Schematics

1 2 3 4
A
B
C
D
4321
D
C
B
A
MIC
LED
KEY
POWER upDate
Earphone
VDDB T
10
VDDB T
7
PWRKEY
8
LX
5
DGND
6
VBAT
4
VUSB
2
DACL
18
ADC10/MIC/PF2
16
BT_OSC I
11
BT_OSC O
12
BT_ANT
9
VDDIO
3
VDDDAC
19
AGND
1
RFGND
0
VCMBUF
17
VDDPA
20
ADC6/PB4
13
ADC5/PB3
14
ADC2/PA7
15
U1
AB5 61 6A QFN20 3*3
Y1
26MHZ
OSCO
OSCI
upDate1
VDDDAC C10 105
DACL#
DACL MICIN
C14
47 5
VDDB T PWRKEY
C2
NC
C4
0R
C5
2.2pF
C3
105
VUSB
VDDIO
VBATC12 22 5
C13 NC
C11 10 5
L1
10uH
VDDB T
BLUE_LED
LED2 RED
LED1 BLUE
CHRG_LED
BLUE_LED
CHRG_LED
PW RKEY
LOUT1
LOUT#1
DACL#
DACL
C8
NC
C1
NC
MICIN
+
M1
VUSB
VBAT
VUSB1
GND1
R1
5pF
40 13
32 16
ANT1
Touch PAD1
C16
10pF
C15
10pF
C6
10pF
B-
B+