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Microchip Technology AT93C66B-XHM-B
- Part No.:
- AT93C66B-XHM-B
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
AT93C66B-XHM-B.pdf
- Description:
- IC EEPROM 4KBIT 3-WIRE 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:649
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Product details
Overview
AT93C66B-XHM-B 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-B datasheet, AT93C66B-XHM-B pinout, AT93C66B-XHM-B application, or AT93C66B-XHM-B 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 compliance.
Technical Context
The AT93C66B-XHM-B implements a synchronous three-wire serial interface (CS/SK/DI/DO) with rising-edge clocking for instruction, address, and data transfer. Its internal architecture includes an address register, row/column decoders, high-voltage generation circuitry, and power-on reset logic ensuring command rejection during unstable VCC ramp-up.
Memory organization is dynamically selected via the ORG pin: tied to VCC enables 256 × 16 mode; tied to GND enables 512 × 8 mode; unconnected defaults to x16 via internal 10 MΩ pull-up. All operations-including READ, WRITE, ERASE, WRAL, and ERAL-are initiated by 9-bit instruction sequences with start bit and opcode, supporting sequential read and status polling via DO pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 4,096 bits (512 × 8 or 256 × 16) |
| Supply Voltage Range | 1.7V to 5.5V - supports direct interfacing with 1.8V, 2.5V, 3.3V, and 5V logic domains without level shifters |
| Max Clock Frequency | 2 MHz at 4.5–5.5V - enables fast configuration loading in boot-time-critical applications |
| Write Cycle Time | ≤5 ms - deterministic self-timed erase-and-write eliminates need for external timing control |
| Endurance & Retention | 1,000,000 write cycles / 100 years data retention at 55°C - suitable for field-updatable firmware parameters |
| Operating Temperature | −40°C to +85°C - qualified for industrial control, automotive body electronics, and outdoor IoT nodes |
| Interface Protocol | Three-wire serial (CS/SK/DI/DO) - minimal GPIO usage on host MCU, no chip-select decoding logic required |
Pinout & Package
AT93C66B-XHM-B is supplied in an 8-lead SOIC package (3.90 mm body width, 1.27 mm pitch) with standard JEDEC MS-012AC footprint. Pin 1 is marked by a beveled corner or dot; exposed pad is absent in SOIC variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-high enable: device ignores DI and tri-states DO when CS = low; initiates instruction decode on rising edge |
| SK | Serial Data Clock | Rising-edge synchronized interface: latches DI input and clocks DO output on each SK rise; tSKH/tSKL ≥250 ns at 5V |
| DI | Serial Data Input | Receives 9-bit instruction + address + data; requires tDIS/tDIH setup/hold timing relative to SK edge |
| DO | Serial Data Output | Outputs read data or Ready/Busy status (logic '1' = ready, '0' = busy) when CS is asserted post-write/erase |
| GND | Ground Reference | System return path for VCC; must be low-impedance connection to minimize noise coupling into sensitive EEPROM core |
| ORG | Organization Select | Hardware-configured memory map: VCC = 256×16, GND = 512×8, floating = 256×16 (10 MΩ internal pull-up) |
| NC | No Connect | Pin 7 is unconnected internally; must be left floating or tied to GND/VCC per board layout convenience - no electrical effect |
| VCC | Power Supply | Single-supply input: powers all internal logic and charge pump; requires local 100 nF ceramic bypass capacitor near pin |
Key Features
| Feature | Design Value |
|---|---|
| User-selectable memory organization | Hardware-configurable x8 or x16 word width via ORG pin - eliminates software rework when migrating between byte- and word-addressed systems |
| Low-voltage operation down to 1.7V | Enables direct integration into battery-powered or energy-harvesting designs without voltage boosting circuitry |
| Self-timed write cycle | Removes requirement for host MCU to manage write timing or poll status registers - simplifies firmware driver development |
| Industrial temperature rating | Guarantees reliable operation across full −40°C to +85°C range - validated for use in motor drives, PLCs, and outdoor gateways |
| Green packaging | RoHS-compliant, halide-free, lead-free SOIC package - meets global environmental compliance requirements without derating |
Applications
| Industrial Sensor Calibration | Consumer Appliance Configuration |
|---|---|
Use Scenario: Storing factory-trimmed sensor offset/gain coefficients and linearization tables in pressure/temperature transmitters. IC Role / Device Role / Timing Role: Nonvolatile parameter store accessed during power-up initialization; read-only during normal operation. Use Value: Enables plug-and-play sensor replacement without manual recalibration; retains values through 10+ year product lifecycle. | Use Scenario: Holding user preferences (e.g., cooking time, temperature presets, display brightness) in microwave ovens and washing machines. IC Role / Device Role / Timing Role: Low-power configuration memory updated infrequently (<100 writes/year) during menu navigation or button presses. Use Value: Survives frequent power cycling and brownouts; operates reliably at 3.3V from appliance SMPS rail. |
| Automotive Body Control Module | Medical Diagnostic Equipment |
Use Scenario: Saving seat/mirror position memory, door lock settings, and lighting profiles in 12V vehicle subsystems. IC Role / Device Role / Timing Role: EEPROM interface driven by 8-bit/16-bit automotive MCU over dedicated three-wire bus; accessed during ignition-on sequence. Use Value: Qualified for −40°C to +85°C ambient; withstands load-dump transients via robust internal ESD structure. | Use Scenario: Storing calibration constants, usage logs, and safety-critical configuration flags in portable ultrasound and glucose meters. IC Role / Device Role / Timing Role: Secure nonvolatile storage for FDA-regulated data; write-protected via EWDS after initial commissioning. Use Value: 100-year data retention ensures integrity over equipment lifetime; 1M endurance supports periodic firmware updates. |
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 cycle, same 1.7–5.5V range | Requires separate SPI peripheral and CS line; incompatible pinout and protocol stack | Select when host MCU has dedicated SPI hardware and higher throughput (>2×) is needed |
| BR24G64FJ-3GE2 | 4-Kbit I²C interface (2-wire), 1 MHz max clock, 5 ms write cycle, 1.7–5.5V, built-in write protection | Uses SDA/SCL pins; requires I²C address arbitration; lacks ORG-pin organization flexibility | Prefer for systems already using I²C peripherals and needing multi-device bus sharing |
Compared with M95640-DRMN6TP/K and BR24G64FJ-3GE2, the AT93C66B-XHM-B offers unique hardware-selectable x8/x16 organization and minimal three-wire footprint-ideal for GPIO-constrained microcontrollers where SPI/I²C peripherals are unavailable or occupied.
Availability
AT93C66B-XHM-B is available at Aetrix Electronics and suitable for industrial sensor calibration, consumer appliance configuration, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for AT93C66B-XHM-B 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-B belongs to Microchip's legacy AT93CxxB serial EEPROM product line, designed specifically for cost-sensitive, space-constrained embedded systems requiring robust nonvolatile storage with minimal interface overhead.
FAQ
What is the memory organization of AT93C66B-XHM-B and how is it configured?
The AT93C66B-XHM-B provides 4-Kbit capacity as either 512 × 8-bit words or 256 × 16-bit words. Configuration is controlled by the ORG pin: tying ORG to VCC selects x16 mode; tying ORG to GND selects x8 mode; leaving ORG floating defaults to x16 via internal 10 MΩ pull-up. This hardware-selectable organization avoids firmware changes when adapting to different host data bus widths.
Does AT93C66B-XHM-B require external components for reliable operation?
Yes - AT93C66B-XHM-B requires a 100 nF ceramic bypass capacitor placed as close as possible to the VCC and GND pins to suppress supply noise during write cycles. No pull-up resistors are needed on CS, SK, or DI, as the device uses active-drive inputs. The DO pin is open-drain compatible but functions as push-pull in standard operation.
What is the maximum clock frequency supported by AT93C66B-XHM-B at 3.3V supply?
At 3.3V supply, the AT93C66B-XHM-B supports a maximum clock frequency of 1 MHz, as specified in its AC characteristics table. This is lower than the 2 MHz maximum achievable at 4.5–5.5V, due to internal timing constraints of the charge pump and logic propagation delays under reduced voltage.
How does the AT93C66B-XHM-B indicate write completion during programming?
The AT93C66B-XHM-B outputs Ready/Busy status on the DO pin: after initiating a WRITE or ERASE command, if CS is brought high following a minimum tCS low time, DO will output logic '0' while busy and logic '1' when complete. This allows host firmware to poll status without fixed delay loops, improving system responsiveness and power efficiency.
Is AT93C66B-XHM-B pin-compatible with earlier AT93C66A variants?
No - AT93C66B-XHM-B is not pin-compatible with AT93C66A. While both share identical pinout and package, the B-version introduces enhanced ESD protection, tighter DC/AC specifications, and improved data retention. Migration requires validation of timing margins and voltage thresholds but no PCB redesign.
AT93C66B-XHM-B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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-B FAQ
1.How can I place an order for AT93C66B-XHM-B through Aetrix?
Please submit a Request for Quotation (RFQ) for AT93C66B-XHM-B 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-B reliable?
The price and inventory of AT93C66B-XHM-B 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-B is usually 5 days.
3.What payment methods are accepted for AT93C66B-XHM-B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT93C66B-XHM-B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT93C66B-XHM-B?
AT93C66B-XHM-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT93C66B-XHM-B 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-B?
For technical support, including AT93C66B-XHM-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT93C66B-XHM-B requirements.
6.How does Aetrix verify that AT93C66B-XHM-B is sourced from the original manufacturer or authorized distributors?
All AT93C66B-XHM-B 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-B meets industry standards.
7.What is the process for return or replacement of AT93C66B-XHM-B?
All AT93C66B-XHM-B units undergo pre-shipment inspection (PSI). If there is an issue with AT93C66B-XHM-B, 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-B part is unused and in its original packaging.
Return procedure for AT93C66B-XHM-B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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