AK4955 Datasheet, PDF (56/117 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK/Cap-less VIDEO-AMP/ LDO & DSP

[AK4955]
■ Mono Input and BEEP Generation Circuit
The AK4955 has the MIN pin for external signal input and a BEEP generation circuit. BPM1-0 bits control BEEP mode.
BPM1 bit
0
0
1
1
BPM0 bit
0
1
0
1
BEEP Mode
MIN pin (Internal Resistance mode)
MIN pin (External Resistance mode)
BEEP Generator mode
N/A
Table 43. BEEP Mode Setting (N/A: Not available)
(default)
1. Mono Input (MIN) pin (BPM1-0 bits = “00” or “01”)
When BPM1-0 bits = “00” or “01”, the input signal to the MIN pin is output from the speaker amplifier by setting BEEPS
bit to “1”, and it is output from the stereo lineout amplifier by setting BEEPL bit to “1”. BPVCM bit sets the common
voltage of MIN input amplifier. (Table 44) When BPVCM bit = “1”, maximum value is AVDD Vpp. Set BEEP GAIN
(BPLVL3-0 bits) to keep MIN-Amp output amplitude less than 0.1Vpp.
BPVCM bit
MIN-Amp Common Voltage (typ)
0
1.15V
(default)
1
1.65V
Table 44. Common Potential Setting of MIN-Amp
• Internal Resistance Mode (BPM1-0 bits = “00”)
Input BEEP gain is controlled by BPLVL3-0 bits (Table 45). In this case an external resistor R_i is not necessary.
BPLVL3 bit BPLVL2 bit BPLVL1 bit BPLVL0 bit BEEP Gain
0
0
0
0
0dB
(default)
0
0
0
1
−6dB
0
0
1
0
−12dB
0
0
1
1
−18dB
0
1
0
0
−24dB
0
1
0
1
−30dB
0
1
1
0
−33dB
0
1
1
1
−36dB
1
0
0
0
−39dB
1
0
0
1
−42dB
Table 45. BEEP Output Gain Setting when BPM1-0 bits = “00”
MS1343-E-00
- 56 -
2011/12