Unveiling the Key Data Guardian of Switches: Technical Advantages and Selection Guide for 256 Kbit Asynchronous NVRAM

In modern switch architectures, non-volatile random-access memory (NVRAM) has become the critical component for storing configuration parameters, routing tables, and runtime logs thanks to its high-speed read/write capability and data persistence after power loss. Unlike conventional Flash, which must be erased in large blocks, NVRAM supports byte-level programming—data can be written directly without a prior erase cycle—dramatically accelerating configuration reconstruction when power is restored. Its micro-second-class write latency satisfies the real-time logging demands of network equipment and eliminates the risk of service interruption caused by data loss.

A 256-Kbit asynchronous NVRAM acts as both a buffer and guardian for mission-critical data inside the switch. This density is sufficient to hold the entire boot configuration, a copy of the routing table, and the device’s operational-state log, ensuring that the system can return to the last stable state immediately after an unexpected power failure. Key advantages include:

- An asynchronous interface that needs no clock-synchronization signal, simplifying interconnection to the switch ASIC

- Nanosecond-class write speed that enables real-time recording of network-traffic statistics

- 10¹² erase/write cycles that guarantee maintenance-free operation for a full decade of service

For example, during a spanning-tree reconvergence the NVRAM can instantaneously save topology-change records, preventing network oscillations that would otherwise result from data loss.

MCLogic’s MC90NP256K33T44SCH-A is a 256-Kbit asynchronous NVRAM built on an advanced CMOS process and offered in a 44-pin TSOP-II package operating from 3.3 V ±10 %. Through an innovative architecture the device achieves breakthrough performance: an on-chip charge-pump eliminates the need for an external battery, asynchronous read/write cycles are completed in 45 ns, and standby current is reduced to 100 µA. Compared with competing devices its specifications are industry-leading:

- Access time: 45 ns (typical competitor value 70 ns)

- Data retention: 20 years in self-powered mode (battery-free)

- Operating temperature: –40 °C to +85 °C (industrial grade)

- Package footprint: 10.16 mm × 18.41 mm (30 % smaller than SOP)

An integrated power-monitor circuit automatically switches the part into data-protection mode when a voltage sag is detected, guaranteeing the integrity of the last 128 bytes written. In switch applications the device connects directly to the main CPU through an asynchronous bus—no interface translation logic is required—providing real-time backup of configuration data.

As MCLogic’s authorized distributor, MANDU offers signal-integrity simulation, timing analysis, free samples, and failure-analysis services to help customers achieve NEBS compliance.

For switch manufacturers, MCLogic’s asynchronous NVRAM delivers hardware-level data protection, long lifetime, and high reliability in a single-chip solution that significantly reduces external BOM count while meeting harsh deployment environments with its industrial temperature rating. Backed by MANDU’s local technical support, customers can complete circuit optimization and troubleshooting quickly, shortening time-to-market.

About Mandu Technology

Shenzhen Mandu Technology Co., Ltd. has steadfastly centered its operations on the distribution of high-performance, high-quality, and highly reliable integrated circuit products. Its portfolio encompasses memory chips, differential crystal oscillators, and MCU microcontrollers, while progressively integrating analog signal chain products. The company prides itself on delivering comprehensive and cost-effective solutions to its customers. Its products find applications across a broad spectrum of industries, including but not limited to network communication, industrial control, robotics, medical equipment, personal health, and numerous other fields.

Business: sales@manduic.com