User Manual

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MAX98089
Low-Power, Stereo Audio Codec
with FlexSound Technology
Table 35. Battery Measurement Registers
Battery Measurement
The IC measures the voltage applied to SPKLVDD (typically the battery voltage) and reports the value in register 0x03.
This value is also used by the speaker limiter circuitry to set accurate thresholds. When the battery measurement func-
tion is disabled, the battery voltage is user programmable.
Table 34. Jack Detection Registers (continued)
REGISTER BIT NAME DESCRIPTION
0x03
4
VBAT
Battery Voltage
Read VBAT when V
BATEN
= 1 to determine V
SPKLVDD
. Program VBAT when V
BATEN
=
0 to allow proper speaker amplifier signal processing. Calculate/program the battery
voltage using the following formula:
V
BATTERY
= 2.55V + [VBAT/10]
3
2
1
0
0x51
7
SHDN
See the Power Management section.
6 VBATEN
Battery Measurement Enable. Enables an internal ADC to measure V
SPKLVDD
.
0 = Disabled (register 0x03 readable and writeable)
1 = Enabled (register 0x03 read only)
3 PERFMODE See the Power Management section.
2 HPPLYBCK See the Power Management section.
1 PWRSV8K See the Power Management section.
0 PWRSV See the Power Management section.
REGISTER BIT NAME DESCRIPTION
0x4E
7 BGEN See the Power Management section.
6 SPREGEN See the Power Management section.
5 VCMEN See the Power Management section.
4 BIASEN See the Power Management section.
0 JDWK
JACKSNS Pullup
When JDWK = 1, JACKSNS is slow to increase in voltage. Set JDWK = 0 before setting
JDETEN = 1 to prevent false detection.
Valid when MBIAS = 0.
0 = 2.4kI to SPKLVDD (allows microphone detection)
1 = 5FA to SPKLVDD (minimizes supply current)