  The POLARBEAR-2 CosmicMicrowave Background (CMB) experiment aims to observe
B-mode polarization with high sensitivity to explore gravitational lensing of
CMB and inflationary gravitational waves. POLARBEAR-2 is an upgraded experiment
based on POLARBEAR-1, which had first light in January 2012. For POLARBEAR-2,
we will build a receiver that has 7,588 Transition Edge Sensor (TES) bolometers
coupled to two-band (95 and 150 GHz) polarization-sensitive antennas. For the
large array's readout, we employ digital frequency-domain multiplexing and
multiplex 32 bolometers through a single superconducting quantum interference
device (SQUID). An 8-bolometer frequency-domain multiplexing readout has been
deployed on POLARBEAR-1 experiment. Extending that architecture to 32
bolometers requires an increase in the bandwidth of the SQUID electronics to 3
MHz. To achieve this increase in bandwidth, we use Digital Active Nulling (DAN)
on the digital frequency multiplexing platform. In this paper, we present
requirements and improvements on parasitic inductance and resistance of
cryogenic wiring and capacitors used for modulating bolometers. These
components are problematic above 1 MHz. We also show that our system is able to
bias a bolometer in its superconducting transition at 3 MHz.
