LM5021NA-1/NOPB National Semiconductor, LM5021NA-1/NOPB Datasheet - Page 2

• Manufacturer Part Number: LM5021NA-1/NOPB
• Description: IC CTLR PWM AC-DC 8-MDIP
• Manufacturer: National Semiconductor

Specifications of LM5021NA-1/NOPB

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 1MHz
• Duty Cycle: 85%
• Voltage - Supply: 8 V ~ 30 V
• Buck: Yes
• Boost: Yes
• Flyback: Yes
• Inverting: Yes
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 8-DIP (0.300", 7.62mm)
• Frequency-max: 1MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM5021NA-1; *LM5021NA-1/NOPB; *LM5021NA-1NOPB; LM5021NA-1; LM5021NA-1NOPB; LM5021NA-1NOPB

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Connection Diagram
Ordering Information
Pin Descriptions
Pin
1
2
3
4
5
6
7
8
Order Number
LM5021MMX-1
LM5021MMX-2
LM5021MM-1
LM5021MM-2
LM5021NA-1
LM5021NA-2
RT / SYNC
COMP
Name
GND
VCC
OUT
VIN
CS
SS
Description
Control input for the Pulse Width Modulator
and Hiccup comparators.
Input voltage.
Output only of a linear bias supply regulator.
Nominally 8.5V.
MOSFET gate driver output.
Ground return.
Current Sense input.
Oscillator timing resistor pin and
synchronization input.
Soft-start / Hiccup time
80% Duty Cycle Limit
80% Duty Cycle Limit
80% Duty Cycle Limit
50% Duty Cycle Limit
50% Duty Cycle Limit
50% Duty Cycle Limit
Description
MSOP-8 and MDIP-8
Top View
2
Application Information
COMP pull-up is provided by an internal 5K resistor which
may be used to bias an opto-coupler transistor.
Input to start-up regulator. The VIN pin is clamped at 36V
by an internal zener diode.
VCC provides bias to controller and gate drive sections of
the LM5021. An external capacitor must be connected
from this pin to ground.
High current output to the external MOSFET gate input with
source/sink current capability of 0.3A and 0.7A
respectively.
Current sense input for current mode control and over-
current protection. Current limiting is accomplished using
a dedicated current sense comparator. If the CS
comparator input exceeds 0.5 Volts the OUT pin switches
low for cycle-by-cycle current limit. CS is held low for 90ns
after OUT switches high to blank the leading edge current
spike.
An external resistor connected from RT to GND sets the
oscillator frequency. This pin will also accept
synchronization pulses from an external clock.
An external capacitor and an internal 22 µA current source
set the soft-start ramp. The soft -start capacitor controls
both the soft-start rate and the hiccup mode period.
Package Type
MSOP-8
MSOP-8
MSOP-8
MSOP-8
MDIP-8
MDIP-8
20144202
1000 Units on Tape and Reel
3500 Units on Tape and Reel
40 Units per Rail
1000 Units on Tape and Reel
3500 Units on Tape and Reel
40 Units per Rail
Supplied As