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Microchip Technology 93C66B-E/P
- Part No.:
- 93C66B-E/P
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
93C66B-E/P.pdf
- Description:
- IC EEPROM 4KBIT MICROWIRE 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,370
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Product details
Overview
93C66B-E/P from Microchip Technology Inc. is a 4 Kbit (256 x 16-bit) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, 4.5–5.5 V supply range, and industrial-temperature operation (–40°C to +85°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 - used in embedded system configuration storage and calibration data retention.
For engineers reviewing the 93C66B-E/P datasheet, 93C66B-E/P pinout, 93C66B-E/P application, or 93C66B-E/P equivalent, key selection criteria include its fixed 16-bit organization (no ORG pin), 2 ms program cycle time, 1 million endurance cycles, 200-year data retention, and compatibility with legacy Microwire controllers in space-constrained industrial modules.
Technical Context
The 93C66B-E/P implements a synchronous serial interface with CS, CLK, and DI/DO pins, requiring no external clock source beyond the host controller's CLK signal. Its instruction set includes READ, WRITE, ERASE, ERAL, WRAL, EWEN, and EWDS - all executed via 12-clock-cycle sequences for x16 mode.
Unlike C-variant parts, the 93C66B lacks an ORG pin and is permanently configured for 16-bit word access. Erase/write initiation uses the rising edge of CLK on the final data bit, not the falling edge of CS - a timing distinction critical for timing budgeting in real-time firmware.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 4 Kbit (256 words × 16 bits) - supports compact firmware parameter tables without byte-level addressing overhead |
| VCC range | 4.5 V to 5.5 V - compatible with standard 5 V logic rails; POR threshold at 3.8 V prevents spurious writes during brown-out |
| Endurance | 1,000,000 erase/write cycles - enables daily field calibration updates for >2,700 years at one cycle per day |
| Data retention | 200 years at 25°C - ensures long-term reliability in unattended infrastructure equipment |
| Write cycle time | 2 ms typical - allows deterministic timeout handling in interrupt-driven drivers without polling delays |
| Max clock frequency | 3 MHz at VCC ≥ 4.5 V - supports high-throughput configuration loading in microcontroller boot sequences |
| Interface | Microwire-compatible 3-wire serial (CS/CLK/DI/DO) - reuses existing GPIO bit-banged drivers; no SPI mode bits required |
Pinout & Package
Package: 8-lead PDIP (P), lead-free Matte Tin finish, through-hole mounting. Pin 1 identified by notch or dot; pin 1 ID confirmed per DS21795E-page 18.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CS) | Chip Select | Active-high enable; must be held low ≥250 ns between instructions; deselects device into standby but completes ongoing write |
| 2 (CLK) | Serial Clock | Rising-edge synchronized I/O; stops/resumes freely; rising edge on final data bit triggers self-timed write on 93C66B |
| 3 (DI) | Data Input | Accepts Start bit, opcode, address, and 16-bit data; tied high with pull-up for Start detection |
| 4 (DO) | Data Output / Status | Outputs 16-bit read data or Ready/Busy (low = busy); enters High-Z when CS low or after status read |
| 5 (VSS) | Ground | Reference return path; decoupling capacitor required within 10 mm of VCC pin |
| 6 (NC) | No Connect | Internally unconnected; must remain floating or tied to VSS per design rules - no routing or loading allowed |
| 7 (NC) | No Connect | Same as Pin 6; dual NC pins confirm absence of ORG function in 'B' variant |
| 8 (VCC) | Power Supply | 4.5–5.5 V input; internal POR circuit blocks writes below 3.8 V; requires 0.1 µF ceramic bypass |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 16-bit organization | Eliminates ORG pin routing and level-setting logic; simplifies PCB layout and firmware address mapping for word-aligned data |
| Self-timed erase/write | Removes need for external timing control or watchdog resets; firmware only waits for DO=high or polls status |
| Automatic ERAL before WRAL | Guarantees full-array readiness prior to bulk write - prevents partial-write corruption in power-fail scenarios |
| EWEN/EWDS security protocol | Requires explicit enable before each write/erase; prevents accidental overwrites during debug or noise events |
| Ready/Busy status on DO | Enables non-blocking polling or interrupt-driven completion detection without additional GPIO or status registers |
Applications
| Industrial Sensor Calibration | Legacy MCU Configuration Storage |
|---|---|
Use Scenario: Storing temperature-compensation coefficients and sensor offset values in factory-calibrated pressure transmitters operating continuously for 15+ years. IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed during power-up initialization and periodic recalibration routines. Use Value: 200-year data retention and 1M endurance ensure calibration integrity across product lifetime without field replacement. | Use Scenario: Holding bootloader configuration flags, UART baud dividers, and I²C slave addresses in 8-bit microcontrollers lacking internal EEPROM. IC Role / Device Role / Timing Role: Serial configuration memory mapped via bit-banged Microwire interface during system reset sequence. Use Value: Fixed 16-bit word size aligns with common MCU register widths, reducing firmware bit-manipulation overhead. |
| Automotive Subsystem Parameter Backup | Medical Device Usage Logs |
Use Scenario: Recording fault counters and last-known operational states in HVAC control modules subjected to thermal cycling from –40°C to +85°C. IC Role / Device Role / Timing Role: Fail-safe backup memory updated only on shutdown or error condition - not during active control loops. Use Value: Industrial temp grade and 4.5–5.5 V operation match automotive 5 V supply rails and extended ambient requirements. | Use Scenario: Logging patient session timestamps and therapy settings in portable infusion pumps requiring FDA-compliant audit trails. IC Role / Device Role / Timing Role: Tamper-resistant event log storage with write-protection enforced by EWEN/EWDS command sequence. Use Value: Power-on data protection and automatic ERAL-before-WRAL prevent log corruption during unexpected power loss. |
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/P | Wider VCC range (2.5–5.5 V); same 256×16 organization and pinout; supports extended temperature (–40°C to +125°C) with E-grade marking | Required for designs needing 2.5 V operation or automotive qualification (AEC-Q100) | Select 93LC66B-I/P if supply voltage may dip below 4.5 V or if extended temperature range is mandatory |
| AT25040B-MAU-2.7 | SPI interface (4-wire), 512×8 organization, 2.7–5.5 V, 10 MHz max clock; no Ready/Busy pin - relies on WIP flag polling | Used where SPI-native MCUs eliminate bit-banging; incompatible timing and command structure vs. Microwire | Choose AT25040B-MAU-2.7 only when migrating to SPI architecture and accepting different firmware driver layer |
Compared with 93LC66B-I/P, the 93C66B-E/P offers tighter VCC tolerance and lower cost for 5 V-only systems; versus AT25040B-MAU-2.7, it retains Microwire compatibility and hardware-ready/busy signaling - critical for deterministic real-time response.
Availability
93C66B-E/P is available at Aetrix Electronics and suitable for industrial sensor calibration, legacy MCU configuration storage, and medical device usage logs requiring stable component supply across multi-year production cycles.
Supply support for 93C66B-E/P 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 93C66B-E/P belongs to Microchip's legacy 93XX serial EEPROM family, designed specifically for cost-sensitive, space-constrained embedded systems requiring reliable nonvolatile storage with minimal external components and legacy interface support.
FAQ
What is the memory organization of the 93C66B-E/P?
The 93C66B-E/P has a fixed 256 × 16-bit organization - meaning it stores 256 words of 16 bits each, totaling 4 Kbit. Unlike 'C' variants, it has no ORG pin and does not support runtime switching between 8-bit and 16-bit modes. This configuration is hardwired and verified in the Device Selection Table of DS21795E.
Does the 93C66B-E/P require an external pull-up resistor on the DO pin?
Yes, the 93C66B-E/P requires an external pull-up resistor on the DO pin when used in shared-bus configurations or when interfacing with open-drain logic. The DO pin operates in three states: driven high/low during read, actively driven low for Ready/Busy, and High-Z otherwise. A 4.7 kΩ pull-up to VCC ensures valid logic levels during status polling and prevents floating inputs.
How does the 93C66B-E/P handle power loss during a write operation?
The 93C66B-E/P incorporates power-on/off data protection circuitry that inhibits all operations when VCC drops below 3.8 V. Combined with its self-timed write architecture and automatic ERAL-before-WRAL, this ensures that partial writes cannot corrupt memory contents. If power fails mid-cycle, the device resumes from a known-valid state on next power-up - no external capacitors or backup supplies are needed.
Can the 93C66B-E/P be used with modern microcontrollers that lack native Microwire support?
Yes, the 93C66B-E/P can be interfaced with any microcontroller using GPIO bit-banging, as its Microwire protocol is fully synchronous and timing-deterministic. The datasheet specifies exact setup/hold times (e.g., TDIS = 50 ns min at 4.5 V), enabling robust software implementation on ARM Cortex-M, PIC, or RISC-V devices without dedicated peripheral hardware.
What is the purpose of the two NC pins on the 93C66B-E/P PDIP package?
Pins 6 and 7 on the 93C66B-E/P PDIP package are No Connect (NC) terminals - internally unconnected and electrically isolated. They exist to maintain pin compatibility across the 93XX66 family (e.g., matching pin count with ORG-equipped 'C' variants) and must remain unconnected in layout. Routing traces to or placing vias on these pins violates Microchip's design guidelines and may cause assembly or test failures.
93C66B-E/P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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:
- 2ms
- Access Time:
- -
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
93C66B-E/P FAQ
1.How can I place an order for 93C66B-E/P through Aetrix?
Please submit a Request for Quotation (RFQ) for 93C66B-E/P 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 93C66B-E/P reliable?
The price and inventory of 93C66B-E/P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 93C66B-E/P is usually 5 days.
3.What payment methods are accepted for 93C66B-E/P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 93C66B-E/P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 93C66B-E/P?
93C66B-E/P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 93C66B-E/P 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 93C66B-E/P?
For technical support, including 93C66B-E/P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 93C66B-E/P requirements.
6.How does Aetrix verify that 93C66B-E/P is sourced from the original manufacturer or authorized distributors?
All 93C66B-E/P 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 93C66B-E/P meets industry standards.
7.What is the process for return or replacement of 93C66B-E/P?
All 93C66B-E/P units undergo pre-shipment inspection (PSI). If there is an issue with 93C66B-E/P, 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 93C66B-E/P part is unused and in its original packaging.
Return procedure for 93C66B-E/P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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