Datasheet

LP3991
www.ti.com SNVS296H –DECEMBER 2006–REVISED MAY 2013
Electrical Characteristics
(1)
(continued)
Unless otherwise noted, V
EN
= 950mV, V
IN
= V
OUT
+ 0.5V, or 1.8V, whichever is higher. C
IN
= 1µF, I
OUT
= 1.0mA, C
OUT
=
4.7µF. Typical values and limits appearing in normal type apply for T
A
= 25°C. Limits appearing in boldface type apply over
the full junction temperature range for operation, −40 to +125°C.
Limit
Symbol Parameter Conditions Typ Units
Min Max
Timing Characteristics
T
ON
Turn On Time
(11)
To 95% Level V
OUT
≤ 2.0V 100
µs
V
IN(MIN)
to 3.6V
V
OUT
> 2.0V 140
Transient Line Transient Response |δV
OUT
| T
rise
= T
fall
= 30µs
(11)
mV
6
Response δV
IN
= 600mV (pk - pk)
Load Transient Response |δV
OUT
| T
rise
= T
fall
= 1µs
(11)
I
OUT
= 0 mA to
140
300mA
I
OUT
= 1mA to
110
300mA
I
OUT
= 300mA to
80
1mA
I
OUT
= 0mA to
110
200mA
I
OUT
= 1mA to
80 mV
200mA
I
OUT
= 200mA to
60
1mA
I
OUT
= 0mA to
100
150mA
I
OUT
= 1mA to
70
150mA
I
OUT
= 150mA to
50
1mA
Overshoot on Start-up 0 2 %
I
IR
In-Rush Current
(11)
600 1000 mA
(11) This electrical specification is ensured by design.
Output Capacitor, Recommended Specifications
Limit
Parameter Conditions Typ Units
Min Max
C
OUT
Output Capacitor Capacitance
(1)
V
OUT
≥ 1.5V 4.7 2
µF
V
OUT
< 1.5V
(2)
2.2 1.6
ESR 5 500 mΩ
(1) The capacitor tolerance should be 30% or better over temperature. The full operating conditions for the application should be considered
when selecting a suitable capacitor to ensure that the minimum value of capacitance is always met. Recommended capacitor type is
X7R or X5R. (See capacitor section in Applications Hints)
(2) On lower voltage options, 2.2µF output capacitor may be used but some degradation in load transient (10 -15%) can be expected,
compared to a 4.7µF.
Copyright © 2006–2013, Texas Instruments Incorporated Submit Documentation Feedback 5
Product Folder Links: LP3991