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LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
DESCRIPTION
KEY FEATURES
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The LX8816 is a dual channel positive-voltage linear regulator. This dual regulator has one fixed output coupled with an adjustable output. Each channel features low-dropout and high accuracy. The LX8816 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 and directing quiescent current to the load. The LX8816 features on-chip trimming of the internal voltage
enabling precise output voltages, typically 1% of it's specified value, while the BiPolar output transistor has a low dropout voltage even at full output current (VDO < 1.2V typ. @ 1A). Thermal and Short Circuit Current Protection are integrated on-chip and operate independently for each regulator output. The LX8816 regulator is stable with a low-value output capacitor, typically 2.2F on the outputs, allowing designers flexibility in external component selection. Microsemi's S-PAK package enables maximum power dissipation and ease of assembly using surface mount technology.
Two Independent Regulated Outputs Accurate Output Voltages Typical Dropout of 1.2V 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 4.3V to 10V Loop Stability Independent of Output Capacitor Type APPLICATIONS/BENEFITS 5V to 3.3V / ADJ Regulators Hard Disk Drives, CD-ROMs ADSL and Cable Modems Battery Charging Circuits Instrumentation PC Peripherals
IMPORTANT: For the most current data, consult MICROSEMI's website: http://www.microsemi.com
APPLICATION CIRCUITS
VIN = 5V VIN
22F
V2
10 F
LX8816-04
GND ADJ V1
3.3V @ 1.0A
R1 499 R2 499
2.5V* @ 1.0A
10F
R1 *V1 = VREF 1 + R 2 + I ADJ R1
LX8816 LX8816
TJ (C) 0 to 125
PACKAGE ORDER INFO OUTPUT V1 OUTPUT V2 (PIN 4) (PIN 5) Adj. 3.3V
DF
Plastic S-PAK 5-PIN LX8816-04CDF
Note: Available in Tape & Reel. Append the letter "T" to the part number. (i.e. LX8816-04CDFT)
Copyright 2000 Rev. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
ABSOLUTE MAXIMUM RATINGS Input Voltage (VBAT).................................................................................................. 13.5V Load Current (Internally Limited)................................................................................... 1A Power Dissipation ................................................................................... Internally Limited Short-Circuit Protection ....................................................................................... Indefinite Operating Junction Temperature ................................................................................150C Lead Temperature (Soldering 180 seconds)...............................................................235C
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.
PACKAGE PIN OUT
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Tab is GND
5 4 3 2 1
V2 V1 GND ADJ VIN
THERMAL DATA
DF PACKAGE
(Top View)
DF
Plastic S-Pak 5-Pin 4.5C/W 24.5C/W
THERMAL RESISTANCE-JUNCTION TO TAB, JT 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 PIN 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 Input. The output voltage can be set by two external resistors with the following relationship: V1 = VREF * (1 + R1 / R2) + IADJ * R1 where R1 is the resistor connected between V1 and ADJ, and R2 is the resistor connected between ADJ and GND.
ADJ GND V1
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 2.2uF. 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.
PACKAGE DATA PACKAGE DATA
V2
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.
Copyright 2000 Rev. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
RECOMMENDED OPERATING CONDITIONS Parameter
Input Voltage Output Voltage (adjustable) Load Current each output (with adequate heat sinking) Input Capacitor (VIN to GND) Output Capacitor (VOUT to GND) improve the response to these load steps.
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Symbol
VIN VOUT
Min
4.5 0 2.2 1.0
LX8816-04 Typ
Max
10 5.5 1000
Units
V V mA F F
20 10*
* 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 ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature 0C TA 125C except where otherwise noted and the following test conditions: VIN = 5V, IOUT = 10mA, C1= 10F (Tantalum), C2= C3= 4.7F (Tant.), & TJ = TA using low duty cycling methods. LX8816-04 Parameter Symbol Test Conditions Units Min Typ Max
Adjustable Output (Output 1) Reference Voltage Line Regulation Line Regulation Load Regulation Dropout Voltage Current Limit Minimum Load Current Adjust Pin Bias Current Fixed Output (Output 2) Output Voltage Line Regulation Line Regulation Load Regulation Dropout Voltage Current Limit Minimum Load Current Entire Regulator Quiescent Current Quiescent Current Ripple Rejection RMS Output Noise (% of VOUT) Thermal Shutdown IQ IQ PSRR VOUT (RMS) TJSD VIN < 10V, I1 = 5mA, I2 = 5mA VIN < 10V, I1 = 1A, I2 = 1A f=120Hz, VIN = 5V 10Hz < f < 10kHz 135 60 2.6 3.5 75 0.003 140 3.8 6 mA mA dB %V C V2 V2(VIN) V2(VIN) V2(I2) V IOUT (MAX) IL Note 1 5mA < I2 < 1A, 4.75V < VIN < 10V 4.75V < VIN < 5.5V, IOUT = 5mA 4.50V < VIN < 10V, IOUT = 5mA 5mA < I2 < 1A, VIN = 4.75V ILOAD = 1A, V2 = -2% 1.0 3.234 3.30 6 0.17 2.6 1.2 1.4 0 3.3825 8 0.22 6 1.3 V mV %V mV V A mA VREF V1(VIN) V1(VIN) VREF(I1) V IOUT (MAX) IL IADJ Note 1, The external resistor divider current can be included in this requirement. Bias current flows into part. 5mA < I1 < 1A, 4.75V < VIN < 10V 4.75V < VIN < 5.5V, IOUT = 5mA 4.50V < VIN < 10V, IOUT = 5mA 5mA < I1 < 1A, VIN = 4.75V ILOAD = 1A, V1 = -2% 1.0 1.225 1.25 1.5 0.17 0.04 1.2 1.4 2 0.12 3 1 1.273 2.5 0.22 0.15 1.3 V mV %V %V V A mA A
ELECTRICALS ELECTRICALS
Note 1: Minimum load current is defined as the amount of output current required to maintain regulation.
Copyright 2000 Rev. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
BLOCK DIAGRAM
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VIN C1 10F
1 5
VOUT2
(Fixed)
BIAS
+ -
C2 10F
1.25V VREF
VIN
4
VOUT1
(Adjustable)
R1
+ GND
3
2
C3 10F R2
Note: Application circuit above using ceramic capacitors. R1 and R2 used with adjustable version only.
R VOUT1 = 1.25 x 1 + 1 + I ADJ x R1 R2
Figure 1 - Simplified Block Diagram
BLOCK DIAGRAM BLOCK DIAGRAM
Copyright 2000 Rev. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
CHARACTERISTIC CURVES LOAD TRANSIENT RESPONSE
VIN = 20F Ceramic, ESR= 45m; V1,V2 = 10F Ceramic, ESR= 75m
50mV / DIV 50mV / DIV
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LOAD TRANSIENT RESPONSE
VIN = 22F Tantalum, ESR=232m; V1,V2 = 10F Tantalum, ESR=198m
VIN = 5V
50mV / DIV 50mV / DIV
V1 = 1.5V 180 Load
V1 = 1.5V
V2 = 3.3V 1A Step Load
50mV / DIV
V2 = 3.3V 1A Step Load
1A
1A
1mA 2s / DIV
0mA 2s / DIV
TURN ON CHARACTERISTICS
500mV / DIV
CURRENT LIMIT RESPONSE
20mV(A C) / DIV 500mV / DIV
V2 = 3.3V
V1 = 1.5V 1.2A
V2 = 3.3V
1V / DIV
VIN = 5V
500m V / DIV
V1 = 1.5V
Rising Load On V2
200mA / DIV
100s / DIV
100s / DIV
RIPPLE REJECTION VS. FREQUENCY VIN = 5V, CIN = 22F, COUT1,2 = 10F, V2=3.3V, IOUT2=1A
45 40
VOUT AND ICHIP VS. VIN RAMP
5 4.5 4 3.5
Ichip, ma
6
5
V2,(Rext=13K ohms) V1, adj(Rext=909 ohms)
RIPPLE REJECTION (DB)
35 30 25 20 15
4
VOUT (Volts)
Ichip (mA)
3 2.5 2 1.5 1 2 3
CHARTS CHARTS
10
0.5
1
5
0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
0 100 1000 10000 100000
VIN (Volts)
FREQUENCY (HZ)
Copyright 2000 Rev. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
APPLICATION INFORMATION
WWW .Microsemi .C OM
Description
The LX8816 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 combination 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.
Temperature Protection
The thermal protection shuts the LX8816 down when the junction temperature exceeds 1400C. 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 LX8816 includes over current protection, when the output load current exceeds typically 1.4A the circuit forces the regulator decrease in output.
Input Capacitor
To improve load transient response and noise rejection a input bypass capacitor is of at least 2.2uF is required. Generally we recommend a 20uF ceramic or tantalum or 22uF electrolytic capacitor.
Thermal Considerations
Thermal shutdown protects the integrated circuit from thermal overload caused from a rise in junction temperature during power dissipation. 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 dose not exceed it's maximum rating. Operating 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. Power dissipation for regulator can be calculated using the following equation:
Output Capacitor
The regulator requires output capacitors connected between V1, V2 and GND to stabilize the internal control loop. Many types of capacitors are available, with different capacitance values tolerances, temperature coefficients and equivalent series resistance. We recommend a minimum of 4.7uF. 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 0.05 to 2 ohms. We have found it best to use the same type of capacitor for both input and output bypass.
Adjustable Output Voltage
The LX8816 develops a 1.25V reference voltage between the adjust terminal and GND (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.
PD = (VIN(MAX)-V1) * I1 + (VIN(MAX)-V2 ) * I2
(Note: power dissipation resulting from quiescent (ground) current is negligible)
For the S-PAK package, thermal resistance, TAB-AMB is 25-450C/W depending on mounting technique when mounted on a FR4 copper clad PCB. Junction temperature of the integrated circuit can be calculated using:
TJUNCTION = TJUNCTION-TAB RISE _+ TTAB-AMB RISE + TAMB TTAB = PD MAX * JT
;
VIN
V2
TTAB-AMB = (PD REG1 + PD REG2) * PCB
LX8816-04
ADJ
IADJ 1A
V1
R1
An example: Given conditions: TA = 50C, VIN= 5.0V, V1= 2.5V, I1= 210mA, V2= 3.3V I2= 1A. Calculated values:
TJ-TAB REG1
= (5V-2.5V) * (210mA) * 4.5C/W = (0.525) * 4.5C/W = 2.4C
VREF
APPLICATION APPLICATION
R1 V1 = VREF 1 + R 2 + I ADJ R1
TJ-TAB REG2
R2
= (5V-3.3V) * (1.0A) * 4.5C/W = (1.7) * 4.5C/W = 7.7C
FIGURE 2 - BASIC ADJUSTABLE REGULATOR
TTAB-AMB RISE = ( 0.525W + 1.7W ) * 30C/W = 66.8C TJUNCTION = 10.1C + 66.8C + 50C = 126.9C
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 the maximum junction temperature in not exceeded.
Page 6
Minimum Load Requirement
The LX8816 has a minimum load is requirement for proper output regulation. This minimum current is specified at 0mA for the fixed output and 2ma for the adjustable output regulators.
Copyright 2000 Rev. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
APPLICATION INFORMATION
WWW .Microsemi .C OM
Layout Consideration
The layout must be done with low impedance paths for VIN, V1, V2 and Ground 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. To allow the same voltage reference for all circuits, use a star configuration from the output capacitors to the different loads. The input capacitor should be connected between VIN and ground with short leads. Although it may not be immediately obvious, best load regulation for the adjustable output is obtained when the top of the resistor divider, (R1), is connected as close as possible to the case of the regulator, not to the load.
Heatsink Consideration
The PCB copper can be used as a heatsink for the surface mounted S-Pak. Using the minimum size as shown in the recommended pad layout limits the usable power to about 1W for ambient temperature of 50C. Since most applications require greater than 2W there is the need to provide additional heat sinking. 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.
HEAT SINK LAYOUT
B o a rd L e ve l
Com ponent T ra ce
G ro u n d P la n e
B A
Component
B
VIAS
Component Trace Ground Plane Inner Power Plane Backside Trace
A
Figure 3 - Heatsink RECOMMENDED MINIMUM PCB FOOTPRINT
9.75mm
11.56mm 9.98mm
APPLICATION APPLICATION
8.84mm 7.92mm 8.89mm 1.37mm 0mm .86mm 4.39mm 5.36mm 1.83mm 3.28mm
Copyright 2000 Rev. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
PACKAGE DIMENSIONS
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DF
5-Pin Plastic 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 M
Note:
MILLIMETERS MIN MAX 9.27 9.52 7.87 8.13 1.78 2.03 8.03 BSC 0.25 BSC 0.63 0.79 1.70 BSC 0.79 1.04 6.50 BSC 0.03 0.13 10.41 10.67 0.25 BSC 0.76 1.27
INCHES MIN MAX 0.365 0.375 0.310 0.320 0.070 0.080 0.316 BSC 0.010 BSC 0.025 0.031 0.067 BSC 0.031 0.041 0.256 BSC 0.001 0.005 0.410 0.420 0.01 BSC 0.03 0.05
MECHANICALS MECHANICALS
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. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8
LX8816
INTEGRATED PRODUCTS
Dual Channel 1A Low Dropout Regulator
PRODUCTION DATA SHEET
NOTES
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N 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. 1.2a, 2002-11-01
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 9
Digitally signed by KD DN: cn=KD, o=Microse mi, c=US Date: 2002.11.01 10:07:28 -08'00'
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