Microchip Technology 47L04T-I/ST

Overview

47L04T-I/ST from Microchip Technology is a 4 Kbit I²C serial EERAM combining 512 × 8-bit SRAM with integrated EEPROM backup, operating from 2.7V–3.6V, supporting up to 1 MHz I²C, 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 infotainment control modules for nonvolatile parameter storage during ignition cycling.

For engineers reviewing the 47L04T-I/ST datasheet, 47L04T-I/ST pinout, 47L04T-I/ST application, or 47L04T-I/ST equivalent, key selection criteria include VCC range (2.7–3.6 V), Auto-Store trip voltage (2.4–2.6 V), 8 ms max Store time, software/hardware store control, and AEC-Q100 qualification for extended temperature operation (-40°C to +125°C).

Technical Context

The 47L04T-I/ST implements a dual-memory architecture where SRAM serves as fast-access working memory and EEPROM provides high-endurance nonvolatile backup. Its I²C interface uses Schmitt-trigger inputs, supports cascading up to four devices, and enforces strict timing per SMBus v2.0 with 500 ns minimum clock high/low times.

Power management is handled through VCAP-based auto-store detection: when VCC falls below VTRIP (2.4–2.6 V), the device initiates automatic SRAM-to-EEPROM transfer. The STATUS register (address 00h) controls ASE (Auto-Store Enable), BP<2:0> (block protection), and AM (Array Modified) status, while the COMMAND register (55h) executes software Store (33h) and Recall (DDh) operations.

Key Specifications

Pinout & Package

47L04T-I/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 thermal performance in compact automotive PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with FM24CL04B-G and AT24C04D-SSHM-T, the 47L04T-I/ST uniquely combines instant SRAM access with EEPROM-level nonvolatility and autonomous power-loss response - making it optimal for systems requiring both speed and guaranteed state preservation without host intervention.

Availability

47L04T-I/ST is available at Aetrix Electronics and suitable for automotive body control, industrial PLC configuration, medical infusion pump calibration, and smart energy meter firmware storage requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for 47L04T-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 Inc. is a leading provider of microcontrollers, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 47L04T-I/ST belongs to Microchip's EERAM family - engineered specifically for applications needing SRAM-speed access with EEPROM-level nonvolatility and autonomous power-loss resilience in harsh environments.

FAQ

What is the function of the VCAP pin on the 47L04T-I/ST?

The VCAP pin on the 47L04T-I/ST connects to an external 5–6.8 µF capacitor that supplies energy during VCC collapse, enabling automatic SRAM-to-EEPROM store when VCC drops below 2.4–2.6 V. If VCAP is unconnected, the pin must be tied to VCC and Auto-Store disabled (ASE = 0) to prevent EEPROM corruption. This design eliminates reliance on backup batteries while ensuring deterministic nonvolatile backup in automotive and industrial systems using the 47L04T-I/ST.

How does the 47L04T-I/ST handle write protection?

The 47L04T-I/ST implements software-configurable write protection via three BP<2:0> bits in its STATUS register (00h), allowing selective locking of memory blocks - from none to the entire 512-byte array (e.g., BP<2:0> = 111 protects addresses 000h–1FFh). Protection is nonvolatile and persists across power cycles. Attempts to write to protected regions result in NACK after the data byte, halting the operation without incrementing the address pointer - a critical safeguard for firmware-critical data stored in the 47L04T-I/ST.

Can the 47L04T-I/ST operate at 1 MHz I²C speed across its full temperature range?

Yes, the 47L04T-I/ST supports 1 MHz I²C operation from -40°C to +125°C (Extended temperature grade), with guaranteed AC timing including 500 ns minimum SCL high/low times and 300 ns max rise/fall times. Its Schmitt-trigger inputs suppress noise on noisy automotive or industrial buses, and zero-cycle-delay reads/writes ensure deterministic throughput. This full-range 1 MHz capability is explicitly specified in DS20005371E and makes the 47L04T-I/ST suitable for high-speed configuration updates in real-time systems.

What happens if a Hardware Store (HS) pulse occurs during an active I²C transaction on the 47L04T-I/ST?

If an HS pulse occurs during an SRAM read or write operation on the 47L04T-I/ST, the ongoing I²C transaction is immediately aborted to prioritize the Store operation. The device stops acknowledging further bytes, releases SDA, and begins SRAM-to-EEPROM transfer within nanoseconds. After completion (≤8 ms), the 47L04T-I/ST resumes normal I²C responsiveness. This behavior is documented in Section 2.3.1 and ensures data integrity even during concurrent host access - a key reliability feature of the 47L04T-I/ST.

Is the 47L04T-I/ST pin-compatible with other devices in the 47XXX family?

Yes, the 47L04T-I/ST shares identical 8-lead TSSOP pinout, electrical characteristics, and register map with all members of the 47L04/47C04/47L16/47C16 family, including 47L04T-I/SN (SOIC) and 47L04-I/P (PDIP). Pin functions (VCAP, A1, A2, VSS, VCC, HS, SCL, SDA), timing, and command set are fully consistent. However, voltage range differs: 47L04 variants require 2.7–3.6 V, while 47C04 uses 4.5–5.5 V - so direct substitution requires matching VCC domain, but PCB layout remains unchanged for the 47L04T-I/ST.