Datasheet

LM2595
www.ti.com SNVS122B –MAY 1999–REVISED APRIL 2013
Without diode D3, when the input voltage is first applied, the charging current of C
IN
can pull the output positive
by several volts for a short period of time. Adding D3 prevents the output from going positive by more than a
diode voltage.
This circuit has hysteresis
Regulator starts switching at V
IN
= 13V
Regulator stops switching at V
IN
= 8V
Figure 37. Undervoltage Lockout with Hysteresis for Inverting Regulator
C
IN
: — 220 μF/25V Tant. Sprague 595D
120 μF/50V Elec. Panasonic HFQ
C
OUT
: — 22 μF/20V Tant. Sprague 595D
120 μF/25V Elec. Panasonic HFQ
Figure 38. Inverting −5V Regulator with Delayed Startup
Figure 39. 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 68 μH, 1.5A inductor is the best choice. Capacitor
selection can also be narrowed down to just a few values. Using the values shown in Figure 38 will provide good
results in the majority of inverting designs.
Copyright © 1999–2013, Texas Instruments Incorporated Submit Documentation Feedback 29
Product Folder Links: LM2595