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Número de pieza | LM2841 | |
Descripción | (LM2841 / LM28420) 300 MA/600 MA Up To 42V Input Step-Down DC/DC Regulator | |
Fabricantes | National Semiconductor Corporation | |
Logotipo | ||
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LM2841
LM2842
April 2, 2009
300 mA/600 mA up to 42V Input Step-Down DC/DC
Regulator in Thin SOT-23
General Description
The LM2841 and LM2842 are PWM DC/DC buck (step-down)
regulators. With a wide input range from 4.5V-42V, they are
suitable for a wide range of applications such as power con-
ditioning from unregulated sources. They feature a low
RDSON (0.9Ω typical) internal switch for maximum efficiency
(85% typical). Operating frequency is fixed at 550 kHz (X ver-
sion) and 1.25 MHz (Y version) allowing the use of small
external components while still being able to have low output
voltage ripple. Soft-start can be implemented using the shut-
down pin with an external RC circuit allowing the user to tailor
the soft-start time to a specific application.
The LM2842 is optimized for up to 600 mA load currents while
the LM2841 is optimized for up to 300 mA load current. Both
have a 0.765V nominal feedback voltage.
Additional features include: thermal shutdown, VIN under-volt-
age lockout, and gate drive under-voltage lockout. The
LM2841 and LM2842 are available in a low profile TSOT-6L
package.
Features
■ Input voltage range of 4.5V to 42V
■ Output current options of 300 mA and 600 mA
■ Feedback pin voltage of 0.765V
■ 550 kHz (X) or 1.25 Mhz (Y) switching frequency
■ Low shutdown IQ, 16 µA typical
■ Short circuit protected
■ Internally compensated
■ Soft-start circuitry
■ Small overall solution size (TSOT-6L package)
Applications
■ Battery powered equipment
■ Industrial distributed power applications
■ Portable media players
■ Portable hand held instruments
Typical Application Circuit
30036702
© 2009 National Semiconductor Corporation 300367
www.national.com
1 page 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
wwtowb.eDfuantactSiohneale, tb4uUt d.cevoimce 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, TJ(MAX), the junction-to-ambient thermal resistance,
θJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD (MAX) = (TJ(MAX) − TA)/
θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal
shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=175°C (typ.) and disengages at TJ=155°C (typ).
Note 3: Human Body Model, applicable std. JESD22-A114-C.
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: Includes the bond wires, RDSON from VIN pin to SW pin.
Note 7: Current limit at 0% duty cycle.
Note 8: Bias currents flow into pin.
Note 9: All numbers apply for packages soldered directly onto a 3" x 3" PC board with 2 oz. copper on 4 layers in still air in accordance to JEDEC standards.
Thermal resistance varies greatly with layout, copper thickness, number of layers in PCB, power distribution, number of thermal vias, board size, ambient
temperature, and air flow.
5 www.national.com
5 Page www.DataSheet4U.com
FIGURE 3. Application Circuit, 12V Output
30036709
FIGURE 4. Application Circuit, 15V Output
30036716
FIGURE 5. Application Circuit, 0.8V Output
30036717
11 www.national.com
11 Page |
Páginas | Total 14 Páginas | |
PDF Descargar | [ Datasheet LM2841.PDF ] |
Número de pieza | Descripción | Fabricantes |
LM2841 | LM2840/41/42/40Q/41Q/42Q 100/300/600 mA Input Step-Down DC/DC Reg in Thin SOT-23 (Rev. H) | Texas Instruments |
LM2841 | (LM2841 / LM28420) 300 MA/600 MA Up To 42V Input Step-Down DC/DC Regulator | National Semiconductor Corporation |
LM2842 | LM2840/41/42/40Q/41Q/42Q 100/300/600 mA Input Step-Down DC/DC Reg in Thin SOT-23 (Rev. H) | Texas Instruments |
LM2842 | (LM2841 / LM28420) 300 MA/600 MA Up To 42V Input Step-Down DC/DC Regulator | National Semiconductor Corporation |
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