My Inquiry
My Account
Microchip Technology 93LC66A-I/ST
- Part No.:
- 93LC66A-I/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93LC66A-I/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:927
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
93LC66A-I/ST from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, operating from 2.5V to 5.5V, rated for Industrial temperature range (−40°C to +85°C), and housed in an 8-lead TSSOP package. It features self-timed erase/write cycles, automatic ERAL before WRAL, and Ready/Busy status signaling via DO pin - used for configuration storage in microcontroller-based embedded systems.
For engineers reviewing the 93LC66A-I/ST datasheet, 93LC66A-I/ST pinout, 93LC66A-I/ST application, or 93LC66A-I/ST equivalent, key selection criteria include its fixed 8-bit organization (no ORG pin), 1 million erase/write endurance, >200-year data retention, and compatibility with legacy Microwire host controllers requiring minimal GPIO overhead.
Technical Context
The 93LC66A-I/ST implements a synchronous serial interface using CS, CLK, and DI/DO signals with start-bit detection and opcode-driven command execution. Its internal logic supports READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS instructions - all clocked on the rising edge of CLK, with DO providing either data output or Ready/Busy status depending on CS timing and instruction phase.
It uses CMOS EEPROM technology with on-chip charge-pump circuitry enabling write operations at VCC ≥ 2.5V. Power-on/off protection ensures data integrity during supply transitions, and the device powers up in EWDS (Erase/Write Disable) mode - requiring explicit EWEN before any programming operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit), fixed x8 organization - no ORG pin; simplifies host firmware by eliminating word-size configuration logic. |
| VCC range | 2.5V to 5.5V - supports direct interfacing with 3.3V and 5V microcontrollers without level-shifting. |
| Endurance | 1,000,000 erase/write cycles - suitable for frequent calibration or runtime parameter logging. |
| Data retention | >200 years at 25°C - ensures long-term reliability in unattended industrial equipment. |
| Write cycle time | 6 ms typical (TWC) - defines minimum interval between consecutive WRITE or ERASE commands. |
| Interface | Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - requires only 4 GPIOs and no external components for basic operation. |
| Temp range | Industrial: −40°C to +85°C - validated for use in factory automation, HVAC, and metering applications. |
Pinout & Package
8-lead TSSOP (ST) package with standard pinout: Pin 1 = CS, Pin 2 = CLK, Pin 3 = DI, Pin 4 = DO, Pin 5 = VSS, Pin 6 = NC, Pin 7 = ORG (NC on A-version), Pin 8 = VCC. ORG pin is internally disconnected on 93LC66A devices per datasheet Table 3-1 and Device Selection Table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-high enable; must be held low ≥250 ns between instructions; falling edge initiates self-timed write/erase on 93LC66A. |
| CLK | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcodes, addresses, and data; stoppable at any point. |
| DI | Data Input | Accepts start bit, instruction opcodes, address bits, and write data; tied high with CS to detect start condition. |
| DO | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z when CS goes low or during standby. |
| VSS | Ground | Reference for all I/O and internal circuitry; must be connected directly to system ground plane. |
| NC | No Connection | Pin 6 is unconnected; no internal bond wire - may be left floating or grounded per PCB layout best practice. |
| ORG | Organization Select | No internal connection on 93LC66A - permanently configured for 8-bit operation; not usable as GPIO. |
| VCC | Power Supply | Supplies core logic and EEPROM array; includes internal voltage detector (VPOR = 1.5V) for power-on reset behavior. |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates need for external timing control - host only waits for DO=high or polls status after CS toggle. |
| Automatic ERAL before WRAL | Guarantees full-array erase prior to bulk write, preventing stale data corruption without software intervention. |
| Power-on/off data protection | Hardware-level lockout below VPOR (1.5V) prevents partial writes during brown-out or power ramp-up. |
| Ready/Busy status on DO | Enables efficient polling instead of fixed delays - reduces average write latency in interrupt-driven systems. |
| Industry-standard 3-wire interface | Direct drop-in replacement for legacy Microwire EEPROMs; compatible with existing driver libraries for PIC, AVR, and ARM MCUs. |
Applications
| Smart Meter Calibration Storage | Industrial PLC Configuration Memory |
|---|---|
Use Scenario: Storing meter-specific calibration coefficients, tariff tables, and firmware version metadata across power cycles. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed infrequently but requiring guaranteed write integrity and long-term retention. Use Value: 1M endurance and >200-year retention ensure field-deployed meters retain accuracy over full product lifetime without recalibration. | Use Scenario: Holding user-defined I/O mapping, PID loop parameters, and alarm thresholds in programmable logic controllers. IC Role / Device Role / Timing Role: Serial configuration EEPROM interfaced to PLC's main MCU via GPIO bit-banged Microwire. Use Value: Fixed 8-bit organization simplifies firmware implementation; 2.5–5.5V operation matches wide-input PLC power rails. |
| Medical Device Settings Backup | Automotive Body Control Module NVM |
Use Scenario: Preserving user-adjusted therapy settings, language preferences, and audit logs in portable diagnostic equipment. IC Role / Device Role / Timing Role: Low-power serial EEPROM supporting battery-backed operation during AC power loss. Use Value: Standby current ≤5 µA (ICCS) extends backup battery life; industrial temp rating covers clinical environment variations. | Use Scenario: Storing door lock logic, mirror position presets, and lighting profiles in automotive BCMs. IC Role / Device Role / Timing Role: Microwire EEPROM integrated into CAN/LIN subsystem for non-critical parameter storage. Use Value: Pb-free RoHS-compliant TSSOP package meets automotive sourcing requirements; 8-pin footprint minimizes board area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66B-I/ST | 16-bit organization (256 × 16), same VCC/temp/package - ORG pin is NC; incompatible data width. | Requires host firmware rework to handle 16-bit reads/writes; unsuitable where 8-bit alignment is enforced by protocol. | Select only if system architecture mandates 16-bit memory access and buffer alignment. |
| AT25040B-SSHL-T | 4 Kbit SPI interface (4-wire), 1.8–5.5V, 1M endurance, SOIC-8 - different protocol, no Ready/Busy pin. | Lacks DO-based status polling; relies on WIP flag in status register - increases software complexity for timing-critical writes. | Choose when migrating to SPI ecosystem or needing lower VCC min; verify driver compatibility. |
Compared with 93LC66B-I/ST, the 93LC66A-I/ST avoids 16-bit data path redesign; versus AT25040B-SSHL-T, it retains simpler status monitoring and Microwire legacy support - critical for cost-sensitive, firmware-constrained designs.
Availability
93LC66A-I/ST is available at Aetrix Electronics and suitable for smart meter calibration storage, industrial PLC configuration memory, and medical device settings backup requiring stable component supply across multi-year production cycles.
Supply support for 93LC66A-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, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 93LC66A-I/ST belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for low-pin-count, low-power, nonvolatile memory applications in resource-constrained embedded systems where simplicity, reliability, and long-term data integrity are essential.
FAQ
What is the memory organization of the 93LC66A-I/ST?
The 93LC66A-I/ST has a fixed 512 × 8-bit (4 Kbit) organization. Unlike 'C' variants, it lacks an ORG pin and is permanently configured for 8-bit operation - no external logic is needed to select word size. This simplifies hardware design and firmware handling compared to configurable versions like 93LC66C.
Does the 93LC66A-I/ST require an external pull-up resistor on the DO pin?
Yes, the 93LC66A-I/ST DO pin is open-drain and requires an external pull-up resistor (typically 4.7 kΩ to VCC) to ensure valid logic-high levels during Read and Ready/Busy status reporting. Without it, DO remains undefined during High-Z periods and cannot reliably signal device readiness.
How does the 93LC66A-I/ST handle power loss during a write operation?
The 93LC66A-I/ST incorporates hardware power-loss protection: its internal voltage detector (VPOR = 1.5V) disables all write/erase functions when VCC drops below this threshold. This prevents partial writes and ensures data integrity - no software recovery routine is required after brown-out events.
Can the 93LC66A-I/ST be used with a 1.8V microcontroller?
No, the 93LC66A-I/ST requires a minimum VCC of 2.5V per its Electrical Characteristics table. For 1.8V systems, consider the 93AA66A-I/ST (1.8–5.5V range) instead - it shares identical pinout, instruction set, and 8-bit organization but supports lower voltage operation.
Is the ORG pin functional on the 93LC66A-I/ST?
No, the ORG pin is marked "NC" (No Connection) on the 93LC66A-I/ST per the Device Selection Table and Pin Function Table. It is internally unconnected and must be left floating or tied to VSS/VCC - it has no effect on memory organization, which is fixed at 8-bit for all 'A' variants including 93LC66A-I/ST.
93LC66A-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:
- 512 x 8
- 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
93LC66A-I/ST FAQ
1.How can I place an order for 93LC66A-I/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66A-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 93LC66A-I/ST reliable?
The price and inventory of 93LC66A-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 93LC66A-I/ST is usually 5 days.
3.What payment methods are accepted for 93LC66A-I/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66A-I/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66A-I/ST?
93LC66A-I/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66A-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 93LC66A-I/ST?
For technical support, including 93LC66A-I/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66A-I/ST requirements.
6.How does Aetrix verify that 93LC66A-I/ST is sourced from the original manufacturer or authorized distributors?
All 93LC66A-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 93LC66A-I/ST meets industry standards.
7.What is the process for return or replacement of 93LC66A-I/ST?
All 93LC66A-I/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66A-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 93LC66A-I/ST part is unused and in its original packaging.
Return procedure for 93LC66A-I/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
93LC66A-I/ST Tags
-
M24C02-WMN6TP
STMicroelectronics
-
AT24C02C-XHM-T
Microchip Technology
-
AT21CS01-STUM10-T
Microchip Technology
-
AT24C02C-SSHM-T
Microchip Technology
-
24LC01BT-I/OT
Microchip Technology
-
M24C02-FMC6TG
STMicroelectronics
-
AT24CS02-SSHM-T
Microchip Technology
-
93LC46BT-I/OT
Microchip Technology
-
AT24C04C-SSHM-T
Microchip Technology
-
24LC01BT-I/SN
Microchip Technology
-
24AA02UIDT-I/OT
Microchip Technology
-
AT24C08C-STUM-T
Microchip Technology
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
