業界初のSFF/SFP光モジュール向け統合型コントローラ･モニタ
DALLAS, TX—January 22, 2003—Dallas Semiconductor (NASDAQ: MXIM) introduces the DS1854, DS1857, and DS1858 integrated optical controller-monitors. These devices control laser-driver bias and modulation currents, and manage system-monitoring functions required for SFF-8472-compatible optical transceivers. Their high level of integration reduces component count, layout area, and speeds up the design of optical transceivers.
Control functionality is comprised of two 256-position, nonvolatile (NV) variable resistors with temperature indexed look-up tables. To control bias and modulation currents, the module designer determines the desired value for each resistor across temperature in 2°C intervals and stores the data in the on-chip EEPROM look-up tables. The devices then measure temperature, check readings against the EEPROM look-up table, and adjust resistance automatically. This optimizes transceiver operation as the bias and modulation currents adjust automatically with temperature changes.
The DS1854/DS1857/DS1858, provide monitoring through an integrated 12-bit analog-to-digital converter (ADC) and temperature sensor (DS1858/DS1854), monitoring two (DS1854/DS1857) or three (DS1858) external analog signals, as well as VCC and temperature. Programmable alarm trip points for all monitored signals enable the device to alert the system to out-of-tolerance conditions.
The devices also have a flexible EEPROM-addressing architecture, allowing the user to set the memory in different configurations. They can be configured to support 128 bytes of GBIC/SFP MSA memory (at 2-wire address A0h) and 128 bytes of SFF-8472 memory (at 2-wire address A2h). They can also be configured to support 256 bytes of SFF-8472 memory only (at 2-wire address A2h).
The DS1854/DS1857/DS1858 communicate over a 2-wire serial interface. The DS1854 and DS1857 also provide a resistor-disable control input for open-circuiting the two variable resistors. In addition, the DS1857 provides an input for an external temperature sensor and three address inputs that allow up to eight devices on a common serial bus.
The DS1854/DS1857/DS1858 are packaged in a space-saving 4 x 4 BGA (1.0mm pitch) and a 16-pin TSSOP. They operate from a 2.7V to 5.5V supply over a -40°C to +95°C temperature range. Pricing starts at $3.72 (1000-up, FOB USA). An evaluation kit is available.
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