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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Microchip Technology 48L640T-I/SN

Name: 48L640T-I/SN
Brand: Microchip Technology
SKU: 48L640T-I/SN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 48L640T-I/SN

Manufacturer:: Microchip Technology

Category:: Memory

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: 48L640T-I/SN.pdf

Description:: IC EERAM 64KBIT SPI 66MHZ 8SOIC

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Product details

Overview

48L640T-I/SN from Microchip Technology Inc. is a 64-Kbit serial EERAM combining an 8,192 × 8-bit SRAM core with integrated cell-based EEPROM backup, operating over 2.7V–3.6V at -40°C to +85°C. It delivers symmetrical SPI read/write up to 66 MHz, supports AutoStore/AutoRecall on power loss, and uses a 33 μF external VCAP capacitor for seamless nonvolatile data retention in industrial control and metering applications.

For engineers reviewing the 48L640T-I/SN datasheet, 48L640T-I/SN pinout, 48L640T-I/SN application, or 48L640T-I/SN equivalent, key selection considerations include its unlimited SRAM endurance, 3 μA hibernate current, VCAP-based power-fail protection timing (2.30–2.65 V trip), 100,000 store cycles, and dual SPI Mode 0/3 compatibility - all critical for fail-safe data logging in unattended embedded systems.

Technical Context

The 48L640T-I/SN implements a true SRAM interface with invisible, parallel SRAM-to-EEPROM backup triggered by VCC monitoring. Its internal VCC monitor detects drops below 2.30–2.65 V, suspends I/O, and transfers the full 8K×8 array using energy stored in the external VCAP capacitor - no host intervention required.

It operates exclusively as an SPI slave with Mode 0 and Mode 3 support (SCK idle low/high), MSb-first data framing, and hardware HOLD functionality that pauses ongoing transfers without resetting sequence state. The STATUS register includes volatile WEL and RDY/BSY bits plus nonvolatile BP[1:0], ASE, and PRO bits for write protection and page rollover control.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Type	Serial EERAM: 8,192 × 8-bit SRAM + integrated cell-mirrored EEPROM backup
Interface	SPI slave, Modes 0 & 3 only; MSb-first; 3-wire + CS + HOLD; Schmitt-trigger inputs
Max Clock Frequency	66 MHz - enables high-throughput data buffering without wait states
Power Supply	2.7V–3.6V - compatible with 3.3V industrial logic rails and brown-out tolerant
Current Consumption	5 mA active (max), 200 μA standby (85°C), 3 μA hibernate (85°C) - supports ultra-low-power sleep modes
Backup Endurance	100,000 store cycles minimum at 85°C - ensures long-term reliability in frequent power-cycle environments
Data Retention	100 years at 55°C, 10 years at 85°C - meets archival requirements for metering and telemetry logs
VCAP Requirement	22 μF typical (10–50 μF, 6.3V+ rated) - provides ~200 μs of autonomous power for full-array store operation

Pinout & Package

48L640T-I/SN is supplied in an 8-lead SOIC package (3.9 mm × 4.9 mm, 1.27 mm pitch) with standard JEDEC outline and RoHS-compliant matte tin lead finish.

Pin/Terminal	Circuit Role	Design Meaning
CS	Chip Select Input	Active-low enable; forces SO into high-Z when deasserted; required high-to-low transition before any command
SO	Serial Data Output	MSb-first output; data valid after falling SCK edge; tri-states immediately on HOLD low
VCAP	External Capacitor Terminal	Connects to 22 μF (min) capacitor; supplies energy for autonomous SRAM→EEPROM store during VCC drop
VSS	Ground Reference	System ground return; exposed pad on TDFN variant may be connected to VSS or left floating
SI	Serial Data Input	MSb-first input; latches data on rising SCK edge; ignored during HOLD mode
SCK	Serial Clock Input	Master-generated clock; defines SPI Mode 0 (idle low) or Mode 3 (idle high); rise/fall time ≤100 ns
HOLD	Hold Input	Pauses ongoing SPI transfer without resetting state; must be asserted during SCK low pulse to activate
VCC	Supply Voltage	2.7V–3.6V main power; monitored internally for AutoStore trigger at 2.30–2.65 V threshold

Key Features

Feature	Design Value
Unlimited SRAM Read/Write Cycles	True SRAM behavior - no wear leveling or erase limitations; ideal for high-frequency buffer applications
Autonomous Power-Fail Backup	No firmware or host action needed: VCC monitoring + VCAP energy storage enables zero-intervention SRAM→EEPROM store
16-Bit Nonvolatile User Space	Dedicated 2-byte field for calibration constants or device IDs; written/verified atomically and backed up with SRAM
Hardware HOLD Function	Preserves partial command state during bus arbitration; eliminates retransmission overhead in multi-master systems
Configurable Block Write Protection	BP[1:0] bits in STATUS register enable selective SRAM region locking (none, upper quarter, half, or full array)
Secure Read/Write with CRC	12.5% overhead (32-byte payload + 2-byte CRC) prevents undetected memory corruption in safety-critical contexts

Applications

Smart Energy Metering	Industrial PLC Data Logging
Use Scenario: Storing cumulative kWh readings, tariff schedules, and event timestamps across frequent mains interruptions. IC Role / Device Role / Timing Role: Fail-safe SRAM buffer with automatic EEPROM backup on brown-out; replaces battery-backed SRAM. Use Value: Eliminates coin-cell batteries and associated leakage, calendar-life, and RoHS compliance concerns while guaranteeing data integrity through >100,000 power cycles.	Use Scenario: Capturing sensor history, fault codes, and configuration snapshots in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: Nonvolatile scratchpad memory interfaced directly to ARM Cortex-M SPI peripheral with HOLD support for deterministic interrupt response. Use Value: Enables sub-200 μs power-loss recovery via VCAP-assisted AutoRecall, meeting IEC 61131-2 reaction time requirements for safety-rated controllers.
Medical Infusion Pump Memory	Automotive Telematics Event Buffer
Use Scenario: Recording dose history, alarm logs, and calibration parameters in Class II medical devices requiring FDA 21 CFR Part 11 audit trails. IC Role / Device Role / Timing Role: Secure, tamper-evident memory with CRC-protected reads/writes and 100-year data retention at 55°C. Use Value: Meets regulatory retention mandates without external ECC or redundant storage, reducing BOM count and validation scope.	Use Scenario: Buffering GPS coordinates, CAN bus diagnostics, and crash-event pre-trigger data in telematics control units subject to vehicle battery disconnect. IC Role / Device Role / Timing Role: High-speed SPI memory (66 MHz) with 3 μA hibernate current, enabling always-on monitoring with minimal parasitic drain. Use Value: Extends backup runtime during ignition-off periods while ensuring critical crash data survives 100% of power-loss events per ISO 16750-2.

Smart Energy Metering

Industrial PLC Data Logging

Use Scenario: Storing cumulative kWh readings, tariff schedules, and event timestamps across frequent mains interruptions.

IC Role / Device Role / Timing Role: Fail-safe SRAM buffer with automatic EEPROM backup on brown-out; replaces battery-backed SRAM.

Use Value: Eliminates coin-cell batteries and associated leakage, calendar-life, and RoHS compliance concerns while guaranteeing data integrity through >100,000 power cycles.

Use Scenario: Capturing sensor history, fault codes, and configuration snapshots in programmable logic controllers deployed in factory automation.

IC Role / Device Role / Timing Role: Nonvolatile scratchpad memory interfaced directly to ARM Cortex-M SPI peripheral with HOLD support for deterministic interrupt response.

Use Value: Enables sub-200 μs power-loss recovery via VCAP-assisted AutoRecall, meeting IEC 61131-2 reaction time requirements for safety-rated controllers.

Medical Infusion Pump Memory

Automotive Telematics Event Buffer

Use Scenario: Recording dose history, alarm logs, and calibration parameters in Class II medical devices requiring FDA 21 CFR Part 11 audit trails.

IC Role / Device Role / Timing Role: Secure, tamper-evident memory with CRC-protected reads/writes and 100-year data retention at 55°C.

Use Value: Meets regulatory retention mandates without external ECC or redundant storage, reducing BOM count and validation scope.

Use Scenario: Buffering GPS coordinates, CAN bus diagnostics, and crash-event pre-trigger data in telematics control units subject to vehicle battery disconnect.

IC Role / Device Role / Timing Role: High-speed SPI memory (66 MHz) with 3 μA hibernate current, enabling always-on monitoring with minimal parasitic drain.

Use Value: Extends backup runtime during ignition-off periods while ensuring critical crash data survives 100% of power-loss events per ISO 16750-2.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
48L640T-I/MNY	Same die, 8-pad TDFN (3 mm × 2 mm) package; identical electrical specs and timing; requires different PCB footprint and thermal relief design	Better suited for space-constrained portable designs where SOIC height or board area is prohibitive	Select 48L640T-I/MNY only when layout density or profile constraints justify requalification of solder joint reliability and thermal performance.
FM25V05-G	F-RAM-based (not EERAM); 512 Kbit density; 3.3V-only; no VCAP capacitor required; 10¹⁴ read/write endurance vs. SRAM-only endurance	Eliminates power-fail timing dependency but lacks cell-level EEPROM mirroring; retention relies on ferroelectric polarization stability	Choose FM25V05-G when ultra-high endurance (>10¹² cycles) and zero-capacitor simplicity outweigh the need for guaranteed 100-year archival retention at elevated temperature.

Compared with 48L640T-I/SN, the 48L640T-I/MNY offers identical functionality in a smaller footprint but demands revised layout and requalification, while the FM25V05-G trades VCAP-dependent reliability for F-RAM's inherent nonvolatility - making it suitable for high-cycle-rate logging but less optimal for long-term archival under thermal stress.

Availability

48L640T-I/SN is available at Aetrix Electronics and suitable for smart metering, industrial PLC data logging, medical infusion pump memory, and automotive telematics event buffering requiring stable component supply, long-lifecycle assurance, and fail-safe nonvolatile storage.

Supply support for 48L640T-I/SN 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 manufacturer specializing in microcontrollers, analog devices, and memory solutions for industrial, automotive, and communications markets.

The 48L640T-I/SN belongs to Microchip's EERAM product line, designed specifically to replace battery-backed SRAM in mission-critical embedded systems where maintenance-free, long-retention, and power-loss resilience are mandatory.

FAQ

What is the primary function of the VCAP pin on the 48L640T-I/SN?

The VCAP pin on the 48L640T-I/SN connects to an external 22 μF (10–50 μF) capacitor that stores charge during normal operation. When VCC drops below 2.30–2.65 V, the device uses this stored energy to autonomously transfer the entire 8K×8 SRAM array to its integrated EEPROM cells - ensuring zero-data-loss power failover without host involvement. This makes the 48L640T-I/SN a direct replacement for battery-backed SRAM in industrial and metering applications.

Does the 48L640T-I/SN require a write-enable command before every SRAM write operation?

Yes, the 48L640T-I/SN requires execution of the WREN (06h) instruction to set the Write Enable Latch (WEL) bit before each WRITE or WRSR command. The WEL bit resets to '0' after any write completes, on power-up, or upon WRDI execution. This hardware-enforced write protection prevents accidental overwrites - a critical safeguard in systems like smart meters where firmware bugs or noise could corrupt logged data. The 48L640T-I/SN enforces this at the silicon level, independent of software state.

Can the 48L640T-I/SN be used with SPI Mode 1 or Mode 2 interfaces?

No, the 48L640T-I/SN supports only SPI Modes 0 and 3 - defined by data sampling on the rising SCK edge and output on the falling edge. Modes 1 and 2 (which sample on falling edges) are not electrically or functionally supported. Attempting to use Mode 1 or 2 will result in corrupted reads/writes because the 48L640T-I/SN's internal timing logic is hardwired for rising-edge capture. System designers must configure their SPI master accordingly; the 48L640T-I/SN datasheet explicitly states compatibility is limited to these two modes.

How does the HOLD function behave during an active SRAM write cycle on the 48L640T-I/SN?

The HOLD function on the 48L640T-I/SN has no effect on an ongoing SRAM write cycle - it only pauses serial command/data transfer. If a WRITE instruction is in progress when HOLD is asserted, the internal write completes normally using SRAM's inherent speed; the HOLD signal merely halts further SPI communication until deasserted. This ensures data integrity: partial writes cannot be interrupted, and the 48L640T-I/SN guarantees atomic 1-byte SRAM updates. The HOLD pin remains functional for pausing subsequent commands without affecting already-executing operations.

What is the purpose of the 16-bit nonvolatile user space in the 48L640T-I/SN?

The 16-bit nonvolatile user space in the 48L640T-I/SN provides a dedicated, independently addressable 2-byte field for storing device-specific constants - such as factory calibration offsets, unique serial numbers, or security keys - that must survive power cycles and align with SRAM data retention. It is written/verified atomically via WRNUR/C2h and read via RDNUR/C3h, and its contents are automatically backed up alongside SRAM and STATUS register during AutoStore or Software Store operations - ensuring synchronized, tamper-resistant persistence without consuming SRAM address space.

48L640T-I/SN Specifications

Product attributes: Attribute value

Manufacturer:: Microchip Technology

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Programmable:: Not Verified

Memory Type:: Non-Volatile

Memory Format:: EERAM

Technology:: EEPROM, SRAM

Memory Size:: 64Kbit

Memory Organization:: 8K x 8

Memory Interface:: SPI

Clock Frequency:: 66 MHz

Write Cycle Time - Word, Page:: -

Access Time:: -

Voltage - Supply:: 2.7V ~ 3.6V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

48L640T-I/SN FAQ

1.How can I place an order for 48L640T-I/SN through Aetrix?

Please submit a Request for Quotation (RFQ) for 48L640T-I/SN on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 48L640T-I/SN reliable?

The price and inventory of 48L640T-I/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 48L640T-I/SN is usually 5 days.

3.What payment methods are accepted for 48L640T-I/SN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 48L640T-I/SN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 48L640T-I/SN?

48L640T-I/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 48L640T-I/SN order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 48L640T-I/SN?

For technical support, including 48L640T-I/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 48L640T-I/SN requirements.

6.How does Aetrix verify that 48L640T-I/SN is sourced from the original manufacturer or authorized distributors?

All 48L640T-I/SN products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 48L640T-I/SN meets industry standards.

7.What is the process for return or replacement of 48L640T-I/SN?

All 48L640T-I/SN units undergo pre-shipment inspection (PSI). If there is an issue with 48L640T-I/SN, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 48L640T-I/SN part is unused and in its original packaging.

Return procedure for 48L640T-I/SN:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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