Soft-Start capacitor connection. Used to control the rise time of
V
OUT
at turn-on.
Device Enable, High = On, Low = Off.
The unregulated voltage input
Ground
The feedback connection to set the output voltage
The regulated output voltage
The supply for the internal control and reference circuitry.
No internal connection
The TO220 and TO263 TAB is a thermal and electrical connection
that is physically attached to the backside of the die, and used as
a thermal heat-sink connection. See the Application Information
section for details.
The PSOP DAP is a thermal connection only that is physically
attached to the backside of the die, and used as a thermal heat-
sink connection. See the Application Information section for details.
TAB
TAB
-
TAB
-
-
DAP
DAP
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2
LP38851
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature Range
Lead Temperature
Soldering, 5 seconds
ESD Rating
Human Body Model (Note 2)
Power Dissipation (Note 3)
V
IN
Supply Voltage (Survival)
V
BIAS
Supply Voltage (Survival)
V
SS
SoftStart Voltage (Survival)
−65°C to +150°C
260°C
±2 kV
Internally Limited
−0.3V to +6.0V
−0.3V to +6.0V
−0.3V to +6.0V
V
OUT
Voltage (Survival)
I
OUT
Current (Survival)
Junction Temperature
−0.3V to +6.0V
Internally Limited
−40°C to +150°C
(Note 1)
(V
OUT
+ V
DO
) to V
BIAS
3.0V to 5.5V
4.5V to 5.5V
0.0V to V
BIAS
0 mA to 800 mA
−40°C to +125°C
Operating Ratings
V
IN
Supply Voltage
V
BIAS
Supply Voltage
0.8V
≤
V
OUT
≤
1.2V
1.2V < V
OUT
≤
1.8V
V
EN
Voltage
I
OUT
Junction Temperature Range
(Note 3)
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 guaranteed 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
V
OUT(NOM)
+1V
≤
V
IN
≤
V
BIAS
≤
4.5V,
See (Note 7)
3.0V
≤
V
BIAS
≤
5.5V,
V
ADJ
V
ADJ
Accuracy
10 mA
≤
I
OUT
≤
800 mA
mV
490.0
500.
510.0
MIN
492.5
485.0
TYP
MAX
507.5
515.0
Units
Electrical Characteristics
500.
V
OUT(NOM)
+1V
≤
V
IN
≤
V
BIAS
≤
4.5V,
See (Note 7)
3.0V
≤
V
BIAS
≤
5.5V,
0°C
≤
T
J
≤
+125°C
10 mA
≤
I
OUT
≤
800 mA,
0.80
0.80
-
-
-
-
0.04
0.10
0.2
115
1.20
1.80
-
-
-
150
200
8.5
9.0
100
300
3.8
4.5
170
200
2.70
2.90
300
350
-
V
OUT
ΔV
OUT
/ΔV
IN
V
OUT
Range
Line Regulation, V
IN
(Note 4)
Output Voltage Load Regulation
(Note 5)
Dropout Voltage (Note 6)
3.0V
≤
V
BIAS
≤
5.5V
4.5V
≤
V
BIAS
≤
5.5V
V
OUT(NOM)
+1V
≤
V
IN
≤
V
BIAS
3.0V
≤
V
BIAS
≤
5.5V
10 mA
≤
I
OUT
≤
800 mA
I
OUT
= 800 mA
V
OUT
= 0.80V
V
BIAS
= 3.0V
V
EN
≤
0.5V
V
%/V
%/V
%/A
mV
ΔV
OUT
/ΔV
BIAS
Line Regulation, V
BIAS
(Note 4)
ΔV
OUT
/ΔI
OUT
V
DO
I
GND(IN)
Quiescent Current Drawn from
V
IN
Supply
-
7.0
mA
10 mA
≤
I
OUT
≤
800 mA
1
-
3.0
100
2.20
2.00
60
50
-
2.45
150
2.5
μA
mA
μA
V
mV
A
I
GND(BIAS)
Quiescent Current Drawn from
V
BIAS
Supply
Under-Voltage Lock-Out
Threshold
Under-Voltage Lock-Out
Hysteresis
Output Short-Circuit Current
10 mA
≤
I
OUT
≤
800 mA
V
EN
≤
0.5V
V
BIAS
rising until device is functional
V
BIAS
falling from UVLO threshold until
device is non-functional
V
IN
= V
OUT(NOM)
+ 1V,
V
BIAS
= 3.0V, V
OUT
= 0.0V
UVLO
UVLO
(HYS)
I
SC
3
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LP38851
Symbol
Soft-Start
r
SS
t
SS
Enable
Parameter
Soft-Start internal resistance
Soft-Start time
t
SS
= C
SS
× r
SS
× 5
C
SS
= 10 nF
Conditions
MIN
11.0
-
TYP
14.0
700
MAX
17.0
-
Units
kΩ
μs
V
EN
= V
BIAS
I
EN
ENABLE pin Current
V
EN
= 0.0V, V
BIAS
= 5.5V
V
EN
rising until Output = ON
V
EN
falling from V
EN(ON)
until Output =
OFF
R
LOAD
x C
OUT
<< t
OFF
R
LOAD
x C
OUT
<< t
ON
V
IN
= V
OUT(NOM)
+ 1V,
f = 120 Hz
V
IN
= V
OUT(NOM)
+ 1V,
f = 1 kHz
V
BIAS
= V
OUT(NOM)
+ 3V,
f = 120 Hz
V
BIAS
= V
OUT(NOM)
+ 3V,
f = 1 kHz
f = 120 Hz
BW = 10 Hz − 100 kHz
BW = 300 Hz − 300 kHz
-
-24
-21
1.00
0.90
50
30
-
-
0.01
-35
1.25
100
20
15
-
-43
-50
1.50
1.55
150
200
-
-
μA
V
EN(ON)
V
EN(HYS)
t
OFF
t
ON
Enable Voltage Threshold
Enable Voltage Hysteresis
Turn-OFF Delay Time
Turn-ON Delay Time
V
mV
µs
AC Parameters
PSRR
(V
IN
)
Ripple Rejection for V
IN
Input
Voltage
-
-
-
-
-
-
-
72
61
54
53
1
150
90
-
-
dB
-
-
-
-
-
µV/
√
Hz
µV
RMS
PSRR
(V
BIAS
)
Ripple Rejection for V
BIAS
Voltage
Output Noise Density
e
n
Output Noise Voltage
Thermal Parameters
T
SD
T
SD(HYS)
θ
J-A
Thermal Shutdown Junction
Temperature
Thermal Shutdown Hysteresis
Thermal Resistance, Junction to
Ambient(Note 3)
Thermal Resistance, Junction to
Case(Note 3)
TO220-7
TO263-7
PSOP-8
TO220-7
TO263-7
PSOP-8
-
-
-
-
-
-
-
-
160
10
60
60
168
3
3
11
-
-
-
-
-
-
-
-
°C/W
°C
θ
J-C
Note 1:
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the
device is intended to be functional, but does not guarantee specific performance limits. For guaranteed specifications and conditions, see the Electrical
Characteristics.
Note 2:
The human body model is a 100 pF capacitor discharged through a 1.5k resistor into each pin. Test method is per JESD22-A114.
Note 3:
Device power dissipation must be de-rated based on device power dissipation (P
D
), ambient temperature (T
A
), and package junction to ambient thermal
resistance (θ
JA
). Additional heat-sinking may be required to ensure that the device junction temperature (T
J
) does not exceed the maximum operating rating. See
the Application Information section for details.
Note 4:
Output voltage line regulation is defined as the change in output voltage from nominal value resulting from a change in input voltage.
Note 5:
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.
Note 6:
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
