Setup
2
Setup
This section describes the jumpers and connectors on the EVM as well as how to properly connect, set
up, and use the TPS7A3301EVM.
2.1
Input/Output Connectors and Jumper Descriptions
2.1.1
J1
—
(
–
)Vin
Negative input power supply voltage connector. The negative input lead and ground return lead from the
input power supply should be twisted and kept as short as possible to minimize EMI transmission.
Additional bulk capacitance should be added between J1 and J3 if the supply leads are greater than six
inches. For example, an additional 47-
µ
F electrolytic capacitor connected from J1 to ground can improve
the transient response of the TPS7A3301 while eliminating unwanted ringing on the input due to long wire
connections. A (+) power supply may be used if the (+) lead is connected to J2 (GND) and the GND lead
is connected to J1 (
–
VIN).
2.1.2
J2
—
GND
Ground-return connector for the input power supply
2.1.3
J3
—
(
–
)Vout
Regulated (
–
) output voltage connector
2.1.4
J4
—
GND
Output ground-return connector
2.1.5
JP1
—
EN
Output enable. To enable the output, connect a jumper to short the ON pin 1 to the EN center pin 2. To
disable the output, connect a jumper to short EN pin 2 to OFF pin 3.
2.2
Equipment Setup
•
Turn off the input power supply after verifying that its output voltage is set to greater than
–
15 V (
–
18 V
recommended;
–
36 V maximum). Connect the negative voltage lead from the input power supply to
–
VIN, at the J1 connector of the EVM. Connect the ground lead from the input power supply to GND at
the J2 connector of the EVM. If using a (+) power supply, connect the (+) lead is to J2 (GND) and the
GND lead J1 (
–
VIN).
•
Connect desired (
≤
1 A) load between the
–
VOUT pin at connector J3, and the GND pin at connector
J4. Be careful to calculate the power dissipation across the part for the desired
–
VIN level.
3
Operation
•
Turn on the input power supply. For initial operation, it is recommended that the input power supply,
–
VIN on J1, be set to
–
18 V.
•
Vary the load and
–
VIN voltage as necessary for test purposes.
4
Adjustable Operation
The nominal output voltage for the typical LDO circuit employing the TPS7A3301 is set by two external
resistors, R1and R2, as illustrated in
. R1 and R2 can be calculated for any output voltage using
and the Vref voltage found in the device data sheet under the Electrical Characteristics.
2
TPS7A3301EVM-061
SLVU602
–
November 2011
Copyright
©
2011, Texas Instruments Incorporated