Datasheet

LP38851
SNVS492C –JUNE 2007–REVISED APRIL 2013 www.ti.com
ELECTRICAL CHARACTERISTICS
Unless otherwise specified: V
OUT
= 0.80V, V
IN
= V
OUT(NOM)
+ 1V, V
BIAS
= 3.0V, V
EN
= V
BIAS
, I
OUT
= 10 mA, C
IN
= C
OUT
= 10 µF,
C
BIAS
= 1 µF, C
SS
= open. Limits in standard type are for T
J
= 25°C only; limits in boldface type apply over the junction
temperature (T
J
) range of -40°C to +125°C. Minimum and Maximum limits are specified through test, design, or statistical
correlation. Typical values represent the most likely parametric norm at T
J
= 25°C, and are provided for reference purposes
only.
Symbol Parameter Conditions Min Typ Max Units
V
OUT(NOM)
+1V ≤ V
IN
≤ V
BIAS
≤ 4.5V
(1)
492.5 507.5
3.0V ≤ V
BIAS
≤ 5.5V, 500.
485.0 515.0
10 mA ≤ I
OUT
≤ 800 mA
V
ADJ
V
ADJ
Accuracy mV
V
OUT(NOM)
+1V ≤ V
IN
≤ V
BIAS
≤ 4.5V
(1)
3.0V ≤ V
BIAS
≤ 5.5V,
490.0 500. 510.0
10 mA ≤ I
OUT
≤ 800 mA,
0°C ≤ T
J
≤ +125°C
3.0V ≤ V
BIAS
≤ 5.5V 0.80 1.20
V
OUT
V
OUT
Range V
4.5V ≤ V
BIAS
≤ 5.5V 0.80 1.80
ΔV
OUT
/ΔV
IN
Line Regulation, V
IN
(2)
V
OUT(NOM)
+1V ≤ V
IN
≤ V
BIAS
- 0.04 - %/V
ΔV
OUT
/ΔV
BIAS
Line Regulation, V
BIAS
(2)
3.0V ≤ V
BIAS
≤ 5.5V - 0.10 - %/V
ΔV
OUT
/ΔI
OUT
Output Voltage Load Regulation
(3)
10 mA ≤ I
OUT
≤ 800 mA - 0.2 - %/A
150
V
DO
Dropout Voltage
(4)
I
OUT
= 800 mA - 115 mV
200
V
OUT
= 0.80V
8.5
V
BIAS
= 3.0V - 7.0 mA
9.0
Quiescent Current Drawn from V
IN
10 mA ≤ I
OUT
≤ 800 mA
I
GND(IN)
Supply
100
V
EN
≤ 0.5V 1 μA
300
3.8
10 mA ≤ I
OUT
≤ 800 mA - 3.0 mA
4.5
Quiescent Current Drawn from
I
GND(BIAS)
V
BIAS
Supply
170
V
EN
≤ 0.5V 100 μA
200
2.20 2.70
UVLO Under-Voltage Lock-Out Threshold V
BIAS
rising until device is functional 2.45 V
2.00 2.90
V
BIAS
falling from UVLO threshold until 60 300
UVLO
(HYS)
Under-Voltage Lock-Out Hysteresis 150 mV
device is non-functional 50 350
V
IN
= V
OUT(NOM)
+ 1V,
I
SC
Output Short-Circuit Current - 2.3 - A
V
BIAS
= 3.0V, V
OUT
= 0.0V
Soft-Start
r
SS
Soft-Start internal resistance 11.0 14.0 17.0 kΩ
Soft-Start time
t
SS
C
SS
= 10 nF - 700 - μs
t
SS
= C
SS
× r
SS
× 5
Enable
V
EN
= V
BIAS
- 0.01 -
I
EN
ENABLE pin Current μA
-24 -43
V
EN
= 0.0V, V
BIAS
= 5.5V -35
-21 -50
1.00 1.50
V
EN(ON)
Enable Voltage Threshold V
EN
rising until Output = ON 1.25 V
0.90 1.55
V
EN
falling from V
EN(ON)
until Output = 50 150
V
EN(HYS)
Enable Voltage Hysteresis 100 mV
OFF 30 200
t
OFF
Turn-OFF Delay Time R
LOAD
x C
OUT
<< t
OFF
- 20 -
µs
t
ON
Turn-ON Delay Time R
LOAD
x C
OUT
<< t
ON
- 15 -
AC Parameters
(1) V
IN
cannot exceed either V
BIAS
or 4.5V, whichever value is lower.
(2) Output voltage line regulation is defined as the change in output voltage from nominal value resulting from a change in input voltage.
(3) Output voltage load regulation is defined as the change in output voltage from nominal value as the load current increases from no load
to full load.
(4) Dropout voltage is defined as the input to output voltage differential (V
IN
- V
OUT
) where the input voltage is low enough to cause the
output voltage to drop 2% from the nominal value.
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