ATMEGA48PB-MU - 8-bit AVR MCU 4KB Flash 20MHz QFN-32 | Microchip
MPN: ATMEGA48PB-MU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.62 | $1.62 |
| 10 | $1.45 | $14.50 |
| 100 | $1.24 | $124.00 |
| 500 | $1.08 | $540.00 |
| 1,000 | $0.94 | $940.00 |
ATMEGA48PB-MU Overview
An 8-bit AVR microcontroller is a single-chip processor built on the AVR enhanced RISC architecture, in which most instructions execute in a single clock cycle. Within the power-management hierarchy, an MCU such as the ATmega48PB combines the processor core, program memory (Flash), data memory (SRAM), non-volatile storage (EEPROM), timers, communication peripherals, and analog-to-digital conversion into one semiconductor device, eliminating the need for external support chips in many applications.
Key features include 27 general-purpose I/O lines, 32 general-purpose working registers, three flexible timer/counters with compare modes, internal and external interrupt sources, and a USART with wake-up on start of transmission. The picoPower technology enables very low sleep-mode consumption, important for battery-powered products. Flash supports read-while-write operation for in-system programming and self-programming.
Technical depth: the AVR core executes powerful instructions mostly in one cycle, achieving throughput close to 1 MIPS per MHz at 20 MHz. Peripherals include byte-oriented Two-Wire Interface (I2C-compatible), SPI serial port, and the 10-bit ADC referenced to AVCC or an internal reference. The PB suffix denotes the latest silicon revision of the ATmega48P family, adding improved pin functionality (notably on pins 3 and 6) while remaining largely software-compatible with ATmega48PA designs.
Typical applications include industrial sensor nodes, battery-powered metering, consumer appliance control, HVAC and lighting control, and low-cost IoT endpoints where the 32-pad QFN footprint and 1.8V operation reduce board area and power budget.
Design consideration: the QFN package exposes a die-attach pad beneath the device; connect it to a grounded copper pour for both thermal relief and signal integrity, and follow Microchip application guidance on decoupling VCC and AVCC separately.
This page synthesizes distributor pricing tiers, drop-in alternatives, pinout data, and practical design notes not found together on the manufacturer datasheet, providing an information-gain resource for engineers and buyers.
Drop-in alternatives for ATMEGA48PB-MU — 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 ATMEGA48PB-MU (same form factor and footprint) — differing in Package, Communication Interfaces, Operating Temperature, Timers/Counters, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA48PB-AUR
✅ Drop-In✓ In Stock
$0.39 / Unit
View Datasheet →ATMEGA48PB-AN
✅ Drop-In✓ In Stock
$0.42 / Unit
View Datasheet →ATMEGA88PB-MU
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA168PB-MU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.31 / Unit
View Datasheet →ATMEGA328PB-MU
✅ Drop-In✓ In Stock
$1.19 / Unit
View Datasheet →ATMEGA48PA-MUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.98 / Unit
View Datasheet →ATMEGA48PB-MU Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Program Memory (Flash) | 4 KB (2K x 16) |
| EEPROM | 256 B |
| SRAM | 512 B |
| Maximum CPU Frequency | 20 MHz |
| Supply Voltage Range | 1.8 V to 5.5 V |
| General Purpose I/O | 27 lines |
| ADC Resolution | 10-bit, 8 channels |
| Timers/Counters | 3 (with compare modes) |
| Communication Interfaces | USART, SPI, Two-Wire Interface (I2C-compatible) |
| Low Power Technology | picoPower |
| Operating Temperature | -40 C to +85 C |
| Package | 32-VFQFN (5x5 mm) |
| Mounting Type | Surface Mount |
| Working Registers | 32 x 8-bit |
| In-System Programming | Yes (ISP, read-while-write) |
| Functional Safety Support | Yes (FuSa class per DigiKey listing) |
| RoHS Status | Compliant (green package) |
ATMEGA48PB-MU Pin Configuration
| Pin 1 | PD3 — Port D bit 3 / PCINT19 / OC2B / INT1 |
| Pin 2 | PD4 — Port D bit 4 / PCINT20 / XCK / T0 |
| Pin 3 | GND — Ground (see PB migration caution on pin usage) |
| Pin 4 | VCC — Digital supply voltage |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Digital supply voltage (see PB migration caution on pin usage) |
| Pin 7 | PB6 — Port B bit 6 / PCINT6 / XTAL1 / TOSC1 |
| Pin 8 | PB7 — Port B bit 7 / PCINT7 / XTAL2 / TOSC2 |
| Pin 9 | PD5 — Port D bit 5 / PCINT21 / OC0B / T1 |
| Pin 10 | PD6 — Port D bit 6 / PCINT22 / OC0A / AIN0 |
| Pin 11 | PD7 — Port D bit 7 / PCINT23 / AIN1 |
| Pin 12 | PB0 — Port B bit 0 / PCINT0 / ICP1 / CLKO |
| Pin 13 | PB1 — Port B bit 1 / PCINT1 / OC1A |
| Pin 14 | PB2 — Port B bit 2 / PCINT2 / SS / OC1B |
| Pin 15 | PB3 — Port B bit 3 / PCINT3 / MOSI / OC2A |
| Pin 16 | PB4 — Port B bit 4 / PCINT4 / MISO |
| Pin 17 | PB5 — Port B bit 5 / PCINT5 / SCK |
| Pin 18 | AVCC — ADC supply voltage |
| Pin 19 | ADC6 — ADC input channel 6 |
| Pin 20 | AREF — Analog reference voltage |
| Pin 21 | GND — Ground |
| Pin 22 | ADC7 — ADC input channel 7 |
| Pin 23 | PC0 — Port C bit 0 / PCINT8 / ADC0 |
| Pin 24 | PC1 — Port C bit 1 / PCINT9 / ADC1 |
| Pin 25 | PC2 — Port C bit 2 / PCINT10 / ADC2 |
| Pin 26 | PC3 — Port C bit 3 / PCINT11 / ADC3 |
| Pin 27 | PC4 — Port C bit 4 / PCINT12 / ADC4 / SDA |
| Pin 28 | PC5 — Port C bit 5 / PCINT13 / ADC5 / SCL |
| Pin 29 | PC6 — Port C bit 6 / PCINT14 / RESET |
| Pin 30 | PD0 — Port D bit 0 / PCINT16 / RXD |
| Pin 31 | PD1 — Port D bit 1 / PCINT17 / TXD |
| Pin 32 | PD2 — Port D bit 2 / PCINT18 / INT0 |
Typical Applications
ATMEGA48PB-MU is suitable for 6 applications: Industrial Sensor Nodes, Battery-Powered Metering, Consumer Appliance Control, HVAC and Lighting Control, Low-Cost IoT Endpoints, Human Interface Devices and Accessories.
Industrial Sensor Nodes
The ATMEGA48PB-MU fits industrial sensor nodes because its 8-channel 10-bit ADC directly digitizes analog sensors without an external converter, and its 1.8V to 5.5V supply range tolerates noisy industrial rails. The 27 GPIO lines interface switches, relays, and status LEDs, while the USART and Two-Wire Interface connect to field buses and displays. Placed on a 5x5 mm QFN footprint, the controller reduces PCB area on dense IO modules. The -40C to +85C operating range covers typical factory-floor enclosures, and picoPower sleep modes let the node duty-cycle its sampling to extend battery backup life during power loss.
Recommended
Battery-Powered Metering
For battery-powered metering such as water, heat, or energy counters, the ATMEGA48PB-MU's picoPower technology minimizes sleep-mode current, which dominates the energy budget when the device wakes briefly to sample. The 1.8V minimum supply allows operation directly from a lithium coin cell through most of its discharge curve, and the 10-bit ADC reads shunt or divider measurements. The 256B EEPROM stores calibration and cumulative counters that survive power removal. Running the 20 MHz-capable core at lower clock frequencies trades throughput for further current savings, and the USART wake-on-start-of-transmission feature supports periodic data upload without constant polling.
Recommended
Consumer Appliance Control
White-goods and small-appliance control boards benefit from the ATMEGA48PB-MU's combination of three timer/counters with compare modes for PWM-driven loads such as fan motors, heaters, and lamp dimming, plus 27 GPIO for buttons, encoders, and indicators. The byte-oriented Two-Wire Interface (I2C-compatible) reads temperature and humidity sensors, and the internal oscillator eliminates an external crystal in non-timing-critical designs, saving cost. The 4KB Flash is sufficient for state-machine control logic, and the green RoHS QFN package meets consumer environmental requirements. Its 20 MHz performance handles UI debounce and control loops with large margins.
Recommended
HVAC and Lighting Control
In HVAC thermostats and lighting controllers, the ATMEGA48PB-MU provides PWM outputs from its timer/counter compare modes to drive triac gating or LED dimming stages, while the 10-bit ADC samples NTC thermistors and potentiometers for closed-loop temperature control. The picoPower modes keep standby draw negligible between thermostat wake events, extending battery life in wireless wall units. The USART connects to RS-485 transceivers for networked building automation, and the Two-Wire Interface reads humidity and CO2 sensors. The 5x5 mm QFN package fits compact wall-plate form factors where board area is constrained.
Recommended
Low-Cost IoT Endpoints
As an IoT endpoint MCU, the ATMEGA48PB-MU drives sub-GHz or Bluetooth LE radio modules over USART or SPI, forwarding ADC-sampled sensor data while consuming minimal sleep current thanks to picoPower technology. The 4KB Flash accommodates a lightweight protocol stack when written in optimized C, and the USART wake-on-start-of-transmission supports event-driven radio wake-up. Operating down to 1.8V allows direct connection to single-cell supplies without a boost converter in some designs. Community tooling, including the MCUdude MiniCore Arduino package, accelerates firmware development, making this part popular for cost-driven sensor-to-cloud nodes.
Recommended
Human Interface Devices and Accessories
Keypads, remote controls, small displays, and accessory controllers use the ATMEGA48PB-MU for its ample GPIO, interrupt-on-pin-change capability for wake-on-keypress, and internal oscillator that removes crystal cost. Timer compare modes generate backlight PWM and buzzer tones, while the Two-Wire Interface drives character LCDs and capacitance touch controllers. The 5x5 mm QFN suits thin accessory housings, and the industrial -40C to +85C rating covers automotive cabin accessory use. Firmware in 4KB Flash handles matrix scanning, debouncing, and LED management comfortably, and the ADC supports battery-level monitoring for rechargeable accessories.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48PB-MU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48PB-AUR | ATMEGA88PB-MU | ATMEGA168PB-MU | ATMEGA328PB-MU | ATMEGA48PA-MUR |
|---|---|---|---|---|---|---|
| Package | 32-VFQFN (5x5 mm) | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 4 KB | 4 KB | 8 KB | 16 KB | 32 KB | 4 KB |
| SRAM | 512 B | 512 B | 1 KB | 1 KB | 2 KB | 512 B |
| EEPROM | 256 B | 256 B | 512 B | 512 B | 1 KB | 256 B |
| Max CPU Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Timers | 3 | 3 | 3 | 3 | 5 (plus extra UART) | 3 |
Key Differentiators
- Lowest cost within the pin-compatible PB family (vs ATMEGA328PB-MU)
- Automotive-qualified upgrade on the same die (vs ATMEGA48PB-AUR)
- Newer PB silicon vs PA predecessor (vs ATMEGA48PA-MUR)
- Memory headroom trade-off (vs ATMEGA88PB-MU)
Design Notes
The 32-VFQFN package includes a central die-attach pad. Create an exposed-pad land pattern with an array of thermal vias (typically 4-9) tied to the ground plane, and connect the pad to GND for reliable thermal and electrical performance. Standard QFN assembly requires stencil apertures of roughly 50-70% pad coverage to prevent voiding and tombstoning. Follow IPC-recommended QFN footprint guidelines and verify reflow profile for lead-free solder paste.
Decouple each VCC pin (pins 4 and 6) with a 100 nF ceramic capacitor placed within a few millimeters of the pin, plus one bulk 4.7-10 uF capacitor per board. Supply AVCC (pin 18) from VCC through an LC filter (for example 10 uH and 100 nF) or directly with a dedicated 100 nF capacitor for cleaner ADC reference operation. Keep analog routing away from USART and PWM switching lines to protect the 10-bit ADC's effective resolution.
When migrating from ATMEGA48PA/ATMEGA48A, Microchip documentation adds modified pin functionality on the PB revision: pin 3 must not be actively driven if connected to GND and ACO must not be enabled there, and pin 6 must not be actively driven if connected to VCC. Also remember RESET (pin 29, PC6) defaults to its reset function - external pull-up of about 10 kiloohm is recommended, and debugWIRE shares this pin, which affects one-wire programming layouts.
For crystal operation, place the crystal and its load capacitors (typically 12-22 pF, per crystal specification) directly adjacent to PB6/PB7 with short, guarded traces. If using the internal 8 MHz RC oscillator, PB6/PB7 are freed as GPIO, saving two pins. Route the ADC reference (AREF) as a quiet node with its own 100 nF capacitor to ground; never leave AREF floating when the internal reference is selected.
Compliance Information
Listed as green QFN/MLF package (RoHS/lead-free) per DigiKey and Mouser. Automotive AEC-Q100 qualification applies to the ATMEGA48PB-AUR variant, not this part. REACH and conflict-minerals status should be confirmed via Microchip's Quality portal certificates.
