Eurotech BitsyXb - Power Supply

BitsyXb - User Manual
58 110118-0001A
6.3.4 Power Supply
Absolute Maximum Ratings
Supply Voltage (DCIN_POS) ..................................... 18 V
Symbol
Parameter
Min
Typ.
Max
Units
System Power
VBATT_POS
BitsyXb supply voltage (Note 15)
5
12
15
V
Vdin
Diode drop from DCIN_POS to
VBATT_POS at 130 mA
0.35 0.4 V
VDDI
Processor core voltage (6.3.9)
0.85
1.0
1.3
V
VDDX 3.3 V onboard supply
Run
3.1
3.3
3.5
V
Sleep
3.15
V
VCC
5.0 V onboard supply
4.75
5.0
5.25
V
I (Vcc)
5 V available for display,
PCMCIA, USB, J9.15,
J10.48, etc. (Note 16)
Run
500 mA
Sleep
I (Vddx)
3.3 V available for
display, PCMCIA, J9.23,
J10.47, etc. (Note 17)
Run 700 mA
Sleep 100 mA
RTC Backup Power (4.2)
V BATPOS
real-time clock battery backup
2.2
3.0
3.6
V
I BATPOS
RTC current (note 18)
300
500
nA
Battery Trickle Charger (5.3.7)
Rch
Charger series resistance
37.5
Ω
Pch
Charge resistor power rating
0.25
W
Notes:
15. The system can operate down to the minimum voltage shown, but the DC_GOOD signal
may cause the system to go to sleep when running at that voltage. See Power Failure
Interrupt in section 5.3.3 for details. The power failure feature can be overridden.
16. LTC 1771 "Burst" mode, used when the BitsyXb is in Sleep mode, is more efficient at low
currents. However, it is electrically noisier and can cause significantly greater EMI/RFI at
higher current draws.
17. During Sleep mode, Vddx is powered by a linear regulator, which draws from the 5V
supply.
18. Vddx=0V, Vbatpos=3.2 V (source: DS1307 data sheet)