Texas Instruments LM5175RHF QFN, Руководство пользователя

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Signal Connections and Test Point Descriptions
5 SNVU518 – April 2016
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Copyright © 2016, Texas Instruments Incorporated
LM5175RHF (QFN) EVM User Guide
3 Signal Connections and Test Point Descriptions
3.1 Test Point Descriptions
Table 2. Test Point Descriptions
LABEL DESCRIPTION
VIN Input voltage positive power and sense connection
GND Input voltage negative power and sense connection
VOUT Output voltage positive power and sense connection
GND Output voltage negative power and sense connection
AGND Analog GND
SYNC External frequency synchronization input (SYNC). This terminal is connected to
the RT/SYNC pin of the LM5175 controller through a 100 pF capacitor on the
board.
EN ENABLE input; tie to GND to disable converter
PGOOD Power Good output
3.2 Optional Configurations
Table 3. Optional Configurations
COMPONENT DESCRIPTION
R8
R8 can be used to select DCM or CCM mode and for enabling hiccup mode current
limit. See LM5175 device datasheet for R8 values. Default EVM configuration is
CCM/No hiccup.
Rcd
Dither is disabled by default. Replace with an appropriate capacitor to enable dither.
See LM5175 datasheet on how to set the dither frequency.
3.3 Signal Connections
3.3.1 Input Voltage Monitoring
The LM5175RHFEVM-HD provides two solder lug test points for measuring input voltage at the input
banana connections. This allows the user to measure the actual input voltage without losses from input
cables and connectors. All input voltage measurements should be made between VIN and GND test
points.
3.3.2 Output Voltage Monitoring
The LM5175RHFEVM-HD provides two solder lug test points for measuring output voltage at the output
banana connections. This facilitates measurement of the output voltage without losses related to output
cables and connectors.
3.3.3 Power Good Voltage Output
The LM5175RHFEVM-HD provides a test point for measuring the PGOOD flag voltage. A 20-k Ω pullup
resistor, Rpg, to VCC is included. For true open-drain operation with no pullup, remove Rpg. One possible
scenario where a PGOOD pullup is not required involves PGOOD of an upstream converter connected to
the EN input of a downstream converter to provide sequential startup of multiple regulators.
3.3.4 Enable Voltage Input
The LM5175RHFEVM-HD provides a test point for measuring the EN voltage. Shorting this test point to
GND disables the converter. The EN/UVLO voltage should not exceed the input voltage.