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DIP-8 · ATtiny85-20PU
Active8-bit AVR MCU
ATtiny85-20PU
Microchip Technology · DIP-8 · 8-bit AVR MCU
Price on Request
Get a competitive quote within 24 hours. Volume discounts available. Shenzhen stock ships in 1-2 business days.
Overview
The ATtiny85-20PU is the eight-pin workhorse of the AVR family: 8 KB of Flash, 512 bytes of SRAM, 512 bytes of EEPROM and six programmable I/O lines in a through-hole 8P3 PDIP that fits a breadboard without an adapter. Because the whole device runs from a single supply and boots off its internal calibrated 8 MHz oscillator (doubling to 16 MHz with the on-chip PLL), a working circuit can be as few as three parts. The -20 suffix is the 20 MHz speed grade, specified at 4.5 V to 5.5 V; at 2.7 V to 5.5 V the same die is guaranteed to 10 MHz. If you need 20 MHz headroom from a 3.3 V rail, buy the ATtiny85V-10PU instead and design around 10 MHz.
The peripheral mix is unusually rich for eight pins: a 4-channel 10-bit ADC with two differential pairs offering 1x or 20x programmable gain, an analog comparator, a universal serial interface that can be clocked as SPI, I2C-like two-wire or UART-style link, an 8-bit timer with two PWM channels, and a second high-speed 8-bit timer with its own PLL producing two PWM outputs plus a programmable dead-time generator. That dead-time generator is why ATtiny85 shows up in small BLDC and H-bridge drivers, LED dimmers and boost converters rather than just blinking an LED. debugWIRE gives single-wire debug and ISP over SPI keeps programming trivial with a USBasp or an Arduino-as-ISP.
Sourcing reality: Microchip lists the ATtiny85 as Active under its longevity programme, so authorised channel supply is stable, but the DIP-8 package carries a premium over the ATtiny85-20SU (SOIC) and ATtiny85-20MU (QFN). Counterfeit activity concentrates on two tricks: remarked ATtiny85V-10PU chips sold as -20PU (they die above 10 MHz at 5 V), and blank or lower-density ATtiny25/45 dies relabelled as 85. Both are easy to catch electrically - read the signature bytes with avrdude (1E 93 0B for a genuine ATtiny85) and read the flash size, which reports 8 KB only on a real 85. Shenzhen stock is deep for this part; MOQ is typically one tube of 10 pcs for DIP prototypes and 500 to 2,000 pcs for volume.
Key Features
- 8 KB Flash / 512 B SRAM / 512 B EEPROM with six programmable I/O in a DIP-8
- 20 MHz speed grade at 4.5-5.5 V; 10 MHz down to 2.7 V
- 4-channel 10-bit ADC with 1x and 20x programmable-gain differential pairs
- High-speed timer with on-chip PLL, two PWM outputs and dead-time generator
- debugWIRE plus ISP over SPI; runs from the internal 8 MHz calibrated oscillator
Typical Applications
- Compact sensor nodes, thermostats and small data loggers
- LED dimmers, fan controllers and low-power H-bridge or boost-converter drivers
- Wearable and battery gadgets that only need a few pins (Digispark-style boards)
- Replacement MCUs in legacy appliances and field-serviceable through-hole repairs
- Education, STEM kits and rapid breadboard prototyping
Specifications
- Core
- AVR 8-bit RISC
- Max Clock
- 20 MHz
- Flash
- 8 KB
- SRAM
- 512 bytes
- I/O Lines
- 6
- Supply Voltage
- 2.7 to 5.5 V
- ADC
- 4-channel, 10-bit
- Operating Temperature
- -40 to 85 °C
- Pins
- 8
- RoHS
- Compliant
Procurement Tips
Order ATtiny85-20PU for 5 V designs and ATtiny85V-10PU for 3.3 V or battery designs - they are the same package and pinout, so one PCB can serve both, and specifying the correct speed grade up front avoids a remarked-part surprise at 20 MHz.
Frequently Asked Questions
What is the difference between ATtiny85-20PU and ATtiny85V-10PU?
Same die, same pinout, same memory. The prefix V marks the low-voltage speed grade: ATtiny85V-10PU runs 0-4 MHz from 1.8 V and 0-10 MHz from 2.7 V, while ATtiny85-20PU runs 0-10 MHz from 2.7 V and 0-20 MHz from 4.5 V. Choose -20PU for 5 V designs needing full speed, V-10PU for battery designs at 3.3 V or lower.
How is the ATtiny85 different from the ATtiny84 or ATtiny861?
The ATtiny85 has six I/O in 8 pins; the ATtiny84 offers 12 I/O in a 14-pin package and the ATtiny861 adds a dedicated motor-control timer with more PWM outputs in 20 pins. If you are pin-constrained and need only a handful of I/O, the 85 is the cheapest; if you need more pins for the same flash size, step to the 84 or 85 to 861 without changing toolchain.
Can I use the internal oscillator instead of a crystal for timing-critical work?
The factory-calibrated 8 MHz RC is accurate to about 10 percent over voltage and temperature, which is fine for PWM, delays and bit-banged protocols but not for UART above roughly 9600 baud or any frequency measurement. You can re-calibrate it in firmware to about 1 percent at a fixed voltage and temperature, or use the external 16 MHz PLL clock for the high-speed timer.
Why does my ATtiny85 project work at 5 V but reset at 3.3 V?
Check two things. First, the default fuse settings keep the internal oscillator divided by 8, giving 1 MHz; at 3.3 V the brown-out detector (typically 2.7 V) may trip under load transients. Second, if you programmed it with the -20 grade expectation of 20 MHz, remember that speed grade requires 4.5 V minimum. Fix it by clearing CKDIV8, setting BODLEVEL appropriately and staying at or below 10 MHz on a 3.3 V rail.
How do I detect counterfeit ATtiny85-20PU chips?
Read the signature bytes and flash size with avrdude: a genuine ATtiny85 answers 1E 93 0B and reports 8 KB. Remarked ATtiny85V-10PU parts pass that test but fail above 10 MHz, so also run a soak test at 20 MHz and 5 V. Physically, Microchip parts have laser-etched marking, matte-tin leads and a consistent pin-1 dimple; ink-printed or shiny re-plated leads indicate a rework. We test signature, flash size and full-speed operation on samples from every lot.
What is the MOQ and lead time for ATtiny85-20PU?
Prototype MOQ is one factory tube (10 pcs DIP-8). Volume orders start at 500 pcs loose or 2,000 pcs in tape and reel for the SOIC variant. Authorised Microchip channel lead time is typically 8-16 weeks; our Shenzhen stock usually ships in 1-2 business days for quantities under 20,000 pcs.
Is the ATtiny85 still recommended for new designs, or should I move to tinyAVR 0-series?
The ATtiny85 is fully supported and will remain in production for years under Microchip longevity commitments, and the Arduino/micrOLED ecosystem around it is enormous. For new high-volume designs the tinyAVR 0-series (ATtiny816, ATtiny826, ATtiny841) offers more peripherals, better ADC and lower price, but the footprint and toolchain differ. Keep the ATtiny85 where its 8-pin footprint and DIP availability matter.
Alternatives & Equivalents
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