Datasheet

LP3991
SNVS296H –DECEMBER 2006–REVISED MAY 2013 www.ti.com
Electrical Characteristics
(1)
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
Input Voltage See
(2)
1.65 3.6
V
IN
V
See
(3)(4)(5)
4.0
ΔV
OUT
Output Voltage Tolerance V
IN
= V
IN(NOM)
to 3.6V -1.0 1.0
I
LOAD
= 1 to 300mA -3.0 3.0
%
Temperature -2.5 2.5
(T
J
)=
-25°C to +85°C
Line Regulation Error V
IN
= V
OUT(NOM)
+0.5V to 3.6V,
I
OUT
= 1mA 0.05 1 %/V
0.8V ≤ V
OUT
≤ 2.8V
Load Regulation Error I
OUT
= 1mA to 300mA 10 60 µV/mA
V
DO
Dropout Voltage
(6)
1.8 ≤ V
OUT
≤ 2.5V I
OUT
= 150mA 55 90
I
OUT
= 300mA 110 180
mV
V
OUT
> 2.5V I
OUT
= 150mA 40 80
I
OUT
= 300mA 75 160
I
LOAD
Minimum Load Current See
(7)
0 mA
I
Q
Quiescent Current V
EN
= 950mV, I
OUT
= 0mA 50 100
V
EN
= 950mV, I
OUT
= 300mA 120 225 µA
V
EN
= 0.4V 0.001 1.0
I
SC
Short Circuit Current Limit V
IN
= 3.6V
(8)
550 900 mA
I
OUT
Maximum Output Current 300 mA
PSRR Power Supply Rejection Ratio
(9)
f = 1kHz, I
OUT
= 1mA to 300mA 65 dB
BW = 10Hz to 100kHz,
e
n
Output noise Voltage
(9)
280 µV
RMS
V
IN
= 4.2V, C
OUT
= 4.7µF
T
SHUTDOWN
Thermal Shutdown Temperature 160
°C
Hysteresis 20
Enable Control Characteristics
I
EN
(10)
Maximum Input Current at V
EN
V
EN
= 0V, V
IN
= 3.6V 0.001
µA
Input
V
EN
= V
IN
= 3.6V 3 5.5
V
IL
Low Input Threshold V
IN
= 1.65V to 3.6V 0.4 V
V
IH
High Input Threshold V
IN
= 1.65V to 3.6V 0.95 V
(1) All limits are ensured. All electrical characteristics having room-temperature limits are tested during production at T
J
= 25°C or correlated
using Statistical Quality Control methods. Operation over the temperature specification is ensured by correlating the electrical
characteristics to process and temperature variations and applying statistical process control.
(2) V
IN(MIN)
= V
OUT(NOM)
+ 0.5V or 1.65V, whichever is greater. (See post DC/DC convertor example in application information section).
(3) The device will operate with input voltages up to 4.0V. However special care should be taken in relation to thermal dissipation and the
need to derate the maximum allowable ambient temperature.
(4) The maximum ambient temperature (T
A(max)
) is dependant on the maximum operating junction temperature (T
J(max-op)
= 125°C), the
maximum power dissipation of the device in the application (P
D(max)
), and the junction to ambient thermal resistance of the part /
package in the application (θ
JA
), as given by the following equation: T
A(max)
= T
J(max-op)
- (θ
JA
× P
D(max)
).
(5) Junction to ambient thermal resistance is dependant on the application and board layout. In applications where high maximum power
dissipation is possible, special care must be paid to thermal dissipation issues in board design.
(6) Dropout voltage is voltage difference between input and output at which the output voltage drops to 100mV below its nominal value.
This parameter is only specified for output voltages above 1.8V.
(7) The device maintains the regulated output voltage without a load.
(8) Short circuit current is measured with V
OUT
pulled to 0V.
(9) This electrical specification is ensured by design.
(10) Enable Pin has an internal 1.2MΩ typical, resistor connected to GND.
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