SST39F040-55-4I-WHE Microchip Integrated Circuit (Small Outline Packages) In Stock
The SST39F040-55-4I-WHE is a 4 Mbit multi-purpose parallel NOR Flash memory from Microchip with a 55 ns access time, industrial temperature range, and a small-outline package. It supports byte-wide reads and sector erase for embedded code and data storage. Available from stock with worldwide shipping.
- Manufacturer
- Microchip
- Package
- Small Outline Packages
- Pin Count
- 32
- Lifecycle
- ACTIVE
- Datasheet
- SST39F040-55-4I-WHE Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SST39F040-55-4I-WHE?
- 4 Mbit NOR Flash with 55 ns maximum access time enables fast random-read code execution suitable for memory-mapped microprocessor designs
- Industrial temperature grade (-40 °C to +85 °C) ensures reliable operation in harsh environments such as automotive and factory automation equipment
- Sector erase architecture allows in-system firmware updates by erasing and reprogramming 4 kB sectors without erasing the entire array
What is SST39F040-55-4I-WHE used for?
The SST39F040-55-4I-WHE serves as code and data storage in embedded systems where a microprocessor or microcontroller executes firmware directly from NOR Flash in memory-mapped mode. Its 55 ns access time supports bus speeds up to 18 MHz without wait states, making it well suited for legacy 8-bit and 16-bit CPU designs in industrial controllers, BIOS storage, and communication equipment. The industrial temperature rating extends its usability to automotive body electronics, ruggedized instruments, and outdoor IoT gateways.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Where can I find the SST39F040-55-4I-WHE datasheet?
SST39F040-55-4I-WHE Datasheet DownloadOfficial datasheet from Microchip
What are equivalent replacements for SST39F040-55-4I-WHE?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How does the 55 ns access time of SST39F040-55-4I-WHE constrain the maximum bus clock frequency for a memory-mapped CPU?
With a 55 ns maximum read cycle time, the SST39F040-55-4I-WHE can support a CPU bus running at up to approximately 18 MHz (55 ns ≈ one full cycle at 18 MHz) with zero wait states. Faster processors clocked above 18 MHz must insert at least 1 wait state to satisfy the 55 ns timing requirement, which is a standard trade-off in 8-bit and 16-bit embedded designs using legacy parallel NOR Flash.
For an industrial controller that requires in-field firmware updates, how does the sector erase capability of SST39F040-55-4I-WHE help minimize downtime?
The SST39F040-55-4I-WHE supports sector erase in 4 kB blocks, allowing the bootloader to overwrite only the application firmware sectors—typically 512 kB of the 512 kB total array—without touching the bootloader sector itself. This reduces erase-and-reprogram cycles to the minimum necessary, cutting downtime during field updates to under 10 seconds for a full 4 Mbit image write at typical Flash programming speeds.
In what temperature range does SST39F040-55-4I-WHE operate and which industrial application classes does this cover?
The SST39F040-55-4I-WHE is specified for the industrial temperature range of -40 °C to +85 °C, covering IEC 60068-2 Class B environmental conditions. This makes it compliant for outdoor industrial enclosures, HVAC controllers, factory PLC modules, automotive non-powertrain electronics, and military-grade ground support equipment where ambient temperatures routinely reach temperature extremes well beyond the 0 °C to 70 °C commercial range.
Related Guides
CSD87313DMS Synchronous Buck Power Stage Design Guide
Design a compact CSD87313DMS synchronous buck stage with practical guidance for loss, gate drive, PCB layout, EMI, thermal validation, and sourcing.
Aug 6, 2026
STEF05SGR eFuse Selection Guide for 5 V Overcurrent Protection
Choose STEF05SGR for 5 V overcurrent protection by checking current-limit margin, inrush, thermal loss, fault response, and sourcing.
Aug 6, 2026
C0402C103K3RACTU Selection Guide: Choosing a 10 nF 0402 MLCC
Select C0402C103K3RACTU by voltage margin, X7R behavior, tolerance, 0402 assembly risk, and qualified alternatives.
Aug 4, 2026
STM32H753VIT6 MCU Selection Guide: Memory, Package, Connectivity, and Security
Choose STM32H753VIT6 by evaluating memory architecture, LQFP-100 pin fit, connectivity, security, power, and sourcing tradeoffs.
Aug 4, 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
In Stock · 24h Response · Worldwide Shipping
Response within 24 hours · Worldwide shipping
“Their engineering team helped us find a pin-compatible alternative when our original MCU went EOL.”
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