Microchip Technology 47C04T-I/ST

Overview

47C04T-I/ST from Microchip Technology is a 4 Kbit I²C serial EERAM combining SRAM (512 × 8) with EEPROM backup, supporting automatic power-loss data retention via VCAP capacitor, hardware Store pin (HS), and software-controlled Store/Recall commands. It operates at 4.5–5.5 V, delivers 1 MHz I²C interface speed, and targets industrial data logging in programmable logic controllers and sensor nodes requiring nonvolatile memory with infinite SRAM write endurance.

For engineers reviewing the 47C04T-I/ST datasheet, 47C04T-I/ST pinout, 47C04T-I/ST application, or 47C04T-I/ST equivalent, key selection criteria include its 4.5–5.5 V supply range, 8 ms max Store time, Schmitt-triggered I²C inputs, software-configurable write protection (1/64 to full array), and AEC-Q100-qualified temperature range (–40°C to +85°C).

Technical Context

The 47C04T-I/ST implements a dual-memory architecture where volatile SRAM enables high-speed read/write access while embedded EEPROM provides nonvolatile backup. Its I²C client interface uses fixed 4-bit op codes (1010 for SRAM, 0011 for control registers) and supports cascading up to four devices via A1/A2 address pins.

Power-loss handling relies on external VCAP capacitance (4.7 µF typical) triggering Auto-Store when VCC falls below 4.0–4.4 V trip voltage; recall occurs automatically on power-up. The STATUS register (address 00h) manages AM (Array Modified), ASE (Auto-Store Enable), BP (Block Protect), and EVENT flags - all nonvolatile except AM.

Key Specifications

Pinout & Package

47C04T-I/ST is housed in an 8-lead TSSOP package (3.0 mm × 4.4 mm, 0.65 mm pitch), optimized for space-constrained industrial PCBs and reflow-compatible assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 47C04T-I/ST, the 47L04T-I/ST offers lower-voltage compatibility at the cost of 5 V incompatibility, while the FM24CL04B-G trades Auto-Store automation and speed for unlimited endurance and simpler power design - making each suitable for distinct subsystem voltage and reliability priorities.

Availability

47C04T-I/ST is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and smart metering applications requiring stable component supply, long-lifecycle support, and AEC-Q100-qualified performance.

Supply support for 47C04T-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 microcontroller, analog, FPGA, and memory solutions, serving industrial, automotive, and communications markets with vertically integrated silicon and development tools.

The 47C04T-I/ST belongs to Microchip's EERAM product line - designed specifically to replace battery-backed SRAM and discrete EEPROM+SRAM combinations in systems demanding seamless, low-power, nonvolatile data retention without external support components.

FAQ

What is the function of the VCAP pin on the 47C04T-I/ST?

The VCAP pin on the 47C04T-I/ST connects to an external 4.7 µF capacitor that supplies hold-up energy during power loss, enabling automatic Store of SRAM contents to EEPROM. If VCAP is left unconnected, Auto-Store must be disabled (ASE = 0) and VCAP tied to VCC to prevent EEPROM corruption - the 47C04T-I/ST will not operate correctly without proper VCAP configuration per DS20005371E.

How does the 47C04T-I/ST handle I²C address conflicts when multiple devices share the same bus?

The 47C04T-I/ST uses user-configurable A1 and A2 pins to set the two least-significant bits of its 7-bit I²C slave address (base 1010xx0), allowing up to four 47C04T-I/ST devices on one bus. Address matching is strict: the device only responds if both A1/A2 pin levels match the corresponding bits in the received control byte - no software address reassignment is possible on the 47C04T-I/ST.

Can the 47C04T-I/ST perform Store operations without an external capacitor?

Yes - the 47C04T-I/ST supports manual Store via its Hardware Store (HS) pin or Software Store command (0x33 to COMMAND register), both of which function independently of VCAP. However, Auto-Store on power-down requires the external capacitor; omitting it disables that feature but does not impair HS- or software-initiated Store operations on the 47C04T-I/ST.

What is the maximum allowable bus capacitance for reliable I²C communication with the 47C04T-I/ST?

The 47C04T-I/ST specifies a maximum bus capacitance of 400 pF for compliant I²C operation at 1 MHz. Exceeding this value increases rise/fall times beyond the 300 ns limit, risking setup/hold violations and communication errors. Designers must account for PCB trace capacitance, connector parasitics, and other I²C device loads when routing the SDA/SCL lines for the 47C04T-I/ST.

How does write protection work on the 47C04T-I/ST, and what memory ranges can be protected?

Write protection on the 47C04T-I/ST is controlled by BP2–BP0 bits in the STATUS register, enabling protection of 1/64 (1F8h–1FFh) up to the full 512-byte SRAM array. Protection is enforced at the hardware level: writes to locked regions receive no ACK and abort immediately. The BP bits are nonvolatile, retaining settings across power cycles - a key reliability feature of the 47C04T-I/ST.