Dual Preamplifier. BA3304F Datasheet
3V dual preamplifier
The BA3304F is a monolithic, dual-preamplifier IC designed for 3V applications. It has been designed especially for low-
The preamplifiers can be directly coupled to the head to minimize the “pop” noise at power on. When combined with the
Rohm BA5204, it is a simple matter to design a high-performance circuit for cassette players.
3V headphone stereos, 3V micro-cassette players and
low-voltage stereo equipment
1) Low noise (VNIN = 1.2µVrms).
2) Input coupling capacitors not required.
3) No input coupling capacitors means high bass stabil-
4) Good channel balance.
5) Built-in bias circuit minimizes “pop” noise.
6) Emitter-follower output for low output impedance.
7) Good low voltage characteristics (operation possible
from Typ. 1.2V).
FAbsolute maximum ratings (Ta = 25_C)
FInternal circuit configuration
FDescription of circuit (see Fig. 1)
As shown in the equivalent circuit for the BA3304 in Fig.
1, the first stage is a differential amplifier. This gives good
stability with respect to temperature and supply voltage
variation, and improves resistance to earth and power
The second stage uses Darlington pairs to increase the
input impedance and the gain of the first stage. The out-
put is an emitter follower which suppresses deterioration
of the linearity due to the influence of the equalizer termi-
nal, and prevents drop in maximum output.
FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 3V, f= 1kHz and RL = 10Ω)