Microchip Technology 47C04-E/ST

Overview

47C04-E/ST from Microchip Technology is a 4 Kbit I²C serial EERAM combining volatile SRAM (512 × 8) with nonvolatile EEPROM backup, operating at 4.5–5.5 V and supporting up to 1 MHz I²C clock. It enables automatic power-loss data retention via external capacitor-assisted Auto-Store and supports manual Store/Recall via hardware pin or software command. Used in industrial control modules where persistent memory state must survive unexpected power interruption.

For engineers reviewing the 47C04-E/ST datasheet, 47C04-E/ST pinout, 47C04-E/ST application, or 47C04-E/ST equivalent, this page delivers verified electrical specs, validated I²C timing compliance, confirmed 8-pin TSSOP package mapping, real-world store/recall latency values, and two field-tested alternative parts with documented functional trade-offs.

Technical Context

The 47C04-E/ST implements a dual-memory architecture: 512 × 8-bit SRAM for high-speed read/write access and EEPROM for nonvolatile backup. Its I²C interface complies with standard 100 kHz/400 kHz/1 MHz modes, features Schmitt-trigger inputs for noise immunity, and supports cascading up to four devices on one bus. The device uses a volatile STATUS register (00h) and write-only COMMAND register (55h) to manage software write protection, Auto-Store enable/disable, and event flagging.

Power management integrates VCAP-based Auto-Store triggering at VTRIP = 4.0–4.4 V, with recall initiated automatically on power-up or manually via HS pin pulse (≥150 ns) or software command. Store time is fixed at ≤8 ms; recall completes in ≤2 ms. The AM bit tracks SRAM modification status, and BP<2:0> bits enable configurable write protection across 1/64 to full array ranges.

Key Specifications

Pinout & Package

47C04-E/ST is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, RoHS-compliant, and rated for -40°C to +125°C extended temperature operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar EERAM applications.

Compared with 47C04-E/ST, 47L04-E/ST shifts voltage operation downward for 3.3 V compatibility but sacrifices 5 V robustness, while FM24CL04B-G replaces EEPROM-based store with F-RAM's instant write but removes dedicated hardware event signaling and Auto-Store trip control.

Availability

47C04-E/ST is available at Aetrix Electronics and suitable for industrial PLC data logging, automotive body control modules, medical infusion pump settings, and smart energy meter firmware parameters requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for 47C04-E/ST 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 Inc. is a leading provider of microcontrollers, analog components, and memory solutions, serving industrial, automotive, and communications markets since 1989.

The 47C04-E/ST belongs to Microchip's EERAM product line, designed specifically to replace discrete SRAM + EEPROM combinations in systems needing seamless, low-overhead nonvolatile data retention during power loss.

FAQ

What is the primary function of the 47C04-E/ST in a system?

The 47C04-E/ST serves as a serial EERAM that combines fast SRAM for active data manipulation with integrated EEPROM for nonvolatile backup. Its core function is to automatically preserve SRAM contents to EEPROM upon power loss using an external VCAP capacitor, then restore them on power-up-eliminating the need for host MCU-initiated save routines. This makes the 47C04-E/ST ideal for applications where data integrity must survive uncontrolled shutdowns without software intervention.

How does the 47C04-E/ST differ from a standard I²C EEPROM?

Unlike standard I²C EEPROMs, the 47C04-E/ST provides concurrent SRAM-like read/write performance (zero-cycle-delay reads/writes) plus automatic nonvolatile backup. Standard EEPROMs require explicit write commands with 5–10 ms latency per byte and lack volatile cache; the 47C04-E/ST allows unlimited SRAM writes at I²C speed and only invokes EEPROM store during power loss or manual trigger. This architecture reduces firmware complexity and improves real-time responsiveness compared to pure EEPROM solutions.

Can the 47C04-E/ST be used without connecting the VCAP pin?

Yes, but only if Auto-Store is disabled. Per the datasheet, if no capacitor is connected to VCAP, the pin must be tied to VCC and the ASE bit in the STATUS register must be cleared (ASE = 0) to prevent EEPROM corruption during power loss. In this configuration, the 47C04-E/ST operates as a standard I²C SRAM with optional software- or hardware-triggered store-retaining full functionality except automatic power-fail capture. Manual Store via HS pin or software command remains fully operational.

What is the purpose of the HS pin on the 47C04-E/ST?

The HS (Hardware Store) pin on the 47C04-E/ST provides a direct, low-latency method to initiate SRAM-to-EEPROM store independent of I²C traffic or firmware execution. A high-going pulse ≥150 ns triggers immediate store, completing within ≤8 ms. This is critical in safety-critical systems where host MCU may be unresponsive during fault conditions. The HS pin also sets the EVENT bit in the STATUS register, enabling the host to detect and log external store requests-functionality absent in standard EEPROMs or FRAMs.

Is the 47C04-E/ST pin-compatible with other devices in the 47XXX family?

Yes-the 47C04-E/ST shares identical 8-pin TSSOP pinout, I²C addressing scheme, and register map with 47L04-E/ST, 47C16-E/ST, and 47L16-E/ST. All variants use the same VCAP, A1/A2, VSS, VCC, HS, SCL, and SDA connections. However, density (4 Kbit vs 16 Kbit) and VCC range (4.5–5.5 V vs 2.7–3.6 V) differ, so substitution requires verification of voltage compatibility and memory size sufficiency. Pin-for-pin replacement is valid within the same voltage class and density tier.