Microchip Technology 47L04-E/ST

Overview

47L04-E/ST from Microchip Technology is a 4 Kbit I²C serial EERAM combining 512 × 8-bit SRAM with integrated EEPROM backup, operating from 2.7V to 3.6V, supporting up to 1 MHz I²C interface, and featuring automatic power-loss store/recall via external VCAP capacitor. It delivers infinite SRAM write cycles, >1 million EEPROM store cycles, and >200-year data retention - deployed in automotive body control modules for nonvolatile parameter storage during ignition cycling.

For engineers reviewing the 47L04-E/ST datasheet, 47L04-E/ST pinout, 47L04-E/ST application, or 47L04-E/ST equivalent, key selection considerations include its 8-pin TSSOP package, hardware store (HS) pin support, ASE/AM bit-controlled auto-store behavior, and software-configurable SRAM write protection down to 1/64 of the array.

Technical Context

The 47L04-E/ST implements a dual-memory architecture where volatile SRAM serves as primary working memory and nonvolatile EEPROM provides persistent backup. Store and recall operations are triggered either automatically on VCC fall/rise (when ASE = 1 and VCAP ≥ VTRIP), manually via HS pin pulse (≥150 ns), or through software commands (0x55 + 0x33 for Store, 0x55 + 0xDD for Recall).

Its I²C interface complies with standard 100 kHz / 400 kHz / 1 MHz modes, uses Schmitt-trigger inputs on SDA/SCL/HS for noise immunity, supports cascading up to four devices via A1/A2 address pins, and enforces strict timing: THD:STA ≥ 250 ns, TSU:DAT ≥ 100 ns, and TSTORE ≤ 8 ms for full 4 Kbit store.

Key Specifications

Pinout & Package

47L04-E/ST is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, JEDEC MO-153 compliant, suitable for automated SMT assembly and space-constrained automotive ECUs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nonvolatile serial memory applications.

Compared with 47L04-I/ST, the 47L04-E/ST adds extended temperature qualification essential for engine bay deployment; versus FM24V04-G, it trades F-RAM speed and endurance for lower unit cost and proven EEPROM data retention stability over decades.

Availability

47L04-E/ST is available at Aetrix Electronics and suitable for automotive body control units, industrial PLCs, medical infusion pumps, and smart metering systems requiring stable component supply across multi-year production lifecycles.

Supply support for 47L04-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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with broad automotive and industrial certification coverage.

The 47L04-E/ST belongs to Microchip's EERAM family - designed specifically to replace discrete SRAM + EEPROM + power-monitoring IC combinations in space- and cost-constrained embedded systems requiring seamless nonvolatile data retention.

FAQ

What is the function of the VCAP pin on the 47L04-E/ST?

The VCAP pin on the 47L04-E/ST connects to an external 5–6.8 µF capacitor that supplies energy to complete the SRAM-to-EEPROM store operation during VCC dropout. When VCAP voltage falls below VTRIP (2.4–2.6V), auto-store initiates; the capacitor must hold sufficient charge to sustain ≤8 ms store duration. If unused, VCAP must be tied to VCC and ASE disabled to prevent EEPROM corruption.

How does the 47L04-E/ST differ from standard I²C EEPROMs?

Unlike standard I²C EEPROMs, the 47L04-E/ST integrates a 512 × 8-bit SRAM array with instant-read/write access and automatic background store/recall to EEPROM. It eliminates write-cycle delays (no 5–10 ms page-write waits), supports zero-cycle-delay I²C transfers, and offers infinite SRAM endurance - making it ideal for frequently updated configuration data that must survive power loss without MCU intervention.

Can the 47L04-E/ST be used without connecting the A1 and A2 pins?

No - A1 and A2 pins on the 47L04-E/ST must be hardwired to VSS or VCC to set the two least-significant bits of the 7-bit I²C client address (1010 A2 A1 0). Leaving them floating risks bus contention or unpredictable addressing. Valid combinations yield addresses 0x50–0x53; all four devices can share one I²C bus with unique A1/A2 configurations.

What happens if the HS pin is asserted during an ongoing I²C transaction?

If the HS pin is driven high during an active I²C read or write on the 47L04-E/ST, the current transaction is immediately aborted to execute the hardware store operation. The device stops acknowledging further bytes, halts SRAM access, and begins transferring SRAM contents to EEPROM. Once store completes (≤8 ms), normal I²C operation resumes - no data loss occurs, but the interrupted transaction must be reinitiated by the host.

Is the 47L04-E/ST pin-compatible with the 47C04 series?

Yes - the 47L04-E/ST shares identical 8-pin TSSOP pinout and signal mapping with the 47C04 series (e.g., 47C04-I/ST), but operates at different VCC ranges (2.7V–3.6V vs. 4.5V–5.5V) and has distinct VTRIP (2.4–2.6V vs. 4.0–4.4V). Direct substitution requires verifying system voltage compatibility and adjusting VCAP capacitance value per datasheet Table 1-1.