NSC LM5022MM, LM5022 Datasheet

January 2007

LM5022
60V Low Side Controller for Boost and SEPIC

General Description

The LM5022 is a high voltage low-side N-channel MOSFET
controller ideal for use in boost and SEPIC regulators. It con­tains all of the features needed to implement single ended
primary topologies. Output voltage regulation is based on
current-mode control, which eases the design of loop com­pensation while providing inherent input voltage feed-forward.
The LM5022 includes a start-up regulator that operates over
a wide input range of 6V to 60V. The PWM controller is de­signed for high speed capability including an oscillator fre­quency range up to 2 MHz and total propagation delays less
than 100 ns. Additional features include an error amplifier,
precision reference, line under-voltage lockout, cycle-by-cy­cle current limit, slope compensation, soft-start, external syn­chronization capability and thermal shutdown. The LM5022 is
available in the MSOP-10 package.

Features

■

Internal 60V Startup Regulator

■

1A Peak MOSFET Gate Driver

■

VIN Range 6V to 60V

■

Duty Cycle Limit of 90%

■

Programmable UVLO with Hysteresis

■

Cycle-by-Cycle Current Limit

■

External Synchronizable (AC-coupled)

■

Single Resistor Oscillator Frequency Set

■

Slope Compensation

■

Adjustable Soft-start

■

MSOP-10 Package

Applications

■

Boost Converter

■

SEPIC Converter

Typical Application

20212201

© 2007 National Semiconductor Corporation 202122 www.national.com

LM5022 60V Low Side Controller for Boost and SEPIC

Connection Diagram

20212253

10-Lead MSOP

NS Package Number MUB10A

Ordering Information

Part Number NS Package Drawing Supplied As

LM5022MM MUB10A 1000 Units on Tape and Reel

LM5022MMX MUB10A 3500 Units on Tape and Reel

Pin Descriptions

Pin(s) Name Description Application Information

1 VIN Source input voltage Input to the start-up regulator. Operates from 6V to 60V.

2 FB Feedback pin

Inverting input to the internal voltage error amplifier. The non­inverting input of the error amplifier connects to a 1.25V
reference.

3 COMP

Error amplifier output and PWM
comparator input

The control loop compensation components connect between
this pin and the FB pin.

4 VCC

Output of the internal, high voltage linear
regulator.

This pin should be bypassed to the GND pin with a ceramic
capacitor.

5 OUT Output of MOSFET gate driver Connect this pin to the gate of the external MOSFET. The gate

driver has a 1A peak current capability.

6 GND System ground

7 UVLO Input Under-Voltage Lock-out

Set the start-up and shutdown levels by connecting this pin to the
input voltage through a resistor divider. A 20 µA current source
provides hysteresis.

8 CS

Current Sense input Input for the switch current used for current mode control and for

current limiting.

9 RT/SYNC

Oscillator frequency adjust pin and
synchronization input

An external resistor connected from this pin to GND sets the
oscillator frequency. This pin can also accept an AC-coupled
input for synchronization from an external clock.

10 SS Soft-start pin

An external capacitor placed from this pin to ground will be
charged by a 10 µA current source, creating a ramp voltage to
control the regulator start-up.

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LM5022

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

VIN to GND -0.3V to 65V
VCC to GND -0.3V to 16V
RT/SYNC to GND -0.3V to 5.5V
OUT to GND -1.5V for < 100 ns
All other pins to GND -0.3V to 7V
Power Dissipation Internally Limited
Junction Temperature 150°C

Storage Temperature -65°C to +150°C
Soldering Information
Vapor Phase (60 sec.) 215°C
Infrared (15 sec.) 220°C
ESD Rating
Human Body Model (Note 2) 2 kV

Operating Ranges (Note 4)

Supply Voltage 6V to 60V
External Volatge at V

CC

7.5V to 14V

Junction Temperature Range -40°C to +125°C

Electrical Characteristics Limits in standard type are for T

J

= 25°C only; limits in boldface type apply over the
junction temperature (TJ) range of -40°C to +125°C. Minimum and Maximum limits are guaranteed through test, design, or statistical
correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only.
VIN = 24V and RT = 27.4 kΩ unless otherwise indicated. (Note 3)

Symbol Parameter Conditions Min Typ Max Units

SYSTEM PARAMETERS

V

FB

FB Pin Voltage

-40°C ≤ T

J

≤ 125°C

1.225 1.250 1.275 V

START-UP REGULATOR

VCC

VCC Regulation

9V ≤ VIN ≤ 60V, ICC = 1 mA

6.6 7 7.4

V

VCC Regulation

6V ≤ VIN < 9V, VCC Pin Open
Circuit

5

I

CC

Supply Current

OUT Pin Capacitance = 0
VCC = 10V

3.5 4
mA

I

CC-LIM

VCC Current Limit VCC = 0V, (Note 4, 6) 15 35 mA

VIN - VCC

Dropout Voltage Across Bypass Switch

ICC = 0 mA, fSW < 200 kHz
6V ≤ VIN ≤ 8.5V

200

mV

V

BYP-HI

Bypass Switch Turn-off Threshold VIN increasing 8.7 V

V

BYP-HYS

Bypass Switch Threshold Hysteresis VIN Decreasing 260 mV

Z

VCC

VCC Pin Output Impedance
0 mA ≤ ICC ≤ 5 mA

VIN = 6.0V 58

Ω

VIN = 8.0V 53

VIN = 24.0V 1.6

VCC

-HI

VCC Pin UVLO Rising Threshold 5 V

VCC

-HYS

VCC Pin UVLO Falling Hysteresis 300 mV

I

VIN

Start-up Regulator Leakage VIN = 60V 150 500 µA

I

IN-SD

Shutdown Current V

UVLO

= 0V, VCC = Open Circuit 350 450 µA

ERROR AMPLIFIER

GBW Gain Bandwidth 4 MHz

A

DC

DC Gain 75 dB

I

COMP

COMP Pin Current Sink Capability

VFB = 1.5V
V

COMP

= 1V

5 17

mA

UVLO

V

SD

Shutdown Threshold 1.22 1.25 1.28 V

I

SD-HYS

Shutdown
Hysteresis Current Source

16 20 24

µA

CURRENT LIMIT

t

LIM-DLY

Delay from ILIM to Output

CS steps from 0V to 0.6V
OUT transitions to 90% of VCC

30

ns

V

CS

Current Limit Threshold Voltage 0.45 0.5 0.55 V

t

BLK

Leading Edge Blanking Time 65 ns

R

CS

CS Pin Sink Impedance Blanking active 40 75

Ω

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LM5022

Symbol Parameter Conditions Min Typ Max Units

SOFT-START

I

SS

Soft-start Current Source 7 10 13 µA

V

SS-OFF

Soft-start to COMP Offset 0.35 0.55 0.75 V

OSCILLATOR

f

SW

RT to GND = 84.5 kΩ

(Note 5) 170 200 230 kHz

RT to GND = 27.4 kΩ

(Note 5) 525 600 675 kHz

RT to GND = 16.2 kΩ

(Note 5) 865 990 1115 kHz

V

SYNC-HI

Synchronization Rising Threshold 3.8 V

PWM COMPARATOR

t

COMP-DLY

Delay from COMP to OUT Transition

V

COMP

= 2V

CS stepped from 0V to 0.4V

25

ns

D

MIN

Minimum Duty Cycle V

COMP

= 0V 0 %

D

MAX

Maximum Duty Cycle 90 95 %

A

PWM

COMP to PWM Comparator Gain 0.33 V/V

V

COMP-OC

COMP Pin Open Circuit Voltage VFB = 0V 4.3 5.2 6.1 V

I

COMP-SC

COMP Pin Short Circuit Current V

COMP

= 0V, VFB = 1.5V 0.6 1.1 1.5 mA

SLOPE COMPENSATION

V

SLOPE

Slope Compensation Amplitude 80 105 130 mV

MOSFET DRIVER

V

SAT-HI

Output High Saturation Voltage (VCC –
VOUT)

I

OUT

= 50 mA 0.25 0.75 V

V

SAT-LO

Output Low Saturation Voltage (VOUT) I

OUT

= 100 mA 0.25 0.75 V

t

RISE

OUT Pin Rise Time OUT Pin load = 1 nF 18 ns

t

FALL

OUT Pin Fall Time OUT Pin load = 1 nF 15 ns

THERMAL CHARACTERISTICS

T

SD

Thermal Shutdown Threshold 165 °C

T

SD-HYS

Thermal Shutdown Hysteresis 25 °C

θ

JA

Junction to Ambient Thermal Resistance MUB-10A Package 200 °C/W

Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. The Recommended Operating Limits define the conditions within
which the device is intended to be functional. For guaranteed specifications and test conditions, see the Electrical Characteristics.

Note 2: The human body model is a 100 pF capacitor discharged through a 1.5kΩ resistor into each pin.

Note 3: Min and Max limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical

Quality Control (SQC) methods. Limits are used to calculate National’s Average Outgoing Quality Level (AOQL).

Note 4: Device thermal limitations may limit usable range.

Note 5: Specification applies to the oscillator frequency.

Note 6: VCC provides bias for the internal gate drive and control circuits.

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LM5022

Typical Performance Characteristics

Efficiency, VO = 40V

Example Circuit BOM

20212255

VFB vs. Temp (VIN = 24V)

20212203

VFB vs. VIN (TA = 25°C)

20212204

VCC vs. VIN (TA = 25°C)

20212205

Max Duty Cycle vs. fSW (TA = 25°C)

20212206

fSW vs. Temperature (RT = 16.2 kΩ)

20212207

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LM5022

RT vs. fSW (TA = 25°C)

20212208

SS vs. Temperature

20212209

OUT Pin t

RISE

vs. Gate Capacitance

20212210

OUT Pin t

FALL

vs. Gate Capacitance

20212211

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LM5022

Block Diagram

20212212

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LM5022