National Semiconductor LM5022 Technical data
LM5022
60V Low Side Controller for Boost and SEPIC
LM5022 60V Low Side Controller for Boost and SEPIC
August 2007
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.
Typical Application
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
■
20212201
© 2007 National Semiconductor Corporation 202122 www.national.com
Connection Diagram
LM5022
NS Package Number MUB10A
10-Lead MSOP
20212253
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
LM5022MME MUB10A 250 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.
Inverting input to the internal voltage error amplifier. The non-
2 FB Feedback pin
3 COMP
4 VCC
5 OUT Output of MOSFET gate driver Connect this pin to the gate of the external MOSFET. The gate
6 GND System ground
7 UVLO Input Under-Voltage Lock-out
8 CS
9 RT/SYNC
10 SS Soft-start pin
Error amplifier output and PWM
comparator input
Output of the internal, high voltage linear
regulator.
Current Sense input Input for the switch current used for current mode control and for
Oscillator frequency adjust pin and
synchronization input
inverting input of the error amplifier connects to a 1.25V
reference.
The control loop compensation components connect between
this pin and the FB pin.
This pin should be bypassed to the GND pin with a ceramic
capacitor.
driver has a 1A peak current capability.
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.
current limiting.
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.
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
Electrical Characteristics Limits in standard type are for T
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
Junction Temperature Range -40°C to +125°C
= 25°C only; limits in boldface type apply over the
J
7.5V to 14V
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
≤ 125°C
J
1.225 1.250 1.275 V
START-UP REGULATOR
6.6 7 7.4
5
3.5 4
200
VCC
I
CC
I
CC-LIM
VIN - VCC
V
BYP-HI
V
BYP-HYS
Z
VCC
VCC
-HI
VCC
-HYS
I
VIN
I
IN-SD
VCC Regulation
VCC Regulation
Supply Current
9V ≤ VIN ≤ 60V, ICC = 1 mA
6V ≤ VIN < 9V, VCC Pin Open
Circuit
OUT Pin Capacitance = 0
VCC = 10V
VCC Current Limit VCC = 0V, (Note 4, 6) 15 35 mA
Dropout Voltage Across Bypass Switch
ICC = 0 mA, fSW < 200 kHz
6V ≤ VIN ≤ 8.5V
Bypass Switch Turn-off Threshold VIN increasing 8.7 V
Bypass Switch Threshold Hysteresis VIN Decreasing 260 mV
VCC Pin Output Impedance
0 mA ≤ ICC ≤ 5 mA
VIN = 6.0V 58
VIN = 8.0V 53
VIN = 24.0V 1.6
VCC Pin UVLO Rising Threshold 5 V
VCC Pin UVLO Falling Hysteresis 300 mV
Start-up Regulator Leakage VIN = 60V 150 500 µA
Shutdown Current V
= 0V, VCC = Open Circuit 350 450 µA
UVLO
ERROR AMPLIFIER
GBW Gain Bandwidth 4 MHz
A
I
COMP
DC
DC Gain 75 dB
COMP Pin Current Sink Capability
VFB = 1.5V
V
= 1V
COMP
5 17
UVLO
V
SD
I
SD-HYS
Shutdown Threshold 1.22 1.25 1.28 V
Shutdown
16 20 24
Hysteresis Current Source
CURRENT LIMIT
t
LIM-DLY
V
CS
t
BLK
R
CS
Delay from ILIM to Output
CS steps from 0V to 0.6V
OUT transitions to 90% of VCC
Current Limit Threshold Voltage 0.45 0.5 0.55 V
Leading Edge Blanking Time 65 ns
CS Pin Sink Impedance Blanking active 40 75
30
V
mA
mV
Ω
mA
µA
ns
Ω
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Symbol Parameter Conditions Min Typ Max Units
SOFT-START
LM5022
V
SS-OFF
I
SS
Soft-start Current Source 7 10 13 µA
Soft-start to COMP Offset 0.35 0.55 0.75 V
OSCILLATOR
(Note 5) 170 200 230 kHz
(Note 5) 525 600 675 kHz
(Note 5) 865 990 1115 kHz
f
V
SYNC-HI
SW
RT to GND = 84.5 kΩ
RT to GND = 27.4 kΩ
RT to GND = 16.2 kΩ
Synchronization Rising Threshold 3.8 V
PWM COMPARATOR
t
COMP-DLY
D
MIN
D
MAX
A
PWM
V
COMP-OC
I
COMP-SC
= 2V
Delay from COMP to OUT Transition
Minimum Duty Cycle V
COMP
CS stepped from 0V to 0.4V
= 0V 0 %
COMP
Maximum Duty Cycle 90 95 %
COMP to PWM Comparator Gain 0.33 V/V
COMP Pin Open Circuit Voltage VFB = 0V 4.3 5.2 6.1 V
COMP Pin Short Circuit Current V
= 0V, VFB = 1.5V 0.6 1.1 1.5 mA
COMP
25
V
SLOPE COMPENSATION
V
SLOPE
Slope Compensation Amplitude 80 105 130 mV
MOSFET DRIVER
V
SAT-HI
Output High Saturation Voltage (VCC –
I
= 50 mA 0.25 0.75 V
OUT
VOUT)
V
SAT-LO
t
RISE
t
FALL
Output Low Saturation Voltage (VOUT) I
= 100 mA 0.25 0.75 V
OUT
OUT Pin Rise Time OUT Pin load = 1 nF 18 ns
OUT Pin Fall Time OUT Pin load = 1 nF 15 ns
THERMAL CHARACTERISTICS
T
SD
T
SD-HYS
θ
JA
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.
Thermal Shutdown Threshold 165 °C
Thermal Shutdown Hysteresis 25 °C
Junction to Ambient Thermal Resistance MUB-10A Package 200 °C/W
ns
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Typical Performance Characteristics
LM5022
Efficiency, VO = 40V
Example Circuit BOM
VFB vs. VIN (TA = 25°C)
VFB vs. Temp (VIN = 24V)
20212203
20212255
VCC vs. VIN (TA = 25°C)
Max Duty Cycle vs. fSW (TA = 25°C)
20212204
20212206
20212205
fSW vs. Temperature (RT = 16.2 kΩ)
20212207
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LM5022
RT vs. fSW (TA = 25°C)
SS vs. Temperature
OUT Pin t
vs. Gate Capacitance
RISE
20212208
20212210
OUT Pin t
vs. Gate Capacitance
FALL
20212209
20212211
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Block Diagram
LM5022
20212212
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