LM25061MM-2EVAL National Semiconductor, LM25061MM-2EVAL Datasheet - Page 16

• Manufacturer Part Number: LM25061MM-2EVAL
• Description: BOARD EVALUATION LM25061
• Manufacturer: National Semiconductor

Specifications of LM25061MM-2EVAL

• Main Purpose: Power Management, Hot Swap Controller
• Embedded: No
• Utilized Ic / Part: LM25061-2
• Primary Attributes: High Side MOSFET Driver, Inrush Current Limiting
• Secondary Attributes: Auto Restart, 2.9 V ~ 17 V Supply
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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The two resistor values are calculated as follows:
(V
As an example, assume the application requires the following
thresholds: V
The resistor values are:
Where the resistor values are known, the threshold voltages
and hysteresis are calculated from the following:
Option B: The minimum UVLO level is obtained by connect-
ing the UVLO pin to VIN as shown in Figure 12. Q1 is switched
on when the VIN voltage reaches the POR threshold (
UVL
- Choose the upper and lower UVLO thresholds (V
FIGURE 11. Programming the UVLO Thresholds
).
UVH
FIGURE 12. UVLO = POR
= 8V, V
R1 = 50 kΩ, R2 = 10 kΩ
V
UV(HYS)
UVL
= R1 x 20 µA
= 7V.Therefore V
UV(HYS)
UVH
≊
30090341
2.6V).
= 1V.
) and
30090329
16
POWER GOOD and FB PINS
During turn-on, the Power Good pin (PGD) is high until the
voltage at VIN increases above
low, remaining low as the VIN voltage increases. When the
voltage at the FB pin increases above its threshold PGD
switches high. PGD switches low when the voltage at the FB
pin is below the programmed threshold, or if the UVLO pin is
taken below its threshold. Setting the output threshold for the
PGD pin requires two resistors (R3, R4) as shown in Figure
13. While monitoring the output voltage is shown in Figure 13,
R3 can be connected to any other voltage which requires
monitoring.
The resistor values are calculated as follows:
- Choose the upper and lower threshold (V
at V
As an example, assume the application requires the following
thresholds: V
(HYS)
Where the R3 and R4 resistor values are known, the threshold
voltages and hysteresis are calculated from the following:
A pull-up resistor is required at PGD as shown in Figure 14.
The pull-up voltage (V
be higher or lower than the voltages at VIN and OUT.
OUT
= 0.5V. The resistor values are:
FIGURE 13. Programming the PGD Threshold
.
PGDH
R3 = 22.7 kΩ, R4 = 2.68 kΩ
= 11V, and V
V
PGD(HYS)
PGD
) can be as high as 17V, and can
= R3 x 22 µA
PGDL
≊
1.6V. PGD then switches
= 10.5V. Therefore V
PGDH
30090350
) and (V
PGDL
PGD
)