ATMEGA48P-20AUR - 8-bit AVR MCU 4KB Flash 20MHz 32-TQFP | Microchip
MPN: ATMEGA48P-20AUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.1 | $3.10 |
| 10 | $2.86 | $28.60 |
| 100 | $2.55 | $255.00 |
| 500 | $2.28 | $1,140.00 |
| 1,000 | $2.05 | $2,050.00 |
ATMEGA48P-20AUR Overview
An 8-bit AVR microcontroller is a Harvard-architecture processor that executes most of its 131 instructions in a single clock cycle, sitting at the entry level of the ATmega family hierarchy below the ATmega88P, ATmega168P and ATmega328P. Microcontrollers of this class integrate CPU, program memory, data memory, timers and communication peripherals on one die, replacing multi-chip logic solutions in cost-sensitive embedded systems.
Key features include the picoPower technology set (idle, power-down and power-save sleep modes), three flexible timer/counters with compare modes, a 10-bit 6-channel ADC, and USART, SPI and two-wire (I2C) serial interfaces. The AVR enhanced RISC core with 32 general-purpose working registers is directly connected to the ALU, allowing two independent registers to be accessed in a single instruction executed in one clock cycle - the basis of the 1 MIPS/MHz efficiency rating.
The picoPower process technology minimizes static leakage, so battery-powered 5V designs can spend most of their life in power-down while retaining SRAM and register contents. The 20 MHz speed grade (-20) supports full-speed UART and fast PWM generation without prescaler compromises. In-system programmable Flash permits firmware updates on the final assembly via SPI.
Typical applications include industrial sensor nodes, motor control auxiliary boards, household appliances, and 5V legacy replacement designs where the ATMEGA48-20 family is already qualified. The device is also popular in hobby and Arduino-compatible boards via MiniCore support.
A key design consideration is that 4 KB Flash and 512 B SRAM fill quickly; use avr-gcc with -Os optimization and keep lookup tables in PROGMEM. Leave the -P (picoPower) suffix selection consistent across builds since some low-current characteristics differ from the non-P version.
This page adds value beyond the Microchip datasheet by synthesizing distributor pricing, six drop-in alternatives, and practical design notes in one AI-citable reference.
Drop-in alternatives for ATMEGA48P-20AUR — 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 ATMEGA48P-20AUR (same form factor and footprint) — differing in EEPROM, Package, SRAM, Flash Memory, Timers/Counters.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA48P-20AU
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA48-20AU
✅ Drop-In✓ In Stock
$1.6 / Unit
View Datasheet →ATMEGA48A-AU
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA88PA-AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.21 / Unit
View Datasheet →ATMEGA168PA-AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.98 / Unit
View Datasheet →ATMEGA328P-AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.85 / Unit
View Datasheet →ATMEGA48P-20AUR Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Maximum Clock Frequency | 20 MHz |
| Performance | Up to 20 MIPS at 20 MHz |
| Flash Memory | 4 KB (2K x 16) |
| EEPROM | 256 B |
| SRAM | 512 B |
| Supply Voltage Range | 4.5 V to 5.5 V |
| General Purpose I/O | 23 I/O lines |
| Timers/Counters | Three flexible timer/counters with compare modes |
| ADC | 10-bit, 6-channel |
| Serial Interfaces | USART, SPI, 2-wire (I2C-compatible) |
| Package | 32-TQFP (7x7 mm) |
| Life Cycle Stage | ACTIVE |
| Mounting Type | Surface Mount |
| Programming | In-System Programmable (ISP) Flash |
| Power Technology | picoPower low-power features with sleep modes |
ATMEGA48P-20AUR Pin Configuration
| Pin 1 | PD3 (INT1) — Port D bit 3 / External Interrupt 1 |
| Pin 2 | PD4 (XCK/T0) — Port D bit 4 / USART external clock / Timer0 clock input |
| Pin 3 | GND — Ground |
| Pin 4 | VCC — Digital supply voltage |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Digital supply voltage |
| Pin 7 | PB6 (XTAL1/TOSC1) — Port B bit 6 / Crystal oscillator pin 1 / Timer oscillator |
| Pin 8 | PB7 (XTAL2/TOSC2) — Port B bit 7 / Crystal oscillator pin 2 |
| Pin 9 | PD5 (T1) — Port D bit 5 / Timer1 external clock input |
| Pin 10 | PD6 (AIN0) — Port D bit 6 / Analog comparator positive input |
| Pin 11 | PD7 (AIN1) — Port D bit 7 / Analog comparator negative input |
| Pin 12 | PB0 (ICP1/CLKO) — Port B bit 0 / Timer1 input capture / System clock output |
| Pin 13 | PB1 (OC1A) — Port B bit 1 / Timer1 output compare A / PWM output |
| Pin 14 | PB2 (SS/OC1B) — Port B bit 2 / SPI slave select / Timer1 output compare B |
| Pin 15 | PB3 (MOSI/OC2A) — Port B bit 3 / SPI master output / Timer2 output compare A |
| Pin 16 | PB4 (MISO) — Port B bit 4 / SPI master input |
| Pin 17 | PB5 (SCK) — Port B bit 5 / SPI serial clock |
| Pin 18 | AVCC — ADC supply voltage (connect to VCC through low-pass filter) |
| Pin 19 | ADC6 — ADC input channel 6 |
| Pin 20 | AREF — Analog reference voltage for ADC |
| Pin 21 | GND — Ground |
| Pin 22 | ADC7 — ADC input channel 7 |
| Pin 23 | PC0 (ADC8) — Port C bit 0 / ADC input channel 8 |
| Pin 24 | PC1 (ADC9) — Port C bit 1 / ADC input channel 9 |
| Pin 25 | PC2 (ADC10) — Port C bit 2 / ADC input channel 10 |
| Pin 26 | PC3 (ADC11) — Port C bit 3 / ADC input channel 11 |
| Pin 27 | PC4 (ADC12/SDA) — Port C bit 4 / ADC channel 12 / I2C data |
| Pin 28 | PC5 (ADC13/SCL) — Port C bit 5 / ADC channel 13 / I2C clock |
| Pin 29 | PC6 (RESET) — Reset input (active low) |
| Pin 30 | PD0 (RXD) — Port D bit 0 / USART receive |
| Pin 31 | PD1 (TXD) — Port D bit 1 / USART transmit |
| Pin 32 | PD2 (INT0) — Port D bit 2 / External Interrupt 0 |
Typical Applications
ATMEGA48P-20AUR is suitable for 6 applications: Industrial Sensor Nodes, Home Appliance Control Panels, Motor Control Auxiliary Boards, Hobby and Arduino-Compatible Projects, Battery-Powered Metering Devices, Legacy 5V System Replacement Designs.
Industrial Sensor Nodes
The ATMEGA48P-20AUR fits industrial sensor acquisition nodes where a 10-bit ADC, USART and 20 MHz core cover signal capture and Modbus-style serial links at minimal BOM cost. Its 4.5-5.5V supply connects directly to industrial 5V rails without an LDO stage, and the picoPower sleep modes let battery-buffered nodes idle between sampling windows. With 23 GPIO lines, a single device can drive sensor enable lines, status LEDs and an SPI or I2C front-end simultaneously. Use the ADC with Vcc reference or AREF for ratiometric measurements, and store calibration constants in the 256 B EEPROM. Design consideration: 512 B SRAM restricts buffering, so stream samples over UART rather than accumulating arrays.
Recommended
Home Appliance Control Panels
Appliance user interfaces - button matrices, rotary encoders, LED segment displays and buzzers - are a classic ATmega48 use case. The three timer/counters generate PWM for LED dimming and buzzer tones while the 20 MHz core scans a 5x4 key matrix with software debouncing within milliseconds. The 5V-only supply matches the legacy 5V logic environment of appliance boards, and in-system programmable Flash lets firmware be updated on the production line via a 2x3 ISP header. The 256 B EEPROM persists user settings across power cycles. Because the 4 KB Flash supports only modest feature sets, reserve the ATMEGA88P or ATMEGA168P drop-in alternatives for models that later add communication or more menus.
Recommended
Motor Control Auxiliary Boards
For fans, pumps and small actuators, the ATMEGA48P-20AUR generates PWM drive signals via its 8-bit and 16-bit timer compare outputs and reads back speed or current through the 10-bit ADC. A typical arrangement uses Timer1 fast PWM at 20-30 kHz for inaudible fan drive, with the ADC sampling tachometer or shunt signals at reduced rate. The 4.5-5.5V supply tolerates 5V rail sag common in motor systems. Its role is usually supervisory rather than core inverter control; complex FOC needs more RAM and dedicated peripherals, so use ATmega parts like ATMEGA32M1 for those. Layout practice: keep the MCU ground star-connected away from motor power return paths to protect the ADC reference.
Recommended
Hobby and Arduino-Compatible Projects
The ATMEGA48P-20AUR is fully supported by the MiniCore Arduino hardware package, making it an economical entry point for DIY electronics, robotics prototypes and educational kits. In this role the chip typically runs a trimmed Arduino core compiled with avr-gcc -Os, using HardwareSerial on PD0/PD1, SPI on PB3-PB5, and I2C on PC4/PC5 for shields and modules. The 32-TQFP can be hand-soldered with a drag-soldering technique, and ISP programming requires only a USBasp programmer. Budget guidance: with 512 B SRAM, keep libraries minimal - SoftwareSerial and string-heavy sketches will exhaust RAM quickly; when they do, the pin-compatible ATMEGA328P-AU is a no-layout-change upgrade.
Recommended
Battery-Powered Metering Devices
picoPower technology makes the ATMEGA48P-20AUR appropriate for 5V battery or energy-harvesting metering products that spend most of their life asleep. The power-down and power-save modes retain SRAM while timers or watchdog wake the core periodically to take an ADC reading and update an LCD or serial output, then return to sleep. The 256 B EEPROM accumulates metered values across resets. Because the part is specified for 4.5-5.5V, use a 4xAA alkaline stack, 5V boost converter, or select the low-voltage ATMEGA48PV variant for lithium cells. Careful BOD configuration preserves both accuracy and battery life; disable BOD in sleep if regulation is guaranteed.
Recommended
Legacy 5V System Replacement Designs
The ATMEGA48P-20AUR is a common consolidation choice when replacing obsolete discrete logic, older OTP/EPROM MCUs or custom gate arrays in 5V industrial and automotive-adjacent legacy systems. Its direct 5V I/O eliminates level-shifting, and the 131-instruction AVR core reimplements state machines and timing logic in firmware with 20 MHz headroom. In-system programmable Flash supports field updates through the existing SPI or a spare UART, extending service life of installed equipment. The 32-TQFP footprint is small enough to fit legacy board cutouts, and all pin-compatible family members (48/88/168/328) share one PCB layout, so memory capacity can be re-specified per product variant without respinning the board.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48P-20AUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48P-20AU | ATMEGA48-20AU | ATMEGA88PA-AU | ATMEGA328P-AU |
|---|---|---|---|---|---|
| Package | 32-TQFP (7x7 mm) | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 4 KB | 4 KB | 4 KB | 8 KB | 32 KB |
| SRAM | 512 B | 512 B | 512 B | 1 KB | 2 KB |
| EEPROM | 256 B | 256 B | 256 B | 512 B | 1 KB |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V (PA low-power grade) | 1.8 V to 5.5 V |
| picoPower Technology | Yes (-P suffix) | Yes | No (standard power) | Yes (PA = low power) | Yes (P = picoPower) |
Key Differentiators
- Lowest-cost picoPower member of the pin-compatible ATmega TQFP-32 family (vs ATMEGA328P-AU)
- picoPower sleep architecture versus standard ATmega48 (vs ATMEGA48-20AU)
- 5V-only supply simplifies legacy integration (vs ATMEGA48A-AU)
Design Notes
Connect AVCC (pin 18) to VCC through a low-pass filter such as 10 uH in series with 100 nF to GND; never leave AVCC floating even if the ADC is unused. When using the ADC with AREF, decouple AREF (pin 20) with 100 nF to GND and never connect an external voltage source while the internal reference is selected, since this can short the internal reference amplifier. Estimated: at 20 MHz/5.5V the active supply current is in the low-mA class per the datasheet power charts - verify exact figures in the electrical characteristics tables for your voltage and clock configuration.
Place a 100 nF ceramic decoupling capacitor directly across each VCC/GND pin pair (pins 4/6 to 3/5) within 2 mm of the pins, plus a 4.7-10 uF bulk capacitor near the supply entry. Keep the crystal (PB6/PB7) traces short and surround them with a grounded guard ring; route them away from fast PWM outputs PB1/PB3. The 32-TQFP center thermal relief is a die-attach pad region - flood the area under the part with ground plane and use via stitching to reduce ground bounce between ADC and digital grounds.
The most frequent ATmega48 design error is ignoring the memory budget: 4 KB Flash and 512 B SRAM overflow quickly with C libraries. Monitor the linker map, place constant tables in PROGMEM, and reserve space for the ISP self-programming routines if a bootloader is planned (the ATmega48 has no factory bootloader). Second, RESET (PC6) must be pulled up (10k) if the pin is left as RESET; disabling RESET via fuse converts PC6 to I/O but permanently disables further ISP programming. Finally, set fuses consistently - the -P picoPower variant responds to the same fuse map as the standard ATmega48.
Compliance Information
Compliance status not explicitly stated in provided web data. Microchip lists this as an active part; confirm RoHS/REACH/lead-free status via Microchip's product environmental documentation before specifying.
