AS3525-A/-B C22O22
Data Sheet, Confidential
7.4.20
10-Bit ADC
7.4.20.1 General
This general purpose ADC can be used for measuring several voltages and currents to perform functions like battery monitor, temperature
supervision, button press detection, etc.. . Please note that C21O20 is measuring BVDD instead of CHG_OUT
7.4.20.2 Input Sources
Table 152 ADC10 Input Sources
Nr.
0
Source
CHG_OUT
RTCSUP
Range
5.120V
5.120V
LSB
Description
5mV check battery voltage of 4V LiIo accumulator
1
5mV check RTC backup battery voltage (connected to BVDD inside the
package)
2
3
4
5
6
VBUS
CHG_IN
CVDD
5.120V
5.120V
2.560V
2.560V
2.560V
5mV check USB host voltage
5mV check charger input voltage
2.5mV check charge pump output voltage
2.5mV check battery charging temperature
BatTemp
MicSup1
2.5mV check voltage on MicSup1 for remote control or external voltage
measurement
7
MicSup2
2.560V
2.5mV check voltage on MicSup2 for remote control or external voltage
measurement
8
9
VBE1
VBE2
1.024
1.024
1mV measuring junction temperature
1mV measuring junction temperature
10
I_MicSup1
I_MicSup2
VBAT
1.024mA typ. 1.0uA check current of MicSup1 for remote control detection
1.024mA typ. 1.0uA check current of MicSup2 for remote control detection
11
12
2.560V
1.024V
2.5mV check single cell battery voltage
1mV for testing purpose only
13..15
Reserved
CHG_OUT, RTCSUP, VBUS, CHG_IN
These sources are fed into an 1/5 voltage divider (180kΩ typ.) and further amplified by 2.5.
CVDD, BatTemp, MicSup1, MicSup2
These sources are fed directly to the ADC input multiplexer.
VBE1, VBE2
These inputs are first amplified by 2.5 and than fed to the ADC input multiplexer.
I_MicSup1, I_MicSup2
The measurement of the microphone supply LDOs is not very accurate, as the current-voltage conversion is only done by a single resistor which
shows wide process and temperature variations. These measurements should be only used for remote function detection.
VBAT
This source is divided by 2.5 with a voltage divider (180kΩ typ.) and than amplified by 2.5. This has to be done, as VBAT can represent voltages up
to 3.6V. Please note, that the maximum measurement rage will be still 2.560V
7.4.20.3 Reference
AVDD=2.9V is used as reference to the ADC. AVDD is trimmed to +/-20mV with over all precision of +/-29mV. So the absolute accuracy is +/-1%.
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