Microchip Technology 47L04-I/ST

Overview

47L04-I/ST from Microchip Technology is a 4 Kbit (512 × 8) I²C serial EERAM combining volatile SRAM with nonvolatile EEPROM backup. It operates from 2.7V–3.6V, supports up to 1 MHz I²C, and delivers automatic power-loss data retention via VCAP capacitor-assisted store/recall. Used in industrial control modules where infrequent but critical parameter persistence is required across power cycles.

For engineers reviewing the 47L04-I/ST datasheet, 47L04-I/ST pinout, 47L04-I/ST application, or 47L04-I/ST equivalent, key selection factors include its 8 ms max store time, software/hardware-triggered store capability, 200 µA typical active current, and AEC-Q100-qualified extended temperature support up to +125°C.

Technical Context

The 47L04-I/ST implements a dual-memory architecture: 512 × 8-bit SRAM for high-speed read/write access and EEPROM for nonvolatile backup. Store operations transfer modified SRAM contents to EEPROM either automatically on VCC fall (via VCAP), manually via HS pin pulse, or through software command (0x33). Recall restores EEPROM data to SRAM on power-up or via software (0xDD).

I²C interface compliance includes 100 kHz/400 kHz/1 MHz modes, Schmitt-trigger inputs on SDA/SCL/HS for noise immunity, and cascading support for up to four devices. The STATUS register (address 0x00) controls ASE (Auto-Store Enable), BP<2:0> (block protection), and AM (Array Modified) flag-critical for deterministic store triggering and write security.

Key Specifications

Pinout & Package

47L04-I/ST is supplied in an 8-lead TSSOP package (ST suffix), measuring 4.4 mm × 3.0 mm × 1.2 mm, with standard SOIC-compatible footprint and gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 47L04-I/ST, the PDIP variant offers superior mechanical stability but higher profile and lower density; the SOIC version provides broader manufacturing ecosystem support while maintaining identical electrical behavior and timing.

Availability

47L04-I/ST is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical device design requiring stable component supply with guaranteed long-term availability and AEC-Q100 compliance.

Supply support for 47L04-I/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 is a U.S.-based semiconductor company specializing in microcontrollers, analog, FPGA, and memory solutions with emphasis on reliability and long-term product support.

The 47L04-I/ST belongs to Microchip's EERAM family, designed specifically to replace battery-backed SRAM and simplify nonvolatile data logging in resource-constrained embedded systems.

FAQ

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

The VCAP pin on the 47L04-I/ST connects to an external capacitor (5–6.8 µF) that supplies hold-up energy during VCC collapse. When VCC drops below the trip voltage (2.4–2.6 V), the 47L04-I/ST uses charge stored on VCAP to complete an automatic SRAM-to-EEPROM store operation. If VCAP is unconnected, Auto-Store must be disabled (ASE = 0) to prevent data corruption.

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

Unlike conventional I²C EEPROMs, the 47L04-I/ST integrates a full 512 × 8-bit SRAM array with instantaneous read/write access and zero write-cycle delay. Its EEPROM serves solely as backup storage - activated only during store/recall events. This eliminates EEPROM's inherent write latency (ms-scale) during normal operation, enabling real-time parameter updates without blocking the I²C bus.

Can the 47L04-I/ST be used without connecting the HS pin?

Yes - the HS pin is optional. The 47L04-I/ST functions fully using Auto-Store (via VCAP) or Software Store (0x33 command) alone. Leaving HS unconnected or tied to VSS disables hardware-triggered store. However, the EVENT flag in the STATUS register will remain inactive unless HS is driven high during valid operation (VCAP ≥ VTRIP and no ongoing store/recall).

What happens to the AM (Array Modified) bit during a Store operation on the 47L04-I/ST?

The AM bit in the 47L04-I/ST STATUS register is set to '1' whenever any byte is written to SRAM and cleared to '0' only upon successful completion of a Store or Recall operation. It acts as a volatile dirty-flag - essential for determining whether Auto-Store should execute. The bit is read-only and resets to '0' after power-on reset, requiring software or hardware initialization to reflect actual SRAM state.

Is the 47L04-I/ST pin-compatible with other devices in the 47XXX family?

Yes - all 47XXX variants (47L04, 47C04, 47L16, 47C16) share identical 8-pin TSSOP/SOIC/PDIP footprints and pin assignments. However, voltage ranges differ: 47L04-I/ST requires 2.7–3.6V, while 47C04 accepts 4.5–5.5V. Swapping them without adjusting VCC violates absolute maximum ratings and risks permanent damage.