ATMEGA48PA-MMHR - 4KB Flash 20MHz AVR MCU | Microchip
MPN: ATMEGA48PA-MMHR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.63 | $2.63 |
| 10 | $2.4 | $24.00 |
| 100 | $2.1 | $210.00 |
| 500 | $1.85 | $925.00 |
| 1,000 | $1.62 | $1,620.00 |
ATMEGA48PA-MMHR Overview
An AVR ATmega microcontroller is a member of the 8-bit AVR RISC family - a Harvard-architecture embedded processor that combines program FLASH, data SRAM, EEPROM, timers, and communication peripherals on a single chip within the broader hierarchy of microcontroller units (MCUs) for embedded systems.
Key features include 131 powerful instructions with most executing in a single clock cycle, 32 general-purpose working registers, and throughput of up to 20 MIPS at 20 MHz. The picoPower technology delivers very low power consumption in sleep modes, while the operating voltage spans 1.8V to 5.5V, supporting both battery-powered and 5V industrial designs. Peripherals include one 8-bit and one 16-bit timer/counter with compare modes, a 10-bit ADC, a programmable serial USART, a byte-oriented 2-wire serial interface (I2C compatible), an SPI serial port, a programmable watchdog timer with separate on-chip oscillator, and an on-chip analog comparator.
Technical depth: the advanced RISC architecture provides power-on reset and programmable brown-out detection, plus an internal calibrated oscillator that removes the need for an external crystal in many designs. Interrupt and wake-up on pin change support low-power event-driven operation.
Typical applications include battery-powered sensor nodes, industrial control and HVAC systems, consumer appliances, and low-cost human-interface devices where the compact 4x4 mm footprint suits dense PCB layouts.
Design consideration: if migrating to the newer ATMEGA48PB, verify the two documented pin-functionality cautions on pins 3 and 6 before assuming drop-in compatibility.
This page synthesizes distributor pricing, verified drop-in alternatives, pinout data, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for ATMEGA48PA-MMHR 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 ATMEGA48PA-MMHR (same form factor and footprint) β differing in Flash Memory, Package, EEPROM, SRAM, Communication Interfaces.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA48PB-MMHR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA88PA-MMHR
β Drop-Inβ In Stock
$2.05 / Unit
View Datasheet βATMEGA168PA-MMHR
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA48A-MMH
β Drop-Inβ In Stock
$0.86 / Unit
View Datasheet βATMEGA48-20MMH
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA48PA-MMHR Maximum Ratings & Electrical Characteristics
| Core | AVR 8-bit RISC |
| Flash Memory | 4 KB (2K x 16) |
| EEPROM | 256 B |
| SRAM | 512 B |
| Maximum Clock Frequency | 20 MHz |
| Maximum Throughput | 20 MIPS at 20 MHz |
| Operating Voltage Range | 1.8 V to 5.5 V |
| I/O Lines | 23 |
| ADC Resolution | 10-bit |
| Timers | 1 x 8-bit, 1 x 16-bit (plus RTC timer) |
| Communication Interfaces | USART, SPI, 2-wire (I2C compatible) |
| Analog Comparator | Yes, 1 on-chip |
| Watchdog Timer | Programmable, separate on-chip oscillator |
| Operating Temperature | -40C to +85C (IND) |
| Package | 28-pad VQFN/MLF, 4x4 mm, 0.45 mm pitch, 1 mm height |
| Mounting Type | Surface Mount |
| Packing | Tape & Reel (R suffix) |
| RoHS Status | Green / RoHS compliant package |
ATMEGA48PA-MMHR Pin Configuration
| Pin 1 | PC6 / RESET β Port C bit 6 or active-low external reset input |
| Pin 2 | PD0 / RXD β Port D bit 0, USART receive |
| Pin 3 | PD1 / TXD β Port D bit 1, USART transmit |
| Pin 4 | PD2 / INT0 β Port D bit 2, external interrupt 0 |
| Pin 5 | PD3 / INT1 / OC2B β Port D bit 3, external interrupt 1 or Timer2 compare output |
| Pin 6 | PD4 / T0 / XCK β Port D bit 4, Timer0 clock input or USART external clock |
| Pin 7 | VCC β Digital supply voltage |
| Pin 8 | GND β Ground |
| Pin 9 | PB6 / XTAL1 / TOSC1 β Port B bit 6, crystal oscillator input or RTC oscillator input |
| Pin 10 | PB7 / XTAL2 / TOSC2 β Port B bit 7, crystal oscillator output or RTC oscillator output |
| Pin 11 | PD5 / OC0B / T1 β Port D bit 5, Timer0 compare output or Timer1 clock input |
| Pin 12 | PD6 / OC0A / AIN0 β Port D bit 6, Timer0 compare output or analog comparator positive input |
| Pin 13 | PD7 / AIN1 β Port D bit 7, analog comparator negative input |
| Pin 14 | PB0 / ICP1 / CLK0 β Port B bit 0, Timer1 input capture or divided system clock output |
| Pin 15 | PB1 / OC1A β Port B bit 1, Timer1 compare output A |
| Pin 16 | PB2 / SS / OC1B β Port B bit 2, SPI slave select or Timer1 compare output B |
| Pin 17 | PB3 / MOSI / OC2A β Port B bit 3, SPI master output or Timer2 compare output A |
| Pin 18 | PB4 / MISO β Port B bit 4, SPI master input |
| Pin 19 | PB5 / SCK β Port B bit 5, SPI serial clock |
| Pin 20 | AVCC β ADC and analog supply voltage |
| Pin 21 | AREF β ADC analog reference voltage |
| Pin 22 | GND β Ground (analog ground return in 28-pad package) |
| Pin 23 | PC0 / ADC0 β Port C bit 0, ADC channel 0 |
| Pin 24 | PC1 / ADC1 β Port C bit 1, ADC channel 1 |
| Pin 25 | PC2 / ADC2 β Port C bit 2, ADC channel 2 |
| Pin 26 | PC3 / ADC3 β Port C bit 3, ADC channel 3 |
| Pin 27 | PC4 / ADC4 / SDA β Port C bit 4, ADC channel 4 or 2-wire data line |
| Pin 28 | PC5 / ADC5 / SCL β Port C bit 5, ADC channel 5 or 2-wire clock line |
Typical Applications
ATMEGA48PA-MMHR is suitable for 6 applications: Battery-Powered Sensor Nodes, Industrial Control and Automation, Consumer Appliances and White Goods, Human Interface Devices and Controllers, HVAC and Building Automation, Low-Cost IoT Edge Nodes.
Battery-Powered Sensor Nodes
The ATMEGA48PA-MMHR fits battery-powered sensor nodes because its picoPower technology minimizes sleep-mode current, which dominates energy budgets in duty-cycled wireless and wired sensor products. With the 1.8V operating floor, the MCU runs directly from two alkaline cells without a boost converter, saving BOM cost and quiescent losses. In typical use, the node sleeps with the watchdog timer or pin-change interrupt as wake source, samples its 10-bit ADC every few seconds, and transmits readings over USART or SPI. The 512B SRAM handles several sensor samples and protocol frames, while 4KB FLASH stores the firmware and a small bootloader. Performance consideration: budget wake-up and ADC conversion time against sleep time to hit target battery life.
Recommended
Industrial Control and Automation
In industrial control, the ATMEGA48PA-MMHR provides robust 8-bit control over -40C to +85C, meeting the industrial temperature requirement stated in the device specifications. The programmable brown-out detector and power-on reset ensure deterministic startup on noisy factory floors, while the watchdog timer with its separate on-chip oscillator recovers the system from firmware lockups. The 23 I/O lines drive relays, read limit switches, and communicate over the USART or SPI to industrial modules. Because the core runs at 20 MIPS, single-cycle interrupt latency supports deterministic pulse counting for encoders and flow meters. Performance consideration: at 5V operation, verify the maximum clock allowed by the voltage-frequency curve before fixing the system crystal frequency.
Recommended
Consumer Appliances and White Goods
Consumer appliances benefit from the ATMEGA48PA-MMHR's low cost, GREEN RoHS package, and integrated analog peripherals. A single device can scan a button matrix on port pins, multiplex an LED or segment display via timers, measure an NTC thermistor with the 10-bit ADC, and manage a triac or relay drive from a timer compare output. The internal calibrated oscillator eliminates the external crystal in applications where 8 MHz-class accuracy suffices, freeing two I/O pins and lowering BOM cost. The 4x4 mm 0.45 mm-pitch VQFN footprint fits tight PCB areas behind appliance control panels. Performance consideration: ensure ADC reference stability (AVCC/AREF decoupling) for repeatable temperature readings across the product's operating envelope.
Recommended
Human Interface Devices and Controllers
For keyboards, rotary encoders, remote controls, and simple HID controllers, the ATMEGA48PA-MMHR offers fast single-cycle I/O toggling, pin-change interrupts on all ports, and enough FLASH for scan loops, debounce logic, and communication protocols. The 23 GPIO lines support large key matrices; the 2-wire interface connects to I2C expanders or EEPROMs, and the USART links to serial Bridges. The internal 8 MHz oscillator is sufficient for scanning applications, reducing component count. Sleep modes allow battery-powered remotes to last years between cell changes, waking on pin-change interrupts from key presses. Performance consideration: implement row/column scanning with short settle times so that the 10-bit ADC or comparator used for capacitive sensing is not disturbed by scan transients.
Recommended
HVAC and Building Automation
HVAC controllers use the ATMEGA48PA-MMHR to read temperature, humidity, and pressure sensors via its 10-bit ADC, compute PID control in firmware, and drive fans, valves, and dampers through timer PWM outputs. Operation to 1.8V allows battery-backed thermostat operation, while the 5.5V ceiling supports directly powered 5V logic boards. The 2-wire interface connects to I2C environmental sensors and EEPROM parameter storage, and the USART links to RS-485 transceivers for building networks. Brown-out detection prevents corrupted EEPROM writes during brown-out events, protecting calibration data. Performance consideration: size the PWM frequency against actuator behavior, and use the 16-bit timer for accurate timebase generation in scheduling functions.
Recommended
Low-Cost IoT Edge Nodes
The ATMEGA48PA-MMHR serves as a low-cost IoT edge controller managing a radio module (via USART or SPI) and one or two analog sensors. Its 4KB FLASH accommodates a minimal application plus a serial protocol driver, while picoPower sleep between reporting intervals keeps average current in the microamp range. The 2-wire interface reads I2C sensors; the 10-bit ADC handles voltage and battery monitoring. Because the part is pin-compatible with ATMEGA88PA and ATMEGA168PA in the same 28-pad VQFN, firmware growth (TLS-lite stacks, richer protocols) can be absorbed by swapping to a bigger sibling without PCB respin - a valuable risk hedge for long-lived IoT products. Performance consideration: carefully partition FLASH between application and OTA bootloader, since 4KB leaves limited space.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48PA-MMHR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48PB-MMHR | ATMEGA88PA-MMHR | ATMEGA168PA-MMHR | ATMEGA48A-MMH |
|---|---|---|---|---|---|
| Package | 28-pad VQFN (MLF) 4x4 mm | 28-pad VQFN (MLF) 4x4 mm - same | 28-pad VQFN (MLF) 4x4 mm - same | 28-pad VQFN (MLF) 4x4 mm - same | 28-pad VQFN (MLF) 4x4 mm - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 4 KB | 4 KB | 8 KB | 16 KB | 4 KB |
| SRAM | 512 B | 512 B | 1 KB | 1 KB | 512 B |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| picoPower (Low-Power Sleep) | Yes (PA grade) | Yes (PB grade, improved) | Yes (PA grade) | Yes (PA grade) | No (A grade) |
| Drop-in Compatibility Notes | Reference device | Drop-in with pin 3 / pin 6 driving cautions | Full pin-to-pin drop-in | Full pin-to-pin drop-in | Pin-to-pin, electrical differences in sleep current |
Key Differentiators
- Lowest cost entry point of the picoPower megaAVR family (vs ATMEGA88PA-MMHR)
- picoPower low-power sleep modes at 4KB density (vs ATMEGA48A-MMH)
- Guaranteed same-footprint upgrade path (vs ATMEGA168PA-MMHR)
Design Notes
Connect AVCC (pin 20) to VCC through a low-pass filter (typically an LC or RC network) and decouple with 100 nF to GND; the ADC accuracy specification is only valid when AVCC does not differ from VCC by more than 0.3V. Decouple VCC (pin 7) with 100 nF ceramic close to the pad. If using the ADC internal 1.1V reference, add 100 nF on AREF (pin 21) but never connect AREF directly to a voltage source when the internal reference is enabled.
When migrating from ATMEGA48PA-MMHR to the newer ATMEGA48PB-MMHR, Microchip documentation requires two cautions for drop-in use: pin 3 must not be actively driven if it is connected to GND and the analog comparator output (ACO) must not be enabled, and pin 6 must not be actively driven if it is connected to VCC. Failing to verify these conditions can cause excessive current draw or malfunction on an otherwise identical footprint.
The 28-pad VQFN (MLF) 4x4 mm package has a central exposed pad that should be soldered to a grounded PCB thermal pad with an array of vias for mechanical strength and thermal relief - the MLF pad is the primary ground connection for the die. Use 0.45 mm pitch footprints per IPC-compliant Microchip layout files; verify stencil aperture design so the perimeter pins and the exposed pad reflow correctly during lead-free assembly.
For in-system programming and debugging, reserve access to MOSI (pin 17), MISO (pin 18), SCK (pin 19), and RESET (pin 1) via a 2x3 ICSP header; MPLAB SNAP or Atmel-ICE uses these pins plus power. Avoid loading RESET with heavy capacitance beyond the recommended 100 nF, and add an external 10k pull-up on RESET in electrically noisy environments to prevent spurious resets.
Compliance Information
Package described as GREEN per device specifications, indicating RoHS-compliant, halogen-free, lead-free construction. REACH and conflict-minerals status must be confirmed via Microchip's environmental portal.
