S42
Hardware User Guide
1VV0301303 Rev. 11
Page 13 of 85
2021-05-06
Not Subject to NDA
3.
APPLICATION INTERFACE
3.1.
Power Supply
S42 require a power supply with the following characteristics:
Typical: 3,0V
DC
, min.: 1,7V
DC
, max.: 3,6V
DC
, thereby delivering > 25 mA peak
S42 is designed to be powered from 3V coin cell batteries e.g. CR2032 directly,
or any other power source complying with the given requirements. For optimal
performance, a stable supply is recommended. Furthermore, it is recommended to place
a capacitor in parallel to the CR2032 3V coin cell battery in order to prolong battery
lifetime, by compensating the effects of the rising source resistance of the battery to
pulsed loads. Since the isolation resistance of this capacitor will discharge the battery in
a not insignificant scale, the capacitor should be chosen under consideration of the
following rules:
•
Capacitance as small as necessary
•
Nominal voltage as high as possible
•
Case size as large as possible
•
Use X7R instead of X5R
In case of using an NFC antenna in conjunction with batteries attend to chapter 3.8.2
Power Back Feeding.
S42
XC6209F-3.3
E-6,F-6
VSUP
GND:
A-7,E-7,F-7,B-[5:8],
C-[5:8],D-8,E-8,F-8
1µ + 100n
1µ
VOUT
VSS
VIN
CE
5
1
3
2
+5VDC
Figure 2: S42 Example Power Supply with LDO
