LM25061MM-2EVAL/NOPB National Semiconductor, LM25061MM-2EVAL/NOPB Datasheet - Page 3

• Manufacturer Part Number: LM25061MM-2EVAL/NOPB
• Description: EVAL BOARD FOR LM25061MM-2
• Manufacturer: National Semiconductor

Specifications of LM25061MM-2EVAL/NOPB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The UVLO thresholds are set by resistors R1 and R2 and the
PGD thresholds are set by resistors R3 and R4. Internal cur-
Board Layout and Probing Cautions
The pictorial in Figure 1 shows the placement of the circuit
components. The following should be kept in mind when the
board is powered:
1.
2.
Use CAUTION when probing the circuit to prevent injury,
as well as possible damage to the circuit.
At maximum load current (5A), the wire size and length
used to connect the power source and the load become
important. The wires connecting this evaluation board to
the power source SHOULD BE TWISTED TOGETHER
to minimize inductance in those leads. The same applies
for the wires connecting this board to the load. This
recommendation is made in order to minimize high
voltage transients from occuring when the load current is
shut off.
FIGURE 3. Power Up Using Power Limit and Current Limit
3
rent sources at the UVLO pin and the FB pin provide hystere-
sis for the thresholds.
Board Connections/Startup
The input voltage source is connected to the J1 connector,
and the load is connected to the J2 connector at the OUT and
GND terminals. USE TWISTED WIRES. A voltmeter should
be connected to the input terminals, and one to the output
terminals. The input current can be monitored with an amme-
ter or current probe. To monitor the status of the PGD output,
connect a voltmeter from PGOOD to GND on the J2 terminal
block. Put the toggle switch in the ON position.
Increase the input voltage gradually. The input current should
remain less than 2 mA until the upper UVLO threshold is
reached. When the threshold is reached, Q1 is turned on as
described in the Theory of Operation section. If viewed on an
oscilloscope, the input current increases as shown in Figure
3 before settling at the value defined by the load. The turn-on
timing depends on the input voltage, power limit setting, cur-
rent limit setting, and the final load current, and is between
≊
current, with VIN = 14V. See Figures 9 and 10.
3.0 ms with no load current, and
30091403
≊
6.5 ms with a 3.7A load
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