Microsemi LX8819 Dual channel 1a low dropout regulator Datasheet

LX8819
®
TM
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
KEY FEATURES
DESCRIPTION
Voltages (typically ±1% of its specified
value) while the Bipolar output
transistor has a low dropout voltage
even at full output current (VDO < 1.25V
typical @ 1A).
Thermal and Short Circuit Current
Protection are integrated on-chip and
operate independently for each of the
regulator output.
The LX8819 regulator is stable with
a low-value output capacitor (typically
2.2µF on the outputs) allowing the
designers flexibility in external
component selection.
Microsemi’s S-PAK and D-PAK
power packages enable maximum
power dissipation and ease of assembly
using surface mount technology.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
ƒ Two Independent Regulated
Outputs
ƒ Accurate Output Voltages
ƒ Typical Dropout of 1.25V at 1A
and 1.1V at 500mA
ƒ Independent Thermal and
Current Limit Protection
ƒ Low Profile 5 Lead SMT Power
Package
ƒ Low Tolerance Load
Regulation
ƒ Wide DC Supply Voltage of
3.5V to 10V
ƒ Loop Stability Independent of
Output Capacitor Type
WWW . Microsemi .C OM
The LX8819 is a dual channel
positive-voltage linear regulator. This
dual regulator has one fixed output
coupled with an adjustable output.
Each channel features a low dropout
and a high accuracy.
The LX8819 provides designers
with a flexible power management
solution, minimal printed circuit board
area, and shorter design cycles.
Each channel can supply up to one
amp independently with a regulator
design optimized for system efficiency
by consuming minimal ground current
while directing quiescent current to
the load.
The LX8819 features on-chip
trimming of the internal voltage
reference enabling precise output
APPLICATIONS
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
5V to 3.3V / ADJ Regulators
Hard Disk Drives, CD-ROMs
ADSL and Cable Modems
Battery Charging Circuits
Instrumentation
PC Peripherals
PRODUCT HIGHLIGHT
V IN = 5V
VIN
VOUT2
10 F
22 F
VOUT2 = 3.3V/2.5V @ 1A
8819
GND
VOUT1 = 1.8V @ 1A
VOUT1
10 F
ADJ
221
499
TJ (°C)
0 to 125
Output V1 Output V2
(Pin 5)
(Pin 4)
Adj.
Adj.
3.3
2.5
DF
Plastic S-PAK
5 pin
DT
LX8819
PACKAGE ORDER INFO
Plastic D-PAK
5-Pin
RoHS Compliant
Transition DC: 0515
LX8819-33CDF
LX8819-25CDF
LX8819-33CDT
LX8819-25CDT
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8819-33CDT-TR)
Copyright © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX8819
®
TM
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
ABSOLUTE MAXIMUM RATINGS
PACKAGE PIN OUT
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.
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Input Voltage (VIN)......................................................................................13.5V
Load Current (Internally Limited) .....................................................................1A
Power Dissipation ......................................................................Internally Limited
Short-Circuit Protection .......................................................................... Indefinite
Operating Temperature Range ......................................................... 0°C to 150°C
Maximum Operating Junction Temperature ................................................ 150°C
Storage Temperature Range...........................................................-65°C to 150°C
Lead Temperature (Soldering 180 seconds) ................................................ 235°C
RoHS Peak Package Solder Reflow Temperature
(40 second maximum exposure) ..................................................... 260°C (+0, -5)
DF PACKAGE
(Top View)
RoHS 100% Matte Tin Lead Finish
TAB is GND
VOUT2
VOUT1
GND
ADJ
VIN
THERMAL DATA
DF
Plastic S-PAK 5-Pin
THERMAL RESISTANCE-JUNCTION TO CASE, θJC
5°C/W
30°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
DT
DT PACKAGE
(Top View)
Plastic D-PAK 5-Pin
THERMAL RESISTANCE-JUNCTION TO CASE, θJC
6°C/W
32°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
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.
θJA can vary from 25°C/W to > 40°C/W depending on mounting technique. (See Application Notes
Section: Thermal considerations)
FUNCTIONAL PIN DESCRIPTION
Name
Description
VIN
Positive unregulated supply input for the regulator – Bypass to GND with at least 2.2µF capacitance having low
ESR for good transient response.
Adjustable regulator feedback input – The output voltage can be set by two external resistors with the following
relationship:
⎛
VOUT1 = VREF ⋅ ⎜⎜ 1 +
ADJ
⎝
R1 ⎞
⎟
+ I ADJ ⋅ R1
R 2 ⎟⎠
GND
Common terminal for ground reference – The input and output bypass capacitors should be connected to
this pin. In addition the tab on the S-Pak package and pin 3 are also used for heat sinking the device.
VOUT1
Adjustable regulator output (Regulator #1) – It is recommended to bypass to GND with at least 2.2µF. Size your
output capacitor to meet the transient loading requirement. If you have a very dynamic load, a lower ESR
capacitor will improve the response to these load steps.
VOUT2
Fixed regulator output (Regulator #2) – It is recommended to bypass to GND with at least 2.2µF. Size your
output capacitor to meet the transient loading requirement. For dynamic loads, a lower ESR capacitor will
improve the response to these load steps.
Copyright © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
PACKAGE DATA
where R1 is the resistor connected between VOUT1 and ADJ, and R2 is the resistor connected between ADJ and
GND.
LX8819
®
TM
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
RECOMMENDED OPERATING CONDITIONS
Symbol
Input Voltage - 3.3V
Input Voltage - 2.5V < 200mA Load
Output Voltage (Adjustable)
Load Current (Each Output)1
Input Capacitor (VIN to GND)
Output Capacitor (VOUTx to GND)2
Note
VIN
VOUT
IOUT
CIN
COUT
Min
4.5
3.5
LX8819
Typ
0
2.2
1.0
Max
10
10
5
1000
20
10
Units
V
V
V
mA
µF
µF
1: Care should be taken so as to not exceed the thermal dissipation capability of the package
2: Size your output capacitor to meet the transient loading requirement. If you have a very dynamic load, a lower ESR and larger value
capacitor will improve the response to these load steps.
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Parameter
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 125°C except where
otherwise noted and with the following test conditions: VIN = 5V, IOUT = 10mA, CIN= 10µF (Tantalum), COUT = 4.7µF (Tant.), and TJ = TA
using low duty cycling methods.
Parameter
`
Min
LX8819
Typ
Max
Units
VREF
∆VREF(VIN)
∆VREF(IOUT)
∆V
IOUT (MAX)
IL
IADJ
5mA < IOUT1 < 1A, 4.75V < VIN < 5.5V
3.75V < VIN < 5.5V, IOUT1 = 5mA
5mA < IOUT1 < 1A, VIN = 4.75V
1.225
IOUT1 = 1A, ∆V1 = -1%
1.0
Note 3
1.25
1.5
0.18
1.3
1.4
2
-0.12
1.275
V
6
mV
0.36 %VOUT
1.46
V
A
3
mA
-1
µA
3.30
2.5
6
6
1.25
3.383
2.562
8
12
1.41
1.25
FIXED OUTPUT (OUTPUT 2)
Output Voltage – LX8819-33
Output Voltage – LX8819-25
Line Regulation
Load Regulation
Dropout Voltage
Current Limit
Minimum Load Current
`
Test Conditions
ADJUSTABLE OUTPUT (VOUT1)
Reference Voltage
Line Regulation
Load Regulation
Dropout Voltage
Current Limit
Minimum Load Current
Adjust Pin Bias Current
`
Symbol
5mA < IOUT2 < 1A, 4.75V < VIN < 5.5V
5mA < IOUT2 < 0.2A, 3.75V < VIN < 5.5V
∆VOUT(VIN) 4.75V < VIN < 5.5V, IOUT2 = 5mA
∆VOUT(IOUT) 5mA < IOUT2 < 1A, VIN = 4.75V
IOUT2 = 1A, ∆V2 = -1%
∆V
IOUT2 = 0.2A, ∆V2 = -1%
IOUT (MAX)
IOUT
VOUT
3.217
2.437
1.0
1.4
0
V
mV
mV
V
V
A
mA
ENTIRE REGULATOR
IQ
VIN Under Voltage Lockout
Threshold
VOUT Rise Time for VIN
Switched On
Ripple Rejection
RMS Output Noise
Thermal Shutdown
Note
UVLO
VIN < 5.5V, IOUT1 = 5mA, IOUT2 = 5mA
VIN < 5.5V, IOUT1 = 1A, IOUT2 = 1A
-3.3 Voltage Rising
-2.5 Voltage Rising @ 25 °C
VOUT(tR)
PSRR
VOUT (RMS)
TJSD
f=120Hz, VIN = 5V
10Hz < f < 10kHz
2.6
3.5
2.5
2.5
4.2
5
4.5
3.6
80
300
60
150
75
0.003
165
mA
V
µs
dB
%VOUT
°C
3: Minimum load current is defined as the amount of output current required to maintain regulation. , The external resistor divider current can be
included in this requirement.
Copyright © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
PACKAGE DATA
Quiescent Current
LX8819
®
TM
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
SIMPLIFIED BLOCK DIAGRAM
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VIN
1
V
5
C1
10 F
OUT2
(Fi x e d )
BIAS
C2
10 F
+
-
VIN
1.25V
VREF
V
4
OUT1
(Ad j u s ta b l e )
R1
GND
C3
10 F
2
+
-
R2
3
⎛
R ⎞
VOUT1 = VREF ⋅ ⎜⎜1 + 1 ⎟⎟ + IADJ ⋅ R1
⎝ R2 ⎠
No te : Ap p l i c a ti o n c i rc u i t a b o v e u s i n g c e ra m i c c a p a c .i to rs R1 a n d R2 u s e d wi th a d j u s ta b l e v e rs i o n o n l y .
Figure 1 – Simplified Block Diagram
ELECTRICALS
Copyright © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
LX8819
TM
®
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
APPLICATION INFORMATION
INPUT CAPACITOR
To improve load transient response and noise rejection
an input bypass capacitor of at least 2.2µF is required.
Generally it is recommended that a 20µF ceramic/tantalum
or 22µF electrolytic capacitor be used.
OUTPUT CAPACITOR
The LX8819 regulator requires output capacitors
connected between each voltage output and ground to
stabilize the internal control loop.
Many types of
capacitors, with different capacitance values, tolerances,
temperature coefficients, and equivalent series resistance
are available for use with the LX8819. It is recommended
that a minimum of 4.7µF be used at each voltage output.
To ensure good transient response from the power
supply system under rapidly changing current load
conditions, designers generally use additional 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. The regulator has been tested stable with
capacitor ESR’s in the range of 50mΩ to 2Ω. It is
generally best to use the same type of capacitors for both
input and output bypassing.
MINIMUM LOAD REQUIREMENT
The LX8819 has a minimum load requirement for
proper output regulation.
This minimum current is
specified at 0mA for the fixed output and 2mA for the
adjustable output regulator.
Copyright © 2003
Revision 1.0a, 4/29/2005
VOUT2
LX8819
VOUT1
R1
ADJ
IADJ
1 A
⎛ R ⎞
VOUT1 = VREF ⋅ ⎜⎜1 + 1 ⎟⎟ + IADJ ⋅ R 1
⎝ R2 ⎠
VREF
R2
Figure 2 – Basic Regulator Circuit
TEMPERATURE PROTECTION
The thermal protection shuts the LX8819 down when the
junction temperature exceeds 140°C. Each output has
independent thermal shutdown capability. Exposure to
absolute maximum rated conditions for extended periods
may affect device reliability (See Thermal Considerations
below).
CURRENT LIMIT PROTECTION
The LX8819 includes over current protection. When the
output load current exceeds 1.4A (typical) the current limit
protection circuit forces the regulator to decrease the output
current in order to maintain safe levels.
THERMAL CONSIDERATIONS
Thermal shutdown protection circuitry protects the
integrated circuit from thermal overload caused from a rise
in junction temperature during excessive power dissipation
conditions. This means of protection is intended for fault
protection only and not as a means of current or power
limiting during normal application usage.
Proper thermal evaluation should be done to ensure that
the junction temperature (TJ) does not exceed its maximum
rating. Continuous operation at the maximum TJ of 150°C
can impact reliability.
Due to variation in individual device electrical
characteristics and thermal resistance, the built in thermal
overload protection may be activated at power levels
slightly above or below the rated dissipation. Also, peak
output power should be considered for each individual
output.
Total power dissipation for the regulator can be
calculated using the following equation:
PD = (VIN(MAX) − VOUT1 ) ⋅ IOUT1 + (VIN(MAX) − VOUT2 ) ⋅ IOUT2
(Note: Power dissipation resulting from quiescent (ground)
current is negligible and ignored)
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
APPLICATIONS
ADJUSTABLE OUTPUT VOLTAGE
The LX8819 develops a 1.25V reference voltage
between the adjust terminal and ground (See Figure 2). By
placing a resistor, R2, between these two terminals, a
constant current is caused to flow through R1 and down
through R2 to set the overall output voltage. Because IADJ
is very small and constant when compared with the current
through R2, it represents a small error and can usually be
ignored.
VIN
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DESCRIPTION
The LX8819 is part of a family of Dual LDO (Low
Drop-Out) linear regulators in Microsemi’s S-PAK power
package which offer maximum power dissipation in a low
profile surface mount technology. The family includes a
combination of fixed and adjustable versions. Each
channel can supply up to one amp independently with a
regulator design optimized for system efficiency by
consuming minimal ground current and directing quiescent
current to the load.
LX8819
®
TM
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
APPLICATION INFORMATION
THERMAL CALCULATION EXAMPLE
Given the following application parameters:
TA = 50°C
VIN(MAX) = 5V + 5%
VOUT1 = 1.5V
VOUT2 = 2.5V
IOUT1(MAX) = IOUT2(MAX) = 500mA
The maximum junction temperature of the LX8819 can be
calculated using the following equation:
TJ = TA + (PD(REG1) + PREG2 ) ⋅ θJA
with:
PD(REG1) = (VIN(MAX) − VOUT1 ) ⋅ IOUT1
and
PD(REG2 )
= (V
IN(MAX )
− VOUT 2 ) ⋅ IOUT 2
Substituting the known values yields a maximum junction
temperature of:
PD(REG1) = (5.25V − 1.5V ) ⋅ 0.5A = 1.75W
LAYOUT CONSIDERATION
The layout must be done with low impedance paths for
VIN, VOUT1, VOUT2 and GND by using sufficiently
wide traces to avoid voltage drops and noise pick up. The
output capacitors must be placed as close as possible to the
voltage regulator output pins.
The input capacitor should be connected between VIN
and the ground plane with short leads.
Although it may not be immediately obvious, best load
regulation for the adjustable output is obtained when the
top of the voltage feedback resistor divider (R1) is
connected as close as possible to the case of the regulator;
not to the load.
The PCB copper can be used as a heatsink for the
surface mounted package. Using the minimum size as
shown in the recommended pad layout (Figure 3), limits
the usable power to about 1W for an ambient temperature
of 50°C. Since most applications require greater than 2W
there is the need to provide additional heatsinking. This
can be accomplished by using additional copper area both
on the PCB surface, as shown in the possible heat sink
layout below, or to an embedded ground plane. Since the
die pad (copper tab) is in electrical contact with ground,
the designer can use thermal vias, on the surface of the
PCB, taking advantage of the heat-spreading (Cu) layer of
an internal ground plane.
PD(REG2) = (5.25V − 2.5V ) ⋅ 0.5A = 1.375W
TJ = 50°C + (1.75W + 1.375W ) ⋅ 30
Ground
Plane
Board Level
TJ = TA + (PD(REG1) + PD(REG2) ) ⋅ θJA
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Using the calculated total power dissipation, the
maximum junction temperature can be calculated using the
given temperature coefficients (See Thermal Data) for the
selected package.
Component
Trace
A
B
°C
W
TJ = 140°C
Figure 3 – Recommended Layout
APPLICATIONS
This value is within the safe operating range of the
device under worst case conditions
It is important to note that although each output of the
regulator will produce up to 1A in current, the individual or
total power dissipation may limit the useful total current
draw. The junction temperature should be calculated for
each individual output as well as the combined outputs to
insure that maximum junction temperature in not exceeded.
Component
Component Trace
B
VIAS
A
Ground Plane
Inner Power Plane
Backside Trace
Figure 4 – Ground Plane Heatsink
Copyright © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 6
LX8819
®
TM
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
TRANSIENT RESPONSE-CERAMIC CAP
TRANSIENT RESPONSE-TANT CAP
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VIN = 5V
VOUT1 = 1.5V 180
50mV
/ DIV
Load
50mV
/ DIV
V1 = 1.5V
50mV
/ DIV
50mV
/ DIV
V2 = 3.3V 1A Step Load
50mV
/ DIV
VOUT2 = 3.3V 1A Step Load
1A
1A
1mA
0mA
CIN = 20µF Ceramic (ESR= 45mΩ)
COUT(VOUT1) = COUT(VOUT2) = 10µF Ceramic (ESR= 75mΩ)
CIN = 22µF Tantalum (ESR= 232mΩ)
COUT(VOUT1) = COUT(VOUT2) = 10µF Tantalum (ESR= 198mΩ)
TURN ON CHARACTERISTICS
CURRENT LIMIT
500mV
/ DIV
20mV(A
C) / DIV
VOUT2 = 3.3V
500mV
/ DIV
VOUT1 = 1.5V
1.2A
VOUT2 = 3.3V
VIN = 5V
1V /
DIV
Rising Load
On V2
VOUT1 = 1.5V
500m
V/
DIV
200mA
/ DIV
RIPPLE REJECTION
45
35
30
25
CHARTS
RIPPLE REJECTION (DB)
40
20
15
10
5
0
100
1000
10000
100000
FREQUENCY (HZ)
VIN = 5V, CIN = 22µF, COUT1,2 = 10µF, VOUT2=3.3V, IOUT2=1A
Copyright © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
LX8819
®
TM
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
PACKAGE DIMENSIONS
5-Pin S-PAK
A
M
C
Dim
A
B
C
D
E
F
G
H
I
J
K
L
MILLIMETERS
MIN
MAX
9.27
9.52
7.87
8.13
1.78
2.03
2.80
3.10
1.50
1.75
0.63
0.79
1.70 BSC
0.79
1.04
6.50 BSC
0.03
0.13
10.41
10.67
0.76
1.27
INCHES
MIN
MAX
0.365
0.375
0.310
0.320
0.070
0.080
0.110
0.122
0.059
0.069
0.025
0.031
0.067 BSC
0.031
0.041
0.256 BSC
0.001
0.005
0.410
0.420
0.030
0.050
Dim
A
B
C
D
E
F
G
H
I
J
K
L
M
N
MILLIMETERS
MIN
MAX
5.96
6.22
6.47
6.73
5.00
5.22
2.18
2.38
0.45
0.55
0.63
0.78
1.27 BSC
1.08
1.29
1.01
1.11
0.76
0.86
9.70
10.08
1.52
1.62
0.03
0.13
1.27 REF
INCHES
MIN
MAX
0.234
0.244
0.254
0.264
0.196
0.205
0.085
0.093
0.017
0.021
0.024
0.030
0.050 BSC
0.042
0.050
0.039
0.043
0.029
0.033
0.381
0.396
0.059
0.063
0.001
0.005
.05 REF
L
B
K
H
J
F
G
E
I
D
DT
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DF
5-Pin TO-252 (D-PAK)
B
C
D
J
I
A
K
L
M
H
G
E
F
MECHANICALS
N
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.
Note:
Copyright © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8
LX8819
TM
®
Dual Channel 1A Low Dropout Regulator
D ATA S HEET
NOTES
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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 © 2003
Revision 1.0a, 4/29/2005
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 9