LM5060EVAL Datasheet, PDF (1/6 Pages) National Semiconductor (TI) – Evaluation Board Output Current Range: 0A to 5.0A

LM5060EVAL Evaluation
Board
National Semiconductor
Application Note 2000
Frederik Dostal
October 26, 2010
Introduction
The LM5060 evaluation board is designed to demonstrate the
capabilities of the LM5060 high side protection controller with
low quiescent current. It is intended for evaluation of the func-
tions of the LM5060. One high side N-channel power MOS-
FET is used. The LM5060 evaluation board schematic is
shown in Figure 7. The evaluation board is designed to high-
light applications with a small solution size. For more infor-
mation about LM5060 functional and electrical characteris-
tics, refer to the LM5060 datasheet.
Operating Range
• Maximum Input Voltage, OVP: 37V
• Minimum Input Voltage, UVLO: 9V
• Output Current Range: 0A to 5.0A
• Ambient Temperature Range 0°C to 50°C
• Board Size 1.35in x 2.25in
To aid in the design and evaluation of high-side protection
controller solutions based on the LM5060, the evaluation
board can be re-configured for different input voltage ranges
by modifying the UVLO and the OVP resistive divider (R1, R2,
and R3) as well as the protection transient voltage suppressor
diode D1.
The load current capability may be increased above 5A of by
changing the value of resistor R4. The PCB layout has not
been tested for currents above 5A, so this should only be done
with some degree of caution.
Typical evaluation board performance and characteristics
curves are shown in Figure 1 through Figure 5. The PCB lay-
out is shown in Figure 9 and Figure 10. Test points are
provided to enable easy connection and monitoring of critical
signals.
Evaluation Board Start-Up
Before applying power to the LM5060 evaluation board, all
external connections should be verified. The external power
supply must be turned off and connected with proper polarity
to the INPUT and GND posts. A load resistor should be con-
nected between the OUTPUT and GND posts as desired. A
resistive load will keep the current through Q1 during turn-on
relatively low. Electronic load equipment tends to be very low
impedance during voltage rise so that the transistor Q1 will
see very high currents during turn-on when using such loads.
Though resistive loads are suggested for use with the
LM5060 evaluation board, electronic loads can be used with
caution as well. The output voltage can be monitored with a
multi-meter or oscilloscope at the OUTPUT post.
Once all connections to the evaluation board have been ver-
ified, input power can be applied. A load resistor or electronic
load does not require connection during startup. If the EN test
point is pulled high (see the threshold voltage in the electrical
characteristics section of the LM5060 datasheet), the output
voltage will ramp up when an input voltage is applied.
For the evaluation board to start up, the EN pin needs to be
pulled high. A lab cable is required from the EN pin to the VIN
pin or other voltage source higher than 2.0V.
Make sure that the external power supply (input voltage pow-
er source) is capable of providing enough current to the output
load so that the output voltage can be obtained.
30104712
FIGURE 1. Start-Up Waveforms
30104713
FIGURE 2. Start-Up Waveforms
Inductive Kick-Back Protection
Diode D1 and capacitor C4 serve as inductive kick protection
to limit voltage spikes generated when shutting down high
currents through Q1 when turning the power MOSFET off.
Capacitor C5 is useful for preventing negative voltages on the
OUTPUT trace as the MOSFET Q1 is turned off.
Enable
The EN test point provided on the LM5060 evaluation board
is used to control the LM5060 operation. To shut down the
LM5060 evaluation board apply a voltage less than 0.8V to
the EN pin, connect to ground, or open the connection. To
start up the LM5060 evaluation board apply a voltage greater
© 2010 National Semiconductor Corporation 301047
www.national.com