Datasheet

Evaluation Board User Guide UG-199
Rev. 0 | Page 3 of 8
EVALUATION BOARD OVERVIEW
The ADP2121 evaluation board is fully assembled and tested.
The following sections describe the various connectors on the
board, the proper evaluation setup, and the testing capabilities
of the evaluation board.
INPUT/OUTPUT CONNECTORS
EN Jumper (JP1)
The EN connector enables or disables the converter. Use one of
the following methods to control the state of the EN pin. Do not
leave the EN pin floating.
• Disable the converter by using a jumper to connect the left-
most pins of JP1. The jumper connects the EN pin to GND,
effectively disabling the converter (see Figure 2).
PLACE JUMPER HERE
09420-002
Figure 2. SD Jumper Position
• Enable the converter by using a jumper to connect the
right most pins of JP1. The jumper connects the EN pin to
VIN, effectively enabling the converter (see Figure 3).
PLACE JUMPER HERE
0
9420-003
Figure 3. EN Jumper Position
• Directly control the EN pin by connecting an external
device to the center pin of JP1 (see Figure 4). Apply a
voltage between GND and VIN.
CONNECT EXTERNAL
DEVICE HERE
09420-004
Figure 4. EN Pin Direct Connection
MODE Jumper (JP2)
The MODE connector controls the operating mode of the
ADP2121. Use one of the following methods to select between
automatic PFM/PWM switching and forced PWM operation.
Do not leave the MODE pin floating. The MODE pin is not
designed for dynamic control and should not be changed after
the ADP2121 is enabled.
• Place the converter in auto mode by using a jumper to connect
the left most pins of JP2. The jumper connects the MODE
pin to GND to use the power save mode with automatic
transition between PFM and PWM mode (see Figure 5).
PLACE JUMPER HERE
09420-005
Figure 5. Auto Mode Jumper Position
• Place the converter in forced PWM mode by using a
jumper to connect the right most pins of JP2. The jumper
connects the MODE pin to VIN, effectively forcing the
converter to remain in PWM mode, regardless of the size
of the applied load (see Figure 6).
PLACE JUMPER HERE
09420-006
Figure 6. PWM Mode Jumper Position
• Control the voltage applied to the MODE pin directly by
connecting an external device to the center pin of JP2 (see
Figure 7). Apply a voltage between GND and VIN.
CONNECT EXTERNAL
DEVICE HERE
09420-007
Figure 7. MODE Pin Direct Connection
VOUT Test Bus (TB1)
The VOUT test bus provides access to the regulated output
voltage and the FB (feedback) pin of the part. A load of up to
600 mA can be applied to this bus.
VIN Test Bus (TB2)
The VIN test bus connects the positive input supply voltage to
the VIN pin. Connect the power supply to this bus and keep the
wires as short as possible to minimize EMI transmission.
PGND Test Bus (TB3)
The PGND test bus is the power ground connection for the part
and the external components via the GND pin. Attach ground
connections from external equipment to this bus.
SW Test Point (TP1)
The SW test point allows access to the switch node (SW pin) of
the ADP2121 to monitor the switching behavior. An LC filter is
connected to this pin on the board. Connect a BNC cable to
measure the switching frequency to this test point.