Datasheet

VIN VOUT
GND
EN
TPS7A6201
10µF
to
22µF
1µF
to
10µF
VIN
VOUT
0.1µF
VEN
0.1µF
R1
FB
R2
0
0.5
1
1.5
2
2.5
3
3.5
4
0 25 50 75 100 125
Ambient Air Temperature (°C)
JESD 51-5 (KTT)
JESD 51-3 (KTT)
Power Dissipated (W)
150
TPS7A6201-Q1
SLVSAA0B –NOVEMBER 2010–REVISED MARCH 2012 www.ti.com
APPLICATION INFORMATION
I
QUIESCENT
= quiescent current
Typical application circuit for TPS7A6201 is shown in
Figure 23. Depending upon an end application, As I
QUIESCENT
<< I
OUT
, therefore, the term
different values of external components may be used. I
QUIESCENT
× V
IN
in Equation 3 can be ignored.
In order to program the output voltage, feedback
For device under operation at a given ambient air
resistors (R1 and R2) should be carefully selected.
temperature (T
A
), the junction temperature (T
J
) can
Using small resistors will result in higher current
be calculated using Equation 4.
consumption, where as, using very large resistors will
T
J
= T
A
+ (θ
JA
× P
D
) (4)
impact the sensitivity of the regulator. Therefore, It is
recommended to select feedback resistors such that
Where,
the sum of R1 and R2 is between 20kΩ and 200kΩ.
θ
JA
= junction to ambient air thermal impedance
Also, the overall tolerance of the regulated output
voltage depends on the tolerance of internal
The rise in junction temperature due to power
reference voltage and external feedback resistors.
dissipation can be calculated using Equation 5.
ΔT = T
J
– T
A
= (θ
JA
× P
D
) (5)
A larger output capacitor may be required during fast
load steps to prevent output from temporarily
For a given maximum junction temperature (T
J-Max
),
dropping down. A low ESR ceramic capacitor with
the maximum ambient air temperature (T
A-Max
) at
dielectric of type X5R or X7R is recommended.
which the device can operate can be calculated using
Additionally, a bypass capacitor can be connected at
Equation 6.
the output to decouple high frequency noise as per
T
A-Max
= T
J-Max
– (θ
JA
× P
D
) (6)
the end application.
Example
Example
If I
OUT
= 100mA, V
OUT
= 5V, V
IN
= 14V, I
QUIESCENT
=
If the desired regulated output voltage is 5V, upon
250µA and θ
JA
= 30˚C/W, the continuous power
selecting R2; R1 can be calculated using Equation 1
dissipated in the device is 0.9W. The rise in junction
(and vice versa). Knowing V
REF
= 1.23V (typical),
temperature due to power dissipation is 27˚C. For a
V
OUT
= 5V, selecting R2 = 20kΩ, R1 is calculated to
maximum junction temperature of 150˚C, maximum
be 61.3kΩ.
ambient air temperature at which the device can
operate is 123˚C.
For adequate heat dissipation, it is recommended to
solder the thermal pad (exposed heat sink) to thermal
land pad on the PCB. Doing this provides a heat
conduction path from die to the PCB and reduces
overall package thermal resistance. Power derating
curves for TPS7A6201 device in the KTT (D2PAK)
package is shown in Figure 24.
Figure 23. Typical Application Schematic for
TPS7A6201
Power Dissipation and Thermal
Considerations
Power dissipated in the device can be calculated
using Equation 3.
P
D
= I
OUT
× (V
IN
- V
OUT)
) + I
QUIESCENT
× V
IN
(3)
Where,
P
D
= continuous power dissipation
I
OUT
= output current
Figure 24. Power Derating Curves
V
IN
= input voltage
V
OUT
= output voltage
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