ATMEGA128L-8MNR - 8-bit AVR MCU 128KB Flash 64-QFN | Microchip
MPN: ATMEGA128L-8MNR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.84 | $5.84 |
| 10 | $5.55 | $55.50 |
| 100 | $5.2 | $520.00 |
| 500 | $4.9 | $2,450.00 |
| 1,000 | $4.55 | $4,550.00 |
ATMEGA128L-8MNR Overview
A microcontroller unit (MCU) is a single-chip computer that integrates a processor core, program memory, data memory, and peripherals such as timers, serial interfaces, and analog-to-digital converters. Within the semiconductor hierarchy, this device belongs to the AVR ATmega family of 8-bit microcontrollers under the broader power-management and embedded-processing category. Its Advanced RISC architecture provides 133 powerful instructions, most of which execute in a single clock cycle, delivering high code efficiency and MIPS-per-megahertz performance.
Key features include 64 K x 16 organization of Flash program memory supporting both ISP (In-System Programming) and IAP (In-Application Programming), 53 general-purpose I/O lines, and an 8-channel 10-bit A/D converter. The JTAG boundary-scan and on-chip debug capability simplify development, while the extended industrial temperature range of the MNR suffix (up to 105C per distributor listings) suits harsh environments.
Architecturally, the AVR core uses a Harvard structure with separate program and data buses, 32 general-purpose working registers directly connected to the ALU, allowing two independent registers to be accessed in one instruction executed in one clock cycle. The device supports boot-code sections with write-protect, an 8-bit and a 16-bit timer/counter with PWM, two USARTs, SPI, TWI (I2C-compatible), and an analog comparator.
Typical applications include industrial automation and control nodes, building and HVAC controllers, sensor data acquisition systems, battery-powered instrumentation (leveraging the 2.7 V low-voltage operation), and legacy ATmega103 board upgrades, since the ATmega128 is 100% pin compatible with ATmega103.
When designing with this part, note that the MLF/QFN exposed pad should be soldered to a grounded PCB land pattern for both thermal dissipation and mechanical reliability, and that the 8 MHz speed grade with the L suffix allows full functionality down to 2.7 V, whereas the 16 MHz ATMEGA128 variants require 4.5 V to 5.5 V.
This page synthesizes distributor pricing (as of 2026-09-16), verified drop-in alternatives within the AVR ATmega MLF-64 family, and practical design guidance not found in the manufacturer datasheet, providing procurement and engineering teams a single citable reference.
Drop-in alternatives for ATMEGA128L-8MNR — 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 ATMEGA128L-8MNR (same form factor and footprint) — differing in Package, RoHS Status, Timers/Counters, SRAM, Supply Voltage Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA128L-8MUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$11.75 / Unit
View Datasheet →ATMEGA128L-8MU
✅ Drop-In✓ In Stock
$12.39 / Unit
View Datasheet →ATMEGA128-16MUR
✅ Drop-In✓ In Stock
$8.4 / Unit
View Datasheet →ATMEGA1281V-8MUR
✅ Drop-In✓ In Stock
$4.02 / Unit
View Datasheet →ATMEGA1281-16MUR
✅ Drop-In✓ In Stock
$8.78 / Unit
View Datasheet →ATMEGA128L-8MNR Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Clock Speed | 8 MHz |
| Flash Program Memory | 128 KB (64K x 16) |
| SRAM | 4 KB |
| EEPROM | 4 KB |
| Supply Voltage | 2.7 V to 5.5 V |
| Data Bus Width | 8 bit |
| I/O Ports | 53 I/O lines |
| ADC | 8-channel, 10-bit |
| Interface Types | JTAG, SPI, TWI (I2C), USART x2 |
| Instructions | 133 instructions, most single-cycle |
| Package | 64-QFN (9x9 mm), VFQFN with exposed pad |
| Mounting Type | Surface Mount |
| Number of Terminals | 64 |
| Programming Method | ISP (In-System), IAP (In-Application), JTAG |
| On-Chip Debug | JTAG on-chip debugging |
| Lifecycle Stage | ACTIVE |
ATMEGA128L-8MNR 64-qfn (9x9 mm), vfqfn with exposed pad Pin Configuration Guide
Pin configuration for ATMEGA128L-8MNR (64-qfn (9x9 mm), vfqfn with exposed pad 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 ATMEGA128L-8MNR.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA128L-8MNR is suitable for 6 applications: Industrial Automation and Control Nodes, Sensor Data Acquisition Systems, Battery-Powered Portable Instrumentation, Legacy ATmega103 Board Upgrades, Building Automation and HVAC Controllers, Embedded Communication Gateways.
Industrial Automation and Control Nodes
The ATMEGA128L-8MNR fits industrial control nodes because its 128 KB Flash accommodates substantial state-machine and communication stacks while the 53 general-purpose I/O lines drive relays, optocouplers, and status indicators directly. The 2.7 V to 5.5 V supply range tolerates the noisy, poorly regulated rails common on factory floor 24 V-derived subsystems. In a typical node, the 8 MHz AVR core runs the Modbus RTU stack on USART0, samples analog process signals with the 8-channel 10-bit ADC, and uses the 16-bit timer/counter with PWM for actuator control. The JTAG interface allows field diagnostics during commissioning, and the industrial temperature grade supports control cabinets and motor-junction environments where consumer-grade MCUs are unsuitable.
Recommended
Sensor Data Acquisition Systems
The 8-channel 10-bit ADC, 4 KB SRAM for sample buffering, and 4 KB EEPROM for calibration constants make the ATMEGA128L-8MNR a strong fit for multi-channel data acquisition. A typical logger samples several analog channels under timer control, applies stored offset/gain correction from EEPROM, aggregates records in SRAM, and uploads them via USART or SPI to a radio or SD bridge. Running from 2.7 V allows direct connection to two-cell LiSOCl2 or a single Li-ion cell through a small LDO, and the AVR sleep modes let the MCU duty-cycle between 8 MHz bursts and microwatt idle states, extending battery life substantially. The 128 KB Flash leaves ample room for filtering libraries and communication protocol firmware.
Recommended
Battery-Powered Portable Instrumentation
Because the L speed grade runs at the full 8 MHz down to 2.7 V, the ATMEGA128L-8MNR can be powered directly from a 3 V coin cell boost stage or a two-cell alkaline stack without a regulated 5 V rail, reducing BOM cost and quiescent losses. Handheld meters, portable environmental monitors, and field-test tools benefit from the ADC's internal reference options, the TWI bus for low-power display and RTC peripherals, and the EEPROM for storing user settings through power cycles. Designers should exploit the power-down sleep mode (with watchdog wake) between measurements; the AVR's architecture resumes execution deterministically, which simplifies timing-critical sampling routines in battery budgets measured in microamp-hours.
Recommended
Legacy ATmega103 Board Upgrades
According to the Microchip ATmega128 datasheet, the ATmega128 is 100% pin compatible with the ATmega103 and can replace it on existing printed circuit boards, making the ATMEGA128L-8MNR the standard upgrade path for aging ATmega103 designs. The MLF 64-QFN footprint preserves the original land pattern while doubling usable Flash (128 KB vs 103 KB limitation on the older part), adding TWI, doubling USART count to two, and introducing the JTAG debug port. Microchip application note 'Replacing ATmega103 by ATmega128' documents fuse and MCU-control-register differences engineers must set - notably M103C fuse programming for full backward compatibility - so most legacy firmware runs unmodified on the new silicon.
Recommended
Building Automation and HVAC Controllers
HVAC and building-automation controllers need many I/O, multiple serial links, and EEPROM-backed configuration - all provided by the ATMEGA128L-8MNR. Its 53 I/O lines read thermostats and drive zone valves; USART0 handles RS-485 BACnet/Modbus field buses through an external transceiver, while TWI connects RTC and humidity sensors; the 10-bit ADC reads thermistor strings. The 4 KB EEPROM retains setpoint tables across power outages without external nonvolatile memory. Operating down to 2.7 V suits bus-powered nodes, and the 8 MHz clock keeps EMC profiles gentle compared with faster controllers, easing conducted-emissions compliance in metal control enclosures. JTAG debugging simplifies on-site firmware updates during installation.
Recommended
Embedded Communication Gateways
With two USARTs, SPI, and TWI operating concurrently, the ATMEGA128L-8MNR serves as a protocol-conversion gateway: for example, translating a Modbus RTU RS-485 network to SPI-attached Ethernet modules or TWI sensor clusters. The 128 KB Flash holds both protocol stacks plus buffering logic, and the 4 KB SRAM provides frame buffers for store-and-forward conversion. The 8 MHz RISC core with single-cycle instruction execution delivers adequate throughput for multi-slave polling at typical industrial baud rates (9600 to 115200). Designers should verify USART and SPI interrupt-latency budgets at full load, and use the boot-loader IAP capability so gateway firmware can be updated remotely over the fieldbus without physical access.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA128L-8MNR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA128L-8MUR | ATMEGA128L-8MU | ATMEGA128-16MUR | ATMEGA1281V-8MUR | ATMEGA128L-8AJ |
|---|---|---|---|---|---|---|
| Package | 64-QFN (9x9) MLF | 64-QFN (9x9) MLF - same | 64-QFN (9x9) MLF - same | 64-QFN (9x9) MLF - same | 64-QFN (9x9) MLF - same | 64-TQFP - different |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | |
| Core / Clock Speed | AVR 8-bit, 8 MHz | AVR 8-bit, 8 MHz | AVR 8-bit, 16 MHz | AVR 8-bit, 8 MHz | AVR 8-bit, 8 MHz | |
| Flash Memory | 128 KB | 128 KB | 128 KB | 128 KB | 128 KB | |
| SRAM / EEPROM | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB | 4 KB / 4 KB | |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 4.5 V to 5.5 V | 1.8 V to 5.5 V | 2.7 V to 5.5 V | |
| JTAG On-Chip Debug | Yes | Yes | Yes | Yes | Yes | |
| Same PCB Land Pattern | Reference | Yes (drop-in) | Yes (drop-in) | Yes (drop-in) | No (TQFP) |
Key Differentiators
- Full low-voltage operation at full speed (vs ATMEGA128-16MUR)
- Same silicon in reel format (vs ATMEGA128L-8MUR)
- Original ATmega128 core vs revised family (vs ATMEGA1281V-8MUR)
Design Notes
The 64-QFN (9x9) MLF package has an exposed pad on the underside that must be soldered to the PCB land pattern. Microchip's QFN/MLF application notes recommend a solder-paste stencil with approximately 50-70% coverage on the pad aperture and thermal vias (array of 0.3 mm vias) connecting to a ground plane. Skip the exposed-pad connection and you risk intermittent ground returns, degraded ADC accuracy, and mechanical failure during thermal cycling or rework.
Place 100 nF ceramic decoupling capacitors at each VCC/GND pin pair and a bulk 4.7-10 uF capacitor near the supply entry. Because the AVR clock can run from a crystal, external RC, or internal oscillator, select the CKOPT fuse and crystal load capacitors per the datasheet oscillator section - at 8 MHz a parallel crystal with 12-22 pF load caps is typical. In low-voltage (2.7 V) designs, verify brown-out reset (BOD) fuse settings so the MCU does not execute corrupted code during supply sag.
Do not overlook the M103C compatibility fuse: if set, the ATmega128 behaves as an ATmega103 and the extended features (second USART, TWI additions) are disabled. New designs should leave it unprogrammed. Also confirm JTAGEN fuse state - when JTAG is enabled, Port C pins used for JTAG cannot serve general I/O unless the JTD bit in MCUCSR is set at runtime. Finally, respect ISP connector orientation; reversed SPI programming headers are among the most common field-failure causes for this family.
Estimated: the ATmega128 at 8 MHz and 5 V typically dissipates well under 250 mW (core active current in the low-milliamp range per datasheet electrical characteristics), so a full-ground exposed pad with standard 2-layer copper is thermally adequate. Only designs driving heavy loads directly from I/O pins (up to 20 mA each, 200 mA total device limit per family specification) need to budget additional copper; sum I/O currents against the device total limit in your thermal review.
Compliance Information
Compliance data not present in the retrieved web data. Microchip standard product is generally RoHS-compliant, but confirm on the official Microchip product page environmental section before procurement decisions.
