My Inquiry
My Account
Microchip Technology 93LC66A-E/ST
- Part No.:
- 93LC66A-E/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
93LC66A-E/ST.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,811
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
93LC66A-E/ST from Microchip Technology Inc. is a 4 Kbit (512 × 8-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 2.5–5.5 V supply range, and automotive-grade temperature operation (–40°C to +125°C). It features self-timed erase/write cycles, automatic ERAL before WRAL, power-on/off data protection, and Ready/Busy status signaling via DO pin - deployed in engine control units for calibration storage.
For engineers reviewing the 93LC66A-E/ST datasheet, 93LC66A-E/ST pinout, 93LC66A-E/ST application, or 93LC66A-E/ST equivalent, key selection criteria include its 8-bit fixed organization (no ORG pin), automotive qualification, 6 ms write cycle time, 1 million endurance cycles, and TSSOP-8 package compatibility with space-constrained PCB layouts.
Technical Context
The 93LC66A-E/ST implements a synchronous serial Microwire interface with CS, CLK, DI, and DO signals - no ORG pin (dedicated x8 mode). All instructions (READ, WRITE, ERASE, ERAL, WRAL, EWEN/EWDS) are initiated by a Start bit followed by opcode and address/data on rising CLK edges.
It uses internal auto-erase-before-write logic and supports sequential read. Ready/Busy status is polled via DO while CS is high after ≥250 ns low time (TCSL); DO goes High-Z on CS falling edge. Power-up default is EWDS mode, requiring explicit EWEN before programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (512 × 8-bit) - fixed x8 organization, no ORG pin required |
| VCC range | 2.5 V to 5.5 V - supports wide-input industrial and automotive rails |
| Endurance | 1,000,000 erase/write cycles - enables long-term field calibration updates |
| Data retention | 200 years at 25°C - ensures firmware parameter integrity over product lifetime |
| Write cycle time | 6 ms typical - defines minimum interval between successive WRITE commands |
| Operating temp | –40°C to +125°C (Automotive E grade) - qualified for under-hood ECUs and ADAS modules |
| Interface | Microwire 3-wire serial (CS/CLK/DI/DO) - minimal GPIO usage, no I²C pull-ups needed |
Pinout & Package
93LC66A-E/ST is packaged in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm pitch, JEDEC MO-153 compliant, Pb-free Matte Tin finish. Pin 1 marked by laser dot; body dimensions 3.0 mm × 4.4 mm × 1.2 mm max height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select | Active-high enable; must be held ≥250 ns low between instructions to reset internal logic |
| 2 (CLK) | Serial Clock | Synchronizes all data transfers; rising edge clocks in opcode/address/data; stoppable mid-sequence |
| 3 (DI) | Data Input | Accepts Start bit, instruction opcodes, addresses, and write data; tied to DO only with series resistor to avoid bus conflict |
| 4 (DO) | Data Output / Status | Outputs read data or Ready/Busy (low = busy); enters High-Z on CS falling edge |
| 5 (VSS) | Ground | Reference return path; decoupling capacitor required within 10 mm of pin |
| 6 (NC) | No Connect | Internally unconnected; must be left floating or tied to VSS per layout best practice |
| 7 (ORG) | Organization | No internal connection on 'A' devices - pin is NC and must not be driven |
| 8 (VCC) | Power Supply | 2.5–5.5 V input; POR threshold at 1.5 V ensures data protection during brown-out |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed erase/write | Eliminates external timing circuitry - internal state machine manages full auto-erase-and-program sequence |
| ERAL before WRAL | Guarantees clean memory array prior to bulk write - prevents partial-data corruption during firmware update |
| Power-on/off protection | Hardware lockout below 1.5 V VCC - blocks inadvertent writes during power ramp-up/down |
| Ready/Busy polling | DO pin provides real-time status without interrupt or additional pins - simplifies host MCU firmware |
| EWEN/EWDS security | Explicit enable/disable commands prevent accidental writes - critical for safety-critical automotive storage |
Applications
| Engine Control Unit (ECU) | Advanced Driver Assistance Systems (ADAS) |
|---|---|
Use Scenario: Storing adaptive fuel trim values, knock sensor learning offsets, and cold-start enrichment tables updated during vehicle operation. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced directly to MCU SPI-compatible GPIO; accessed during idle or diagnostic modes. Use Value: Enables field-updatable calibration without reprogramming main MCU flash - reduces service cost and improves emissions compliance. | Use Scenario: Retaining camera calibration coefficients, radar object detection thresholds, and lane-departure warning sensitivity settings across ignition cycles. IC Role / Device Role / Timing Role: Dedicated parameter store for vision/radar processors; accessed at boot and during dynamic recalibration routines. Use Value: Maintains system accuracy despite thermal drift and mechanical vibration - meets ASIL-B functional safety requirements. |
| Infotainment Head Unit | Body Control Module (BCM) |
Use Scenario: Preserving user preferences (volume level, equalizer settings, Bluetooth pairing IDs) and display brightness profiles across power loss. IC Role / Device Role / Timing Role: Low-power serial EEPROM sharing bus with other peripherals; accessed during UI initialization sequence. Use Value: Delivers instant personalization on power-up - enhances perceived responsiveness and brand loyalty. | Use Scenario: Logging door lock actuation history, window position memory, and interior lighting fade timing parameters for predictive maintenance. IC Role / Device Role / Timing Role: Persistent event logger with deterministic write latency; triggered by CAN message reception or local sensor interrupt. Use Value: Supports OBD-II diagnostics and warranty analytics without adding MCU RAM overhead or flash wear. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 93LC66B-E/ST | 16-bit organization (256 × 16), same VCC/temp range, identical pinout but ORG pin is NC | Requires host software to manage 16-bit word access; incompatible with existing 8-bit firmware interfaces | Select only if system architecture mandates 16-bit data alignment and memory bandwidth optimization |
| AT25DF041A-SH-T | 4 Mbit SPI NOR Flash, quad I/O capable, 2.7–3.6 V only, no built-in erase-before-write | Higher density but requires external erase management; lacks hardware write-protection and auto-ERAL | Choose for firmware image storage where sequential read speed > 10 MHz matters more than byte-level update granularity |
Compared with 93LC66B-E/ST, the 93LC66A-E/ST offers native 8-bit compatibility and simpler firmware integration; versus AT25DF041A-SH-T, it delivers guaranteed atomic byte writes, lower voltage operation, and embedded data protection - essential for safety-critical automotive parameter storage.
Availability
93LC66A-E/ST is available at Aetrix Electronics and suitable for engine control units, ADAS modules, and infotainment systems requiring stable component supply with automotive-grade reliability and traceable sourcing.
Supply support for 93LC66A-E/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 nonvolatile memory solutions, headquartered in Chandler, Arizona.
The 93LC66A-E/ST belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, low-power, and automotive-qualified embedded systems requiring robust, byte-addressable nonvolatile storage.
FAQ
What is the memory organization of the 93LC66A-E/ST?
The 93LC66A-E/ST has a fixed 512 × 8-bit (4 Kbit) organization with no ORG pin - it operates exclusively in x8 mode. Unlike 'C' variants, it does not support runtime switching between 8-bit and 16-bit configurations. This simplifies host interface design and eliminates external logic for ORG control, making it ideal for resource-constrained automotive MCUs.
Does the 93LC66A-E/ST require an external pull-up resistor on the DO pin?
No, the 93LC66A-E/ST does not require an external pull-up on DO. The DO pin actively drives high/low during READ and Ready/Busy polling, and enters High-Z when inactive. However, if DI and DO are shorted (shared bus), a 1–10 kΩ series resistor is mandatory to prevent bus conflict during the dummy zero phase of READ - as specified in DS21795E Section 2.2.
What is the minimum VCC required for reliable operation of the 93LC66A-E/ST?
The 93LC66A-E/ST requires VCC ≥ 2.5 V for full specification compliance across its automotive temperature range (–40°C to +125°C). Its power-on reset (POR) circuit activates at ~1.5 V, disabling all write operations below this threshold to prevent data corruption - a hardware-enforced safeguard critical for automotive brown-out resilience.
Can the 93LC66A-E/ST be used in place of the 93LC66C-E/ST without hardware changes?
No - the 93LC66A-E/ST cannot replace the 93LC66C-E/ST without hardware and firmware revision. The 'C' variant includes an ORG pin to select x8/x16 mode, while the 'A' variant has ORG as NC and is x8-only. Using 93LC66A-E/ST in a design expecting ORG control will result in undefined behavior or communication failure due to missing pin functionality and incompatible instruction timing.
How is data protection implemented during power loss in the 93LC66A-E/ST?
Data protection in the 93LC66A-E/ST is implemented through dual hardware mechanisms: (1) a POR circuit that disables all erase/write operations when VCC drops below ~1.5 V, and (2) default power-up in EWDS (Erase/Write Disable) mode - requiring explicit EWEN command before any programming. These features ensure no partial writes occur during brown-out or cold-start, preserving data integrity per AEC-Q100 stress requirements.
93LC66A-E/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 ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
93LC66A-E/ST FAQ
1.How can I place an order for 93LC66A-E/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 93LC66A-E/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-E/ST reliable?
The price and inventory of 93LC66A-E/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-E/ST is usually 5 days.
3.What payment methods are accepted for 93LC66A-E/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93LC66A-E/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93LC66A-E/ST?
93LC66A-E/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93LC66A-E/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-E/ST?
For technical support, including 93LC66A-E/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93LC66A-E/ST requirements.
6.How does Aetrix verify that 93LC66A-E/ST is sourced from the original manufacturer or authorized distributors?
All 93LC66A-E/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-E/ST meets industry standards.
7.What is the process for return or replacement of 93LC66A-E/ST?
All 93LC66A-E/ST units undergo pre-shipment inspection (PSI). If there is an issue with 93LC66A-E/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-E/ST part is unused and in its original packaging.
Return procedure for 93LC66A-E/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
93LC66A-E/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…
