ATMEGA329P-20MN - 20MHz 32KB Flash AVR MCU 64-QFN | Microchip
MPN: ATMEGA329P-20MN β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.41 | $2.41 |
| 10 | $2.2 | $22.00 |
| 100 | $1.98 | $198.00 |
| 500 | $1.78 | $890.00 |
| 1,000 | $1.61 | $1,610.00 |
ATMEGA329P-20MN Overview
What is an 8-bit AVR microcontroller? It is a RISC (Reduced Instruction Set Computer) microcontroller based on the Harvard architecture developed by Atmel (now Microchip). The AVR family occupies the '8-bit MCU' tier of the broader microcontroller hierarchy: microcontroller -> embedded MCU -> 8-bit MCU -> AVR RISC MCU -> picoPower family. ATmega devices are positioned at the upper end of the 8-bit AVR range, distinguished by large integrated Flash, SRAM, EEPROM, and rich peripheral sets.
Key features include 54 general-purpose I/O lines, a JTAG interface for on-chip debug, four flexible timer/counters with compare and PWM modes, a 10-bit ADC with up to 8 channels, an LCD controller supporting up to 4x25 segments, and two USART plus one TWI (I2C) and one SPI serial interface. The device operates from 2.7V to 5.5V and supports industrial temperature grades to 105 C.
The ATMEGA329P-20MN leverages the picoPower technology for ultra-low power consumption, with multiple sleep modes (idle, power-down, power-save, standby, extended standby) drawing microampere-level currents. This makes it suitable for battery-powered applications where runtime directly depends on MCU efficiency. The 64-QFN (9x9 mm) package provides good thermal performance and a compact footprint for space-constrained designs.
Typical applications include industrial control panels with integrated LCDs, consumer appliances with graphical displays, sensor hubs with LCD readouts, low-power handheld instrumentation, and embedded human-machine interface (HMI) modules. The combination of an LCD controller and large Flash/SRAM makes it a single-chip solution for graphical HMI nodes.
When designing with this device, ensure decoupling capacitors are placed as close as possible to VCC pins and that the JTAG pins are reserved for debugging access. The LCD voltage generation and segment allocation require careful board layout to avoid ghosting. Always validate low-power claims with a current profile measurement, not just datasheet typ numbers.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and practical engineering design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for ATMEGA329P-20MN 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 ATMEGA329P-20MN (same form factor and footprint) β differing in LCD Controller, Operating Temperature, Package, Program Memory (Flash), RoHS Status.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA329P-20MNR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA329P-20AN
β Drop-Inβ In Stock
$2.95 / Unit
View Datasheet βATMEGA329P-20ANR
β Drop-Inβ In Stock
$4.3 / Unit
View Datasheet βATMEGA649P-20MN
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA169P-20MN
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA329P-20MN Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Core Size | 8-bit |
| Maximum Clock Frequency | 20 MHz |
| Program Memory (Flash) | 32 KB (16K x 16) |
| SRAM | 2 KB |
| EEPROM | 1 KB |
| General Purpose I/O | 54 |
| Working Registers | 32 |
| Supply Voltage (Vcc) | 2.7 V to 5.5 V |
| ADC | 10-bit, up to 8 channels |
| Operating Temperature | -40 C to +105 C (Industrial) |
| Package | 64-QFN (9x9 mm) |
| Mounting Type | Surface Mount |
| Timers/Counters | 4 (with PWM) |
| Serial Interfaces | 2x USART, 1x TWI (I2C), 1x SPI |
| LCD Controller | Yes, up to 4x25 segments |
| JTAG Debug | Yes |
| Throughput | Up to 16 MIPS at 20 MHz |
| RoHS Status | Compliant |
ATMEGA329P-20MN Pin Configuration
| Pin 1 | SEG1 β LCD segment output 1 |
| Pin 2 | SEG2 β LCD segment output 2 |
| Pin 3 | SEG3 β LCD segment output 3 |
| Pin 4 | SEG4 β LCD segment output 4 |
| Pin 5 | SEG5 β LCD segment output 5 |
| Pin 6 | SEG6 β LCD segment output 6 |
| Pin 7 | SEG7 β LCD segment output 7 |
| Pin 8 | SEG8 β LCD segment output 8 |
| Pin 9 | SEG9 β LCD segment output 9 |
| Pin 10 | SEG10 β LCD segment output 10 |
| Pin 11 | SEG11 β LCD segment output 11 |
| Pin 12 | SEG12 β LCD segment output 12 |
| Pin 13 | SEG13 β LCD segment output 13 |
| Pin 14 | SEG14 β LCD segment output 14 |
| Pin 15 | SEG15 β LCD segment output 15 |
| Pin 16 | SEG16 β LCD segment output 16 |
| Pin 17 | SEG17 β LCD segment output 17 |
| Pin 18 | SEG18 β LCD segment output 18 |
| Pin 19 | SEG19 β LCD segment output 19 |
| Pin 20 | SEG20 β LCD segment output 20 |
| Pin 21 | SEG21 β LCD segment output 21 |
| Pin 22 | SEG22 β LCD segment output 22 |
| Pin 23 | SEG23 β LCD segment output 23 |
| Pin 24 | SEG24 β LCD segment output 24 |
| Pin 25 | COM0 β LCD common output 0 |
| Pin 26 | COM1 β LCD common output 1 |
| Pin 27 | COM2 β LCD common output 2 |
| Pin 28 | COM3 β LCD common output 3 |
| Pin 29 | PA0 β Port A bit 0 / ADC0 |
| Pin 30 | PA1 β Port A bit 1 / ADC1 |
| Pin 31 | PA2 β Port A bit 2 / ADC2 |
| Pin 32 | PA3 β Port A bit 3 / ADC3 |
| Pin 33 | PA4 β Port A bit 4 / ADC4 |
| Pin 34 | PA5 β Port A bit 5 / ADC5 |
| Pin 35 | PA6 β Port A bit 6 / ADC6 |
| Pin 36 | PA7 β Port A bit 7 / ADC7 |
| Pin 37 | VCC β Supply voltage |
| Pin 38 | GND β Ground |
| Pin 39 | AVCC β Analog supply voltage |
| Pin 40 | AREF β ADC reference voltage |
| Pin 41 | PB0 β Port B bit 0 |
| Pin 42 | PB1 β Port B bit 1 |
| Pin 43 | PB2 β Port B bit 2 / SS |
| Pin 44 | PB3 β Port B bit 3 / MOSI |
| Pin 45 | PB4 β Port B bit 4 / MISO |
| Pin 46 | PB5 β Port B bit 5 / SCK |
| Pin 47 | PB6 β Port B bit 6 / XTAL1 |
| Pin 48 | PB7 β Port B bit 7 / XTAL2 |
| Pin 49 | PC0 β Port C bit 0 / JTAG TDI |
| Pin 50 | PC1 β Port C bit 1 / JTAG TMS |
| Pin 51 | PC2 β Port C bit 2 / JTAG TCK |
| Pin 52 | PC3 β Port C bit 3 / JTAG TDO |
| Pin 53 | PC4 β Port C bit 4 |
| Pin 54 | PC5 β Port C bit 5 |
| Pin 55 | PC6 β Port C bit 6 |
| Pin 56 | PC7 β Port C bit 7 |
| Pin 57 | PD0 β Port D bit 0 / RXD0 |
| Pin 58 | PD1 β Port D bit 1 / TXD0 |
| Pin 59 | PD2 β Port D bit 2 / RXD1 |
| Pin 60 | PD3 β Port D bit 3 / TXD1 |
| Pin 61 | PD4 β Port D bit 4 |
| Pin 62 | PD5 β Port D bit 5 |
| Pin 63 | PD6 β Port D bit 6 |
| Pin 64 | PD7 β Port D bit 7 |
Typical Applications
ATMEGA329P-20MN is suitable for 7 applications: Industrial Control Panels with LCD, Consumer Appliance HMI Module, Portable Handheld Instrumentation, Automotive Dashboard Clusters, Sensor Hub with LCD Readout, IoT Edge Node with Display, Educational Development Platforms.
Industrial Control Panels with LCD
The ATMEGA329P-20MN's integrated LCD controller (up to 4x25 segments) eliminates the need for an external LCD driver IC, reducing BOM cost and PCB area in industrial control panels. Its 32 KB Flash holds typical menu/UI firmware, while 2 KB SRAM supports stack and modest variable storage. The 54 GPIO lines easily drive keypads, indicator LEDs, and relay outputs alongside the LCD. Operating voltage 2.7V-5.5V and industrial -40 C to +105 C range suit factory-floor environments.
Recommended
Consumer Appliance HMI Module
Washing machines, microwave ovens, and coffee machines need a single MCU driving a segment LCD plus keypad, buzzer, and appliance control outputs. The ATMEGA329P-20MN combines all peripherals in one 64-QFN chip, simplifying layout. Its picoPower sleep modes extend battery life in cordless appliances, and the 20 MHz clock ensures snappy menu response. The 1 KB EEPROM stores user preferences (cycle settings, language) without external memory.
Recommended
Portable Handheld Instrumentation
Handheld multimeters, environmental meters, and medical diagnostic tools benefit from the ATMEGA329P-20MN's low-power operation (microampere sleep currents), integrated 10-bit ADC for sensor readout, and LCD controller for numeric/graphical displays. The 20 MHz bus speed handles signal processing fast enough to extend active-mode duty cycle and save battery. The 64-QFN package fits slim enclosures where space is constrained.
Recommended
Automotive Dashboard Clusters
The ATMEGA329P-20MN's wide operating temperature range, integrated LCD controller for odometer/gear display, and 54 GPIO for sensor inputs suit auxiliary dashboard modules. Its 2.7V-5.5V supply range handles 12V automotive rails after regulation. Note: the -20MN variant is NOT AEC-Q100 qualified - use ATMEGA329P-20MNVAO or ATmega3290P-20AUR for production automotive. This part is suitable for aftermarket non-safety automotive electronics.
Recommended
Sensor Hub with LCD Readout
Industrial sensor hubs aggregating temperature, pressure, humidity, or flow data benefit from the ATMEGA329P-20MN's 10-bit ADC (up to 8 channels), TWI/SPI for digital sensors, and LCD controller for on-device display. The 32 KB Flash accommodates modbus stack or proprietary protocol libraries. The 1 KB EEPROM retains calibration data after power cycles, and the 2 KB SRAM buffers measurement logs.
Recommended
IoT Edge Node with Display
Edge IoT nodes displaying sensor readings locally (smart thermostats, building automation keypads) benefit from the ATMEGA329P-20MN's integrated LCD, GPIO for buttons/LEDs, and TWI/SPI/UART for connectivity modules. The picoPower architecture minimizes idle-mode consumption when the display is off. The 20 MHz clock handles local sensor fusion before forwarding aggregated data over UART/SPI to a Wi-Fi/BLE module.
Recommended
Educational Development Platforms
Universities and training programs use the ATMEGA329P-20MN as a teaching platform for embedded systems courses covering AVR assembly, C programming, ADC, timers, and LCD interfacing. The 64-QFN package is industrial-grade; for breadboard-friendly training, the TQFP-64 ATMEGA329P-20AU is preferred. The Atmel/Microchip Studio IDE supports this device with full debug and simulator, making it a strong pedagogical choice.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA329P-20MN β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA329P-20MNR | ATMEGA329P-20AN | ATMEGA649P-20MN | ATMEGA169P-20MN |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-QFN (9x9 mm) | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same | 64-QFN (9x9 mm) - same |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Flash Memory | 32 KB | 32 KB | 32 KB | 64 KB (+100%) | 16 KB (-50%) |
| SRAM | 2 KB | 2 KB | 2 KB | 4 KB (+100%) | 1 KB (-50%) |
| EEPROM | 1 KB | 1 KB | 1 KB | 2 KB (+100%) | 0.5 KB (-50%) |
| GPIO Count | 54 | 54 | 54 | 54 | 54 |
| 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 |
| picoPower Technology | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Integrated LCD controller eliminates external driver IC (vs ATMEGA328P-PU)
- 20 MHz maximum clock with 16 MIPS throughput (vs ATMEGA329-16AU)
- picoPower technology with deep sleep modes (vs ATMEGA3290P-20AU)
- 54 GPIO pins for richer peripheral connectivity (vs ATMEGA169P-20MN)
Design Notes
Estimated: at 20 MHz active mode with Vcc=5V, the ATMEGA329P-20MN typically draws 15-25 mA depending on peripheral activation; power-down mode drops to sub-1 uA. Use the SLEEP instruction and configure unused peripherals to power-down via PRR (Power Reduction Register) to minimize active current. Always measure actual current on the bench - datasheet typ numbers assume 25 C, 5V, and minimal peripheral activity. Add a 100 nF decoupling cap on each VCC pin plus 10 uF bulk near the MCU.
The 64-QFN package's exposed thermal pad MUST be soldered to the ground plane for both electrical performance and thermal dissipation. Microchip datasheet doc8162 specifies a recommended 64 thermal vias in the pad for best heat transfer. In a 4-layer PCB with 1 oz copper, theta_JA is approximately 28 C/W; at 25 mA active current and 5V supply (125 mW dissipation), junction rise above ambient is roughly 3.5 C - negligible, so heatsinking is unnecessary for this part.
Place a 100 nF ceramic decoupling capacitor within 3 mm of each VCC pin (multiple VCC pins on this 64-QFN). Add a single 10 uF bulk capacitor near the MCU. For the LCD segment outputs, route traces with 0.1-0.2 mm spacing from adjacent signal lines to minimize crosstalk on low-voltage LCD waveforms. The JTAG pins (PC2-PC5) should be routed to a 0.1 inch header for debug access; if unused, configure them as GPIO. The RESET pin needs a 10 kohm pullup to VCC and a 100 nF cap to ground for in-circuit programming reliability.
Do not confuse the ATMEGA329P (with P suffix for picoPower) with the older non-P ATMEGA329 (without low-power features) when ordering - they share the same datasheet family but have different power profiles. When migrating between QFN (MN) and TQFP (AU) packages, verify your PCB footprint matches - they are mechanically incompatible. The 64-QFN MN package does NOT have leads like TQFP, requiring different soldering profiles. Check the JTAG fuse (JTAGEN) is enabled for debug if your programmer cannot connect.
Compliance Information
RoHS compliant per Microchip product page. The ATMEGA329P-20MN is NOT AEC-Q100 qualified - use ATMEGA329P-20MNVAO or automotive variants like ATmega3290P-20AUR for production automotive. Halogen-free per Microchip packaging materials declaration.