EN connected to GND
The converter is OFF
EN connected to VIN
The converter is ON when the VIN
voltage is above the VIN UVLO
rising threshold
EN connected to VIN through a resistor divider
The converter is ON when the divider voltage is
above the EN rising threshold and the VIN
voltage is above the VIN UVLO
EN connected to the xEN terminal
Provide enable signal at the xEN
to turn the device ON
MODE connected to VIN
FPWM is enabled
MODE connected to GND
Auto PFM is enabled
Provide external clock at
SYNC to synchronize the
switching frequency
PGOOD pullup voltage
connected to VOUT
PGOOD pullup voltage connected to Vx
Provide external voltage at Vx for the
PGOOD flag logic HIGH level
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Getting Started
5
SNVU578A – October 2017 – Revised March 2018
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User's Guide for the LMZM23601 and LMZM23600 Evaluation Boards
Figure 3. Jumper Configuration Details for Each Board
Before applying power to the EVM, ensure that all of the jumpers are in place and are properly positioned
for the intended feature setting and output voltage operation. Always shut down the input power supply
before changing any of the jumper settings.
Figure 1
and
Figure 3
above provide an overview of the board
connection terminals, jumper setting options, and test points.
Use the "VIN POWER TERMINAL" and "GND TERMINAL" turrets to connect the board to the input
supply. Connect the load between the "VOUT TERMINAL" and "GND TERMINAL".
For the adjustable output version of the board, the output voltage setting jumper configures the feedback
resistor divider pair for various popular output voltages: 2.5 V, 3.3 V, 5 V, 12 V, or 15 V. Voltage sense
points are provided to help read the input voltage and output voltage directly at the regulator. The sense
lines should not be used for power connections. There are several test points provided on the left hand
side of the board. They can be used to monitor the voltage signals at the MODE, EN, and PG pins of the
device.
The EN selection jumper allows the user to select the desired enabling scheme for the end application.
The LMZM23600 and LMZM23601 feature a precision enable input which can be used to set the input
UVLO point with a voltage divider from the input voltage. Alternatively, the enable input can be driven by a
logic signal or it could be tied directly to VIN for an always-on operation.
The MODE selection jumper sets the DC/DC converter mode of operation at light load. When Auto PFM
mode is selected, the converter will enter PFM mode at light load and reduce the switching frequency in
order to maintain high conversion efficiency. Some applications may require that the regulator maintains
constant switching frequency across the entire load range. In such cases the mode pin can be used to set
forced PWM operation at light load. The mode terminal can also be used to synchronize the converter
switching frequency to an external clock. If frequency synchronization is used, the converter will operate in
forced PWM mode at light load.
The PGOOD flag jumper allows the user to either connect the PGOOD pullup resistor to VOUT or provide
an external voltage rail for the logic HIGH voltage level.
