The X9521 is a chip with features of a digitally controlled potentiometer (DCP), EEPROM memory, and fiber optic module control. It has high resolution and non-volatile characteristics, and can be controlled through a 2-wire serial interface. The X9521 can be used to control the bias and modulation currents of the laser diode in a fiber optic module, and can store module definition data.
The X9521 combines two digitally controlled potentiometers (DCPs) and a 2 kbit EEPROM in a single 20‑lead TSSOP package. It operates from a single supply of 2.7 V to 5.5 V and is hot‑pluggable, making it suitable for Gigabit Interface Converter (GBIC) laser modules.
The document provides detailed pin configuration, serial 2‑wire interface timing, internal addressing, write‑protect features, and operation of both volatile and non‑volatile DCP writes. Appendices include tap‑to‑data‑byte translation algorithms and mechanical drawing dimensions.
| Supply Voltage Range | 2.7 V to 5.5 V |
|---|---|
| Package Type | 20‑lead TSSOP |
| Operating Temperature Range | -40 °C to +85 °C |
| EEPROM Memory Size | 2 kbit |
| DCP Tap Count (DCP1) | 100 taps |
| DCP Tap Count (DCP2) | 256 taps |
| Hot‑Pluggable | Yes |
| Write Protect Pin (WP) | TTL‑level input, active HIGH |
The X9521 operates from 2.7 V up to 5.5 V.
It is supplied in a 20‑lead TSSOP package.
The WP pin is a TTL‑level input that enables write protection when held HIGH, preventing all non‑volatile write operations.
The device contains a 2 kbit EEPROM.