ADSL Line Driver Sets Size And Power Dissipation Records

Significant reductions in power dissipation and real estate requirements are promised to designers who incorporate the THS6032 line driver chip in their new central office asymmetrical digital subscriber line (ADSL) and digital subscriber loop access multiplexer (DSLAM) products. This full-rate ADSL- and G.lite-capable line driver is said to be the first to employ a Class G rather than Class AB amplifier architecture. By using four power supplies rather than the Class AB amplifier’s two, the Class G architecture can bring about a lowering of power dissipation. The four supplies are typically rated at ±5V and ±15V, with the THS6032 chip reducing power consumption to only 1.3W on a full-rate 25 ohm ADSL line by using the lower voltage supply except when the higher is needed- the switching between supplies is done automatically. Furthermore, the THS6032 keeps total harmonic distortion low even when the driver is switching between supplies. The new ADSL line driver is capable of reducing power dissipation even further by shifting into a low impedance shutdown mode, with the mode also providing the back termination required to receive incoming signals while the device is shut down- this allows the reception of incoming communications, including 911 emergency calls, while the chip is in its shutdown mode. The THS6032 is also part of the firm’s DSP-based TNETD4000C chipset that supports up to four ADSL lines. The chip currently comes in the firm’s 20-pin SOIC PowerPAD package that offers enhanced thermal dissipation characteristics. During the first quarter of 2000, the THS6032 line driver will be offered in the firm’s Microstar BGA PowerPAD package that is said to be one-fifth the size of current ADSL line drivers.