ATMEGA8535L-8AU - 8-bit AVR MCU 8KB Flash 44-TQFP | Microchip
MPN: ATMEGA8535L-8AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.75 | $4.75 |
| 10 | $4.28 | $42.80 |
| 100 | $3.82 | $382.00 |
| 500 | $3.45 | $1,725.00 |
| 1,000 | $3.12 | $3,120.00 |
ATMEGA8535L-8AU Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory, data memory, and peripherals such as timers, serial interfaces, and analog-to-digital converters. Within the semiconductor taxonomy, the ATMEGA8535L-8AU sits in the hierarchy of 8-bit MCU -> microcontroller -> embedded processor -> integrated circuit, and it belongs to the AVR ATmega family, which is known for its single-cycle RISC execution and deterministic interrupt latency.
Key features include 8 KB Flash (4K x 16), 512 B SRAM, 512 B EEPROM, 32 programmable I/O lines, two 8-bit and one 16-bit timer/counter, a 4-channel PWM unit, an 8-channel 10-bit ADC, a programmable USART, a master/slave SPI, and a byte-oriented two-wire serial interface (I2C). The device delivers up to 8 MIPS at 8 MHz and supports six sleep modes for low-power operation.
The ATmega8535L core uses the enhanced AVR RISC architecture with 130 powerful instructions, most executing in a single clock cycle. The 'L' suffix denotes the low-voltage version, which operates from 2.7 V to 5.5 V and is speed-graded to 8 MHz, while the standard ATmega8535 runs at 4.5-5.5 V and up to 16 MHz. This makes the L-grade part attractive for battery-powered and 3.3 V mixed-supply designs.
Typical applications include industrial control panels, battery chargers, motor control, home appliances, sensor interfaces, and legacy 8-bit embedded designs that require a proven, well-documented AVR core with generous I/O count. The 44-TQFP package offers a compact 10x10 mm footprint suitable for space-constrained boards.
When designing with this device, ensure the supply is decoupled with a 100 nF ceramic capacitor close to each VCC pin, and note that the internal RC oscillator is factory-calibrated to +/-3% at 8 MHz, which may be adequate for many applications without an external crystal. The ATmega8535L is a mature, active-lifecycle part with extensive third-party toolchain support.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a single reference for selection, replacement, and layout decisions.
Drop-in alternatives for ATMEGA8535L-8AU 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 ATMEGA8535L-8AU (same form factor and footprint) β differing in ADC, Instruction Set, Maximum Clock Frequency, Operating Temperature, Package.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA8535L-8AUR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA8535-16AU
β Drop-Inβ In Stock
$3.48 / Unit
View Datasheet βATMEGA8535L-8MU
β Drop-Inβ In Stock
$3.95 / Unit
View Datasheet βATMEGA8535L-8AUR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA8535-16AUR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA8535L-8AU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Program Memory Size | 8 KB Flash (4K x 16) |
| SRAM | 512 B |
| EEPROM | 512 B |
| Maximum Clock Frequency | 8 MHz (L version) |
| Throughput | 8 MIPS at 8 MHz |
| Operating Voltage Range | 2.7 V to 5.5 V |
| Programmable I/O Lines | 32 |
| ADC | 8-channel, 10-bit |
| Timers | Two 8-bit, one 16-bit |
| PWM Channels | 4 |
| Serial Interfaces | USART, SPI, TWI (I2C) |
| Package | 44-lead TQFP (10x10 mm) |
| Operating Temperature | -40C to +85C |
| Instruction Set | 130 instructions, most single-clock |
| Sleep Modes | 6 (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, Extended Standby) |
| Internal RC Oscillator | 8 MHz calibrated, +/-3% |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| REACH Status | Compliant |
ATMEGA8535L-8AU Pin Configuration
| Pin 1 | PB0 β Port B, bit 0 (T0/XCK) |
| Pin 2 | PB1 β Port B, bit 1 (T1) |
| Pin 3 | PB2 β Port B, bit 2 (INT2/AIN0) |
| Pin 4 | PB3 β Port B, bit 3 (OC0/AIN1) |
| Pin 5 | PB4 β Port B, bit 4 (SS) |
| Pin 6 | PB5 β Port B, bit 5 (MOSI) |
| Pin 7 | PB6 β Port B, bit 6 (MISO) |
| Pin 8 | PB7 β Port B, bit 7 (SCK) |
| Pin 9 | RESET β Reset input (active low) |
| Pin 10 | VCC β Digital supply voltage |
| Pin 11 | GND β Ground |
| Pin 12 | XTAL2 β Crystal oscillator output |
| Pin 13 | XTAL1 β Crystal oscillator input |
| Pin 14 | PD0 β Port D, bit 0 (RXD) |
| Pin 15 | PD1 β Port D, bit 1 (TXD) |
| Pin 16 | PD2 β Port D, bit 2 (INT0) |
| Pin 17 | PD3 β Port D, bit 3 (INT1) |
| Pin 18 | PD4 β Port D, bit 4 (OC1B) |
| Pin 19 | PD5 β Port D, bit 5 (OC1A) |
| Pin 20 | PD6 β Port D, bit 6 (ICP1) |
| Pin 21 | PD7 β Port D, bit 7 (OC2) |
| Pin 22 | PC0 β Port C, bit 0 (SCL) |
| Pin 23 | PC1 β Port C, bit 1 (SDA) |
| Pin 24 | PC2 β Port C, bit 2 (TCK) |
| Pin 25 | PC3 β Port C, bit 3 (TMS) |
| Pin 26 | PC4 β Port C, bit 4 (TDO) |
| Pin 27 | PC5 β Port C, bit 5 (TDI) |
| Pin 28 | PC6 β Port C, bit 6 (TOSC1) |
| Pin 29 | PC7 β Port C, bit 7 (TOSC2) |
| Pin 30 | AVCC β Analog supply voltage |
| Pin 31 | GND β Ground |
| Pin 32 | AREF β Analog reference voltage |
| Pin 33 | PA7 β Port A, bit 7 (ADC7) |
| Pin 34 | PA6 β Port A, bit 6 (ADC6) |
| Pin 35 | PA5 β Port A, bit 5 (ADC5) |
| Pin 36 | PA4 β Port A, bit 4 (ADC4) |
| Pin 37 | PA3 β Port A, bit 3 (ADC3) |
| Pin 38 | PA2 β Port A, bit 2 (ADC2) |
| Pin 39 | PA1 β Port A, bit 1 (ADC1) |
| Pin 40 | PA0 β Port A, bit 0 (ADC0) |
| Pin 41 | VCC β Digital supply voltage |
| Pin 42 | GND β Ground |
| Pin 43 | NC β Not connected (per datasheet) |
| Pin 44 | NC β Not connected (per datasheet) |
Typical Applications
ATMEGA8535L-8AU is suitable for 6 applications: Industrial Control Panels, Battery-Powered Sensor Nodes, Home Appliances and White Goods, Motor Control and Drives, Legacy 8-bit Embedded Redesigns, Data Logging and Instrumentation.
Industrial Control Panels
The ATMEGA8535L-8AU fits industrial control panels because its 32 programmable I/O lines and 8-channel 10-bit ADC can directly interface with pushbuttons, relays, and analog sensors without external multiplexing. Operating from 2.7-5.5 V, it tolerates the noisy 5 V rails common in factory equipment, and the 44-lead TQFP's 10x10 mm footprint saves board space in DIN-rail modules. The device's 8 KB Flash holds control logic and lookup tables, while the 512 B EEPROM stores calibration constants across power cycles. A typical implementation uses the USART for an RS-485 or Modbus interface and the 16-bit timer for precise pulse generation. Unlike a 32-bit MCU, the AVR core's deterministic single-cycle execution simplifies worst-case timing analysis, but designers must add external TVS protection on field-facing I/O to survive industrial transients.
Recommended
Battery-Powered Sensor Nodes
The ATMEGA8535L-8AU is well suited to battery-powered sensor nodes because its 2.7-5.5 V supply range allows direct operation from a single Li-ion cell or two AA cells without a boost converter, and its six sleep modes reduce current to the microamp range between measurements. The 8-channel 10-bit ADC samples thermistors, strain gauges, or photodiodes directly, while the TWI (I2C) interface connects to low-power EEPROM or sensor ICs. In a typical duty-cycled design, the MCU wakes on a timer interrupt, converts a few channels, transmits via USART or SPI, and returns to Power-down mode. The trade-off is that the 8 MHz L-grade core limits throughput, so designers should keep wake-time processing short. Adding a 32.768 kHz watch crystal enables accurate long-interval timing at minimal current.
Recommended
Home Appliances and White Goods
The ATMEGA8535L-8AU is widely used in home appliances such as washing machines, dishwashers, and microwave ovens because it combines 32 I/O lines, a 10-bit ADC, and hardware PWM in a single 44-lead TQFP, reducing component count on cost-sensitive control boards. The 4-channel PWM unit drives triacs and relays for motor and heater control, while the ADC reads temperature and level sensors. Its 2.7-5.5 V range accommodates the 5 V regulated rail typical of appliance electronics, and the -40C to +85C rating covers the internal temperatures of most white goods. The 8 KB Flash is sufficient for state-machine control logic and safety interlocks. Designers should note that the internal 8 MHz RC oscillator's +/-3% tolerance is adequate for appliance timing but an external crystal is recommended if precise timekeeping is required.
Recommended
Motor Control and Drives
The ATMEGA8535L-8AU supports motor control applications through its 16-bit timer with input capture, 4-channel PWM, and 8-channel 10-bit ADC, which together enable closed-loop speed and current control of brushed DC and stepper motors. The 8 MIPS throughput at 8 MHz is sufficient for PID loops running at a few kilohertz, and the 32 I/O lines can drive gate drivers, direction pins, and limit switches simultaneously. In a typical design, the ADC samples a shunt resistor for current feedback while the PWM modulates the H-bridge. The main limitation is that the L-grade part's 8 MHz ceiling constrains control-loop bandwidth compared with the 16 MHz ATmega8535-16AU, so high-speed field-oriented control is better served by a dedicated motor-control MCU. Adequate gate-drive isolation and dead-time insertion remain essential.
Recommended
Legacy 8-bit Embedded Redesigns
The ATMEGA8535L-8AU is a common choice for maintaining and redesigning legacy 8-bit embedded systems because it is an active-lifecycle part with a stable, well-documented AVR core and extensive toolchain support. Engineers migrating from older AT90S8535 or ATmega8535 designs can reuse existing firmware with minimal changes, since the instruction set and peripheral register map are compatible. The 44-lead TQFP footprint matches the original ATmega8535 layout, allowing direct board respins without re-routing. The 2.7-5.5 V range also permits modernization to 3.3 V logic while preserving the same code base. The main consideration is that the L-grade 8 MHz limit may require re-tuning timing loops originally written for 16 MHz operation, and any external crystal must be re-specified accordingly.
Recommended
Data Logging and Instrumentation
The ATMEGA8535L-8AU is effective in data logging and instrumentation because its 512 B EEPROM stores calibration data and configuration without external memory, while the 8-channel 10-bit ADC digitizes sensor signals and the USART streams results to a host PC or wireless module. The 8 KB Flash accommodates sampling routines, linearization tables, and communication stacks. In a typical logger, the MCU samples at fixed intervals using the 16-bit timer, averages readings to reduce noise, and writes to EEPROM or an external SPI flash. The 2.7-5.5 V supply allows operation from a 3.3 V rail, simplifying interfacing with modern sensors. Designers should account for the 10,000-cycle Flash and 100,000-cycle EEPROM endurance limits when planning write frequency, and use wear-leveling for high-rate logging.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA8535L-8AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8535L-8AUR | ATMEGA8535-16AU | ATMEGA8535L-8MU |
|---|---|---|---|---|
| Package | 44-lead TQFP (10x10 mm) | 44-lead TQFP - same | 44-lead TQFP - same | 44-pad QFN/MLF - different |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Maximum Clock Frequency | 8 MHz | 8 MHz | 16 MHz | 8 MHz |
| Operating Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 4.5 V to 5.5 V | 2.7 V to 5.5 V |
| Flash Memory | 8 KB | 8 KB | 8 KB | 8 KB |
| SRAM | 512 B | 512 B | 512 B | 512 B |
| Programmable I/O Lines | 32 | 32 | 32 | 32 |
| ADC | 8-channel, 10-bit | 8-channel, 10-bit | 8-channel, 10-bit | 8-channel, 10-bit |
| Packaging | Tray | Tape & Reel | Tray | Tray |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- Low-voltage operation down to 2.7 V (vs ATMEGA8535-16AU)
- Tape-and-reel availability for automated assembly (vs ATMEGA8535L-8AU)
- Compact QFN option with exposed pad (vs ATMEGA8535L-8MU)
- Higher speed for 5 V systems (vs ATMEGA8535-16AU)
Design Notes
Decouple every VCC and AVCC pin with a 100 nF ceramic capacitor placed as close to the pin as possible, and add a 10 uF bulk capacitor near the regulator output. The ATmega8535 datasheet recommends a separate low-pass filter (10 uH inductor plus 100 nF) on AVCC when the ADC is used, to isolate digital switching noise from the analog reference. Keep AREF decoupled with 100 nF to GND. Estimated: at 8 MHz and 5 V, core current is roughly 5-8 mA, so a 100 mA LDO is more than adequate.
Route the crystal and its two load capacitors as close to XTAL1/XTAL2 as possible, keeping the loop area small and away from switching signals. Use a ground guard ring around the crystal. For the 44-lead TQFP, connect the exposed thermal/ground pad (if present) to a solid ground plane with multiple vias. Keep the ISP header traces short and avoid routing them under the crystal or analog pins to prevent programming failures and ADC noise.
Do not exceed the 8 MHz speed grade of the L version; running the ATMEGA8535L-8AU above 8 MHz at 2.7-5.5 V violates the datasheet and causes unreliable Flash access. If migrating firmware from a 16 MHz ATmega8535, re-check all timer prescalers, UART baud rates, and software delay loops. Also verify that the reset pin is pulled high through a 10 kOhm resistor and that the ISP programmer does not hold it low during normal operation.
When using the 10-bit ADC, drive AREF from a clean, low-impedance source (for example a 2.56 V reference or a filtered AVCC) rather than the noisy digital rail. Keep analog input traces short and shielded from digital lines, and place a 100 nF capacitor from each ADC input to GND if the source impedance exceeds 10 kOhm. The datasheet specifies a maximum ADC clock of 200 kHz for full 10-bit accuracy, so set the prescaler accordingly at 8 MHz.
Compliance Information
Distributor compliance data lists the ATMEGA8535L-8AU as EU RoHS compliant, REACH compliant, and DRC conflict-free. Not AEC-Q100 qualified; automotive designs require a separately qualified part.
