Datasheet
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Operation
Table 1. Output Voltage Setting
Output Voltage Jumper Between Pins
1.5 1 and 2
1.8 3 and 4
2.8 5 and 6
3.3 7 and 8
Other output voltages can be configured by changing the feedback resistors on the board.
The pins of JP2 connect directly to the feedback network of the TPS73401.
The feedback network is high impedance and sensitive to noise or resistance value changes. The pins of
JP2 should not be touched while the device is powered since the impedance of a human is enough to
alter the output voltage set point. The output voltage may increase or decrease if JP2 is touched which
may damage any load connected to the EVM.
3 Operation
Connect the positive input power supply to J1. Connect the input power return (ground) to J2. The
TPS73401EVM has an absolute maximum input voltage of 7.0V. The recommended maximum operating
voltage is 6.5V. The actual highest input voltage may be less than 6.5V due to thermal conditions. See the
Thermal Considerations section of this manual to determine if the highest input voltage.
Connect the desired load between J3 (positive lead) and J4 (negative or return lead). Configure jumper
JP2 for the desired output voltage. The function of JP2 is described in the Setup section (2.1.5) of this
manual.
3.1 Fixed Output TPS734xx
The TPS73401 EVM can be used to evaluate fixed output voltage versions of the TPS734xx. The board
layout and part footprints are the same between the adjustable version and fixed output voltage versions
of the TPS734. To evaluate a fixed output voltage version, the IC on the board will need to be changed to
the desired fixed output voltage TPS734xx. R1 must be shorted or removed from the EVM board and
replaced with a zero ohm resistor. C3 must be removed and left open. There should not be any jumpers
installed on JP2 for fixed output voltage version parts.
4 Thermal Guidelines
This chapter provides guidelines for the thermal management of the TPS73401DRVEVM-527 board.
4.1 Thermal Considerations
Thermal management is a key component of design of any power converter and is especially important
when the power dissipation in the LDO is high. To better help you design the TPS73401 family into your
application, the following formula should be used to approximate the maximum power dissipation at a
particular ambient temperature:
T
J
= T
A
+ P
d
× θ
JA
(1)
where
T
J
is the junction temperature,
T
A
is the ambient temperature,
P
d
is the power dissipation in the IC and
θ
JA
is the thermal resistance from junction to ambient.
All temperatures are in degrees Celsius.
The measured thermal resistance from junction to ambient for the TPS73401EVM has a typically value of
38˚C/W. The recommended maximum operating junction temperature specified in the datasheet for the
TPS73401 family is 125°C. With these two pieces of information, the maximum power dissipation can be
found by using Equation 1.
Example Calculation:
3
SLVU333A–August 2009–Revised March 2012 TPS73401DRV EVM
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