ADC ch0 / Analog comparator input |
| Pin 3 | PB1 (MISO/DO/AIN1/OC0B/PCINT9) — Port B bit 1 / SPI MISO / ADC ch1 / Analog comparator input |
| Pin 4 | PB3 (PCINT11/RESET) — Reset input (active low) or Port B bit 3; weak drive strength when used as RESET per datasheet |
| Pin 5 | PB2 (SCK/USCK/SCL/ADC7/PCINT10) — Port B bit 2 / SPI SCK / I2C SCL / ADC ch7 |
| Pin 6 | PA7 (ADC6/OC1B/PCINT7) — Port A bit 7 / ADC ch6 / Timer1 channel B PWM output |
| Pin 7 | PA6 (ADC5/OC1A/PCINT6) — Port A bit 6 / ADC ch5 / Timer1 channel A PWM output |
| Pin 8 | PA5 (ADC4/OC0B/PCINT5) — Port A bit 5 / ADC ch4 / Timer0 channel B PWM output |
| Pin 9 | PA4 (ADC3/OC0A/PCINT4) — Port A bit 4 / ADC ch3 / Timer0 channel A PWM output |
| Pin 10 | PA3 (ADC2/PCINT3) — Port A bit 3 / ADC ch2 |
| Pin 11 | PA2 (ADC1/AIN0/PCINT2) — Port A bit 2 / ADC ch1 / Analog comparator positive input |
| Pin 12 | PA1 (ADC0/AIN1/PCINT1) — Port A bit 1 / ADC ch0 / Analog comparator negative input |
| Pin 13 | PA0 (PCINT0/OC0A/AREF) — Port A bit 0 / Analog reference voltage input |
| Pin 14 | GND — Ground reference |
Typical Applications
ATTINY44A-SSU is suitable for 6 applications: Battery-Powered IoT Sensor Node, LED Light Controller, Remote Control Transmitter, Low-Cost BLDC / Fan Motor Control, Consumer Appliance Interface Board, Capacitive Touch Button Controller.
Battery-Powered IoT Sensor Node
The ATTINY44A-SSU's 1.8 V to 5.5 V VCC range and picoPower sleep modes below 1 uA make it ideal for battery-powered IoT sensor nodes that wake periodically to read sensors and transmit. The 10-bit ADC with 8 channels supports temperature, light, and battery voltage measurements without an external analog frontend. Its 4 KB Flash is sufficient for a sensor reading loop, threshold detection, and a simple RF protocol stack. The 14-pin SOIC footprint fits on a coin-cell sensor module.
Recommended
LED Light Controller
The ATTINY44A-SSU's 16-bit timer with two PWM channels drives high-brightness LEDs with smooth dimming and color mixing. Its 20 MHz clock provides enough resolution for flicker-free PWM at frequencies above 1 kHz, avoiding audible noise and visible flicker. The 12 GPIO pins handle multiple LED strings, push-button inputs, and a UART link for control signals. picoPower sleep modes enable standby currents below 10 uA for mains-powered but idle luminaires.
Recommended
Remote Control Transmitter
The ATTINY44A-SSU's small 14-pin SOIC footprint and low active current around 1 mA at 1 MHz suit handheld remote controls. Its 12 GPIO lines connect to a 4x4 matrix keypad or capacitive touch buttons, while an internal timer drives the 38 kHz carrier for IR transmission. The 4 KB Flash fits button mapping, IR protocol encoding, and low-battery detection firmware. Internal 8 MHz oscillator eliminates the need for an external crystal.
Recommended
Low-Cost BLDC / Fan Motor Control
The ATTINY44A-SSU drives small brushless DC motors and fans using its 16-bit timer PWM outputs and ADC for back-EMF sensing. The wide 1.8-5.5 V VCC range supports 3.3 V and 5 V motor rails directly. With 12 GPIO, the MCU handles three half-bridge enable signals, a tachometer input, and a UART debug port. Its 20 MHz clock enables 16-bit PWM at 10 kHz with sufficient resolution for smooth torque control of small fans.
Recommended
Consumer Appliance Interface Board
The ATTINY44A-SSU operates reliably in appliance environments from -40C to +85C industrial grade, handling button inputs, LED indicators, and buzzer control for white goods interfaces. Its 256 B EEPROM stores user preferences such as last mode and calibration constants without external storage. ISP via SPI supports factory firmware updates and field service programming through a 6-pin header. The 14-pin SOIC package is well-suited to hand-rework on appliance service boards.
Recommended
Capacitive Touch Button Controller
The ATTINY44A-SSU supports up to 12 capacitive touch sensing buttons via its QTouch library and internal ADC, removing the need for a dedicated touch controller IC. Each GPIO can be configured with a sense capacitor and an internal pull-up for charge-transfer touch measurement. The 4 KB Flash accommodates QTouch libraries, debounce logic, and I2C/SPI host interface for system integration. picoPower modes keep standby touch-scan current below 5 uA.
Recommended
Recommended Products Summary
Engineering reference data for ATTINY44A-SSU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATTINY44A-SSUR | ATTINY44-20SSU | ATTINY441-SSUR | ATTINY24A-SSU | ATTINY412-SSF |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | SOIC-14 (150-mil) | SOIC-14 (150-mil) - same | SOIC-14 (150-mil) - same | SOIC-14 (150-mil) - same | SOIC-14 (150-mil) - same | SOIC-8 - not same |
| Flash Memory | 4 KB | 4 KB | 4 KB | 4 KB | 2 KB | 4 KB |
| SRAM | 256 B | 256 B | 256 B | 512 B | 128 B | 256 B |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 2.7 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| I/O Pins | 12 | 12 | 12 | 12 | 12 | 6 |
| ADC | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels | 10/12-bit, 12 channels | 10-bit, 8 channels | 10/12-bit, 6 channels |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +125C |
| Core Architecture | AVR 8-bit | AVR 8-bit | AVR 8-bit | AVR 8-bit | AVR 8-bit | AVR 8-bit (tinyAVR-2) |
Key Differentiators
- Wider voltage range with same Flash and pinout (vs ATTINY44-20SSU)
- More memory than its predecessor, same package (vs ATTINY24A-SSU)
- Upgrade path with double SRAM and 12-bit ADC option (vs ATTINY441-SSUR)
- Lower power consumption than modern tinyAVR-2 (vs ATTINY412-SSF)
Design Notes
Estimated: Sleep current at 3.3 V with WDT disabled is approximately 0.1 uA per the picoPower specification. To achieve lowest sleep current, disable the analog comparator, ADC, and Brown-out Detector (BOD) before entering Power-Down mode. Configure unused pins as inputs with internal pull-ups enabled (PUE bit set) to prevent floating nodes that leak through ESD clamps.
Place a 100 nF decoupling capacitor as close as possible to the VCC pin (pin 1) and a 10 uF bulk capacitor near the device for high-current digital transients during ADC conversion. Keep the RESET pin trace short; add a 10 kohm pull-up to VCC and a 100 nF capacitor to ground if the pin is also used as a GPIO (PB3) to avoid false reset triggers. Route the ADC analog traces away from switching digital lines to preserve ADC SNR.
Do not exceed 5.5 V on any pin including RESET; the ATTINY44A-SSU has no internal clamping above VCC. When using debugWIRE, the RESET pin must be configured as reset and not as a regular GPIO. ISP via SPI requires MOSI/MISO/SCK plus RESET to be accessible; ensure your PCB exposes these for field programming. The internal 8 MHz oscillator is factory-calibrated but may drift over temperature - use the internal PLL or external crystal for time-critical UART or PWM applications.
For ADC accuracy above 8 bits, use the internal 1.1 V bandgap reference rather than VCC, and average 4 or more ADC samples to reduce noise. Switch the ADC off between conversions (ADCSRA bit ADEN) to save current; this also prevents ADC input leakage during sleep. Route sensitive analog inputs (PB0, PB1) away from the oscillator pins and clock traces.
Compliance Information
RoHS compliant per Microchip product page. Industrial temperature grade -40C to +85C. Not AEC-Q100 qualified - choose automotive-grade variants if required. Halogen-free status not explicitly stated in provided data.
