Microchip Technology SST39SF040-45-4C-NHE

Overview

SST39SF040-45-4C-NHE from Microchip Technology is a 4 Mbit (512K × 8) CMOS Multi-Purpose Flash memory IC with single 4.5–5.5V supply operation, 55 ns read access time, and uniform 4 KByte sector-erase architecture. It implements SST's SuperFlash technology for high reliability in embedded firmware storage applications such as BIOS/UEFI code storage in industrial control systems.

For engineers reviewing the SST39SF040-45-4C-NHE datasheet, SST39SF040-45-4C-NHE pinout, SST39SF040-45-4C-NHE application, or SST39SF040-45-4C-NHE equivalent, key selection criteria include JEDEC-standard x8 parallel interface compatibility, hardware/software data protection, 100,000-program/erase cycle endurance, and support for both CE#- and WE#-controlled erase/program timing.

Technical Context

This device uses a split-gate SuperFlash cell architecture with thick-oxide tunneling injector to achieve fixed erase/program times independent of accumulated cycles-unlike conventional flash technologies where timing degrades over endurance life. Its command set follows JEDEC-standard pinouts and software protocols, including three-byte unlock sequences for byte-program and six-byte sequences for sector/chip-erase.

Operation relies on TTL-compatible I/O with latched address/data buses, tri-state outputs controlled by CE# and OE#, and end-of-write detection via Data# Polling (DQ7) or Toggle Bit (DQ6). The device supports both CE#- and WE#-initiated operations with identical timing minima, enabling flexible microcontroller interface design without dedicated timing controllers.

Key Specifications

Pinout & Package

Package: 32-lead PLCC (Plastic Leaded Chip Carrier), RoHS-compliant, 11.43 mm × 13.97 mm footprint with J-bend leads suitable for through-hole or surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar parallel flash memory applications.

Compared with AM29LV040B-70EI and MX29LV040CTTC-70G, the SST39SF040-45-4C-NHE offers faster 55 ns read timing, true 5V-only operation without level shifters, and uniform 4 KByte sectors-making it optimal for legacy 5V industrial systems requiring fine-grained firmware updates.

Availability

SST39SF040-45-4C-NHE is available at Aetrix Electronics and suitable for industrial control, medical device bootloading, telecom configuration storage, and automotive ECU calibration applications requiring stable component supply and long-term obsolescence management.

Supply support for SST39SF040-45-4C-NHE 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 is a leading provider of microcontrollers, analog components, and memory solutions, acquired SST in 2010 to expand its nonvolatile memory portfolio.

The SST39SF040-45-4C-NHE belongs to Microchip's legacy parallel flash product line, designed specifically for cost-sensitive, high-reliability embedded systems requiring pin-compatible upgrades from EPROMs and earlier flash generations.

FAQ

What is the maximum operating temperature range for the SST39SF040-45-4C-NHE?

The SST39SF040-45-4C-NHE is rated for industrial temperature operation from -40°C to +85°C, as specified in Table 5 of the official Microchip datasheet DS20005022C. This range applies to all DC and AC characteristics, including 55 ns read access and 14 µs byte-program timing. Operation outside this range may result in undefined behavior or reduced endurance.

Does the SST39SF040-45-4C-NHE require an external VPP voltage for programming?

No, the SST39SF040-45-4C-NHE does not require an external VPP voltage. Its internal charge pump generates all necessary high-voltage programming signals from the single 4.5–5.5V VDD supply, as confirmed in the "Automatic Write Timing" feature list and Figure 1 block diagram. This eliminates the need for external high-voltage circuitry and simplifies system design compared to older EPROM or early flash devices.

How many address lines does the SST39SF040-45-4C-NHE use, and what is the MSB pin?

The SST39SF040-45-4C-NHE uses 18 address lines (A0–A17), with A17 serving as the most significant bit for its 512K × 8 organization. This is explicitly stated in Table 1 footnote ("AMS = A18 for SST39SF040") and verified in Figures 2–4 pin diagrams, where A17 appears on PLCC pin 24 and TSOP pin 29. A18 is not used and is marked NC.

Can the SST39SF040-45-4C-NHE be used as a direct replacement for the SST39SF020A in existing designs?

Yes, the SST39SF040-45-4C-NHE is pin-compatible and electrically compatible with the SST39SF020A, sharing identical pinout, voltage ranges, timing parameters, and command sets. However, the SST39SF040-45-4C-NHE adds A17 and extends the address space to 512K, so existing software must be modified to access the upper 2 Mbit-otherwise it will operate as a 2 Mbit device with unused capacity.

What are the valid methods to detect completion of a byte-program operation on the SST39SF040-45-4C-NHE?

The SST39SF040-45-4C-NHE supports two validated end-of-write detection methods: Data# Polling (monitoring DQ7 for transition from complement to true data) and Toggle Bit (monitoring DQ6 for cessation of toggling between 0 and 1). Both are enabled after the rising edge of the fourth WE# or CE# pulse and are detailed in Section 8 of DS20005022C. Polling must be performed on the same address being programmed.