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Final Electrical Specifications
LT1963 Series 1.5A, Low Noise, Fast Transient Response LDO Regulators
April 2000
FEATURES
s s s s s s s s s s s s s s s
DESCRIPTIO
Optimized for Fast Transient Response Output Current: 1.5A Dropout Voltage: 340mV Low Noise: 40VRMS (10Hz to 100kHz) 1mA Quiescent Current No Protection Diodes Needed Controlled Quiescent Current in Dropout Fixed Output Voltages: 1.8V, 2.5V, 3.3V Adjustable Output from 1.21V to 20V < 1A Quiescent Current in Shutdown Stable with 10F Output Capacitor Stable with Ceramic Capacitors Reverse Battery Protection No Reverse Current Thermal Limiting
APPLICATIO S
s s
3.3V to 2.5V Logic Power Supplies Post Regulator for Switching Supplies
The LT (R)1963 is a low dropout regulator optimized for fast transient response. The device is capable of supplying 1.5A of output current with a dropout voltage of 340mV. Operating quiescent current is 1mA, dropping to < 1A in shutdown. Quiescent current is well controlled; it does not rise in dropout as it does with many other regulators. In addition to fast transient response, the LT1963 has very low output noise which makes the device ideal for sensitive RF supply applications. Output voltage range is from 1.21V to 20V. The LT1963 regulators are stable with output capacitors as low as 10F. 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 in fixed output voltages of 1.8V, 2.5V, 3.3V and as an adjustable device with a 1.21V reference voltage. The LT1963 regulators are available in 5-lead TO-220, DD, 3-lead SOT-223 and 8-lead SO packages
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
400
3.3V to 2.5V Regulator
DROPOUT VOLTAGE (mV)
IN 10F OUT LT1963-2.5 SHDN SENSE 2.5V 1.5A 10F
350 300 250 200 150 100 50 0 0 0.2 0.4 0.6 0.8 1.0 1.2 OUTPUT CURRENT (A) 1.4 1.6
1963 TA02
+
VIN > 3V
+
GND
1963 TA01
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.
U
Dropout Voltage
U
U
1
LT1963 Series
ABSOLUTE
AXI U
RATI GS (Note 1)
SHDN Pin Voltage ................................................. 20V Output Short-Circuit Duration ......................... Indefinite Operating Junction Temperature Range - 45C to 125C Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C
IN Pin Voltage ........................................................ 20V OUT Pin Voltage .................................................... 20V Input to Output Differential Voltage (Note 2) ......... 20V SENSE Pin Voltage ............................................... 20V ADJ Pin Voltage ...................................................... 7V
PACKAGE/ORDER I FOR ATIO
FRONT VIEW 5 4 TAB IS GND 3 2 1 Q PACKAGE 5-LEAD PLASTIC DD SENSE/ADJ* OUT GND IN SHDN
ORDER PART NUMBER LT1963EQ LT1963EQ-1.8 LT1963EQ-2.5 LT1963EQ-3.3
*PIN 5 = SENSE FOR LT1963-1.8/LT1963-2.5/LT1963-3.3 = ADJ FOR LT1963 TJMAX = 150C, JA = 30C/ W
ORDER PART NUMBER
FRONT VIEW 1 TAB IS GND 2 3 OUT GND IN
LT1963EST-1.8 LT1963EST-2.5 LT1963EST-3.3 ST PART MARKING 196318 196325 196333
ST PACKAGE 3-LEAD PLASTIC SOT-223
TJMAX = 150C, JA = 50C/ W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25C. (Note 3)
PARAMETER CONDITIONS
q
Minimum Input Voltage (Notes 4,12) ILOAD = 0.5A ILOAD = 1.5A Regulated Output Voltage (Note 5) LT1963-1.8 LT1963-2.5 LT1963-3.3 VIN = 2.3V, ILOAD = 1mA 2.8V < VIN < 20V, 1mA < ILOAD < 1.5A VIN = 3V, ILOAD = 1mA 3.5V < VIN < 20V, 1mA < ILOAD < 1.5A VIN = 3.8V, ILOAD = 1mA 4.3V < VIN < 20V, 1mA < ILOAD < 1.5A
2
U
U
W
WW
U
W
FRONT VIEW 5 4 3 2 1 TAB IS GND T PACKAGE 5-LEAD PLASTIC TO-220 SENSE/ADJ* OUT GND IN SHDN
ORDER PART NUMBER LT1963ET LT1963ET-1.8 LT1963ET-2.5 LT1963ET-3.3
*PIN 5 = SENSE FOR LT1963-1.8/LT1963-2.5/LT1963-3.3 = ADJ FOR LT1963 TJMAX = 150C, JA = 50C/ W
ORDER PART NUMBER
TOP VIEW OUT 1 SENSE/ADJ* 2 GND 3 NC 4 8 7 6 5 IN GND GND SHDN
LT1963ES8 LT1963ES8-1.8 LT1963ES8-2.5 LT1963ES8-3.3 S8 PART MARKING 1963 196318 196325 196333
S8 PACKAGE 8-LEAD PLASTIC SO
*PIN 2 = SENSE FOR LT1963-1.8/LT1963-2.5/LT1963-3.3 = ADJ FOR LT1963 TJMAX = 150C, JA = 70C/ W
MIN
TYP 1.9 2.1
MAX 2.5 1.827 1.854 2.538 2.575 3.350 3.400
UNITS V V V V V V V V
q q q
1.773 1.737 2.462 2.412 3.250 3.200
1.800 1.800 2.500 2.500 3.300 3.300
LT1963 Series
ELECTRICAL CHARACTERISTICS
The q denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25C. (Note 2)
PARAMETER ADJ Pin Voltage (Notes 4, 5) Line Regulation CONDITIONS LT1963 LT1963-1.8 LT1963-2.5 LT1963-3.3 LT1963 (Note 4) LT1963-1.8 LT1963-2.5 LT1963-3.3 VIN = 2.21V, ILOAD = 1mA 2.21V < VIN < 20V, 1mA < ILOAD < 1.5A VIN = 2.3V to 20V, ILOAD = 1mA VIN = 3V to 20V, ILOAD = 1mA VIN = 3.8V to 20V, ILOAD = 1mA VIN = 2.21V to 20V, ILOAD = 1mA VIN = 2.8V, ILOAD = 1mA to 1.5A VIN = 2.8V, ILOAD = 1mA to 1.5A VIN = 3.5V, ILOAD = 1mA to 1.5A VIN = 3.5V, ILOAD = 1mA to 1.5A VIN = 4.3V, ILOAD = 1mA to 1.5A VIN = 4.3V, ILOAD = 1mA to 1.5A
q q q q q q
MIN 1.192 1.174
TYP 1.210 1.210 2.5 3.0 3.5 1.5 2 2.5
MAX 1.228 1.246 10 10 10 10 10 20 15 30 20 35 8 15 0.06 0.10 0.17 0.22 0.27 0.35 0.45 0.55 1.5 1.6 5.5 25 120 10 2 1 30 1
UNITS V V mV mV mV mV mV mV mV mV mV mV mV mV V V V V V V V V mA mA mA mA mA VRMS A V V A A A dB A A
Load Regulation
q
3
q
LT1963 (Note 4) VIN = 2.5V, ILOAD = 1mA to 1.5A VIN = 2.5V, ILOAD = 1mA to 1.5A Dropout Voltage VIN = VOUT(NOMINAL) (Notes 6, 7, 12) ILOAD = 1mA ILOAD = 1mA ILOAD = 100mA ILOAD = 100mA ILOAD = 500mA ILOAD = 500mA ILOAD = 1.5A ILOAD = 1.5A GND Pin Current VIN = VOUT(NOMINAL) + 1V (Notes 6, 8) ILOAD = 0mA ILOAD = 1mA ILOAD = 100mA ILOAD = 500mA ILOAD = 1.5A COUT = 10F, ILOAD = 1.5A, BW = 10Hz to 100kHz (Notes 4, 9) VOUT = Off to On VOUT = On to Off VSHDN = 0V VSHDN = 20V VIN = 6V, VSHDN = 0V VIN - VOUT = 1.5V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 0.75A VIN = 7V, VOUT = 0V VIN = VOUT(NOMINAL) + 1V, VOUT = - 0.1V Q, T, SO-8 Packages VIN = - 20V, VOUT = 0V ST Package VIN = - 20V, VOUT = 0V LT1963-1.8 LT1963-2.5 LT1963-3.3 LT1963 (Note 4) VOUT = 1.8V, VIN < 1.8V VOUT = 2.5V, VIN < 2.5V VOUT = 3.3V, VIN < 3.3V VOUT = 1.21V, VIN < 1.21V
2
q
0.02
q
0.10
q
0.19
q
0.34
q q q q q q
1.0 1.1 3.8 15 80 40 3
Output Voltage Noise ADJ Pin Bias Current Shutdown Threshold SHDN Pin Current (Note 10) Quiescent Current in Shutdown Ripple Rejection Current Limit Input Reverse Leakage Current (Note 13) Reverse Output Current (Note 11)
q q
0.25
0.90 0.75 0.01 7 0.01
55
63 2
q q q
1.6 1 2 600 600 600 300 1200 1200 1200 600
mA mA A A A A
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Absolute maximum input to output differential voltage can not be achieved with all combinations of rated IN pin and OUT pin voltages. With the IN pin at 20V, the OUT pin may not be pulled below 0V. The total measured voltage from IN to OUT can not exceed 20V.
Note 3: The LT1963 regulators are tested and specified under pulse load conditions such that TJ TA. The LT1963 is 100% tested at TA = 25C. Performance at - 40C and 125C is assured by design, characterization and correlation with statistical process controls. Note 4: The LT1963 (adjustable version) is tested and specified for these conditions with the ADJ pin connected to the OUT pin.
3
LT1963 Series
ELECTRICAL CHARACTERISTICS
Note 5: 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 6: To satisfy requirements for minimum input voltage, the LT1963 (adjustable version) is tested and specified for these conditions with an external resistor divider (two 4.12k resistors) for an output voltage of 2.4V. The external resistor divider will add a 300A DC load on the output. Note 7: Dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. In dropout, the output voltage will be equal to: VIN - VDROPOUT. Note 8: GND pin current is tested with VIN = VOUT(NOMINAL) + 1V and a current source load. The GND pin current will decrease at higher input voltages. Note 9: ADJ pin bias current flows into the ADJ pin. Note 10: SHDN pin current flows into the SHDN pin. Note 11: 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 the GND pin. Note 12. For the LT1963 and LT1963-1.8 dropout voltage will be limited by the minimum input voltage specification under some output voltage/ load conditions. Note 13. For the ST package, the input reverse leakage current increases due to the additional reverse leakage current for the SHDN pin, which is tied internally to the IN pin.
PI FU CTIO S
OUT: Output. The output supplies power to the load. A minimum output capacitor of 10F 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. SENSE: Sense. For fixed voltage versions of the LT1963 (LT1963-1.8/LT1963-2.5/LT1963-3.3), the SENSE pin is the input to the error amplifier. Optimum regulation will be obtained at the point where the SENSE pin is connected to the OUT pin of the regulator. In critical applications, small voltage drops are caused by the resistance (RP) of PC traces between the regulator and the load. These may be eliminated by connecting the SENSE pin to the output at the load as shown in Figure 1 (Kelvin Sense Connection). Note that the voltage drop across the external PC traces will add to the dropout voltage of the regulator. The SENSE pin bias current is 600A at the nominal rated output voltage. The SENSE pin can be pulled below ground (as in a dual supply system where the regulator load is returned to a negative supply) and still allow the device to start and operate. ADJ: Adjust. For the adjustable LT1963, this is the input to the error amplifier. This pin is internally clamped to 7V. It has a bias current of 3A which flows into the pin. The ADJ pin voltage is 1.21V referenced to ground and the output voltage range is 1.21V to 20V. SHDN: Shutdown. The SHDN pin is used to put the LT1963 regulators 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 open-collector logic with a pull-up resistor. The pull-up resistor is required to supply the pull-up current of the open-collector gate, normally several microamperes, and the SHDN pin current, typically 7A. If unused, the SHDN pin must be connected to VIN. The device will be in the low power shutdown state if the SHDN pin is not connected. IN: 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 1F to 10F is sufficient. The LT1963 regulators are designed to withstand reverse voltages on the IN pin with respect to ground and the OUT pin. In the case of a reverse input, which can happen if a battery is plugged in backwards, the device will act as if there is a diode in series with its input. There will be no reverse current flow into the regulator and no reverse voltage will appear at the load. The device will protect both itself and the load.
IN LT1963 OUT RP
4
U
U
U
+
VIN
SHDN
SENSE GND RP
+
LOAD
1963 F01
Figure 1. Kelvin Sense Connection
LT1963 Series
APPLICATIO S I FOR ATIO
The LT1963 series are 1.5A low dropout regulators optimized for fast transient response. The devices are capable of supplying 1.5A at a dropout voltage of 350mV. The low operating quiescent current (1mA) drops to less than 1A in shutdown. In addition to the low quiescent current, the LT1963 regulators incorporate several protection features which make them ideal for use in battery-powered systems. The devices are 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 LT1963-X acts like it has a diode in series with its output and prevents reverse current flow. Additionally, in dual supply applications where the regulator load is returned to a negative supply, the output can be pulled below ground by as much as 20V and still allow the device to start and operate. Adjustable Operation The adjustable version of the LT1963 has an output voltage range of 1.21V to 20V. 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 ADJ pin at 1.21V referenced to ground. The current in R1 is then equal to 1.21V/R1 and the current in R2 is the current in R1 plus the ADJ pin bias current. The ADJ pin bias current, 3A at 25C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure 2. The value of R1 should be less than 4.17k 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.
IN VIN LT1963 ADJ GND R1
1963 F02
OUT R2
VOUT
CHANGE IN VALUE (%)
+
R2 VOUT = 1.21V 1 + + (IADJ )(R2) R1 VADJ = 1.21V IADJ = 3A AT 25C OUTPUT RANGE = 1.21V TO 20V
Figure 2. Adjustable Operation
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The adjustable device is tested and specified with the ADJ pin tied to the OUT pin for an output voltage of 1.21V. Specifications for output voltages greater than 1.21V will be proportional to the ratio of the desired output voltage to 1.21V: VOUT/1.21V. For example, load regulation for an output current change of 1mA to 1.5A is - 3mV typical at VOUT = 1.21V. At VOUT = 5V, load regulation is: (5V/1.21V)(-3mV) = - 12.4mV Output Capacitance and Transient Response The LT1963 regulators are 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 10F with an ESR of 3 or less is recommended to prevent oscillations. Larger values of output capacitance can decrease the peak deviations and provide improved transient response for larger load current changes. Bypass capacitors, used to decouple individual components powered by the LT1963, will increase the effective output capacitor value. Extra consideration must be given to the use of ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior over 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 3 and 4. When used with a 5V regulator, a 10F Y5V capacitor can exhibit
20 0 X5R -20 -40 -60 Y5V -80 -100 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F 0 2 4 8 6 10 12 DC BIAS VOLTAGE (V) 14 16
1963 F03
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Figure 3. Ceramic Capacitor DC Bias Characteristics
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LT1963 Series
APPLICATIO S I FOR ATIO
40 20
CHANGE IN VALUE (%)
0 -20 -40 -60 -80 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F 50 25 75 0 TEMPERATURE (C) Y5V
X5R
-100 -50 -25
100
125
1963 F04
Figure 4. Ceramic Capacitor Temperature Characteristics
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, 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 is limited by the maximum rated junction temperature (125C). The power dissipated by the device is 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 estimated using the GND Pin Current specification in the Electrical Characteristics table. Power dissipation will be equal to the sum of the two components listed above. The LT1963 series regulators have internal thermal limiting designed to protect the device during overload
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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 tables list thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 1/16" FR-4 board with one ounce copper.
Table 1. Q Package, 5-Lead DD
COPPER AREA TOPSIDE* BACKSIDE 2500mm2 1000mm 125mm
2 2
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BOARD AREA 2500mm2 2500mm 2500mm
2 2
THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 23C/W 25C/W 33C/W
2500mm2 2500mm 2500mm
2 2
*Device is mounted on topside
Table 2. SO-8 Package, 8-Lead SO
COPPER AREA TOPSIDE* BACKSIDE 2500mm2 1000mm 225mm
2 2
BOARD AREA 2500mm2 2500mm 2500mm
2 2
THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 55C/W 55C/W 63C/W 69C/W
2500mm2 2500mm 2500mm
2 2
100mm2
2500mm2
2500mm2
*Device is mounted on topside.
Table 3. SOT-223 Package, 3-Lead SOT-223
COPPER AREA TOPSIDE* BACKSIDE 2500mm2 1000mm 225mm
2 2
BOARD AREA 2500mm2 2500mm 2500mm 1000mm 1000mm
2 2
THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 42C/W 42C/W 50C/W 56C/W 49C/W 52C/W
2500mm2 2500mm 2500mm 1000mm 0mm
2 2 2
100mm2 1000mm 1000mm
2 2
2500mm2
2
2500mm2
2 2
*Device is mounted on topside.
T Package, 5-Lead TO-220
Thermal Resistance (Junction-to-Case) = 4C/W
LT1963 Series
APPLICATIO S I FOR ATIO
Calculating Junction Temperature
Example: Given an output voltage of 3.3V, an input voltage range of 4V to 6V, an output current range of 0mA to 500mA 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) = 500mA VIN(MAX) = 6V IGND at (IOUT = 500mA, VIN = 6V) = 10mA So, P = 500mA(6V - 3.3V) + 10mA(6V) = 1.41W Using a DD package, the thermal resistance will be in the range of 23C/W to 33C/W depending on the copper area. So the junction temperature rise above ambient will be approximately equal to: 1.41W(28C/W) = 39.5C The maximum junction temperature will then be equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature or: TJMAX = 50C + 39.5C = 89.5C Protection Features The LT1963 regulators incorporate several protection features which make them 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 devices are protected against reverse input voltages, reverse output 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 20V. Current flow into the device will be limited to less than 1mA (typically less than 100A) and no negative voltage
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will appear at the output. The device will protect both itself and the load. This provides protection against batteries that can be plugged in backward. The output of the LT1963 can be pulled below ground without damaging the device. If the input is left open circuit or grounded, the output can be pulled below ground by 20V. For fixed voltage versions, the output will act like a large resistor, typically 5k or higher, limiting current flow to typically less than 600A. For adjustable versions, the output will act like an open circuit; no current will flow out of the pin. If the input is powered by a voltage source, the output will source the short-circuit current of the device and will protect itself by thermal limiting. In this case, grounding the SHDN pin will turn off the device and stop the output from sourcing the short-circuit current. The ADJ pin of the adjustable device 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 5k) in series with a diode when pulled above ground. 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 1.21V reference when the output is forced to 20V. 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 13V difference between OUT and ADJ pins divided by the 5mA maximum current into the ADJ pin yields a minimum top resistor value of 2.6k. 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 open circuit. Current flow back into the output will follow the curve shown in Figure 5. When the IN pin of the LT1963 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
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LT1963 Series
APPLICATIO S I FOR ATIO
input of the device 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
5.0
REVERSE OUTPUT CURRENT (mA)
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 0
LT1963-3.3 VOUT = VFB
Figure 5. Reverse Output Current
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
0.256 (6.502)
0.060 (1.524)
0.060 (1.524) TYP
0.060 (1.524)
0.183 (4.648)
0.330 - 0.370 (8.382 - 9.398)
0.075 (1.905) 0.300 (7.620) BOTTOM VIEW OF DD PAK HATCHED AREA IS SOLDER PLATED COPPER HEAT SINK +0.012 0.143 -0.020 0.067 (1.70) 0.028 - 0.038 BSC (0.711 - 0.965) 0.013 - 0.023 (0.330 - 0.584)
(
+0.305 3.632 -0.508
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the SHDN pin will have no effect on the reverse output current when the output is pulled above the input.
LT1963 VOUT = VADJ LT1963-2.5 VOUT = VFB LT1963-1.8 VOUT = VFB TJ = 25C VIN = 0V CURRENT FLOWS INTO OUTPUT PIN 1 2 345678 OUTPUT VOLTAGE (V) 9 10
1963 F05
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Q Package 5-Lead Plastic DD Pak
(LTC DWG # 05-08-1461)
0.390 - 0.415 (9.906 - 10.541) 15 TYP
0.165 - 0.180 (4.191 - 4.572)
0.045 - 0.055 (1.143 - 1.397) +0.008 0.004 -0.004
0.059 (1.499) TYP
(
+0.203 0.102 -0.102
)
0.095 - 0.115 (2.413 - 2.921) 0.050 0.012 (1.270 0.305)
Q(DD5) 1098
)
LT1963 Series
PACKAGE DESCRIPTIO
0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0- 8 TYP
0.014 - 0.019 (0.355 - 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
0.016 - 0.050 (0.406 - 1.270)
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Dimensions in inches (millimeters) unless otherwise noted.
S8 Package 8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 - 0.197* (4.801 - 5.004) 8 7 6 5
0.228 - 0.244 (5.791 - 6.197)
0.150 - 0.157** (3.810 - 3.988)
1
2
3
4
0.053 - 0.069 (1.346 - 1.752)
0.004 - 0.010 (0.101 - 0.254)
0.050 (1.270) BSC
SO8 1298
9
LT1963 Series
PACKAGE DESCRIPTIO
0.248 - 0.264 (6.30 - 6.71) 0.114 - 0.124 (2.90 - 3.15)
0.264 - 0.287 (6.70 - 7.30) 0.130 - 0.146 (3.30 - 3.71)
0.0905 (2.30) NOM
0.071 (1.80) MAX
0.024 - 0.033 (0.60 - 0.84) 0.181 (4.60) NOM
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Dimensions in inches (millimeters) unless otherwise noted.
ST Package 3-Lead Plastic SOT-223
(LTC DWG # 05-08-1630)
0.033 - 0.041 (0.84 - 1.04)
10 - 16 10 MAX 0.010 - 0.014 (0.25 - 0.36)
10 - 16 0.012 (0.31) MIN 0.0008 - 0.0040 (0.0203 - 0.1016)
ST3 (SOT-233) 1298
LT1963 Series
PACKAGE DESCRIPTIO
0.390 - 0.415 (9.906 - 10.541)
0.230 - 0.270 (5.842 - 6.858) 0.460 - 0.500 (11.684 - 12.700) 0.570 - 0.620 (14.478 - 15.748) 0.330 - 0.370 (8.382 - 9.398) 0.700 - 0.728 (17.78 - 18.491) 0.620 (15.75) TYP
BSC
0.067 (1.70)
0.028 - 0.038 (0.711 - 0.965)
U
Dimensions in inches (millimeters) unless otherwise noted.
T Package 5-Lead Plastic TO-220 (Standard)
(LTC DWG # 05-08-1421)
0.147 - 0.155 (3.734 - 3.937) DIA
0.165 - 0.180 (4.191 - 4.572)
0.045 - 0.055 (1.143 - 1.397)
SEATING PLANE 0.152 - 0.202 0.260 - 0.320 (3.861 - 5.131) (6.60 - 8.13)
0.095 - 0.115 (2.413 - 2.921) 0.155 - 0.195* (3.937 - 4.953) 0.013 - 0.023 (0.330 - 0.584)
0.135 - 0.165 (3.429 - 4.191)
* MEASURED AT THE SEATING PLANE
T5 (TO-220) 0399
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LT1963 Series RELATED PARTS
PART NUMBER LT1120 LT1121 LT1129 LT1175 LT1521 LT1529 LT1772 LTC1627 LT1761 Series LT1762 Series LT1763 Series LT1764 Series DESCRIPTION 125mA Low Dropout Regulator with 20A IQ 150mA Micropower Low Dropout Regulator 700mA Micropower Low Dropout Regulator 500mA Negative Low Dropout Micropower Regulator 300mA Low Dropout Micropower Regulator with Shutdown 3A Low Dropout Regulator with 50A IQ Constant Frequency, Current Mode Step-Down DC/DC Controller High Efficiency Synchronous Step-Down Switching Regulator 100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23 150mA, Low Noise, LDO Micropower Regulators 500mA, Low Noise, LDO Micropower Regulators 3A, Fast Transient Response Low Dropout Regulator COMMENTS Includes 2.5V Reference and Comparator 30A IQ, SOT-223 Package 50A Quiescent Current 45A IQ, 0.26V Dropout Voltage, SOT-223 Package 15A IQ, Reverse Battery Protection 500mV Dropout Voltage Up to 94% Efficiency, SOT-23 Package, 100% Duty Cycle Burst ModeTM Operation, Monolithic, 100% Duty Cycle 20A Quiescent Current, 20VRMS Noise, SOT-23 Package 25A Quiescent Current, 20VRMS Noise, MSOP Package 30A Quiescent Current, 20VRMS Noise, SO-8 Package 230mV Dropout Voltage, 40VRMS Noise
Burst Mode is a trademark of Linear Technology Corporation.
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Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com
1963i LT/TP 0400 4K * PRINTED IN USA
(c) LINEAR TECHNOLOGY CORPORATION 2000

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