LM5020EVAL National Semiconductor, LM5020EVAL Datasheet - Page 3
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LM5020EVAL
Manufacturer Part Number
LM5020EVAL
Description
EVALUATION BOARD FOR LM5020
Manufacturer
National Semiconductor
Series
PowerWise®r
Specifications of LM5020EVAL
Main Purpose
DC/DC, Step Down
Outputs And Type
1, Isolated
Voltage - Output
3.3V
Current - Output
4.5A
Voltage - Input
30 ~ 75V
Regulator Topology
Buck
Board Type
Fully Populated
Utilized Ic / Part
LM5020
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Power - Output
-
Frequency - Switching
-
Other names
*LM5020EVAL
Pin Descriptions
Pin
10
1
2
3
4
5
6
7
8
9
RT / SYNC
COMP
Name
UVLO
VCC
OUT
GND
VIN
FB
CS
SS
Source Input Voltage
Feedback Signal
The output of the error amplifier and input to
the Pulse Width Modulator
Output of the internal high voltage series pass
regulator. Regulated output voltage is 7.7V
Output of the PWM controller
Ground return
Line Under-Voltage Shutdown
Current Sense input
Oscillator timing resistor pin and
synchronization input
Softstart Input
Description
3
Input to the start-up regulator. Input range is 13V to
100V.
Inverting input of the internal error amplifier. The
non-inverting input is internally connected to a 1.25V
reference.
COMP pull-up is provided by an internal 5K resistor
which may be used to bias an opto-coupler transistor.
If an auxiliary winding raises the voltage on this pin
above the regulation set point, the internal series pass
regulator will shut down, reducing the internal power
dissipation.
Gate driver output with a 1A peak current capability.
An external resistor divider from the power converter
source voltage sets the shutdown levels. The threshold
at this pin is 1.25V. Hysteresis is set by a switched
internal 20µA current source.
Current sense input for current mode control and
over-current protection. Current limiting is accomplished
using a dedicated current sense comparator. If the CS
pin voltage exceeds 0.5V the OUT pin switches low for
cycle-by-cycle current limiting. CS is held low for 50ns
after OUT switches high to blank leading edge current
spikes.
An external resistor connected from RT to GND sets the
oscillator frequency. This pin also accepts
synchronization pulses from an external clock.
An external capacitor and an internal 10µA current
source set the soft-start ramp rate.
Application Information
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