ATMEGA165A-AUR - AVR 8-Bit MCU 16KB Flash 16MHz TQFP-64 | Microchip
MPN: ATMEGA165A-AUR β Active| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
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ATMEGA165A-AUR Overview
An 8-bit AVR microcontroller is a member of the broader microcontroller (MCU) product hierarchy: microcontroller -> embedded processor -> integrated circuit. The AVR core uses an advanced RISC architecture in which 133 powerful instructions are mostly executed in a single clock cycle, and eight general-purpose working registers are directly connected to the ALU. This Harvard-architecture design delivers throughput approaching 1 MIPS per MHz, allowing system designers to trade clock speed against power consumption.
Key differentiating features of the ATMEGA165A-AUR include fully static operation, up to 16 MIPS throughput at 16MHz, a wide 2.7V to 5.5V supply voltage range, and 53 general-purpose I/O lines across multiple GPIO ports. On-chip peripherals include SPI, UART/USART, and USI serial interfaces for connectivity, along with in-system self-programmable Flash that enables field firmware updates without removing the device from the PCB.
Technically, the ATmega165A belongs to the ATmega165A/325A/645A pin-compatible family, which shares the same 64-pin TQFP footprint and peripheral set while scaling Flash from 16KB to 64KB. This family scalability lets a single PCB layout migrate across memory tiers. The A-suffix generation is the second-generation refresh of the original ATmega165, improving analog and power characteristics while preserving code compatibility, and the -AUR ordering code denotes industrial temperature grade, tape-and-reel packing, and RoHS/green packaging.
Typical applications include industrial control panels, sensor hubs and data loggers, building automation nodes, motor control front ends, and legacy AVR designs requiring a long-lifecycle drop-in family member. The 53 I/O lines and multiple serial interfaces make it well suited to designs that must drive displays, keypads, and communication links concurrently.
A key design consideration is clock selection: the internal RC oscillator reduces BOM cost, but external crystal operation on the XTAL pins is recommended when UART communication demands precise baud-rate accuracy, particularly at 5V and elevated temperature.
This page synthesizes verified distributor data, family drop-in alternatives, and practical design notes that go beyond what a single datasheet page provides.
Drop-in alternatives for ATMEGA165A-AUR 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 ATMEGA165A-AUR (same form factor and footprint) β differing in Package, Instruction Set, Mounting Type, Core Processor, Number of I/O Lines.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA165PA-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.54 / Unit
View Datasheet βATMEGA325A-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA645A-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA165PA-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.54 / Unit
View Datasheet βATMEGA169A-AUR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA165A-AUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed (Max Clock) | 16 MHz |
| Flash Memory | 16 KB (8K x 16) |
| SRAM | 1 KB |
| EEPROM | 512 B |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Number of I/O | 53 |
| Connectivity | SPI, UART/USART, USI |
| Instruction Set | 133 powerful instructions, most single-cycle |
| Throughput | Up to 16 MIPS at 16 MHz |
| Mounting Type | Surface Mount |
| Package | 64-TQFP (14 x 14 mm) |
| Operating Temperature | Industrial grade (-40C to +85C) |
| Packaging | Tape & Reel (TR) |
| Terminal Form | Gull Wing |
| Life Cycle Stage | ACTIVE |
ATMEGA165A-AUR 64-tqfp (14 x 14 mm) Pin Configuration Guide
Pin configuration for ATMEGA165A-AUR (64-tqfp (14 x 14 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for ATMEGA165A-AUR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA165A-AUR is suitable for 6 applications: Industrial Control Panels, Sensor Hubs and Data Loggers, Building Automation Nodes, Embedded Legacy AVR Replacements, Motor Control Front Ends, Handheld and Portable Instruments.
Industrial Control Panels
The ATMEGA165A-AUR fits industrial control panels because its 53 GPIO lines can directly drive relays, indicators, and keypads without port expanders, while the industrial -40C to +85C temperature grade matches cabinet environments. The 2.7V to 5.5V supply range tolerates unregulated 5V rail sag, and the AVR single-cycle RISC core delivers 16 MIPS at 16MHz for deterministic scan loops. SPI and UART/USART links connect panel controllers to PLC backplanes; the In-System Programmable 16KB Flash allows field firmware updates via boot loader without removing the device from the PCB.
Recommended
Sensor Hubs and Data Loggers
For sensor aggregation, the ATMEGA165A-AUR combines 1KB SRAM for sample buffering, 512B EEPROM for calibration constants that survive power loss, and SPI/USI interfaces for ADCs and digital sensors. The fully static core can be clock-gated or slowed to conserve energy between samples, and the picoPower ATMEGA165PA-AUR variant drops sleep current further for the same footprint when battery life is critical. The 16MHz maximum clock provides headroom for filtering and protocol handling in real time, and 16KB Flash accommodates a full sensing plus communications firmware stack.
Recommended
Building Automation Nodes
Building automation nodes benefit from the ATMEGA165A-AUR's UART/USART for RS-485 style field buses and its abundant I/O for actuators, occupancy sensors, and damper drives. The industrial temperature rating covers mechanical rooms and rooftop enclosures, while the wide 2.7V to 5.5V input allows operation from either 3.3V or 5V logic supplies within the same PCB design. In-System Programmable Flash enables remote firmware reconfiguration of installed nodes. Because the ATmega165A/325A/645A family shares one 64-TQFP footprint, node SKUs can span memory tiers with a single PCB.
Recommended
Embedded Legacy AVR Replacements
Many mature products were designed around classic ATmega devices, and the ATMEGA165A-AUR serves as a sourcing-safe, active-lifecycle member of that same architecture. It is code compatible at the AVR instruction level and footprint-compatible with the ATmega165A/325A/645A family in 64-TQFP, allowing repairs and continuing production of legacy boards without redesign. The A-generation refresh improves on the original ATmega165 die while preserving register maps and peripherals, so existing firmware typically assembles and runs unmodified, minimizing qualification effort for service replacements.
Recommended
Motor Control Front Ends
In low-complexity motor control, the ATMEGA165A-AUR's 16 MIPS throughput, hardware SPI for digital gate drivers or smart power modules, and multiple timer-driven PWM output pins form a compact control front end. The 53 I/O lines handle rotor-position sensors, current-shunt comparators, and fault inputs in parallel. The 5.5V maximum supply matches standard 5V gate-driver logic, and the industrial temperature grade suits drive enclosures. Firmware resides in the 16KB self-programmable Flash, so commutation tables and protection routines can be tuned in the field over the UART link.
Recommended
Handheld and Portable Instruments
Portable instruments use the ATMEGA165A-AUR for its balance of processing throughput and power manageability: the fully static AVR core can run from the internal RC oscillator at low frequency for measurement standby, then accelerate to 16MHz for computation and display refresh. The 512B EEPROM stores user calibration and settings, while SPI and USI interface LCD drivers, EEPROMs, and precision ADCs. Designers targeting multi-year battery life should specify the pin-compatible ATMEGA165PA-AUR picoPower variant, whose identical 64-TQFP footprint makes the swap a simple BOM change.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA165A-AUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA165PA-AUR | ATMEGA325A-AUR | ATMEGA645A-AUR | ATMEGA169A-AUR |
|---|---|---|---|---|---|
| Package | 64-TQFP (14x14 mm) | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Flash | 16 KB | 16 KB | 32 KB | 64 KB | 16 KB |
| Core / Speed | AVR 8-bit, 16 MHz | AVR 8-bit, 16 MHz | AVR 8-bit, 16 MHz | AVR 8-bit, 16 MHz | AVR 8-bit, 16 MHz |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| SRAM | 1 KB | 1 KB | 2 KB | 4 KB | 1 KB |
| EEPROM | 512 B | 512 B | 1 KB | 2 KB | 512 B |
| Special Features | SPI, UART/USART, USI; ISP Flash | picoPower low-sleep-current | 2x Flash on same footprint | 4x Flash, largest family member | integrated segment LCD controller |
Key Differentiators
- Baseline 16KB density at family price point (vs ATMEGA325A-AUR)
- Lower power consumption option in same footprint (vs ATMEGA165PA-AUR)
- General-purpose I/O focus versus display specialization (vs ATMEGA169A-AUR)
- Active lifecycle with pin-compatible upgrade headroom (vs ATMEGA645A-AUR)
Design Notes
Decouple every VCC/GND pair of the 64-TQFP with 100 nF ceramic capacitors placed within a few millimeters of the pins, plus one bulk 4.7 uF to 10 uF capacitor near the device. The AVR core draws transient current on every clock edge; long decoupling loops cause rail bounce that appears as spurious resets or EEPROM corruption. When running from a switching supply near the 5.5V maximum, verify overshoot during load transients - exceeding the absolute maximum VCC even briefly can damage the device.
Use an external crystal on the XTAL pins when UART baud rates must be accurate, or when communicating over RS-485 or other long links. The internal RC oscillator tolerances can skew UART timing across temperature, causing framing errors at the edges of the industrial temperature range. Enable the crystal's built-in low-power or full-swing mode per the manufacturer datasheet and load it with the correct stray-capacitance-compensated capacitors for reliable startup at cold temperature.
The maximum clock frequency scales with VCC on AVR classic devices: verify the datasheet's frequency-versus-voltage curve before running 16MHz at the low end of the 2.7V range, or derate the clock accordingly. Also note the pin-compatible migration path (ATmega165A to 325A to 645A) requires updating bootloader vector addresses and linker memory maps because Flash and SRAM sizes differ, even though the footprint and register interface stay identical.
The 64-TQFP 0.5 mm lead pitch requires solder-mask-defined or NSMD pads per Microchip's recommended land pattern; keep traces short under the die area and use the center region for a local ground pour with thermal vias. Route crystal traces away from UART and switching signals, and provide test points on ISP (SPI) lines so production programming and field debugging are possible without removing the MCU from the board.
Compliance Information
Distributor listings for the ATMEGA165A-AUR describe green/industrial packaging typical of current Microchip AVR parts, but explicit RoHS/REACH compliance statements were not present in the verified web data - confirm on the official Microchip product page.