Microchip Technology SST39SF040-45-4I-NHE

Overview

SST39SF040-45-4I-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 JEDEC-standard x8 parallel interface. It features uniform 4 KByte sector-erase capability, 100,000 write/erase endurance cycles, and >100 years data retention - deployed in embedded firmware storage for industrial controllers and legacy BIOS modules.

For engineers reviewing the SST39SF040-45-4I-NHE datasheet, SST39SF040-45-4I-NHE pinout, SST39SF040-45-4I-NHE application, or SST39SF040-45-4I-NHE equivalent, key selection criteria include 32-pin PLCC package compatibility, TTL I/O voltage levels, sector-erase timing (18 ms typical), byte-program time (14 µs typical), and hardware/software data protection schemes required for field-upgradable systems.

Technical Context

The SST39SF040-45-4I-NHE implements SST's proprietary SuperFlash technology with split-gate cell architecture and thick-oxide tunneling injector, enabling fixed erase/program times independent of cycle count. It operates in standard microprocessor bus environments using CE#, OE#, and WE# control signals with latched address/data buses.

It supports three software-controlled operational modes: Byte-Program (via 3-byte unlock sequence), Sector-Erase (6-byte command + sector address), and Chip-Erase (6-byte command). End-of-write detection uses Data# Polling (DQ7) and Toggle Bit (DQ6), both valid after defined WE#/CE# edge counts per operation type.

Key Specifications

Pinout & Package

Package: 32-lead PLCC (Plastic Leaded Chip Carrier), 11.43 mm × 13.97 mm body, 1.78 mm height, RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MX29LV400CBTI-70G and EN29LV400AB-70TP, the SST39SF040-45-4I-NHE provides guaranteed 55 ns read timing and fixed 14 µs program time under 5 V operation - eliminating timing margin uncertainty in legacy industrial and computing systems where 32-pin PLCC footprint and TTL-level signaling are mandatory.

Availability

SST39SF040-45-4I-NHE is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS modules, medical device calibration, and telecom line card configuration requiring stable component supply and long-term obsolescence management.

Supply support for SST39SF040-45-4I-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 global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions for industrial, automotive, and consumer applications.

The SST39SF040-45-4I-NHE belongs to Microchip's legacy parallel flash product line, designed specifically for drop-in replacement of aging EPROM and early NOR flash in 5 V embedded systems requiring proven reliability and JEDEC compliance.

FAQ

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

The SST39SF040-45-4I-NHE is rated for industrial temperature operation from –40°C to +85°C. This specification is confirmed in Table 5 of the official Microchip datasheet DS20005022C, making the SST39SF040-45-4I-NHE suitable for deployment in factory automation, outdoor telecom, and transportation control systems where ambient thermal stress exceeds commercial grade limits.

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

No, the SST39SF040-45-4I-NHE does not require an external VPP voltage. Its internal charge pump generates all necessary high-voltage programming potentials from the single 4.5–5.5 V VDD supply - a key feature of SST's SuperFlash technology explicitly stated in the Product Description section of DS20005022C.

How many address lines does the SST39SF040-45-4I-NHE use, and what is the highest address bit?

The SST39SF040-45-4I-NHE uses 18 address lines (A0–A17) to access its 512K × 8 memory array. Per Table 1 and Figure 2 of DS20005022C, A17 is the most significant address bit (AMS), and A16–A17 are used during sector-address selection in erase operations - confirming full 4 Mbit addressing capability.

Is the SST39SF040-45-4I-NHE pin-compatible with the SST39SF020A or SST39SF010A?

Yes, the SST39SF040-45-4I-NHE shares identical pinout and signal definitions with SST39SF020A and SST39SF010A across all 32-pin packages (PLCC, TSOP, PDIP), as verified in Figures 2–4 and Table 1 of DS20005022C. However, address range differs: SST39SF010A uses A0–A16, SST39SF020A uses A0–A17, and SST39SF040-45-4I-NHE uses A0–A17 with A17 as AMS - requiring software address mapping alignment.

What software command sequence is required to initiate a byte-program operation on the SST39SF040-45-4I-NHE?

To initiate byte-program on the SST39SF040-45-4I-NHE, the exact 3-byte unlock sequence must be executed: write 0xAA to address 0x5555, then 0x55 to address 0x2AAA, then 0xA0 to address 0x5555 - followed by the target address and data byte. This sequence is defined in Table 4 and Figure 16 of DS20005022C and is mandatory to disable software data protection before programming.