IC, STEP-DOWN VOLTAGE REGULATOR, TO-220

LM2596T-ADJ

Manufacturer Part NumberLM2596T-ADJ
DescriptionIC, STEP-DOWN VOLTAGE REGULATOR, TO-220
ManufacturerNational Semiconductor
LM2596T-ADJ datasheet
 


Specifications of LM2596T-ADJ

Primary Input Voltage40VNo. Of Outputs1
Output Voltage37VOutput Current3A
No. Of Pins5Operating Temperature Range-40°C To +125°C
Supply Voltage Range4.5V To 40VFilter TerminalsThrough Hole
Rohs CompliantYesLead Free Status / RoHS StatusLead free / RoHS Compliant
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Application Information
This circuit has hysteresis
Regulator starts switching at V
= 13V
IN
Regulator stops switching at V
= 8V
IN
FIGURE 24. Undervoltage Lockout with Hysteresis for Inverting Regulator
C
— 68 µF/25V Tant. Sprague 595D
IN
470 µF/50V Elec. Panasonic HFQ
C
— 47 µF/20V Tant. Sprague 595D
OUT
220 µF/25V Elec. Panasonic HFQ
FIGURE 25. Inverting −5V Regulator with Delayed Startup
FIGURE 26. Inverting Regulator Typical Load Current
Because of differences in the operation of the inverting
regulator, the standard design procedure is not used to
select the inductor value. In the majority of designs, a 33 µH,
3.5A inductor is the best choice. Capacitor selection can also
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(Continued)
be narrowed down to just a few values. Using the values
shown in Figure 25 will provide good results in the majority of
inverting designs.
This type of inverting regulator can require relatively large
amounts of input current when starting up, even with light
loads. Input currents as high as the LM2596 current limit
(approx 4.5A) are needed for at least 2 ms or more, until the
output reaches its nominal output voltage. The actual time
depends on the output voltage and the size of the output
capacitor. Input power sources that are current limited or
sources that can not deliver these currents without getting
loaded down, may not work correctly. Because of the rela-
tively high startup currents required by the inverting topology,
the delayed startup feature (C1, R
25 is recommended. By delaying the regulator startup, the
input capacitor is allowed to charge up to a higher voltage
before the switcher begins operating. A portion of the high
01258341
input current needed for startup is now supplied by the input
capacitor (C
). For severe start up conditions, the input
IN
capacitor can be made much larger than normal.
26
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01258340
and R
) shown in Figure
1
2