LX8585-XX_05 [MICROSEMI]
4.6A Low Dropout Positive Regulators; 4.6A低压差正稳压器
| 型号： | LX8585-XX_05 |
| 厂家： | 
Microsemi |
| 描述： | 4.6A Low Dropout Positive Regulators |
| 文件： | 总10页 (文件大小：272K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
KEY FEATURES
DESCRIPTION
Three Terminal Adjustable or
Fixed Output
Guaranteed < 1.2V headroom
@ 4.6A (LX8585A)
Guaranteed < 1.4V headroom
@ 4.6A (LX8585)
Guaranteed < 1.3V Headroom
@ 3A
The LX8585/85A Series ICs are short-circuit current. On-chip thermal
low dropout three-terminal regulators limiting provides protection against any
with a minimum of 4.6A output possible overload that would create
current. Pentium® Processor and excessive junction temperatures. The
Power PCTM applications requiring LX8585/85A family is available in both
fast transient response are ideally through-hole
and
surface-mount
suited for this product family. The versions of the industry standard 3-pin
LX8585A is guaranteed to have < TO-220 / TO-263 power packages.
Output Current of 4.6A
Minimum
1.2V at 4.6A, while the LX8585 are
The
LX1431
Programmable
Fast Transient Response
1% Voltage Reference Initial
Accuracy
Output Short Circuit Protection
Built-In Thermal Shutdown
specified for 1.4V, making them ideal Reference and LX8585A Series
to provide well regulated outputs of products offer precision output voltage
2.5V to 3.6V using a 5V input supply. and are ideal for use in VRE
Fixed versions are also available and applications (see application below).
specified in the Available Options For higher current applications, see the
table below. Current limit is trimmed LX8584 data sheet.
above 4.6A to ensure adequate output
current and controlled
APPLICATIONS
Pentium Processor Supplies
Power PC Supplies
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
Microprocessor Supplies
Low Voltage Logic Supplies
Battery Powered Circuit
Post Regulator for Switching
Supply
PRODUCT HIGHLIGHT
THE APPLICATION OF THE LX8585A & LX1431 IN A
75 & 166 MHZ P54C PROCESSORSUSING 5V CACHE
V
4.6A
CYRIX® 6x86™ Supplies
AMD-K5™ Supplies
O
PLACE IN µP SOCKET CAVITY
3
2
(See Table Below)
VIN
VOUT
5V
2x
LX8585A
330 µ F, 6.3V
1k Ω
Low ESR
Oscon Type
from Sanyo
Available Options Per Part Number
ADJ
1
0.01 µF
1kΩ
Part #
Output Voltage
Adjustable
1.5V
100 µ F x 6
10V
250pF
2
LX8585/85A-00
LX8585/85A-15
LX8585/85A-33
AVX TYPE
TPS
1
1k
0.1%
µP
Load
COL
3
8
3.3V
V+
220 µF
10V
REF
Low ESR
Sanyo
from
LX1431
2.84k Ω
0.1%
21k
1%
Other voltage options may be available.
Please contact factory for details.
1µ F x 10
SMD
0.1 µF
50V
JP1
SGND FGND
5
6
VOUT
3.50
3.38
JP1
Short
Open
Typical Application
120 / 166MHz, VRE, 5V Cache
75/90/100/133MHz, STND, 5V Cache
Thick traces represent high current traces which must be low resistance / low inductance
traces in order to achieve good transient response.
PACKAGE ORDER INFO
Plastic TO-220
3-Pin
Plastic TO-263
3-Pin
Dropout
Voltage
P
DD
TA (°C)
RoHS Compliant
RoHS Compliant
Transition DC: 0543
Transition DC: 0535
1.4V
1.2V
LX8585-xxCP
LX8585A-xxCP
LX8585-xxCDD
LX8585A-xxCDD
0 to 125
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8585-15CDD-TR)
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Integrated Products Division
Page 1
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
ABSOLUTE MAXIMUM RATINGS
PACKAGE PIN OUT
TAB is GND
Power Dissipation....................................................................................Internally Limited
Input Voltage .................................................................................................................10V
Input to Output Voltage Differential..............................................................................10V
Maximum Operating Junction Temperature .............................................................. 150°C
Storage Temperature Range.........................................................................-65°C to 150°C
Peak Package Temp. for Solder Reflow (40 seconds max. exposure)............ 260°C (+0 -5)
3
2
1
VIN
VOUT
ADJ/GND*
P PACKAGE
(Top View)
TAB is GND
Note: 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.
VIN
3
2
1
VOUT
ADJ / GND*
THERMAL DATA
DD PACKAGE
(Top View)
PlasticTO-220 3-Pin
P
* Pin 1 is GND for fixed voltage versions
RoHS 100% Matte Tin Lead Finish
THERMAL RESISTANCE-JUNCTION TO TAB, θJT
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
3.0°C/W
60°C/W
Plastic TO-263 3-Pin
DD
THERMAL RESISTANCE-JUNCTION TO TAB, θJT
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
3.0°C/W
60°C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the
above assume no ambient airflow.
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Page 2
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 70°C except where
otherwise noted and the following test conditions:.
LX8585/85A
Parameter
Symbol
Test Conditions
Units
Min
Typ
Max
`
LX8585-00 / 8585A-00 (ADJUSTABLE)
Reference Voltage
IOUT = 10mA, TA = 25°C
10mA < IOUT < 4.6A, 1.5V < (VIN – VOUT), VIN < 7V,
P < PMAX
1.238
1.225
1.250
1.250
1.262
1.275
VREF
V
Line Regulation (Note 2)
Load Regulation (Note 2)
Thermal Regulation
∆VREF(VIN) IOUT = 10mA, 1.5V < (VIN – VOUT), VIN < 7V
VREF(IOUT VIN – VOUT = 3V, 10mA < IOUT < 4.6V
∆VOUT (Pwr) TA = 25°C, 20ms pulse
0.035
0.1
0.01
0.20
0.5
0.02
%
%
%/W
)
V
OUT = 3.3V, f = 120Hz, COUT = 100µF Tantalum,
Ripple Rejection (Note 3)
VIN = 5V, CADJ = 10µF,
TA = 25°C, IOUT = 4.6V
60
83
dB
Adjust Pin Current
IADJ
55
100
5
µA
µA
10mA < IOUT < 4.6A, 1.5V < (VIN – VOUT),
VIN < 7V
Adjust pin Current Change
∆IADJ
0.2
∆VREF = 1%, IOUT = 4.6A
∆VREF = 1%, IOUT = 3A
∆VREF = 1%, IOUT = 4.6A
VIN < 7V
1.2
1.1
1.1
2
4.6
0.25
0.3
1.4
1.3
1.2
10
6
LX8585
LX8585A
Dropout Voltage
∆V
V
Minimum Load Current
IOUT(MIN)
IOUT(MAX)
∆VOUT(t)
∆VOUT(t)
mA
A
%
Maximum Output Current (Note 4)
Temperature Stability (Note 3)
Long Term Stability (Note 3)
RMS Output Noise
1.4V < (VIN – VOUT), VIN < 7V
TA = 125°C, 1000hrs
1
%
VOUT(RMS)
TA = 125°C, 10Hz < f < 10kHz
0.003
%
(% of VOUT)(Note 3)
`
LX8585-15 / 8585A-15 (1.5V FIXED)
VIN = 5V, IOUT = 0mA, TA = 25°C
4.75 < VIN < 10V, 0mA < IOUT < 7A, TA = 25°C, P
< PMAX
1.485
1.470
1.50
1.50
1.515
1.530
Output Voltage (Note 4)
VOUT
V
4.75 < VIN < 7V
4.75V < VIN < 10V
1
1
3
5
mV
Line Regulation (Note 2)
∆VOUT (VIN)
Load Regulation (Note 2)
Thermal Regulation (Note 3)
∆VOUT(IOUT
)
VIN = 5V, 10mA < IOUT < IOUT(MAX)
2.5
0.01
7
0.02
mV
% / W
∆VOUT(Pwr) TA = 25°C, 20ms pulse
COUT = 100µF (Tantalum), IOUT = 4.6A,
Ripple Rejection (Note 3)
Quiescent Current
65
83
dB
TA = 25°C
IQ
0mA < IOUT < IOUT(MAX), 4.75V < VIN < 10V
∆VOUT = 1%, IOUT < IOUT(MAX), VIN - VOUT < 7V
∆VOUT = 1%, IOUT < 3A, VIN - VOUT < 7V
∆VOUT = 1%, IOUT < IOUT(MAX), VIN - VOUT < 7V
4
10
1.4
1.3
1.2
mA
1.2
1.1
1.1
0.25
0.3
LX8585-15
Dropout Voltage
∆V
V
LX8585A-15
Temperature Stability (Note 3)
Long Term Stability (Note 3)
RMS Output Noise (% of
VOUT)(NOTE 3)
∆VOUT(T)
∆VOUT(t)
%
%
TA = 125°C, 1000hrs
1
VOUT(RMS)
TA = 25°C, 10Hz < f < 10kHz
0.003
%
Note 2: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating
effects are covered under the specification for thermal regulations.
Note 3: These parameters, although guaranteed, are not tested in production.
Note 4: IOUT(MAX) is measured under the condition that VOUT is forced below its nominal value by 100mV.
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Integrated Products Division
Page 3
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
APPLICATION CIRCUITS
LX8585/85A
OUT
LX8585/85A
OUT
(Note A)
VIN
5V
VOUT
IN
VIN
(Note A)
IN
VOUT**
R1
121Ω
1%
ADJ
ADJ
R1
121Ω
10µF
150µF
C2
100µF
C1*
10µF
R2
365Ω
1%
R2
1k
C1
* C1 improves ripple rejection.
C should be≈ R1 at ripple
frequency.
10µF*
X
Figure 1 – Improving Ripple Rejection
Needed if device is far from filter capacitors.
R2
R1
** VOUT = 1.25V 1 +
Figure 2 – 1.2V – 8V Adjustable Regulator
LX8585/85A
OUT
VIN
(Note A)
IN
5V
ADJ
121Ω
1%
100µF
10µF
1k
TTL
Output
2N3904
365Ω
1%
1k
Figure 3 – 5V Regulator With Shutdown
LX8585-33/85A-33
IN
OUT
V
3.3V
IN
GND
10µF Tantalum
or 100µF Aluminum
Min. 15µF Tantalum or
100µF Aluminum capacitor.
May be increased without
limit. ESR must be less
than 50mΩ.
Figure 4 – Fixed 3.3V Output Regulator
Note A: VIN(MIN) = (Intended VOUT) + (VDROPOUT(MAX)
)
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Integrated Products Division
Page 4
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
APPLICATION NOTE
Minumum Load
(Larger resistor)
The LX8585/85A 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.
Power Supply
IN
OUT
LX8585/85A
Full Load
(Smaller resistor)
ADJ
RDSON<< RL
1 sec
10ms
Use of an output capacitor is REQUIRED with the LX8585/85A
series. Please see the table below for recommended minimum
capacitor values.
Star Ground
Figure 5 – Dynamic Input & Output Test
OVERLOAD RECOVERY
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.
Like almost all IC power regulators, the LX8585/85A 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
LX8585/85A 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.
STABILITY
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 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 (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 stable operation
Under some conditions, a correctly operating SOA circuit may
prevent a power supply system from returning to regulated
operation 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.
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.
Input
Output
Adj
10µF 15µF Tantalum, 100µF Aluminum
None
10µF 47µF Tantalum, 220µF Aluminum
15µF
To ensure good transient response from the power supply 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.
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 voltage
across the regulator at the time the short circuit is removed from
the output.
The circuit shown in Figure 5 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 undershoot, can be compared quickly in order to
develop an optimum solution.
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Page 5
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
APPLICATION NOTE
OVERLOAD RECOVERY (continued)
LX8585/85A
OUT
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.
IN
VIN
VOUT
ADJ
VREF
R1
R2
IADJ
50µA
RIPPLE REJECTION
R2
R1
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 +
+ IADJ R2
Figure 6 – Basic Adjustable Regulator
LOAD REGULATION
C = 1 / (6.28 * FR * R1)
where: C ≡ the value of the capacitor in Farads; select an equal
or larger standard value.
Because the LX8585/85A regulators are three-terminal devices,
it is not possible to provide true remote load sensing. Load
regulation will be limited by the resistance of the wire connecting
the regulator to the load. The data sheet specification for load
regulation is measured at the bottom of the package. Negative
side sensing is a true Kelvin connection, with the bottom of the
output divider returned to the negative side of the load. Although
it may not be immediately obvious, best load regulation is
obtained when the top of the resistor divider, (R1), is connected
directly to the case of the regulator, not to the load. This is
illustrated in Figure 7. If R1 were connected to the load, the
effective resistance between the regulator and the load would be:
FR ≡ the ripple frequency in Hz
R1 ≡ the value of resistor R1 in ohms
At a ripple frequency of 120Hz, with R1 = 100Ω:
C = 1 / (6.28 * 120Hz * 100Ω) = 13.3μF
The closest equal or larger standard value should be used, in this
case, 15μF.
When an ADJ pin bypass capacitor is used, output ripple
amplitude will be essentially independent of the output voltage. If
an ADJ pin bypass capacitor is not used, output ripple will be
proportional to the ratio of the output voltage to the reference
voltage:
R2 + R1
⎛
⎜
⎝
⎞
⎟
⎠
RPeff = RP
*
R1
M = VOUT/VREF
where: RP ≡ Actual parasitic line resistance.
where: M ≡ a multiplier for the ripple seen when the ADJ pin is
optimally bypassed.
When the circuit is connected as shown in Figure 7, the parasitic
resistance appears as its actual value, rather than the higher RPeff
VREF = 1.25V.
For example, if VOUT = 2.5V the output ripple will be:
M = 2.5V/1.25V= 2
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.
RP
Parasitic
LX8585/85A
Line Resistance
OUT
IN
VIN
ADJ
Connect
R1 to Case
of Regulator
OUTPUT VOLTAGE
The LX8585/85A ICs develop a 1.25V reference voltage
between the output and the adjust terminal (See Figure 6). 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.
R1
R2
RL
Connect
R2
to Load
Figure 7 – Connections For Best Load Regulation
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Page 6
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
APPLICATION NOTE
can be used, as long as its added contribution to thermal
LOAD REGULATION (continued)
resistance is considered. Note that the case of all devices in this
series is electrically connected to the output.
Even when the circuit is configured optimally, parasitic
resistance can be a significant source of error. A 100 mil (2.54
mm) wide PC trace built from 1 oz. copper-clad circuit board
material has a parasitic resistance of about 5 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 5 amps of current, a 50 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 2.45
volts, which is a 2% 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.
Example
Given: VIN = 5V
VOUT = 2.8V, IOUT = 5.0A
Ambient Temp. TA = 50°C
RΘJT = 2.7°C/W for TO-220
300 ft/min airflow available
Find:
Proper Heat Sink to keep IC’s junction temperature
below 125°C.**
Solution: The junction temperature is:
TJ = PD (RΘJT + RΘCS + RΘSA) + TA
Where: PD ≡ Dissipated Power
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.
RΘJT ≡ Thermal resistance from the junction to the
mounting tab of the package
RΘCS ≡ Thermal resistance through the interface
between the IC and the surface on which it is mounted.
(1.0°C/W at 6 in-lbs mounting screw torque).
RΘSA ≡ Thermal resistance from the mounting surface
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 drop below VIN
(MIN) during transients.
to ambient (thermal resistance of the heat sink).
TS ≡ heat sink temperature.
TJ
TC
TS
TA
R
R
R
JT
CS
SA
VIN (MIN) = VOUT + VDROPOUT (MAX)
First, find the maximum allowable thermal resistance of the heat
sink:
where: VIN (MIN) ≡ the lowest allowable instantaneous voltage at
the input pin.
TJ − TA
VOUT ≡ the designed output voltage for the power supply
system.
RΘSA
=
− (RΘJT + RΘCS
)
PD
VIN(MAX) − VOUT
= 11.0W
VDROPOUT
installed regulator.
≡ the specified dropout voltage for the
(MAX)
PD
=
(
)
IOUT = (5.0V − 2.8V) * 5.0A
THERMAL CONSIDERATIONS
The LX8585/85A regulators have internal power and thermal
limiting circuitry designed to protect each device under overload
conditions. For continuous normal load conditions, however,
maximum junction temperature ratings must not be exceeded. It is
important to give careful consideration to all sources of thermal
resistance from 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
125°C − 50°C
RΘSA
=
− (2.7°C/W + 1.0°C/W)
(5.0V − 2.8V) * 5.0A
= 3.1°C/W
Next, select a suitable heat sink. The selected heat sink must
have RΘSA < 3.1°C/W. Thermalloy heatsink 6296B has RΘSA
3.0°C/W with 300ft/min airflow.
Finally, verify that junction temperature remains within
specification using the selected heat sink:
=
T = 11W(2.7°C/W + 1.0°C/W + 3.0°C/W) + 50°C = 124°C
J
**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 © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Page 7
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
PACKAGE DIMENSIONS
3-Pin Plastic TO-220
P
B
S
MILLIMETERS
INCHES
Dim
MIN
14.22
9.65
3.56
0.51
3.53
MAX
15.88
10.67
4.83
1.14
4.09
MIN
MAX
0.625
0.420
0.190
0.045
0.161
F
T
Q
A
B
C
D
F
0.560
0.380
0.140
0.020
0.139
U
A
G
H
J
K
L
2.54 BSC
0.100 BSC
6.35
1.14
0.250
0.045
0.580
0.050
C
0.30
12.70
1.14
0.012
0.500
0.045
1
2
3
14.73
R
H
1.27
N
Q
R
S
T
5.08 TYP
0.200 TYP
2.54
2.03
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
K
D
U
Note:
L
J
1. 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.
G
N
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Page 8
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A Low Dropout Positive Regulators
TM
PRODUCTION DATA SHEET
PACKAGE DIMENSIONS
3-Pin Plastic TO-263
DD
I
A
MILLIMETERS
INCHES
D
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
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
J
0.395
0.335
0.165
0.045
0.013
0.047
0.095
0.090
–
C
B
K
M
N
H
0
0
K
M
N
14.60
0.575
E
F
7°
3°
7°
3°
G
Note:
1. 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.
0° -8°
J
Seating Plane
Copyright © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Page 9
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8585-xx / LX858A-xx
®
4.6A 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 © 1997
Rev. 2.2a, 2005-11-10
Microsemi
Integrated Products Division
Page 10
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
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