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Microchip Technology 93LC66B-I/ST
- Part No.:
- 93LC66B-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93LC66B-I/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:813
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Product details
Overview
93LC66B-I/ST from Microchip Technology Inc. is a 4 Kbit, 256 × 16-bit organization, low-voltage serial EEPROM with Microwire-compatible 3-wire interface (CS, CLK, DI/DO), operating from 2.5 V to 5.5 V over –40°C to +85°C industrial temperature range. It features self-timed erase/write cycles, automatic ERAL before WRAL, and Ready/Busy status via DO pin - used in embedded system configuration storage, sensor calibration data retention, and firmware parameter backup.
For engineers reviewing the 93LC66B-I/ST datasheet, 93LC66B-I/ST pinout, 93LC66B-I/ST application, or 93LC66B-I/ST equivalent, key selection criteria include 16-bit word width support, TSSOP-8 package compatibility, industrial-grade temperature operation, and Microwire protocol timing compliance at up to 2 MHz (VCC ≥ 2.5 V).
Technical Context
This device implements a synchronous serial Microwire interface with dedicated 16-bit memory organization - no ORG pin required. All instructions (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS) are executed via rising-edge clocked bit streams on DI, with status and data returned on DO. The internal auto-erase-before-write logic ensures data integrity without external erase sequencing.
Power-on data protection is enforced by a built-in voltage detector (VPOR = 1.5 V typical), disabling all write operations below threshold. Standby current is limited to 1 µA (I-temp), and the device supports sequential read mode when CS remains high across address boundaries.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (256 × 16-bit) - fixed x16 organization; no ORG pin needed for word-width selection |
| VCC range | 2.5 V to 5.5 V - supports single-supply operation in 3.3 V and 5 V systems |
| Temperature grade | Industrial (–40°C to +85°C) - qualified for extended commercial and industrial control environments |
| Interface | Microwire-compatible 3-wire serial (CS, CLK, DI/DO) - no separate chip select enable; no SPI mode |
| Write endurance | 1,000,000 erase/write cycles - enables long-term field reprogramming in telemetry and metering applications |
| Data retention | 200 years at +25°C - ensures nonvolatile storage integrity across product lifecycle without refresh |
| Max clock frequency | 2 MHz at VCC ≥ 2.5 V - defines maximum instruction throughput for real-time configuration updates |
Pinout & Package
93LC66B-I/ST is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch and exposed pad option (not electrically connected). Pin 1 is marked by laser dot; package conforms to JEDEC MO-153.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-high enable; must be held low ≥250 ns between instructions; initiates self-timed programming on falling edge |
| CLK | Serial Clock | Rising-edge synchronized I/O; clock can pause mid-transfer; no clock required during erase/write cycle |
| DI | Data Input | Accepts Start bit, opcode, address, and data; shares net with DO only if external series resistor used |
| DO | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z on CS falling edge |
| VSS | Ground | Reference for all I/O and internal logic; must be connected before VCC |
| NC | No Internal Connection | Pin 7 is unconnected - no PCB trace or pull-up/down required |
| VCC | Power Supply | 2.5–5.5 V supply; VPOR circuit disables writes below ~1.5 V |
| ORG | Organization Select | Not present on 93LC66B - permanently configured for 16-bit mode; pin 6 is NC |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates need for external timing control; TWC = 6 ms max per byte/word - simplifies host firmware |
| Automatic ERAL before WRAL | Guarantees full-array erase prior to bulk write - prevents partial-data corruption during firmware update |
| Ready/Busy polling via DO | Enables non-blocking host operation; DO low = active programming; avoids fixed delay loops |
| Power-on/off data protection | Hardware-enforced write inhibition below VPOR threshold - prevents inadvertent writes during brown-out |
| 1,000,000 endurance cycles | Supports >10 years of daily reconfiguration in industrial HMI or sensor node applications |
Applications
| Industrial Sensor Calibration Storage | Embedded System Configuration Memory |
|---|---|
Use Scenario: Storing factory-trimmed offset/gain coefficients for analog sensor front-ends in programmable logic controllers. IC Role / Device Role / Timing Role: Nonvolatile parameter register accessed during power-up initialization; 16-bit word width matches ADC resolution. Use Value: Eliminates need for external trimming potentiometers or OTP fuses; enables field recalibration via serial interface. | Use Scenario: Holding user-defined settings (network ID, baud rate, alarm thresholds) in HVAC controller firmware. IC Role / Device Role / Timing Role: Microwire-configurable configuration store; accessed asynchronously during boot or menu navigation. Use Value: Survives power loss without battery backup; supports >1M write cycles for frequent setting changes. |
| Firmware Parameter Backup | Smart Meter Data Logging Buffer |
Use Scenario: Backing up critical runtime parameters (e.g., last known state, fault counters) before MCU reset or deep sleep. IC Role / Device Role / Timing Role: Low-latency, deterministic write target; uses WRAL for atomic full-array save after power-fail detection. Use Value: Ensures recovery to valid operational state after unexpected shutdown; leverages auto-erase to prevent stale data. | Use Scenario: Recording time-stamped energy consumption snapshots in utility meters with limited RAM. IC Role / Device Role / Timing Role: Cyclic buffer managed by metering ASIC; 16-bit words store 16-bit ADC samples or accumulated kWh values. Use Value: 200-year data retention meets ANSI C12.22 requirements; TSSOP-8 footprint fits compact meter PCBs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66A-I/ST | Same package and voltage range, but 512 × 8-bit (x8) organization - requires two reads/writes per 16-bit value | Used where legacy 8-bit bus alignment or software compatibility with older x8 designs is required | Select only if system firmware expects 8-bit word access or memory map is constrained to byte-addressable layout |
| AT25040B-MAHL-T | SPI interface (4-wire), 512 × 8-bit, 1.8–5.5 V, same endurance and retention - no Microwire compatibility | Requires SPI master instead of Microwire; lacks ERAL/WRAL atomic commands; different instruction set | Choose when migrating to SPI-based platforms or when needing higher clock rates (up to 20 MHz) |
Compared with 93LC66A-I/ST, the 93LC66B-I/ST delivers native 16-bit efficiency and eliminates software bit-packing overhead; versus AT25040B-MAHL-T, it preserves Microwire protocol compatibility and integrated ERAL/WRAL functionality at the cost of lower max clock speed.
Availability
93LC66B-I/ST is available at Aetrix Electronics and suitable for industrial control systems, sensor calibration modules, and embedded configuration storage requiring stable component supply, long-term obsolescence management, and RoHS-compliant packaging.
Supply support for 93LC66B-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 components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93LC66B-I/ST belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for low-power, Microwire-compatible nonvolatile storage in space- and cost-constrained embedded systems.
FAQ
What is the memory organization of the 93LC66B-I/ST?
The 93LC66B-I/ST has a fixed 256 × 16-bit (4 Kbit) organization. Unlike 'C' variants, it does not use the ORG pin - its 16-bit word width is hardwired, eliminating external configuration logic and reducing BOM count. This makes it ideal for systems requiring aligned 16-bit parameter storage without runtime reconfiguration.
Does the 93LC66B-I/ST require an external pull-up resistor on the DO pin?
No, the 93LC66B-I/ST does not require an external pull-up on DO. The DO pin actively drives high/low during READ or Ready/Busy status reporting and enters High-Z when CS is low or during idle. However, if DI and DO are shorted on a shared bus, a 1–10 kΩ series resistor is recommended to prevent bus conflict during the dummy zero phase of READ.
What is the maximum clock frequency supported by the 93LC66B-I/ST at 3.3 V?
At VCC = 3.3 V (within 2.5–5.5 V range), the 93LC66B-I/ST supports a maximum clock frequency of 2 MHz. This is specified in Table 1-2 (A1) for 2.5 V ≤ VCC < 5.5 V. Exceeding this limit may cause instruction misreads or incomplete write cycles due to violated setup/hold times.
How does the 93LC66B-I/ST handle power loss during a write operation?
The 93LC66B-I/ST incorporates hardware-level power-loss protection: its internal voltage detector (VPOR ≈ 1.5 V) disables all write/erase functions when VCC drops below threshold. If power fails mid-cycle, the self-timed write aborts cleanly, leaving memory in a known valid state - no data corruption or partial writes occur.
Is the 93LC66B-I/ST pin-compatible with the 93LC66C-I/ST in TSSOP-8 package?
No, the 93LC66B-I/ST is not pin-compatible with the 93LC66C-I/ST in TSSOP-8. While both use the same 8-lead TSSOP footprint, Pin 6 is NC on the 93LC66B-I/ST but functions as ORG on the 93LC66C-I/ST. Connecting VCC or GND to Pin 6 on a 93LC66B-I/ST board risks undefined behavior or damage if routed to an active driver.
93LC66B-I/ST Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 4Kbit
- Memory Organization:
- 256 x 16
- Memory Interface:
- Microwire
- Clock Frequency:
- 2 MHz
- Write Cycle Time - Word, Page:
- 6ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
93LC66B-I/ST FAQ
1.How can I place an order for 93LC66B-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66B-I/ST 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 93LC66B-I/ST reliable?
The price and inventory of 93LC66B-I/ST are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93LC66B-I/ST is usually 5 days.
3.What payment methods are accepted for 93LC66B-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66B-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66B-I/ST?
93LC66B-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66B-I/ST 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 93LC66B-I/ST?
For technical support, including 93LC66B-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66B-I/ST requirements.
6.How does Aetrix verify that 93LC66B-I/ST is sourced from the original manufacturer or authorized distributors?
All 93LC66B-I/ST 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 93LC66B-I/ST meets industry standards.
7.What is the process for return or replacement of 93LC66B-I/ST?
All 93LC66B-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66B-I/ST, 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 93LC66B-I/ST part is unused and in its original packaging.
Return procedure for 93LC66B-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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