LX8385B-33CDD-TR [MICROSEMI]
Fixed Positive LDO Regulator, 3.3V, BIPolar,;
| 型号： | LX8385B-33CDD-TR |
| 厂家： | 
Microsemi |
| 描述： | Fixed Positive LDO Regulator, 3.3V, BIPolar, 输出元件 调节器 |
| 文件： | 总11页 (文件大小：719K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
KEY FEATURES
DESCRIPTION
Three-Terminal Adjustable Or
Fixed Output
Guaranteed 1% Voltage
Reference Accuracy Over Line,
Load, And Temperature
(LX8385B)
Guaranteed < 5V Headroom At
3A (LX83
GuarantHeadroom At
3A (LX885B
The LX8385/85A/85B Series ICs are
The LX8385/85A/85B Series devices are
positive regulators designed to provide 3A pin-compatible with earlier 3-terminal
output current. These regulators yield regulators, such as the 117 series products,
higher efficiency than currently available but they do require input and output
devices with all internal circuitry designed capacitors. A minimum 10µF capacitor is
to operate down to a 1V input-to-output required on the input and a 15µF or greater
differential. In each of these products, the on the output of these new devices for
dropout voltage is fully specified as a stability. Although, these capacitors are
function of load current. Dropout is generally included in most regulator designs.
guaranteed at
a
maximum of 1.3V
The LX8385/85A/85B Series quiescent
.% Legulat
% Load on
(8385A/B) and 1.5V (8385) at maximum current flows into the load, thereby
output current, decreasing at lower load increasing efficiency. This feature contrasts
currents.
with PNP regulators where up to 10% of the
In addition, on-chip trimming adjusts the output current is wasted as quiescent
reference voltage tolerance to 1% maximum current.
ACATIONS
at room temperature and 2% maximum over
The LX8385-xxI is specified over th
High Efficiency Linear
Rulators
PRegulators For Switching
wer Supplies
the 0 to 125°C range for the LX8385A. The industrial temperature range -25°C
LX8385B offers 0.8% tolerance at room 125°C, while the LX8385-xxC A-xxC
temperature and 1.0% maximum over line, 85B-xxC is specified over the cercial
load and temperature. Fixed versions are range of 0°C to 125°C.
also available and specified in the Available
Battery Chargers
Constant Current Regulators
Graphics & Standard Supplies
Processor I/O Supply
Low Voltage Memory & Chipset
Supplies
Options table below.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://ww
PRODUCT HIGHLIGHT
IN
OU
.3V
t 3A
OUTPUT
PART #
5V
LX8385A
VOLTAGE
+
121Ω
*1500µF
6MV1500GX
Sanyo
LX8385/85A/85B-00
LX8385/85A/85B-33
LX8385/85A/85B-05
Adjustable
3.3V
1%
ADJ
+
1500µF
2x 6MV1500GX
Sanyo
200Ω
5.0V
1%
Table 1 - Available Options
PACKAGE ORDER INFO
Plastic TO-220
Plastic TO-263
3-Pin
Plastic TO-252
Max Ref Max Dropout DT
P
DD
3-Pin
(D-Pak) 3-Pin
TA (°C)
Accuracy
Voltage
RoHS Compliant
RoHS Compliant
RoHS Compliant
Transition DC: 0532
Transition DC: 0543
LX8385-xxCP
LX8385A-xxCP
LX8385B-xxCP
LX8385-xxIP
Transition DC: 0535
2.0%
2.0%
1.0%
1.5V
1.3V
1.3V
1.5V
LX8385-xxCDT
LX8385A-xxCDT
LX8385B-xxCDT
LX8385-xxIDT
LX8385-xxCDD
LX8385A-xxCDD
LX8385B-xxCDD
LX8385-xxIDD
0 to 125
-25 to 125 2.0%
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8385-xxCP-TR)
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Integrated Products Division
Page 1
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
ABSOLUTE MAXIMUM RATINGS (NOTE 1)
PACKAGE PIN OUT
Power Dissipation................................................................................... Internally Limited
Input Voltage ................................................................................................................ 10V
Input to Output Voltage Differential............................................................................. 10V
Operating Junction Temperature................................................................................150°C
Storage Temperature Range....................................................................... -65°C to 150 °C
Peak Package Solder Reflow Temp (40 seconds max. exposure).................260°C (+0, -5)
TAB is VOUT
3
VIN
2
VOUT
ADJ /
GND*
1
Note 1: Exceeding these ratings could cause damage to the device. All voltages are with respect to
Ground. Currents are positive into, negative out of specified terminal.
-PIN)
w)
VOUT
VIN
THERMAL DATA
2
1
VOUT
ADJ/
GND*
Plastic TO-263 3-Pin
DD
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
THERMAL RESISTANCE-JUNCTION TO TAB, θJT
0°C/W
C/W
DT PACKAGE (3-PIN)
(Top View)
TAB is VOUT
Plastic TO-220 3-Pin
P
3
VIN
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
THERMAL RESISTANCE-JUNCTION TO TAB, θJT
0°C/W
C/W
2
VOUT
ADJ /
GND*
1
Plastic TO-252 3-Pin
DT
P PACKAGE (3-PIN)
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ
THERMAL RESISTANCE-JUNCTION TO TAB, θJ
C/W
2.7°C/W
(Top View)
*Pin 1 is GND for fixed voltage versions
RoHS 100% Matte Tin Lead Finish
Junction Temperature Calculation: TJ = TA + (PD x
The θJA & θJT numbers are guidelines for the thermal performance the device/pc-board
system. All of the above assume no ambiw.
LOCK DIAGRAM
VIN
Thermal
Limit Circuit
Bandgap
Circuit
Control
Circuit
Output
Circuit
VOUT
SOA
Protection
Circuit
ADJ or
GND*
Current
Limit Circuit
*Pin 1 is GND for fixed voltage versions
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Page 2
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature for the LX8385x-xxC with
0°C ≤ TA ≤ 125°C and the LX8385-xxI with -25°C ≤ TA ≤ 125°C except where otherwise noted. Test conditions: VIN -VOUT = 3V;
IOUT = 3A. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient
temperature.
LX8385x-xx
Parameter
Symbol
Test Conditions
Units
Min
Max
LX8385-00 / 8385A-00 / 8385B-00 (ADJUSTABLE)
`
IOUT = 10mA, TA = 25°C
10mA < IOUT < 3A, 1.5V < (VIN -VOUT),
IN < 10V, P < PMAX
1.23
1.225
40
1.
0
50
1.250
250
62
270
1.260
1.262
V
V
V
V
Reference Voltage
(Note 4)
LX8385/85A-00
V
VREF
IOUT = 10mA, TA = 25°C
LX8385B-00
10mA < IOUT < 3A, 1.5V < (VIN -VOUT),
V
IN < 10V, P < PMAX
Δ VREF
(VIN)
Δ VREF
Line Regulation (Note 2)
Load Regulation (Note 2)
Thermal Regulation
1.5V < (VIN -VOUT), VIN < 7V, IOUT = 10
0.015
0.15
0.01
83
0.2
0.5
%
%
VOUT > VREF, VIN - VOUT =
10mA < IOUT < 3A
(IOUT
)
ΔVOUT
(Pwr)
TA = 25°C, 20ms pulse
0.04
% / W
dB
V
V
OUT = 5V, f= 120Hz, C= 100µF alum,
IN = 6.5V, CADJ = 3A
Ripple Rejection (Note 3)
65
Adjust Pin Current
IADJ
55
0.2
1.2
1.1
2
100
5
µA
µA
V
Adjust Pin Current Change (Note 4)
ΔIADJ
10mA < IOUT < IN -VOUT), VIN<10V
ΔVREF = 1%, IOUT
Dropout Voltage
LX8385-00
1.5
1.3
10
ΔV
LX8385A/85B-00
ΔV1%, IOUT = 3
V
Minimum Load Current
IOUT(MIN)
IOUT(MAX)
< 10V
mA
A
Maximum Output Current
Long Term Stability (Note 3)
Temperature Stability (Note 3)
T) < 7IN < 10V
3
3.5
0.3
0.25
ΔVt) TA = 125°C, 10 hours
1
%
%
RMS Output Noise (% of VOUT
(Note 3)
)
25°C, 10Hz < f < 10kHz
0.003
%
LX8385-33/ 8385A-33 (3.3V
`
VIN = 5V, IOUT = 0mA, TA = 25°C
4.75V < VIN < 10V, 0mA < IOUT < 3A, P < PMAX
VIN = 5V, IOUT = 0mA, TA = 25°C
4.75V < VIN < 10V, 0A < IOUT < 3A, P < PMAX
4.75V < VIN < 7V
3.267
3.235
3.274
3.267
3.3
3.3
3.3
3.3
1
3.333
3.365
3.326
3.333
6
V
V
Output Voltage
(Note 4)
VOUT
V
V
mV
mV
ΔVOUT
(VIN)
Line Regulation (note 2
4.75V < VIN < 10V
2
10
ΔVOUT
Load Regulation (note 2)
Thermal Regulation
VIN = 5V, 0mA < IOUT < IOUT(MAX)
TA = 25°C, 20ms pulse
5
15
mV
(IOUT
)
ΔVOUT
(Pwr)
0.01
0.02
% / W
Ripple Rejection (note 3)
Quiescent Current
COUT = 100µF (Tantalum), IOUT = 3A
0mA < IOUT < IOUT(MAX), 4.75V < V < 10V
ΔVOUT = 1%, IOUT < IOUT(MAX)
60
83
4
dB
mA
V
IQ
10
1.5
1.3
1.2
1.1
Dropout Voltage
LX8385-33
LX8385A/85B-33
ΔV
ΔVOUT = 1%, IOUT < IOUT(MAX)
V
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Page 3
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS (CONTINUED)
Unless otherwise specified, the following specifications apply over the operating ambient temperature for the LX8385x-xxC with
0°C ≤ TA ≤ 125°C and the LX8385-xxI with -25°C ≤ TA ≤ 125°C except where otherwise noted. Test conditions: VIN -VOUT = 3V;
IOUT = 3A. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient
temperature.
LX8385x-xx
Parameter
Symbol
Test Conditions
Units
Min
Max
LX8385-33 / 8385A-33 / 8385B- (3.3V FIXED)(CONTINUED)
`
`
Maximum Output Current
IOUT(MAX)
VIN < 7V
3
5
0.3
A
%
%
Temperature Stability (Note 3)
Long Term Stability (Note 3)
ΔVOUT(T)
ΔVOUT (t) TA=125°C, 1000 hours
1
RMS Output Noise (% of VOUT
(Note 3)
)
VOUT (RMS) TA=25°C, 10Hz < f < 10kHz
003
%
LX8385-05 / 8385A-05 / 8385B-05 (5.0V FIXED)
VIN=7V, IOUT=0mA, TAC
4.950
4.900
4.960
4.950
5.00
5.00
5.00
5.00
2
5.050
5.100
5.040
5.050
10
V
V
Output Voltage
(Note 4)
LX8385/85A-05
7V < VIN < 10V, 0mA < IOUA, P <
VIN=7V, IOUT=0mA, TA=25°C
VOUT
V
LX8385B-05
7V < VIN < 10V, 0< 3A, AX
V
Line Regulation (Note 2)
Load Regulation (Note 2)
ΔVOUT(VIN) 7V < VIN < 10
ΔVOUT
mV
VIN=7V, 0mA
5
25
mV
(IOUT
)
ΔVOUT
(Pwr)
Thermal Regulation
TA=, 20ms
0.01
0.02
% / W
Ripple Rejection (Note 3)
Quiescent Current
OUT=100antalum), IOUT=3A
UT < MAX), 4.75V < VIN < 10V
ΔVOUT=1%, T < IOUT(MAX)
60
83
4
dB
mA
V
IQ
10
1.5
1.3
1.2
1.1
3.5
0.25
0.3
Dropout Voltage
LX8385-33
LX8385A-33
VOUT=1%, IOUT < IOUT(MAX)
V
Maximum Output Current
< 10V
3
A
Temperature Stability
Long Term Stabi
%
%
Δt) TA=125°C, 1000 hours
1
RMS Output N
(Note 3)
VOUT (RMS) TA=25°C, 10Hz < f < 10kHz
0.003
%
Note 2
Regulnstant junction temperature, using pulse testing with a low duty cycle. Changes in output
voltage cts are covered under the specification for thermal regulation.
These paramough guaranteed are not tested in production.
Note 3
Note 4
See Maximum Output Current Section
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Page 4
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
APPLICATION NOTES
Power
Supply
Minimum Load
(Larger resistor)
The LX8385/85A/85B Series ICs are easy to use Low-
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.
IN
OUT
LX8385x
Full Load
(Smaller
resistor)
ADJ
RDSON << RL
Use of an output capacitor is REQUIRED with the
LX8385/85A/85B series. Please see the table below for
recommended minimum capacitor values.
10
Star Ground
1 sec
These regulators offer a more tightly controlled reference
voltage tolerance and superior reference stability when measured
against the older pin-compatible regulator types that they replace.
FIGURE 1 - DYNAT AND OUTT TEST
STABILITY
OVERLOAD RECOVERY
The output capacitor is part of the regulator’s frequency
compensation system. Many types of capacitors are available,
with different capacitance value tolerances, capacitance
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.
If a bypass capacitor is connected between the output voltage
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 (aluminum7µF
(tantalum) provide for all cases of bypassing the Apin. If a
ADJ pin bypass capacitor is not used, smaller out ca
values are adequate. The table below shows rended
minimum capacitance values for operation.
Like almost aregulatthe LX8385/85A/85B
regulators are with Safe Operating Area (SOA)
proon. The rcuit mits the regulator's maximum
outpuent to ssively wer values as the input-to-output
voltage rence iBy limiting the maximum output
current, thA circuit keeps the amount of power that is
dissipated in tgulator itself within safe limits for all values of
utput ge within the operating range of the
he LX8385/85A/85B SOA protection system is
e able to supply some output current for all values of
ut voltage, up to the device breakdown voltage.
ome conditions, a correctly operating SOA circuit may
prt 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.
Minimum Cacitor
INPUT
10µF
10µF
OUTP
15µF Tantalum, 100µ
47µ20µF
ADJ
None
15µF
When the power system is started “cold”, both the input and
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.
To ensure ge from e power supply
system under raload conditions, designers
generally use s connected in parallel.
Such an arrangmize the effects of the
parasitic resistancnce (ESL) that are present
in all capacitors. Colutions 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.
The circuit shown in Figure 1 can be used to observe the
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.
Now consider the case where the regulator is supplying
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
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Page 5
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
APPLICATION NOTES (CONTINUED)
OVERLOAD RECOVERY (continued)
IN
voltage across the regulator at the time the short circuit is
removed from the output. If this limited current is not sufficient
to develop the designed voltage across the output resistor, the
voltage will stabilize at some lower value, and will never reach
the designed value. Under these circumstances, it may be
necessary to cycle the input voltage down to zero in order to
make the regulator output voltage return to regulation.
OUT
VOUT
VIN
LX8385x
VREF
R1
R2
ADJ
IADJ
50µA
RIPPLE REJECTION
⎛
R2
⎞
Ripple rejection can be improved by connecting a capacitor
between the ADJ pin and ground. The value of the capacitor
should be chosen so that the impedance of the capacitor is equal
in magnitude to the resistance of R1 at the ripple frequency. The
capacitor value can be determined by using this equation:
VOUT = VREF ⎜1
+ I AD
⎜
⎝
FIGURE 2 - BAC ADJUREGULATOR
LOAD REGUL
1
C =
Bause the 85A/B regulators are three-terminal
devict is noble to vide true remote load sensing.
Load retion wlid by the resistance of the wire
connecting regulator o the load. The data sheet specification
for load regun is measured at the bottom of the package.
side sng is a true Kelvin connection, with the
he output divider returned to the negative side of the
gh it may not be immediately obvious, best load
obtained when the top of the resistor divider, (R1), is
directly to the case of the regulator, not to the load.
llustrated in Figure 3. If R1 were connected to the load,
the effective resistance between the regulator and the load would
be:
(
6.28× FR × R1
)
where:
C
≡
the value of the capacitor in Farads; select
an equal or larger standard value.
the ripple frequency in Hz
FR
R1
≡
≡
the value of resistor R1 in ohms
At a Ripple frequency of 120Hz, with R1= 100Ω:
1
C =
=13.3μF
(
6.28×120Hz×100Ω
)
The closest equal or larger standard value should used, in
this case, 15µF. When an ADJ pin bypass capaor is u
output ripple amplitude will be essentially indepenhe
output voltage. If an ADJ pin bypass capacitor is not , output
ripple will be proportional to the ratio of thut voltage to t
reference voltage:
R2 + R1
R1
⎛
⎜
⎞
⎟
RPeff = R ×
P
⎝
⎠
where:
RP
≡
Actual parasitic line resistance.
VO
M =
When the circuit is connected as shown in Figure 3, the
parasitic resistance appears as its actual value, rather than the
higher RPeff
VREF
where:
M
≡
or the seen when the
ally byed.
.
RP Parasitic Line
Resistance
VR
OUT
IN
For example, t ripple will be:
LX8385x
VIN
= 2
Connect R1 to
V
Case of Regulator
R1
ADJ
Output ripple will be twice as bad as it would be if the ADJ
pin were to be bypassed to ground with a properly selected
capacitor.
RL
Connect R2 to
Load
R2
OUTPUT VOLTAGE
The LX8385/85A/85B ICs develop a 1.25V reference voltage
between the output and the adjust terminal (See Figure 2). By
placing a resistor, R1, between these two terminals, a constant
current is caused to flow through R1 and down through R2 to set
the overall output voltage. Normally this current is the specified
minimum load current of 10mA. Because IADJ is very small and
constant when compared with the current through R1, it
represents a small error and can usually be ignored.
FIGURE 3 - CONNECTIONS FOR BEST LOAD REGULATION
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Page 6
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
APPLICATION NOTES (CONTINUED)
Example
LOAD REGULATION (continued)
Given: VIN
VOUT
=
=
=
=
=
5V
2.5V
1.5A
50°C
Even when the circuit is configured optimally, parasitic
resistance can be a significant source of error. A 20 mil. wide PC
trace built from 1 oz. copper-clad circuit board material has a
parasitic resistance of about 25 milliohms per inch of its length at
room temperature. If a 3-terminal regulator used to supply 2.50
volts is connected by 2 inches of this trace to a load which draws
1.5 amps of current, a 75 millivolt drop will appear between the
regulator and the load. Even when the regulator output voltage is
precisely 2.50 volts, the load will only see 2.43 volts, which is a
3% error. It is important to keep the connection between the
regulator output pin and the load as short as possible, and to use
wide traces or heavy-gauge wire.
The minimum specified output capacitance for the regulator
should be located near the regulator package. If several capacitors
are used in parallel to construct the power system output
capacitance, any capacitors beyond the minimum needed to meet
the specified requirements of the regulator should be located near
the sections of the load that require rapidly-changing amounts of
current. Placing capacitors near the sources of load transients will
help ensure that power system transient response is not impaired
by the effects of trace impedance.
IOUT
TA
RθJT
2.7°C/W for TO-220
Find:
Proper Heat Sink to keep Iemperature
below 125°C.**
Solution: The junction ture is:
TJ = PD (RθJT + + RθSA ) + TA
where: PD
RθJT
≡
Dissipate
mal resice from the junction to
mounting tab of the package.
Therresistance through the
intere between the IC and the
ce on which it is mounted.
(1.0°C/W at 6 in-lbs mounting screw
torque).
Thermal resistance from the mounting
surface to ambient (thermal resistance
of the heat sink).
RθCS
RθSA
≡
To maintain good load regulation, wide traces should be used
on the input side of the regulator, especially between the input
capacitors and the regulator. Input capacitor ESR must be small
enough that the voltage at the input pin does not drolow
VIN(MIN) during transients.
S
Heat Sink Temperature.
TJ
TC
RθJT RθCS RθSA
First, find the maximum allowable thermal resistance of the
TS
TA
VΙΝ(ΜΙΝ) = VOUT + VDROPOUT(MAX)
where: VIN(MIN)
≡ the lowest allowable instantaneous
voltage at the i
heat sink:
TJ − TA
VOUT
≡ the ded for the
power s
RθSA
=
−
(
RθJT + RθCS
)
PD
VDROPOUT(MAX) ≡ the specififor the
ed regu
P = (VIN(MAX)− VOUT )IOUT = (5.0V −2.5V)×1.5A
D
THERMAL CO
P = 3.75W
D
The LX838have internal power and
thermal limitinrotect each device under
overload conditnormal load conditions,
however, maximuature ratings must not be
exceeded. It is impcareful consideration to all
sources of thermal resistfrom junction to ambient. This
includes junction to case, case to heat sink interface, and heat
sink thermal resistance itself.
Junction-to-case thermal resistance is specified from the IC
junction to the back surface of the case directly opposite the die.
This is the lowest resistance path for heat flow. Proper mounting
is required to ensure the best possible thermal flow from this area
of the package to the heat sink. Thermal compound at the case to
heat sink interface is strongly recommended. If the case of the
device must be electrically isolated, a thermally conductive
spacer can be used, as long as its added contribution to thermal
resistance is considered. Note that the case of all devices in this
series is electrically connected to the output.
125°C−50°C
(5.0V − 2.5V)*1.5A
RθSA =16.3°C/W
RθSA
=
−(2.7°C/W +1.0°C/W)
Next, select a suitable heat sink. The selected heat sink must
have RθSA < 3.1°C/W. Thermalloy heatsink 6230B has RθSA
12°C/W.
Finally, verify that junction temperature remains within speci-
fication using the selected heat sink:
=
TJ = 3.75W(2.7°C/W +1.0°C/W +12.0°C/W)+50°C
TJ =109°C
** Although the device can operate up to 150°C junction, it is recommended for long
term reliability to keep the junction temperature below 125°C whenever possible.
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Page 7
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
TYPICAL APPLICATIONS
IN
OUT
(Note A)
VIN
VOUT**
LX8385x
+
IN
OUT
C1*
R1
121Ω 1%
VIN
VOUT
LX8385x
10µF
C2
(Note A)
+
100µF
ADJ
+
R1
10µF
121Ω 1%
ADJ
150µF
R2
1k
C1
10µF*
+
R2
365Ω 1%
* C1 improves ripple rejection.
≈
XC should be R1 at ripple
frequency.
* Needed if derom filtpacitors.
⎞
⎟
⎠
FIGURE 4 - IMPROVING RIPPLE REJECTION
* = 1.25
R1
FIGURE 1.2V - 8V ADJUSTABLE REGULATOR
IN
VIN
5V
LX83
(note A)
+
121Ω
10µF
1%
ADJ
+
1k
100µF
N3904
365Ω
TT
1%
1k
FIGURE 6 - 5V REGULATOR W ITH SHUTDOW N
IN
OUT
3.3V
VIN
LX8385x
Min. 15µF Tantalum or
10µF Tantalum or
100µF Aluminum
100µF Aluminum capacitor. May
be increased without limit. ESR
must be less than <400mΩ .
ADJ
FIGURE 7 - FIXED 3.3V OUTPUT REGULATOR
Note A: VIN(MIN) = (IntendedVOUT) + VDROPOUT(MAX)
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Integrated Products Division
Page 8
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
PACKAGE DIMENSIONS
3-Pin Plastic TO-220
P
B
S
MILLIMETERS
INCHES
Dim
F
T
Q
MIN
14.22
9.65
3.56
0.51
3.53
MAX
15.88
10.67
4.83
14
9
MIN
MAX
0.625
0.420
0.190
0.045
0.161
A
40
20
0.139
U
B
C
D
A
F
C
1
2
3
G
H
J
K
2.54 BSC
0.100 BSC
R
H
6.35
1.14
0.250
0.045
0.580
0.050
1
0.012
0.500
0.045
73
K
.27
D
N
Q
5.08 TYP
0.200 TYP
.54
03
1.14
5.84
0.508
3.05
2.92
1.40
6.86
1.14
0.100
0.080
0.045
0.230
0.020
0.120
0.115
0.055
0.270
0.045
L
J
G
N
3-Pin Plastic TO-263
DD
I
A
MILLIMETERS
INCHES
Dim
MIN
10.03
8.51
4.19
1.14
0.330
1.19
2.41
2.29
–
MAX
10.67
9.17
4.59
1.40
0.51
1.34
2.66
2.79
1.65
0.25
15.87
MIN
0.395
0.335
0.165
0.045
0.013
0.047
0.095
0.090
–
MAX
0.420
0.361
0.181
0.055
0.020
0.053
0.104
0.110
0.065
0.010
0.625
A
B
C
D
E
F
G
H
I
B
K
M
N
H
E
F
G
J
0
0
K
M
N
14.60
0.575
7°
3°
7°
3°
0° -8°
J
Seating Plane
Note: Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006”) on any side. Lead dimension shall
not include solder coverage.
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Integrated Products Division
Page 9
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
PACKAGE DIMENSIONS
3-Pin Plastic TO-252
DT
P
U
J
MILLIMETERS
INCHES
Dim
MIN
6.47
5.97
2.16
0.68
0.38
0.63
2
9.55
.20
MAX
6.73
6.23
2.42
4
0.8
2.42
1.10
5
.70
9.81
5.46
MIN
MAX
0.265
0.245
.095
0.037
0.025
0.035
0.095
0.043
0.045
0.106
0.386
0.215
A
B
C
D
E
F
G
H
I
85
27
0.015
0.025
.085
0.033
0.035
0.096
0.376
0.205
G
F
N
A
W
L
Q
O
V
0.23
K
L
Q
R
U
V
W
X
7.0°
45°
7.0°
0.51
0.51
4.19
0.76
0.48
0.51
0.77
0.77
4.45
1.02
0.74
0.77
0.020
0.020
0.165
0.030
0.019
0.020
0.030
0.030
0.175
0.040
0.029
0.030
M
H
C
R
45°
B
E
X
1.44
0
1.70
0.10
0.057
0
0.067
0.004
K
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Page 10
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8385x-xx
®
3A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
NOTES
PRODUCTION DATA – Information contained in this document is proprietary to
Microsemi and is current as of publication date. This document may not be modified in
any way without the express written consent of Microsemi. Product processing does not
necessarily include testing of all parameters. Microsemi reserves the right to change the
configuration and performance of the product and to discontinue product at any time.
Copyright © 2000
Rev. 2.0b, 2005-10-25
Microsemi Inc.
Integrated Products Division
Page 11
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
相关型号：
©2020 ICPDF网 联系我们和版权申明