BU7150NUV_15 Datasheet, PDF (13/22 Pages) Rohm – Headphone Amplifier Designed for 0.93V Low Voltage Operation

BU7150NUV
Technical Note
・Single-Ended mode
Single-ended mode can be use for stereo headphone amplifier using two internal amplifiers. BU7150NUV can select
amplifier gain Av using external parts. (Fig. 34) Two amplifiers gain Av is decided by input resistance RI1, RI2 and feedback
resistance RF1, RF2 aspect. Also, Please, use RF1, RF2 value in the range 20kΩ~1MΩ.
A_V
=
− ^RF
R_I
Amplifier outputs (OUT1, OUT2) need coupling capacitors in single-ended mode operation. Coupling capacitors reduce
DC-voltage at the output and to pass the audio signal.
Single-ended mode has mute mode. Mute mode reduces pop noise and low power (typ. 15µAwhen MUTEB pin = Low.
Rise time is high-speed though current consumption increases more than the state of the shutdown so that the state of
the mute may keep the output level at the bias level. Mute level is decided by input resistance RI1, RI2 and feedback
resistance RF1, RF2 and RL
Mute level [dB] = 20Log ^RL
R_I + R_F
BU7150NUV needs phase-compensation circuit using external parts. (Fig. 34) But, for amplifier gain Av > 4 then phase
compensation circuit may be eliminated.
・BTL mode
BTL mode can be used for mono speaker amplifier using two internal amplifiers. BU7150NUV can select amplifier gain Av
using external parts. (Fig. 35) 1st stage gain is decided by selecting external parts. But 2nd stage gain = 1. 1st stage
output signal and 2nd stage output signal are of same amplitude but phase difference of 180°.
Amplifiers gain Av is decided by input resistance RI1 and feedback resistance RF1 aspect. Also, Please, use RF1, RF2 value
in range of 20kΩ~1MΩ.
A_V
= 2 ∗ ^RF1
R_I1
BU7150NUV has no output pop noise at BTL mode operation, because output coupling capacitor is not charged.
Therefore, BTL mode is faster by 11 times compared to single-ended mode. SDB pin and MUTEB pin are same function
in BTL mode operation.
www.rohm.com
© 2015 ROHM Co., Ltd. All rights reserved.
13/18
2015.1 - Rev.E