Preview
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Setup
RENT
§
·
Enable_ Voltage VIH_EN 1ꢀ
¨
¸
¹
RENB
©
where
•
VIH_EN is 2.2 V (typ)
(1)
PG – Testpoint—is used to monitor the power good flag. This flag indicates whether the output voltage
has reached its regulation point. This terminal is an open-drain output that requires a pullup resistor
to the appropriate logic voltage (any voltage less than 14 V). A pre-installed resistor RPG1 of 100
kΩ is tied to the PG terminal and brought out to the PG_PULL UP test point.
PG_PULL UP – Testpoint—is the top connection of the pre-assembled 100-kΩ RPG1 pullup resistor that
ties directly to the open-drain PG terminal. Supply an appropriate voltage to this test point, or tie it
directly to the VOUT test point to observe the PG flag operation.
BIAS – Testpoint—is used to monitor the BIAS voltage. A pre-installed capacitor of 4.7 µF is connected
from the BIAS terminal to ground (GND). This node is connected to VOUT through a zero Ohm
resistor pre-installed on the bottom layer, labeled (RBIAS).
SYNC – Testpoint —is the input terminal for an optional external input clock to the converter. The
external clock frequency must be between 200 kHz and 2.2 MHz, if used. A pulldown resistor of
100 kΩ (RSYNC) is installed on the EVM.
SW – Testpoint—is used to monitor the voltage on the switch terminal and the switching frequency of the
voltage regulator. Remove this test point before making any electromagnetic interference (EMI)
measurements.
VSUPPLY – Edge Connector terminal #9—is used to supply the input voltage through an on board LC
filter (if one is needed for conducted EMI/EMC measurements). The Lin and Cd component pads
are located on the bottom side of the EVM. Please refer to the EVM schematic for initial suggestion
of component values.
4
5
Setup
Set the input voltage (VIN) range for the converter between the operating voltage range of 3.5 V to 60 V. If
a load is driven, it should be applied to the VOUT terminal and should not exceed the maximum load
current of 1 A.
Operation
For proper operation of the LM46001, VIN, GND, and VOUT should be properly configured as stated
above. In this configuration, the device will start up when power is applied and the output voltage of the
regulator (VOUT) will come up to the proper value. The default setting for output voltage of the
LM46001EVM is 3.3 V. Other output voltages can be set by replacing the feedback terminal resistor
dividers RFBT and RFBB; please consult the datasheet for proper selection of these resistor values.
The default frequency for the LM46001EVM is 500 kHz. If other frequencies are desired, within the
frequency range of 200 kHz and 2.2 MHz, the RT resistor value can be changed. Please consult the
datasheet for proper selection of the RT resistor. You must change inductor (L_60V_LC) and total output
capacitance for proper control loop operation.
3
SNVU422–June 2014
LM46001EVM User Guide
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