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Microchip Technology AT93C66B-XHM-T
- Part No.:
- AT93C66B-XHM-T
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
AT93C66B-XHM-T.pdf
- Description:
- IC EEPROM 4KBIT 3-WIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:19,581
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Product details
Overview
AT93C66B-XHM-T from Microchip Technology is a 4-Kbit three-wire serial EEPROM organized as 512 × 8 or 256 × 16, operating from 1.7V to 5.5V with industrial temperature range (−40°C to +85°C), 2 MHz max clock rate at 5V, and self-timed write cycle ≤5 ms. It serves as nonvolatile configuration storage in microcontroller-based embedded systems requiring low-voltage operation and space-constrained PCB layouts.
For engineers reviewing the AT93C66B-XHM-T datasheet, AT93C66B-XHM-T pinout, AT93C66B-XHM-T application, or AT93C66B-XHM-T equivalent, key selection considerations include voltage compatibility (1.7–5.5V), ORG-pin-selectable memory organization (x8/x16), industrial-grade reliability (1M write cycles, 100-year data retention), and SOIC-8 package footprint compatibility with legacy designs.
Technical Context
The AT93C66B-XHM-T implements a synchronous three-wire serial interface (CS/SK/DI/DO) with no separate erase step required before write. Its internal organization is dynamically selected via the ORG pin: tied to VCC for 256 × 16 mode, to GND for 512 × 8 mode, or left floating (10 MΩ pull-up) for default x16 configuration.
It features a Power-on Reset (POR) circuit with 1.5 V threshold and requires ≥100 µs stable VCC before first command. Write operations are enabled only after EWEN instruction and disabled by EWDS or power cycle, ensuring data integrity during brown-out or reset events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4 Kbit (512 × 8 or 256 × 16), enabling compact firmware parameter or calibration storage |
| Supply Voltage Range | 1.7 V to 5.5 V - supports direct interfacing with 1.8 V, 3.3 V, and 5 V logic domains without level shifters |
| Max Clock Frequency | 2 MHz at 4.5–5.5 V - enables fast read/write throughput in time-critical boot or configuration sequences |
| Write Cycle Time | ≤5 ms maximum - ensures predictable timing budget for host MCU firmware during nonvolatile updates |
| Endurance & Retention | 1,000,000 write cycles / 100 years data retention at 55°C - suitable for field-upgradable industrial control systems |
| Operating Temperature | −40°C to +85°C - qualified for deployment in automotive under-hood, industrial PLC, and outdoor IoT nodes |
| Interface Protocol | Three-wire serial (CS/SK/DI/DO) - reduces GPIO count vs. SPI/I²C, ideal for pin-limited MCUs |
Pinout & Package
AT93C66B-XHM-T is housed in an 8-lead SOIC package (3.9 mm body width, 1.27 mm pitch), RoHS-compliant and green (lead-free/halide-free). Pin 1 is marked with a notch or dot; exposed pad is not present in SOIC variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-high enable: device responds only when CS = high; DO enters high-Z when CS = low |
| SK | Serial Data Clock | Rising-edge synchronized I/O: latches DI on rising SK, outputs DO on rising SK |
| DI | Serial Data Input | Receives instruction opcodes (READ/EWEN/ERASE/WRITE), addresses, and data bits |
| DO | Serial Data Output | Outputs read data or Ready/Busy status (logic '1' = ready, '0' = busy during write/erase) |
| GND | Ground Reference | System ground return path; must be low-impedance connection for noise immunity |
| ORG | Organization Select | Configures memory map: VCC = 256×16, GND = 512×8, floating = 256×16 (10 MΩ pull-up) |
| NC | No Connect | Pin 7 is unconnected internally; must be left floating or tied to GND/VCC per layout constraints |
| VCC | Power Supply | Single supply input (1.7–5.5 V); decoupling capacitor (0.1 µF ceramic) required near pin |
Key Features
| Feature | Design Value |
|---|---|
| User-selectable x8/x16 organization | Enables flexible byte- or word-oriented access without external address decoding logic |
| Self-timed write cycle | Eliminates need for host MCU to poll status or manage variable write timing across voltage/temp |
| Sequential read capability | Reduces transaction overhead: continuous data stream with auto-incremented address pointer |
| Industrial temperature rating | Validated operation from −40°C to +85°C ensures reliability in harsh environments |
| Green packaging | RoHS-compliant, lead-free, halide-free SOIC meets global environmental compliance requirements |
Applications
| Motor Control Firmware Storage | Smart Sensor Calibration Data |
|---|---|
Use Scenario: Storing motor commutation tables, PID coefficients, and fault logs in BLDC driver modules. IC Role / Device Role / Timing Role: Nonvolatile configuration memory accessed during MCU boot and runtime reconfiguration. Use Value: Enables field-upgradable motor parameters without redesigning PCB or replacing MCU flash. | Use Scenario: Retaining factory-trimmed offset/gain values and temperature compensation curves for MEMS accelerometers. IC Role / Device Role / Timing Role: Dedicated calibration storage decoupled from main MCU flash, updated only during production test. Use Value: Maintains sensor accuracy over lifetime and temperature without consuming MCU program memory. |
| Industrial HMI Display Settings | Medical Device Configuration Backup |
Use Scenario: Saving user preferences (brightness, language, alarm thresholds) in panel-mounted HMIs for factory automation. IC Role / Device Role / Timing Role: Low-power, infrequent-write storage accessible via minimal GPIOs on display controller SoC. Use Value: Survives power loss and retains settings across 10+ years of operation with no battery backup. | Use Scenario: Backing up critical therapy parameters (dose limits, safety interlocks) in portable infusion pumps. IC Role / Device Role / Timing Role: Fail-safe configuration store verified at power-on before treatment initiation. Use Value: Meets IEC 62304 Class C software requirements for persistent, tamper-resistant data retention. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| M95640-DRMN6TP/K | 4-Kbit SPI interface (4-wire), 20 MHz max clock, 5 ms write time, same 1.7–5.5 V range | Requires dedicated SPI peripheral; higher speed but needs extra CS line vs. AT93C66B-XHM-T's 3-wire simplicity | Select when system already uses SPI peripherals and demands faster sequential reads |
| 24LC64T-I/SN | 64-Kbit I²C interface, 400 kHz standard mode, 5 ms write time, 2.5–5.5 V range | Wider memory capacity but narrower voltage range; requires I²C pull-ups and ACK handling | Select when larger storage is needed and I²C bus is available; avoid if 1.7–2.4 V operation is required |
Compared with M95640-DRMN6TP/K and 24LC64T-I/SN, the AT93C66B-XHM-T offers lowest pin count (3-wire), widest voltage support (1.7 V), and simplest MCU GPIO usage-ideal for resource-constrained designs where SPI/I²C peripherals are unavailable or oversubscribed.
Availability
AT93C66B-XHM-T is available at Aetrix Electronics and suitable for industrial motor drives, smart sensor nodes, medical device configuration backup, and HMI display settings requiring stable component supply across long product lifecycles.
Supply support for AT93C66B-XHM-T 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 is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with ISO 9001-certified manufacturing and global distribution.
The AT93C66B-XHM-T belongs to Microchip's legacy serial EEPROM product line, designed specifically for cost-sensitive, space-constrained embedded systems needing reliable nonvolatile storage with minimal interface complexity.
FAQ
What is the memory organization of AT93C66B-XHM-T and how is it configured?
The AT93C66B-XHM-T provides 4-Kbit storage in either 512 × 8 or 256 × 16 configuration. The ORG pin determines organization: tie to VCC for 256 × 16 mode, to GND for 512 × 8 mode, or leave floating (internal 10 MΩ pull-up defaults to x16). This selection is static and must be set at power-on; the AT93C66B-XHM-T does not support dynamic reconfiguration during operation.
Does AT93C66B-XHM-T require an external erase command before writing?
No, the AT93C66B-XHM-T does not require a separate erase command before write. Its write cycle is self-timed and automatically erases the target location prior to programming. However, the Erase (ERASE) and Erase All (ERAL) commands are available for selective or full-array erasure, with ERAL valid only at VCC ≥ 4.5 V per datasheet DS20006260A.
What is the maximum clock frequency supported by AT93C66B-XHM-T at 3.3 V operation?
At 3.3 V (within 2.5–5.5 V range), the AT93C66B-XHM-T supports a maximum clock frequency of 1 MHz, as specified in Table 4-3 of the datasheet. This is lower than its 2 MHz rating at 4.5–5.5 V, reflecting reduced timing margins at intermediate supply voltages.
How does AT93C66B-XHM-T indicate write completion during a programming cycle?
The AT93C66B-XHM-T outputs Ready/Busy status on the DO pin when CS is brought high after being low for ≥tCS (min 250 ns at 2.5–5.5 V). A logic '1' on DO indicates completion and readiness for next command; logic '0' indicates ongoing write. This eliminates need for fixed delay polling and adapts to actual write time variation across voltage/temperature.
Is AT93C66B-XHM-T compatible with 1.8 V microcontroller I/O interfaces?
Yes, AT93C66B-XHM-T operates down to 1.7 V and supports 1.8 V logic levels: VIH2 = 0.7 × VCC (≥1.26 V at 1.8 V) and VIL2 = 0.3 × VCC (≤0.54 V), meeting standard 1.8 V CMOS thresholds. Its input leakage (<3 µA) and output drive (VOH2 = VCC − 0.2 V) ensure robust interoperability with 1.8 V MCUs without level shifting.
AT93C66B-XHM-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 4Kbit
- Memory Organization:
- 512 x 8, 256 x 16
- Memory Interface:
- 3-Wire Serial
- Clock Frequency:
- 2 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 1.7V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
AT93C66B-XHM-T FAQ
1.How can I place an order for AT93C66B-XHM-T through Aetrix?
Please submit a Request for Quotation (RFQ) for AT93C66B-XHM-T 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 AT93C66B-XHM-T reliable?
The price and inventory of AT93C66B-XHM-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT93C66B-XHM-T is usually 5 days.
3.What payment methods are accepted for AT93C66B-XHM-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT93C66B-XHM-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT93C66B-XHM-T?
AT93C66B-XHM-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT93C66B-XHM-T 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 AT93C66B-XHM-T?
For technical support, including AT93C66B-XHM-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT93C66B-XHM-T requirements.
6.How does Aetrix verify that AT93C66B-XHM-T is sourced from the original manufacturer or authorized distributors?
All AT93C66B-XHM-T 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 AT93C66B-XHM-T meets industry standards.
7.What is the process for return or replacement of AT93C66B-XHM-T?
All AT93C66B-XHM-T units undergo pre-shipment inspection (PSI). If there is an issue with AT93C66B-XHM-T, 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 AT93C66B-XHM-T part is unused and in its original packaging.
Return procedure for AT93C66B-XHM-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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