LT3071EUFD LINER [Linear Technology], LT3071EUFD Datasheet - Page 23

• Manufacturer Part Number: LT3071EUFD
• Description: 5A, Low Noise, Programmable Output, 85mV Dropout Linear Regulator with Analog Margining
• Manufacturer: LINER [Linear Technology]

ApplicAtions inFormAtion
Quieting the Noise
The LT3071 offers numerous noise performance advan-
tages. Each LDO has several sources of noise. An LDO’s
most critical noise source is the reference, followed by
the LDO error amplifier. Traditional low noise regulators
buffer the voltage reference out to an external pin (usually
through a large value resistor) to allow for bypassing and
noise reduction of reference noise. The LT3071 deviates
from the traditional voltage reference by generating a
low voltage V
nal resistor ≅19k. This intermediate impedance node
(REF/BYP) facilitates external filtering directly. A 10nF filter
REF
from a reference current into an inter-
1.5V
V
IN
2.2V TO 3.6V
V
BIAS
330µF
1nF
NC
Figure 6. 1.5V to 1.2V Linear Regulator
IN
EN
V
V
V
MARGA
VIOC
O0
O1
O2
2.2µF
LT3071
BIAS
GND
REF/BYP
PWRGD
SENSE
I
OUT
MON
50k
capacitor minimizes reference noise to 10µV
600mV REF/BYP pin, equivalently a 17µV contribution to
output noise at V
Characteristics for Noise vs Output Voltage performance
as a function of C
This approach also accommodates reference sharing
between LT3071 regulators that are hooked up in cur-
rent sharing applications. The REF/BYP filter capacitor
delays the initial power-up time by a factor of the RC time
constant. V
time is significantly reduced and well controlled coming
out of nap mode (EN:LO↑HI).
*X5R OR X7R CAPACITORS
0.01µF
2.2µF*
PWRGD
3071 F06
1k
4.7µF*
REF
remains active in nap mode, thus start-up
OUT
REF/BYP
10µF*
= 1V. See the Typical Performance
V
2V AT 5A
FULL SCALE
V
1.2V
5A
MON
OUT
.
LT3071
RMS

at the
3071f