Datasheet

2.2 J4/J6 – Output Connections
2.3 JP1 – EN
2.4 J2/J4 - Vin Sense and Vout Sense
3 Operation
4 Test Results
5 Board Layout, Schematic, and Bill of Materials
5.1 Board Layout
Operation www.ti.com
This is the connection for the output of the TPS61220EVM. Connect the positive connection of the load to
the Vout J4 and the negative connection to the GND J6.
This is the enable input for the device. Place a shorting jumper across the ON and EN pins of JP1 to
enable the integrated circuit (IC). Place a shorting jumper across the OFF and EN pins of JP1 to disable
the IC. A shorting jumper must be installed on JP1 in either the ON or OFF positions, and EN must not be
left unconnected.
The two connectors are not installed, but if very accurate measurements of input or output voltage are
required J2 or J4 can be installed for the measurements. Traces on the PCB connect to the input or output
capacitor and run independent of the output and ground lines to the two connectors.
Connect the positive input power supply to the Vin J1 and GND J3. Typical input voltage is 0.7 V to 3 V for
this configuration of output voltage. The TPS61220EVM-319 has a maximum input voltage of 5.5 V with
correct output voltage.
Connect the desired load between the Vout J4 and GND J6. The TPS61220 maximum output current
depends on the conversion ratio between input and output along with Vout; consult the data sheet for
additional information.
Configure jumper JP1 as required; the EN pin is not pulled up or down inside the device or on the EVM.
JP1 must be installed for proper operation. ON is normal operation. In the OFF position, the device is shut
down and switching has stopped.
Note that the device does not disconnect the input from the output during a shutdown condition. The
voltage is reduced through impedance of the TPS61220 and varies with load; at light load, voltage drop is
about 700 mV.
See the Typical Characteristics section of the TPS61220 data sheet. This EVM uses the same inductors
and capacitors as those used for characterization in the data sheet. Performance is consistent with that
shown in the data sheet.
This section provides the TPS61220EVM-319 board layout, schematic, and bill of materials.
Board layout is critical for all high-frequency, switch-mode power supplies. If the layout is not done
carefully, the regulator can show stability problems as well as EMI problems. Therefore, use wide and
short traces for the main current path and for the power ground tracks. The input and output capacitor, as
well as the inductor, must be placed as close as possible to the IC. Use a common ground node for power
ground to minimize the effects of ground noise. Figure 1 through Figure 3 show the board layout for the
TPS61220EVM-319 PCB.
2 TPS61220EVM-319 SLVU253 – February 2009
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