LM5000
LM5000 High Voltage Switch Mode Regulator
Literature Number: SNVS176D
February 2007 LM5000
High Voltage Switch Mode Regulator
General Description
The LM5000 is a monolithic integrated circuit specifically de-signed and optimized for flyback, boost or forward power converter applications. The internal power switch is rated for a maximum of 80V, with a current limit set to 2A. Protecting the power switch are current limit and thermal shutdown cir-cuits. The current mode control scheme provides excellent rejection of line transients and cycle-by-cycle current limiting. An external compensation pin and the built-in slope compen-sation allow the user to optimize t
he frequency compensation. Other distinctive features include softstart to reduce stresses during start-up and an external shutdown pin for remote ON/ OFF control. There are two operating frequency ranges avail-able. The LM5000-3 is pin selectable for either 300kHz (FS Grounded) or 700kHz (FS Open). The LM5000-6 is pin se-lectable for either 600kH z (FS Grounded) or 1.3MH z (FS Open). The device is available in a low profile 16-lead TSSOP package or a thermally enhanced 16-lead LLP package.Features
■80V internal switch
■Operating input voltage range of 3.1V to 40V
■Pin selectable operating frequency
300kHz/700kHz (-3)
600kHz/1.3MHz (-6)
■Adjustable output voltage
■External compensation
■Input undervoltage lockout
■Softstart
■Current limit
■Over temperature protection
■External shutdown
■Small 16-Lead TSSOP or 16-Lead LLP package Applications
■Flyback Regulator
■Forward Regulator
■Boost Regulator
■DSL Modems
■Distributed Power Converters
Typical Application Circuit
20031901
LM5000 Flyback Converter
© 2007 National Semiconductor LM5000 High Voltage Switch Mode Regulator
Connection Diagram
Top View
20031904
Ordering Information
Order Number Package Type NSC Package Drawing
Supplied As
LM5000-3MTC TSSOP-16MTC1694 Units, Rail
LM5000-3MTCX TSSOP-16MTC162500 Units, Tape and Reel LM5000SD-3LLP-16SDA161000 Units, Rail
LM5000SDX-3LLP-16SDA164500 Units, Tape and Reel LM5000SD-6LLP-16SDA161000 Units, Rail
LM5000SDX-6
LLP-16
SDA16
4500 Units, Tape and Reel
Pin Descriptions
Pin Name Function
1
COMP
Compensation network connection. Connected to the output of the voltage error amplifier. The RC compenstion network should be connected from this pin to AGND. An additional 100pF high frequency capacitor to AGND is recommended.2FB Output voltage feedback input.
3SHDN Shutdown control input, Open = enable, Ground = disable.4AGND Analog ground, connect directly to PGND.5PGND Power ground.6PGND Power ground.7PGND Power ground.8PGND Power ground.
9SW Power switch input. Switch connected between SW pins and PGND pins 10SW Power switch input. Switch connected between SW pins and PGND pins 11SW Power switch input. Switch connected between SW pins and PGND pins 12BYP Bypass-Decouple Capacitor Connection, 0.1µF ceramic capacitor recommended.
13
V IN
Analog power input. A small RC filter is recommended, to suppress line glitches. Typical values of 10Ω and ≥ 0.1µF are recommended.
14SS Softstart Input. External capacitor and internal current source sets the softstart time.15FS Switching frequency select input. Open = F high . Ground = F low 16TEST Factory test pin, connect to ground.
-Exposed Pad underside of LLP
package
Connect to system ground plane for reduced thermal resistance.
2
L M 5000
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.V IN
-0.3V to 40V SW Voltage -0.3V to 80V FB Voltage -0.3V to 5V COMP Voltage -0.3V to 3V All Other Pins
-0.3V to 7V
Maximum Junction Temperature 150°C
Power Dissipation(Note 2)Internally Limited
Lead Temperature
216°C
Infrared (15 sec.)
235°C
ESD Susceptibility (Note 3) Human Body Model 2kV Machine Model 200V
Storage Temperature −65°C to +150°C
Operating Conditions
Operating Junction Temperature Range (Note 7)
−40°C to +125°C
Supply Voltage (Note 7)
3.1V to 40V
Electrical Characteristics
Specifications in standard type face are for T J = 25°C and those with boldface type apply over the full Operating Temperature Range (T J = −40°C to +125°C) Unless otherwise specified. V IN = 12V and I L = 0A, unless otherwise specified.Symbol Parameter
Conditions
Min (Note 4)
Typ (Note 5)Max (Note 4)Units I Q
Quiescent Current
FB = 2V (Not Switching)FS = 0V
2.0 2.5mA FB = 2V (Not Switching)FS = Open 2.1 2.5mA V SHDN = 0V
1830µA V FB Feedback Voltage 1.2330 1.259 1.2840V I CL
Switch Current Limit
1.35
2.0 2.7A %V FB /ΔV IN Feedback Voltage Line Regulation
3.1V ≤ V IN ≤ 40V
0.0010.04%/V I B FB Pin Bias Current (Note 6)
55200
nA BV
Output Switch Breakdown Voltage
T J = 25°C, I SW = 0.1µA 80
V
T J = -40°C to + 125°C, I SW =0.5µA 76
V IN Input Voltage Range 3.1 40V g m Error Amp Transconductance ΔI = 5µA
150
410750µmho A V Error Amp Voltage Gain
280 V/V D MAX
Maximum Duty Cycle LM5000-3
FS = 0V 8590 %Maximum Duty Cycle LM5000-6
FS = 0V 8590 %T MIN Minimum On Time 165 ns f S Switching Frequency LM5000-3
FS = 0V 240300360kHz FS = Open 550700840 Switching Frequency LM5000-6
FS = 0V 485600715 FS = Open 1.055 1.3 1.545MHz I SHDN Shutdown Pin Current V SHDN = 0V −1-2µA I L Switch Leakage Current V SW = 80V 0.0085µA R DSON Switch R DSON I SW = 1A
160445m ΩTh SHDN SHDN Threshold Output High 0.90.6 V Output Low
0.60.3V UVLO On Threshold 2.74 2.92 3.10V Off Threshold 2.60 2. 77 2.96
V OVP V COMP Trip
0.67
V I SS
Softstart Current
811
14
µA
LM5000
Symbol Parameter
Conditions
Min (Note 4)
Typ (Note 5)Max (Note 4)
Units θJA
Thermal Resistance
TSSOP, Package only 150 °C/W
LLP, Package only
45
Note 1:Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended to be functional, but device parameter specifications may not be guaranteed. For guaranteed specifications and test conditions, see the Electrical Characteristics.Note 2:The maximum allowable power dissipation is a function of the maximum junction temperature, T J (MAX), the junction-to-ambient thermal resistance,θJA , and the ambient temperature, T A . See the Electrical Characteristics table for the thermal resistance of various layouts. The maximum allowable power dissipation at any ambient temperature is calculated using: P D (MAX) = (T J(MAX) − T A )/θJA . Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown.
Note 3:The human body model is a 100 pF capacitor discharged through a 1.5k Ω resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin.
Note 4:All limits guaranteed at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are 100%
production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
Note 5:Typical numbers are at 25°C and represent the most likely norm.Note 6:Bias current flows into FB pin.
Note 7:Supply voltage, bias current product will result in aditional device power dissipation. This power may be significant. The thermal dissipation design should take this into account.
4
L M 5000
