AT89C52-20PI Microchip Integrated Circuit (Dual-In-Line Packages) In Stock
AT89C52-20PI is an 8-bit 8051-compatible microcontroller in a 40-pin DIP package running up to 20 MHz with 8 KB of internal Flash, 256 bytes of RAM, and three 16-bit timers. It features a full-duplex UART, 32 I/O pins, and ISP programming capability. Available from stock worldwide at competitive pricing.
- Manufacturer
- Microchip
- Package
- Dual-In-Line Packages
- Pin Count
- 40
- Lifecycle
- ACTIVE
- Datasheet
- AT89C52-20PI Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $37.7740(MOQ 1)
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of AT89C52-20PI?
- 8 KB internal Flash with ISP (In-System Programming) support allows field firmware updates without removing the 40-pin DIP device from the target board
- Up to 20 MHz operation with three 16-bit timers enables precise time-base generation and multi-event timing in 8051-compatible designs
- 32 general-purpose I/O pins organized in 4 independent 8-bit ports provide ample GPIO for parallel sensor and display interfacing
- Full-duplex on-chip UART supports serial communication with modems, GPS modules, and PC host interfaces at programmable baud rates
What is AT89C52-20PI used for?
AT89C52-20PI is widely deployed in legacy and cost-sensitive embedded control applications that leverage the well-established 8051 instruction set, including industrial relay controllers, vending machine logic boards, and educational microcontroller trainer kits. Its 8 KB Flash and 20 MHz maximum clock are sufficient for menu-driven LCD interfaces, keypad scanning, and simple PID control loops found in home appliance and HVAC equipment. The 40-pin DIP package makes it a preferred choice for breadboard prototyping and socketed designs where the microcontroller may need field replacement.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Where can I find the AT89C52-20PI datasheet?
AT89C52-20PI Datasheet DownloadOfficial datasheet from Microchip
What are equivalent replacements for AT89C52-20PI?
Compatible alternatives and drop-in replacements for AT89C52-20PI:
suggested
suggested
suggested
suggested
suggested
suggested
suggested
Frequently Asked Questions
What is the maximum clock speed of AT89C52-20PI and how many timers does it include for time-critical embedded tasks?
AT89C52-20PI operates at a maximum clock frequency of 20 MHz and integrates three independent 16-bit timer/counter modules. Each timer can generate periodic interrupts, measure external pulse widths, or drive a baud rate generator for the on-chip UART. At 20 MHz with a standard 12-clock machine cycle, the device executes approximately 1.67 million instructions per second, which is sufficient for real-time control tasks such as relay sequencing and keypad debounce.
How does AT89C52-20PI's on-chip Flash support firmware updates compared to older mask-ROM 8051 variants?
AT89C52-20PI stores its program in 8 KB of internal Flash, which can be erased and reprogrammed electrically via the ISP interface without removing the chip from the circuit. Older mask-ROM 8051 devices required factory programming and could not be updated in the field, making any firmware bug or feature change very costly. The Flash architecture of AT89C52-20PI enables at least 1000 erase/write cycles, allowing iterative firmware development and post-production field updates with a standard ISP programmer.
For a new design, when is AT89C52-20PI a better choice than migrating to a PIC or ARM Cortex-M microcontroller?
AT89C52-20PI is the better choice when a design must maintain 8051 source-code compatibility with an existing firmware base of thousands of lines, because porting 8051 assembly or C to a different architecture incurs significant re-verification cost. It is also preferred when a customer requires a DIP-40 socketed replacement for field maintenance, or when the application runs from a simple 5 V single-supply and the 8 KB Flash and 256 bytes of RAM are adequate. For these legacy-sustaining scenarios, the lower unit cost of an 8051-class device versus an ARM Cortex-M also favors AT89C52-20PI.
How many I/O pins does AT89C52-20PI provide and how can they be organized for a mixed parallel and serial interface design?
AT89C52-20PI provides 32 general-purpose I/O pins arranged as 4 independent 8-bit ports (P0 through P3). In a mixed-interface design, P0 can serve as an 8-bit multiplexed address/data bus to an external LCD module, P2 as the upper address byte for external memory expansion, P3 carries the dedicated UART TX/RX lines and external interrupt inputs, and P1 remains fully available for GPIO such as keypad rows and columns. This flexible port assignment allows the 32 I/O pins to support parallel and serial peripherals simultaneously on a single chip.
Related Guides
CDSOT23-SM712 RS-485 Interface Protection Design Guide
Design robust RS-485 protection with CDSOT23-SM712 using correct clamping, placement, grounding, termination, and surge coordination.
Jul 17, 2026
CR0805-FX-10R0ELF 10 Ohm 0805 Resistor Design Guide
Design CR0805-FX-10R0ELF into 0805 circuits with practical power, pulse, thermal, layout, tolerance, and sourcing checks.
Jul 17, 2026
How to Choose Würth Elektronik 150141-Series SMD Indicator LEDs
Choose 150141RS73100 and related Würth 150141 LEDs by color, brightness, 3528 package fit, drive margin, and procurement controls.
Jul 15, 2026
Molex 53398-0371 Selection Guide: Choosing a 3-Circuit Wire-to-Board Header
Choose Molex 53398-0371 by circuit count, mating system, derating, PCB geometry, assembly needs, and exact-suffix sourcing.
Jul 15, 2026
Why Buy from FindMyChip
About Microchip
Microchip is a leading electronic component manufacturer. FindMyChip sources Microchip ICs directly from authorized China distributors, offering competitive pricing and reliable stock.
More from Microchip
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1+ | $44.4400 | $44.44 |
| 13+ | $39.9960 | $519.95 |
| 26+ | $37.7740 | $982.12 |
In Stock · 24h Response · Worldwide Shipping
Response within 24 hours · Worldwide shipping
“FindMyChip sourced our entire STM32 BOM in 48 hours when our usual distributor had 16-week lead times.”
You May Also Like
ACS770ECB-200U-PFF-T
Allegro Microsystems
Integrated Circuit
ACS770KCB-150U-PFF-T
Allegro Microsystems
Integrated Circuit
MC33901WEF
NXP
Integrated Circuit
MC7808BDTRKG
ON Semiconductor
Integrated Circuit
PA94EC
Apex Microtechnology
Integrated Circuit
AP7315-28SR-7
Diodes Inc.
Integrated Circuit
74HCT245D
Nexperia
Integrated Circuit
CY62256VNLL-70ZXCT
Cypress Semiconductor
Integrated Circuit
EPM7032AETC44-4N
Intel
Integrated Circuit
EPM3512AQC208-10N
Intel
Integrated Circuit
EPM3256ATC144-7N
Intel
Integrated Circuit
EPM3256AQC208-7N
Intel
Integrated Circuit
EPM3256AQC208-10N
Intel
Integrated Circuit
EPM3128ATC100-7N
Intel
Integrated Circuit
EPM1270F256C4N
Intel
Integrated Circuit
EPF8282ATC100-4N
Intel
Integrated Circuit
EPF6016QC208-2N
Intel
Integrated Circuit
EPF6016ATC144-3N
Intel
Integrated Circuit
EPF10K30ATC144-3N
Intel
Integrated Circuit
EPC2TI32N
Intel
Integrated Circuit
EPC2LC20
Intel
Integrated Circuit
EP3SL150F1152C4N
Intel
Integrated Circuit
EP2SGX60DF780C5N
Intel
Integrated Circuit
EP2SGX60CF780C5N
Intel
Integrated Circuit