Datasheet

Application ST8024
24/31
6 Application
Figure 10. Application diagram
(1) These capacitors must be of the low ESR-type and be placed near the IC (within 100 mm).
(2) ST8024 and the microcontroller must use the same V
DD
supply.
(3) Make short, straight connections between CGND, C5 and the ground connection to the capacitor.
(4) Mount one low ESR-type 100 nF capacitor close to pin V
CC
.
(5) Mount one low ESR-type 100 nF capacitor close to C1 contact.
(6) The connection to C3 should be routed as far from C2, C7, C4 and C8 and, if possible, surrounded by
grounded tracks.
(7) Optional resistor bridge for changing the threshold of V
DD
. If this bridge is not required pin 18 should be
connected to ground.
CLKDIV2
C1 -
VUP
PRES
PRES
I/O
AUX1
PGND
C1 +
VDDP
AUX2
CGND
1
2
3
4
5
6
7
8
9
10
11
12
13
14 15
16
17
18
19
20
21
22
23
24
25
26
27
28
CLKDIV1
5/3V
CLK
I/OUC
XTAL2
XTAL1
GND
VDD
RSTIN
PORADJ
AUX1UC
AUX2UC
VCC
RST
OFF
CMDVCC
R100K
+3.3V
+5V
100nF
(1)
100nF
100nF
(5)
C1
C2
C3
C4
C5
C6
C7
C8
K1
K2
(2)
+3.3V
100nF
(1)
100nF
10µF
100nF
10µF
15pF
+3.3V
+3.3 V POWERED
MICROCONTROLLER
CARD READER
(normally closed type)
(4)
(3)
(6)
Vdd
R2
R1
(7)
ST8024