Datasheet

LP3891
SNVS235D –SEPTEMBER 2003–REVISED APRIL 2013 www.ti.com
ELECTRICAL CHARACTERISTICS
Limits in standard typeface are for T
J
= 25°C, and limits in boldface type apply over the full operating temperature range.
Unless otherwise specified: V
IN
= V
O
(NOM) + 1V, V
BIAS
= 4.5V, I
L
= 10 mA, C
IN
= C
OUT
= 10 µF, V
S/D
= V
BIAS
.
Typical
Symbol Parameter Conditions MIN
(1)
MAX
(1)
Units
(2)
V
O
Output Voltage Tolerance 10 mA ≤ I
L
≤ 0.8A, V
O
(NOM) + 1V ≤ V
IN
≤ 1.198 1.234
1.216
5.5V, 1.186 1.246
4.5V ≤ V
BIAS
≤ 6V
1.478 1.522
1.5 V
1.455 1.545
1.773 1.827
1.8
1.746 1.854
ΔV
O
/ΔV
IN
Output Voltage Line Regulation
(3)
V
O
(NOM) + 1V ≤ V
IN
≤ 5.5V 0.01 %/V
ΔV
O
/ΔI
L
Output Voltage Load Regulation
(4)
10 mA ≤ I
L
≤ 0.8A 0.04
%/A
(5)
0.06
V
DO
Dropout Voltage
(6)
I
L
= 0.8A (TO220 and TO263 only) 300
100
400
mV
I
L
= 0.8A (SO PowerPAD only) 320
115
430
I
Q
(V
IN
) Quiescent Current Drawn from V
IN
10 mA ≤ I
L
≤ 0.8A 7
3 mA
Supply 8
V
S/D
≤ 0.3V 1
0.03 µA
30
I
Q
(V
BIAS
) Quiescent Current Drawn from 10 mA ≤ I
L
≤ 0.8A 2
1 mA
V
BIAS
Supply 3
V
S/D
≤ 0.3V 1
0.03 µA
30
I
SC
Short-Circuit Current V
OUT
= 0V 2.5 A
Shutdown Input
V
SDT
Output Turn-off Threshold Output = ON 1.3 0.7
V
Output = OFF 0.7 0.3
Td (OFF) Turn-OFF Delay R
LOAD
X C
OUT
<< Td (OFF) 20
µs
Td (ON) Turn-ON Delay R
LOAD
X C
OUT
<< Td (ON) 15
I
S/D
S/D Input Current V
S/D
=1.3V 1
µA
V
S/D
≤ 0.3V −1
AC Parameters
PSRR (V
IN
) Ripple Rejection for V
IN
Input V
IN
= V
OUT
+1V, f = 120 Hz 80
Voltage
V
IN
= V
OUT
+ 1V, f = 1 kHz 65
dB
PSRR Ripple Rejection for V
BIAS
Voltage V
BIAS
= V
OUT
+ 3V, f = 120 Hz 70
(V
BIAS
)
V
BIAS
= V
OUT
+ 3V, f = 1 kHz 65
Output Noise Density f = 120 Hz µV/root−
1
Hz
e
n
Output Noise Voltage BW = 10 Hz − 100 kHz, V
OUT
= 1.8V 150
µV (rms)
BW = 300 Hz − 300 kHz, V
OUT
= 1.8V 90
(1) Limits are specified through testing, statistical correlation, or design.
(2) Typical numbers represent the most likely parametric norm for 25°C operation.
(3) Output voltage line regulation is defined as the change in output voltage from nominal value resulting from a change in input voltage.
(4) If used in a dual-supply system where the regulator load is returned to a negative supply, the output pin must be diode clamped to
ground.
(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.
(6) Dropout voltage is defined as the minimum input to output differential required to maintain the output with 2% of nominal value. The SO
PowerPAD-8 package devices have a slightly higher dropout voltage due to increased band wire resistance.
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