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

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LM25061MM-2EVAL/NOPB

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

Specifications of LM25061MM-2EVAL/NOPB

Lead Free Status / RoHS Status
Lead free / RoHS Compliant
© 2009 National Semiconductor Corporation
LM25061 Evaluation Board
Introduction
The LM25061EVAL evaluation board provides the design en-
gineer with a fully functional hot swap controller board de-
signed for positive voltage systems. This board contains an
LM25061-2, the auto restart version of this IC. This applica-
tion note describes the various functions of the board, how to
test & evaluate it, and how to change the components for a
specific application. The LM25061 data sheet is available
from www.national.com.
The board’s specifications are:
Board Configuration
A pictorial of the LM25061 evaluation board is shown in Figure
1, and the schematic is shown in Figure 2. The “BACKPLANE”
section, at the left end of the board, represents the backplane
voltage source. The vertical dashed line is the boundary be-
tween the backplane voltage source and the hot swap circuit
input. In other words, it represents the edge connector in a
card cage system. The toggle switch (SW1) provides a means
to “connect” and “disconnect” the hot swap circuit from the
backplane voltage source. The circuitry to the right of the ver-
tical dashed line is the hot swap circuit. The system voltage
is to be connected to the input terminal block (J1). The exter-
nal load is to be connected to the output terminal block (J2).
Capacitors C3 and C4 represent capacitance which is typi-
300914
FIGURE 1. Evaluation Board - Top Side
National Semiconductor
Application Note 1946
Dennis Morgan
June 29, 2009
cally present on the input of the load circuit, and are present
on this evaluation board so the turn-on characteristics of the
LM25061 may be tested without having to connect a load.
For a hot swap circuit to function reliably, capacitance is
needed on the supply side of the system connector (C7). Its
purpose is to minimize voltage transients which occur when-
ever the load current changes or is shut off. If the capacitance
is not present, wiring inductance in the supply lines generate
a voltage transient at shutoff which can exceed the absolute
maximum rating of the LM25061, resulting in its destruction.
The LM25061EVB is supplied with pins 1-2 jumpered on
JMP2.
Input voltage range: +2.9V to 17V
Current limit: 5 Amps, ±10%
Q1 Power limit: 15W
UVLO Thresholds: 4.7V and 4.45V
PGD Thresholds: 13V and 12.5V
Insertion delay: 213 ms
Fault timeout period: 14.6 ms and 12.1 ms
Restart time: 1.8 seconds
Size: 4.0” x 1.38”
www.national.com
30091401

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LM25061MM-2EVAL/NOPB Summary of contents

Page 1

... The system voltage connected to the input terminal block (J1). The exter- nal load connected to the output terminal block (J2). Capacitors C3 and C4 represent capacitance which is typi- © 2009 National Semiconductor Corporation National Semiconductor Application Note 1946 Dennis Morgan June 29, 2009 • ...

Page 2

Theory of Operation The LM25061 provides intelligent control of the power supply connections of a load which connected to a live power source. The two primary functions of a hot swap circuit are in- rush current limiting ...

Page 3

The UVLO thresholds are set by resistors R1 and R2 and the PGD thresholds are set by resistors R3 and R4. Internal cur- FIGURE 3. Power Up Using Power Limit and Current Limit Board Layout and Probing Cautions The pictorial ...

Page 4

Circuit Parameter Changes CURRENT LIMIT The current limit threshold is set by R10 according to the fol- lowing equation mV/R10 LIM If the load current increases such that the voltage across R10 reaches 50 mV, the LM25061 ...

Page 5

UVLO Input Voltage Threshold Programming the UVLO thresholds sets the minimum system voltage to enable the series pass device (Q1 the UVLO thresholds switched off, denying power to the load. Programmable hysteresis is provided. OPTION A ...

Page 6

... The companion Hot-Swap IC, the LM25061-1, latches off af- ter a fault detection, with external control required for restart. Restart is accomplished by momentarily taking the UVLO pin below its threshold removing and re-applying the input voltage at VIN. Contact the nearest National Semiconductor sales office to obtain samples of the LM25061-1. 6 30091416 µ ...

Page 7

Performance Characteristics Horizontal Resolution: 100 ms/div Trace 10V/div IN Trace 2: TIMER Pin, 1V/div Trace 10V/div OUT V = 12V 0.68 µ FIGURE 8. Insertion Time Delay Horizontal Resolution: 1 ...

Page 8

Horizontal Resolution: 2 ms/div Trace 2: TIMER Pin, 1V/div Trace 10V/div OUT Trace 4: Input Current, 2A/div V = 14V, Load = 3Ω 0.68 µ FIGURE 12. Restart Fault Timeout www.national.com 30091421 Horizontal ...

Page 9

... Fairchild FDD8874 Vishay CRCW120614K0F Vishay CRCW08054K99F Vishay CRCW080523K2F Vishay CRCW08052K26F Vishay CRCW1206100KF Vishay CRCW08050000Z Vishay CRCW080534K8F Vishay WSL2010R0100F NKK M2012SS1W03-RO Nat’l Semi LM25061MM-2 Diodes Inc. SMBJ16A 9 Package Value 0805 1000 pF, 100V Surf. Mount 220 µF, 35V 1206 0.1 µF, 100V Surf. Mount 100 µ ...

Page 10

PC Board Layout www.national.com Board Silkscreen Board Top Layer Board Bottom Layer (viewed from top) 10 30091424 30091425 30091426 ...

Page 11

Notes 11 www.national.com ...

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