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LX8819
TM (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
DESCRIPTION
KEY FEATURES Two Independent Regulated Outputs Accurate Output Voltages Typical Dropout of 1.25V at 1A and 1.1V at 500mA Independent Thermal and Current Limit Protection Low Profile 5 Lead SMT Power Package Low Tolerance Load Regulation Wide DC Supply Voltage of 3.5V to 10V Loop Stability Independent of Output Capacitor Type
APPLICATIONS
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
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 2.2F 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.
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PRODUCT HIGHLIGHT
V IN = 5V
22 F
VIN
VOUT2 10 F
VOUT2 = 3.3V/2.5V @ 1A VOUT1 = 1.8V @ 1A
8819
GND VOUT1 ADJ 221 10 F
499
PACKAGE ORDER INFO
LX8819 LX8819
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
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 (c) 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 (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
ABSOLUTE MAXIMUM RATINGS
PACKAGE PIN OUT
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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 ......................................................... 0C to 150C Maximum Operating Junction Temperature ................................................ 150C Storage Temperature Range...........................................................-65C to 150C Lead Temperature (Soldering 180 seconds) ................................................ 235C RoHS Peak Package Solder Reflow Temperature (40 second maximum exposure) ..................................................... 260C (+0, -5)
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.
DF PACKAGE
(Top View)
RoHS 100% Matte Tin Lead Finish
TAB is GND VOUT2
THERMAL DATA
DF
Plastic S-PAK 5-Pin 5C/W 30C/W
DT PACKAGE
(Top View)
VOUT1 GND ADJ VIN
THERMAL RESISTANCE-JUNCTION TO CASE, JC THERMAL RESISTANCE-JUNCTION TO AMBIENT, JA
DT
Plastic D-PAK 5-Pin 6C/W 32C/W
THERMAL RESISTANCE-JUNCTION TO CASE, JC THERMAL RESISTANCE-JUNCTION TO AMBIENT, JA
Junction Temperature Calculation: TJ = TA + (PD x JA). The JA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. JA can vary from 25C/W to > 40C/W depending on mounting technique. (See Application Notes Section: Thermal considerations)
FUNCTIONAL PIN DESCRIPTION Name VIN Description Positive unregulated supply input for the regulator - Bypass to GND with at least 2.2F 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: ADJ
VOUT1 = VREF 1 +

+ I ADJ R1 R2
R1
where R1 is the resistor connected between VOUT1 and ADJ, and R2 is the resistor connected between ADJ and GND. GND VOUT1
PACKAGE DATA PACKAGE DATA
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.
Adjustable regulator output (Regulator #1) - It is recommended to bypass to GND with at least 2.2F. 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. Fixed regulator output (Regulator #2) - It is recommended to bypass to GND with at least 2.2F. 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.
VOUT2
Copyright (c) 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
LX8819
TM (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
RECOMMENDED OPERATING CONDITIONS
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Parameter 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
Symbol VIN VOUT IOUT CIN COUT
Min 4.5 3.5 0 2.2 1.0
LX8819 Typ
Max 10 10 5 1000
Units V V V mA F F
20 10
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.
ELECTRICAL CHARACTERISTICS Unless otherwise specified, the following specifications apply over the operating ambient temperature 0C TA 125C except where otherwise noted and with the following test conditions: VIN = 5V, IOUT = 10mA, CIN= 10F (Tantalum), COUT = 4.7F (Tant.), and TJ = TA using low duty cycling methods. Parameter
ADJUSTABLE OUTPUT (VOUT1)
Symbol VREF VREF(VIN) VREF(IOUT) V IOUT (MAX) IL IADJ
Test Conditions 5mA < IOUT1 < 1A, 4.75V < VIN < 5.5V 3.75V < VIN < 5.5V, IOUT1 = 5mA 5mA < IOUT1 < 1A, VIN = 4.75V IOUT1 = 1A, V1 = -1%
Min 1.225
LX8819 Typ 1.25 1.5 0.18 1.3 1.4 2 -0.12 3.30 2.5 6 6 1.25 1.4
Max
Units
Reference Voltage Line Regulation Load Regulation Dropout Voltage Current Limit Minimum Load Current Adjust Pin Bias Current
FIXED OUTPUT (OUTPUT 2)
1.0 Note 3
1.275 V 6 mV 0.36 %VOUT 1.46 V A 3 mA -1 A 3.383 2.562 8 12 1.41 1.25 0
Output Voltage - LX8819-33 Output Voltage - LX8819-25 Line Regulation Load Regulation Dropout Voltage Current Limit Minimum Load Current
ENTIRE REGULATOR
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 VIN < 5.5V, IOUT1 = 5mA, IOUT2 = 5mA VIN < 5.5V, IOUT1 = 1A, IOUT2 = 1A -3.3 Voltage Rising -2.5 Voltage Rising @ 25 C
3.217 2.437
V mV mV V V A mA
1.0
Quiescent Current VIN Under Voltage Lockout Threshold VOUT Rise Time for VIN Switched On Ripple Rejection RMS Output Noise Thermal Shutdown
Note
IQ UVLO VOUT(tR) PSRR VOUT (RMS) TJSD
2.6 3.5 2.5 2.5 80
4.2 5 4.5 3.6 300
PACKAGE DATA PACKAGE DATA
mA V s dB %VOUT C
f=120Hz, VIN = 5V 10Hz < f < 10kHz
60 150
75 0.003 165
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 (c) 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
LX8819
TM (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
SIMPLIFIED BLOCK DIAGRAM
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VIN C1 10 F
1 5
BIAS
OUT2 (Fi x e d )
V
+ -
C2 10 F
1.25V VREF
VIN
4
OUT1 (Ad j u s ta b l e )
V
R1
+ GND
3
2
C3 10 F 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 . 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 . i
R VOUT1 = VREF 1 + 1 + IADJ R1 R 2
Figure 1 - Simplified Block Diagram
ELECTRICALS ELECTRICALS
Copyright (c) 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 (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
APPLICATION INFORMATION
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. INPUT CAPACITOR To improve load transient response and noise rejection an input bypass capacitor of at least 2.2F is required. Generally it is recommended that a 20F ceramic/tantalum or 22F 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 4.7F 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 50m to 2. It is generally best to use the same type of capacitors for both input and output bypassing. 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. 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.
VIN
VOUT2
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LX8819
ADJ
IADJ 1A
VOUT1
R1
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 140C. 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 150C 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:
A APPLICATIONS
PD = (VIN(MAX) - VOUT1 ) IOUT1 + (VIN(MAX) - VOUT2 ) IOUT2
(Note: Power dissipation resulting from quiescent (ground) current is negligible and ignored)
Copyright (c) 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 5
LX8819
TM (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
APPLICATION INFORMATION
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. THERMAL CALCULATION EXAMPLE Given the following application parameters:
TA = 50C VIN(MAX) = 5V + 5% VOUT1 = 1.5V VOUT2 = 2.5V IOUT1(MAX) = IOUT2(MAX) = 500mA
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The maximum junction temperature of the LX8819 can be calculated using the following equation:
TJ = TA + (PD(REG1) + PREG2 ) JA
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 PD(REG2) = (5.25V - 2.5V ) 0.5A = 1.375W TJ = TA + (PD(REG1) + PD(REG2) ) JA TJ = 50C + (1.75W + 1.375W ) 30 TJ = 140C C W
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 50C. 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.
Board Level
Component Trace B
Ground Plane
A
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.
Figure 3 - Recommended Layout
Component
B
VIAS
APPLICATIONS APPLICATIONS
Component Trace Ground Plane Inner Power Plane Backside Trace
A
Figure 4 - Ground Plane Heatsink
Copyright (c) 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 (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
TRANSIENT RESPONSE-CERAMIC CAP
VOUT1 = 1.5V 180 Load
TRANSIENT RESPONSE-TANT CAP
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VIN = 5V
50mV / DIV 50mV / DIV
50mV / DIV 50mV / DIV
V1 = 1.5V
50mV / DIV
V2 = 3.3V 1A Step Load
VOUT2 = 3.3V 1A Step Load
1A
1A
1mA
0mA
CIN = 20F Ceramic (ESR= 45m) COUT(VOUT1) = COUT(VOUT2) = 10F Ceramic (ESR= 75m)
CIN = 22F Tantalum (ESR= 232m) COUT(VOUT1) = COUT(VOUT2) = 10F Tantalum (ESR= 198m)
TURN ON CHARACTERISTICS
500mV / DIV
CURRENT LIMIT
20mV(A C) / DIV 500mV / DIV
VOUT2 = 3.3V
VOUT1 = 1.5V VOUT2 = 3.3V 1.2A
1V / DIV
VIN = 5V
500m V/ DIV
VOUT1 = 1.5V
Rising Load On V2
200mA / DIV
RIPPLE REJECTION
45 40
RIPPLE REJECTION (DB)
35 30 25
CHARTS CHARTS
20 15 10 5 0 100 1000 10000 100000
FREQUENCY (HZ) VIN = 5V, CIN = 22F, COUT1,2 = 10F, VOUT2=3.3V, IOUT2=1A
Copyright (c) 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 (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
PACKAGE DIMENSIONS
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DF
5-Pin S-PAK
M A C
L
B
K
H J F G I E
D
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
DT
5-Pin TO-252 (D-PAK)
B C J
D I
A K L M H G F E
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
MECHANICALS MECHANICALS
N
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 (c) 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 (R)
Dual Channel 1A Low Dropout Regulator
DATA SHEET
NOTES
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NOTES 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 (c) 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

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