ATMEGA48P-20PU - 8-bit AVR MCU 4KB Flash 20MHz PDIP-28 | Microchip
MPN: ATMEGA48P-20PU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.38 | $1.38 |
| 10 | $1.31 | $13.10 |
| 100 | $1.21 | $121.00 |
| 500 | $1.13 | $565.00 |
| 1,000 | $1.05 | $1,050.00 |
ATMEGA48P-20PU Overview
A microcontroller (MCU) is a single integrated circuit that combines a processor core, program memory, data memory, and programmable peripherals on one chip. The 8-bit AVR family sits within Microchip's broader microcontroller portfolio and is widely used in embedded systems, education, and hobbyist electronics because of its simple architecture, free toolchains, and broad documentation.
Key features of the ATMEGA48P-20PU include an AVR enhanced RISC core executing most instructions in a single clock cycle (131 instructions, 32 general-purpose working registers), three flexible timer/counters with compare modes, an internal oscillator, a 10-bit 8-channel ADC, and a UART with bitrate generator plus USI for SPI/I2C-style communication. The picoPower technology provides six software-selectable power-saving modes, making it attractive for battery-powered designs.
Architecturally, the device uses Harvard memory separation between program and data buses, and in-system self-programmable Flash allows firmware updates over SPI using an ISP programmer. Operating voltage spans 1.8 V to 5.5 V, enabling both 3.3 V and 5 V designs at up to 20 MHz (with speed derating below 5 V).
Typical applications include industrial control, home automation sensors, small appliances, motor-adjacent control loops, and educational prototypes. The through-hole DIP-28 package is especially convenient for breadboarding and low-volume hand assembly.
Design consideration: choose the clock source carefully - the internal 8 MHz RC oscillator reduces BOM cost, while an external crystal improves UART timing accuracy.
This page synthesizes distributor pricing, drop-in alternatives across the ATmega48/88/168/328 family, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA48P-20PU — 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-20PU (same form factor and footprint) — differing in EEPROM, SRAM, Operating Temperature, Supply Voltage Range, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA48PA-PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →ATMEGA48A-PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.78 / Unit
View Datasheet →ATMEGA48-20PI
✅ Drop-In✓ In Stock
$0.98 / Unit
View Datasheet →ATMEGA88PA-PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.85 / Unit
View Datasheet →ATMEGA328P-PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
Contact for price
View Datasheet →ATMEGA168PA-PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.86 / Unit
View Datasheet →ATMEGA48P-20PU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Flash Memory | 4 KB (2K x 16) ISP |
| EEPROM | 256 B |
| SRAM | 512 B |
| Maximum Clock Frequency | 20 MHz |
| Operating Voltage Range | 1.8 V to 5.5 V |
| General Purpose I/O | 23 lines |
| Working Registers | 32 x 8-bit general purpose |
| Timers/Counters | 3 (two 8-bit, one 16-bit) |
| ADC Resolution | 10-bit, 8 channels |
| Communication Interfaces | USART, SPI (USI), I2C-compatible |
| Low Power Technology | picoPower, 6 power-saving modes |
| Package | 28-PDIP (0.300 inch, 7.62 mm) |
| Mounting Type | Through Hole |
| Operating Temperature | 0C to 70C |
| RoHS Status | Compliant |
| In-System Programmable | Yes (SPI ISP) |
ATMEGA48P-20PU Pin Configuration
| Pin 1 | PC6 (RESET) — Port C bit 6 / Active-low reset input |
| Pin 2 | PD0 (RXD) — Port D bit 0 / USART receive data |
| Pin 3 | PD1 (TXD) — Port D bit 1 / USART transmit data |
| Pin 4 | PD2 (INT0) — Port D bit 2 / External interrupt 0 |
| Pin 5 | PD3 (INT1) — Port D bit 3 / External interrupt 1 |
| Pin 6 | PD4 (T0/XCK) — Port D bit 4 / Timer 0 counter input, USART external clock |
| Pin 7 | VCC — Digital supply voltage (1.8 V to 5.5 V) |
| Pin 8 | GND — Ground |
| Pin 9 | PB6 (XTAL1/TOSC1) — Port B bit 6 / Crystal oscillator input or timer oscillator |
| Pin 10 | PB7 (XTAL2/TOSC2) — Port B bit 7 / Crystal oscillator output |
| Pin 11 | PD5 (T1/OC0B) — Port D bit 5 / Timer 1 counter input, Timer 0 output compare B |
| Pin 12 | PD6 (AIN0/OC0A) — Port D bit 6 / Analog comparator positive input, Timer 0 output compare A |
| Pin 13 | PD7 (AIN1) — Port D bit 7 / Analog comparator negative input |
| Pin 14 | PB0 (ICP1/CLKO) — Port B bit 0 / Timer 1 input capture, system clock output |
| Pin 15 | PB1 (OC1A) — Port B bit 1 / Timer 1 output compare A (PWM) |
| Pin 16 | PB2 (SS/OC1B) — Port B bit 2 / SPI slave select, Timer 1 output compare B (PWM) |
| Pin 17 | PB3 (MOSI/OC2A) — Port B bit 3 / SPI master output, Timer 2 output compare A (PWM) |
| Pin 18 | PB4 (MISO) — Port B bit 4 / SPI master input |
| Pin 19 | PB5 (SCK) — Port B bit 5 / SPI serial clock, ISP programming clock |
| Pin 20 | AVCC — ADC supply voltage |
| Pin 21 | AREF — ADC analog reference input |
| Pin 22 | GND — Ground |
| Pin 23 | PC0 (ADC0) — Port C bit 0 / ADC channel 0 |
| Pin 24 | PC1 (ADC1) — Port C bit 1 / ADC channel 1 |
| Pin 25 | PC2 (ADC2) — Port C bit 2 / ADC channel 2 |
| Pin 26 | PC3 (ADC3) — Port C bit 3 / ADC channel 3 |
| Pin 27 | PC4 (ADC4/SDA) — Port C bit 4 / ADC channel 4, I2C-compatible data line |
| Pin 28 | PC5 (ADC5/SCL) — Port C bit 5 / ADC channel 5, I2C-compatible clock line |
Typical Applications
ATMEGA48P-20PU is suitable for 6 applications: Industrial Control Systems, Battery-Powered Sensor Nodes, Home Automation and Smart Home, Consumer Appliances, Education and Prototyping, Automotive Auxiliary (Non-Safety) Electronics.
Industrial Control Systems
The ATMEGA48P-20PU fits low-end industrial control nodes such as relay sequencers, motor start-stop logic, and sensor polling units. Its 10-bit ADC with 8 channels reads analog transducers directly, while the three timer/counters (two 8-bit, one 16-bit) generate PWM for actuator drive with compare modes that offload timing from the CPU. Operating from 1.8 V to 5.5 V, it tolerates noisy industrial supply rails, and the industrial-grade ATMEGA48-20PI sibling extends the range to -40C to +85C when wider temperature coverage is required. The USART with bitrate generator links to supervisory PLCs over RS-485 via an external transceiver, and the 4 KB Flash is typically sufficient for state-machine based control code. Watchdog timer support adds fault recovery in unattended installations.
Recommended
Battery-Powered Sensor Nodes
The picoPower technology in the ATMEGA48P-20PU makes it a strong fit for battery-operated sensor nodes reporting temperature, humidity, or motion. In Power-down sleep mode the main oscillator stops and supply current falls to the low-microamp range, while the watchdog timer or asynchronous timer can wake the device on a schedule. A typical cycle - wake, sample the 10-bit ADC, transmit over USART or USI, then sleep for seconds or minutes - gives multi-year battery life from a pair of AA cells. The 1.8 V minimum supply allows direct operation from two alkaline cells through most of their discharge curve, avoiding a boost converter. The 256 B EEPROM retains calibration constants and counters across battery replacement without external non-volatile memory.
Recommended
Home Automation and Smart Home
For smart-home endpoints such as wall switches, IR remote repeaters, door sensors, and simple actuators, the ATMEGA48P-20PU offers an economical 8-bit platform with the right peripheral mix. The USI module implements SPI or I2C-compatible links to inexpensive peripherals (EEPROMs, RTCs, sensor ICs), while 23 GPIO lines switch relays and LEDs directly at up to 20 mA per pin. The 20 MHz maximum clock comfortably handles simple RF module bit-banging for 433 MHz protocols. Because the device is through-hole in DIP-28, it suits hand-assembled low-volume smart home products and rapid prototype iterations. The six power-saving modes keep idle consumption minimal for mains-brownout-tolerant designs with supercapacitor backup.
Recommended
Consumer Appliances
Small appliances - coffee makers, fans, water pumps, and lighting controls - commonly use a single 8-bit MCU for user-interface scanning, timer control, and load switching. The ATMEGA48P-20PU covers these needs with three timer/counters providing PWM for triac or motor drive, an ADC channel for potentiometer or thermistor input, and 23 GPIO for touch-style keys and indicator LEDs. Its 1.8 V to 5.5 V supply range and robust I/O simplify designs that sense mains presence through optocouplers. The 0C to 70C commercial temperature range matches typical indoor appliance environments, and the low unit price (around $1.38 in single quantity as of 2026-09-18) supports aggressive BOM targets in cost-sensitive consumer products.
Recommended
Education and Prototyping
The DIP-28 through-hole package makes the ATMEGA48P-20PU ideal for education and breadboard prototyping: it inserts into standard 0.3-inch DIP sockets, survives repeated removal, and can be programmed with low-cost USBasp or AVRISP mkII tools over the SPI ISP interface. Community toolchains such as MCUdude MiniCore add Arduino IDE support for the ATmega48, letting students move from blinky projects to timer, ADC, and UART exercises on a sub-$2 chip. The AVR architecture - 131 mostly single-cycle instructions and 32 working registers - is well documented in Microchip's academic materials. Skills transfer directly up the family: the same programmer and pinout apply to ATMEGA88PA, ATMEGA168PA, and ATMEGA328P-PU when projects need more Flash.
Recommended
Automotive Auxiliary (Non-Safety) Electronics
In 12 V automotive auxiliary circuits such as interior lighting dimmers, relay time-delay modules, and aftermarket accessory controllers, the ATMEGA48P-20PU serves as the control element behind a 5 V regulator. The ADC samples battery-voltage dividers and thermistors, timer PWM drives lamp dimming, and the EEPROM stores learned configuration across key-off power cycles. Designers must add load-dump protection (TVS diode and series regulator) because the MCU itself is rated only 1.8 V to 5.5 V and 0C to 70C - for temperature-critical or safety-relevant positions, select an AEC-Q100-qualified MCU instead. The picoPower sleep modes suit modules that must draw minimal quiescent current from the battery when the vehicle is parked.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48P-20PU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48PA-PU | ATMEGA48A-PU | ATMEGA48-20PI | ATMEGA88PA-PU | ATMEGA328P-PU |
|---|---|---|---|---|---|---|
| Package | 28-PDIP | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same | 28-PDIP - 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 | 32 KB |
| SRAM | 512 B | 512 B | 512 B | 512 B | 1 KB | 2 KB |
| EEPROM | 256 B | 256 B | 256 B | 256 B | 512 B | 1 KB |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| picoPower Technology | Yes | Yes (improved) | No | No | Yes | Yes |
| Operating Temperature | 0C to 70C | 0C to 70C | 0C to 70C | -40C to 85C (industrial) | 0C to 70C | 0C to 70C |
Key Differentiators
- picoPower low-sleep-current technology (vs ATMEGA48A-PU)
- Lowest-cost entry into the ATmega PDIP family (vs ATMEGA328P-PU)
- 20 MHz speed grade with wide 1.8-5.5 V supply (vs ATMEGA48-20PI)
Design Notes
Decouple VCC and AVCC independently: place a 100 nF ceramic capacitor directly across pins 7 (VCC) and 8 (GND), and a second 100 nF capacitor plus optional 10 uF bulk at pin 20 (AVCC) with pin 21 (AREF). AVCC must be connected to VCC even if the ADC is unused. Do not share a single long ground return for ADC and switching loads - the 10-bit ADC is sensitive to ground bounce from relay or LED drive currents on Port B and D.
Pin 1 (PC6/RESET) must not be configured as GPIO if you intend to reprogram the device over ISP, because the SPI programming interface requires a functional RESET. Similarly, avoid repurposing PB3/PB4/PB5 (MOSI/MISO/SCK) for high-noise external loads unless you add series resistors, since these lines double as the ISP programming bus. Estimated: with internal 8 MHz RC oscillator, UART timing error is typically a few percent - use an external crystal if reliable baud rates above 9600 at 3.3 V are needed.
The ATMEGA48P-20PU dissipates very little power at typical loads: estimated at 5 V and 20 mA total I/O sink/source plus ~6 mA core operation, dissipation is roughly 130 mW, far below the PDIP-28 thermal capability, so no heatsinking is required. The practical thermal constraint is per-pin I/O: keep sustained DC current at or below the datasheet per-pin limit (typically 40 mA absolute maximum per I/O) and observe total VCC/GND current limits for the package.
For in-system programming, route a 6-pin ISP header (MOSI PB3, MISO PB4, SCK PB5, RESET PC6, VCC, GND) to a board edge connector. Keep ISP traces short and add 10-100 ohm series resistors on MOSI/SCK if those pins also drive external circuitry, so the programmer can override it. On hand-soldered DIP-28 boards, use a socket to allow firmware-locked or damaged chips to be swapped without desoldering.
Compliance Information
RoHS compliant and lead-free per Microchip product listing (Mouser lists the part as TEMP GRN - green/lead-free packaging). REACH and conflict-minerals status not stated in the provided data.
