LDO Design

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Low-dropout linear regulators
(LDOs) are commonly used to
provide power to low-voltage
digital circuits, where point-ofload
regulation is important. In
these applications, it is common
for the digital circuit to have
several different modes of operation.
As the digital circuit switches
from one mode of operation to
another, the load demand on the
LDO can change quickly. This
quick change of load results in a
temporary glitch of the LDO output
voltage. Most digital circuits
do not react favorably to large
voltage transients. For the digital
circuit designer, minimizing an
LDO’s transient response is an
important task.
LDOs are available in a wide
variety of output voltages and current capacities. Some
LDOs are tailored to applications where a good response to
a fast transient is important. The TPS751xx, TPS752xx,
TPS753xx, and TPS754xx families of LDOs from Texas
Instruments are examples of fast-transient-response LDOs.
The TPS751xx and TPS753xx families are rated at 1.5 A of
output current, while the TPS752xx and TPS754xx families
can provide up to 2 A. All four families use PMOS pass
elements to provide a low dropout voltage and low ground
current. These devices come in a PowerPADTM package
that provides an effective way of managing the power
dissipation in a TSSOP footprint.
Figure 1 shows the circuit elements of a typical LDO
application. The main components within a monolithic
LDO include a pass element, precision reference, feedback
network, and error amplifier. The input and output capacitors
are usually the only key elements of the LDO that are
not contained in a monolithic LDO. There are a number of
factors that affect the response of an LDO circuit to a load
transient. These factors include the internal compensation
of the LDO, the amount of output capacitance, and the
parasitics of the output capacitor.
【文件名】:07116@52RD_LDO.rar
【格　式】:rar
【大　小】:909K
【简　介】:
【目　录】:

comsrf

Low-dropout linear regulators
(LDOs) are commonly used to
provide power to low-voltage
digital circuits, where point-ofload
regulation is important. In
these applications, it is common
for the digital circuit to have
several different modes of operation.
As the digital circuit switches
from one mode of operation to
another, the load demand on the
LDO can change quickly. This
quick change of load results in a
temporary glitch of the LDO output
voltage. Most digital circuits
do not react favorably to large
voltage transients. For the digital
circuit designer, minimizing an
LDO’s transient response is an
important task.
LDOs are available in a wide
variety of output voltages and current capacities. Some
LDOs are tailored to applications where a good response to
a fast transient is important. The TPS751xx, TPS752xx,
TPS753xx, and TPS754xx families of LDOs from Texas
Instruments are examples of fast-transient-response LDOs.
The TPS751xx and TPS753xx families are rated at 1.5 A of
output current, while the TPS752xx and TPS754xx families
can provide up to 2 A. All four families use PMOS pass
elements to provide a low dropout voltage and low ground
current. These devices come in a PowerPADTM package
that provides an effective way of managing the power
dissipation in a TSSOP footprint.
Figure 1 shows the circuit elements of a typical LDO
application. The main components within a monolithic
LDO include a pass element, precision reference, feedback
network, and error amplifier. The input and output capacitors
are usually the only key elements of the LDO that are
not contained in a monolithic LDO. There are a number of
factors that affect the response of an LDO circuit to a load
transient. These factors include the internal compensation
of the LDO, the amount of output capacitance, and the
parasitics of the output capacitor.
【文件名】:07116@52RD_LDO.rar
【格　式】:rar
【大　小】:909K
【简　介】:
【目　录】: