AS1310
Datasheet - Application Information
9.1.2 Thermal Shutdown
To prevent the AS1310 from short-term misuse and overload conditions the chip includes a thermal overload protection. To block the normal
operation mode all switches will be turned off. The device is in thermal shutdown when the junction temperature exceeds 150°C. To resume the
normal operation the temperature has to drop below 140°C.
A good thermal path has to be provided to dissipate the heat generated within the package. Otherwise it’s not possible to operate the AS1310 at
its usable maximal power. To dissipate as much heat as possible from the package into a copper plane with as much area as possible, it’s
recommended to use multiple vias in the printed circuit board. It’s also recommended to solder the Exposed Pad (pin 9) to the GND plane.
Note: Continuing operation in thermal overload conditions may damage the device and is considered bad practice.
9.2 Always On Operation
In battery powered applications with long standby times as blood glucose meters, remote controls, soap dispensers, etc., a careful battery
management is required. Normally a complex power management control makes sure that the DCDC is only switched on, when it is really
needed. With AS1310 this complex control can be saved completely, since the AS1310 is perfectly suited to support always-on operations of the
application. The efficiency at standby currents of e.g. 2µAs is around 45% (see Figure 17).
Figure 17. Efficiency vs. Output Current for Always ON Operation
100
L1: XPL2010-682M
90
80
70
60
50
40
30
20
Vin =1.1V
10
Vin = 1.5V
0
0.001
0.01
0.1
1
10
100
Output Current (mA)
9.3 Component Selection
Only four components are required to complete the design of the step-up converter. The low peak currents of the AS1310 allow the use of low
value, low profile inductors and tiny external ceramic capacitors.
9.4 Inductor Selection
For best efficiency, choose an inductor with high frequency core material, such as ferrite, to reduce core losses. The inductor should have low
DCR (DC resistance) to reduce the I²R losses, and must be able to handle the peak inductor current without saturating. A 6.8µH inductor with a
>500mA current rating and <500mΩ DCR is recommended.
Table 4. Recommended Inductors
Part Number
XPL2010-682M
EPL2014-682M
LPS3015-682M
LPS3314-682M
LPS4018-682M
XPL7030-682M
L
DCR
Current Rating
0.62A
Dimensions (L/W/T)
2.0x1.9x1.0 mm
2.0x2.0x1.4 mm
3.0x3.0x1.5 mm
3.3x3.3x1.3 mm
3.9x3.9x1.7 mm
7.0x7.0x3.0 mm
Manufacturer
6.8µH
6.8µH
6.8µH
6.8µH
6.8µH
6.8µH
421mΩ
287mΩ
300mΩ
240mΩ
150mΩ
59mΩ
0.59A
0.86A
Coilcraft
www.coilcraft.com
0.9A
1.3A
9.4A
www.austriamicrosystems.com/DC-DC_Step-Up/AS1310
Revision 1.8
14 - 19
AMSCO [ AMS(艾迈斯) ]
