Michael Asam

A load-insensitive quad-band GSM/EDGE SiGeC-bipolar power amplifier with a highly efficient low power mode

A load-insensitive fully-integrated quad- band GSM/EDGE radio frequency power amplifier for 824-915 MHz and 1710-1910 MHz has been realized in a 0.35-mum SiGeC-Bipolar technology. The chip integrates a low- and high-band 3-stage power amplifier including a bias-control circuit for power control, band select and mode as well as ramping dependent quiescent currents. The load-insensitive balanced PA architecture delivers for an adjusted output power of 34.5 dBm for all phases of a 3:1 VSWR a low deviation only 1.3 dB. At 3.5 V a saturated output power of 36.7 dBm is achieved at 870 MHz and 34 dBm at 1710 MHz. The respective peak PAE is 52% for low band and 42 % for high-band. The PA features a unique switched low power mode that involves disabling one half of each PA.

Failure mechanisms of low-voltage trench power MOSFETs under repetitive avalanche conditions

In this paper we present a mechanism leading to early fails in a trench power MOSFET when operated at high drain currents under repetitive avalanche conditions (also referred to as “unclamped inductive switching”). While typical fails show burn marks at (or under) the bond stitches, early fails can occur close to the active areas edges or corners. With plausible assumptions both cases can be consistently explained by thermal runaway as demonstrated by electrothermal simulation.

Influence of self-heating on ESD current distribution in metal lines

Copper metal lines from a 40nm CMOS technology are investigated by means of TLP, a static DC current-density-check tool and electro-thermal simulations. The role of self-heating during ESD in the current re-distribution across paths of different resistance is demonstrated. Conclusions are drawn for the proper interpretation of static electrical current-density-check results.