LM5067EVAL National Semiconductor, LM5067EVAL Datasheet - Page 5

• Manufacturer Part Number: LM5067EVAL
• Description: NEGATIVE HOT SWAP / INRUSH CURRE
• Manufacturer: National Semiconductor

Specifications of LM5067EVAL

• Main Purpose: Power Management, Hot Swap Controller
• Utilized Ic / Part: LM5067
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

UVLO/OVLO Input Voltage
Thresholds
As supplied, the input voltage UVLO thresholds on this eval-
uation board are approximately 34.5V increasing, and 32.4V
decreasing. The OVLO thresholds are approximately 77.7V
increasing, and 75.6V decreasing. The four thresholds are
determined by resistors R1-R4. The threshold voltage at each
pin is 2.50V, and internal 22 µA current sources provide hys-
teresis for each threshold. See the data sheet for more details.
Option A: This evaluation board is supplied with the jumper
at JMP1 on pins 2-3, resulting in the configuration shown in
Figure 5.
To change the thresholds in this configuration, resistors R1-
R3 are calculated using the following procedure:
- Choose the upper UVLO threshold (V
UVLO threshold (V
- Choose the upper OVLO threshold (V
- The lower OVLO threshold (V
vance in this case, but is determined after the values for R1-
R3 are determined. If V
addition to the other three thresholds, see Option B below.
The resistors are calculated as follows:
The lower OVLO threshold is calculated from:
FIGURE 5. UVLO, OVLO Inputs (Option A)
UVL
).
OVL
must be accurately defined in
OVL
) cannot be chosen in ad-
OVH
UVH
)
), and the lower
30038806
5
Option B: If all four thresholds must be determined accurate-
ly, move the jumper at JMP1 to pins 1-2, and add R4, resulting
in the configuration shown in Figure 6. See caution below.
The four resistor values are calculated as follows:
- Choose the upper and lower UVLO thresholds (V
(V
- Choose the upper and lower OVLO threshold (V
(V
CAUTION: Before moving the jumper at JMP1 to pins 1-2 for
Option B, the resistor values must be recalculated to avoid
damaging the LM5067. The Absolute Maximum Rating for the
OVLO and UVLO pins is 17V above VEE. If R4 is not installed,
the maximum rating for the UVLO pin will be reached when
Vin = -17V. With the supplied values for R2 and R3, the max-
imum rating for the OVLO pin will be reached when Vin =
-40V.
UVL
OVL
).
).
FIGURE 6. UVLO, OVLO Inputs (Option B)
www.national.com
OVH
30038811
UVH
) and
) and