ATMEGA329P-20AN - 8-bit AVR MCU 32KB Flash 64-TQFP | Microchip
MPN: ATMEGA329P-20AN ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.63 | $4.63 |
| 10 | $4.18 | $41.80 |
| 100 | $3.71 | $371.00 |
| 500 | $3.32 | $1,660.00 |
| 1,000 | $2.95 | $2,950.00 |
ATMEGA329P-20AN Overview
An 8-bit AVR microcontroller (MCU) is a single-chip computer built around the AVR enhanced RISC architecture, an 8-bit register file architecture with single-cycle instruction execution and Harvard-style separate program/data buses. AVR MCUs sit within the broader category hierarchy of microcontrollers -> embedded processors -> semiconductors. The ATmega329P specifically targets LCD-rich applications, integrating an LCD controller and supporting peripherals including SPI, UART/USART, and USI communication interfaces.
Key differentiating features include 131 powerful instructions (most single-clock cycle execution), 32 x 8 general purpose working registers, fully static operation, an integrated LCD driver, 4 flexible timer/counters with compare modes, internal calibrated oscillator, and 6 software-selectable power-saving modes. The PicoPower technology provides ultra-low power consumption suitable for battery-backed applications.
Technical depth: The device uses a Harvard architecture with two-stage pipelining and supports in-system programming via SPI interface. Hardware multipliers are not included (typical for 8-bit AVR), but the 20 MHz clock with single-cycle instruction fetch achieves 20 MIPS, comparable to other mid-range ATmega parts. The integrated LCD controller supports up to 4x25 segments directly without external driver ICs.
Typical applications include metering and measurement equipment, portable medical devices, industrial control panels with LCD displays, consumer electronics with graphical user interfaces, automotive instrument clusters, and battery-powered data loggers. The wide 2.7V-5.5V input range enables direct operation from single-cell Li-ion or 3V coin cell batteries.
When designing with this part, allocate sufficient PCB area for the TQFP-64 footprint (14x14 mm with 0.8 mm pitch) and use the LCD segment pins as documented in the datasheet segment mapping tables. The internal 8 MHz RC oscillator can replace an external crystal in cost-sensitive designs.
This page synthesizes distributor pricing, drop-in compatible alternatives, and practical design notes for the ATMEGA329P-20AN, complementing the manufacturer datasheet with structured data not found on a single OEM page.
Drop-in alternatives for ATMEGA329P-20AN — 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-20AN (same form factor and footprint) — differing in Operating Temperature, Package, ADC, RoHS Status, Debug Interface.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA329P-20ANR
✅ Drop-In✓ In Stock
$4.3 / Unit
View Datasheet →ATMEGA329P-20AUR
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA329P-20MN
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.61 / Unit
View Datasheet →ATMEGA329P-20MNR
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA329P-20AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$4.71 / Unit
View Datasheet →ATMEGA325P-20AUR
✅ Drop-In✓ In Stock
$4.11 / Unit
View Datasheet →ATMEGA329P-20AN Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Program Memory (Flash) | 32 KB |
| SRAM | 2 KB |
| EEPROM | 1 KB |
| Maximum CPU Speed | 20 MHz (20 MIPS) |
| Supply Voltage (Vcc) | 2.7 V to 5.5 V |
| Operating Temperature | -40C to +105C |
| Package | 64-pin TQFP (14x14 mm, 0.8 mm pitch) |
| Communication Interfaces | SPI, UART/USART, USI |
| LCD Controller | Integrated (supports up to 4x25 segments) |
| Timers/Counters | 4 (with compare modes, PWM) |
| Instruction Set | 131 instructions, most single-cycle |
| Power-Saving Modes | 6 software-selectable modes |
| In-System Programming | Yes (SPI-based ISP) |
| RoHS Status | Compliant (Green) |
| Mounting Type | Surface Mount |
ATMEGA329P-20AN 64-pin tqfp (14x14 mm, 0.8 mm pitch) Pin Configuration Guide
Pin configuration for ATMEGA329P-20AN (64-pin tqfp (14x14 mm, 0.8 mm pitch) 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 ATMEGA329P-20AN.
Refer to the datasheet for full pin configuration.
Typical Applications
ATMEGA329P-20AN is suitable for 6 applications: Industrial Metering with LCD Display, Portable Medical Monitoring Devices, Consumer Electronics HMI with Graphical LCD, Automotive Instrument Cluster Auxiliary Display, Battery-Powered Data Loggers, HVAC Control Panels.
Industrial Metering with LCD Display
The ATMEGA329P-20AN is purpose-built for industrial metering applications where an integrated LCD controller eliminates the need for an external driver IC, reducing BOM cost and PCB area. Its 32 KB Flash stores calibration tables and Modbus/RTU communication stacks, while the 2 KB SRAM handles real-time measurement buffers. The integrated LCD driver supports up to 4x25 segments, sufficient for electricity meters displaying kWh, voltage, current, and power factor across multiple display modes. The 2.7-5.5 V input range allows direct connection to rectified mains-derived supplies. The 6 power-saving modes enable battery-backed metering designs where the MCU wakes periodically to log consumption and update the LCD while consuming minimal quiescent current. The 105C temperature grade supports outdoor enclosure installations.
Recommended
Portable Medical Monitoring Devices
Battery-powered portable medical devices benefit from the ATMEGA329P-20AN's PicoPower technology and integrated LCD controller for direct patient-data display without external drivers. The 20 MIPS throughput executes lightweight signal-processing algorithms for pulse oximetry or blood-pressure trending in real time. The 1 KB EEPROM stores patient calibration data and usage history with 100K+ write endurance. The 105C operating range accommodates sterilizable handheld instrument housings. SPI and UART/USART interfaces connect to wireless modules for telemetry. The 6 power-saving modes are critical for extending battery life across multi-shift clinical workflows, where the device must remain in low-power standby between measurements.
Recommended
Consumer Electronics HMI with Graphical LCD
Consumer appliances such as coffee machines, microwave ovens, and washing machines use the ATMEGA329P-20AN for its integrated 4x25-segment LCD driver and cost-effective TQFP-64 footprint. The 32 KB Flash stores multi-language UI strings and cooking-cycle firmware, while 2 KB SRAM buffers user input and sensor data. The 20 MHz CPU speed handles capacitive-touch key scanning and encoder input in real time without missing events. The USI interface connects to additional sensor ICs for temperature, humidity, or weight measurement. The wide 2.7-5.5 V supply tolerates rectified mains-derived rails without additional regulation. The industrial 105C temperature rating ensures reliability behind oven doors and dishwasher panels.
Recommended
Automotive Instrument Cluster Auxiliary Display
Within non-safety-critical automotive auxiliary displays (climate control, audio head units, trip computer secondary readouts), the ATMEGA329P-20AN provides a low-cost display controller with integrated segment LCD driver. The 105C temperature grade handles under-dash thermal environments. The 32 KB Flash supports CAN-readable OBD-II parsing routines and display update logic. The 2 KB SRAM maintains scrolling message buffers for HVAC status. SPI connectivity interfaces with the main cluster MCU for command reception. While not AEC-Q100 qualified, the device finds application in aftermarket and lower-tier OEM auxiliary displays where the integrated LCD controller eliminates a dedicated display-driver IC and reduces overall BOM cost by 15-25%.
Recommended
Battery-Powered Data Loggers
Long-life remote data loggers benefit from the ATMEGA329P-20AN's combination of 32 KB Flash, 1 KB EEPROM (with 100K+ endurance), and 6 power-saving modes. The MCU wakes from power-down mode via watchdog timer interrupt, samples sensors via ADC, writes timestamped data to EEPROM, and returns to sleep, achieving average current draw below 10 microamps in many use cases. The integrated LCD allows field engineers to view recent readings without external display modules. The wide 2.7-5.5 V supply tolerates battery voltage droop across discharge cycles. Applications include environmental monitoring stations, agricultural soil sensors, cold-chain temperature loggers, and structural health monitoring nodes where battery replacement intervals of 1-5 years are required.
Recommended
HVAC Control Panels
Commercial and residential HVAC control panels use the ATMEGA329P-20AN for its integrated LCD segment driver and reliable 20 MHz AVR core for thermostat loop control. The 32 KB Flash stores multi-stage heating/cooling algorithms, schedule definitions, and communication protocol stacks. The 4 timer/counters with PWM generate control signals for damper actuators and three-speed fan control. UART/USART interfaces connect to modulating furnace controllers and external communication modules. The 105C temperature rating supports plenum-mounted installations where ambient temperatures regularly exceed 70C. The integrated LCD eliminates external driver ICs in displays showing setpoint, current temperature, fan mode, and scheduling icons, reducing controller BOM cost by approximately 20-30% versus designs requiring a separate HT1621 or similar segment driver.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA329P-20AN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA329P-20ANR | ATMEGA329P-20AUR | ATMEGA329P-20AU | ATMEGA325P-20AU |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 64-pin TQFP (14x14 mm) | 64-pin TQFP (14x14 mm) - same | 64-pin TQFP (14x14 mm) - same | 64-pin TQFP (14x14 mm) - same | 64-pin TQFP - same family |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| Max CPU Speed | 20 MHz (20 MIPS) | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating Temperature | -40C to +105C | -40C to +105C | -40C to +85C | -40C to +85C | -40C to +85C |
| 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 | 1.8 V to 5.5 V (wider) |
| LCD Controller | Yes (integrated, 4x25 segments) | Yes | Yes | Yes | Yes |
| Connectivity | SPI, UART/USART, USI | SPI, UART/USART, USI | SPI, UART/USART, USI | SPI, UART/USART, USI | SPI, UART/USART (no USI) |
Key Differentiators
- Integrated LCD controller eliminates external display driver IC (vs ATMEGA328P-PU)
- PicoPower technology extends battery life (vs ATMEGA329-16AU)
- Wider 105C operating temperature versus 85C industrial grade (vs ATMEGA329P-20AUR)
Design Notes
The 64-pin TQFP package has 0.8 mm lead pitch and 14x14 mm body size. Route traces between pads with 0.2 mm trace width and 0.2 mm clearance to maintain manufacturability at standard PCB fabricators. Use 0.1 uF ceramic decoupling capacitors as close as possible to each VCC/AVCC pin pair, plus a single 10 uF bulk capacitor near the device. Place the ISP header (2x3 or 1x6) on the PCB edge for in-system programming access without disassembling the product enclosure. The exposed pad on the TQFP is the thermal/ground pad - connect to ground plane with multiple thermal vias for optimal heat dissipation at 20 MHz operation.
For battery-powered designs, leverage the 6 power-saving modes (Idle, ADC Noise Reduction, Power-down, Power-save, Standby, Extended Standby) to achieve average current below 50 uA in typical data-acquisition applications. Disable unused peripherals by clearing their PRR (Power Reduction Register) bits to reduce active current by 15-25%. The brown-out detector (BOD) consumes approximately 20 uA continuously; disable BOD during sleep periods using the BOD disable fuse and rely on the watchdog timer for wake-up. Use the internal 8 MHz RC oscillator instead of an external crystal to reduce sleep current by 1-2 mA in applications tolerant of the +/- 10% frequency accuracy.
The 'P' suffix denotes PicoPower variants with different sleep current specifications versus the legacy non-P versions (e.g., ATmega329 versus ATmega329P). Verify the exact part number when migrating legacy designs to ensure the lower-power PicoPower characteristics are realized. The ISP programming interface uses the SCK/MISO/MOSI/RESET pins; if these are repurposed in the application, ensure they remain accessible for ISP via jumper or test pad access. Fuses must be configured carefully - an improperly programmed fuse (especially the clock source fuse) can lock the device, requiring high-voltage parallel programming to recover.
The integrated LCD controller drives segment outputs up to 4x25 (100 segments total). Connect LCD segment and common pins through 1k-100k bias resistors to set contrast and limit segment switching current. Place the LCD bias generation capacitors (typically 100 nF to 1 uF) close to the LCD pins with short traces to minimize display artifacts. Avoid routing high-frequency digital signals (SPI clock above 5 MHz, USART at high baud rates) adjacent to LCD segment traces to prevent display ghosting. Use the LCD Enable (LCDEN) bit in the LCD control register to completely power down the LCD during deep-sleep modes for additional current savings.
Compliance Information
RoHS compliant Green compound per Microchip product page. Not AEC-Q100 qualified; for automotive applications requiring formal AEC-Q100, consider ATMEGA329P-20MNR or a dedicated automotive-grade MCU.
