LX8385A-00CDD Microsemi Analog Mixed Signal Group, LX8385A-00CDD Datasheet - Page 5
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LX8385A-00CDD
Manufacturer Part Number
LX8385A-00CDD
Description
IC REG LDO POS 3A ADJ OUT TO263
Manufacturer
Microsemi Analog Mixed Signal Group
Datasheet
1.LX8385-00CP.pdf
(11 pages)
Specifications of LX8385A-00CDD
Regulator Topology
Positive Adjustable
Voltage - Output
Adjustable
Voltage - Input
Up to 10V
Voltage - Dropout (typical)
1.1V @ 3A
Number Of Regulators
1
Current - Output
3A (Min)
Operating Temperature
0°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
TO-263-3, D²Pak (3 leads + Tab), TO-263AA
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Limit (min)
-
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LX8385A-00CDD
Manufacturer:
MSC
Quantity:
20 000
Copyright © 2000
Rev. 2.0b, 2005-10-25
Dropout (LDO) voltage regulators. They have all of the standard
self-protection features expected of a voltage regulator: short
circuit protection, safe operating area protection and automatic
thermal shutdown if the device temperature rises above
approximately 165°C.
LX8385/85A/85B series. Please see the table below for
recommended minimum capacitor values.
voltage tolerance and superior reference stability when measured
against the older pin-compatible regulator types that they replace.
STABILITY
compensation system. Many types of capacitors are available,
with
temperature coefficients, and equivalent series impedances. For
all operating conditions, connection of a 220µF aluminum
electrolytic capacitor or a 47µF (<400mΩ ESR) solid tantalum
capacitor between the output terminal and ground will guarantee
stable operation.
adjust (ADJ) pin and ground, ripple rejection will be improved
(please see the section entitled “RIPPLE REJECTION”). When
ADJ pin bypassing is used, the required output capacitor value
increases. Output capacitor values of 220µF (aluminum) or 47µF
(tantalum) provide for all cases of bypassing the ADJ pin. If an
ADJ pin bypass capacitor is not used, smaller output capacitor
values are adequate. The table below shows recommended
minimum capacitance values for operation.
system under rapidly changing current load conditions, designers
generally use several output capacitors connected in parallel.
Such an arrangement serves to minimize the effects of the
parasitic resistance (ESR) and inductance (ESL) that are present
in all capacitors. Cost-effective solutions that sufficiently limit
ESR and ESL effects generally result in total capacitance values
in the range of hundreds to thousands of microfarads, which is
more than adequate to meet regulator output capacitor
specifications. Output capacitance values may be increased
without limit.
transient response characteristics of the regulator in a power
system under changing loads. The effects of different capacitor
types and values on transient response parameters, such as
overshoot and under-shoot, can be compared quickly in order to
develop an optimum solution.
Use of an output capacitor is REQUIRED with the
INPUT
The LX8385/85A/85B Series ICs are easy to use Low-
These regulators offer a more tightly controlled reference
The output capacitor is part of the regulator’s frequency
If a bypass capacitor is connected between the output voltage
To ensure good transient response from the power supply
The circuit shown in Figure 1 can be used to observe the
10µF
10µF
TM
different
Minimum Capacitor Values
15µF Tantalum, 100µF Aluminum
47µF Tantalum, 220µF Aluminum
capacitance
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
OUTPUT
value
tolerances,
A P P L I C A T I O N N O T E S
Integrated Products Division
Microsemi Inc.
capacitance
None
®
ADJ
15µF
OVERLOAD RECOVERY
regulators are equipped with Safe Operating Area (SOA)
protection. The SOA circuit limits the regulator's maximum
output current to progressively lower values as the input-to-output
voltage difference increases. By limiting the maximum output
current, the SOA circuit keeps the amount of power that is
dissipated in the regulator itself within safe limits for all values of
input-to-output voltage within the operating range of the
regulator. The LX8385/85A/85B SOA protection system is
designed to be able to supply some output current for all values of
input-to-output voltage, up to the device breakdown voltage.
prevent a power supply system from returning to regulated opera-
tion after removal of an intermittent short circuit at the output of
the regulator. This is a normal mode of operation, which can be
seen, in most similar products, including older devices such as
7800 series regulators. It is most likely to occur when the power
system input voltage is relatively high and the load impedance is
relatively low.
output voltages are very close to zero. The output voltage closely
follows the rising input voltage, and the input-to-output voltage
difference is small. The SOA circuit therefore permits the
regulator to supply large amounts of current as needed to develop
the designed voltage level at the regulator output.
regulated voltage to a resistive load under steady state conditions.
A moderate input-to-output voltage appears across the regulator
but the voltage difference is small enough that the SOA circuitry
allows sufficient current to flow through the regulator to develop
the designed output voltage across the load resistance. If the
output resistor is short-circuited to ground, the input-to-output
voltage difference across the regulator suddenly becomes larger
by the amount of voltage that had appeared across the load
resistor. The SOA circuit reads the increased input-to-output
voltage, and cuts back the amount of current that it will permit the
regulator to supply to its output terminal. When the short circuit
across the output resistor is removed, all the regulator output
current will again flow through the output resistor. The maximum
current that the regulator can supply to the resistor will be limited
by the SOA circuit, based on the large input-to-output
3A Low Dropout Positive Regulators
Like almost all IC power regulators, the LX8385/85A/85B
Under some conditions, a correctly operating SOA circuit may
When the power system is started “cold”, both the input and
Now consider the case where the regulator is supplying
Supply
Power
FIGURE 1 - DYNAMIC INPUT AND OUTPUT TEST
P
RODUCTION
IN
LX8385x
ADJ
Star Ground
D
ATA
S
OUT
HEET
(Larger resistor)
Minim um Load
LX8385x-xx
10m s
R
Full Load
DSON
(Sm aller
resistor)
<< R
1 sec
L
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