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Microchip Technology SST39LF020-55-4I-WHE
- Part No.:
- SST39LF020-55-4I-WHE
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 32-TFSOP (0.488", 12.40mm Width)
- Datasheet:
-
SST39LF020-55-4I-WHE.pdf
- Description:
- IC FLASH 2MBIT PARALLEL 32TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,103
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Product details
Overview
SST39LF020-55-4I-WHE from Microchip Technology (formerly Silicon Storage Technology) is a 2 Mbit (256K × 8) CMOS Multi-Purpose Flash memory IC with single 3.0–3.6V supply operation, 55 ns read access time, and JEDEC-standard x8 parallel interface. It features uniform 4 KB sector erase, 100,000 write/erase endurance, and >100 years data retention - deployed in embedded firmware storage for industrial controllers and legacy BIOS modules.
For engineers reviewing the SST39LF020-55-4I-WHE datasheet, SST39LF020-55-4I-WHE pinout, SST39LF020-55-4I-WHE application, or SST39LF020-55-4I-WHE equivalent, key selection criteria include its 32-pin PLCC package, hardware/software data protection, SuperFlash® technology's fixed program/erase timing, and compatibility with standard 8-bit microprocessor buses requiring nonvolatile code storage.
Technical Context
The SST39LF020-55-4I-WHE implements a split-gate SuperFlash cell architecture with thick-oxide tunneling injector, enabling consistent 14 µs byte-program and 18 ms sector-erase times independent of cycle count. Its control logic accepts JEDEC-standard command sequences via CE#, OE#, and WE# to initiate read, byte-program, sector-erase, chip-erase, and software ID operations.
It supports latched address/data bus operation, tri-state I/O outputs controlled by CE# and OE#, and end-of-write detection via Data# Polling (DQ7) and Toggle Bit (DQ6). The device operates across –40°C to +85°C (Industrial grade) and meets RoHS compliance in both 32-lead PLCC and TSOP packages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 2 Mbit (256K × 8), directly replaces 27C020 EPROM in socket-compatible designs |
| Read Access Time | 55 ns - enables direct interfacing with 14 MHz microcontrollers without wait states |
| Supply Voltage | 3.0–3.6 V - requires stable single-supply rail; no VPP pump needed |
| Endurance | 100,000 program/erase cycles - sufficient for field firmware updates over 10+ years |
| Data Retention | >100 years at 85°C - validated per JEDEC A103, suitable for unattended systems |
| Operating Temp | –40°C to +85°C (Industrial grade) - qualified for factory automation and telecom equipment |
| Package | 32-lead PLCC (WHE suffix) - surface-mount compatible with standard reflow profiles (260°C/10s) |
Pinout & Package
32-lead Plastic Leaded Chip Carrier (PLCC) package with J-lead configuration, RoHS-compliant, body size 11.43 mm × 11.43 mm × 3.56 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A16 | Address Inputs | A0–A16 select 256K-byte address space; A16 is MSB for SST39LF020 |
| DQ0–DQ7 | Data Input/Output | Bi-directional 8-bit data bus; tri-stated when CE# or OE# high |
| CE# | Chip Enable | Active-low device selection; disables outputs and reduces current to 1 µA in standby |
| OE# | Output Enable | Active-low output gating; allows data read without deselecting chip |
| WE# | Write Enable | Controls latching of address/data during program/erase; initiates internal timing sequences |
| VDD | Power Supply | 3.0–3.6 V supply; internal charge pump generates programming voltage |
| VSS | Ground | Reference return path for all signals and power |
| NC | No Connection | Pins 12, 17, 20, 31 - unconnected; must be left floating or tied to ground per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| SuperFlash® Technology | Fixed 14 µs byte-program and 18 ms sector-erase times - eliminates software de-rating over lifetime |
| Software Data Protection | Three-byte unlock sequence required before programming; six-byte sequence for erase - prevents accidental writes during power transitions |
| Hardware Write Inhibit | Automatic lockout when VDD < 1.5 V or WE#/CE#/OE# glitch < 5 ns - ensures robustness in noisy environments |
| JEDEC x8 Pinout Compliance | Direct drop-in replacement for 27C020, 29F020, and AM29F020 in existing 32-pin PLCC footprints |
| End-of-Write Detection | DQ6 toggle bit and DQ7 data polling - enables efficient polling-based firmware update routines without timers |
Applications
| Industrial PLC Firmware Storage | Legacy PC BIOS Memory |
|---|---|
Use Scenario: Storing ladder logic and configuration parameters in programmable logic controllers deployed in factory-floor environments with wide temperature swings and EMI exposure. IC Role / Device Role / Timing Role: Nonvolatile code and parameter storage accessed via 8-bit parallel bus; 55 ns read time supports real-time scan cycle execution. Use Value: 100,000-cycle endurance and >100-year retention ensure firmware integrity over full product lifecycle without field recalibration. | Use Scenario: Holding BIOS boot code and hardware initialization routines in desktop motherboards and embedded x86 systems from late 1990s–early 2000s. IC Role / Device Role / Timing Role: Primary boot ROM mapped to CPU address space; JEDEC-compliant pinout enables direct socket replacement of obsolete EPROMs. Use Value: Single 3.3V supply eliminates need for external VPP programming voltage, simplifying board power design and reducing BOM cost. |
| Telecom Line Card Configuration | Medical Device Calibration Data |
Use Scenario: Storing DSP firmware and port-specific configuration tables on carrier-grade DSLAM and optical line cards operating continuously at elevated ambient temperatures. IC Role / Device Role / Timing Role: Field-upgradable firmware storage with sector-erase granularity - allows patching individual functional blocks without full reflash. Use Value: Industrial temperature rating (–40°C to +85°C) and 256K × 8 density provide reliable operation in sealed, fanless enclosures. | Use Scenario: Retaining calibration coefficients, sensor offset values, and regulatory audit logs in Class II medical instruments requiring long-term traceability and data integrity. IC Role / Device Role / Timing Role: Secure, tamper-resistant nonvolatile memory with hardware/software write protection - prevents unauthorized modification of critical calibration data. Use Value: >100-year data retention and 100,000-cycle endurance meet FDA 21 CFR Part 11 and IEC 62304 requirements for life-critical storage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AM29F020B-55JF | 55 ns access, 3.0–3.6 V, but uses older floating-gate technology; 10,000-cycle endurance (vs. 100,000) | Lacks SuperFlash fixed-timing guarantee; slower erase (500 ms chip-erase vs. 70 ms) | Select only if legacy qualification mandates AMD footprint; verify endurance budget for frequent field updates |
| SST39VF020-70-4C-WHE | Wider 2.7–3.6 V supply range, 70 ns access, same 256K × 8 density and PLCC package | Lower voltage support enables battery-backed operation; 70 ns timing requires wait-state insertion on fast buses | Prefer for portable or low-power systems; avoid where 55 ns timing is mandatory for cycle-accurate timing |
Compared with AM29F020B-55JF, SST39LF020-55-4I-WHE delivers 10× higher endurance and 7× faster chip-erase, while SST39VF020-70-4C-WHE trades 15 ns read latency for 0.3 V lower minimum supply - making SST39LF020-55-4I-WHE optimal for industrial firmware where speed and longevity are prioritized over ultra-low-voltage operation.
Availability
SST39LF020-55-4I-WHE is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy BIOS replacement, telecom line card configuration, and medical device calibration data retention requiring stable component supply and long-lifecycle support.
Supply support for SST39LF020-55-4I-WHE includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology acquired Silicon Storage Technology (SST) in 2010 and continues to manufacture and support the SuperFlash family of parallel NOR flash devices.
The SST39LFxx series was designed specifically for cost-sensitive, high-reliability embedded applications requiring socket-compatible replacements for obsolete EPROMs and early flash devices - emphasizing endurance, data retention, and JEDEC interoperability.
FAQ
What is the maximum operating frequency supported by SST39LF020-55-4I-WHE?
The SST39LF020-55-4I-WHE does not specify a maximum clock frequency because it is an asynchronous parallel flash device. Its timing is governed by access times: 55 ns read cycle time (TRC) and 40 ns minimum WE#/CE# pulse width. System bus timing must comply with Table 12 and Table 13 in the DS25023B datasheet. For reliable operation with a 14 MHz microcontroller, no wait states are required due to the 55 ns access specification of the SST39LF020-55-4I-WHE.
Does SST39LF020-55-4I-WHE require an external VPP voltage for programming?
No, the SST39LF020-55-4I-WHE integrates an internal charge pump that generates the high voltage required for programming and erasing. It operates from a single 3.0–3.6 V supply - no external VPP pin or circuitry is needed. This simplifies PCB design and eliminates risks associated with external high-voltage generation. All write operations for the SST39LF020-55-4I-WHE are executed using standard microprocessor bus cycles with JEDEC-compliant command sequences.
How is software data protection enabled on SST39LF020-55-4I-WHE?
Software Data Protection (SDP) is permanently enabled at shipment. To program or erase, the host must first issue a three-byte unlock sequence (5555H/AAH → 2AAAH/55H → 5555H/A0H) for byte-program, or a six-byte sequence for sector/chip-erase. Invalid commands abort the device back to read mode within TRC. This prevents accidental writes during power-up, reset, or noise events. The SST39LF020-55-4I-WHE implements this per JEDEC standard and validates each byte of the sequence before initiating internal operations.
Can SST39LF020-55-4I-WHE be used as a direct replacement for 27C020 EPROM?
Yes, the SST39LF020-55-4I-WHE is pin- and command-compatible with the 27C020 EPROM in 32-pin PLCC packages. It matches the 256K × 8 organization, JEDEC-standard x8 pinout, and read-mode behavior. Unlike the 27C020, it requires no UV erasure and supports in-system electrical erase/program. However, firmware must implement the unlock sequences - the SST39LF020-55-4I-WHE does not emulate EPROM write timing and requires explicit command initiation.
What is the sector architecture of SST39LF020-55-4I-WHE?
The SST39LF020-55-4I-WHE contains sixty-four uniform 4 KByte sectors (256 KB ÷ 4 KB = 64), addressed using A12–A16. Sector-erase is initiated by loading the sector address on AMS–A12 lines during the final bus cycle of the six-byte erase command. Each sector can be erased independently, enabling modular firmware updates without affecting unrelated code or data. This architecture is identical across all SST39LF/VF010/020/040 devices, and the SST39LF020-55-4I-WHE implements it with guaranteed 18 ms typical erase time per sector.
SST39LF020-55-4I-WHE Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- SST39 MPF™
- Package/Case:
- 32-TFSOP (0.488", 12.40mm Width)
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- FLASH
- Technology:
- FLASH
- Memory Size:
- 2Mbit
- Memory Organization:
- 256K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 20µs
- Access Time:
- 55 ns
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-TSOP
SST39LF020-55-4I-WHE FAQ
1.How can I place an order for SST39LF020-55-4I-WHE through Aetrix?
Please submit a Request for Quotation (RFQ) for SST39LF020-55-4I-WHE on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SST39LF020-55-4I-WHE reliable?
The price and inventory of SST39LF020-55-4I-WHE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SST39LF020-55-4I-WHE is usually 5 days.
3.What payment methods are accepted for SST39LF020-55-4I-WHE?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SST39LF020-55-4I-WHE transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SST39LF020-55-4I-WHE?
SST39LF020-55-4I-WHE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SST39LF020-55-4I-WHE order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SST39LF020-55-4I-WHE?
For technical support, including SST39LF020-55-4I-WHE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SST39LF020-55-4I-WHE requirements.
6.How does Aetrix verify that SST39LF020-55-4I-WHE is sourced from the original manufacturer or authorized distributors?
All SST39LF020-55-4I-WHE products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SST39LF020-55-4I-WHE meets industry standards.
7.What is the process for return or replacement of SST39LF020-55-4I-WHE?
All SST39LF020-55-4I-WHE units undergo pre-shipment inspection (PSI). If there is an issue with SST39LF020-55-4I-WHE, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SST39LF020-55-4I-WHE part is unused and in its original packaging.
Return procedure for SST39LF020-55-4I-WHE:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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