Datasheet

TPS72201, TPS72215
TPS72216, TPS72218
SLVS390B – DECEMBER 2001 – REVISED MAY 2002
www.ti.com
8
TPS72215
1.8 V 1.5 V
Boost Converter
3.3 V
1.8 V – 3 V
V
IO
V
CORE
DSP or
Controller
Two AAA
Batteries
Figure 17. Dual Supply Application Circuit
EXTERNAL CAPACITOR REQUIREMENTS
A 0.1-µF ceramic bypass capacitor is required on both the input and output for stability. Larger capacitors improve transient
response, noise rejection, and ripple rejection. A higher value electrolytic input capacitor may be necessary if large, fast
rise time load transient are anticipated, and/or there is significant input resistance from the device to the input power supply.
POWER DISSIPATION AND JUNCTION TEMPERATURE
Specified regulator operation is assured to a junction temperature of 125°C; the maximum junction temperature allowable
without damaging the device is 150°C. This restriction limits the power dissipation the regulator can handle in any given
application. To ensure the junction temperature is within acceptable limits, calculate the maximum allowable dissipation,
P
D(max)
, and the actual dissipation, P
D
, which must be less than or equal to P
D(max)
.
The maximum-power-dissipation limit is determined using the following equation:
P
D(max)
+
T
J
max * T
A
R
qJA
Where:
T
J
max is the maximum allowable junction temperature.
R
θJA
is the thermal resistance junction-to-ambient for the package, see the power dissipation rating
table.
T
A
is the ambient temperature.
The regulator dissipation is calculated using:
P
D
+
ǒ
V
I
* V
O
Ǔ
I
O
Power dissipation resulting from quiescent current is negligible.