Microchip Technology 11LC161-I/MS

Overview

11LC161-I/MS from Microchip Technology Inc. is a 16 Kbit (2,048 × 8) serial EEPROM using the UNI/O® single I/O bus interface. It operates from 2.5V to 5.5V, delivers 1 mA typical active current and 1 µA max standby current over –40°C to +85°C, and supports 100 kbps bit rate with Manchester-encoded SCIO communication. It is used in space-constrained industrial control modules for nonvolatile parameter storage.

For engineers reviewing the 11LC161-I/MS datasheet, 11LC161-I/MS pinout, 11LC161-I/MS application, or 11LC161-I/MS equivalent, key selection considerations include its 3-lead MSOP package, I²C-free single-pin UNI/O® interface, 16-byte page write buffer, block write protection options, and automotive-grade temperature support up to +125°C on E-temp variants.

Technical Context

The 11LC161-I/MS implements a Manchester-encoded, master-controlled UNI/O® bus protocol with SCIO as the sole bidirectional signal line. Its internal architecture includes a 16-byte page latch, STATUS register with WIP/WEL/BP bits, and re-synchronization circuitry tolerant to ±0.50% frequency drift per byte and ±0.06 UI input edge jitter.

It features Schmitt-trigger SCIO inputs for noise immunity, slope-controlled output drivers to suppress ground bounce, and built-in power-on/off write protection. The device uses charge-pump-based high-voltage generation for EEPROM programming and supports self-timed write cycles up to 10 ms per page.

Key Specifications

Pinout & Package

11LC161-I/MS is housed in an 8-lead MSOP (MS) package with exposed pad (non-electrical), measuring 3.0 mm × 3.0 mm × 1.1 mm. Pin 1 is SCIO, Pin 2 is VSS, Pin 3 is VCC; Pins 4–8 are No Connect (NC).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Compared with 11AA161-I/MS, the 11LC161-I/MS supports higher minimum VCC (2.5V vs. 1.8V) but extends temperature capability to +125°C in E-temp versions; versus 24LC16B-I/MS, it reduces GPIO usage by 1 pin and eliminates clock-line routing, at the cost of lower maximum data rate.

Availability

11LC161-I/MS is available at Aetrix Electronics and suitable for industrial control, medical instrumentation, and automotive body electronics requiring stable component supply, long-life data retention, and compact packaging.

Supply support for 11LC161-I/MS 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory products, with emphasis on reliability, low-power design, and embedded control solutions.

The 11LC161-I/MS belongs to Microchip's UNI/O® Serial EEPROM family, designed specifically for space- and pin-constrained applications where traditional 2-wire or SPI interfaces are impractical - targeting industrial, medical, and automotive subsystems needing robust, low-overhead nonvolatile storage.

FAQ

What is the UNI/O® interface used by the 11LC161-I/MS, and how does it differ from I²C?

The 11LC161-I/MS uses Microchip's patented UNI/O® bus - a single-wire, Manchester-encoded serial interface that combines clock and data on the SCIO pin. Unlike I²C, it requires no separate clock line (SCL), no arbitration, and no pull-up resistors on the data line beyond one external pull-up. This reduces PCB routing complexity and GPIO usage compared to I²C-based EEPROMs like the 24LC16B-I/MS, while maintaining deterministic timing through master-controlled bit periods.

Does the 11LC161-I/MS support write protection, and how is it configured?

Yes, the 11LC161-I/MS supports hardware-configurable block write protection via two nonvolatile BP0/BP1 bits in its STATUS register. These bits - set using the WRSR instruction - allow locking 0%, 25%, 50%, or 100% of the memory array. Protection is enforced at the hardware level during WRITE commands, preventing accidental overwrites of critical calibration or firmware data without first clearing the protection bits via WRSR.

What is the maximum write speed and page buffer size of the 11LC161-I/MS?

The 11LC161-I/MS supports a maximum bit rate of 100 kbps (equivalent to 100 kHz clock frequency), with a fixed 16-byte page buffer. Up to 16 bytes can be loaded into the buffer before initiating the internal write cycle. Write cycle time is up to 10 ms for full-page writes. Because physical pages are aligned to 16-byte boundaries (e.g., 0x00–0x0F), crossing a boundary causes wraparound - so firmware must validate address alignment before multi-byte writes.

How does the 11LC161-I/MS handle power loss during a write operation?

The 11LC161-I/MS includes built-in power-loss write protection: the write enable latch resets on power-up, and the device incorporates power-on/off detection circuitry that inhibits writes until VCC stabilizes. Additionally, the STATUS register's WIP bit allows host firmware to poll write progress, avoiding premature power removal. Combined with auto-erase-before-write and 1,000,000-cycle endurance, this ensures data integrity even in brown-out conditions common in industrial power supplies.

Is the 11LC161-I/MS pin-compatible with other devices in the 11XX family?

Yes - all 11XX-family devices in the 8-lead MSOP (MS) package, including 11LC161-I/MS, 11AA161-I/MS, and 11LC080-I/MS, share identical pinouts: SCIO on Pin 1, VSS on Pin 2, VCC on Pin 3, and NC on Pins 4–8. This allows drop-in replacement within the same density and voltage range, provided firmware accounts for differences in device address (0xA1 for 11LC161 vs. 0xA0 for 11LC160) and VCC minima.