ATMEGA48P-20MMU - 4KB Flash 20MHz AVR MCU QFN-28 | Microchip
MPN: ATMEGA48P-20MMU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.68 | $0.68 |
| 10 | $0.52 | $5.20 |
| 100 | $0.35 | $35.00 |
| 500 | $0.24 | $120.00 |
| 1,000 | $0.1698 | $169.80 |
ATMEGA48P-20MMU Overview
A microcontroller (MCU) is a single-chip computer integrating a processor core, program memory, data memory, and peripherals such as timers, communication interfaces, and analog-to-digital converters. Within the semiconductor hierarchy, the ATmega48P belongs to the AVR family of 8-bit RISC MCUs, positioned under the broader categories of embedded processors and system-on-chip devices.
Key differentiating features include the advanced AVR RISC architecture with 131 powerful instructions, most executing in a single clock cycle; 32 general-purpose 8-bit working registers; three flexible timer/counters with compare modes; and an on-chip 10-bit ADC. Serial peripherals include SPI, TWI (I2C-compatible), and USART for communication with sensors, displays, and other ICs.
The picoPower technology of the P-grade silicon reduces power consumption in idle, power-down, and power-save modes, making the device suitable for battery-backed and always-on embedded designs. In-system programmable (ISP) Flash and support for In-Circuit Serial Programming (ICSP) via debuggers such as the MPLAB SNAP allow firmware updates without removing the chip from the PCB.
Typical applications include industrial control nodes, consumer appliance interfaces, sensor acquisition front ends, and hobby or education embedded platforms. Microchip notes that a newer picoPower device, the ATmega48PA, is available and should be considered for new designs, but the ATmega48P remains an active lifecycle product for existing BOMs.
A key design consideration: the 4.5 V to 5.5 V operating range of the P grade differs from wider-range A/PA grades, so verify supply rails before substituting. This page synthesizes verified distributor pricing, drop-in alternatives, and design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA48P-20MMU 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 ATMEGA48P-20MMU (same form factor and footprint) β differing in Package, ADC, RoHS Status, Flash Memory, Maximum Clock Frequency.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA48P-20MMUR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA48PA-20MMU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA48-20MMU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA88PA-20MMU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA168PA-20MMU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA48P-20MMU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Clock Speed | 20 MHz |
| Flash Memory | 4 KB (2K x 16) ISP Flash |
| EEPROM | 256 B |
| SRAM | 512 B |
| Supply Voltage | 4.5 V to 5.5 V |
| I/O Ports | 23 general-purpose I/O lines |
| Working Registers | 32 x 8-bit general purpose |
| Timer/Counters | 3 flexible timer/counters with compare modes |
| Serial Interfaces | SPI, TWI, USART |
| ADC | 10-bit ADC |
| Low Power Technology | picoPower |
| Programming | ISP / ICSP in-system programming |
| Package | 28-VQFN (4x4 mm), 0.45 mm pitch, 1 mm height |
| Package Material | Green (RoHS) plastic |
| Mounting Type | Surface Mount |
| Lifecycle Stage | ACTIVE |
ATMEGA48P-20MMU Pin Configuration
| Pin 1 | PC6 (RESET) β Reset input / I/O pin |
| Pin 2 | PD0 (RXD) β USART receive / I/O |
| Pin 3 | PD1 (TXD) β USART transmit / I/O |
| Pin 4 | PD2 (INT0) β External interrupt 0 / I/O |
| Pin 5 | PD3 (INT1) β External interrupt 1 / I/O |
| Pin 6 | PD4 (XCK/T0) β USART clock / Timer0 clock / I/O |
| Pin 7 | VCC β Digital supply voltage (4.5 V to 5.5 V) |
| Pin 8 | GND β Ground |
| Pin 9 | PB6 (XTAL1/TOSC1) β Crystal oscillator input / I/O |
| Pin 10 | PB7 (XTAL2/TOSC2) β Crystal oscillator output / I/O |
| Pin 11 | PD5 (T1) β Timer1 counter input / I/O |
| Pin 12 | PD6 (AIN0) β Analog comparator positive input / I/O |
| Pin 13 | PD7 (AIN1) β Analog comparator negative input / I/O |
| Pin 14 | PB0 (ICP1/CLKO) β Timer1 input capture / clock output / I/O |
| Pin 15 | PB1 (OC1A) β Timer1 PWM output A / I/O |
| Pin 16 | PB2 (SS/OC1B) β SPI slave select / Timer1 PWM output B / I/O |
| Pin 17 | PB3 (MOSI/OC2A) β SPI master output / Timer2 PWM output / I/O |
| Pin 18 | PB4 (MISO) β SPI master input / I/O |
| Pin 19 | PB5 (SCK) β SPI serial clock / I/O |
| Pin 20 | AVCC β ADC supply voltage |
| Pin 21 | AREF β ADC analog reference input |
| Pin 22 | GND β Ground |
| Pin 23 | PC0 (ADC0) β ADC input 0 / I/O |
| Pin 24 | PC1 (ADC1) β ADC input 1 / I/O |
| Pin 25 | PC2 (ADC2) β ADC input 2 / I/O |
| Pin 26 | PC3 (ADC3) β ADC input 3 / I/O |
| Pin 27 | PC4 (ADC4/SDA) β ADC input 4 / TWI data / I/O |
| Pin 28 | PC5 (ADC5/SCL) β ADC input 5 / TWI clock / I/O |
Typical Applications
ATMEGA48P-20MMU is suitable for 6 applications: Industrial Control Nodes, Consumer Appliance Interfaces, Sensor Acquisition Front Ends, Motor Control and PWM Drives, Embedded Education and Prototyping, Battery-Backed Backup and Monitoring Systems.
Industrial Control Nodes
The ATMEGA48P-20MMU fits industrial control and monitoring nodes where a 5 V logic rail is standard and robust, deterministic 8-bit control is sufficient. Its 20 MHz AVR core delivers up to 20 MIPS for polling sensors, driving relays, and running simple state machines, while the 10-bit ADC digitizes analog process variables such as temperature or level. SPI and TWI interfaces connect the MCU to isolated I/O expanders, RTCs, and EEPROMs. The picoPower feature set cuts standby consumption in power-save mode, valuable for nodes that wake periodically. The 4 KB Flash is adequate for compact control firmware, and ICSP allows field firmware updates without desoldering the VQFN package.
Recommended
Consumer Appliance Interfaces
In consumer appliances such as coffee makers, fans, and small heating devices, the ATMEGA48P-20MMU provides cost-effective user-interface control: scanning keypads, driving LEDs or segment displays, and managing buzzer feedback. The 23 GPIO lines cover button matrices and indicator outputs without external logic, and the three timer/counters generate PWM for motor or heater control with hardware precision. Operating from the appliance's 5 V rail eliminates level shifting. The 256 B EEPROM retains user settings and fault logs across power cycles. The 4x4 mm VQFN package keeps the controller PCB footprint minimal inside compact appliance housings, and green/RoHS packaging aligns with consumer environmental requirements.
Recommended
Sensor Acquisition Front Ends
The ATMEGA48P-20MMU serves as a compact sensor acquisition controller, using its on-chip 10-bit ADC to digitize up to six external channels alongside the internal temperature sensor. For applications needing higher resolution, the SPI port interfaces external delta-sigma ADCs while the MCU handles filtering, scaling, and reporting. The 512 B SRAM buffers sample windows for averaging or peak detection, and the USART streams results to a host or radio module. Timer-based sampling provides jitter-free conversion timing. Because the picoPower silicon supports power-down modes with interrupt wake, battery-backed sensor nodes can duty-cycle the 20 MHz core aggressively, waking only on timer expiry or external interrupt events.
Recommended
Motor Control and PWM Drives
Small DC motor and fan control circuits benefit from the ATMEGA48P-20MMU's three timer/counters, which generate multiple hardware PWM channels without CPU intervention - one 16-bit timer provides high-resolution phase-correct PWM while 8-bit timers handle auxiliary channels. The MCU reads tachometer feedback through interrupt pins or the ADC, closes a speed loop in firmware, and drives a MOSFET gate driver through the PWM output. At 20 MHz, control loop rates of several kHz are comfortably achieved. The 5 V supply directly drives logic-level gate driver ICs. The 4 KB Flash accommodates PID control code, and the VQFN-28 footprint suits compact driver boards integrated into the motor housing.
Recommended
Embedded Education and Prototyping
The ATMEGA48P-20MMU is a staple of embedded-systems education and prototyping because the AVR architecture is well documented, tools are free (AVR-GCC, Microchip Studio, MiniCore Arduino support), and ICSP programming requires only a low-cost programmer such as the MPLAB SNAP. Students learn bare-metal register programming on the same 28-pin VQFN footprint used from ATmega48 through ATmega328, enabling migration exercises as code grows. The 20 MHz clock, 10-bit ADC, and full SPI/TWI/USART set cover classic lab exercises: blinky, PWM, ADC sampling, and serial communication. Breadboard adapters for the 4x4 mm QFN make the part accessible without dedicated PCBs early in a project.
Recommended
Battery-Backed Backup and Monitoring Systems
In monitoring units that must remain alive during mains outages - utility meters, alarm panels, data loggers - the ATMEGA48P-20MMU's picoPower modes extend backup-battery runtime by placing the core in power-down between periodic wake-ups. The asynchronous timer keeps a low-frequency clock running in sleep for accurate timekeeping, and pin-change interrupts wake the MCU on external events. EEPROM stores tamper and event logs across resets. The MCU supervises battery voltage through the ADC and signals low-battery conditions via USART or GPIO to a supervisory circuit. At 5 V systems with a 9 V or lead-acid backup source and a small regulator, the 4x4 mm VQFN controller keeps total standby drain in the microamp range.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48P-20MMU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48P-20MMUR | ATMEGA48PA-20MMU | ATMEGA48-20MMU | ATMEGA88PA-20MMU | ATMEGA168PA-20MMU |
|---|---|---|---|---|---|---|
| Package | 28-VQFN (4x4 mm) | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 4 KB | 4 KB | 4 KB | 4 KB | 8 KB | 16 KB |
| SRAM | 512 B | 512 B | 512 B | 512 B | 1 KB | 1 KB |
| EEPROM | 256 B | 256 B | 256 B | 256 B | 512 B | 512 B |
| Max Clock Speed | 20 MHz | 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 | wider range (1.8 V capable grade) | 4.5 V to 5.5 V | wider range (1.8 V capable grade) | wider range (1.8 V capable grade) |
| Low Power Grade | picoPower (P) | picoPower (P) | picoPower (PA, newer) | standard (non-picoPower) | picoPower (PA) | picoPower (PA) |
Key Differentiators
- picoPower grade at P-grade price (vs ATMEGA48-20MMU)
- Drop-in memory upgrade path (vs ATMEGA88PA-20MMU / ATMEGA168PA-20MMU)
- Cost per unit (vs ATMEGA48PA-20MMU)
Design Notes
The ATMEGA48P-20MMU is specified from 4.5 V to 5.5 V; do not use it on 3.3 V rails - that requires the ATmega48PA or ATmega48A grade. Decouple VCC (pin 7) and AVCC (pin 20) with 100 nF ceramic capacitors placed within 2 mm of each pin, plus 10 uF bulk capacitance at the board level. AVCC must be connected even if the ADC is unused. Estimated: a 20 MHz active core draws roughly 5-6 mA at 5 V (verify against the datasheet electrical characteristics table for your conditions), so size the 5 V regulator accordingly for the full GPIO load.
The 28-VQFN (4x4 mm) package has a 0.45 mm pin pitch - design the land pattern per the Microchip QFN-4x4 datasheet drawing and inspect stencil apertures for the fine pitch. Connect the exposed pad (if used on your variant) to ground for mechanical reliability. For ICSP, route RESET (pin 1), MOSI (17), MISO (18), and SCK (19) to a 2x3 header, keeping traces short and adding 100 ohm series resistors on SCK/MOSI if in-system programming shares these lines with SPI peripherals. Keep the XTAL1/XTAL2 crystal traces (pins 9-10) under 10 mm with guard ground.
Three common pitfalls when using this part: (1) Microchip officially designates the ATmega48PA as the newer device - new designs should justify selecting the P grade, and any substitution must re-verify fuse settings, since the extended fuse bits differ between grades and wrong fuse settings can disable RESET or select an invalid clock source. (2) PC6 is RESET by default (RSTDISBL fuse); do not casually reprogram it as I/O or you lose ICSP access. (3) The P grade is 5 V-only - connecting it to a 3.3 V system risks out-of-spec operation and unreliable clock margins.
Compliance Information
Package described as GREEN plastic in the verified datasheet specifications, indicating RoHS-compliant lead-free green packaging. REACH, halogen-free, and conflict minerals status not stated in provided data.
