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LT3014 20mA, 3V to 80V Low Dropout Micropower Linear Regulator
FEATURES

DESCRIPTIO
Wide Input Voltage Range: 3V to 80V Low Quiescent Current: 7A Low Dropout Voltage: 350mV Output Current: 20mA LT3014HV Survives 100V Transients (2ms) No Protection Diodes Needed Adjustable Output from 1.22V to 60V 1A Quiescent Current in Shutdown Stable with 0.47F Output Capacitor Stable with Aluminum, Tantalum or Ceramic Capacitors Reverse-Battery Protection No Reverse Current Flow from Output Thermal Limiting Available in 5-Lead ThinSOTTM and 8-Lead DFN Packages
The LT(R)3014 is a high voltage, micropower low dropout linear regulator. The device is capable of supplying 20mA of output current with a dropout voltage of 350mV. Designed for use in battery-powered or high voltage systems, the low quiescent current (7A operating and 1A in shutdown) makes the LT3014 an ideal choice. Quiescent current is also well controlled in dropout. Other features of the LT3014 include the ability to operate with very small output capacitors. The regulators are stable with only 0.47F on the output while most older devices require between 10F and 100F for stability. Small ceramic capacitors can be used without the necessary addition of ESR as is common with other regulators. Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting and reverse current protection. The device is available as an adjustable device with a 1.22V reference voltage. The LT3014 regulator is available in the 5-lead ThinSOT and 8-lead DFN packages.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6118263, 6144250.
APPLICATIO S

Low Current High Voltage Regulators Regulator for Battery-Powered Systems Telecom Applications Automotive Applications
TYPICAL APPLICATIO
400
5V Supply with Shutdown
IN VIN 5.4V TO 80V 1F SHDN GND ADJ 1.27M
3014 TA01
350
OUT LT3014 3.92M
VOUT 5V 20mA 0.47F
DROPOUT VOLTAGE (mV)
300 250 200 150 100 50 0 0 2 4 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA)
3014 TA02
VSHDN OUTPUT <0.3V OFF >2.0V ON NC ON
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Dropout Voltage
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LT3014
ABSOLUTE
(Note 1)
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RATI GS
Storage Temperature Range ThinSOT Package......................... -65C to 150C DFN Package ............................... -65C to 125C Operating Junction Temperature Range (Notes 3, 10, 11) ......................... -40C to 125C Lead Temperature, SOT-23 (Soldering, 10 sec) ..................................... 300C
IN Pin Voltage, Operating ................................. 80V Transient (2ms Survival, LT3014HV) .............. +100V OUT Pin Voltage ............................................... 60V IN to OUT Differential Voltage ........................... 80V ADJ Pin Voltage .................................................. 7V SHDN Pin Input Voltage ......................... +80V, -40V Output Short-Circuit Duration ..................... Indefinite
PACKAGE/ORDER I FOR ATIO
TOP VIEW IN 1 GND 2 SHDN 3 4 ADJ 5 OUT
ORDER PART NUMBER
OUT 1 2 3 4
LT3014ES5 LT3014HVES5 S5 PART MARKING LTBMF LTBRS
S5 PACKAGE 5-LEAD PLASTIC SOT-23 TJMAX = 125C, JA = 150C/ W JC = 25C/ W MEASURED AT PIN 2. SEE APPLICATIONS INFORMATION SECTION.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25C.
PARAMETER Minimum Input Voltage ADJ Pin Voltage (Notes 2, 3) Line Regulation Load Regulation Dropout Voltage VIN = VOUT(NOMINAL) (Notes 4, 5) CONDITIONS ILOAD = 20mA VIN = 3.3V, ILOAD = 100A 3.3V < VIN < 80V, 100A < ILOAD < 20mA VIN = 3.3V to 80V, ILOAD = 100A (Note 2) VIN = 3.3V, ILOAD = 100A to 20mA (Note 2) VIN = 3.3V, ILOAD = 100A to 20mA ILOAD = 100A ILOAD = 100A ILOAD = 1mA ILOAD = 1mA ILOAD = 10mA ILOAD = 10mA ILOAD = 20mA ILOAD = 20mA GND Pin Current VIN = VOUT(NOMINAL) (Notes 4, 6) ILOAD = 0mA ILOAD = 100A ILOAD = 1mA ILOAD = 10mA ILOAD = 20mA
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TOP VIEW 8 9 7 6 5 IN NC NC SHDN
ORDER PART NUMBER LT3014EDD LT3014HVEDD DD PART MARKING
ADJ NC GND
DD PACKAGE 8-LEAD (3mm x 3mm) PLASTIC DFN EXPOSED PAD IS GND (PIN 9) MUST BE SOLDERED TO PCB TJMAX = 125C, JA = 40C/ W JC = 10C/ W MEASURED AT PIN 9.
LBMG LBRT
MIN 1.200 1.180

TYP 3 1.220 1.220 1 13 120
MAX 3.3 1.240 1.260 10 25 40 180 250 270 360 350 450 410 570 20 30 100 450 1000
UNITS V V V mV mV mV mV mV mV mV mV mV mV mV A A A A A
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200
300
350

7 12 40 250 650
LT3014
ELECTRICAL CHARACTERISTICS
The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25C.
PARAMETER Output Voltage Noise ADJ Pin Bias Current Shutdown Threshold SHDN Pin Current (Note 8) Quiescent Current in Shutdown Ripple Rejection Current Limit Input Reverse Leakage Current Reverse Output Current (Note 9) CONDITIONS COUT = 0.47F, ILOAD = 20mA, BW = 10Hz to 100kHz (Note 7) VOUT = Off to On VOUT = On to Off VSHDN = 0V VSHDN = 6V VIN = 6V, VSHDN = 0V VIN = 7V(Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 20mA VIN = 7V, VOUT = 0V VIN = 3.3V, VOUT = -0.1V (Note 2) VIN = -80V, VOUT = 0V VOUT = 1.22V, VIN < 1.22V (Note 2)

MIN
TYP 115 4
MAX 10 2 4 1 4
UNITS VRMS nA V V A A A dB mA mA
0.25
1.3 1.3 1 0 1
60 25
70 70 6 2 4
mA A
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT3014 is tested and specified for these conditions with the ADJ pin connected to the OUT pin. Note 3: Operating conditions are limited by maximum junction temperature. The regulated output voltage specification will not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range must be limited. When operating at maximum output current, the input voltage range must be limited. Note 4: To satisfy requirements for minimum input voltage, the LT3014 is tested and specified for these conditions with an external resistor divider (249k bottom, 392k top) for an output voltage of 3.3V. The external resistor divider adds a 5A DC load on the output. Note 5: Dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. In dropout, the output voltage is equal to (VIN - VDROPOUT).
Note 6: GND pin current is tested with VIN = VOUT (nominal) and a current source load. This means the device is tested while operating in its dropout region. This is the worst-case GND pin current. The GND pin current decreases slightly at higher input voltages. Note 7: ADJ pin bias current flows into the ADJ pin. Note 8: SHDN pin current flows out of the SHDN pin. Note 9: Reverse output current is tested with the IN pin grounded and the OUT pin forced to the rated output voltage. This current flows into the OUT pin and out of the GND pin. Note 10: The LT3014E is guaranteed to meet performance specifications from 0C to 125C operating junction temperature. Specifications over the -40C to 125C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. Note 11: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability.
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LT3014 TYPICAL PERFOR A CE CHARACTERISTICS
Typical Dropout Voltage
500 450
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
400 350 300 250 200 150 100 50 0
TJ = 125C
TJ = 25C
0
2
4
6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA)
3014 G01
Quiescent Current
16 14
QUIESCENT CURRENT (A)
ADJ PIN VOLTAGE (V)
12 10 8 6 4 2 0 - 50 - 25 0 VSHDN = 0V 50 75 25 TEMPERATURE (C) 100 125 VSHDN = VIN
1.230 1.225 1.220 1.215 1.210 1.205 1.200 - 50 - 25 0 50 75 25 TEMPERATURE (C) 100 125
QUIESCENT CURRENT (A)
VIN = 6V RL = IL = 0
GND Pin Current
1000 TJ = 25C 900 *FOR VOUT = 1.22V 800
GND PIN CURRENT (A)
1000
700 600 500 400 300 200 100 0 0 1 2
RL = 61 IL = 20mA*
SHDN PIN THRESHOLD (V)
GND PIN CURRENT (A)
RL = 122 IL = 10mA* RL = 1.22k IL = 1mA* 34567 INPUT VOLTAGE (V) 8 9 10
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3014 G04 3014 G07
Guaranteed Dropout Voltage
600 500 400 TJ 25C 300 200 100 0 0 2 4 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA)
3014 G02
Dropout Voltage
500 450
= TEST POINTS TJ 125C
400 350 300 250 200 150 100 50 0 -50 -25 50 25 0 75 TEMPERATURE (C) 100 125 IL = 100A IL = 1mA IL = 20mA IL = 10mA
3014 G03
ADJ Pin Voltage
1.240 1.235 IL = 100A 16
Quiescent Current
TJ = 25C 14 RL = VOUT = 1.22V 12 10 8 6 4 2 0 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 VSHDN = 0V VSHDN = VIN
3014 G05
3014 G06
GND Pin Current vs ILOAD
VIN = 3.3V 900 TJ = 25C = 1.22V V 800 OUT 700 600 500 400 300 200 100 0 0 2 4 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA)
3014 G08
SHDN Pin Threshold
2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125
3014 G09
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LT3014 TYPICAL PERFOR A CE CHARACTERISTICS
SHDN Pin Current
1.2 TJ = 25C CURRENT FLOWS 1.0 OUT OF SHDN PIN
1.2 1.0 0.8 0.6 0.4 0.2
ADJ PIN BIAS CURRENT (nA)
SHDN PIN CURRENT (A)
SHDN PIN CURRENT (A)
0.8 0.6 0.4 0.2 0 0 0.5
2.5 3 1 1.5 2 SHDN PIN VOLTAGE (V)
Current Limit
80
100 90 80
REVERSE OUTPUT CURRENT (A)
VOUT = 0V 70 TJ = 25C
CURRENT LIMIT (mA)
CURRENT LIMIT (mA)
60 50 40 30 20 10 0 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V)
3014 G13
Reverse Output Current
8 7 6 5 4 3 2 1 0 - 50 - 25 0 50 75 25 TEMPERATURE (C) 100 125 VIN = 0V VOUT = VADJ = 1.22V
REVERSE OUTPUT CURRENT (A)
RIPPLE REJECTION (dB)
66 64 62 60 58 56 - 50 - 25 0 50 75 25 TEMPERATURE (C) 100 125
RIPPLE REJECTION (dB)
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3.5 4
3014 G10
SHDN Pin Current
1.6 VSHDN = 0V 1.4 CURRENT FLOWS OUT OF SHDN PIN 14 12 10 8 6 4 2
ADJ Pin Bias Current
0 - 50 - 25
0
50 75 25 TEMPERATURE (C)
100
125
0 - 50 - 25
0
50 75 25 TEMPERATURE (C)
100
125
3014 G11
3014 G12
Current Limit
VIN = 7V VOUT = 0V
Reverse Output Current
50 TJ = 25C 45 VIN = 0V = VADJ V 40 OUT 35 30 25 20 15 10 5 0 CURRENT FLOWS INTO OUTPUT PIN ADJ PIN ESD CLAMP
70 60 50 40 30 20 10 0 -50 -25 50 25 0 75 TEMPERATURE (C) 100 125
0
1
2
345678 OUTPUT VOLTAGE (V)
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10
3014 G14
3014 G15
Input Ripple Rejection
72 VIN = 7V + 0.5VP-P 70 RIPPLE AT f = 120Hz IL = 20mA 68
80 70 60 50 40 30 20 10
Input Ripple Rejection
VIN = 7V + 50mVRMS RIPPLE IL = 20mA
COUT = 4.7F
COUT = 0.47F 100 1k 10k FREQUENCY (Hz) 100k 1M
3014 G18
0 10
3014 G16
3014 G17
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LT3014 TYPICAL PERFOR A CE CHARACTERISTICS
Minimum Input Voltage
3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 -50 -25 ILOAD = 20mA 0 -5
IL = 100A TO 20mA VOUT = 1.22V
OUTPUT NOISE SPECTRAL DENSITY (V/Hz)
MINIMUM INPUT VOLTAGE (V)
LOAD REGULATION (mV)
25 75 0 50 TEMPERATURE (C)
10Hz to 100kHz Output Noise
OUTPUT VOLTAGE DEVIATION (V)
VOUT 200V/DIV
LOAD CURRENT (mA)
COUT = 0.47F IL = 20mA VOUT = 1.22V
PI FU CTIO S
(SOT-23 Package/DD Package)
IN (Pin 1/Pin 8): Input. Power is supplied to the device through the IN pin. A bypass capacitor is required on this pin if the device is more than six inches away from the main input filter capacitor. In general, the output impedance of a battery rises with frequency, so it is advisable to include a bypass capacitor in battery-powered circuits. A bypass capacitor in the range of 0.1F to 10F is sufficient. The LT3014 is designed to withstand reverse voltages on the IN pin with respect to ground and the OUT pin. In the case of a reversed input, which can happen if a battery is plugged in backwards, the LT3014 will act as if there is a diode in series with its input. There will be no reverse current flow into the LT3014 and no reverse voltage will
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100
3014 G19
Load Regulation
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Output Noise Spectral Density
COUT = 0.47F IL = 20mA VOUT = 1.22V
-10 -15 -20 -25 -30 -35
1
0.1
125
-40 - 50 - 25
0
25
50
75
100
125
0.01 10 100 1k 10k FREQUENCY (Hz) 100k
3014 G21
TEMPERATURE (C)
3014 G20
Transient Response
0.04 0.02 0 -0.02 -0.04 VIN = 7V VOUT = 5V CIN = COUT = 0.47F CERAMIC ILOAD = 1mA TO 5mA
6 4 2 0 0 200 600 400 TIME (s) 800 1000
3014 G23
1ms/DIV
3014 G22
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appear at the load. The device will protect both itself and the load. GND (Pin 2/Pins 4, 9): Ground. SHDN (Pin 3/Pin 5): Shutdown. The SHDN pin is used to put the LT3014 into a low power shutdown state. The output will be off when the SHDN pin is pulled low. The SHDN pin can be driven either by 5V logic or opencollector logic with a pull-up resistor. The pull-up resistor is only required to supply the pull-up current of the opencollector gate, normally several microamperes. If unused, the SHDN pin can be left open circuit. The device will be active, output on, if the SHDN pin is not connected.
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LT3014
PI FU CTIO S
ADJ (Pin 4/Pin 2): Adjust. This is the input to the error amplifier. This pin is internally clamped to 7V. It has a bias current of 4nA which flows into the pin (see curve of ADJ Pin Bias Current vs Temperature in the Typical Performance Characteristics). The ADJ pin voltage is 1.22V referenced to ground, and the output voltage range is 1.22V to 60V.
APPLICATIO S I FOR ATIO
The LT3014 is a 20mA high voltage low dropout regulator with micropower quiescent current and shutdown. The device is capable of supplying 20mA at a dropout voltage of 350mV. The low operating quiescent current (7A) drops to 1A in shutdown. In addition to the low quiescent current, the LT3014 incorporates several protection features which make it ideal for use in battery-powered systems. The device is protected against both reverse input and reverse output voltages. In battery backup applications where the output can be held up by a backup battery when the input is pulled to ground, the LT3014 acts like it has a diode in series with its output and prevents reverse current flow. Adjustable Operation The LT3014 has an output voltage range of 1.22V to 60V. The output voltage is set by the ratio of two external resistors as shown in Figure 2. The device servos the output to maintain the voltage at the adjust pin at 1.22V referenced to ground. The current in R1 is then equal to 1.22V/R1 and the current in R2 is the current in R1 plus the ADJ pin bias current. The ADJ pin bias current, 4nA at 25C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure 1. The value of R1 should be less than 1.62M to minimize errors in the output voltage caused by the ADJ pin bias current. Note that in shutdown the output is turned off and the divider current will be zero. The device is tested and specified with the ADJ pin tied to the OUT pin and a 5A DC load (unless otherwise specified) for an output voltage of 1.22V. Specifications for output voltages greater
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(SOT-23 Package/DD Package)
OUT (Pin 5/Pin 1): Output. The output supplies power to the load. A minimum output capacitor of 0.47F is required to prevent oscillations. Larger output capacitors will be required for applications with large transient loads to limit peak voltage transients. See the Applications Information section for more information on output capacitance and reverse output characteristics.
than 1.22V will be proportional to the ratio of the desired output voltage to 1.22V (VOUT/1.22V). For example, load regulation for an output current change of 1mA to 20mA is -13mV typical at VOUT = 1.22V. At VOUT = 12V, load regulation is: (12V/1.22V) * (-13mV) = -128mV
IN VIN OUT LT3014 ADJ GND R1
3014 F01
R2
+
VOUT
VOUT = 1.22V * 1 + R2 + (IADJ)(R2) R1 VADJ = 1.22V IADJ = 4nA AT 25C OUTPUT RANGE = 1.22V TO 60V
()
Figure 1. Adjustable Operation
Output Capacitance and Transient Response The LT3014 is designed to be stable with a wide range of output capacitors. The ESR of the output capacitor affects stability, most notably with small capacitors. A minimum output capacitor of 0.47F with an ESR of 3 or less is recommended to prevent oscillations. The LT3014 is a micropower device and output transient response will be a function of output capacitance. Larger values of output capacitance decrease the peak deviations and provide improved transient response for larger load current changes. Bypass capacitors, used to decouple individual components powered by the LT3014, will increase the effective output capacitor value.
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LT3014
APPLICATIO S I FOR ATIO
Extra consideration must be given to the use of ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior across temperature and applied voltage. The most common dielectrics used are Z5U, Y5V, X5R and X7R. The Z5U and Y5V dielectrics are good for providing high capacitances in a small package, but exhibit strong voltage and temperature coefficients as shown in Figures 2 and 3. When used with a 5V regulator, a 10F Y5V capacitor can exhibit an effective value as low as 1F to 2F over the operating temperature range. The X5R and X7R dielectrics result in more stable characteristics and are more suitable for use as the output capacitor. The X7R type has better stability across temperature, while the X5R is less expensive and is available in higher values. Voltage and temperature coefficients are not the only sources of problems. Some ceramic capacitors have a piezoelectric response. A piezoelectric device generates voltage across its terminals due to mechanical stress,
20 0
CHANGE IN VALUE (%)
BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F
CHANGE IN VALUE (%)
X5R -20 -40 -60 Y5V -80
-100
0
2
4
8 6 10 12 DC BIAS VOLTAGE (V)
14
16
3014 F02
Figure 2. Ceramic Capacitor DC Bias Characteristics
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similar to the way a piezoelectric accelerometer or microphone works. For a ceramic capacitor the stress can be induced by vibrations in the system or thermal transients. Thermal Considerations The power handling capability of the device will be limited by the maximum rated junction temperature (125C). The power dissipated by the device will be made up of two components: 1. Output current multiplied by the input/output voltage differential: IOUT * (VIN - VOUT) and, 2. GND pin current multiplied by the input voltage: IGND * VIN. The GND pin current can be found by examining the GND Pin Current curves in the Typical Performance Characteristics. Power dissipation will be equal to the sum of the two components listed above.
40 20 0 X5R -20 -40 -60 -80 Y5V BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F -100 50 25 75 -50 -25 0 TEMPERATURE (C) 100 125
3014 F03
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Figure 3. Ceramic Capacitor Temperature Characteristics
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LT3014
APPLICATIO S I FOR ATIO
The LT3014 regulator has internal thermal limiting designed to protect the device during overload conditions. For continuous normal conditions the maximum junction temperature rating of 125C must not be exceeded. It is important to give careful consideration to all sources of thermal resistance from junction to ambient. Additional heat sources mounted nearby must also be considered. For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices. The following table lists thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 board with one ounce copper.
Table 1. SOT-23 Measured Thermal Resistance
COPPER AREA TOPSIDE 2500 sq mm 1000 sq mm 225 sq mm 100 sq mm 50 sq mm BACKSIDE 2500 sq mm 2500 sq mm 2500 sq mm 2500 sq mm 2500 sq mm BOARD AREA 2500 sq mm 2500 sq mm 2500 sq mm 2500 sq mm 2500 sq mm THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 125C/W 125C/W 130C/W 135C/W 150C/W
Table 2. DFN Measured Thermal Resistance
COPPER AREA TOPSIDE 2500 sq mm 1000 sq mm 225 sq mm 100 sq mm BACKSIDE 2500 sq mm 2500 sq mm 2500 sq mm 2500 sq mm BOARD AREA 2500 sq mm 2500 sq mm 2500 sq mm 2500 sq mm THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 40C/W 45C/W 50C/W 62C/W
For the DFN package, the thermal resistance junction-tocase (JC), measured at the exposed pad on the back of the die, is 16C/W.
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Continuous operation at large input/output voltage differentials and maximum load current is not practical due to thermal limitations. Transient operation at high input/ output differentials is possible. The approximate thermal time constant for a 2500sq mm 3/32" FR-4 board with maximum topside and backside area for one ounce copper is 3 seconds. This time constant will increase as more thermal mass is added (i.e. vias, larger board, and other components). For an application with transient high power peaks, average power dissipation can be used for junction temperature calculations as long as the pulse period is significantly less than the thermal time constant of the device and board. Calculating Junction Temperature Example 1: Given an output voltage of 5V, an input voltage range of 24V to 30V, an output current range of 0mA to 20mA, and a maximum ambient temperature of 50C, what will the maximum junction temperature be? The power dissipated by the device will be equal to: IOUT(MAX) * (VIN(MAX) - VOUT) + (IGND * VIN(MAX)) where: IOUT(MAX) = 20mA VIN(MAX) = 30V IGND at (IOUT = 20mA, VIN = 30V) = 0.55mA So: P = 20mA * (30V - 5V) + (0.55mA * 30V) = 0.52W The thermal resistance for the DFN package will be in the range of 40C/W to 62C/W depending on the copper area. So the junction temperature rise above ambient will be approximately equal to: 0.52W * 50C/W = 26C
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LT3014
APPLICATIO S I FOR ATIO
The maximum junction temperature will then be equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature or: TJMAX = 50C + 26C = 76C Example 2: Given an output voltage of 5V, an input voltage of 48V that rises to 72V for 5ms(max) out of every 100ms, and a 5mA load that steps to 20mA for 50ms out of every 250ms, what is the junction temperature rise above ambient? Using a 500ms period (well under the time constant of the board), power dissipation is as follows: P1(48V in, 5mA load) = 5mA * (48V - 5V) + (100A * 48V) = 0.22W P2(48V in, 20mA load) = 20mA * (48V - 5V) + (0.55mA * 48V) = 0.89W P3(72V in, 5mA load) = 5mA * (72V - 5V) + (100A * 72V) = 0.34W P4(72V in, 20mA load) = 20mA * (72V - 5V) + (0.55mA * 72V) = 1.38W Operation at the different power levels is as follows: 76% operation at P1, 19% for P2, 4% for P3, and 1% for P4. PEFF = 76%(0.22W) + 19%(0.89W) + 4%(0.34W) + 1%(1.38W) = 0.36W With a thermal resistance in the range of 40C/W to 62C/W, this translates to a junction temperature rise above ambient of 20C.
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Protection Features The LT3014 incorporates several protection features which make it ideal for use in battery-powered circuits. In addition to the normal protection features associated with monolithic regulators, such as current limiting and thermal limiting, the device is protected against reverse-input voltages, and reverse voltages from output to input. Current limit protection and thermal overload protection are intended to protect the device against current overload conditions at the output of the device. For normal operation, the junction temperature should not exceed 125C. The input of the device will withstand reverse voltages of 80V. Current flow into the device will be limited to less than 6mA (typically less than 100A) and no negative voltage will appear at the output. The device will protect both itself and the load. This provides protection against batteries which can be plugged in backward. The ADJ pin can be pulled above or below ground by as much as 7V without damaging the device. If the input is left open circuit or grounded, the ADJ pin will act like an open circuit when pulled below ground, and like a large resistor (typically 100k) in series with a diode when pulled above ground. If the input is powered by a voltage source, pulling the ADJ pin below the reference voltage will cause the device to current limit. This will cause the output to go to an unregulated high voltage. Pulling the ADJ pin above the reference voltage will turn off all output current.
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LT3014
APPLICATIO S I FOR ATIO
In situations where the ADJ pin is connected to a resistor divider that would pull the ADJ pin above its 7V clamp voltage if the output is pulled high, the ADJ pin input current must be limited to less than 5mA. For example, a resistor divider is used to provide a regulated 1.5V output from the 1.22V reference when the output is forced to 60V. The top resistor of the resistor divider must be chosen to limit the current into the ADJ pin to less than 5mA when the ADJ pin is at 7V. The 53V difference between the OUT and ADJ pins divided by the 5mA maximum current into the ADJ pin yields a minimum top resistor value of 10.6k. In circuits where a backup battery is required, several different input/output conditions can occur. The output voltage may be held up while the input is either pulled to ground, pulled to some intermediate voltage, or is left
50 TJ = 25C 45 VIN = 0V = VADJ V 40 OUT 35 30 25 20 15 10 5 0 0 1 2 CURRENT FLOWS INTO OUTPUT PIN
REVERSE OUTPUT CURRENT (A)
Figure 4. Reverse Output Current
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open circuit. Current flow back into the output will follow the curve shown in Figure 4. The rise in reverse output current above 7V occurs from the breakdown of the 7V clamp on the ADJ pin. With a resistor divider on the regulator output, this current will be reduced depending on the size of the resistor divider. When the IN pin of the LT3014 is forced below the OUT pin or the OUT pin is pulled above the IN pin, input current will typically drop to less than 2A. This can happen if the input of the LT3014 is connected to a discharged (low voltage) battery and the output is held up by either a backup battery or a second regulator circuit. The state of the SHDN pin will have no effect on the reverse output current when the output is pulled above the input.
ADJ PIN ESD CLAMP 345678 OUTPUT VOLTAGE (V) 9 10
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LT3014
TYPICAL APPLICATIO S
5V Buck Converter with Low Current Keep Alive Backup
D2 D1N914 6 VIN 5.5V* TO 60V BOOST 4 C3 4.7F 100V CERAMIC VIN LT1766 15 14 SHDN SYNC GND BIAS FB VC CC 1nF 10 12 R1 15.4k R2 4.99k SW 2 C2 0.33F
OPERATING CURRENT LOW HIGH
EFFICIENCY (%)
12
U
L1 15H
D1 10MQ060N
VOUT 5V 1A/20mA
+
C1 100F 10V SOLID TANTALUM
1, 8, 9, 16 11
IN LT3014 SHDN GND
OUT 3.92M ADJ 1.27M * FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY INCREASE L1 TO 30H FOR LOAD CURRENTS ABOVE 0.6A AND TO 60H ABOVE 1A
3014 TA03
Buck Converter Efficiency vs Load Current
100 VOUT = 5V L = 68H
VIN = 10V
90 VIN = 42V 80
70
60
50
0
0.25
0.75 1.00 0.50 LOAD CURRENT (A)
1.25
3014 TA04
3014f
LT3014
TYPICAL APPLICATIO S
LT3014 Automotive Application
IN 1F NO PROTECTION DIODE NEEDED! LT3014 SHDN GND OFF ON ADJ R2 OUT R1 1F LOAD: CLOCK, SECURITY SYSTEM ETC
VIN 12V (LATER 42V)
+
VIN 48V (72V TRANSIENT) 1F
OFF ON
Constant Brightness for Indicator LED over Wide Input Voltage Range
RETURN 1F OFF ON
U
LT3014 Telecom Application
IN LT3014 SHDN GND
OUT R1 NO PROTECTION DIODE NEEDED! R2 1F LOAD: SYSTEM MONITOR ETC
+ -
ADJ
BACKUP BATTERY
3014 TA05
IN
OUT LT3014
SHDN GND
ADJ RSET
3014 TA06
1F
-48V ILED = 1.22V/RSET -48V CAN VARY FROM -3.3V TO -80V
3014f
13
LT3014
PACKAGE DESCRIPTIO
0.62 MAX
0.95 REF
3.85 MAX 2.62 REF
RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR
0.20 BSC 1.00 MAX DATUM `A'
0.30 - 0.50 REF 0.09 - 0.20 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193
14
U
S5 Package 5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 2.80 BSC 1.50 - 1.75 (NOTE 4) PIN ONE 0.30 - 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 - 0.90 0.01 - 0.10 1.90 BSC
S5 TSOT-23 0302
3014f
LT3014
PACKAGE DESCRIPTIO U
DD Package 8-Lead Plastic DFN (3mm x 3mm)
(Reference LTC DWG # 05-08-1698)
R = 0.115 TYP 5 0.675 0.05 0.38 0.10 8 3.00 0.10 (4 SIDES) PACKAGE OUTLINE 0.25 0.05 0.50 BSC 2.38 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 TOP MARK (NOTE 6)
(DD8) DFN 1203
3.5 0.05 1.65 0.05 2.15 0.05 (2 SIDES)
1.65 0.10 (2 SIDES)
0.200 REF
0.75 0.05
4 0.25 0.05 2.38 0.10 (2 SIDES)
1 0.50 BSC
0.00 - 0.05
BOTTOM VIEW--EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON TOP AND BOTTOM OF PACKAGE
3014f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LT3014 RELATED PARTS
PART NUMBER LT1129 LT1175 LT1185 LT1761 LT1762 LT1763 DESCRIPTION 700mA, Micropower, LDO 500mA, Micropower Negative LDO 3A, Negative LDO 100mA, Low Noise Micropower, LDO 150mA, Low Noise Micropower, LDO 500mA, Low Noise Micropower, LDO COMMENTS VIN: 4.2V to 30V, VOUT(MIN) = 3.75V, VDO = 0.4V, IQ = 50A, ISD = 16A, DD, SOT-223, S8, TO220, TSSOP-20 Packages VIN: -20V to -4.3V, VOUT(MIN) = -3.8V, VDO = 0.50V, IQ = 45A, ISD = 10A, DD, SOT-223, S8 Packages VIN: -35V to -4.2V, VOUT(MIN) = -2.40V, VDO = 0.80V, IQ = 2.5mA, ISD <1A, TO220-5 Package VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 20A, ISD <1A, ThinSOT Package VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 25A, ISD <1A, MS8 Package VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 30A, ISD <1A, S8 Package VIN: 2.7V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD <1A, DD, TO220 Packages VIN: 1.6V to 6.5V, VOUT(MIN) = 1.25V, VDO = 0.08V, IQ = 40A, ISD <1A, ThinSOT Package VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.27V, IQ = 30A, ISD <1A, MS8 Package VIN: 2.1V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD <1A, DD, TO220, SOT Packages VIN: -1.9V to -20V, VOUT(MIN) = -1.21V, VDO = 0.34V, IQ = 30A, ISD = 3A, ThinSOT Package VIN: 3V to 80V, VOUT(MIN) = 1.28V, VDO = 0.3V, IQ = 30A, ISD <1A, MS8E Package VIN: 0.9V to 10V, VOUT(MIN) = 0.20V, VDO = 0.15V, IQ = 120A, ISD <1A, DFN, MS8 Packages VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 40A, ISD <1A, DFN, MS10 Packages VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 60A, ISD <1A, DFN, TSSOP-16E Packages VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 40A, ISD <1A, DFN, MS10E Packages VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 60A, ISD <1A, DFN, TSSOP-16E Packages
LT1764/LT1764A 3A, Low Noise, Fast Transient Response, LDO LTC1844 LT1962 150mA, Very Low Dropout LDO 300mA, Low Noise Micropower, LDO
LT1963/LT1963A 1.5A, Low Noise, Fast Transient Response, LDO LT1964 LT3010 LT3020 LT3023 LT3024 LT3027 LT3028 200mA, Low Noise Micropower, Negative LDO 50mA, 80V, Low Noise Micropower, LDO 100mA, Low VIN, Low VOUT Micropower, VLDO Dual 100mA, Low Noise Micropower, LDO Dual 100mA/500mA, Low Noise Micropower, LDO Dual 100mA, Low Noise LDO with Independent Inputs Dual 100mA/500mA, Low Noise LDO with Independent Inputs
3014f
16
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507
LT/TP 0205 1K * PRINTED IN USA
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2005

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